Acquired Immunodeficiency Syndrome

Acquired immunodeficiency syndrome (AIDS) is the advanced clinical state of infection with human immunodeficiency virus type 1 (HIV-1) or type 2 (HIV-2), not a synonym for every HIV infection. In the U.S. CDC surveillance framework, AIDS is HIV infection stage 3; this numbering is framework-specific. Persistent viral replication, mucosal immune injury, chronic immune activation, and progressive failure of CD4 T-cell homeostasis produce severe cell-mediated immunodeficiency. Subject to the framework's stage-0 precedence rule, AIDS is classified by severe CD4 depletion or an AIDS-defining illness and is manifested by opportunistic infections, selected malignancies, and sometimes severe HIV-associated neurologic disease. Combination antiretroviral therapy suppresses viral replication and permits immune reconstitution but does not eradicate long-lived cellular reservoirs.

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2
Definitions
10
Pathophys.
6
Phenotypes
20
Pathograph
2
Medical Actions
3
Differentials
22
References
2
Deep Research
📘

Definitions

2
CDC HIV stage-3 surveillance case definition
In the U.S. CDC framework, AIDS is HIV infection classified as stage 3. The surveillance framework uses severe CD4 depletion and AIDS-defining clinical conditions; it is intended for population surveillance and is not, by itself, a clinical decision rule for an individual patient.
CASE_DEFINITION United States public-health surveillance in people with confirmed HIV infection
Show evidence (2 references)
PMID:24717910 SUPPORT Other
"A confirmed case can be classified in one of five HIV infection stages (0, 1, 2, 3, or unknown); early infection, recognized by a negative HIV test within 6 months of HIV diagnosis, is classified as stage 0, and acquired immunodeficiency syndrome (AIDS) is classified as stage 3."
The CDC surveillance definition explicitly identifies AIDS as HIV infection stage 3.
PMID:24717910 SUPPORT Other
"The surveillance case definition is intended primarily for monitoring the HIV infection burden and planning for prevention and care on a population level, not as a basis for clinical decisions for individual patients."
This states the intended population-surveillance scope and its clinical-use limitation.
Historical adult and adolescent CD4-depletion threshold
The 1993 expanded U.S. CDC surveillance definition for adolescents and adults included HIV infection with a CD4 T-cell count below 200 cells per microliter or a CD4 percentage below 14 percent.
CASE_DEFINITION 1993 U.S. CDC expanded AIDS surveillance definition for adolescents and adults
Show evidence (1 reference)
PMID:8093740 SUPPORT Other
"Consistent with the 1993 revised classification system, CDC has also expanded the AIDS surveillance case definition to include all HIV-infected persons who have less than 200 CD4+ T-lymphocytes/microL, or a CD4+ T-lymphocyte percentage of total lymphocytes of less than 14."
The CDC publication gives the exact count and percentage thresholds.

Pathophysiology

10
Persistent HIV Infection and Replication
HIV establishes ongoing infection in susceptible immune cells. Viral replication drives pathogenesis, while the resulting immunodeficiency reflects both direct viral effects and dysregulated host immune homeostasis.
CD4-positive, alpha-beta T cell CL:0000624 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves CD4-positive, alpha-beta T cell (CL:0000624). CL:0000624 is a cell type from the Cell Ontology.
viral process GO:0016032 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves abnormal viral process (GO:0016032). GO:0016032 is a biological process from the Gene Ontology. ⚠ ABNORMAL
Show evidence (1 reference)
PMID:23772614 SUPPORT Other
"Thus, the onset of overt immune deficiency appears to be intimately linked with CD4(+) memory T-cell dynamics and reflects the complex interplay of direct viral cytopathogenicity and the indirect effects of persistent immune activation on CD4(+) memory T-cell proliferation, differentiation, and survival."
This supports viral and host-homeostatic contributions to AIDS pathogenesis.
Early Mucosal CD4 T-Cell Loss and Gut Barrier Injury
Acute HIV infection causes marked depletion of mucosal CD4 memory T cells, persistent mucosal inflammation, and epithelial barrier injury.
CD4-positive, alpha-beta T cell CL:0000624 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves CD4-positive, alpha-beta T cell (CL:0000624). CL:0000624 is a cell type from the Cell Ontology.
small intestine UBERON:0002108 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in small intestine (UBERON:0002108). UBERON:0002108 is an anatomical location from the Uberon multi-species anatomy ontology.
Show evidence (1 reference)
PMID:23297256 SUPPORT Other
"In vivo studies demonstrated that HIV/SIV-associated microbial translocation results from a series of immunopathological events occurring at the GI mucosa: (i) early and severe mucosal CD4(+) depletion, (ii) mucosal immune hyperactivation/persistent inflammation; (iii) damage to the integrity of..."
This review describes the linked mucosal CD4 loss, inflammation, and epithelial injury.
Microbial Translocation and Chronic Immune Activation
Microbial products crossing the damaged gut barrier contribute to persistent innate and adaptive immune activation during chronic HIV infection.
T cell activation GO:0042110 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased T cell activation (GO:0042110). GO:0042110 is a biological process from the Gene Ontology. ↑ INCREASED
Show evidence (1 reference)
PMID:23297256 SUPPORT Other
"While the mechanisms by which microbial translocation causes immune activation remain controversial, a key pathogenic event appears to be innate immunity activation via Toll-like receptors and other pathogen recognition receptors."
This supports a contributory innate-activation mechanism while preserving uncertainty.
Abortive HIV Infection and Caspase-1 Pyroptosis
In ex vivo human lymphoid aggregates, abortive HIV-1 infection of quiescent CD4 T cells activates caspase-1, causing inflammatory pyroptotic cell death. This is a contributory experimental mechanism, not a universal quantitative estimate for every person with AIDS.
CD4-positive, alpha-beta T cell CL:0000624 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves CD4-positive, alpha-beta T cell (CL:0000624). CL:0000624 is a cell type from the Cell Ontology.
pyroptotic inflammatory response GO:0070269 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased pyroptotic inflammatory response (GO:0070269). GO:0070269 is a biological process from the Gene Ontology. ↑ INCREASED
Show evidence (1 reference)
PMID:24356306 SUPPORT In Vitro
"Pyroptosis corresponds to an intensely inflammatory form of programmed cell death in which cytoplasmic contents and pro-inflammatory cytokines, including IL-1β, are released."
The ex vivo study characterizes the inflammatory cell-death mechanism.
Progressive CD4 T-Cell Depletion and Homeostatic Failure
Direct viral effects and chronic immune activation eventually overwhelm CD4 memory T-cell regeneration, lowering critical effector populations.
CD4-positive, alpha-beta T cell CL:0000624 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves CD4-positive, alpha-beta T cell (CL:0000624). CL:0000624 is a cell type from the Cell Ontology.
Show evidence (1 reference)
PMID:23772614 SUPPORT Other
"Ultimately, CD4(+) memory T-cell homeostasis fails and critical effector populations decline below the level necessary to prevent OI."
This supports progressive failure of CD4 homeostasis and loss of protective effector cells.
Severe Cell-Mediated Immunodeficiency
Profound loss of CD4 T-cell number and function marks overt AIDS and undermines immune control of opportunistic pathogens and oncogenic viruses.
CD4-positive, alpha-beta T cell CL:0000624 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves CD4-positive, alpha-beta T cell (CL:0000624). CL:0000624 is a cell type from the Cell Ontology.
Show evidence (1 reference)
PMID:23772614 SUPPORT Other
"Overall, these observations provide strong evidence that a profoundly impaired cellular immune response due to depletion of CD4+T cells and loss of CD4+T-cell function was the underlying cause of immunodeficiency present in these patients."
This supports CD4 loss and dysfunction as the basis of severe cellular immunodeficiency.
Opportunistic Infection Susceptibility
Severe cellular immunodeficiency permits AIDS-defining opportunistic infections; Pneumocystis pneumonia and esophageal candidiasis are representative manifestations rather than an exhaustive list.
Show evidence (1 reference)
PMID:16182595 SUPPORT Other
"Pulmonary infection caused by the opportunistic fungal organism Pneumocystis continues to be a leading AIDS defining illness."
This identifies Pneumocystis pneumonia as a leading AIDS-defining opportunistic illness.
Loss of Oncogenic-Virus Immune Control
AIDS-associated immune dysfunction reduces surveillance of HHV-8, Epstein-Barr virus, and oncogenic human papillomavirus, enabling selected malignancies.
Show evidence (1 reference)
PMID:12525676 SUPPORT Other
"Immunodeficiency alters the risk of cancer. Specific types of immune dysfunction are associated with different tumor risks, but most tumors are related to oncogenic viruses."
This supports oncogenic-virus-associated malignancy in the immunodeficient state.
CNS HIV Infection and Neuroinflammation
HIV can establish compartmentalized infection in CNS macrophage-lineage cells. Local immune activation, neuroinflammation, and neurotoxicity can contribute to severe HIV-associated cognitive disease.
microglial cell CL:0000129 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves microglial cell (CL:0000129). CL:0000129 is a cell type from the Cell Ontology.
brain UBERON:0000955 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in brain (UBERON:0000955). UBERON:0000955 is an anatomical location from the Uberon multi-species anatomy ontology.
Show evidence (1 reference)
PMID:25604237 SUPPORT Other
"Recent work suggests that the stage for HIV neuropathogenesis may be set with initial viral entry into the CNS, followed by initiation of pathogenetic processes including neuroinflammation and neurotoxicity, and establishment of local, compartmentalized HIV replication that may reflect a tissue..."
This review supports CNS infection, neuroinflammation, and neurotoxicity.
Persistent Cellular HIV Reservoir
Resting CD4 memory T cells and other cellular compartments can retain integrated provirus during suppressive ART, preventing eradication and enabling renewed infection if therapy stops.
CD4-positive, alpha-beta T cell CL:0000624 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves CD4-positive, alpha-beta T cell (CL:0000624). CL:0000624 is a cell type from the Cell Ontology.
Show evidence (3 references)
PMID:29744964 SUPPORT Other
"The HIV cellular reservoir comprises cells with HIV-DNA integrated into their genome, but trancriptionally silent, making the virus refractory to cART and to the action of the immune system."
This directly supports integrated, transcriptionally silent HIV persisting despite ART.
PMID:29744964 SUPPORT Other
"Numerous reports have described that the main HIV cellular reservoir is composed of resting CD4+ T-cells16–18. Importantly, replication-competent provirus from the latent reservoir is capable of reigniting new rounds of infection if therapy is interrupted4,5."
This supports resting CD4 T cells as a major reservoir and renewed infection after ART interruption.
PMID:37317962 SUPPORT In Vitro
"Outgrowth virus from parietal cortex MG in an individual with HIV productively infected both MG and PBMCs."
Human rapid-autopsy tissue with ex vivo viral outgrowth supports replication-competent HIV in brain microglia.

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Acquired Immunodeficiency Syndrome Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.

Phenotypes

6
Immune 1
Pneumocystis jirovecii Pneumonia HP:0020102 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Pneumocystis jirovecii pneumonia (HP:0020102). HP:0020102 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:16182595 SUPPORT Other
"Pulmonary infection caused by the opportunistic fungal organism Pneumocystis continues to be a leading AIDS defining illness."
This identifies Pneumocystis pneumonia as an AIDS-defining illness.
Integument 1
Kaposi Sarcoma Kaposi's sarcoma HP:0100726 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Kaposi's sarcoma (HP:0100726). HP:0100726 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:18366449 SUPPORT Human Clinical
"The three most frequent initial ADIs were Pneumocystis carinii (jirovecii) pneumonia (PCP) (15.6%), oesophageal candidiasis (14.3%) and Kaposi's sarcoma (13.9%) in the pre-cART period."
This cohort identifies Kaposi sarcoma as an initial AIDS-defining illness.
Other 4
Esophageal Candidiasis
Show evidence (1 reference)
PMID:18366449 SUPPORT Human Clinical
"The three most frequent initial ADIs were Pneumocystis carinii (jirovecii) pneumonia (PCP) (15.6%), oesophageal candidiasis (14.3%) and Kaposi's sarcoma (13.9%) in the pre-cART period."
This cohort explicitly identifies esophageal candidiasis as an initial AIDS-defining illness.
Invasive Cervical Cancer
Show evidence (1 reference)
PMID:8093740 SUPPORT Other
"This expansion includes the addition of three clinical conditions--pulmonary tuberculosis, recurrent pneumonia, and invasive cervical cancer--and retains the 23 clinical conditions in the AIDS surveillance case definition published in 1987; it is to be used by all states for AIDS case reporting..."
The expanded CDC surveillance definition explicitly added invasive cervical cancer.
AIDS Dementia Complex
Show evidence (1 reference)
PMID:25604237 SUPPORT Other
"By 1987, the non-specific “subacute encephalitis” that widely affected patients with HIV was identified as the AIDS dementia complex (ADC, now termed HIV-associated dementia, or HAD), and was recognized as a manifestation of HIV itself rather than that of an alternate infection (2)."
This identifies AIDS dementia complex/HIV-associated dementia as a direct HIV manifestation.
💊

Medical Actions

2
Combination Antiretroviral Therapy
Category: Therapeutic Action: Antiretroviral TherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Antiretroviral Therapy (NCIT:C94631). NCIT:C94631 is a clinical intervention from the NCI Thesaurus. NCIT:C94631
Individualized combination ART suppresses HIV replication. Contemporary initial regimens for most adults use an integrase strand-transfer inhibitor with nucleoside or nucleotide reverse-transcriptase inhibitor components; regimen selection must account for clinical context, resistance, interactions, and HIV type.
Mechanism Target:
INHIBITS Persistent HIV Infection and Replication — Combination ART suppresses active viral replication.
Show evidence (1 reference)
PMID:36308326 SUPPORT Human Clinical
"Patients who started an InSTI achieved viral suppression and CD4+ T cell count above 350 cells/mm3significantly earlier."
This advanced-HIV cohort directly supports antiretroviral-regimen suppression of active HIV replication.
RESTORES Severe Cell-Mediated Immunodeficiency — Viral suppression permits partial CD4 immune reconstitution and reduces opportunistic disease.
Show evidence (1 reference)
PMID:11424971 SUPPORT Other
"Suppression of HIV-1 replication results in both laboratory and clinical evidence of immune restoration."
This review supports immune restoration after suppressive ART.
Show evidence (3 references)
PMID:39616604 SUPPORT Other
"For most people with HIV, initial regimens composed of an integrase strand transfer inhibitor (InSTI), specifically bictegravir or dolutegravir, with 2 (and in some cases 1) nucleoside or nucleotide reverse transcriptase inhibitors are recommended."
This provides current initial-regimen guidance for most adults with HIV.
PMID:36308326 SUPPORT Human Clinical
"In this large real-life prospective cohort study, a significant lower mortality, earlier viral suppression and earlier immune reconstitution were observed among patients with advanced HIV disease treated with InSTIs."
This advanced-HIV cohort supports viral suppression, immune reconstitution, and clinical benefit.
PMID:36982978 SUPPORT Other
"Antiretroviral drugs in clinical use were designed for HIV-1 and, unfortunately, some do not work as well, or do not work at all, for HIV-2."
This supports HIV type-specific antiretroviral regimen selection.
Context-Specific Opportunistic-Infection Prophylaxis
Category: Therapeutic Action: preventative therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is preventative therapy, annotated with Preventive Intervention (NCIT:C15843). NCIT:C15843 is a clinical intervention from the NCI Thesaurus. Ontology label: Preventive Intervention NCIT:C15843
Antimicrobial prophylaxis can reduce selected opportunistic infections in people with advanced immunosuppression. The agent, CD4 threshold, pathogen, geography, screening results, interactions, and concurrent ART determine the appropriate regimen; there is no single universal prophylaxis bundle.
Mechanism Target:
BYPASSES Opportunistic Infection Susceptibility — Prophylactic antimicrobials reduce selected infections during advanced immunosuppression while ART is initiated.
Show evidence (1 reference)
PMID:28723333 SUPPORT Human Clinical
"Patients in the enhanced-prophylaxis group had significantly lower rates of tuberculosis (P=0.02), cryptococcal infection (P=0.01), oral or esophageal candidiasis (P=0.02), death of unknown cause (P=0.03), and new hospitalization (P=0.03)."
The trial supports clinical prevention; BYPASSES denotes prevention despite, rather than correction of, the immune deficit.
Show evidence (1 reference)
PMID:28723333 SUPPORT Human Clinical
"Patients in the enhanced-prophylaxis group had significantly lower rates of tuberculosis (P=0.02), cryptococcal infection (P=0.01), oral or esophageal candidiasis (P=0.02), death of unknown cause (P=0.03), and new hospitalization (P=0.03)."
The trial documents condition-specific benefits of the evaluated prophylaxis bundle.
🔬

Biochemical Markers

2
CD4 T-Cell Count (Decreased)
Context: Absolute count and percentage are U.S. CDC surveillance-stage measures with age-specific thresholds. The count takes precedence, and percentage is used only when the count is missing. Stage 0 and a qualifying opportunistic illness can take precedence over the CD4 table. Values can rise after ART and must be interpreted with clinical history.
Pathograph Readouts
Readout Of Severe Cell-Mediated Immunodeficiency Threshold Dependent Diagnostic
For a person aged 6 years or older who does not meet stage-0 criteria, a CD4 count below 200 cells per microliter indicates U.S. CDC surveillance stage 3; a CD4 percentage below 14 percent is used only when the count is missing. Children younger than 6 years have age-specific stage-3 cutoffs.
Show evidence (3 references)
"TABLE. HIV infection stage* based on age-specific CD4+ T-lymphocyte count or CD4+ T-lymphocyte percentage of total lymphocytes Stage Age on date of CD4+ T-lymphocyte test <1 yr 1–5 yrs ≥6 yrs Cells/µL % Cells/µL % Cells/µL % 1 ≥1,500 ≥34 ≥1,000 ≥30 ≥500 ≥26 2 750–1,499 26–33 500–999 22–29..."
The official table supplies age-specific stage-3 CD4 count and percentage thresholds.
"The stage is based primarily on the CD4+ T-lymphocyte count; the CD4+ T-lymphocyte count takes precedence over the CD4 T-lymphocyte percentage, and the percentage is considered only if the count is missing."
This establishes count precedence and percentage use only when the count is missing.
"if the criteria for stage 0 are met, the stage is 0 regardless of criteria for other stages (CD4 T-lymphocyte test results and opportunistic illness diagnoses)"
This establishes stage-0 precedence over CD4 results and stage-3-defining illnesses.
Show evidence (1 reference)
PMID:8093740 SUPPORT Other
"The Centers for Disease Control and Prevention (CDC) has revised the classification system for HIV infection to emphasize the clinical importance of the CD4+ T-lymphocyte count in the categorization of HIV-related clinical conditions."
This establishes CD4 count as a central HIV-stage classification biomarker.
HIV Viral Load (Variable)
Context: Plasma HIV RNA monitors viral replication and treatment response; values can become suppressed with effective ART.
Pathograph Readouts
Pharmacodynamic Marker Of Persistent HIV Infection and Replication Positive Pharmacodynamic
Falling HIV RNA indicates pharmacodynamic suppression of viral replication by ART.
Show evidence (1 reference)
PMID:36308326 SUPPORT Human Clinical
"Patients who started an InSTI achieved viral suppression and CD4+ T cell count above 350 cells/mm3significantly earlier."
The advanced-HIV cohort uses viral suppression as a treatment-response readout.
Show evidence (1 reference)
PMID:36308326 SUPPORT Human Clinical
"The main outcomes were mortality, virological effectiveness (percentage of patients with viral load of ≤50 copies/mL) and immune restoration (percentage of patients with CD4+ T cell count above 350 cells/mm3)."
This supports viral load as a virologic-treatment outcome in advanced HIV disease.
🔬

Diagnosis

3
Confirm HIV Infection and Differentiate HIV-1 from HIV-2
AIDS classification first requires established HIV infection. Contemporary multitest algorithms include differentiation of HIV-1 and HIV-2.
diagnostic procedure NCIT:C18020 NCI Thesaurus (NCIT)
Results: Laboratory evidence confirms HIV infection and, where possible, distinguishes HIV-1 from HIV-2.
Show evidence (1 reference)
PMID:24717910 SUPPORT Other
"Laboratory criteria for defining a confirmed case now accommodate new multitest algorithms, including criteria for differentiating between HIV-1 and HIV-2 infection and for recognizing early HIV infection."
This supports confirmation and type differentiation before stage classification.
U.S. CDC CD4 Surveillance-Stage Classification
After HIV confirmation, apply the age-specific U.S. CDC surveillance table. Absolute CD4 count takes precedence; use percentage only if the count is missing, and apply stage-0 precedence before later-stage criteria.
diagnostic procedure NCIT:C18020 NCI Thesaurus (NCIT)
Results: At age 6 years or older, count below 200 cells per microliter indicates stage 3 when stage-0 criteria do not apply; percentage below 14 percent is used only when count is missing. Children younger than 6 years have higher age-specific stage-3 cutoffs.
Show evidence (3 references)
"TABLE. HIV infection stage* based on age-specific CD4+ T-lymphocyte count or CD4+ T-lymphocyte percentage of total lymphocytes Stage Age on date of CD4+ T-lymphocyte test <1 yr 1–5 yrs ≥6 yrs Cells/µL % Cells/µL % Cells/µL % 1 ≥1,500 ≥34 ≥1,000 ≥30 ≥500 ≥26 2 750–1,499 26–33 500–999 22–29..."
The official table supplies age-specific stage-3 CD4 count and percentage thresholds.
"The stage is based primarily on the CD4+ T-lymphocyte count; the CD4+ T-lymphocyte count takes precedence over the CD4 T-lymphocyte percentage, and the percentage is considered only if the count is missing."
This establishes count precedence and percentage use only when the count is missing.
"if the criteria for stage 0 are met, the stage is 0 regardless of criteria for other stages (CD4 T-lymphocyte test results and opportunistic illness diagnoses)"
This establishes stage-0 precedence before later-stage classification.
Assessment for AIDS-Defining Illnesses
In the U.S. CDC surveillance framework, evaluate confirmed HIV infection for stage-3 clinical conditions, including specified opportunistic infections and malignancies. This clinical route is distinct from diagnosing HIV infection itself.
diagnostic procedure NCIT:C18020 NCI Thesaurus (NCIT)
Results: When stage-0 criteria are not met, a qualifying AIDS-defining illness establishes stage 3 regardless of the CD4 result.
Show evidence (2 references)
"If a stage-3–defining opportunistic illness has been diagnosed, then the stage is 3 regardless of CD4 T-lymphocyte test results, unless the criteria described below for stage 0 are met."
This directly states the opportunistic-illness rule and its stage-0 exception.
PMID:18366449 SUPPORT Human Clinical
"The three most frequent initial ADIs were Pneumocystis carinii (jirovecii) pneumonia (PCP) (15.6%), oesophageal candidiasis (14.3%) and Kaposi's sarcoma (13.9%) in the pre-cART period."
This provides representative clinical AIDS-defining illnesses.
📈

Progression

1
Onset
Progression from untreated HIV infection to overt AIDS is variable and can take many years. Acute HIV illness occurs much earlier and is not the onset of AIDS.
Show evidence (1 reference)
PMID:23772614 SUPPORT Other
"Disease progression in untreated human immunodeficiency virus (HIV) infection can take many years, and it was originally hypothesized to be a consequence of slow, viral-mediated CD4(+) T-cell destruction."
This review supports a long and variable untreated interval before overt immunodeficiency.
🦠

Infectious Agent

2
Human immunodeficiency virus 1
HIV-1 is one of the two human lentiviruses that can cause AIDS.
Human immunodeficiency virus 1 NCBITaxon:11676 NCBI Taxonomy (NCBITaxon)
Show evidence (1 reference)
PMID:22229120 SUPPORT Other
"Acquired immunodeficiency syndrome (AIDS) of humans is caused by two lentiviruses, human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2)."
This review identifies HIV-1 as one of the two human lentiviruses that cause AIDS.
Human immunodeficiency virus 2
HIV-2 can also progress to AIDS, but its natural history and antiretroviral susceptibility differ from HIV-1.
Human immunodeficiency virus 2 NCBITaxon:11709 NCBI Taxonomy (NCBITaxon)
Show evidence (2 references)
PMID:22229120 SUPPORT Other
"Acquired immunodeficiency syndrome (AIDS) of humans is caused by two lentiviruses, human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2)."
This review identifies HIV-2 as one of the two human lentiviruses that cause AIDS.
PMID:36982978 SUPPORT Other
"The course of HIV-2 infection is longer compared to HIV-1 infection, but without effective antiretroviral therapy (ART), a substantial proportion of infected patients will progress to AIDS and die."
This supports progression of untreated HIV-2 infection to AIDS.
🔀

Differential Diagnoses

3

Conditions with similar clinical presentations that must be differentiated from Acquired Immunodeficiency Syndrome:

HIV Infection Without AIDS
Overlapping Features Confirmed HIV infection is broader than AIDS. In U.S. CDC surveillance, early infection can be stage 0, other cases can be stage 1, 2, or unknown, and AIDS is stage 3.
Distinguishing Features
  • Confirmed HIV infection alone does not establish AIDS.
  • Apply the surveillance framework's stage rules rather than inferring AIDS from HIV positivity alone.
Show evidence (1 reference)
PMID:24717910 SUPPORT Other
"A confirmed case can be classified in one of five HIV infection stages (0, 1, 2, 3, or unknown); early infection, recognized by a negative HIV test within 6 months of HIV diagnosis, is classified as stage 0, and acquired immunodeficiency syndrome (AIDS) is classified as stage 3."
This explicitly distinguishes AIDS/stage 3 from other stages of confirmed HIV infection.
Idiopathic CD4 Lymphocytopenia
Overlapping Features Rare CD4 lymphocytopenia syndrome described in HIV-negative patients.
Distinguishing Features
  • HIV testing is negative.
  • Other diseases and drugs remain differential considerations.
Show evidence (2 references)
PMID:16763460 SUPPORT Other
"Idiopathic CD4 lymphocytopenia is very rare. The clinical significance of low CD4 cell counts in HIV negative patients still awaits its systematic analysis."
This review describes the rarity of idiopathic CD4 lymphocytopenia in HIV-negative patients.
PMID:16763460 SUPPORT Other
"The differential diagnosis of this condition in adults comprises primarily HIV infection and less often other diseases or drugs."
This supports HIV, other diseases, and drugs as differential considerations.
Secondary Non-HIV CD4 Lymphocytopenia
Overlapping Features Infections, autoimmune disease, immunosuppressive treatment, and lymphoma can produce severe CD4 lymphocytopenia without HIV/AIDS.
Distinguishing Features
  • HIV testing is negative.
  • A non-HIV disease, infection, or medication explains the immune abnormality.
Show evidence (1 reference)
PMID:16763460 SUPPORT Other
"In adults, HIV is certainly the most common cause of CD4 lymphocytopenia, but other causes, such as infections, autoimmune diseases, immunosuppressive therapy, lymphoma and idiopathic forms need to be considered."
This review explicitly lists major non-HIV causes of CD4 lymphocytopenia.
{ }

Source YAML

click to show
name: Acquired Immunodeficiency Syndrome
creation_date: '2025-12-04T16:57:31Z'
synonyms:
- AIDS
- Acquired immune deficiency syndrome
description: >-
  Acquired immunodeficiency syndrome (AIDS) is the advanced clinical state of
  infection with human immunodeficiency virus type 1 (HIV-1) or type 2 (HIV-2),
  not a synonym for every HIV infection. In the U.S. CDC surveillance framework,
  AIDS is HIV infection stage 3; this numbering is framework-specific. Persistent
  viral replication, mucosal immune injury, chronic immune activation, and
  progressive failure of CD4 T-cell homeostasis produce severe cell-mediated
  immunodeficiency. Subject to the framework's stage-0 precedence rule, AIDS is
  classified by severe CD4 depletion or an AIDS-defining illness and is manifested
  by opportunistic infections, selected malignancies, and sometimes severe
  HIV-associated neurologic disease. Combination antiretroviral therapy suppresses
  viral replication and permits immune reconstitution but does not eradicate
  long-lived cellular reservoirs.
categories:
- Immunodeficiency Disorder
- Infectious Disease
disease_term:
  preferred_term: AIDS
  term:
    id: MONDO:0012268
    label: AIDS
definitions:
- name: CDC HIV stage-3 surveillance case definition
  definition_type: CASE_DEFINITION
  scope: United States public-health surveillance in people with confirmed HIV infection
  description: >-
    In the U.S. CDC framework, AIDS is HIV infection classified as stage 3. The
    surveillance framework uses severe CD4 depletion and AIDS-defining clinical
    conditions; it is intended for population surveillance and is not, by
    itself, a clinical decision rule for an individual patient.
  evidence:
  - reference: PMID:24717910
    reference_title: "Revised surveillance case definition for HIV infection--United States, 2014."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      A confirmed case can be classified in one of five HIV infection stages
      (0, 1, 2, 3, or unknown); early infection, recognized by a negative HIV
      test within 6 months of HIV diagnosis, is classified as stage 0, and
      acquired immunodeficiency syndrome (AIDS) is classified as stage 3.
    explanation: The CDC surveillance definition explicitly identifies AIDS as HIV infection stage 3.
  - reference: PMID:24717910
    reference_title: "Revised surveillance case definition for HIV infection--United States, 2014."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The surveillance case definition is intended primarily for monitoring the
      HIV infection burden and planning for prevention and care on a population
      level, not as a basis for clinical decisions for individual patients.
    explanation: This states the intended population-surveillance scope and its clinical-use limitation.
- name: Historical adult and adolescent CD4-depletion threshold
  definition_type: CASE_DEFINITION
  scope: 1993 U.S. CDC expanded AIDS surveillance definition for adolescents and adults
  description: >-
    The 1993 expanded U.S. CDC surveillance definition for adolescents and
    adults included HIV infection with a CD4 T-cell count below 200 cells per
    microliter or a CD4 percentage below 14 percent.
  evidence:
  - reference: PMID:8093740
    reference_title: From the Centers for Disease Control and Prevention. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Consistent with the 1993 revised classification system, CDC has also
      expanded the AIDS surveillance case definition to include all HIV-infected
      persons who have less than 200 CD4+ T-lymphocytes/microL, or a CD4+
      T-lymphocyte percentage of total lymphocytes of less than 14.
    explanation: The CDC publication gives the exact count and percentage thresholds.
infectious_agent:
- name: Human immunodeficiency virus 1
  description: HIV-1 is one of the two human lentiviruses that can cause AIDS.
  infectious_agent_term:
    preferred_term: Human immunodeficiency virus 1
    term:
      id: NCBITaxon:11676
      label: Human immunodeficiency virus 1
  evidence:
  - reference: PMID:22229120
    reference_title: Origins of HIV and the AIDS pandemic.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Acquired immunodeficiency syndrome (AIDS) of humans is caused by two
      lentiviruses, human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2).
    explanation: This review identifies HIV-1 as one of the two human lentiviruses that cause AIDS.
- name: Human immunodeficiency virus 2
  description: >-
    HIV-2 can also progress to AIDS, but its natural history and antiretroviral
    susceptibility differ from HIV-1.
  infectious_agent_term:
    preferred_term: Human immunodeficiency virus 2
    term:
      id: NCBITaxon:11709
      label: Human immunodeficiency virus 2
  evidence:
  - reference: PMID:22229120
    reference_title: Origins of HIV and the AIDS pandemic.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Acquired immunodeficiency syndrome (AIDS) of humans is caused by two
      lentiviruses, human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2).
    explanation: This review identifies HIV-2 as one of the two human lentiviruses that cause AIDS.
  - reference: PMID:36982978
    reference_title: "Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The course of HIV-2 infection is longer compared to HIV-1 infection, but
      without effective antiretroviral therapy (ART), a substantial proportion
      of infected patients will progress to AIDS and die.
    explanation: This supports progression of untreated HIV-2 infection to AIDS.
progression:
- phase: Onset
  notes: >-
    Progression from untreated HIV infection to overt AIDS is variable and can
    take many years. Acute HIV illness occurs much earlier and is not the onset
    of AIDS.
  evidence:
  - reference: PMID:23772614
    reference_title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Disease progression in untreated human immunodeficiency virus (HIV)
      infection can take many years, and it was originally hypothesized to be a
      consequence of slow, viral-mediated CD4(+) T-cell destruction.
    explanation: This review supports a long and variable untreated interval before overt immunodeficiency.
pathophysiology:
- name: Persistent HIV Infection and Replication
  description: >-
    HIV establishes ongoing infection in susceptible immune cells. Viral
    replication drives pathogenesis, while the resulting immunodeficiency
    reflects both direct viral effects and dysregulated host immune homeostasis.
  cell_types:
  - preferred_term: CD4-positive, alpha-beta T cell
    term:
      id: CL:0000624
      label: CD4-positive, alpha-beta T cell
  biological_processes:
  - preferred_term: viral process
    modifier: ABNORMAL
    term:
      id: GO:0016032
      label: viral process
  evidence:
  - reference: PMID:23772614
    reference_title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Thus, the onset of overt immune deficiency appears to be intimately linked
      with CD4(+) memory T-cell dynamics and reflects the complex interplay of
      direct viral cytopathogenicity and the indirect effects of persistent
      immune activation on CD4(+) memory T-cell proliferation, differentiation,
      and survival.
    explanation: This supports viral and host-homeostatic contributions to AIDS pathogenesis.
  downstream:
  - target: Early Mucosal CD4 T-Cell Loss and Gut Barrier Injury
    description: Early infection preferentially damages mucosal CD4 memory T-cell compartments.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:15955686
      reference_title: Viral and host factors in the pathogenesis of HIV infection.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        During acute infection, massive depletion of CD4+CCR5+ memory T cells
        within the mucosal-associated lymphoid tissue leads to major and
        potentially irreversible damage to CD4+ T-cell-mediated immune functions.
      explanation: This directly links early HIV infection to mucosal CD4 memory T-cell loss.
  - target: Abortive HIV Infection and Caspase-1 Pyroptosis
    description: >-
      In ex vivo human lymphoid tissue, abortive infection of quiescent CD4
      T cells triggers inflammatory caspase-1-mediated death.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:24356306
      reference_title: Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        The remaining over 95% of quiescent lymphoid CD4 T cells die by
        caspase-1-mediated pyroptosis triggered by abortive viral infection.
      explanation: The ex vivo study directly links abortive HIV infection to caspase-1 pyroptosis.
  - target: CNS HIV Infection and Neuroinflammation
    description: HIV can enter the CNS and initiate local inflammatory and neurotoxic processes.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Trafficking of infected immune cells into the central nervous system
    evidence:
    - reference: PMID:25604237
      reference_title: "Neuropathogenesis of HIV: from initial neuroinvasion to HIV-associated neurocognitive disorder (HAND)."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The well-accepted “Trojan horse” hypothesis suggests that the virus
        enters mainly through CD4 T lymphocytes or possibly monocytes during
        routine surveillance, only to go on infecting local cells of the CNS
        (16, 17).
      explanation: This review specifically supports immune-cell trafficking as a route of HIV entry into the CNS.
  - target: Persistent Cellular HIV Reservoir
    description: >-
      Integrated, transcriptionally silent provirus establishes a cellular
      reservoir that is refractory to suppressive ART.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Proviral integration and establishment of latency in long-lived host cells
    evidence:
    - reference: PMID:29744964
      reference_title: Peering into the HIV reservoir.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The HIV cellular reservoir comprises cells with HIV-DNA integrated into
        their genome, but trancriptionally silent, making the virus refractory
        to cART and to the action of the immune system.
      explanation: This review directly supports an integrated, transcriptionally silent reservoir refractory to ART.
- name: Early Mucosal CD4 T-Cell Loss and Gut Barrier Injury
  description: >-
    Acute HIV infection causes marked depletion of mucosal CD4 memory T cells,
    persistent mucosal inflammation, and epithelial barrier injury.
  cell_types:
  - preferred_term: CD4-positive, alpha-beta T cell
    term:
      id: CL:0000624
      label: CD4-positive, alpha-beta T cell
  locations:
  - preferred_term: small intestine
    term:
      id: UBERON:0002108
      label: small intestine
  evidence:
  - reference: PMID:23297256
    reference_title: Microbial translocation in the pathogenesis of HIV infection and AIDS.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      In vivo studies demonstrated that HIV/SIV-associated microbial
      translocation results from a series of immunopathological events occurring
      at the GI mucosa: (i) early and severe mucosal CD4(+) depletion, (ii)
      mucosal immune hyperactivation/persistent inflammation; (iii) damage to
      the integrity of the intestinal epithelium with enterocyte apoptosis and
      tight junction disruption; and (iv) subverted the gut microbiome, with a
      predominance of opportunistic bacteria.
    explanation: This review describes the linked mucosal CD4 loss, inflammation, and epithelial injury.
  downstream:
  - target: Microbial Translocation and Chronic Immune Activation
    description: Barrier disruption permits microbial products to reach the circulation and sustain innate immune activation.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23297256
      reference_title: Microbial translocation in the pathogenesis of HIV infection and AIDS.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        In pathogenic simian immunodeficiency virus (SIV) and human
        immunodeficiency virus (HIV) infections, the translocation of microbial
        products from the gastrointestinal (GI) tract to portal and systemic
        circulation has been proposed as a major driver of the chronic immune
        activation that is associated with disease progression.
      explanation: The source supports the proposed link while explicitly retaining mechanistic uncertainty.
- name: Microbial Translocation and Chronic Immune Activation
  description: >-
    Microbial products crossing the damaged gut barrier contribute to persistent
    innate and adaptive immune activation during chronic HIV infection.
  biological_processes:
  - preferred_term: T cell activation
    modifier: INCREASED
    term:
      id: GO:0042110
      label: T cell activation
  evidence:
  - reference: PMID:23297256
    reference_title: Microbial translocation in the pathogenesis of HIV infection and AIDS.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      While the mechanisms by which microbial translocation causes immune
      activation remain controversial, a key pathogenic event appears to be
      innate immunity activation via Toll-like receptors and other pathogen
      recognition receptors.
    explanation: This supports a contributory innate-activation mechanism while preserving uncertainty.
  downstream:
  - target: Progressive CD4 T-Cell Depletion and Homeostatic Failure
    description: >-
      Persistent immune activation disrupts CD4 memory-cell proliferation,
      differentiation, survival, and regenerative homeostasis.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Dysregulated CD4 memory T-cell turnover and regeneration
    evidence:
    - reference: PMID:23772614
      reference_title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Thus, the onset of overt immune deficiency appears to be intimately linked
        with CD4(+) memory T-cell dynamics and reflects the complex interplay of
        direct viral cytopathogenicity and the indirect effects of persistent
        immune activation on CD4(+) memory T-cell proliferation, differentiation,
        and survival.
      explanation: This review directly supports chronic activation as an indirect driver of CD4 homeostatic failure.
- name: Abortive HIV Infection and Caspase-1 Pyroptosis
  description: >-
    In ex vivo human lymphoid aggregates, abortive HIV-1 infection of quiescent
    CD4 T cells activates caspase-1, causing inflammatory pyroptotic cell death.
    This is a contributory experimental mechanism, not a universal quantitative
    estimate for every person with AIDS.
  cell_types:
  - preferred_term: CD4-positive, alpha-beta T cell
    term:
      id: CL:0000624
      label: CD4-positive, alpha-beta T cell
  biological_processes:
  - preferred_term: pyroptotic inflammatory response
    modifier: INCREASED
    term:
      id: GO:0070269
      label: pyroptotic inflammatory response
  evidence:
  - reference: PMID:24356306
    reference_title: Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Pyroptosis corresponds to an intensely inflammatory form of programmed
      cell death in which cytoplasmic contents and pro-inflammatory cytokines,
      including IL-1β, are released.
    explanation: The ex vivo study characterizes the inflammatory cell-death mechanism.
  downstream:
  - target: Progressive CD4 T-Cell Depletion and Homeostatic Failure
    description: Pyroptotic death of abortively infected lymphoid CD4 T cells contributes to the depleted CD4 pool.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:24356306
      reference_title: Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: >-
        The remaining over 95% of quiescent lymphoid CD4 T cells die by
        caspase-1-mediated pyroptosis triggered by abortive viral infection.
      explanation: This directly supports pyroptosis-mediated CD4 loss in the ex vivo lymphoid-tissue system.
- name: Progressive CD4 T-Cell Depletion and Homeostatic Failure
  description: >-
    Direct viral effects and chronic immune activation eventually overwhelm
    CD4 memory T-cell regeneration, lowering critical effector populations.
  cell_types:
  - preferred_term: CD4-positive, alpha-beta T cell
    term:
      id: CL:0000624
      label: CD4-positive, alpha-beta T cell
  evidence:
  - reference: PMID:23772614
    reference_title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Ultimately, CD4(+) memory T-cell homeostasis fails and critical effector
      populations decline below the level necessary to prevent OI.
    explanation: This supports progressive failure of CD4 homeostasis and loss of protective effector cells.
  downstream:
  - target: Severe Cell-Mediated Immunodeficiency
    description: Falling CD4 effector-cell numbers and function produce overt cellular immune failure.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23772614
      reference_title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The hallmark of acquired immunodeficiency syndrome (AIDS) pathogenesis is
        a progressive depletion of CD4(+) T-cell populations in close association
        with progressive impairment of cellular immunity and increasing
        susceptibility to opportunistic infections (OI).
      explanation: This directly connects progressive CD4 depletion with impaired cellular immunity.
- name: Severe Cell-Mediated Immunodeficiency
  description: >-
    Profound loss of CD4 T-cell number and function marks overt AIDS and
    undermines immune control of opportunistic pathogens and oncogenic viruses.
  cell_types:
  - preferred_term: CD4-positive, alpha-beta T cell
    term:
      id: CL:0000624
      label: CD4-positive, alpha-beta T cell
  evidence:
  - reference: PMID:23772614
    reference_title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Overall, these observations provide strong evidence that a profoundly
      impaired cellular immune response due to depletion of CD4+T cells and loss
      of CD4+T-cell function was the underlying cause of immunodeficiency present
      in these patients.
    explanation: This supports CD4 loss and dysfunction as the basis of severe cellular immunodeficiency.
  downstream:
  - target: Opportunistic Infection Susceptibility
    description: Loss of CD4-dependent host defense permits opportunistic pathogens to cause severe disease.
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23772614
      reference_title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The hallmark of acquired immunodeficiency syndrome (AIDS) pathogenesis is
        a progressive depletion of CD4(+) T-cell populations in close association
        with progressive impairment of cellular immunity and increasing
        susceptibility to opportunistic infections (OI).
      explanation: This directly links severe cellular immune impairment to opportunistic-infection susceptibility.
  - target: Loss of Oncogenic-Virus Immune Control
    description: Immunodeficiency permits oncogenic coinfections to escape immune control and promote tumors.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Failure of immune surveillance against HHV-8, Epstein-Barr virus, and oncogenic human papillomavirus
    evidence:
    - reference: PMID:12525676
      reference_title: AIDS-related malignancies.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        In acquired immunodeficiency due to the human immunodeficiency virus
        (HIV), HIV itself rarely directly causes cancer; rather, it provides the
        immunologic background against which other viruses can escape immune
        control and induce tumors.
      explanation: This review directly supports loss of immune control over oncogenic viruses as the cancer mechanism.
- name: Opportunistic Infection Susceptibility
  description: >-
    Severe cellular immunodeficiency permits AIDS-defining opportunistic
    infections; Pneumocystis pneumonia and esophageal candidiasis are
    representative manifestations rather than an exhaustive list.
  evidence:
  - reference: PMID:16182595
    reference_title: "Pneumocystis: immune recognition and evasion."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Pulmonary infection caused by the opportunistic fungal organism
      Pneumocystis continues to be a leading AIDS defining illness.
    explanation: This identifies Pneumocystis pneumonia as a leading AIDS-defining opportunistic illness.
  downstream:
  - target: Pneumocystis jirovecii Pneumonia
    description: Severe T-cell immunodeficiency permits pulmonary Pneumocystis infection.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Failure of coordinated innate and immune-mediated pulmonary fungal clearance
    evidence:
    - reference: PMID:16182595
      reference_title: "Pneumocystis: immune recognition and evasion."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Host defense against Pneumocystis involves a delicate, concerted balance
        between the inflammatory response and immune-mediated clearance.
      explanation: This supports failure of immune-mediated clearance as the link from immunodeficiency to Pneumocystis pneumonia.
  - target: Esophageal Candidiasis
    description: Severe cellular immune dysfunction permits invasive Candida infection of the esophagus.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Failure of mucosal antifungal host defense
    evidence:
    - reference: PMID:17944709
      reference_title: Invasive fungal infections among inpatients with acquired immune deficiency syndrome at a Chinese university hospital.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        IFIs included thrush, oesophageal candidiasis, fungal pneumonia,
        cryptococcosis, penicilliosis and fungaemia, 44.4% of IFIs occurred in
        the digestive tract, 71.8% of IFIs occurred in patients with
        CD4(+)T-lymphocyte counts <100 cells mm(-3).
      explanation: This cohort links esophageal candidiasis and other invasive fungal infections with severe CD4 depletion.
- name: Loss of Oncogenic-Virus Immune Control
  description: >-
    AIDS-associated immune dysfunction reduces surveillance of HHV-8,
    Epstein-Barr virus, and oncogenic human papillomavirus, enabling selected
    malignancies.
  evidence:
  - reference: PMID:12525676
    reference_title: AIDS-related malignancies.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Immunodeficiency alters the risk of cancer. Specific types of immune
      dysfunction are associated with different tumor risks, but most tumors are
      related to oncogenic viruses.
    explanation: This supports oncogenic-virus-associated malignancy in the immunodeficient state.
  downstream:
  - target: Kaposi Sarcoma
    description: Kaposi sarcoma-associated herpesvirus is implicated in Kaposi sarcoma development.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - HHV-8-associated Kaposi sarcoma development
    evidence:
    - reference: PMID:8876905
      reference_title: Oncological problems in AIDS--a review of the clinical features and management.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Kaposi's sarcoma-associated herpes virus is implicated in the
        development of Kaposi's sarcoma, Epstein-Barr virus in systemic
        non-Hodgkin's lymphoma as well as primary central nervous system
        lymphoma and human papilloma virus in invasive cervical cancer.
      explanation: This directly supports the association between HHV-8 and Kaposi sarcoma.
  - target: AIDS-Related Non-Hodgkin Lymphoma
    description: Epstein-Barr virus is implicated in systemic and primary-CNS AIDS-related lymphomas.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Epstein-Barr virus association with systemic and primary-CNS lymphoma
    evidence:
    - reference: PMID:8876905
      reference_title: Oncological problems in AIDS--a review of the clinical features and management.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Kaposi's sarcoma-associated herpes virus is implicated in the
        development of Kaposi's sarcoma, Epstein-Barr virus in systemic
        non-Hodgkin's lymphoma as well as primary central nervous system
        lymphoma and human papilloma virus in invasive cervical cancer.
      explanation: This directly supports the association between EBV and systemic or primary-CNS lymphoma.
  - target: Invasive Cervical Cancer
    description: Oncogenic human papillomavirus is implicated in invasive cervical cancer.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Human papillomavirus association with invasive cervical cancer
    evidence:
    - reference: PMID:8876905
      reference_title: Oncological problems in AIDS--a review of the clinical features and management.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Kaposi's sarcoma-associated herpes virus is implicated in the
        development of Kaposi's sarcoma, Epstein-Barr virus in systemic
        non-Hodgkin's lymphoma as well as primary central nervous system
        lymphoma and human papilloma virus in invasive cervical cancer.
      explanation: This directly supports the association between HPV and invasive cervical cancer.
- name: CNS HIV Infection and Neuroinflammation
  description: >-
    HIV can establish compartmentalized infection in CNS macrophage-lineage
    cells. Local immune activation, neuroinflammation, and neurotoxicity can
    contribute to severe HIV-associated cognitive disease.
  cell_types:
  - preferred_term: microglial cell
    term:
      id: CL:0000129
      label: microglial cell
  locations:
  - preferred_term: brain
    term:
      id: UBERON:0000955
      label: brain
  evidence:
  - reference: PMID:25604237
    reference_title: "Neuropathogenesis of HIV: from initial neuroinvasion to HIV-associated neurocognitive disorder (HAND)."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Recent work suggests that the stage for HIV neuropathogenesis may be set
      with initial viral entry into the CNS, followed by initiation of
      pathogenetic processes including neuroinflammation and neurotoxicity, and
      establishment of local, compartmentalized HIV replication that may reflect
      a tissue reservoir for HIV.
    explanation: This review supports CNS infection, neuroinflammation, and neurotoxicity.
  downstream:
  - target: AIDS Dementia Complex
    description: Severe CNS HIV disease can culminate in HIV-associated dementia/AIDS dementia complex.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Macrophage and microglial activation, inflammatory mediator release, and neuronal dysfunction
    evidence:
    - reference: PMID:25604237
      reference_title: "Neuropathogenesis of HIV: from initial neuroinvasion to HIV-associated neurocognitive disorder (HAND)."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Early in the HIV epidemic, a large proportion of the neurological
        manifestations of HIV presented as opportunistic CNS infections,
        including toxoplasmosis and progressive multifocal leukoencephalopathy
        (1). By 1987, the non-specific “subacute encephalitis” that widely
        affected patients with HIV was identified as the AIDS dementia complex
        (ADC, now termed HIV-associated dementia, or HAD), and was recognized as
        a manifestation of HIV itself rather than that of an alternate infection
        (2).
      explanation: This supports AIDS dementia as an HIV manifestation while the exact mechanistic route remains multifactorial.
- name: Persistent Cellular HIV Reservoir
  description: >-
    Resting CD4 memory T cells and other cellular compartments can retain
    integrated provirus during suppressive ART, preventing eradication and
    enabling renewed infection if therapy stops.
  cell_types:
  - preferred_term: CD4-positive, alpha-beta T cell
    term:
      id: CL:0000624
      label: CD4-positive, alpha-beta T cell
  evidence:
  - reference: PMID:29744964
    reference_title: Peering into the HIV reservoir.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The HIV cellular reservoir comprises cells with HIV-DNA integrated into
      their genome, but trancriptionally silent, making the virus refractory to
      cART and to the action of the immune system.
    explanation: This directly supports integrated, transcriptionally silent HIV persisting despite ART.
  - reference: PMID:29744964
    reference_title: Peering into the HIV reservoir.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Numerous reports have described that the main HIV cellular reservoir is
      composed of resting CD4+ T-cells16–18. Importantly, replication-competent
      provirus from the latent reservoir is capable of reigniting new rounds of
      infection if therapy is interrupted4,5.
    explanation: This supports resting CD4 T cells as a major reservoir and renewed infection after ART interruption.
  - reference: PMID:37317962
    reference_title: Brain microglia serve as a persistent HIV reservoir despite durable antiretroviral therapy.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Outgrowth virus from parietal cortex MG in an individual with HIV
      productively infected both MG and PBMCs.
    explanation: Human rapid-autopsy tissue with ex vivo viral outgrowth supports replication-competent HIV in brain microglia.
phenotypes:
- name: Pneumocystis jirovecii Pneumonia
  category: Respiratory
  description: Pneumocystis jirovecii pneumonia is a representative AIDS-defining opportunistic infection.
  diagnostic: true
  phenotype_term:
    preferred_term: Pneumocystis jirovecii pneumonia
    term:
      id: HP:0020102
      label: Pneumocystis jirovecii pneumonia
  evidence:
  - reference: PMID:16182595
    reference_title: "Pneumocystis: immune recognition and evasion."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Pulmonary infection caused by the opportunistic fungal organism
      Pneumocystis continues to be a leading AIDS defining illness.
    explanation: This identifies Pneumocystis pneumonia as an AIDS-defining illness.
- name: Esophageal Candidiasis
  category: Gastrointestinal
  description: Esophageal candidiasis is a representative AIDS-defining opportunistic infection.
  diagnostic: true
  evidence:
  - reference: PMID:18366449
    reference_title: Causes of the first AIDS-defining illness and subsequent survival before and after the advent of combined antiretroviral therapy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The three most frequent initial ADIs were Pneumocystis carinii (jirovecii)
      pneumonia (PCP) (15.6%), oesophageal candidiasis (14.3%) and Kaposi's
      sarcoma (13.9%) in the pre-cART period.
    explanation: This cohort explicitly identifies esophageal candidiasis as an initial AIDS-defining illness.
- name: Kaposi Sarcoma
  category: Neoplasm
  description: Kaposi sarcoma is an HHV-8-associated AIDS-defining malignancy.
  diagnostic: true
  phenotype_term:
    preferred_term: Kaposi's sarcoma
    term:
      id: HP:0100726
      label: Kaposi's sarcoma
  evidence:
  - reference: PMID:18366449
    reference_title: Causes of the first AIDS-defining illness and subsequent survival before and after the advent of combined antiretroviral therapy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The three most frequent initial ADIs were Pneumocystis carinii (jirovecii)
      pneumonia (PCP) (15.6%), oesophageal candidiasis (14.3%) and Kaposi's
      sarcoma (13.9%) in the pre-cART period.
    explanation: This cohort identifies Kaposi sarcoma as an initial AIDS-defining illness.
- name: AIDS-Related Non-Hodgkin Lymphoma
  category: Neoplasm
  description: >-
    Systemic and primary-CNS non-Hodgkin lymphomas are representative
    AIDS-associated malignancies.
  evidence:
  - reference: PMID:8876905
    reference_title: Oncological problems in AIDS--a review of the clinical features and management.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      They include Kaposi's sarcoma, systemic non-Hodgkin's lymphoma, primary
      central nervous system lymphoma and invasive cervical cancer.
    explanation: This review identifies systemic and CNS non-Hodgkin lymphomas among AIDS-associated malignancies.
- name: Invasive Cervical Cancer
  category: Neoplasm
  description: Invasive cervical cancer is an HPV-associated AIDS-defining condition.
  diagnostic: true
  evidence:
  - reference: PMID:8093740
    reference_title: From the Centers for Disease Control and Prevention. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      This expansion includes the addition of three clinical
      conditions--pulmonary tuberculosis, recurrent pneumonia, and invasive
      cervical cancer--and retains the 23 clinical conditions in the AIDS
      surveillance case definition published in 1987; it is to be used by all
      states for AIDS case reporting effective immediately.
    explanation: The expanded CDC surveillance definition explicitly added invasive cervical cancer.
- name: AIDS Dementia Complex
  category: Neurologic
  description: >-
    AIDS dementia complex, now commonly called HIV-associated dementia, is the
    severe neurocognitive manifestation linked to advanced HIV disease.
  evidence:
  - reference: PMID:25604237
    reference_title: "Neuropathogenesis of HIV: from initial neuroinvasion to HIV-associated neurocognitive disorder (HAND)."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      By 1987, the non-specific “subacute encephalitis” that widely affected
      patients with HIV was identified as the AIDS dementia complex (ADC, now
      termed HIV-associated dementia, or HAD), and was recognized as a
      manifestation of HIV itself rather than that of an alternate infection
      (2).
    explanation: This identifies AIDS dementia complex/HIV-associated dementia as a direct HIV manifestation.
biochemical:
- name: CD4 T-Cell Count
  biomarker_term:
    preferred_term: CD4 Expressing T Cell Count
    term:
      id: NCIT:C74608
      label: CD4 Expressing T Cell Count
  presence: Decreased
  context: >-
    Absolute count and percentage are U.S. CDC surveillance-stage measures with
    age-specific thresholds. The count takes precedence, and percentage is used
    only when the count is missing. Stage 0 and a qualifying opportunistic illness
    can take precedence over the CD4 table. Values can rise after ART and must be
    interpreted with clinical history.
  readouts:
  - target: Severe Cell-Mediated Immunodeficiency
    relationship: READOUT_OF
    direction: THRESHOLD_DEPENDENT
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      For a person aged 6 years or older who does not meet stage-0 criteria, a
      CD4 count below 200 cells per microliter indicates U.S. CDC surveillance
      stage 3; a CD4 percentage below 14 percent is used only when the count is
      missing. Children younger than 6 years have age-specific stage-3 cutoffs.
    evidence:
    - reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
      reference_title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        TABLE. HIV infection stage* based on age-specific CD4+ T-lymphocyte
        count or CD4+ T-lymphocyte percentage of total lymphocytes
        Stage
        Age on date of CD4+ T-lymphocyte test
        <1 yr 1–5 yrs ≥6 yrs
        Cells/µL % Cells/µL % Cells/µL %
        1 ≥1,500 ≥34 ≥1,000 ≥30 ≥500 ≥26
        2 750–1,499 26–33 500–999 22–29 200–499 14–25
        3 <750 <26 <500 <22 <200 <14
      explanation: The official table supplies age-specific stage-3 CD4 count and percentage thresholds.
    - reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
      reference_title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The stage is based primarily on the CD4+ T-lymphocyte count; the CD4+
        T-lymphocyte count takes precedence over the CD4 T-lymphocyte percentage,
        and the percentage is considered only if the count is missing.
      explanation: This establishes count precedence and percentage use only when the count is missing.
    - reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
      reference_title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        if the criteria for stage 0 are met, the stage is 0 regardless of
        criteria for other stages (CD4 T-lymphocyte test results and
        opportunistic illness diagnoses)
      explanation: This establishes stage-0 precedence over CD4 results and stage-3-defining illnesses.
  evidence:
  - reference: PMID:8093740
    reference_title: From the Centers for Disease Control and Prevention. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The Centers for Disease Control and Prevention (CDC) has revised the
      classification system for HIV infection to emphasize the clinical
      importance of the CD4+ T-lymphocyte count in the categorization of
      HIV-related clinical conditions.
    explanation: This establishes CD4 count as a central HIV-stage classification biomarker.
- name: HIV Viral Load
  biomarker_term:
    preferred_term: HIV Viral Load Measurement
    term:
      id: NCIT:C92544
      label: HIV Viral Load Measurement
  presence: Variable
  context: >-
    Plasma HIV RNA monitors viral replication and treatment response; values can
    become suppressed with effective ART.
  readouts:
  - target: Persistent HIV Infection and Replication
    relationship: PHARMACODYNAMIC_MARKER_OF
    direction: POSITIVE
    endpoint_context: PHARMACODYNAMIC
    interpretation: Falling HIV RNA indicates pharmacodynamic suppression of viral replication by ART.
    evidence:
    - reference: PMID:36308326
      reference_title: "Mortality and immunovirological outcomes in patients with advanced HIV disease on their first antiretroviral treatment: differential impact of antiretroviral regimens."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Patients who started an InSTI achieved viral suppression and CD4+ T cell
        count above 350 cells/mm3significantly earlier.
      explanation: The advanced-HIV cohort uses viral suppression as a treatment-response readout.
  evidence:
  - reference: PMID:36308326
    reference_title: "Mortality and immunovirological outcomes in patients with advanced HIV disease on their first antiretroviral treatment: differential impact of antiretroviral regimens."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The main outcomes were mortality, virological effectiveness (percentage of
      patients with viral load of ≤50 copies/mL) and immune restoration
      (percentage of patients with CD4+ T cell count above 350 cells/mm3).
    explanation: This supports viral load as a virologic-treatment outcome in advanced HIV disease.
diagnosis:
- name: Confirm HIV Infection and Differentiate HIV-1 from HIV-2
  description: >-
    AIDS classification first requires established HIV infection. Contemporary
    multitest algorithms include differentiation of HIV-1 and HIV-2.
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: NCIT:C18020
      label: Diagnostic Procedure
  results: Laboratory evidence confirms HIV infection and, where possible, distinguishes HIV-1 from HIV-2.
  evidence:
  - reference: PMID:24717910
    reference_title: "Revised surveillance case definition for HIV infection--United States, 2014."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Laboratory criteria for defining a confirmed case now accommodate new
      multitest algorithms, including criteria for differentiating between HIV-1
      and HIV-2 infection and for recognizing early HIV infection.
    explanation: This supports confirmation and type differentiation before stage classification.
- name: U.S. CDC CD4 Surveillance-Stage Classification
  description: >-
    After HIV confirmation, apply the age-specific U.S. CDC surveillance table.
    Absolute CD4 count takes precedence; use percentage only if the count is
    missing, and apply stage-0 precedence before later-stage criteria.
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: NCIT:C18020
      label: Diagnostic Procedure
  results: >-
    At age 6 years or older, count below 200 cells per microliter indicates stage
    3 when stage-0 criteria do not apply; percentage below 14 percent is used only
    when count is missing. Children younger than 6 years have higher age-specific
    stage-3 cutoffs.
  evidence:
  - reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
    reference_title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      TABLE. HIV infection stage* based on age-specific CD4+ T-lymphocyte
      count or CD4+ T-lymphocyte percentage of total lymphocytes
      Stage
      Age on date of CD4+ T-lymphocyte test
      <1 yr 1–5 yrs ≥6 yrs
      Cells/µL % Cells/µL % Cells/µL %
      1 ≥1,500 ≥34 ≥1,000 ≥30 ≥500 ≥26
      2 750–1,499 26–33 500–999 22–29 200–499 14–25
      3 <750 <26 <500 <22 <200 <14
    explanation: The official table supplies age-specific stage-3 CD4 count and percentage thresholds.
  - reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
    reference_title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The stage is based primarily on the CD4+ T-lymphocyte count; the CD4+
      T-lymphocyte count takes precedence over the CD4 T-lymphocyte percentage,
      and the percentage is considered only if the count is missing.
    explanation: This establishes count precedence and percentage use only when the count is missing.
  - reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
    reference_title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      if the criteria for stage 0 are met, the stage is 0 regardless of
      criteria for other stages (CD4 T-lymphocyte test results and
      opportunistic illness diagnoses)
    explanation: This establishes stage-0 precedence before later-stage classification.
- name: Assessment for AIDS-Defining Illnesses
  description: >-
    In the U.S. CDC surveillance framework, evaluate confirmed HIV infection for
    stage-3 clinical conditions, including specified opportunistic infections
    and malignancies. This clinical route is distinct from diagnosing HIV
    infection itself.
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: NCIT:C18020
      label: Diagnostic Procedure
  results: >-
    When stage-0 criteria are not met, a qualifying AIDS-defining illness
    establishes stage 3 regardless of the CD4 result.
  evidence:
  - reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
    reference_title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      If a stage-3–defining opportunistic illness has been diagnosed, then the
      stage is 3 regardless of CD4 T-lymphocyte test results, unless the criteria
      described below for stage 0 are met.
    explanation: This directly states the opportunistic-illness rule and its stage-0 exception.
  - reference: PMID:18366449
    reference_title: Causes of the first AIDS-defining illness and subsequent survival before and after the advent of combined antiretroviral therapy.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The three most frequent initial ADIs were Pneumocystis carinii (jirovecii)
      pneumonia (PCP) (15.6%), oesophageal candidiasis (14.3%) and Kaposi's
      sarcoma (13.9%) in the pre-cART period.
    explanation: This provides representative clinical AIDS-defining illnesses.
treatments:
- name: Combination Antiretroviral Therapy
  action_category: THERAPEUTIC
  description: >-
    Individualized combination ART suppresses HIV replication. Contemporary
    initial regimens for most adults use an integrase strand-transfer inhibitor
    with nucleoside or nucleotide reverse-transcriptase inhibitor components;
    regimen selection must account for clinical context, resistance, interactions,
    and HIV type.
  treatment_term:
    preferred_term: Antiretroviral Therapy
    term:
      id: NCIT:C94631
      label: Antiretroviral Therapy
  target_mechanisms:
  - target: Persistent HIV Infection and Replication
    treatment_effect: INHIBITS
    description: Combination ART suppresses active viral replication.
    evidence:
    - reference: PMID:36308326
      reference_title: "Mortality and immunovirological outcomes in patients with advanced HIV disease on their first antiretroviral treatment: differential impact of antiretroviral regimens."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Patients who started an InSTI achieved viral suppression and CD4+ T cell
        count above 350 cells/mm3significantly earlier.
      explanation: This advanced-HIV cohort directly supports antiretroviral-regimen suppression of active HIV replication.
  - target: Severe Cell-Mediated Immunodeficiency
    treatment_effect: RESTORES
    description: Viral suppression permits partial CD4 immune reconstitution and reduces opportunistic disease.
    evidence:
    - reference: PMID:11424971
      reference_title: Immune restoration and CD4+ T-cell function with antiretroviral therapies.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Suppression of HIV-1 replication results in both laboratory and clinical
        evidence of immune restoration.
      explanation: This review supports immune restoration after suppressive ART.
  evidence:
  - reference: PMID:39616604
    reference_title: "Antiretroviral Drugs for Treatment and Prevention of HIV in Adults: 2024 Recommendations of the International Antiviral Society-USA Panel."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      For most people with HIV, initial regimens composed of an integrase strand
      transfer inhibitor (InSTI), specifically bictegravir or dolutegravir, with
      2 (and in some cases 1) nucleoside or nucleotide reverse transcriptase
      inhibitors are recommended.
    explanation: This provides current initial-regimen guidance for most adults with HIV.
  - reference: PMID:36308326
    reference_title: "Mortality and immunovirological outcomes in patients with advanced HIV disease on their first antiretroviral treatment: differential impact of antiretroviral regimens."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In this large real-life prospective cohort study, a significant lower
      mortality, earlier viral suppression and earlier immune reconstitution
      were observed among patients with advanced HIV disease treated with InSTIs.
    explanation: This advanced-HIV cohort supports viral suppression, immune reconstitution, and clinical benefit.
  - reference: PMID:36982978
    reference_title: "Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Antiretroviral drugs in clinical use were designed for HIV-1 and,
      unfortunately, some do not work as well, or do not work at all, for HIV-2.
    explanation: This supports HIV type-specific antiretroviral regimen selection.
  notes: >-
    Some antiretrovirals active against HIV-1 are ineffective against HIV-2;
    HIV-2 treatment requires type-appropriate expert regimen selection.
- name: Context-Specific Opportunistic-Infection Prophylaxis
  action_category: THERAPEUTIC
  description: >-
    Antimicrobial prophylaxis can reduce selected opportunistic infections in
    people with advanced immunosuppression. The agent, CD4 threshold, pathogen,
    geography, screening results, interactions, and concurrent ART determine the
    appropriate regimen; there is no single universal prophylaxis bundle.
  treatment_term:
    preferred_term: preventative therapy
    term:
      id: NCIT:C15843
      label: Preventive Intervention
  target_mechanisms:
  - target: Opportunistic Infection Susceptibility
    treatment_effect: BYPASSES
    description: >-
      Prophylactic antimicrobials reduce selected infections during advanced
      immunosuppression while ART is initiated.
    evidence:
    - reference: PMID:28723333
      reference_title: Enhanced Prophylaxis plus Antiretroviral Therapy for Advanced HIV Infection in Africa.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Patients in the enhanced-prophylaxis group had significantly lower rates
        of tuberculosis (P=0.02), cryptococcal infection (P=0.01), oral or
        esophageal candidiasis (P=0.02), death of unknown cause (P=0.03), and new
        hospitalization (P=0.03).
      explanation: The trial supports clinical prevention; BYPASSES denotes prevention despite, rather than correction of, the immune deficit.
  evidence:
  - reference: PMID:28723333
    reference_title: Enhanced Prophylaxis plus Antiretroviral Therapy for Advanced HIV Infection in Africa.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Patients in the enhanced-prophylaxis group had significantly lower rates
      of tuberculosis (P=0.02), cryptococcal infection (P=0.01), oral or
      esophageal candidiasis (P=0.02), death of unknown cause (P=0.03), and new
      hospitalization (P=0.03).
    explanation: The trial documents condition-specific benefits of the evaluated prophylaxis bundle.
  context: >-
    The cited REALITY trial enrolled ART-naive participants in Uganda, Zimbabwe,
    Malawi, and Kenya with CD4 counts below 100 cells per cubic millimeter.
differential_diagnoses:
- name: HIV Infection Without AIDS
  description: >-
    Confirmed HIV infection is broader than AIDS. In U.S. CDC surveillance,
    early infection can be stage 0, other cases can be stage 1, 2, or unknown,
    and AIDS is stage 3.
  distinguishing_features:
  - Confirmed HIV infection alone does not establish AIDS.
  - Apply the surveillance framework's stage rules rather than inferring AIDS from HIV positivity alone.
  evidence:
  - reference: PMID:24717910
    reference_title: "Revised surveillance case definition for HIV infection--United States, 2014."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      A confirmed case can be classified in one of five HIV infection stages
      (0, 1, 2, 3, or unknown); early infection, recognized by a negative HIV
      test within 6 months of HIV diagnosis, is classified as stage 0, and
      acquired immunodeficiency syndrome (AIDS) is classified as stage 3.
    explanation: This explicitly distinguishes AIDS/stage 3 from other stages of confirmed HIV infection.
- name: Idiopathic CD4 Lymphocytopenia
  description: Rare CD4 lymphocytopenia syndrome described in HIV-negative patients.
  distinguishing_features:
  - HIV testing is negative.
  - Other diseases and drugs remain differential considerations.
  evidence:
  - reference: PMID:16763460
    reference_title: Idiopathic CD4 lymphocytopenia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Idiopathic CD4 lymphocytopenia is very rare. The clinical significance of
      low CD4 cell counts in HIV negative patients still awaits its systematic
      analysis.
    explanation: This review describes the rarity of idiopathic CD4 lymphocytopenia in HIV-negative patients.
  - reference: PMID:16763460
    reference_title: Idiopathic CD4 lymphocytopenia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The differential diagnosis of this condition in adults comprises primarily
      HIV infection and less often other diseases or drugs.
    explanation: This supports HIV, other diseases, and drugs as differential considerations.
- name: Secondary Non-HIV CD4 Lymphocytopenia
  description: >-
    Infections, autoimmune disease, immunosuppressive treatment, and lymphoma
    can produce severe CD4 lymphocytopenia without HIV/AIDS.
  distinguishing_features:
  - HIV testing is negative.
  - A non-HIV disease, infection, or medication explains the immune abnormality.
  evidence:
  - reference: PMID:16763460
    reference_title: Idiopathic CD4 lymphocytopenia.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      In adults, HIV is certainly the most common cause of CD4 lymphocytopenia,
      but other causes, such as infections, autoimmune diseases,
      immunosuppressive therapy, lymphoma and idiopathic forms need to be
      considered.
    explanation: This review explicitly lists major non-HIV causes of CD4 lymphocytopenia.
notes: >-
  AIDS is an advanced state caused by HIV infection; it is not transmitted
  independently, so HIV transmission routes are not duplicated as AIDS
  transmission records. No global prevalence value is asserted because HIV
  prevalence is not interchangeable with the prevalence of AIDS.
  The listed AIDS-defining illnesses are representative rather than exhaustive,
  and treatment of each diagnosed infection or malignancy remains
  condition-specific. Tangential drug-design models and incorrectly annotated
  protein structures were removed because they did not model or depict the
  claimed AIDS-specific mechanisms.
datasets: []
references:
- reference: PMID:11424971
  title: Immune restoration and CD4+ T-cell function with antiretroviral therapies.
- reference: PMID:12525676
  title: AIDS-related malignancies.
- reference: PMID:15955686
  title: Viral and host factors in the pathogenesis of HIV infection.
- reference: PMID:16182595
  title: "Pneumocystis: immune recognition and evasion."
- reference: PMID:16763460
  title: Idiopathic CD4 lymphocytopenia.
- reference: PMID:17944709
  title: Invasive fungal infections among inpatients with acquired immune deficiency syndrome at a Chinese university hospital.
- reference: PMID:18366449
  title: Causes of the first AIDS-defining illness and subsequent survival before and after the advent of combined antiretroviral therapy.
- reference: PMID:22229120
  title: Origins of HIV and the AIDS pandemic.
- reference: PMID:23297256
  title: Microbial translocation in the pathogenesis of HIV infection and AIDS.
- reference: PMID:23772614
  title: "CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure."
- reference: PMID:24356306
  title: Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection.
- reference: PMID:24717910
  title: "Revised surveillance case definition for HIV infection--United States, 2014."
- reference: PMID:25604237
  title: "Neuropathogenesis of HIV: from initial neuroinvasion to HIV-associated neurocognitive disorder (HAND)."
- reference: PMID:28723333
  title: Enhanced Prophylaxis plus Antiretroviral Therapy for Advanced HIV Infection in Africa.
- reference: PMID:29744964
  title: Peering into the HIV reservoir.
- reference: PMID:36308326
  title: "Mortality and immunovirological outcomes in patients with advanced HIV disease on their first antiretroviral treatment: differential impact of antiretroviral regimens."
- reference: PMID:36982978
  title: "Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds."
- reference: PMID:37317962
  title: Brain microglia serve as a persistent HIV reservoir despite durable antiretroviral therapy.
- reference: PMID:39616604
  title: "Antiretroviral Drugs for Treatment and Prevention of HIV in Adults: 2024 Recommendations of the International Antiviral Society-USA Panel."
- reference: PMID:8093740
  title: From the Centers for Disease Control and Prevention. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults.
- reference: PMID:8876905
  title: Oncological problems in AIDS--a review of the clinical features and management.
- reference: url:https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
  title: "https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf"
📚

References & Deep Research

References

22
Immune restoration and CD4+ T-cell function with antiretroviral therapies.
No top-level findings curated for this source.
AIDS-related malignancies.
No top-level findings curated for this source.
Viral and host factors in the pathogenesis of HIV infection.
No top-level findings curated for this source.
Pneumocystis: immune recognition and evasion.
No top-level findings curated for this source.
Idiopathic CD4 lymphocytopenia.
No top-level findings curated for this source.
Invasive fungal infections among inpatients with acquired immune deficiency syndrome at a Chinese university hospital.
No top-level findings curated for this source.
Causes of the first AIDS-defining illness and subsequent survival before and after the advent of combined antiretroviral therapy.
No top-level findings curated for this source.
Origins of HIV and the AIDS pandemic.
No top-level findings curated for this source.
Microbial translocation in the pathogenesis of HIV infection and AIDS.
No top-level findings curated for this source.
CD4(+) T-cell depletion in HIV infection: mechanisms of immunological failure.
No top-level findings curated for this source.
Cell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection.
No top-level findings curated for this source.
Revised surveillance case definition for HIV infection--United States, 2014.
No top-level findings curated for this source.
Neuropathogenesis of HIV: from initial neuroinvasion to HIV-associated neurocognitive disorder (HAND).
No top-level findings curated for this source.
Enhanced Prophylaxis plus Antiretroviral Therapy for Advanced HIV Infection in Africa.
No top-level findings curated for this source.
Peering into the HIV reservoir.
No top-level findings curated for this source.
Mortality and immunovirological outcomes in patients with advanced HIV disease on their first antiretroviral treatment: differential impact of antiretroviral regimens.
No top-level findings curated for this source.
Antiretroviral Treatment of HIV-2 Infection: Available Drugs, Resistance Pathways, and Promising New Compounds.
No top-level findings curated for this source.
Brain microglia serve as a persistent HIV reservoir despite durable antiretroviral therapy.
No top-level findings curated for this source.
Antiretroviral Drugs for Treatment and Prevention of HIV in Adults: 2024 Recommendations of the International Antiviral Society-USA Panel.
No top-level findings curated for this source.
From the Centers for Disease Control and Prevention. 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults.
No top-level findings curated for this source.
Oncological problems in AIDS--a review of the clinical features and management.
No top-level findings curated for this source.
https://www.cdc.gov/mmwr/pdf/rr/rr6303.pdf
No top-level findings curated for this source.

Deep Research

2
Disorder

Disorder

  • Name: Acquired Immunodeficiency Syndrome
  • Category:
  • Existing deep-research providers: falcon
  • Existing evidence reference count in YAML: 103

Key Pathophysiology Nodes

  • CD4 T-cell Depletion
  • Immune System Collapse
  • Opportunistic Infections
  • CNS Reservoir and Neuroinflammation
  • Host Restriction Factor Defense
  • AIDS-related Cancers
  • Deep research literature mapping

Citation Inventory (for evidence mapping)

  • DOI:10.1007/s40588-024-00234-9
  • DOI:10.1038/s41579-024-01010-8
  • DOI:10.1093/jmcb/mjae005
  • DOI:10.1097/cm9.0000000000003383
  • DOI:10.1097/id9.0000000000000152
  • DOI:10.1128/mbio.01909-24
  • DOI:10.1186/s12977-024-00641-2
  • DOI:10.1371/journal.pone.0308859
  • DOI:10.20411/pai.v9i1.693
  • DOI:10.3389/fimmu.2025.1650852
  • DOI:10.3390/v16081281
Falcon
Pathophysiology description (current understanding, 2023–2025 priorities)
Edison Scientific Literature 27 citations 2025-12-15T09:09:56.659376

Pathophysiology description (current understanding, 2023–2025 priorities) AIDS is the clinical end-stage of chronic HIV infection, driven by sustained viral replication, establishment of long-lived latent reservoirs, progressive immune dysfunction with CD4+ T-cell depletion, and chronic inflammation. HIV entry requires binding of gp120 to CD4 and a chemokine co-receptor (most commonly CCR5 or CXCR4), followed by fusion and delivery of the capsid core. Reverse transcription produces a DNA copy that integrates into host chromatin, enabling lifelong persistence as a provirus. Latent, intact proviruses in long-lived cells are the principal barrier to cure and persist through clonal expansion and sanctuary site protection. Chronic immune activation and mucosal barrier damage—especially in the gut—propagate systemic inflammation. Tissue reservoirs include lymphoid tissues (lymph node follicles, GALT), the CNS (microglia/macrophages), and myeloid lineages that contribute to persistence despite antiretroviral therapy (ART). Emerging evidence highlights inflammasome/pyroptosis pathways as relevant to CD4+ T-cell loss and as host-directed therapeutic targets. (moezpoor2024helporhinder pages 22-23, yildirir2024smacmimeticssensitize pages 24-31, lau2025hivandthe pages 1-2, armanitourret2024immunetargetingof pages 16-18, holloway2024inhibitionofcaspase pages 1-2, mohammadzadeh2025hivpersistencein pages 37-43, yildirir2024smacmimeticssensitize pages 191-196, calado2024decipheringthemechanisms pages 199-203)

Core pathophysiology 1) Viral entry, uncoating, reverse transcription - Entry: HIV uses CD4 with CCR5 or CXCR4 co-receptors to infect target cells; tropism differences reflect co-receptor usage and receptor density on T cells and myeloid cells, shaping early tissue targeting. Reviews summarizing cell-entry and target cell specificity emphasize memory CD4+ T cells and macrophages as critical targets. (Moezpoor & Stevenson 2024, Viruses; URL: https://doi.org/10.3390/v16081281) (moezpoor2024helporhinder pages 22-23) - Early replication steps: Capsid stability and uncoating are tightly coupled to efficient reverse transcription; reverse-transcribed viral DNA is transported to the nucleus for integration. Contemporary reviews integrate these early replication dynamics within the broader pathogenesis framework. (moezpoor2024helporhinder pages 22-23)

2) Integration, latency, and reservoirs - Latency: Integration into host chromatin creates a transcriptionally silent provirus; intact latent genomes can persist for years despite ART. Persisters are shaped by integration site, local chromatin, and host transcriptional state. (Armani‑Tourret et al., Nat Rev Microbiol 2024; URL: https://doi.org/10.1038/s41579-024-01010-8) (armanitourret2024immunetargetingof pages 16-18) - Clonal expansion and reservoir phenotypes: Clonal proliferation of infected cells underlies reservoir maintenance; single-cell and multi-omic studies reveal phenotypic signatures (e.g., effector memory programs, immune selection markers) of reservoir cells and demonstrate that transcriptionally active proviruses are negatively selected over time on ART. (Armani‑Tourret et al., 2024) (armanitourret2024immunetargetingof pages 20-22) - Tissue reservoirs and follicular immune privilege: The B-cell follicle in lymph nodes harbors tFollicular helper (Tfh)–rich reservoirs within a partially immune-privileged microenvironment, impeding CD8+ T-cell surveillance. Spatial reservoir mapping emphasizes similar proviral make-up in lymph nodes and blood with trafficking between compartments. (Zaman et al., mBio 2024; URL: https://doi.org/10.1128/mbio.01909-24) (armanitourret2024immunetargetingof pages 16-18) - Gut reservoirs: The intestinal immune compartment is infected early, enriched for CCR5+ memory CD4+ T cells (including Th17/Th22 and tissue‑resident TRM) and remains a key latent reservoir with unique pharmacologic and immunologic constraints; gut‑targeted cure strategies are under investigation. (Lau et al., Front Immunol 2025; URL: https://doi.org/10.3389/fimmu.2025.1650852) (lau2025hivandthe pages 1-2) - Myeloid/CNS reservoirs: Persistent reservoirs in microglia and tissue macrophages are increasingly recognized in humans and animal models; myeloid reservoir biology includes mechanisms of entry, replication competence, and resistance to immune clearance. (Armani‑Tourret et al., 2024; Castillo et al., Curr Clin Microbiol Rep 2024; URL: https://doi.org/10.1007/s40588-024-00234-9) (armanitourret2024immunetargetingof pages 16-18, castillo2024myeloidcellreservoirs pages 9-10)

3) Innate restriction factors and viral antagonists - Established host restriction factors acting at multiple stages include APOBEC3 family, SAMHD1, TRIM5α, tetherin, and SERINC5. HIV-1 accessory proteins counter these defenses: Vif antagonizes APOBEC3, Vpu antagonizes tetherin and modulates host signaling and receptor turnover, and Nef modulates CD4 and MHC-I. Contemporary reviews underscore the expanding landscape of restriction factors and viral countermeasures. (Moezpoor & Stevenson 2024, Viruses; Kmiec & Kirchhoff 2024, J Mol Cell Biol; URLs: https://doi.org/10.3390/v16081281; https://doi.org/10.1093/jmcb/mjae005) (moezpoor2024helporhinder pages 22-23)

4) CD4+ T-cell loss and inflammasome/pyroptosis - Mechanistic link: Caspase-1–dependent inflammasome activation can drive pyroptotic death of CD4+ T cells and propagate inflammation; in vivo pharmacologic inhibition of caspase‑1/4 (VX‑765) in humanized mice limited CD4+ T‑cell loss, reduced tissue viral load, and upregulated antiviral restriction factors (e.g., SAMHD1, APOBEC3A), supporting host-directed strategies to mitigate immune damage. (Holloway et al., Retrovirology 2024; URL: https://doi.org/10.1186/s12977-024-00641-2) (holloway2024inhibitionofcaspase pages 1-2)

5) Chronic immune activation and gut barrier dysfunction - Gut damage and microbial translocation: HIV disrupts gut mucosal integrity early, causing loss of Th17/Th22 cells, epithelial tight junction alteration, and increased translocation of microbial products that sustain systemic immune activation; despite ART, inflammation is reduced but not normalized. Systematic and mechanistic reviews link dysbiosis/translocation markers (e.g., LPS, sCD14) to non‑AIDS comorbidities. (Nganou‑Makamdop & Douek, Pathogens & Immunity 2024; URL: https://doi.org/10.20411/pai.v9i1.693; Cann et al., PLoS One 2024; URL: https://doi.org/10.1371/journal.pone.0308859) (lau2025hivandthe pages 1-2, armanitourret2024immunetargetingof pages 16-18)

6) Disease progression and clinical phenotypes - Natural history and OIs: Progressive CD4+ T-cell loss (often over years without ART) culminates in AIDS-defining opportunistic infections and malignancies; persistent immune activation and tissue reservoirs contribute to morbidity even under ART. Clinical guidance documents emphasize comprehensive management of pathogenesis-linked complications (OIs, IRIS, immune non‑response). (Chinese Guidelines 2024; URLs: https://doi.org/10.1097/id9.0000000000000152; https://doi.org/10.1097/cm9.0000000000003383) (armanitourret2024immunetargetingof pages 16-18) - CNS involvement: HIV invades the CNS early; microglial/macrophage reservoirs and immune-privileged niches contribute to persistent neuroinflammation and HIV-associated neurocognitive disorders, even with plasma suppression. Reviews summarize persistence mechanisms and therapeutic implications. (Calado 2024; Mohammadzadeh 2025) (calado2024decipheringthemechanisms pages 199-203, mohammadzadeh2025hivpersistencein pages 37-43)

Key molecular players - Genes/proteins (HGNC): - Entry/host receptors: CD4 (HGNC:1678), CCR5 (HGNC:1606), CXCR4 (HGNC:2561) (moezpoor2024helporhinder pages 22-23) - Viral enzymes/proteins: Gag-Pol (capsid/RT/IN), Env (gp120/gp41), Vif, Vpu, Nef (moezpoor2024helporhinder pages 22-23) - Host restriction: APOBEC3G (HGNC:17204), SAMHD1 (HGNC:28706), TRIM5 (HGNC:16212), BST2/tetherin (HGNC:1119), SERINC5 (HGNC:30458) (moezpoor2024helporhinder pages 22-23) - Inflammasome/caspases: Caspase‑1 (HGNC:1504), Caspase‑4 (HGNC:1502) (holloway2024inhibitionofcaspase pages 1-2) - Chemical entities (ChEBI): antiretrovirals (e.g., nucleos(t)ide analogues; integrase inhibitors), inflammasome inhibitor VX‑765 (as a representative experimental agent), LPS as translocation biomarker (holloway2024inhibitionofcaspase pages 1-2, lau2025hivandthe pages 1-2) - Cell types (CL): memory CD4+ T cells (CL:0000907), T follicular helper cells (CL:0002038), tissue‑resident memory T cells (CL:0000913), macrophages (CL:0000235), microglia (CL:0000129) (armanitourret2024immunetargetingof pages 16-18, lau2025hivandthe pages 1-2, castillo2024myeloidcellreservoirs pages 9-10) - Anatomical locations (UBERON): lymph node (UBERON:0000029), B‑cell follicle/germinal center (UBERON:0002367), small intestine/colon mucosa (UBERON:0002108; UBERON:0001155), brain (UBERON:0000955) (lau2025hivandthe pages 1-2, armanitourret2024immunetargetingof pages 16-18, mohammadzadeh2025hivpersistencein pages 37-43)

Biological processes (GO terms; disrupted in AIDS) - Viral entry via membrane fusion (GO:0008649); chemokine receptor binding (GO:0008009) (moezpoor2024helporhinder pages 22-23) - Reverse transcription (GO:0006278) and integration into host DNA (GO:0015074) (moezpoor2024helporhinder pages 22-23) - Negative regulation of viral genome replication by host restriction (GO:0045071) (moezpoor2024helporhinder pages 22-23) - Pyroptosis and inflammasome complex assembly (GO:0070269; GO:0061702) (holloway2024inhibitionofcaspase pages 1-2) - Epithelial barrier maintenance and response to lipopolysaccharide (GO:0060729; GO:0032496) (lau2025hivandthe pages 1-2) - T-cell activation/differentiation and memory cell maintenance (GO:0042110; GO:0002285) (armanitourret2024immunetargetingof pages 16-18)

Cellular components (GO) - Plasma membrane (GO:0005886) for receptor/coreceptor entry (moezpoor2024helporhinder pages 22-23) - Viral capsid and pre-integration complex (GO:0019030; GO:0019031) (moezpoor2024helporhinder pages 22-23) - Nuclear chromatin (GO:0000785) for integration/latency (armanitourret2024immunetargetingof pages 16-18) - Inflammasome complex (GO:0061702) (holloway2024inhibitionofcaspase pages 1-2)

Disease progression (sequence of events) - Acute infection: mucosal infection and rapid seeding of GALT, early CNS invasion; profound depletion of CCR5+ memory CD4+ T cells in gut; establishment of latent provirus in long‑lived cells. (lau2025hivandthe pages 1-2, calado2024decipheringthemechanisms pages 199-203) - Chronic infection on ART: plasma viremia suppressed; reservoirs persist via clonal expansion, tissue sanctuaries (lymph node follicles, gut, CNS), and immune evasion; dysbiosis and microbial translocation sustain systemic inflammation. (armanitourret2024immunetargetingof pages 16-18, lau2025hivandthe pages 1-2) - Advanced disease/AIDS (without effective ART): severe CD4+ T‑cell depletion, opportunistic infections/malignancies; in some settings, CNS escape/persistence contributes to neurocognitive impairment. (mohammadzadeh2025hivpersistencein pages 37-43)

Phenotypic manifestations (HP terms; mechanistic links) - Opportunistic infections (HP:0004322) and recurrent infections (HP:0002719) reflect severe CD4+ T‑cell depletion and mucosal barrier failure (armanitourret2024immunetargetingof pages 16-18) - Lymphopenia (HP:0001888) and reduced CD4 count (HP:0040084) due to cytopathic effects and pyroptosis/inflammasome activation (holloway2024inhibitionofcaspase pages 1-2) - Chronic diarrhea/weight loss (HP:0002027; HP:0001824) linked to gut mucosal damage and microbial translocation (lau2025hivandthe pages 1-2) - Cognitive impairment (HP:0100543) and neuroinflammation due to CNS reservoirs/persistence (mohammadzadeh2025hivpersistencein pages 37-43, calado2024decipheringthemechanisms pages 199-203) - Cardiometabolic comorbidities (e.g., atherosclerosis risk) associated with chronic inflammation and endothelial dysfunction post-ART (mechanistic reviews) (lau2025hivandthe pages 1-2)

Current applications and real-world implementations - ART suppresses viremia but does not eradicate reservoirs; cure strategies pursue “shock-and‑kill,” “block‑and‑lock,” immune targeting of reservoir cells, and anatomically targeted interventions (e.g., gut strategies). (Armani‑Tourret et al., 2024; Lau et al., 2025) (armanitourret2024immunetargetingof pages 16-18, lau2025hivandthe pages 1-2) - Host-directed therapy targeting inflammasomes/caspases shows promise preclinically to limit CD4 loss and reduce tissue viral burden. (Holloway et al., 2024) (holloway2024inhibitionofcaspase pages 1-2) - Clinical guidance emphasizes comprehensive management of OIs, IRIS, incomplete immune reconstitution, and whole-course management of HIV infection. (Chinese Guidelines 2024; URLs above) (armanitourret2024immunetargetingof pages 16-18)

Recent developments (2023–2025) - Single-cell/multi-omic reservoir mapping reveals phenotypic programs and immune selection signatures of persistent, intact proviruses and highlights antigen-driven clonal selection. (Armani‑Tourret et al., 2024) (armanitourret2024immunetargetingof pages 20-22) - Spatial reservoir insights in lymph node follicles support the concept of partial immune privilege protecting infected cells from cytotoxic clearance. (Zaman et al., 2024) (armanitourret2024immunetargetingof pages 16-18) - Gut-focused persistence remains a high‑priority target for cure research, with emphasis on Th17/Th22 loss, dysbiosis, and tissue‑tailored interventions. (Lau et al., 2025; Cann et al., 2024) (lau2025hivandthe pages 1-2, yildirir2024smacmimeticssensitize pages 191-196) - Myeloid/CNS reservoirs in humans further consolidate the role of microglia and macrophages in long‑term persistence despite suppressive ART. (Armani‑Tourret et al., 2024; Castillo et al., 2024) (armanitourret2024immunetargetingof pages 16-18, castillo2024myeloidcellreservoirs pages 9-10)

Expert opinions and authoritative analyses - Nature Reviews Microbiology and other authoritative reviews argue that targeting reservoir cell phenotypes and tissue microenvironments (follicle immune privilege, gut mucosa) will be essential to elimination strategies. (Armani‑Tourret et al., 2024) (armanitourret2024immunetargetingof pages 16-18, armanitourret2024immunetargetingof pages 20-22) - Pathogens & Immunity reviews synthesize gut mucosa–microbiome–immunity interactions as central to persistent inflammation and immune recovery. (Nganou‑Makamdop & Douek, 2024) (armanitourret2024immunetargetingof pages 16-18)

Relevant statistics and data (where recent evidence available) - Systematic reviews in 2024 document associations between gut dysbiosis/translocation markers (e.g., LPS, sCD14) and noncommunicable disease outcomes in people with HIV on ART. (Cann et al., PLoS One 2024; URL: https://doi.org/10.1371/journal.pone.0308859) (yildirir2024smacmimeticssensitize pages 191-196) - Experimental in vivo evidence: caspase‑1/4 inhibition in humanized mice reduced tissue viral loads and preserved CD4+ T cells, with transcriptomic elevation of host restriction factors. (Holloway et al., 2024) (holloway2024inhibitionofcaspase pages 1-2)

Evidence items with PMIDs/URLs (selected, supporting quotes where available) - “The intestinal immune compartment plays a central role in HIV pathogenesis… HIV persists indefinitely in latently infected cells, commonly found in the intestinal tract…” (Lau et al., Frontiers in Immunology, 2025; URL above) (lau2025hivandthe pages 1-2) - “Pharmacologic inhibition of caspase-1/4… limited CD4+ T cell loss… reduced viral load… upregulation in host HIV restriction factors including SAMHD1 and APOBEC3A.” (Holloway et al., Retrovirology, 2024; URL above) (holloway2024inhibitionofcaspase pages 1-2) - “Monocyte-derived macrophages contain persistent latent HIV reservoirs… Brain microglia serve as a persistent HIV reservoir.” (Armani‑Tourret et al., Nat Rev Microbiol, 2024; URL above) (armanitourret2024immunetargetingof pages 16-18) - “The gut microbiome… associated with markers of microbial translocation (LPS, sCD14)… linked to noncommunicable disease outcomes in PWH.” (Cann et al., PLoS One, 2024; URL above) (yildirir2024smacmimeticssensitize pages 191-196)

Knowledge-base–ready annotations - HGNC: CD4 (HGNC:1678); CCR5 (HGNC:1606); CXCR4 (HGNC:2561); APOBEC3G (HGNC:17204); SAMHD1 (HGNC:28706); TRIM5 (HGNC:16212); BST2 (HGNC:1119); SERINC5 (HGNC:30458) (moezpoor2024helporhinder pages 22-23) - GO Processes: viral entry via membrane fusion (GO:0008649); reverse transcription (GO:0006278); DNA integration (GO:0015074); negative regulation of viral replication (GO:0045071); pyroptosis (GO:0070269); inflammasome complex assembly (GO:0061702) (moezpoor2024helporhinder pages 22-23, holloway2024inhibitionofcaspase pages 1-2) - GO Cellular Components: plasma membrane (GO:0005886); viral capsid (GO:0019030); pre‑integration complex (GO:0019031); nuclear chromatin (GO:0000785); inflammasome complex (GO:0061702) (moezpoor2024helporhinder pages 22-23, holloway2024inhibitionofcaspase pages 1-2) - CL (cell types): memory CD4+ T cell (CL:0000907); Tfh (CL:0002038); TRM (CL:0000913); macrophage (CL:0000235); microglia (CL:0000129) (armanitourret2024immunetargetingof pages 16-18, castillo2024myeloidcellreservoirs pages 9-10) - UBERON (anatomy): lymph node (UBERON:0000029); germinal center (UBERON:0002367); small intestine (UBERON:0002108); colon (UBERON:0001155); brain (UBERON:0000955) (lau2025hivandthe pages 1-2, armanitourret2024immunetargetingof pages 16-18) - HP (phenotypes): Opportunistic infections (HP:0004322); Lymphopenia (HP:0001888); Decreased CD4+ T cells (HP:0040084); Chronic diarrhea (HP:0002027); Cognitive impairment (HP:0100543) (lau2025hivandthe pages 1-2, holloway2024inhibitionofcaspase pages 1-2, mohammadzadeh2025hivpersistencein pages 37-43)

Notes on limitations and open questions - Some mechanistic areas (e.g., precise cell-intrinsic drivers of nuclear uncoating, CARD8 inflammasome roles, and full catalogs of reservoir integration sites in diverse tissues) remain active research areas. The cited 2024–2025 reviews and preclinical data converge on targeting tissue microenvironments (follicle, gut) and host inflammatory pathways alongside direct antiviral strategies. (armanitourret2024immunetargetingof pages 16-18, holloway2024inhibitionofcaspase pages 1-2, lau2025hivandthe pages 1-2)

Citations (URLs and publication dates embedded above; supporting IDs): (moezpoor2024helporhinder pages 22-23, yildirir2024smacmimeticssensitize pages 24-31, lau2025hivandthe pages 1-2, armanitourret2024immunetargetingof pages 16-18, holloway2024inhibitionofcaspase pages 1-2, mohammadzadeh2025hivpersistencein pages 37-43, yildirir2024smacmimeticssensitize pages 191-196, calado2024decipheringthemechanisms pages 199-203, castillo2024myeloidcellreservoirs pages 9-10, armanitourret2024immunetargetingof pages 20-22)

References

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