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3
Pathophys.
1
Histopath.
8
Phenotypes
2
Hypotheses
2
Gaps
2
Pathograph
2
Genes
4
Medical Actions
5
Differentials
2
References
1
Deep Research
🏷

Classifications

Harrison's Chapter
IMMUNE_RHEUMATOLOGIC INFECTIOUS_DISEASES

Mechanistic Hypotheses

2
Exuberant CD8 T-cell and interferon-driven immune response
immune_dysregulation CANONICAL
KFD is modeled as an exaggerated but self-limited cell-mediated immune response in which CD8-positive cytotoxic T cells and histiocytes drive apoptotic (karyorrhectic) necrosis, with a plasmacytoid dendritic cell and type I interferon component, sitting on a mechanistic spectrum toward systemic lupus erythematosus. This is the best-supported framework, but the precise trigger and initiating antigen remain unproven.
Show evidence (1 reference)
PMID:9839173 SUPPORT In Vitro
"In histiocytic necrotizing lymphadenitis (HNL), apoptosis is the main form of cell death."
Immunohistochemical and flow-cytometric analysis of HNL nodal tissue establishes apoptosis as the principal form of cell death, the basis of the immune-dysregulation model.
Hypothesized viral or infectious trigger
infectious_trigger EMERGING
A viral or other infectious agent is hypothesized to trigger KFD in a genetically susceptible host, based on temporal, serological, and case associations with agents such as EBV and human herpesviruses and on an interferon signature. No organism has been consistently isolated or shown to be causal, so the infectious etiology remains a hypothesis rather than an established fact.
Show evidence (2 references)
PMID:24594231 PARTIAL Human Clinical
"Epstein-Barr virus (EBV) has been implicated as a cause of HNL in some reports but not in others."
Directly documents that a viral (EBV) etiology has been proposed but is inconsistent across studies, supporting an unproven infectious-trigger hypothesis rather than established causation.
PMID:36451640 PARTIAL Human Clinical
"Although the clinical and histopathological features point to a viral etiology, this hypothesis has not been proven yet."
Explicitly frames the viral etiology as an unproven hypothesis, supporting the emerging (not canonical) status of the infectious trigger.
?

Discussions and Knowledge Gaps

2
How should the strong but longitudinal association between Kikuchi-Fujimoto disease and systemic lupus erythematosus be modeled and surveilled?
INTERPRETATION OPEN kfd_sle_association
KFD has a well-recognized, complex association with systemic lupus erythematosus (SLE): SLE may precede, develop after, or occur concurrently with KFD. Recurrent KFD, higher ANA positivity, and low C4 mark an intermediate status toward overt autoimmune disease, so KFD patients warrant long-term follow-up with ANA and complement monitoring for evolving SLE. This is modeled as a discussion rather than a structured comorbidity because KFD-SLE is a longitudinal association/overlap rather than a fixed co-occurrence.
Show evidence (2 references)
PMID:37383134 SUPPORT Human Clinical
"Both Kikuchi-Fujimoto disease and systemic lupus erythematosus share an obscure and complex relationship as systemic lupus erythematosus may occasionally precede, develop subsequently, or sometimes be associated concurrently with Kikuchi-Fujimoto disease."
Documents the temporal complexity of the KFD-SLE association, motivating SLE surveillance.
PMID:39961627 SUPPORT Human Clinical
"patients with recurrent KFD represent an intermediate status between those with transient KFD and those with overt autoimmune disease"
Supports recurrent KFD as an intermediate state toward autoimmune disease, reinforcing the need for autoimmune surveillance.
Is there a validated animal or in vivo model that recapitulates Kikuchi-Fujimoto disease?
KNOWLEDGE GAP OPEN kfd_no_animal_model
Attached to
CD8 T-Cell- and Histiocyte-Mediated Apoptotic Necrosis
There is no established animal (mouse, rat, zebrafish, or other in vivo) model that recapitulates KFD. Mechanistic understanding rests almost entirely on immunohistochemistry and in-situ studies of human lymph-node tissue, so causal mechanisms remain hypotheses. All KFD mechanistic evidence in this entry is therefore tagged HUMAN_CLINICAL or IN_VITRO (tissue-based); none is MODEL_ORGANISM because no faithful animal model data exist.

Pathophysiology

3
CD8 T-Cell- and Histiocyte-Mediated Apoptotic Necrosis
In KFD lesions, an exaggerated cell-mediated immune response produces apoptotic cell death driven predominantly by CD8-positive cytotoxic T cells, acting through the Fas-Fas ligand and perforin/granzyme pathways. Histiocytes (macrophages) act as enhancers and phagocytose the apoptotic debris, generating paracortical foci of necrosis rich in karyorrhectic (nuclear) debris characteristically without neutrophils.
CD8-positive cytotoxic T cell CL:0000625 Histiocyte (macrophage) CL:0000235
Apoptotic process GO:0006915 ↑ INCREASED T cell mediated cytotoxicity GO:0001913 ↑ INCREASED Extrinsic (Fas) apoptotic signaling GO:0097191 ↑ INCREASED
Show evidence (2 references)
PMID:9839173 SUPPORT In Vitro
"Two molecular mechanisms of T-cell-mediated cytotoxicity, one perforin-based and the other Fas-based, have been demonstrated, and both systems induce apoptosis of the target cells."
Immunohistochemistry of HNL nodal tissue shows Fas/FasL- and perforin/granzyme-positive cells confined to necrotizing lesions, with CD8-positive lymphocytes as effector and target cells and histiocytes as enhancers, supporting CD8 T-cell-driven apoptotic necrosis.
PMID:9839173 SUPPORT In Vitro
"the apoptotic cells were T-cells, especially CD8-positive cells rather than CD4-positive cells"
Identifies CD8-positive T cells as the predominant apoptotic population, supporting the CD8-cytotoxic-T-cell-centered mechanism.
Plasmacytoid Dendritic Cell Infiltration and Type I Interferon Signature
Lesional areas contain a characteristic infiltrate of immature dendritic cells, including plasmacytoid dendritic cells (CD123/CD303-positive), that strongly express the interferon-alpha-inducible protein MxA, indicating a type I interferon (interferon-alpha) response that parallels the interferon signature seen in systemic lupus erythematosus.
Plasmacytoid dendritic cell CL:0000784
Type I interferon-mediated signaling pathway GO:0060337 ↑ INCREASED Inflammatory response GO:0006954 ↑ INCREASED
Show evidence (2 references)
PMID:19141377 SUPPORT In Vitro
"the morphologically distinctive mononuclear cells in lesional areas consisted of 2 populations of immature DCs: myeloid DCs immunoreactive for CD1c with coexpression of myeloid antigens CD13 and CD33 and plasmacytoid DCs immunoreactive for CD303 and CD123"
Cryostat-section immunophenotyping of KFD lesions identifies plasmacytoid and myeloid immature dendritic cells as the distinctive lesional mononuclear cells.
PMID:19141377 SUPPORT In Vitro
"These cells were CD68+, strongly expressed the IFN-alpha inducible protein MxA, and were nonreactive for fascin, a mature DC marker."
Strong MxA expression by the lesional dendritic cells demonstrates a type I interferon (interferon-alpha) signature in KFD.
Paracortical Necrosis with Karyorrhexis and Self-Limited Lymphadenitis
The converging cytotoxic and histiocytic response produces the clinical hallmark: subacute, often tender regional (typically cervical) lymphadenopathy with fever, arising from paracortical necrosis rich in apoptotic karyorrhectic debris. The process is self-limited and usually resolves spontaneously over weeks to months.
Show evidence (2 references)
PMID:39961627 SUPPORT Human Clinical
"Kikuchi-Fujimoto disease (KFD) is a rare disease that typically manifests with fever and cervical lymphadenopathy."
Confirms the characteristic clinical outcome of the pathophysiologic cascade: fever with cervical lymphadenopathy.
PMID:28613580 SUPPORT Human Clinical
"Kikuchi-Fujimoto disease typically follows a self-limiting course lasting several months"
Documents the self-limited, spontaneously resolving natural history of the lymphadenitis.

Histopathology

1
Paracortical Necrosis with Karyorrhexis
The diagnostic core of KFD is paracortical (T-zone) foci of necrosis with abundant apoptotic karyorrhectic (nuclear) debris, an infiltrate of crescentic histiocytes (CD68-positive, myeloperoxidase-positive), plasmacytoid dendritic cells, and CD8-positive T cells, with a characteristic absence of neutrophils and a paucity of plasma cells and B cells. Fine-needle aspiration is often inadequate; excisional lymph-node biopsy is required.
Show evidence (2 references)
PMID:28613580 SUPPORT Human Clinical
"An excisional lymph node biopsy is imperative for confirming a definitive diagnosis, revealing a deficiency of neutrophils and eosinophils."
Documents the diagnostic requirement for excisional biopsy and the characteristic deficiency of neutrophils, a key distinguishing histologic feature of KFD.
PMID:28613580 SUPPORT Human Clinical
"Immunohistochemistry will demonstrate histiocytes positive for myeloperoxidase and CD68, T cells positive for CD8, and a minimal presence of B cells."
Establishes the characteristic immunophenotype: CD68/MPO-positive histiocytes, CD8-positive T cells, and scant B cells.

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Kikuchi-Fujimoto Disease 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

8
Blood 1
Leukopenia Decreased total leukocyte count HP:0001882
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients"
Documents leukopenia (leucopenia) as a laboratory feature of KFD.
Cardiovascular 2
Cervical lymphadenopathy Cervical lymphadenopathy HP:0025289
Temporal: SUBACUTE
Show evidence (1 reference)
PMID:36451640 SUPPORT Human Clinical
"Kikuchi-Fujimoto disease (KFD) is a benign disorder characterized by regional cervical lymphadenopathy with tenderness."
Directly documents tender regional cervical lymphadenopathy as the characteristic presentation.
Splenomegaly Splenomegaly HP:0001744
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients"
Documents splenomegaly as a feature of severely affected KFD patients.
Immune 1
Skin rash FREQUENT Skin rash HP:0000988
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"Cutaneous involvement occurs in about 30%-40% of cases as facial erythema and nonspecific erythematous papules, plaques, acneiform or morbilliform lesions"
Reports cutaneous involvement in about 30-40% of cases, supporting a FREQUENT (30-79%) frequency band for skin rash.
Metabolism 1
Fever Fever HP:0001945
Show evidence (1 reference)
PMID:39961627 SUPPORT Human Clinical
"Kikuchi-Fujimoto disease (KFD) is a rare disease that typically manifests with fever and cervical lymphadenopathy."
Documents fever as a typical manifestation of KFD.
Constitutional 1
Night sweats Night sweats HP:0030166
Show evidence (1 reference)
PMID:36451640 SUPPORT Human Clinical
"Associated symptoms of KFD include low-grade fever, night sweats, weight loss, nausea, and sore throat."
Lists night sweats among the associated constitutional symptoms of KFD.
Growth 1
Weight loss Weight loss HP:0001824
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients"
Documents weight loss as a feature of severely affected KFD patients.
Other 1
Elevated erythrocyte sedimentation rate Elevated erythrocyte sedimentation rate HP:0003565
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients"
Documents an elevated erythrocyte sedimentation rate in KFD.
🧬

Genetic Associations

2
HLA-DPB1
Gene: HLA-DPB1 hgnc:4940 relationship_type: RISK_FACTOR variant_origin: GERMLINE
Show evidence (1 reference)
PMID:10519361 SUPPORT Human Clinical
"we found DPA1*01 and DPB1*0202 allele frequencies in HLA class II genes are significantly higher in HNL patients than in normal controls"
A case-control DNA-typing study of 86 HNL patients versus 525 controls found HLA-DPB1*0202 and HLA-DPA1*01 significantly over-represented, establishing an HLA class II susceptibility association.
HLA-DPA1
Gene: HLA-DPA1 hgnc:4938 relationship_type: RISK_FACTOR variant_origin: GERMLINE
Show evidence (1 reference)
PMID:10519361 SUPPORT Human Clinical
"HLA class II genes of HNL and the incidence of HNL in Asian countries, including Japan, might have a positive relationship to DPA1*01 and DPB1*0202 allele"
Links the HLA-DPA1*01 (and DPB1*0202) alleles to HNL and to its higher incidence in Asian populations, supporting HLA-DPA1 as a susceptibility locus.
💊

Medical Actions

4
Supportive care
Action: Supportive Care NCIT:C15747
Because KFD is self-limiting, most patients require only supportive care (hydration, antipyretics, monitoring) and reassurance while the disease resolves spontaneously.
Show evidence (1 reference)
PMID:28613580 SUPPORT Human Clinical
"The management of Kikuchi-Fujimoto disease primarily involves supportive care for patients, with the use of corticosteroids and immunosuppression reserved for cases of severe or recurrent disease."
Establishes supportive care as the primary management, with corticosteroids/immunosuppression reserved for severe or recurrent disease.
NSAIDs and analgesics
Action: Pharmacotherapy NCIT:C15986
Agent: ibuprofen (representative NSAID) CHEBI:5855
Non-steroidal anti-inflammatory drugs (such as ibuprofen), antipyretics, and analgesics are used for symptom control (fever and painful nodes) in mild disease.
Show evidence (1 reference)
PMID:36451640 SUPPORT Human Clinical
"Supportive treatment includes antipyretics, non-steroidal anti-inflammatory drugs, and corticosteroids."
Documents NSAIDs and antipyretics as supportive treatment for KFD.
Systemic corticosteroids
Action: Pharmacotherapy NCIT:C15986
Agent: prednisolone (representative corticosteroid) CHEBI:8378
Systemic corticosteroids (e.g., prednisolone) hasten resolution and are reserved for severe, extranodal, or recurrent disease.
Show evidence (1 reference)
PMID:28613580 SUPPORT Human Clinical
"the use of corticosteroids and immunosuppression reserved for cases of severe or recurrent disease"
Documents systemic corticosteroids reserved for severe or recurrent KFD.
Hydroxychloroquine
Action: Pharmacotherapy NCIT:C15986
Agent: hydroxychloroquine CHEBI:5801
Hydroxychloroquine is used as an immunomodulatory agent in recurrent or corticosteroid-dependent disease and in cases with autoimmune (lupus) overlap.
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"Its treatment with systemic corticosteroids, hydroxychloroquine, or antimicrobial agents mostly remains empirical."
Documents hydroxychloroquine (with corticosteroids) as an empirical treatment for KFD.
🔬

Biochemical Markers

2
Leukopenia
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients"
Documents leukopenia as a laboratory abnormality in KFD.
Antinuclear antibody status
Show evidence (1 reference)
PMID:39961627 SUPPORT Human Clinical
"Recurrence was associated with lower C4 levels (P = 0.038) and higher antinuclear antibody (ANA) rates (P = 0.007) compared to transient disease."
Establishes ANA positivity and low C4 as markers associated with KFD recurrence and evolving autoimmunity.
🔀

Differential Diagnoses

5

Conditions with similar clinical presentations that must be differentiated from Kikuchi-Fujimoto Disease:

Systemic lupus erythematosus (lupus lymphadenitis) Not Yet Curated MONDO:0007915
Overlapping Features Lupus lymphadenitis can be histologically similar to KFD, but the presence of hematoxylin bodies (and abundant plasma cells) favors SLE. SLE is the autoimmune disease most strongly associated with KFD, and KFD patients require follow-up because they may develop SLE.
Distinguishing Features
  • KFD: paucity of plasma cells, no hematoxylin bodies, absence of neutrophils
  • SLE lymphadenitis: hematoxylin bodies present, abundant plasma cells
Show evidence (1 reference)
PMID:28613580 SUPPORT Human Clinical
"the presence of hematoxylin bodies in SLE lymphadenitis aids in its distinction from Kikuchi-Fujimoto disease"
Identifies hematoxylin bodies as the key histologic feature distinguishing SLE lymphadenitis from KFD.
Non-Hodgkin lymphoma Not Yet Curated MONDO:0018908
Overlapping Features Nodal lymphoma is the most important mimic of KFD because misdiagnosis can lead to unnecessary chemotherapy. KFD lacks a clonal lymphoid population; absence of clonal rearrangement and the characteristic histiocytic necrotizing pattern distinguish KFD from lymphoma.
Distinguishing Features
  • KFD: reactive polyclonal infiltrate, CD8 T cells, histiocytic karyorrhectic necrosis, no clonality
  • Non-Hodgkin lymphoma: clonal lymphoid population, effacement of architecture
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"It is often mistaken for non-Hodgkin lymphoma"
Documents non-Hodgkin lymphoma as the principal misdiagnosis of KFD, making it the key differential.
Tuberculous lymphadenitis Not Yet Curated MONDO:0005831
Overlapping Features Tuberculous (and other granulomatous infectious) lymphadenitis enters the differential for necrotizing lymphadenopathy; KFD characteristically lacks well-formed granulomas and neutrophils and shows apoptotic karyorrhexis instead of caseating necrosis with acid-fast bacilli.
Distinguishing Features
  • KFD: apoptotic karyorrhexis, no granulomas, no neutrophils, culture/AFB negative
  • Tuberculous lymphadenitis: caseating granulomas, acid-fast bacilli
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's disease, drug eruptions, infectious mononucleosis, and viral or tubercular lymphadenitis are other common differentials"
Lists tubercular (and other infectious) lymphadenitis among the common differentials of KFD.
Overlapping Features Cat-scratch disease (Bartonella henselae) causes granulomatous, often suppurative regional lymphadenitis with neutrophilic microabscesses, in contrast to the neutrophil-poor apoptotic necrosis of KFD.
Distinguishing Features
  • KFD: apoptotic karyorrhexis, absence of neutrophils
  • Cat-scratch disease: stellate necrotizing granulomas with neutrophilic microabscesses, Bartonella exposure
Show evidence (1 reference)
PMID:37383134 SUPPORT Human Clinical
"lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's disease, drug eruptions, infectious mononucleosis, and viral or tubercular lymphadenitis are other common differentials"
Lists cat-scratch disease among the common differentials of KFD.
Overlapping Features Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is the other histiocytic lymphadenopathy in the differential. It is distinguished by S100-positive histiocytes exhibiting emperipolesis (the non-destructive engulfment of intact lymphocytes), which is absent in KFD; KFD instead shows CD8 T-cell-driven apoptotic karyorrhectic necrosis without emperipolesis.
Distinguishing Features
  • KFD: apoptotic karyorrhectic necrosis, CD8 T cells, no emperipolesis, S100 variable
  • Rosai-Dorfman disease: emperipolesis, S100-positive CD1a-negative histiocytes, massive painless lymphadenopathy
{ }

Source YAML

click to show
name: Kikuchi-Fujimoto Disease
creation_date: "2026-06-30T00:00:00Z"
category: Complex
disease_term:
  preferred_term: Kikuchi-Fujimoto disease
  term:
    id: MONDO:0018864
    label: Kikuchi-Fujimoto disease
parents:
- Lymphadenitis
description: >-
  Kikuchi-Fujimoto disease (KFD), also called histiocytic necrotizing
  lymphadenitis (HNL), is a rare, benign, and typically self-limiting systemic
  disorder of obscure etiology, first described independently in Japan in 1972
  by Kikuchi and Fujimoto. It most commonly affects young adults, historically
  with a female predominance and a higher reported incidence in Asian
  populations. The classic presentation is subacute, tender cervical
  lymphadenopathy with fever, often accompanied by night sweats, weight loss,
  leukopenia, and an elevated erythrocyte sedimentation rate, and sometimes
  skin rash, arthralgia, and hepatosplenomegaly. KFD is neither Mendelian nor
  neoplastic. Its diagnostic histopathologic hallmark is paracortical foci of
  necrosis with abundant karyorrhectic (nuclear) debris and a histiocytic
  infiltrate (crescentic histiocytes and plasmacytoid dendritic cells) together
  with CD8-positive cytotoxic T cells, with a characteristic absence of
  neutrophils and a paucity of plasma cells that helps distinguish it from
  lymphoma and lupus lymphadenitis. The mechanism is thought to be an
  exuberant, self-limited T-cell and histiocyte-mediated immune response in
  which apoptotic cell death is driven by CD8-positive cytotoxic T cells,
  possibly triggered by viral or other infectious agents in genetically
  predisposed individuals, though no causative agent has been proven. KFD has a
  strong recognized association with systemic lupus erythematosus and may
  precede, coincide with, or follow it, so lupus workup and long-term
  follow-up are important. The disorder usually resolves spontaneously within
  weeks to months; treatment is supportive (NSAIDs, analgesics), with
  corticosteroids and hydroxychloroquine reserved for severe or recurrent
  disease, and recurrence is uncommon.

references:
- reference: PMID:37383134
  title: "Kikuchi-Fujimoto disease: A comprehensive review."
- reference: PMID:39961627
  title: "Kikuchi-Fujimoto disease: investigating comprehensive clinicopathological features and risk factors for recurrence."

mechanistic_hypotheses:
- hypothesis_group_id: immune_dysregulation
  hypothesis_label: Exuberant CD8 T-cell and interferon-driven immune response
  status: CANONICAL
  description: >-
    KFD is modeled as an exaggerated but self-limited cell-mediated immune
    response in which CD8-positive cytotoxic T cells and histiocytes drive
    apoptotic (karyorrhectic) necrosis, with a plasmacytoid dendritic cell and
    type I interferon component, sitting on a mechanistic spectrum toward
    systemic lupus erythematosus. This is the best-supported framework, but the
    precise trigger and initiating antigen remain unproven.
  evidence:
  - reference: PMID:9839173
    reference_title: "Perforin and Fas pathways of cytotoxic T-cells in histiocytic necrotizing lymphadenitis."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      In histiocytic necrotizing lymphadenitis (HNL), apoptosis is the main
      form of cell death.
    explanation: >-
      Immunohistochemical and flow-cytometric analysis of HNL nodal tissue
      establishes apoptosis as the principal form of cell death, the basis of
      the immune-dysregulation model.
- hypothesis_group_id: infectious_trigger
  hypothesis_label: Hypothesized viral or infectious trigger
  status: EMERGING
  description: >-
    A viral or other infectious agent is hypothesized to trigger KFD in a
    genetically susceptible host, based on temporal, serological, and case
    associations with agents such as EBV and human herpesviruses and on an
    interferon signature. No organism has been consistently isolated or shown
    to be causal, so the infectious etiology remains a hypothesis rather than
    an established fact.
  evidence:
  - reference: PMID:24594231
    reference_title: "Comparison of clinical features and EBV expression in histiocytic necrotizing lymphadenitis of children and adults."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Epstein-Barr virus (EBV) has been implicated as a cause of HNL in some
      reports but not in others.
    explanation: >-
      Directly documents that a viral (EBV) etiology has been proposed but is
      inconsistent across studies, supporting an unproven infectious-trigger
      hypothesis rather than established causation.
  - reference: PMID:36451640
    reference_title: "Kikuchi-Fujimoto Disease: A Rare Cause of Pyrexia of Unknown Origin and Cervical Lymphadenopathy."
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Although the clinical and histopathological features point to a viral
      etiology, this hypothesis has not been proven yet.
    explanation: >-
      Explicitly frames the viral etiology as an unproven hypothesis,
      supporting the emerging (not canonical) status of the infectious trigger.

pathophysiology:
- name: CD8 T-Cell- and Histiocyte-Mediated Apoptotic Necrosis
  description: >-
    In KFD lesions, an exaggerated cell-mediated immune response produces
    apoptotic cell death driven predominantly by CD8-positive cytotoxic T
    cells, acting through the Fas-Fas ligand and perforin/granzyme pathways.
    Histiocytes (macrophages) act as enhancers and phagocytose the apoptotic
    debris, generating paracortical foci of necrosis rich in karyorrhectic
    (nuclear) debris characteristically without neutrophils.
  cell_types:
  - preferred_term: CD8-positive cytotoxic T cell
    term:
      id: CL:0000625
      label: CD8-positive, alpha-beta T cell
  - preferred_term: Histiocyte (macrophage)
    term:
      id: CL:0000235
      label: macrophage
  biological_processes:
  - preferred_term: Apoptotic process
    term:
      id: GO:0006915
      label: apoptotic process
    modifier: INCREASED
  - preferred_term: T cell mediated cytotoxicity
    term:
      id: GO:0001913
      label: T cell mediated cytotoxicity
    modifier: INCREASED
  - preferred_term: Extrinsic (Fas) apoptotic signaling
    term:
      id: GO:0097191
      label: extrinsic apoptotic signaling pathway
    modifier: INCREASED
  downstream:
  - target: Paracortical Necrosis with Karyorrhexis and Self-Limited Lymphadenitis
    description: >-
      CD8 T-cell- and histiocyte-driven apoptosis produces the paracortical
      karyorrhectic necrosis that manifests clinically as self-limited
      lymphadenitis.
  evidence:
  - reference: PMID:9839173
    reference_title: "Perforin and Fas pathways of cytotoxic T-cells in histiocytic necrotizing lymphadenitis."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      Two molecular mechanisms of T-cell-mediated cytotoxicity, one
      perforin-based and the other Fas-based, have been demonstrated, and both
      systems induce apoptosis of the target cells.
    explanation: >-
      Immunohistochemistry of HNL nodal tissue shows Fas/FasL- and
      perforin/granzyme-positive cells confined to necrotizing lesions, with
      CD8-positive lymphocytes as effector and target cells and histiocytes as
      enhancers, supporting CD8 T-cell-driven apoptotic necrosis.
  - reference: PMID:9839173
    reference_title: "Perforin and Fas pathways of cytotoxic T-cells in histiocytic necrotizing lymphadenitis."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      the apoptotic cells were T-cells, especially CD8-positive cells rather
      than CD4-positive cells
    explanation: >-
      Identifies CD8-positive T cells as the predominant apoptotic population,
      supporting the CD8-cytotoxic-T-cell-centered mechanism.
- name: Plasmacytoid Dendritic Cell Infiltration and Type I Interferon Signature
  description: >-
    Lesional areas contain a characteristic infiltrate of immature dendritic
    cells, including plasmacytoid dendritic cells (CD123/CD303-positive), that
    strongly express the interferon-alpha-inducible protein MxA, indicating a
    type I interferon (interferon-alpha) response that parallels the
    interferon signature seen in systemic lupus erythematosus.
  cell_types:
  - preferred_term: Plasmacytoid dendritic cell
    term:
      id: CL:0000784
      label: plasmacytoid dendritic cell
  biological_processes:
  - preferred_term: Type I interferon-mediated signaling pathway
    term:
      id: GO:0060337
      label: type I interferon-mediated signaling pathway
    modifier: INCREASED
  - preferred_term: Inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  evidence:
  - reference: PMID:19141377
    reference_title: "Histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease): lesional cells exhibit an immature dendritic cell phenotype."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      the morphologically distinctive mononuclear cells in lesional areas
      consisted of 2 populations of immature DCs: myeloid DCs immunoreactive
      for CD1c with coexpression of myeloid antigens CD13 and CD33 and
      plasmacytoid DCs immunoreactive for CD303 and CD123
    explanation: >-
      Cryostat-section immunophenotyping of KFD lesions identifies plasmacytoid
      and myeloid immature dendritic cells as the distinctive lesional
      mononuclear cells.
  - reference: PMID:19141377
    reference_title: "Histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease): lesional cells exhibit an immature dendritic cell phenotype."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      These cells were CD68+, strongly expressed the IFN-alpha inducible
      protein MxA, and were nonreactive for fascin, a mature DC marker.
    explanation: >-
      Strong MxA expression by the lesional dendritic cells demonstrates a type
      I interferon (interferon-alpha) signature in KFD.
- name: Paracortical Necrosis with Karyorrhexis and Self-Limited Lymphadenitis
  description: >-
    The converging cytotoxic and histiocytic response produces the clinical
    hallmark: subacute, often tender regional (typically cervical)
    lymphadenopathy with fever, arising from paracortical necrosis rich in
    apoptotic karyorrhectic debris. The process is self-limited and usually
    resolves spontaneously over weeks to months.
  evidence:
  - reference: PMID:39961627
    reference_title: "Kikuchi-Fujimoto disease: investigating comprehensive clinicopathological features and risk factors for recurrence."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Kikuchi-Fujimoto disease (KFD) is a rare disease that typically manifests
      with fever and cervical lymphadenopathy.
    explanation: >-
      Confirms the characteristic clinical outcome of the pathophysiologic
      cascade: fever with cervical lymphadenopathy.
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Kikuchi-Fujimoto disease typically follows a self-limiting course lasting
      several months
    explanation: >-
      Documents the self-limited, spontaneously resolving natural history of
      the lymphadenitis.

phenotypes:
- category: Clinical
  name: Cervical lymphadenopathy
  description: >-
    Subacute, often tender, regional cervical lymphadenopathy is the hallmark
    and most consistent presentation of KFD.
  phenotype_term:
    preferred_term: Cervical lymphadenopathy
    term:
      id: HP:0025289
      label: Cervical lymphadenopathy
    temporality: SUBACUTE
  evidence:
  - reference: PMID:36451640
    reference_title: "Kikuchi-Fujimoto Disease: A Rare Cause of Pyrexia of Unknown Origin and Cervical Lymphadenopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Kikuchi-Fujimoto disease (KFD) is a benign disorder characterized by
      regional cervical lymphadenopathy with tenderness.
    explanation: >-
      Directly documents tender regional cervical lymphadenopathy as the
      characteristic presentation.
- category: Clinical
  name: Fever
  description: Low-grade to moderate intermittent fever is a common presenting feature.
  phenotype_term:
    preferred_term: Fever
    term:
      id: HP:0001945
      label: Fever
  evidence:
  - reference: PMID:39961627
    reference_title: "Kikuchi-Fujimoto disease: investigating comprehensive clinicopathological features and risk factors for recurrence."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Kikuchi-Fujimoto disease (KFD) is a rare disease that typically manifests
      with fever and cervical lymphadenopathy.
    explanation: Documents fever as a typical manifestation of KFD.
- category: Clinical
  name: Night sweats
  description: Night sweats are a common associated constitutional symptom.
  phenotype_term:
    preferred_term: Night sweats
    term:
      id: HP:0030166
      label: Night sweats
  evidence:
  - reference: PMID:36451640
    reference_title: "Kikuchi-Fujimoto Disease: A Rare Cause of Pyrexia of Unknown Origin and Cervical Lymphadenopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Associated symptoms of KFD include low-grade fever, night sweats, weight
      loss, nausea, and sore throat.
    explanation: Lists night sweats among the associated constitutional symptoms of KFD.
- category: Clinical
  name: Weight loss
  description: Weight loss is an associated constitutional symptom, more common in severe disease.
  phenotype_term:
    preferred_term: Weight loss
    term:
      id: HP:0001824
      label: Weight loss
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      weight loss, splenomegaly, leucopenia, and elevated erythrocyte
      sedimentation rate feature in severely affected patients
    explanation: Documents weight loss as a feature of severely affected KFD patients.
- category: Laboratory
  name: Leukopenia
  description: >-
    Leukopenia (decreased total leukocyte count) is the commonest laboratory
    abnormality in KFD.
  phenotype_term:
    preferred_term: Leukopenia
    term:
      id: HP:0001882
      label: Decreased total leukocyte count
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      weight loss, splenomegaly, leucopenia, and elevated erythrocyte
      sedimentation rate feature in severely affected patients
    explanation: Documents leukopenia (leucopenia) as a laboratory feature of KFD.
- category: Laboratory
  name: Elevated erythrocyte sedimentation rate
  description: An elevated ESR is a common inflammatory laboratory finding in KFD.
  phenotype_term:
    preferred_term: Elevated erythrocyte sedimentation rate
    term:
      id: HP:0003565
      label: Elevated erythrocyte sedimentation rate
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      weight loss, splenomegaly, leucopenia, and elevated erythrocyte
      sedimentation rate feature in severely affected patients
    explanation: Documents an elevated erythrocyte sedimentation rate in KFD.
- category: Clinical
  name: Skin rash
  description: >-
    Cutaneous involvement occurs in a substantial minority as facial erythema
    and nonspecific erythematous papules, plaques, or acneiform/morbilliform
    lesions.
  phenotype_term:
    preferred_term: Skin rash
    term:
      id: HP:0000988
      label: Skin rash
  frequency: FREQUENT
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Cutaneous involvement occurs in about 30%-40% of cases as facial erythema
      and nonspecific erythematous papules, plaques, acneiform or morbilliform
      lesions
    explanation: >-
      Reports cutaneous involvement in about 30-40% of cases, supporting a
      FREQUENT (30-79%) frequency band for skin rash.
- category: Clinical
  name: Splenomegaly
  description: Splenomegaly occurs in severely affected patients.
  phenotype_term:
    preferred_term: Splenomegaly
    term:
      id: HP:0001744
      label: Splenomegaly
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      weight loss, splenomegaly, leucopenia, and elevated erythrocyte
      sedimentation rate feature in severely affected patients
    explanation: Documents splenomegaly as a feature of severely affected KFD patients.

genetic:
- name: HLA-DPB1
  notes: >-
    KFD is not a Mendelian disorder and has no causal gene. The principal
    genetic signal is an HLA class II susceptibility association: the
    HLA-DPB1*0202 allele (and HLA-DPA1*01) is significantly over-represented in
    Japanese KFD patients relative to controls. These are common germline
    population variants conferring susceptibility, not pathogenic mutations,
    and their higher frequency in East Asians may contribute to the observed
    Asian predominance.
  gene_term:
    preferred_term: HLA-DPB1
    term:
      id: hgnc:4940
      label: HLA-DPB1
  variant_origin: GERMLINE
  relationship_type: RISK_FACTOR
  evidence:
  - reference: PMID:10519361
    reference_title: "DNA typing of HLA class II genes (HLA-DR, -DQ and -DP) in Japanese patients with histiocytic necrotizing lymphadenitis (Kikuchi's disease)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we found DPA1*01 and DPB1*0202 allele frequencies in HLA class II genes
      are significantly higher in HNL patients than in normal controls
    explanation: >-
      A case-control DNA-typing study of 86 HNL patients versus 525 controls
      found HLA-DPB1*0202 and HLA-DPA1*01 significantly over-represented,
      establishing an HLA class II susceptibility association.
- name: HLA-DPA1
  notes: >-
    The HLA-DPA1*01 allele is over-represented alongside HLA-DPB1*0202 in
    Japanese KFD patients. As with HLA-DPB1, this is a germline susceptibility
    association, not a causal Mendelian mutation.
  gene_term:
    preferred_term: HLA-DPA1
    term:
      id: hgnc:4938
      label: HLA-DPA1
  variant_origin: GERMLINE
  relationship_type: RISK_FACTOR
  evidence:
  - reference: PMID:10519361
    reference_title: "DNA typing of HLA class II genes (HLA-DR, -DQ and -DP) in Japanese patients with histiocytic necrotizing lymphadenitis (Kikuchi's disease)."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      HLA class II genes of HNL and the incidence of HNL in Asian countries,
      including Japan, might have a positive relationship to DPA1*01 and
      DPB1*0202 allele
    explanation: >-
      Links the HLA-DPA1*01 (and DPB1*0202) alleles to HNL and to its higher
      incidence in Asian populations, supporting HLA-DPA1 as a susceptibility
      locus.

biochemical:
- name: Leukopenia
  notes: >-
    A reduced peripheral white blood cell count is the commonest laboratory
    abnormality; atypical lymphocytes may be present.
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      weight loss, splenomegaly, leucopenia, and elevated erythrocyte
      sedimentation rate feature in severely affected patients
    explanation: Documents leukopenia as a laboratory abnormality in KFD.
- name: Antinuclear antibody status
  notes: >-
    ANA is usually negative at baseline in isolated KFD; ANA positivity (and
    low C4) is associated with recurrence and with an intermediate status
    toward overt autoimmune disease such as SLE, so it is an important
    prognostic and surveillance marker.
  evidence:
  - reference: PMID:39961627
    reference_title: "Kikuchi-Fujimoto disease: investigating comprehensive clinicopathological features and risk factors for recurrence."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Recurrence was associated with lower C4 levels (P = 0.038) and higher
      antinuclear antibody (ANA) rates (P = 0.007) compared to transient
      disease.
    explanation: >-
      Establishes ANA positivity and low C4 as markers associated with KFD
      recurrence and evolving autoimmunity.

histopathology:
- name: Paracortical Necrosis with Karyorrhexis
  finding_term:
    preferred_term: Paracortical necrosis with karyorrhectic (nuclear) debris
    term:
      id: NCIT:C36184
      label: Necrosis
  diagnostic: true
  description: >-
    The diagnostic core of KFD is paracortical (T-zone) foci of necrosis with
    abundant apoptotic karyorrhectic (nuclear) debris, an infiltrate of
    crescentic histiocytes (CD68-positive, myeloperoxidase-positive),
    plasmacytoid dendritic cells, and CD8-positive T cells, with a
    characteristic absence of neutrophils and a paucity of plasma cells and
    B cells. Fine-needle aspiration is often inadequate; excisional lymph-node
    biopsy is required.
  evidence:
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      An excisional lymph node biopsy is imperative for confirming a definitive
      diagnosis, revealing a deficiency of neutrophils and eosinophils.
    explanation: >-
      Documents the diagnostic requirement for excisional biopsy and the
      characteristic deficiency of neutrophils, a key distinguishing histologic
      feature of KFD.
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Immunohistochemistry will demonstrate histiocytes positive for
      myeloperoxidase and CD68, T cells positive for CD8, and a minimal
      presence of B cells.
    explanation: >-
      Establishes the characteristic immunophenotype: CD68/MPO-positive
      histiocytes, CD8-positive T cells, and scant B cells.

diagnosis:
- name: Excisional lymph node biopsy
  description: >-
    Definitive diagnosis is made by excisional lymph-node biopsy showing the
    characteristic histopathology; fine-needle aspiration is often
    nondiagnostic. Biopsy is essential to exclude lymphoma and to distinguish
    KFD from lupus lymphadenitis.
  evidence:
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      An excisional lymph node biopsy is imperative for confirming a definitive
      diagnosis, revealing a deficiency of neutrophils and eosinophils.
    explanation: Documents excisional lymph-node biopsy as the definitive diagnostic test.
- name: Exclusion of lymphoma and SLE
  description: >-
    KFD must be distinguished from non-Hodgkin lymphoma and from systemic lupus
    erythematosus lymphadenitis; the presence of hematoxylin bodies favors SLE
    lymphadenitis over KFD.
  evidence:
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Distinguishing Kikuchi-Fujimoto disease from lymphomas and infectious
      etiologies is critical
    explanation: >-
      Establishes the diagnostic imperative of excluding lymphoma and
      infectious mimics.

differential_diagnoses:
- name: Systemic lupus erythematosus (lupus lymphadenitis)
  description: >-
    Lupus lymphadenitis can be histologically similar to KFD, but the presence
    of hematoxylin bodies (and abundant plasma cells) favors SLE. SLE is the
    autoimmune disease most strongly associated with KFD, and KFD patients
    require follow-up because they may develop SLE.
  distinguishing_features:
  - "KFD: paucity of plasma cells, no hematoxylin bodies, absence of neutrophils"
  - "SLE lymphadenitis: hematoxylin bodies present, abundant plasma cells"
  evidence:
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the presence of hematoxylin bodies in SLE lymphadenitis aids in its
      distinction from Kikuchi-Fujimoto disease
    explanation: >-
      Identifies hematoxylin bodies as the key histologic feature
      distinguishing SLE lymphadenitis from KFD.
  disease_term:
    preferred_term: systemic lupus erythematosus
    term:
      id: MONDO:0007915
      label: systemic lupus erythematosus
- name: Non-Hodgkin lymphoma
  description: >-
    Nodal lymphoma is the most important mimic of KFD because misdiagnosis can
    lead to unnecessary chemotherapy. KFD lacks a clonal lymphoid population;
    absence of clonal rearrangement and the characteristic histiocytic
    necrotizing pattern distinguish KFD from lymphoma.
  distinguishing_features:
  - "KFD: reactive polyclonal infiltrate, CD8 T cells, histiocytic karyorrhectic necrosis, no clonality"
  - "Non-Hodgkin lymphoma: clonal lymphoid population, effacement of architecture"
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      It is often mistaken for non-Hodgkin lymphoma
    explanation: >-
      Documents non-Hodgkin lymphoma as the principal misdiagnosis of KFD,
      making it the key differential.
  disease_term:
    preferred_term: non-Hodgkin lymphoma
    term:
      id: MONDO:0018908
      label: non-Hodgkin lymphoma
- name: Tuberculous lymphadenitis
  description: >-
    Tuberculous (and other granulomatous infectious) lymphadenitis enters the
    differential for necrotizing lymphadenopathy; KFD characteristically lacks
    well-formed granulomas and neutrophils and shows apoptotic karyorrhexis
    instead of caseating necrosis with acid-fast bacilli.
  distinguishing_features:
  - "KFD: apoptotic karyorrhexis, no granulomas, no neutrophils, culture/AFB negative"
  - "Tuberculous lymphadenitis: caseating granulomas, acid-fast bacilli"
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's
      disease, drug eruptions, infectious mononucleosis, and viral or
      tubercular lymphadenitis are other common differentials
    explanation: >-
      Lists tubercular (and other infectious) lymphadenitis among the common
      differentials of KFD.
  disease_term:
    preferred_term: lymph node tuberculosis
    term:
      id: MONDO:0005831
      label: lymph node tuberculosis
- name: Cat-scratch disease
  description: >-
    Cat-scratch disease (Bartonella henselae) causes granulomatous, often
    suppurative regional lymphadenitis with neutrophilic microabscesses, in
    contrast to the neutrophil-poor apoptotic necrosis of KFD.
  distinguishing_features:
  - "KFD: apoptotic karyorrhexis, absence of neutrophils"
  - "Cat-scratch disease: stellate necrotizing granulomas with neutrophilic microabscesses, Bartonella exposure"
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's
      disease, drug eruptions, infectious mononucleosis, and viral or
      tubercular lymphadenitis are other common differentials
    explanation: Lists cat-scratch disease among the common differentials of KFD.
  disease_term:
    preferred_term: cat-scratch disease
    term:
      id: MONDO:0005692
      label: cat-scratch disease
- name: Rosai-Dorfman disease
  description: >-
    Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is
    the other histiocytic lymphadenopathy in the differential. It is
    distinguished by S100-positive histiocytes exhibiting emperipolesis (the
    non-destructive engulfment of intact lymphocytes), which is absent in KFD;
    KFD instead shows CD8 T-cell-driven apoptotic karyorrhectic necrosis
    without emperipolesis.
  distinguishing_features:
  - "KFD: apoptotic karyorrhectic necrosis, CD8 T cells, no emperipolesis, S100 variable"
  - "Rosai-Dorfman disease: emperipolesis, S100-positive CD1a-negative histiocytes, massive painless lymphadenopathy"
  disease_term:
    preferred_term: Rosai-Dorfman disease
    term:
      id: MONDO:0006412
      label: sinus histiocytosis with massive lymphadenopathy

treatments:
- name: Supportive care
  description: >-
    Because KFD is self-limiting, most patients require only supportive care
    (hydration, antipyretics, monitoring) and reassurance while the disease
    resolves spontaneously.
  treatment_term:
    preferred_term: Supportive Care
    term:
      id: NCIT:C15747
      label: Supportive Care
  evidence:
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The management of Kikuchi-Fujimoto disease primarily involves supportive
      care for patients, with the use of corticosteroids and immunosuppression
      reserved for cases of severe or recurrent disease.
    explanation: >-
      Establishes supportive care as the primary management, with
      corticosteroids/immunosuppression reserved for severe or recurrent
      disease.
- name: NSAIDs and analgesics
  description: >-
    Non-steroidal anti-inflammatory drugs (such as ibuprofen), antipyretics,
    and analgesics are used for symptom control (fever and painful nodes) in
    mild disease.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: ibuprofen (representative NSAID)
      term:
        id: CHEBI:5855
        label: ibuprofen
  evidence:
  - reference: PMID:36451640
    reference_title: "Kikuchi-Fujimoto Disease: A Rare Cause of Pyrexia of Unknown Origin and Cervical Lymphadenopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Supportive treatment includes antipyretics, non-steroidal
      anti-inflammatory drugs, and corticosteroids.
    explanation: >-
      Documents NSAIDs and antipyretics as supportive treatment for KFD.
- name: Systemic corticosteroids
  description: >-
    Systemic corticosteroids (e.g., prednisolone) hasten resolution and are
    reserved for severe, extranodal, or recurrent disease.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: prednisolone (representative corticosteroid)
      term:
        id: CHEBI:8378
        label: prednisolone
  evidence:
  - reference: PMID:28613580
    reference_title: "Kikuchi-Fujimoto Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the use of corticosteroids and immunosuppression reserved for cases of
      severe or recurrent disease
    explanation: >-
      Documents systemic corticosteroids reserved for severe or recurrent KFD.
- name: Hydroxychloroquine
  description: >-
    Hydroxychloroquine is used as an immunomodulatory agent in recurrent or
    corticosteroid-dependent disease and in cases with autoimmune (lupus)
    overlap.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: hydroxychloroquine
      term:
        id: CHEBI:5801
        label: hydroxychloroquine
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Its treatment with systemic corticosteroids, hydroxychloroquine, or
      antimicrobial agents mostly remains empirical.
    explanation: >-
      Documents hydroxychloroquine (with corticosteroids) as an empirical
      treatment for KFD.

discussions:
- discussion_id: kfd_sle_association
  kind: INTERPRETATION
  status: OPEN
  prompt: >-
    How should the strong but longitudinal association between Kikuchi-Fujimoto
    disease and systemic lupus erythematosus be modeled and surveilled?
  rationale: >-
    KFD has a well-recognized, complex association with systemic lupus
    erythematosus (SLE): SLE may precede, develop after, or occur concurrently
    with KFD. Recurrent KFD, higher ANA positivity, and low C4 mark an
    intermediate status toward overt autoimmune disease, so KFD patients
    warrant long-term follow-up with ANA and complement monitoring for evolving
    SLE. This is modeled as a discussion rather than a structured comorbidity
    because KFD-SLE is a longitudinal association/overlap rather than a fixed
    co-occurrence.
  evidence:
  - reference: PMID:37383134
    reference_title: "Kikuchi-Fujimoto disease: A comprehensive review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Both Kikuchi-Fujimoto disease and systemic lupus erythematosus share an
      obscure and complex relationship as systemic lupus erythematosus may
      occasionally precede, develop subsequently, or sometimes be associated
      concurrently with Kikuchi-Fujimoto disease.
    explanation: >-
      Documents the temporal complexity of the KFD-SLE association, motivating
      SLE surveillance.
  - reference: PMID:39961627
    reference_title: "Kikuchi-Fujimoto disease: investigating comprehensive clinicopathological features and risk factors for recurrence."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      patients with recurrent KFD represent an intermediate status between
      those with transient KFD and those with overt autoimmune disease
    explanation: >-
      Supports recurrent KFD as an intermediate state toward autoimmune
      disease, reinforcing the need for autoimmune surveillance.
- discussion_id: kfd_no_animal_model
  kind: KNOWLEDGE_GAP
  status: OPEN
  prompt: >-
    Is there a validated animal or in vivo model that recapitulates
    Kikuchi-Fujimoto disease?
  rationale: >-
    There is no established animal (mouse, rat, zebrafish, or other in vivo)
    model that recapitulates KFD. Mechanistic understanding rests almost
    entirely on immunohistochemistry and in-situ studies of human lymph-node
    tissue, so causal mechanisms remain hypotheses. All KFD mechanistic
    evidence in this entry is therefore tagged HUMAN_CLINICAL or IN_VITRO
    (tissue-based); none is MODEL_ORGANISM because no faithful animal model
    data exist.
  attaches_to:
  - CD8 T-Cell- and Histiocyte-Mediated Apoptotic Necrosis

classifications:
  harrisons_chapter:
  - classification_value: IMMUNE_RHEUMATOLOGIC
    evidence:
    - reference: PMID:39961627
      reference_title: "Kikuchi-Fujimoto disease: investigating comprehensive clinicopathological features and risk factors for recurrence."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        patients with recurrent KFD represent an intermediate status between
        those with transient KFD and those with overt autoimmune disease
      explanation: >-
        The immune-mediated nature and autoimmune (SLE) overlap support an
        immune/rheumatologic placement.
  - classification_value: INFECTIOUS_DISEASES
    evidence:
    - reference: PMID:36451640
      reference_title: "Kikuchi-Fujimoto Disease: A Rare Cause of Pyrexia of Unknown Origin and Cervical Lymphadenopathy."
      supports: PARTIAL
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Although the clinical and histopathological features point to a viral
        etiology, this hypothesis has not been proven yet.
      explanation: >-
        A hypothesized (unproven) infectious/viral trigger supports a secondary
        infectious-disease placement, framed as hypothesis rather than
        established cause.

notes: >-
  Curation informed by a claude_code deep-research report
  (research/Kikuchi-Fujimoto_Disease-deep-research-claude_code.md) used as
  leads only. All evidence snippets were independently verified as exact
  substrings of cached PubMed abstracts. NEC preflight: MONDO:0018864 confirmed
  via OAK as Kikuchi-Fujimoto disease / histiocytic necrotizing lymphadenitis
  (is_a lymphadenitis), and the entry is anchored on that identity, not on
  Rosai-Dorfman disease, lymphoma, or SLE lymphadenitis. Two deep-research
  quotes attributed to PMID:37383134 (a Fas-FasL sentence and an
  IFN-alpha/2',5'-oligoadenylate sentence) were NOT present in that paper's
  abstract, so those claims were re-sourced to PMID:9839173 (Fas/perforin
  apoptosis) and PMID:19141377 (MxA/interferon dendritic-cell signature)
  whose abstracts do contain verbatim support. No GeneReviews chapter exists
  for KFD (PubMed "Kikuchi-Fujimoto GeneReviews[All Fields]" returns zero
  results), as expected for a non-Mendelian disorder; the HLA-DPB1*0202 /
  HLA-DPA1*01 signal is modeled as a germline susceptibility association
  (relationship_type RISK_FACTOR), not a causal Mendelian gene, and no
  unproven viral cause is asserted as established fact. No mechanism module was
  a genuine fit, so none is declared. No validated animal model exists (tracked
  as a KNOWLEDGE_GAP discussion).
📚

References & Deep Research

References

2
Kikuchi-Fujimoto disease: A comprehensive review.
No top-level findings curated for this source.
Kikuchi-Fujimoto disease: investigating comprehensive clinicopathological features and risk factors for recurrence.
No top-level findings curated for this source.

Deep Research

1
Claude Code
1. Disease Information
claude-haiku-4-5-20251001, claude-opus-4-8[1m] 15 citations 2026-06-30T20:57:49.686224

1. Disease Information

Overview. Kikuchi-Fujimoto disease (KFD), synonymously histiocytic necrotizing lymphadenitis (HNL), is a rare, benign, usually self-limiting cause of subacute regional (typically cervical) lymphadenopathy with fever. It was described independently in Japan in 1972 by Masahiro Kikuchi and by Yoshiro Fujimoto. Diagnosis is exclusively histopathological — the clinical and imaging picture is nonspecific and closely mimics both lymphoma and lupus lymphadenitis, so an excisional lymph-node biopsy is essential (PMC11592699, MDPI Diseases 2024; comprehensive review, PMID 37383134 / PMC10294163).

"A rare form of necrotizing lymphadenitis, is an uncommon, benign, self-limiting disorder of obscure etiology." — comprehensive review (PMID 37383134)

Key identifiers.

System ID
MONDO MONDO:0018864
Orphanet ORPHA:50918
ICD-11 4B2Y (other/unspecified) — often coded under nonspecific lymphadenitis
ICD-10 I88.1 (chronic lymphadenitis)
MeSH D020042 ("Histiocytic Necrotizing Lymphadenitis")
UMLS C0398367
GARD 6834
MedDRA 10069070

(Identifiers compiled from Orphanet/NORD/EBI-OLS listings — please re-verify MONDO/ICD mappings against the local sqlite:obo:mondo adapter before committing, per the NEC preflight in CLAUDE.md.)

Synonyms / alternative names: Kikuchi disease; Kikuchi-Fujimoto syndrome; histiocytic necrotizing lymphadenitis (HNL); necrotizing lymphadenitis; subacute necrotizing lymphadenitis.

Data provenance: Disease-level, aggregated from case series and reviews (not EHR/individual-patient registries). No dedicated large prospective registry exists.


2. Etiology

The cause is unknown. Two non-exclusive hypotheses dominate: (a) an infectious trigger (most often viral) and (b) an exaggerated, self-limited autoimmune/T-cell–mediated response in a genetically susceptible host — essentially a transient "SLE-like" reaction.

Infectious/viral hypothesis. Many agents have been associated (temporally, serologically, or by case report) but none proven causal: EBV, HSV, VZV, HHV-6/7/8, parvovirus B19, paramyxovirus, parainfluenza, rubella, CMV, and — more recently — SARS-CoV-2 infection and post-COVID-vaccination cases (PMC11592699). Support for a viral component comes from raised IFN-α and its downstream marker 2′,5′-oligoadenylate synthetase, plus tubuloreticular structures in the cytoplasm of stimulated lymphocytes/histiocytes/endothelium — an interferon-signature also seen in SLE (PMID 37383134).

"Increased levels of IFN-α and its stimulators including 2′,5′-oligoadenylate synthetase, and tubuloreticular structures in the cytoplasm of stimulated lymphocytes." — PMID 37383134

Autoimmune hypothesis. KFD is postulated to be "a self-limiting SLE-like autoimmune disorder caused by virus-infected transformed lymphocytes" triggering a cell-mediated response "to a variety of antigens in genetically susceptible people" (PMC11592699).

Genetic risk factors. No causal Mendelian gene. The principal susceptibility signal is HLA class II, notably HLA-DPA1 and HLA-DPB1 alleles that are far more common in East Asians than in Europeans. A Japanese case-control study (86 KFD patients vs 525 controls) found DPA1*01 and DPB1*0202 significantly over-represented in KFD; these alleles are common in Korea (~9.9%) and Japan (~4.5%) but rare in French (~0.4%) and Italian (~0.8%) populations — plausibly explaining the Asian predominance (summarized in PMC11592699). A 2023 report described familial KFD in HLA-partially-matched siblings both carrying DPB1*0202 (PMC10803893). RNA- and exome-sequencing efforts have begun to nominate additional candidate genes (ScienceDirect S0890850821000359).

Environmental / lifestyle risk factors: young age and Asian ancestry are the strongest demographic risks; female sex from the 30s onward. No confirmed occupational, toxic, dietary, or smoking association.

Protective factors: none established (genetic or environmental).

Gene–environment interaction (working model): an environmental antigen (virus) in a host carrying permissive HLA-DP alleles drives an over-exuberant CD8⁺ T-cell response that produces the necrotizing lesion, then self-terminates.


3. Phenotypes

For a KB entry, the core phenotype bundle (with suggested HPO terms and approximate frequencies from case series) is:

Phenotype Type Frequency Suggested HPO
Cervical lymphadenopathy (usually unilateral, posterior, tender) Sign ~virtually all cases; cervical ~85% HP:0002726 (Abnormal cervical lymph node morphology) / HP:0002716 (Lymphadenopathy)
Fever (intermittent, low-grade) Symptom ~30–55% HP:0001945 (Fever)
Leukopenia Lab ~18–50% (commonest lab abnormality) HP:0001882 (Leukopenia)
Elevated ESR Lab ~16–70% HP:0003565 (Elevated erythrocyte sedimentation rate)
Elevated LDH Lab frequent HP:0025435 (Increased circulating lactate dehydrogenase)
Anemia (chronic disease) Lab ~9–23% HP:0001903 (Anemia)
Cutaneous lesions (facial erythema, papules/plaques, morbilliform/acneiform) Sign ~30–40% HP:0000988 (Skin rash)
Night sweats Symptom common HP:0000989? (use HP:0030166 Night sweats)
Weight loss Symptom occasional HP:0001824 (Weight loss)
Splenomegaly Sign occasional (severe cases) HP:0001744 (Splenomegaly)
Hepatomegaly / elevated transaminases Sign/Lab occasional HP:0002240 / HP:0002910
Arthralgia/arthritis Symptom occasional HP:0002829 (Arthralgia)
Aseptic meningitis / CNS involvement Sign rare (extranodal) HP:0033146 (Aseptic meningitis) / HP:0002383 (Encephalitis)
Atypical lymphocytosis Lab ~25–30% HP:0031392 (Atypical lymphocytes)

Characteristics. Onset is subacute over 1–4 weeks; symptom duration averages ~2–3 weeks but can persist — one Japanese cohort reported a mean symptomatic duration of 71.5 days (PMID 39961627 / PMC12129606). Severity is usually mild–moderate and self-limited; a minority have severe systemic/extranodal disease. Course is self-limited but occasionally recurrent (see §8, §11).

"Fever (55.2%) was the most common clinical manifestation. Leukopenia (49.3%) was the commonest reported laboratory abnormality." — cervical-KFD retrospective (n=134), PMC10446312

Quality-of-life impact: generally limited given self-resolution, but the diagnostic odyssey (fear of lymphoma), painful nodes, prolonged fever, and recurrence-related anxiety are the main burdens. No KFD-specific QoL instrument exists.


4. Genetic / Molecular Information

  • Causal genes: none. KFD is not a Mendelian disorder.
  • Susceptibility loci: HLA-DPA1 (HGNC:4938) and HLA-DPB1 (HGNC:4940); risk alleles DPA1*01, DPB1*0202 (PMC11592699; familial case PMC10803893). These are germline, common population variants (association, not pathogenic mutations) — not classifiable by ACMG as pathogenic.
  • Somatic vs germline: the HLA association is germline; no recurrent somatic driver is described (KFD is non-neoplastic — clonality studies are typically negative, distinguishing it from lymphoma).
  • Modifier genes / epigenetics / chromosomal abnormalities: none established. Karyotype and clonality are normal — an important negative used to exclude lymphoma.
  • Emerging genomics: RNA-seq/exome studies are early-stage and nominate immune/interferon-pathway genes rather than a single culprit (ScienceDirect 2021).

Suggested gene descriptors (HGNC): hgnc:4938 (HLA-DPA1), hgnc:4940 (HLA-DPB1). Because casing in this repo is lowercase hgnc:.


5. Environmental Information

  • Environmental/toxic/occupational factors: none confirmed.
  • Lifestyle factors: none confirmed.
  • Infectious agents (candidate triggers, unproven): EBV (NCBITaxon:10376), HSV (10298), VZV/HHV-3 (10335), HHV-6 (10368), HHV-8 (37296), parvovirus B19 (10798), CMV/HHV-5 (10359), paramyxoviruses, parainfluenza, rubella virus (11041), SARS-CoV-2 (2697049) — associations are temporal/serological; no organism has been consistently isolated or shown causal (PMC11592699; SARS-CoV-2-triggered case, PMC10077921).

6. Mechanism / Pathophysiology

Causal chain (best-supported hypothesis):

  1. Trigger — a viral (or other) antigen in an HLA-DP–permissive host.
  2. Interferon-driven activation — type I IFN (IFN-α) signature: elevated 2′,5′-oligoadenylate synthetase, tubuloreticular inclusions, and recruitment/activation of plasmacytoid dendritic cells (pDCs) (upstream) (PMID 37383134).
  3. CD8⁺ cytotoxic T-cell response — an exaggerated T-cell–mediated immune response with marked CD8⁺ T-lymphocyte predominance.
  4. Fas–Fas-ligand apoptosis"apoptotic cell death induced by the Fas–Fas ligand system mediated by cytotoxic CD8+ cells is the principal mechanism of cellular destruction in KFD" (PMID 37383134). This produces the hallmark apoptotic karyorrhexis.
  5. Histiocytic phagocytosis — CD68⁺/CD163⁺/MPO⁺ histiocytes (many crescentic/"C-shaped" nuclei) clear apoptotic debris, forming necrotic foci without neutrophils and without well-formed granulomas (downstream) (PMC11592699).
  6. Self-limited resolution — the response terminates, node architecture recovers.

Cell types involved (suggested CL terms): - CD8⁺ cytotoxic T cellCL:0000794 - Plasmacytoid dendritic cellCL:0000784 (CD123⁺/CD303⁺; a defining infiltrate) - Myeloid/immature dendritic cellCL:0000840 (immature) / CL:0000451 - Histiocyte / macrophageCL:0000235 (CD68⁺, CD163⁺, MPO⁺, lysozyme⁺) - Immunoblast (large transformed lymphoid cell) — CL:0000653? (use B/T immunoblast as available)

Immunophenotype of the diagnostic lesional cells (Pileri/Facchetti-type analysis, PMID 19141377): the "plasmacytoid" mononuclear cells are two populations of immature dendritic cells — myeloid DCs (CD68⁺, CD1c/BDCA-1⁺, CD13/CD33⁺) and plasmacytoid DCs (CD303/BDCA-2⁺, CD123⁺), strongly MxA⁺ (IFN-α–inducible) and fascin-negative (immature).

"The morphologically distinctive mononuclear cells in lesional areas consisted of 2 populations of immature DCs: myeloid DCs …" — PMID 19141377

Suggested GO biological-process terms: - GO:0006915 apoptotic process (INCREASED) - GO:0097191 extrinsic apoptotic signaling pathway / GO:0036337 Fas signaling (INCREASED) - GO:0060337 type I interferon signaling pathway (INCREASED) - GO:0001913 T cell–mediated cytotoxicity (INCREASED) - GO:0006909 phagocytosis (INCREASED) - GO:0002456 T cell–mediated immunity (INCREASED)

Immune involvement: this is fundamentally an immune-mediated disease (cytotoxic T cell + interferon + dendritic-cell axis), sitting on a spectrum toward SLE — hence the overlapping interferon signature and the clinical progression of a subset to lupus. Molecular profiling beyond IHC (bulk transcriptomics/single-cell/proteomics) is sparse; no metabolomic or lipidomic signature is defined.


7. Anatomical Structures Affected

  • Primary: lymph nodes, especially cervical (posterior triangle, levels II–V), usually unilateral (UBERON:0000029 lymph node; UBERON:0002429 cervical lymph node). ~85% cervical.
  • Other nodal sites: axillary, supraclavicular, mesenteric, mediastinal; generalized lymphadenopathy in a minority.
  • Extranodal / secondary (organ systems): skin (UBERON:0002097; 30–40%), spleen (UBERON:0002106, splenomegaly), liver (UBERON:0002107), bone marrow (UBERON:0002371, in HLH), and CNS (UBERON:0001017 — aseptic meningitis, meningoencephalitis, cerebellar ataxia, optic neuritis).
  • Tissue/cell level: paracortical (T-zone) expansion with patchy necrosis; infiltrate of CD8⁺ T cells, immature dendritic cells, and histiocytes; B cells and plasma cells characteristically scarce (their presence suggests lupus instead).
  • Subcellular (GO cellular component): cytoplasmic tubuloreticular structures (endoplasmic-reticulum–derived; GO:0005783 endoplasmic reticulum); nuclear fragmentation (karyorrhexis) of apoptotic bodies.
  • Lateralization: predominantly unilateral cervical.

8. Temporal Development

  • Onset: young adults (mean ~30 years); subacute over days–weeks. Pediatric cases occur.
  • Course: self-limited, typically resolving in 1–4 months. Symptom duration is variable (mean ~71.5 days in one series; PMID 39961627).
  • Histologic evolution: proliferative (early) → necrotizing (peak) → xanthomatous/foamy (resolving) phases — a temporal, not just categorical, sequence (PMC11592699). The necrotizing pattern correlates with larger nodes and longer symptom duration (PMID 39961627).
  • Remission: usually spontaneous; corticosteroids hasten resolution in severe cases.
  • Recurrence: reported ~3–23% in adults (up to ~42% in some pediatric series); often multiple episodes (44% of recurrers had ≥2). Recurrence flags a higher likelihood of underlying/evolving autoimmunity (see §11).

9. Inheritance and Population

  • Epidemiology: rare; true incidence/prevalence undefined. Most reported cases are from East and Southeast Asia; uncommon in the US/Europe.
  • Age: predominantly 20–40 years (mean ~29–30).
  • Sex: historically described as female-predominant (older reports up to ~1:4 M:F), but recent large series show a near-equal or only mildly female-skewed ratio — one 112-patient Japanese cohort was 54.5% female, with male predominance up to age 20 and female predominance from the 30s onward (PMID 39961627 / PMC12129606).
  • Inheritance pattern: not inherited in a Mendelian sense; multifactorial with an HLA-DP association and rare familial clustering (PMC10803893). No penetrance/expressivity/anticipation/mosaicism/founder/carrier-frequency parameters apply.
  • Geographic distribution: endemic-appearing clustering in Asia, mirroring HLA-DPB1*0202/DPA1*01 allele frequencies.

10. Diagnostics

Definitive test: excisional lymph-node biopsy with histopathology (FNA is often nondiagnostic and risks missing lymphoma).

  • Histopathology (diagnostic hallmarks): paracortical necrotizing foci with abundant apoptotic karyorrhexis, crescentic histiocytes, immunoblasts, and plasmacytoid dendritic cells; absence of neutrophils and plasma cells; no granulomas. Three patterns: proliferative (~77%), necrotizing (~22%), xanthomatous (~1%) (PMID 39961627).
  • Immunohistochemistry: CD8⁺ T cells predominate (CD4:CD8 reversed); histiocytes CD68⁺/CD163⁺/MPO⁺/lysozyme⁺; CD123⁺ plasmacytoid DCs; scant CD20⁺ B cells; no clonal rearrangement (excludes lymphoma).
  • Laboratory: leukopenia (commonest), atypical lymphocytes, elevated ESR/CRP, elevated LDH, mild transaminitis, anemia; ANA usually negative at baseline (positivity raises suspicion of SLE).
  • Imaging (supportive, nonspecific): ultrasound — enlarged nodes with preserved echogenic hilum, no calcification; CT — homogeneous, enhancing unilateral cervical nodes (levels II–V); ¹⁸F-FDG PET/CT — multiple hypermetabolic nodes that can strongly mimic lymphoma (PMID 37383134).
  • Differential diagnosis (critical): non-Hodgkin lymphoma and Hodgkin lymphoma (most important to exclude), SLE lymphadenitis (histologically indistinguishable in ~20% — look for hematoxylin bodies, abundant plasma cells, DNA deposits), tuberculosis and other granulomatous infections, cat-scratch disease, infectious mononucleosis, HSV lymphadenitis, Sweet syndrome, histoplasmosis, syphilis, leprosy (PMC11592699).
  • Genetic/omics testing: not indicated clinically — HLA typing is a research tool, not diagnostic. No newborn/carrier/cascade screening applies.

11. Outcome / Prognosis

  • Overall prognosis: excellent — most patients recover spontaneously within months.
  • Mortality: ~2.1%, essentially confined to severe cases with hemophagocytic lymphohistiocytosis (HLH)/macrophage-activation syndrome, connective-tissue disease, or complications such as pulmonary hemorrhage, DIC, or heart failure (PMID 37383134).

"With a reported fatality rate of 2.1% and severe and fatal cases having been generally associated with hemophagocytic syndrome or connective tissue disease." — PMID 37383134

  • Recurrence: ~3–23% (adults); higher in children.
  • Progression to autoimmunity (key prognostic concern): a subset develop SLE — before, concurrent with, or after KFD (reported split ≈ KFD-before 30% / simultaneous 47% / KFD-after 23%). Recurrent KFD is an "intermediate status between transient KFD and overt autoimmune disease," associated with higher ANA positivity (57% vs 7%) and lower C4 (PMID 39961627). Long-term follow-up with ANA monitoring is recommended.
  • Prognostic factors: ANA positivity, low complement (C4), extranodal/CNS involvement, HLH, and necrotizing histology (larger nodes, longer course) predict more severe/protracted or recurrent disease.
  • Complications: HLH/MAS, aseptic meningitis/meningoencephalitis, cerebellar ataxia, optic neuritis, myocarditis, hepatitis, uveitis — all uncommon.

12. Treatment

No approved disease-specific therapy; management is empirical and largely supportive — the disease self-resolves (PMC11592699; PMID 37383134).

Line Intervention Notes Suggested MAXO/NCIT
Mild disease NSAIDs / analgesics / antipyretics Symptom control (fever, node pain) MAXO:0000058 (NSAID therapy) / NCIT:C15986 Pharmacotherapy + CHEBI agent
Moderate–severe / extranodal / relapsing Systemic corticosteroids (e.g., prednisolone) Rapid symptom resolution; reserved for severe/extranodal disease NCIT:C15986 Pharmacotherapy + therapeutic_agent NCIT:C2322 Corticosteroid (or CHEBI prednisolone)
Recurrent / steroid-dependent / autoimmune-leaning Hydroxychloroquine Immunomodulatory; used in recurrent/lupus-associated cases NCIT:C15986 + CHEBI:5801 (hydroxychloroquine)
Severe/refractory or HLH IVIG, other immunomodulators; HLH-directed therapy Case-based MAXO:0000841 (immunoglobulin therapy) / supportive care MAXO:0000950
Supportive Supportive care Hydration, monitoring MAXO:0000950 supportive care
  • Pharmacogenomics: none established for KFD.
  • Advanced therapeutics (gene/cell/RNA/targeted/immuno): not applicable — no targeted or biologic therapy is standard.
  • Surgery: limited to diagnostic excisional biopsy; not therapeutic (MAXO:0000004 surgical procedure).
  • Clinical trials: essentially none of note; a historical observational study exists (NCT00172445, "Clinical Studies of Kikuchi's Disease"). No modern interventional RCTs.
  • Response: corticosteroids reliably shorten severe episodes; overall outcomes are excellent regardless.

13. Prevention

  • Primary prevention: none — cause unknown, so no vaccine or risk-factor modification.
  • Secondary prevention / early detection: the practical "prevention" target is early lymph-node biopsy to avoid misdiagnosis as lymphoma and unnecessary chemotherapy, and post-diagnosis surveillance for SLE (periodic ANA/complement).
  • Tertiary prevention: monitor and promptly treat recurrences, HLH, and evolving autoimmunity.
  • Immunization / public-health / behavioral / prophylaxis / genetic counseling: not applicable (non-heritable, non-communicable).

14. Other Species / Natural Disease

  • Taxonomy: KFD is described only in humans (NCBITaxon:9606).
  • Natural animal disease: none reported — no recognized veterinary/wildlife counterpart in OMIA or veterinary literature.
  • Orthologous genes: the implicated HLA-DP loci belong to the MHC class II system, which has orthologues across mammals, but no cross-species KFD phenotype is documented.
  • Zoonotic / cross-species transmission: not applicable (KFD is not an infection).

15. Model Organisms

  • Animal models: none validated. There is no established mouse, rat, zebrafish, or other in-vivo model that recapitulates KFD. This is a genuine knowledge gap — appropriate for a KNOWLEDGE_GAP discussion node in the KB entry.
  • In-vitro / ex-vivo systems: mechanistic work relies on human lymph-node tissue (IHC, in-situ apoptosis assays, interferon-marker studies) rather than engineered models.
  • Implication for curation: all mechanistic evidence should be tagged HUMAN_CLINICAL or IN_VITRO (tissue-based); do not tag any KFD evidence as MODEL_ORGANISM, since no animal model data exist.

Curation Summary — high-confidence anchors for the KB entry

  • Identity: MONDO:0018864 / ORPHA:50918 / MeSH D020042; synonym "histiocytic necrotizing lymphadenitis."
  • Core pathophysiology edge chain: viral/antigen trigger → type I interferon activation + pDC recruitment → exaggerated CD8⁺ cytotoxic T-cell response → Fas–FasL apoptosis (karyorrhexis) → histiocytic phagocytosis/necrosis (no neutrophils, no granulomas) → self-limited resolution.
  • Genetics: HLA-DPA1*01 / HLA-DPB1*0202 susceptibility (association only).
  • Phenotype core: cervical lymphadenopathy (HP:0002716/HP:0002726) + fever (HP:0001945) + leukopenia (HP:0001882) + elevated ESR (HP:0003565) + elevated LDH (HP:0025435).
  • Prognosis: self-limited, ~2.1% mortality (via HLH/CTD); recurrence 3–23%; SLE overlap is the defining long-term concern.
  • Treatment: NSAIDs → corticosteroids → hydroxychloroquine/IVIG; supportive.

Priority PMIDs to fetch & snippet-validate before committing

  • PMID 37383134 — Kikuchi-Fujimoto disease: a comprehensive review (interferon mechanism, Fas-FasL, 2.1% mortality, imaging).
  • PMID 39961627 — clinicopathological features & recurrence risk factors (subtype %, recurrence 23%, ANA/C4).
  • PMID 19141377 — immature dendritic-cell phenotype of lesional cells (CD123, CD303, MPO, MxA, fascin-neg).
  • Archives of Pathology & Lab Medicine 2018;142(11):1341 (Perry & Choi) — authoritative pathology review.
  • MDPI Diseases 2024 case series (PMC11592699) and the HLA familial case (PMC10803893).

⚠️ Follow the dismech SOP: run just fetch-reference PMID:37383134 (etc.), then confirm each snippet: is an exact substring of the cached abstract before validating — several quotes above are paraphrase-adjacent and must be tightened to verbatim abstract text. Re-verify the MONDO/ICD-11 mappings against the local ontology adapter per the NEC preflight.


Sources: - Kikuchi-Fujimoto disease: A comprehensive review — PMID 37383134 / PMC10294163 - Kikuchi–Fujimoto Disease: A Case Series and Review — PMC11592699 (MDPI Diseases 2024) - Clinicopathological features and risk factors for recurrence — PMID 39961627 / PMC12129606 (Histopathology 2025) - Retrospective study of 134 cervical KFD patients — PMC10446312 - Lesional cells exhibit an immature dendritic cell phenotype — PMID 19141377 - KFD in HLA partially-matched siblings (familial susceptibility) — PMC10803893 - Genes associated with KFD via RNA/exome sequencing — ScienceDirect 2021 - SARS-CoV-2 triggering KFD — PMC10077921 - KFD + SLE + HLH case report — PMC6551871 - Kikuchi-Fujimoto Disease: A Review — Arch Pathol Lab Med 2018 - Orphanet ORPHA:50918 · NORD MONDO listing · GARD 6834 - StatPearls: Kikuchi-Fujimoto Disease — NBK430830