Behçet's disease
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Hamid Qazi, MD, BSc [2]
Synonyms and keywords: Behcet disease; Behçet syndrome; oculobuccogenital syndrome; Behçet's Syndrome
- Geographic origins: Behçet’s syndrome historically occurred in regions along the ancient Silk Road, which stretched from the Mediterranean through the Middle East to East Asia. This geographic distribution has shaped the understanding of its epidemiology
- Prevalence patterns: The highest prevalence has been reported in Turkey (420 per 100,000 persons), with decreasing frequency toward Northern Europe and the United States. Migration studies also highlighted that immigrants from high-prevalence regions carry increased—but still lower than native—risks
- Recognition as a syndrome: Over the last 20 years, several discoveries have reshaped the understanding of Behçet’s disease. It has shifted from being considered a clinical curiosity to being classified as a primary systemic vasculitis affecting veins and arteries of all sizes. This change reflects the broader spectrum of signs and symptoms recognized and the prognostic implications for patients
- Early genetic insights: The first genetic association identified was with HLA-B*51, discovered decades ago. Later, genome-wide association studies and sequencing technologies revealed multiple additional genes, leading to new classification schemes and insights into immune dysregulation
- Evolution of classification criteria: Diagnostic and classification approaches have evolved—from the 1990 International Study Group (ISG) criteria, which required recurrent oral ulcers plus two additional findings, to the 2014 International Criteria for Behçet’s Disease (ICBD), which introduced a point-based system incorporating neurologic and vascular involvement. These refinements reflect recognition of the disease’s multisystemic nature
1990 International Study Group (ISG) Classification
Mandatory criterion:
Recurrent oral ulceration (≥3 times in 1 year).
Plus two or more of the following:
Genital ulceration.
Eye lesions (anterior or posterior uveitis, vitreous cells, or retinal vasculitis).
Skin lesions (erythema nodosum, pseudofolliculitis, or papulopustular lesions).
Positive pathergy test.
Sensitivity: 81–85%.
Specificity: 96%.
2014 International Criteria for Behçet’s Disease (ICBD)
A point-based system:
Recurrent oral ulceration → 2 points.
Genital ulceration → 2 points.
Ocular lesions → 2 points.
Skin lesions → 1 point.
Vascular manifestations → 1 point.
Neurologic manifestations → 1 point.
Positive pathergy test → 1 point (optional).
Classification requires ≥4 points.
Sensitivity: 94–95%.
Specificity: 91–92%.
Genetic Predisposition
Behçet’s syndrome develops in genetically predisposed hosts after exposure to environmental triggers.
The first genetic association was with HLA-B*51, particularly HLA-B*51:01, which increases disease risk nearly sixfold.
Genome-wide association studies (GWAS) have since revealed additional key genes:
ERAP1 (antigen processing, interacts with HLA-B*51).
IL23R–IL12RB2, STAT4, IL10 (T-cell polarization toward Th1 and Th17 responses).
KLRC4 (NK cell regulation).
CCR1–CCR3 (cell chemotaxis).
Other implicated genes include TNFAIP3 (A20 haploinsufficiency), MEFV (familial Mediterranean fever), and TLR4/NOD2/FUT2, linking Behçet’s to autoinflammatory syndromes.
Epigenetic changes, such as aberrant DNA methylation and histone modifications in immune cells, further amplify susceptibility .
Environmental and Microbial Triggers
Proposed triggers include:
Microorganisms (e.g., Streptococcus species, HSV-1).
Dietary factors (histamine-releasing foods such as citrus, nuts, and cheese).
Poor oral hygiene and stress.
Studies show gut and salivary microbiome dysbiosis, leading to abnormal antigen repertoires that may drive immune responses .
Immune Dysregulation
Adaptive immunity:
CD4+ T-helper lymphocytes differentiate into Th1 (producing TNF-α, IFN-γ) and Th17 (producing IL-17, IL-23) subsets.
There is diminished regulatory T-cell activity, further tipping the balance toward inflammation.
CD8+ T cells and natural killer (NK) cells also contribute to cytotoxicity.
Innate immunity:
Neutrophils are the main infiltrating cell type in lesions.
They generate excessive reactive oxygen species (ROS) and release neutrophil extracellular traps (NETs), promoting vascular inflammation and thrombosis.
Key inflammatory pathway:
The NF-κB pathway is upregulated in antigen-presenting cells, neutrophils, and T cells, amplifying proinflammatory cytokine production .
Histopathology
Biopsies often show:
Leukocytoclastic vasculitis.
Neutrophilic or lymphocytic perivascular infiltrates.
Microvascular thrombi.
Neutrophilic dermal infiltrates.
Genetic Predisposition
Behçet’s syndrome develops in genetically predisposed hosts after exposure to environmental triggers.
The first genetic association was with HLA-B*51, particularly HLA-B*51:01, which increases disease risk nearly sixfold.
Genome-wide association studies (GWAS) have since revealed additional key genes:
ERAP1 (antigen processing, interacts with HLA-B*51).
IL23R–IL12RB2, STAT4, IL10 (T-cell polarization toward Th1 and Th17 responses).
KLRC4 (NK cell regulation).
CCR1–CCR3 (cell chemotaxis).
Other implicated genes include TNFAIP3 (A20 haploinsufficiency), MEFV (familial Mediterranean fever), and TLR4/NOD2/FUT2, linking Behçet’s to autoinflammatory syndromes.
Epigenetic changes, such as aberrant DNA methylation and histone modifications in immune cells, further amplify susceptibility .
Environmental and Microbial Triggers
Proposed triggers include:
Microorganisms (e.g., Streptococcus species, HSV-1).
Dietary factors (histamine-releasing foods such as citrus, nuts, and cheese).
Poor oral hygiene and stress.
Studies show gut and salivary microbiome dysbiosis, leading to abnormal antigen repertoires that may drive immune responses .
Immune Dysregulation
Adaptive immunity:
CD4+ T-helper lymphocytes differentiate into Th1 (producing TNF-α, IFN-γ) and Th17 (producing IL-17, IL-23) subsets.
There is diminished regulatory T-cell activity, further tipping the balance toward inflammation.
CD8+ T cells and natural killer (NK) cells also contribute to cytotoxicity.
Innate immunity:
Neutrophils are the main infiltrating cell type in lesions.
They generate excessive reactive oxygen species (ROS) and release neutrophil extracellular traps (NETs), promoting vascular inflammation and thrombosis.
Key inflammatory pathway:
The NF-κB pathway is upregulated in antigen-presenting cells, neutrophils, and T cells, amplifying proinflammatory cytokine production .
Histopathology
Biopsies often show:
Leukocytoclastic vasculitis.
Neutrophilic or lymphocytic perivascular infiltrates.
Microvascular thrombi.
Neutrophilic dermal infiltrates.
NOTOC Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3] Template:DMAKKAR
Differentiating Behçet’s Disease from Other Diseases
Behçet’s syndrome has no single pathognomonic biomarker or histologic feature, making differential diagnosis critical. Because its manifestations overlap with many autoimmune, infectious, and inflammatory conditions, clinicians must rule out these alternatives based on clinical presentation, laboratory, imaging, and histopathologic data .
- Skin, Mucosal, and Articular Manifestations
- Oral ulcers: Can mimic recurrent aphthous stomatitis, PFAPA (periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis), pemphigus, lichen planus, relapsing polychondritis, MAGIC syndrome, celiac disease, inflammatory bowel disease, systemic lupus erythematosus, or nutritional deficiencies (iron, zinc, folate, vitamins B1, B6, B12).
- Genital ulcers: May resemble herpes simplex virus infection, sexually transmitted diseases, inflammatory bowel disease, A20 haploinsufficiency, MAGIC syndrome, or mevalonate kinase deficiency.
- Skin lesions (erythema nodosum): Must be distinguished from bacterial infections (streptococcus, tuberculosis, leprosy, yersiniosis), drug reactions (oral contraceptives, penicillins, sulfonamides), inflammatory bowel disease, Takayasu’s arteritis, sarcoidosis, or malignancy.
- Arthritis/oligoarthritis: Can overlap with spondyloarthropathies or arthritis related to inflammatory bowel disease.
- Ocular Manifestations
- Uveitis: Differential includes infections (herpes viruses, CMV, tuberculosis, syphilis), sarcoidosis, multiple sclerosis, B27-associated anterior uveitis, and Vogt–Koyanagi–Harada syndrome.
- Vascular Manifestations
- Deep-vein thrombosis: May mimic antiphospholipid antibody syndrome, inflammatory bowel disease, connective-tissue diseases, myeloproliferative disorders, or inherited thrombophilias.
- Artery aneurysms: Can be seen in infections, Takayasu’s arteritis, or relapsing polychondritis.
- Neurologic Manifestations
- Parenchymal CNS lesions: Must be differentiated from infections (tuberculosis, herpes, listeriosis), multiple sclerosis, sarcoidosis, primary CNS lymphoma, and histiocytosis.
- Gastrointestinal Manifestations
- GI ulcerations: Frequently overlap with Crohn’s disease, ulcerative colitis, NSAID-induced colitis, and infectious colitis.
Diagnosis
Diagnostic Study of Choice | History and Symptoms | Physical Examination | Laboratory Findings | Electrocardiogram | X Ray | CT | MRI | Echocardiography or Ultrasound | Other Imaging Findings | Other Diagnostic Studies
Treatment
Medical Therapy | Primary Prevention| Secondary Prevention | Surgery | Cost-Effectiveness of Therapy | Future or Investigational Therapies
Case Studies
External links
- Behçet's Disease Resource Guide from the National Eye Institute (NEI).
Template:Diseases of the musculoskeletal system and connective tissue de:Morbus Behçet he:תסמונת בכצ'ט nl:Ziekte van Behçet