Immunopathogenesis of Behçet's disease and treatment modalities

Introduction: Behçet's disease (BD) is an auto-inflammatory disease, primarily characterized by recurrent painful mucocutaneous ulcerations. Methods: A literature search was performed to write a narrative review into the pathogenesis and current treatment options of BD. Results: The pathogenesis of BD remains to be elucidated, but is considered a genetically primed disease in which an external trigger causes immune activation resulting in inflammatory symptoms. GWAS data show an association between multiple genetic polymorphisms (HLA-B51, ERAP1, IL10 and IL23R-IL12RB2) and increased susceptibility to BD. Bacteria as streptococci, an unbalanced microbiome or molecular mimicry trigger the inflammation in BD. Increased production or responsiveness of pro-inflammatory components of the innate immune response (TLR, neutrophils, NK-cells or γδ T-cells) to these triggers may be a crucial step in the pathogenesis of BD. Additionally to an increased autoinflammatory response there is evidence of a dysregulated adaptive immune system, with a disturbed Th1/Th2 balance, expansion of Th17 cells and possibly a decrease in regulatory T cells, resulting in a surplus in pro-inflammatory cytokines. The inflammation causes a typical clinical phenotype including orogenital ulcerations, uveitis and skin lesions. Treatment is aimed at the aberrations found in the innate (neutrophils and γδ-T cells) and adaptive immune system (TNF-α, INF-γ, IL-1), directed at organ involvement and individualized based on patient characteristics. Conclusion: We presented an extensive review into the pathogenesis and treatment options of BD.