Cytokines and Behcet's disease.

Behcet's Disease (BD) is a systemic vasculitis of unknown etiology. Increasing studies find that a sophisticated interlacing cytokine network is closely implicated in the onset, evolution and even organ damages of the disease. Cytokines involved can be categorized as Th1 type, Th2 type, Th17 type, chemokines and other proinflammatory cytokines, etc. The vicious cycle of cytokine network plays a substantial role in the disease pathogenesis and even in organ lesions, and might be disorganized by blocking one of the key links of the cytokines, which in turn may provide essential clues to outlook the target therapy regimen of cytokine agents in BD. There have been a number of case reports of the positive efficacies of cytokine (and cytokine blocker) agents including Infiximab (Human murine chimeric Anti-TNF α monoclonal antibody), Anakinra (recombinant, non-glycosylated human IL1 receptor antagonist) etc in BD. IFN-α had been used clinically in treating BD with uveitis with beneficial efficacy ever since the 1980s. The studies to date suggested that IL6, IP10 are involved in BD with nervous system lesions, IL17, IL18 are relevant to the superimposed uveitis in patients with BD. Some cytokines i.e. IL8, RANTES, MIP-1α are associated with the disease activity, whereas others are exemplified by that of IL10, whose level shows negative relevance to the disease activity, might be potentially cytokine of protecting effect. According to the related genetic study, the SNPs of numerous cytokines including IL1, TNFα, IFNγ, IL12, and IL18 are pertinent to BD. The recent GWAS (Genome Wide Association Studies) demonstrated that SNPs in the IL10 and IL23R-IL12RB2 region are associated with the disease. Most studies nowadays are confined within the cytokines in the peripheral blood levels, owing to the potentially significant roles of certain cytokines in local lesions. It warrants further in-depth study to address this issue. Moreover, it deserves multi-centre study considering the unique geographical "silk road" display picture of the disease.