Cytokines and Behcet's disease

A functional variant of pre-miRNA-196a2 confers risk for Behcet's disease but not for Vogt-Koyanagi-Harada syndrome or AAU in ankylosing spondylitis

This study aimed to investigate the predisposition of common pre-miRNA SNPs with Behcet's disease (BD), Vogt-Koyanagi-Harada (VKH) syndrome and acute anterior uveitis (AAU) associated with ankylosing spondylitis (AS). A two-stage association study was carried out in 859 BD, 400 VKH syndrome, 209 AAU(+)AS(+) patients and 1,685 controls all belonging to a Chinese Han population. Genotyping, the expression of miR-196a and Bach1 (the target gene of miR-196a), cell proliferation, cytokine production were examined by PCR-RFLP, real-time PCR, CCK8 and ELISA. In the first stage study, the results showed significantly increased frequencies of the miR-196a2/rs11614913 TT genotype and T allele in BD patients (adjusted P(c) = 0.024, OR = 1.63; adjusted P(c) = 5.4 × 10(-3), OR = 1.45, respectively). However, no significant association of the tested SNPs with VKH and AAU(+)AS(+) patients was observed. The second stage and combined studies confirmed the association of rs11614913 with BD (TT genotype: adjusted P(c) = 6×10(-5), OR = 1.53; T allele: adjusted P(c) = 8×10(-6), OR = 1.35; CC genotype: adjusted P(c) = 0.024, OR = 0.68). A stratified analysis showed an association of the rs11614913 TT genotype and T allele with the arthritis subgroup of BD (P(c) = 5.3 × 10(-3), OR = 1.89; P(c) = 0.015, OR = 1.56, respectively). Functional experiments showed a decreased miR-196a expression, an increased Bach1 expression and an increased production of IL-1β and MCP-1 in TT cases compared to CC cases (P = 0.023, P = 0.0073, P = 0.012, P = 0.002, respectively). This study shows that a functional variant of miR-196a2 confers risk for BD but not for VKH syndrome or AAU(+)AS(+) by modulating the miR-196a gene expression and by regulating pro-inflammatory IL-1β and MCP-1 production.

Current and future treatments for Behçet's uveitis: road to remission

Behçet's disease (BD) is a multisystem inflammatory disorder of uncertain origin, although it remains defined within the spectrum of systemic immune-mediated vasculitic disorders and also represents a spectrum of putative autoimmune disease. Major symptoms include oral aphthous ulcers, genital ulcerations, skin lesions, and ocular lesions. Despite afflicting many systems, ocular complications of BD are some of the more devastating for the patient and their quality of life. Eye involvement, which affects 60-80 % of BD patients, is characterized in its more severe form by posterior or panuveitis including occlusive retinal vasculitis. While pathogenesis of BD remains complex, association with Class I MHC (HLA-B*51) predisposing to inflammation with engagement of the innate-immune system (neutrophils, NK cells), and perpetuated by the adaptive T cell responses against infectious- and/or auto-antigens. Despite the choice of conventional immunosuppressive therapies available, only recently with the advent of biologic therapy has visual prognosis and outcomes been substantially and favorably altered. For example, both interferon-α (IFN-α) and tumour necrosis factor (TNF)-α antagonists deliver promising results and for the first time improve prognosis. With IFN-α therapy, durable remissions of uveitis can be achieved and lead to drug-free remission. Similarly, anti-TNF therapy with infliximab is reported to be rapidly effective in inducing and maintaining remission. Most recently, rising evidence reports on the use of adalimumab, etanercept, and golimumab, while use of anti-interleukin (IL)-1 agents (anakinra, canakinumab, gevokizumab), IL-6 blockers (tocilizumab), and rituximab (depleting anti-CD20 antibody) is also increasing. The aim of this review is to provide evidence for the role of conventional therapies combined with evidence for advantages and disadvantages of biologic therapies in the treatment of ocular BD. Although randomized controlled trials remain sparse, evidence remains strong and enticing that biologic agents are invaluable for the treatment of sight-threatening Behçet's uveitis and makes it an exciting time for Behçet's specialists worldwide.

Association of allelic variants of factor V Leiden, prothrombin and methylenetetrahydrofolate reductase with thrombosis or ocular involvement in Behçet's disease: a systematic review and meta-analysis

Thrombosis is frequent in patients with Behçet's disease (BD), although the exact cause remains uncertain. Some single nucleotide polymorphism (SNP) (G1691A in factor V gene, also called factor V Leiden [FVL], G20210A in prothrombin gene and C677T in methyltetrahydrofolate reductase [MTHFR] gene) have been associated with thrombosis and ocular involvement in BD with controversial results.

AIM

To assess the effects of FVL, prothrombin and MTHFR SNP variants in patients with BD and thrombosis and ocular involvement by means of a systematic review and meta-analysis.

METHODS

We retrieved studies analyzing the genotype of the above-mentioned polymorphism among patients with BD. A meta-analysis was conducted in a random effects model and calculations of odds ratio (OR) and confidence intervals (CI) were done. Sensitivity analysis and tests for heterogeneity of the results were performed.

RESULTS

27 previous studies analyzed the association of BD and thrombosis with the FVL, prothrombin and MTHFR polymorphisms. A significant association was found between the possession of the AA or GA genotypes of FVL polymorphism among patients with BD and the presence of any thrombosis (OR=2.51; 95% CI: 1.68, 3.74; P<0.00001). In addition, a significant association was found between the possession of the GA or AA genotypes and the presence of BD (OR=2.67; 95% CI: 1.93. 3.72; P<0.00001) when cases with BD and healthy controls were compared. This association was not found when studies from Turkey were excluded. No association was found between prothrombin and MTHFR SNPs and thrombosis in BD, and no association between any SNP and ocular involvement was shown either.

CONCLUSIONS

Factor V Leiden could be responsible for some thrombotic events in at least Turkish patients. However, this relationship has to be demonstrated from a pathogenic point of view.