Complement C5 Gene Confers Risk for Acute Anterior Uveitis

PURPOSE. Polymorphisms in the genes encoding C3 and C5 are associated with several immune-mediated diseases. However, the association of C3 and C5 SNPs with acute anterior uveitis (AAU) has not yet been investigated and was the purpose of the study described. METHODS. Genotyping was performed for six SNPs in C3 and four SNPs in C5 in 395 AAU patients with ankylosing spondylitis (AS), 397 AAU patients without AS, and 597 healthy controls by PCR-restriction fragment length polymorphism (PCR-RFLP) or TaqMan SNP assay. The mRNA expression was detected by real-time PCR. Cytokine production and total C5 serum concentrations were measured by ELISA. RESULTS. The frequency of the GG genotype of rs2269067 in C5 was increased in AAU patients with or without AS compared to controls (Pc = 4.0 x 10(-5), odds ratio [OR] = 1.94 and Pc = 9.4 x 10(-5), OR = 1.89, respectively). The mRNA and serum concentrations of C5 were significantly increased in rs2269067 GG cases as compared to that in CG or CC cases (P = 0.012, P = 0.002; P = 0.021, P = 0.006, respectively). An increased production of interleukin-17 was observed in rs2269067 GG cases compared to CG or CC cases (P = 5.1 x 10(-4), P = 1.4 x 10(-4), respectively). CONCLUSIONS. The C5 rs2269067 GG genotype confers risk for AAU in a Chinese population and is associated with an elevated C5 serum concentration and an increased IL-17 production.