CD40 gene polymorphisms confer risk of Behcet's disease but not of Vogt-Koyanagi-Harada syndrome in a Han Chinese population

Objectives. Recent genetic surveys including a genome-wide association study have identified CD40 as a susceptibility gene for several autoimmune diseases. This study was designed to investigate the association of CD40 gene polymorphisms with Behcet's disease (BD) and Vogt-Koyanagi-Harada (VKH) syndrome in a Han Chinese population. Methods. Two single nucleotide polymorphisms (SNPs), rs4810485 and rs1883832, were genotyped using polymerase chain reaction-restriction fragment length polymorphism in 373 BD patients, 519 VKH patients and 402 controls. A binary logistic regression analysis was applied to assess the influence of gender on the association of CD40 polymorphisms with BD. Results. Our results showed significantly increased frequencies of the homozygous rs4810485 TT and rs1883832 TT in BD patients as compared with the controls [Bonferroni-corrected P-value for gender adjustment (P-c(a)) = 0.006, odds ratio (OR) = 1.98, 95% confidence interval (CI) 1.38, 2.83; P-c(a) = 0.012, OR = 1.73, 95% CI 1.22, 2.46, respectively]. A markedly decreased frequency of the heterozygous rs4810485 GT was observed in BD patients as compared with the controls (P-c(a) = 0.042, OR = 0.68, 95% CI 0.51, 0.90). The genotype and allele frequencies of rs4810485 and rs1883832 were not different between VKH patients and controls. Stratification analysis did not find any association between the tested SNPs and extra-ocular manifestations of both diseases. Conclusions. The results suggest that TT genotypes of rs4810485 and rs1883832 may be predisposing genotypes for BD, and that the rs4810485 GT genotype may be a protective genotype for BD. The two tested CD40 gene polymorphisms are not associated with VKH syndrome in the investigated Han Chinese population.