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 Behçet'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 (Pac) = 0.006, odds ratio (OR) = 1.98, 95% confidence interval (CI) 1.38, 2.83; = 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 ( = 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.