Interleukin-10 gene polymorphisms are associated with Behcet's disease but not with Vogt-Koyanagi-Harada syndrome in the Chinese Han population

Purpose: This study aimed to investigate the association of interleukin (IL)-10 gene polymorphisms with Behcet's disease (BD) and Vogt-Koyanagi-Harada (VKH) syndrome in the Chinese Han population.Methods: A two-stage association study was performed on 718 BD patients, 300 VKH patients, and 1,753 controls. Genotyping of the IL-10 gene was performed for six single nucleotide polymorphisms (SNPs), including rs1800871, rs1800872, rs1800896, rs3021094, rs3790622, and rs1554286 using PCR-restricted fragment length polymorphism or Taq-Man SNP assays. Real-time PCR was performed to test the IL-10 mRNA expression of the associated polymorphisms.Results: The first-stage result showed significantly increased frequencies of the rs1800871 T allele, rs1800872 A allele, and rs1554286 T allele in BD patients compared with controls (P-corrected (P-corr) = 1.82x10(-5), OR = 1.837; P-corr = 6.1x10(-5), OR = 1.780; P-corr = 3.15x10(-5), OR = 1.794, respectively). There was no association of the tested six SNPs with VKH syndrome. A second-stage study was therefore performed in BD patients to validate the result of the first stage, showing a significantly increased frequency of the rs1800871 T allele (Second stage, P-corr = 5.59x10(-5), OR = 1.493; Combined data, P-corr = 3.65x10(-11), OR = 1.632). Compared to the controls, an increased frequency of the rs1800871 T allele was observed in BD patients with extraocular findings, including genital ulcers, skin lesions, and a positive pathergy test. No difference was found among the mRNA expressions of IL-10 in the peripheral blood mononuclear cells (PBMCs) of controls with different genotypes of rs1800871 after stimulation of lipopolysaccharide (LPS) or anti-CD3/CD28 antibodies.Conclusions: The findings showed that IL-10 is a risk gene for BD but not for VKH syndrome