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

Abstract

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 TaqMan 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 (Pcorrected (Pcorr)=1.82×10(-5), OR=1.837; Pcorr=6.1×10(-5), OR=1.780; Pcorr=3.15×10(-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, Pcorr=5.59×10(-5), OR=1.493; Combined data, Pcorr=3.65×10(-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.

Figure 1

The relative positions of the investigated SNPs and the LD analysis of the examined SNPs of IL-10. A: The relative positions of the investigated SNPs of IL10 tested in this study (red arrows). B: An LD analysis was performed for SNPs rs1800896, rs1800871, rs1800872, rs3790622, rs3021094, and rs1554286 based on our data using Haploview software version 4.2. The number in the square indicates r² value.

Figure 2

Forest plots illustrate the association between IL-10 gene polymorphisms and BD in Chinese Han. For each study, the odds ratio (OR) and 95% confidence interval (CI) values are indicted. The size of each box is proportional to the weight of each study. The squares and horizontal lines correspond to the OR and 95% CI, and the diamond represents the summary OR and 95% CI. A: The rs1800871 T allele versus C allele. B: The rs3021094 A allele versus C allele. C: The rs3790622 T allele versus C allele.

Figure 3

The expression of different genotypes of rs1800871/IL-10 at mRNA level in a stimulated condition by LPS or anti-CD3/CD28 antibodies. A: The relative expression of IL-10 mRNA in LPS-stimulated PBMCs obtained from healthy controls with the known IL-10 rs1800871 genotype. B: The relative expression of IL-10 mRNA by anti-CD3/CD28 antibody-stimulated PBMCs obtained from healthy controls with the known IL-10 rs1800871 genotype. The y-axis represents the IL-10 mRNA relative expression level through the real-time PCR of each genotype. Data are shown as mean ± SD. PBMCs included lymphocytes, such as T, B, and NK cells (90–95%), monocytes (3%), and Dendritic cells.