Association of Interleukin-10 gene polymorphisms with ankylosing spondylitis.

OBJECTIVE Genetic polymorphisms of the Interleukin-10 (IL-10) promoter have been implicated in several autoimmune diseases, including seronegative spondyloarthropathies. This study investigated whether single nucleotide polymorphisms (SNPs) and haplotypes of IL-10 are associated with ankylosing spondylitis (AS), a common subtype of spondyloarthritis (SpA). METHODS The serum levels of IL-10 were measured with an enzyme-linked immunosorbent assay (ELISA). The single nucleotide polymorphisms (SNPs) at positions -1082A/G, -819C/T and -592C/A in the IL-10 gene promoter were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS 110 AS patients and 120 ethnic-matched healthy controls were included in this study. The serum levels of IL-10 were significantly higher in AS patients than healthy controls (Z=-10.9, P < 0.001). Single SNP analysis showed no significant differences in the allelic and genotypic frequencies of -592A/C between the AS patients and healthy controls. No -1082GG genotype was found in this study. An increased frequency of -1082G allele was noted in AS patients (P=0.047). In a logistic regression analysis, the -1082AG genotype was associated with an odds ratio of 1.993 (95%CI, 1.046-3.800, P=0.034) for AS. And the -819CC genotype was associated with an odds ratio of 3.125 (95%CI, 1.246-7.836, P=0.015) for AS. Furthermore, haplotype analysis revealed that GCC haplotype was associated with a significantly increased risk of AS as compared with the ATA haplotype (OR=2.19; 95% CI, 1.13-4.26; P=0.02). CONCLUSION Our results indicate that the gene haplotype of IL-10 can contribute to the susceptibility to AS in a Chinese population.