Promoter polymorphism (-590, T/C) of interleukin 4 (IL4) gene is associated with rheumatoid arthritis: An updated meta-analysis

Rheumatoid arthritis (RA) is a chronic disease. It causes chronic inflammation of the joint. Recent studies suggested that interleukin 4 (IL4) contributes to susceptibility and severity of rheumatoid arthritis (RA). Especially, it was reported that promoter polymorphism (-590, T/C) of IL4 gene has been associated with susceptibility of RA. The aim of present study was to investigate whether the promoter polymorphism (-590, T/C) of IL4 gene is associated with the susceptibility of RA using meta-analysis. And in order to perform meta-analysis, comprehensive meta analysis program was used. Genetic models (co-dominant, dominant, recessive, and allele) were used to determine odds ratios (ORs), 95% confidence intervals (CIs), and P values. Nine case-control studies with case and control design were included in this meta-analysis. Overall, meta-analysis revealed a strong association with susceptibility of RA [OR = 1.303, 95% CI = 1.093-1.554, P = 0.003 in allele model (C vs. T); OR = 1.247, 95% CI = 1.054-1.474, P = 0.010 in dominant model (CC vs. CT + TT); OR = 2.148, 95% CI = 1.263-3.651, P = 0.005 in recessive model (CC + CT vs. TT)]. Our data demonstrated that promoter polymorphism (-590, T/C) of IL4 gene may be contributed to susceptibility of RA. However, more studies with a larger sample size are needed to provide more precise evidence.