Interleukin-4, interleukin-4 receptor, and interleukin-18 polymorphisms and rheumatoid arthritis: A meta-analysis

Objective: The aim of this study was to determine whether the functional interleukin-4 (IL-4)-590 C/T, IL-4 receptor (IL-4R) 1902 G/A, IL-18-607 C/A, and-137 G/C polymorphisms polymorphisms confer susceptibility to rheumatoid arthritis (RA). Methods: Meta-analysis was conducted on the associations between these IL-4, IL-4R, and IL-18 polymorphisms and RA. Results: A total of 12 comparative studies were included in this meta-analysis. Meta-analysis of the IL-4-590 C/T polymorphism showed an association in all study subjects and Europeans (OR for the TT genotype=2.280, 95% CI=1.315-3.952, p=0.003; OR=2.139, 95% CI=1.089-4.199, p=0.027). However, meta-analysis showed no association between RA and the IL-4R 1902 G allele in all study subjects and Europeans. Meta-analysis showed no association between RA and the IL-18-607 C allele (OR=1.159, 95% CI=0.967-1.387, p=0.110). Meta-analysis of the IL-18-137 G/C polymorphism revealed no association between RA and the IL-18-137 G/C polymorphism. Conclusions: This meta-analysis demonstrates that the IL-4-590 T/C polymorphism is associated with susceptibility to RA in Europeans, but the IL-4R+1902 G/A, IL-18-607 C/A and-137 G/C polymorphisms are not associated with RA.