Association of IL-12A and IL-12B gene polymorphisms with rheumatoid arthritis: a meta-analysis

The aim of our study was to investigate the association between common polymorphisms in interleukin-12 (IL-12) and rheumatoid arthritis (RA) risk using meta-analysis. A search was conducted in the PubMed database, covering all papers published by October 14, 2015. Odds ratios (OR) and 95% confidence intervals (CI) were used to evaluate the strength of this association. Publication bias was assessed with Begg's test. Overall, 6 case-control studies with 3,436 RA patients and 4,644 healthy controls were retrieved. No significant association was observed between the IL-12B rs3212227 polymorphism and RA risk in all genetic models. Similar negative observations were also detected for IL-12B rs6887695 and IL-12A rs2243115 polymorphisms. Interestingly, an increased association was found between the rs3212227 polymorphism and RA risk in the hospital-based source of control (CC vs. AA: OR = 2.13, 95% CI = 1.11-4.09; CC+CA vs. AA: OR = 2.08, 95% CI = 1.06-4.09). Overall, no obvious evidence of publication bias was detected. There had a poor evidence to confirm that IL-12B gene rs3212227 polymorphism was associated with susceptibility of RA.