Objective: to study the association between interleukin-4 receptor α chain (IL-4RA) Q576R polymorphisms and bronchial asthma susceptibility by Meta-analysis.
Methods: four medical databases, including Pubmed, Embase, CNKI and Wanfang, were searched for the case-control studies about the IL-4RA polymorphisms and bronchial asthma susceptibility. Odds ratios (OR) of IL-4RA Q576R genotype distributions in asthma patients against healthy controls were analyzed in both RR vs QR + QQ model and QR + RR vs QQ model. Analyses were performed for asthma in general and for subgroups based on the atopy status of the asthma population. The sensitivity analysis and the publication bias tests were conducted.
Results: fifteen case-control studies, with 2675 asthma cases, 1202 atopic asthma cases and 331 nonatopic asthma cases respectively, were identified and all control group genotype frequencies were consistent with Hardy-Weinberg equilibrium. In genotype RR vs QR + QQ model no heterogeneity among the studies was found, while in genotype QR + RR vs QQ model, heterogeneity among these studies was found. These studies were analyzed by fixed-effect model (RR vs QR + QQ model) or random-effect model (QR + RR vs QQ model). The pooled odds ratio of IL-RA Q576R genotype RR vs QR + QQ was 2.02 (95%CI: 1.53 - 2.66), and the pooled odds ratio in this model in the atopic asthma subgroup was 2.26 (95%CI: 1.47 - 3.49), while the pooled odds ratio (QR + RR vs QQ model) was 1.02 (95%CI: 1.06 - 1.53).
Conclusion: a meta-analysis of results from case-control studies strongly supports the conclusion that IL-4RA Q576R polymorphisms impart a modest yet significant risk for asthma.