Cytotoxic T-lymphocyte associated antigen 4 polymorphisms and asthma risk: a meta-analysis

A number of studies assessed the association of cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) gene polymorphisms with asthma in different populations. However, the results were contradictory. We performed a meta-analysis to examine the association between CTLA-4 polymorphisms and asthma susceptibility. Pubmed, EMBASE, HuGE Navigator, and Wanfang Database were searched. Data were extracted independently by two reviewers. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Seventeen studies involving 6378 cases and 8674 controls were included. Significant association between +49 A/G polymorphism and asthma was observed for AA vs. AG+GG (OR = 1.18, 95% CI 1.01-1.37, P = 0.04). There were no significant associations between -318 C/T, -1147 C/T, CT60 A/G, -1722 C/T, or rs926169 polymorphisms and asthma risk. This meta-analysis suggested that the +49 A/G polymorphism in CTLA-4 was a risk factor for asthma.