Lack of association between CTLA-4+49A/G and -318C/T polymorphisms and Behcet's disease risk: a meta-analysis

Objective. To more precisely determine whether there is a significant association of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) gene polymorphisms with the susceptibility for Behcet's disease. Methods. Eight studies that included data from 7 articles were identified using PubMed, Embase, Chinese Biomedical Literature Database (CBM), and Chinese National Knowledge Infrastructure (CNKI) published before March 2012. Meta-analysis was performed for two CTLA-4 gene polymorphisms, +49A/G (rs231775) and 318C/T (rs5742909). Statistical analyses were performed using software Review Manager (version 5.1) and Stata (version 11.0). The pooled odds ratio (OR) with 95% confidence interval (95%CI) were presented. Results. Overall, no significant association was detected in all genetic models when all studies were pooled into the meta-analysis (for +49A/G polymorphism: A vs. G, OR=1.173, 95% CI=0.790-1.743; A/A vs. A/G+GIG, OR=1.422, 95% CI-0.718-2.814; A/A+A/G vs. GIG, OR=1.421, 95% CI=0.729-2.767; and for -318C/T polymorphism: C vs. T, OR=1.051, 95% CI=0.844-1.307; C/C vs. T/T+C/T, OR=1.154 95% CI=0.891-1.495, C/C+C/T vs. T/T, OR=1.044, 95% CI=0.301-3.617). Furthermore, in the subgroup analysis by ethnicity, there was also lack of evidence for the association in Turkish patients. Conclusion. Our study failed to provide evidence for the genetic association between CTLA-4 +49A/G and -318C/T polymorphisms with Behcet's disease based on currently available evidence from literature. Further confirmations in large and well-designed studies including other CTLA-4 gene polymorphisms are needed.