Association between CTLA-4 exon-1 +49A>G polymorphism and primary biliary cirrhosis risk: a meta-analysis

CTLA-4 exon-1 +49A>G polymorphisms have been reported to influence the risk for primary biliary cirrhosis in many studies; however, the results still remain controversial and ambiguous. The aim of this study was to determine more precise estimations for the relationship between CTLA-4 exon-1 +49A>G polymorphisms and the risk for primary biliary cirrhosis.

Electronic searches for all publications were conducted on associations between this variant and breast cancer in several databases through November 2010. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association. Eight studies were identified including 2151 cases and 2214 controls.

Overall, there were no significant associations between CTLA +49G>A polymorphism and primary biliary cirrhosis risk (codominant model: GA vs. AA OR=1.190, 95% CI=0.818-1.732; GG vs. AA OR=1.153, 95% CI=0.858-1.550; dominant model: OR=1.181, 95% CI=0.873-1.599; and recessive model: OR=1.148; 95% CI=0.903-1.459). In the subgroup analysis by ethnicity, a significantly increased risk was found for Asians (GG vs. AA OR=1.873; 95% CI=1.202-2.921) and recessive model (OR=1.758; 95% CI = 1.271-2.433). In the stratified analysis by control sources, significant association were observed in population-based studies (GA vs. AA OR=1.432; 95% CI=1.078-1.902).

This meta-analysis suggests that the CTLA-4 +49G>A polymorphism may be a risk factor for primary biliary cirrhosis in Asians.