Association between cytotoxic T-lymphocyte associated protein 4 gene +49 A/G polymorphism and chronic infection with hepatitis B virus: A meta-analysis

Abstract

This meta-analysis determined the relationship between polymorphisms of the cytotoxic T-lymphocyte-associated protein 4 (CTLA4) gene and hepatitis B virus (HBV) clearance in chronic hepatitis B. Published studies reporting associations between CTLA4 gene +49A/G polymorphisms and chronic HBV infection were reviewed. Odds ratio (OR) and 95% confidence interval (CI) were calculated to assess the risk of persistent HBV according to genotype. Six studies, involving 1076 chronic HBV patients and 1294 controls, were included. The risk of persistent HBV in patients with a +49 GG/AG genotype decreased significantly compared with the AA genotype (OR 0.65; 95% CI 0.52, 0.82). The variant G allele was negatively associated with chronic HBV infection versus the A allele (OR 0.77; 95% CI 0.68, 0.88). When stratifying by type of study control, a significantly decreased risk was associated with CTLA4+49 variant genotypes (AG and GG) in both spontaneous recovery control group and healthy control group. Findings of this meta-analysis suggest that A at position +49 of the CTLA4 gene may significantly increase the risk of persistent HBV infection, whereas G at position +49 may positively influence virus clearance.