title: Association between cytotoxic T-lymphocyte associated protein 4 gene +49 A/G polymorphism and chronic infection with hepatitis B virus: a meta-analysis.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Hangdi
authors.initials: H
authors.lastname: Xu
authors.forename: Mingfei
authors.initials: M
authors.lastname: Zhao
authors.forename: Jiliang
authors.initials: J
authors.lastname: He
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
mesh_terms: D000483:Alleles; D060908:CTLA-4 Antigen / Q000235:genetics* / Q000276:immunology; D016022:Case-Control Studies; D015870:Gene Expression; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006515:Hepatitis B virus / Q000502:physiology; D019694:Hepatitis B, Chronic / Q000235:genetics* / Q000276:immunology / Q000821:virology; D006801:Humans; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012306:Risk; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism* / Q000821:virology; D014779:Virus Replication
chemical_list: D060908:CTLA-4 Antigen
keywords: CTLA4; Chronic hepatitis B infection; HBV; cytotoxic T-lymphocyte associated protein 4; meta-analysis; single nucleotide polymorphism