title: The association between CTLA-4 (+49 A/G) polymorphism and susceptibility to ankylosing spondylitis: a meta-analysis.
abstract: OBJECTIVE
  The objective of the present meta-analysis was to investigate whether or not cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) polymorphisms are associated with ankylosing spondylitis (AS) susceptibility.
  
  
  METHODS
  A systematic search was conducted from the PubMed, ENBASE, and Springer link database up to April 2014. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to assess the strength of association between CTLA-4 (+49 A/G) and AS risk. A subgroup analysis based on geographic region and a sensitivity analysis were also conducted.
  
  
  RESULTS
  Five studies were eligible for meta-analysis, including 918 cases and 845 controls. The results showed that no significant association was found between AS and CTLA-4 (+49 A/G) for the additive model (G vs. A), dominant model (GG + AG vs. AA), co-dominant model (GG vs. AA, AG vs. AA) and recessive model (GG vs. AG + AA). The OR was 1.09 (95% CI, 0.87-1.38), 1.16 (95% CI, 0.89-1.51), 1.05 (95% CI, 0.75-1.46), 1.15 (95% CI, 0.86-1.52) and 0.99 (95% CI, 0.79-1.23), respectively. Although subgroup analysis demonstrated no association between CTLA-4 (+49 A/G) polymorphisms and susceptibility to AS in Europe and Taiwan, an association was found in Iran through both the co-dominant and dominant models. Exclusion of any individual study did not alter the significance of the final outcome, excepting the result by omitting the study by Huang et al.
  
  
  CONCLUSIONS
  The present results suggest that the CTLA-4 may not be a major susceptibility locus in humans with AS. The relationship between them may be affected by different geographic populations.
authors.affiliation: Department of Orthopaedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, Beijing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Orthopaedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, Beijing, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, Beijing, China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D060908:CTLA-4 Antigen / Q000235:genetics* / Q000276:immunology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005060:Europe / Q000453:epidemiology; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010641:Phenotype; D011110:Polymorphism, Genetic; D012307:Risk Factors; D013167:Spondylitis, Ankylosing / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
chemical_list: D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human
keywords: CTLA-4; ankylosing spondylitis; meta-analysis; polymorphism