title: Lack of association between cytotoxic T-lymphocyte antigen-4+49A/G polymorphism and psoriasis and vitiligo: A meta-analysis of case-control studies.
abstract: BACKGROUND
  Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a critical negative regulator of T-cell activation and proliferation. Several studies have assessed the association between CTLA-4+49A/G polymorphism and psoriasis and vitiligo, but the results are inconsistent.
  
  
  OBJECTIVE
  This study was conducted to examine the association between CTLA-4+49A/G polymorphism and psoriasis and vitiligo susceptibility.
  
  
  METHODS
  The PubMed, Embase, and China National Knowledge Infrastructure (CNKI) databases were searched according to predefined criteria for all relevant studies published prior to July 3, 2014. Odds ratios (ORs) with 95% confidence intervals (CIs), and heterogeneity and publication bias tests were performed to estimate the strength of the association.
  
  
  RESULTS
  Fourteen studies comprising six on psoriasis (700 cases, 781 controls) and eight on vitiligo (1514 cases, 2049 controls) were included. Overall, no significant association was detected between CTLA-4+49A/G polymorphism and psoriasis. There was still no significant relationship when the studies were limited to ethnicity (Asian and Caucasian), HWE or heterogeneity, except the limitation to heterogeneity in the dominant (OR=0.69, 95% CI=0.51-0.93, I(2)=0.0%) and additive (OR=0.69, 95% CI=0.48-0.98, I(2)=0.0%) models, and the limitation to both heterogeneity and HWE in the dominant model (OR=0.68, 95% CI=0.48-0.98, I(2)=0.0%). Both overall and subgroup analyses based on ethnicity, genotype frequencies, and heterogeneity also failed to demonstrate an association between CTLA-4+49A/G polymorphism and vitiligo.
  
  
  CONCLUSIONS
  CTLA-4+49A/G polymorphism may not contribute to psoriasis and vitiligo susceptibility, but further well-designed studies with large sample size are warranted to confirm this conclusion.
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Jingyao
authors.initials: J
authors.lastname: Liang
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Sanquan
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Luo
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Tian
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Tian
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: Institute of Dermatology, Guangzhou Medical University, Guangzhou 510095, PR China; Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, PR China. Electronic address: gzpfbfzs@yahoo.com.
authors.forename: Xibao
authors.initials: X
authors.lastname: Zhang
mesh_terms: D060908:CTLA-4 Antigen / Q000235:genetics*; D016022:Case-Control Studies; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D011565:Psoriasis / Q000235:genetics*; D014820:Vitiligo / Q000235:genetics*
chemical_list: D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human
keywords: Cytotoxic T-lymphocyte antigen-4; Meta-analysis; Polymorphism; Psoriasis; Vitiligo