title: The regulated upon activation normal T-cell expressed and secreted (RANTES) -28C/G and -403G/A polymorphisms and asthma risk: a meta-analysis.
abstract: OBJECTIVE
  Genetic studies have revealed that the regulated upon activation normal T-cell expressed and secreted (RANTES) -28C/G and -403G/A polymorphisms are associated with asthma risk, but contradictory findings have also been reported. Therefore, we undertook a meta-analysis on this topic.
  
  
  METHODS
  The PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases were used to identify relevant studies published in the medical literature from 1990 to March 26, 2014. Nine studies (containing 2,103 cases and 2,876 controls) investigated the -28C/G polymorphism, and 11 studies (including 2,015 cases and 1,909 controls) assessed the -403G/A polymorphism.
  
  
  RESULTS
  The pooled results demonstrated that the -28C/G polymorphism was not associated with asthma risk in the overall populations (Caucasians, Asians, and a mixed population). However, in subgroup analysis according to age, the -28G allele was associated with an increased risk of asthma in children (odds ratio [OR] 1.27, 95 % confidence interval [CI] 1.03-1.57, P value for heterogeneity [P het] = 0.163, P value for the overall effect [P z] = 0.028). When we further stratified the studies performed in children on the basis of ethnicity, we found that the -28G allele was associated with an increased risk of asthma in Asian children (OR 1.28, 95 % CI 1.02-1.62, P het = 0.127, P z = 0.035), but not in Caucasian children (OR 1.20, 95 % CI 0.68-2.12, P het = 0.137, P z = 0.530). In subgroup analysis by asthma phenotype, no association between either atopic or non-atopic asthma and the -28C/G polymorphism was identified. For the -403G/A polymorphism, meta-analysis showed no association with asthma risk in the overall populations (Caucasians, Asians, and black people). In subgroup analyses by age, ethnicity, and asthma phenotype, we still did not find any association between the -403G/A polymorphism and asthma.
  
  
  CONCLUSIONS
  Current findings suggest an association between the -28G allele and asthma risk in Asian children but not in Caucasian children.
authors.affiliation: Department of Clinical Medicine, Grade 2011, Guangxi Medical University, Nanning, China.
authors.forename: Zi-Kang
authors.initials: ZK
authors.lastname: Xie
authors.forename: Hua
authors.initials: H
authors.lastname: Zhao
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.forename: Zheng-Fu
authors.initials: ZF
authors.lastname: Xie
mesh_terms: D044466:Asian People / Q000235:genetics*; D001249:Asthma / Q000175:diagnosis / Q000235:genetics*; D018946:Chemokine CCL5 / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006147:Guanine / Q000378:metabolism*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors; D044465:White People / Q000331:legislation & jurisprudence*
chemical_list: C483024:CCL5 protein, human; D018946:Chemokine CCL5; D006147:Guanine