title: Associations between circulating IL-17 levels and rheumatoid arthritis and between IL-17 gene polymorphisms and disease susceptibility: a meta-analysis.
abstract: OBJECTIVE
  To systematically review evidence regarding the relationship between circulating interleukin-17 (IL-17) levels and rheumatoid arthritis (RA), and associations between polymorphisms in IL-17 genes and RA susceptibility.
  
  
  METHODS
  We performed a meta-analysis of serum/plasma IL-17 levels in patients with RA and controls, and evaluated evidence of associations between the rs2275913, rs3819024, rs4711998 and rs8193036 polymorphisms inIL-17Aand the rs763780 and rs2397084 polymorphisms inIL-17Fand risk for RA.
  
  
  RESULTS
  Fourteen studies including 3118 patients with RA and 2725 controls were included. Our meta-analysis revealed that IL-17 levels were significantly higher in the RA group than in the control group (p=3.1×10-6). Subgroup analysis using sample size showed increased IL-17 levels in samples from both small (n≤100) and large (n>100) RA groups (p=1.1×10-4and p=0.008, respectively). We found evidence of associations between RA and alleles from theIL-17Ars2275913 andIL-17Frs763780 polymorphisms in Caucasians (p=0.003 and p=0.037, respectively). In addition, we found an association between RA and alleles of theIL-17Ars3819024 polymorphism in the pooled RA cohort compared with matched controls (p=0.033). However, no evidence of association was found between theIL-17Frs2397084,IL-17Ars4711998 andIL-17Ars8193036 polymorphisms and RA susceptibility.
  
  
  CONCLUSIONS
  Our meta-analysis revealed significantly higher circulating IL-17 levels in patients with RA, and found evidence of associations between theIL-17Ars2275913,IL-17Frs763780 andIL-17Ars3819024 polymorphisms and pathogenesis of RA.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea.
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea.
authors.forename: Sang-Cheol
authors.initials: SC
authors.lastname: Bae
mesh_terms: D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D020381:Interleukin-17 / Q000097:blood* / Q000235:genetics*; D008297:Male; D020641:Polymorphism, Single Nucleotide
chemical_list: D020381:Interleukin-17
keywords: IL-17; Level; Polymorphism; Rheumatoid arthritis