title: Association of Toll like receptor Asp299Gly with rheumatoid arthritis risk: a systematic review of case-control studies and meta-analysis.
abstract: OBJECTIVE
  Rheumatoid arthritis (RA) is thought to be triggered by various genetic and environmental factors. Few human epidemiologic studies demonstrated that single nucleotide polymorphisms (SNPs) in Toll-like receptor (TLR) genes are associated with RA. We aimed to evaluate the effects of TLR polymorphisms on the risk of RA pathogenesis by using a meta-analysis approach.
  
  
  METHODS
  Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, a systematic search and meta-analysis of the literature was conducted. We screened the medical literature based on keywords search in MEDLINE and EMBASE 'Toll-like receptor', 'polymorphism', and rheumatoid arthritis. Meta-analyses were performed under the random-effects model by using: (1) recessive, (2) homozygous, (3) dominant, (4) codominant and allele contrast models.
  
  
  RESULTS
  A total of 3086 cases and 3756 controls in nine studies were included in the meta-analysis. Association between TLR4 Asp299Gly and RA risk was marginally significant [OR = 0.856 (95% CI, 0.716-1.022); P = 0.086] in the homozygous model. AA and GG homozygote genotypes tended to be significant protective factors against RA risk.
  
  
  CONCLUSIONS
  Our overall analyses indicated that TLR4 Asp299Gly polymorphism might contribute to RA pathogenesis.
authors.affiliation: Department of Histology and Immunology, Faculty of Medicine Tunis, 15 Rue Djebel Lakdhar, 1007 Tunis, Tunisia. Electronic address: kalttizaoui@gmail.com.
authors.forename: Kalthoum
authors.initials: K
authors.lastname: Tizaoui
authors.affiliation: Department of Histology and Immunology, Faculty of Medicine Tunis, 15 Rue Djebel Lakdhar, 1007 Tunis, Tunisia.
authors.forename: Abir
authors.initials: A
authors.lastname: Naouali
authors.affiliation: Department of Histology and Immunology, Faculty of Medicine Tunis, 15 Rue Djebel Lakdhar, 1007 Tunis, Tunisia.
authors.forename: Wajih
authors.initials: W
authors.lastname: Kaabachi
authors.affiliation: Department of Histology and Immunology, Faculty of Medicine Tunis, 15 Rue Djebel Lakdhar, 1007 Tunis, Tunisia; Division of Pulmonology, Unit research: 12SP15, "Homeostasis and Cell Immune Dysfunction", A. Mami Hospital, Ariana, Tunisia.
authors.forename: Agnès
authors.initials: A
authors.lastname: Hamzaoui
authors.affiliation: Department of Histology and Immunology, Faculty of Medicine Tunis, 15 Rue Djebel Lakdhar, 1007 Tunis, Tunisia.
authors.forename: Kamel
authors.initials: K
authors.lastname: Hamzaoui
mesh_terms: D000483:Alleles; D001172:Arthritis, Rheumatoid / Q000235:genetics*; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D051193:Toll-Like Receptors / Q000235:genetics*
chemical_list: D051193:Toll-Like Receptors
keywords: Meta-analysis; Rheumatoid arthritis; SNPs; TLR genes; TLR4 Asp299Gly