title: Toll-like receptor -1, -2, and -6 polymorphisms and pulmonary tuberculosis susceptibility: a systematic review and meta-analysis.
abstract: BACKGROUND
  A large number of studies have investigated whether polymorphisms in the Toll-like receptor (TLR) genes are implicated in susceptibility to tuberculosis (TB) in different populations. However, the results are inconsistent and inconclusive.
  
  
  METHODS
  A literature search was conducted using the PubMed, EMBASE, Medline (Ovid), ISI Web of Knowledge and Chinese National Knowledge Infrastructure (CNKI). A meta-analysis on the associations between the TLR1 G1805T, TLR2 T597C, T1350C, G2258A, and TLR6 C745T polymorphisms and TB risk was carried out by comparison using different genetic models.
  
  
  RESULTS
  In total, 16 studies from 14 articles were included in this review. In meta-analysis, significant associations were observed between the TLR2 2258AA (AA vs. AG+AG, OR 5.82, 95% CI 1.30-26.16, P = 0.02) and TLR6 745TT (TT vs. CT+CC, OR 0.61, 95% CI 0.39-0.97, P = 0.04) polymorphisms and TB risk. In the subgroup analysis by ethnicity, Africans and American Hispanic subjects with the TLR1 1805T allele had an increased susceptibility, whereas Asian and European subjects with the TLR2 2258A allele had an increased susceptibility to TB.
  
  
  CONCLUSIONS
  The meta-analysis indicated that TLR2 G2258A is associated with increased TB risk, especially in Asians and Europeans. TLR1 G1805T is associated with increased TB in Africans and American Hispanics. TLR6 C745T is associated with decreased TB risk. Our systematic review and meta-analysis reported an interesting preliminary conclusion, but this must be validated by future large-scale and functional studies in different populations.
authors.affiliation: Institute of Cell Biology, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Tingting
authors.initials: T
authors.lastname: Jiang
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Yang
authors.forename: Yun
authors.initials: Y
authors.lastname: Xue
authors.forename: Chong
authors.initials: C
authors.lastname: Wang
authors.forename: Jiyan
authors.initials: J
authors.lastname: Liu
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhongliang
authors.initials: Z
authors.lastname: Chen
authors.forename: Mengyuan
authors.initials: M
authors.lastname: Zhao
authors.forename: Ji-Cheng
authors.initials: JC
authors.lastname: Li
mesh_terms: D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D011110:Polymorphism, Genetic; D051194:Toll-Like Receptor 1 / Q000235:genetics; D051195:Toll-Like Receptor 2 / Q000235:genetics; D051216:Toll-Like Receptor 6 / Q000235:genetics; D051193:Toll-Like Receptors / Q000235:genetics*; D014397:Tuberculosis, Pulmonary / Q000235:genetics*
chemical_list: C495342:TLR2 protein, human; C495368:TLR6 protein, human; D051194:Toll-Like Receptor 1; D051195:Toll-Like Receptor 2; D051216:Toll-Like Receptor 6; D051193:Toll-Like Receptors