The role of Toll-Like Receptor Gene Polymorphisms in Tuberculosis Susceptibility: A Systematic Review and Meta-Analysis

Susceptibility to tuberculosis (TB) infection varies in individuals and is linked to genetic variations in the toll-like receptors (TLRs) genes. The current study employed a systematic literature review and meta-analysis to describe the most prevalent single nucleotide polymorphisms (SNPs) from various TLRs and to assess the association between these polymorphisms and tuberculosis susceptibility.
The PubMed, Google Scholar, Scopus, and ISI Web of Knowledge databases were searched for all articles published before May 25, 2015, that contained the target keywords. Following the application of the inclusion and exclusion criteria, a total of 37 relevant articles were identified that examined the association between the TLRs gene polymorphism and susceptibility to tuberculosis.
A meta-analyses approach to the research determined that there is a statistically significant association between TLR1 rs4833095, TLR6 rs5743810, and TLR8 rs3788935 in the allelic model and also TLR1 rs4833095, TLR1 rs5743018, TLR2 rs5743708, TLR6 rs5743810, and TLR8 rs3761624 in the co-dominant model with increased or decreased susceptibility to tuberculosis. No associations were observed between the other TLRs polymorphisms and tuberculosis risk.
Several studies have found that host genetic factors, such as SNPs in TLRs gene, may increase an individual’s susceptibility to tuberculosis. Therefore, the identification of these SNPs is important to investigate immune responses to TB.
The present study concluded that there is an association between some polymorphisms of TLRs and tuberculosis risk. Thus, for a better understanding about the role of SNPs to TB susceptibility, additional studies on alternative TLRs SNPs are needed.