Association of Polymorphisms in Toll-Like Receptors 4 and 9 with Risk of Pulmonary Tuberculosis: A Meta-Analysis

BACKGROUND: Findings regarding the association of the single-nucleotide polymorphisms (SNPs) rs4986790 and rs4986791 in Toll-like receptor 4 and rs187084, rs574386, and rs352139 in Toll-like receptor 9 (TLR9) with pulmonary tuberculosis (PTB) susceptibility are inconsistent. We conducted a meta-analysis to systematically summarize and clarify the association between these SNPs and PTB susceptibility.
MATERIAL AND METHODS: A systematic literature search for relevant studies up to December, 2014 was performed in PubMed, EMBASE, Web of Science, Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases. Information was gathered from each eligible study. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to pool the effect size.
RESULTS: Finally, a total of 16 case-control studies on these polymorphisms were enrolled in this meta-analysis. The meta-analysis results suggest there was no association between these polymorphisms and PTB risk PTB risk in all the genetic models overall. However, for TLR4 rs4986791, a significant increased PTB risk was found in Africans, and for TLR9 rs352139 a significant increased PTB risk was found in Asians after subgroup analysis by ethnicity, although the enrolled studies were limited.
CONCLUSIONS: There was no association between the polymorphisms in TLR4 and 9 and PTB risk overall, but TLR4 rs4986791 and TLR9 rs352139 might be associated with increased PTB risk in Africans and Asians, respectively. Additional well-designed, larger-scale epidemiological studies are needed to validate our results.

Keywords: Genetic Predisposition to Disease, Genetic Association Studies, Odds Ratio, Polymorphism, Single Nucleotide - genetics, Publication Bias, Risk Factors, Toll-Like Receptor 4 - genetics, Toll-Like Receptor 9 - genetics, Tuberculosis, Pulmonary - genetics