Lack of association between Toll-like receptor 4 gene Asp299Gly and Thr399Ile polymorphisms and tuberculosis susceptibility: a meta-analysis

Objective: Toll-like receptor 4 (TLR4) plays a vital role in immunity to tubercle bacillus and its gene polymorphisms are supposed to affect tuberculosis susceptibility in some rather than all studies. Then, we integrated published data and performed a comprehensive meta-analysis to get more reliable estimations for the strength of associations between TLR4 gene polymorphisms and the risk of tuberculosis.

Methods: We systematically searched the electronic PubMed database for research articles about TLR4 gene polymorphisms and tuberculosis up to February 2012. Revman 5.0 software was adopted to conduct the meta-analysis. Crude odds ratio (ORs) and 95% confidence intervals (95% CIs) were calculated by either fixed-effects model or random-effects model.

Results: Finally, six case-control studies were identified, involving 1587 controls and 2110 patients. Overall, no significant associations were found between TLR4 gene Asp299Gly polymorphism and tuberculosis in the codominant models (GG vs AA: OR=1.56, 95% CI=0.76-3.21, P=0.23; GA vs AA: OR=1.01, 95% CI=0.84-1.23, P=0.89), the dominant model (GG+GA vs AA: OR=1.04, 95% CI=0.80-1.35, P=0.75), the recessive model (GG vs GA+AA: OR=1.55, 95% CI=0.75-3.19, P=0.24) and the allele model (G vs A: OR=1.06, 95% CI=0.81-1.40, P=0.66). Similarly, no significant associations between TLR4 gene Thr399Ile and tuberculosis were observed (all P>0.05).

Conclusions: The present meta-analysis suggests that TLR4 gene Asp299Gly and Thr399Ile polymorphisms are not associated with the susceptibility of tuberculosis.