Association between interferon gamma receptor 1 -56C/T gene polymorphism and tuberculosis susceptibility: a meta-analysis

Background Genetic variations in the interferon-gamma (IFN-γ) receptor 1 gene ( IFNGR1 ) may contribute to tuberculosis (TB) risk in different populations. Many studies have investigated the relationship between IFNGR1 56C/T polymorphism and the susceptibility to TB, but have yielded conflicting results. A comprehensive meta-analysis is needed to provide a more accurate estimation of the relationship between them. Methods A literature search based on a combination of manual and computer-based methods was conducted on four English databases (PubMed, Science Direct, SpringerLink, and EBSCO) and three Chinese databases (Wanfang, CQVIP, and Chinese National Knowledge Infrastructure databases). Pooled odds ratios ( OR s) and 95% confidence intervals (95% CI s) were calculated using either the fixed-effects model or the random-effects model for different genetic models based on the heterogeneity examination. Results A total of six studies comprising 1 497 confirmed TB cases and 1 802 controls were included in this meta-analysis. Overall, no significant association was observed between IFNGR1 -56C/T polymorphism and TB susceptibility (C vs. T, OR =0.90, 95% CI 0.69–1.17; CC vs. TT, OR =0.87, 95% CI 0.65–1.18; TC vs. TT, OR =1.031, 95% CI 0.872–1.219; CC+TC vs. TT, OR =0.89, 95% CI 0.64–1.26; CC vs. TC+TT, OR =0.92, 95% CI 0.66–1.29). In subgroup analysis, a significant association was found in the dominant model (CC+TC vs. TT, OR =1.24, 95% CI 1.02–1.51) in Africans, but not in Asians or Caucasians. Conclusions Our meta-analysis did not provide enough powerful evidence to identify a significant association between IFNGR1 -56C/T polymorphism and TB susceptibility in the overall population. In subgroup analysis, it indicates that IFNGR1 -56C/T is possibly associated with increased TB risk in Africans, but not in Asians or Caucasians. However, larger sample size and better-designed case-control studies are needed to validate these findings.