BACKGROUNDGenetic 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.

METHODSA 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 (ORs) and 95% confidence intervals (95% CIs) were calculated using either the fixed-effects model or the random-effects model for different genetic models based on the heterogeneity examination.

RESULTSA 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.

CONCLUSIONSOur 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.