IL-18 genetic polymorphisms may contribute to the pathogenesis of tuberculosis among Asians: a meta-analysis of case-control studies.

This current meta-analysis of case-control studies was continued to investigate whether the genetic polymorphisms of IL-18 gene contribute to the occurrence and progression of tuberculosis (TB). We searched certain English and Chinese databases for relevant studies without language restrictions. Meta-analysis for the moment was performed with the adoption of the STATA statistical software. Crude OR and its corresponding 95 % confidence interval (95 % CI) were calculated as estimates of relative risk for UC under different genetic models. Seven case-control studies (TB patients = 1,325, healthy subjects = 1,778) were included for the following analysis. We evaluated two functional polymorphisms (rs1946518 C>A and rs187238 G>C). Pooled OR within the progression of statistical analysis indicated that the specific polymorphism of IL-18 rs1946518 C>A showed a closely relationship with the elevated susceptibility to TB under those three genetic models (allele model: OR 1.24, 95 % CI 1.11-1.38, P < 0.001; dominant model: OR 1.41, 95 % CI 1.21-1.65, P < 0.001; homozygous model: OR 1.46, 95 % CI 1.15-1.86, P = 0.002; respectively). However, we observed no statistical associations of the IL-18 rs187238 G>C polymorphism with the susceptibility to TB under any of the genetic models (all P > 0.05). Country-stratified analysis results detected that the variants of IL-18 may be strongly enrolled in the risk of TB among populations in China (allele model: OR 1.19, 95 % CI 1.06-1.33, P = 0.003; recessive model: OR 1.54, 95 % CI 1.00-2.36, P = 0.048; homozygous model: OR 1.59, 95 % CI 1.09-2.33, P = 0.016; respectively), but not among populations in Iran, Korea and India (all P > 0.05). Current results provide strong evidence that IL-18 mutations may be evidently related to the occurrence and development of TB, especially for the rs1946518 C>A polymorphism among populations in China.