IL-18 polymorphisms (-137C/G and -607A/C) are not associated with tuberculosis

Many studies have demonstrated that (IL-18) polymorphisms (including -137C/G and -607A/C) are correlated with the risk of tuberculosis. However, the meaning of this finding remains a matter of debate. In this study, electronic databases, including PubMed, EMBASE, Web of Science, Google Scholar and CNKI, were systemically queried to identify relevant studies. Subsequently, odds ratios and corresponding 95% confidence intervals were analysed. Our data indicated that the IL-18 -137C/G polymorphism was not related to tuberculosis susceptibility (GG vs. AA odds ratio = 0.71, 95% confidence interval 0.43–1.17; GA vs. AA: odds ratio =0.80, 95% confidence interval 0.57–1.13; dominant model: odds ratio = 0.78, 95% confidence interval 0.56–1.08; recessive model: odds ratio = 0.76, 95% confidence interval 0.46–1.25). Similarly, there was no association between the IL-18 -607A/C polymorphism and tuberculosis susceptibility (AA vs. CC: odds ratio = 1.25, 95% confidence interval 0.87–1.79; CA vs. CC: odds ratio = 1.10, 95% confidence interval 0.93–1.29; dominant model: odds ratio = 1.13, 95% confidence interval 0.90–1.41; recessive model: odds ratios=1.17, 95% confidence interval 0.90–1.53). No association was found in the subgroup analysis based on the Hardy–Weinberg equilibrium. In addition, there was no publication bias. The two IL-18 gene polymorphisms (-137C/G and -607A/C) were not markedly correlated with tuberculosis susceptibility. Well-designed studies with more subjects will be required for further validation of these results.