The Relationship between Tumor Necrosis Factor-α Polymorphisms and Hepatitis C Virus Infection: A Systematic Review and Meta-Analysis

Background and aims: Hepatitis C virus (HCV) is now recognized as one of the major causes of chronic liver disease. It is also one of the most common complications in maintenance hemodialysis (HD) patients. Tumor necrosis factor (TNF)-alpha promoter polymorphisms are observed to modulate TNF-alpha levels and thought to have an effect on susceptibility to HCV infection and the virus clearance, but the results are inconsistent. In this study, a systematic review and meta-analysis of the published data was performed to evaluate the relationship between the TNF-alpha-238, -308 polymorphisms and HCV infection. Methods: A total of 15 studies published were analyzed, which were indexed from PubMed, Embase, and CNKI databases (up to December 2010). All the data were analyzed using RevMan 4.2 software. Odds ratios (OR) and confidence intervals (95% CI) were calculated by fixed or random-effects models. Heterogeneity and publication bias across the studies were also explored. Results: The data showed no significant association between TNF-alpha-308, -238 gene polymorphisms and the susceptibility to HCV infection in the global group (p = 0.28, p = 0.38, respectively) and the sub-groups (European, American, African, and Asian). Besides, the distributions of TNF-alpha-308, -238 A/G alleles were also not significantly different between the persistent infection group and the spontaneous clearance group (p = 0.64, p = 0.75, respectively). Conclusion: TNF-alpha-238, -308 gene polymorphisms might have no effect on susceptibility to HCV infection and the virus clearance. The findings of this meta-analysis have implications in the optimal prevention of HCV in HD patients and in the guidance of future research.