Association Between TNF-α-308G/A Polymorphism and Risk of Immune Thrombocytopenia: A Meta-Analysis

Objective: Previous studies have investigated the association between tumor necrosis factor-alpha (TNF-alpha) -308G/A polymorphism and risk of immune thrombocytopenia (ITP), but the reported results have been inconsistent. Thus, a systematic meta-analysis was performed to resolve this discrepancy. Methods: Electronic databases and the cited references of the obtained published articles were manually searched. Quality assessment of each study was conducted using the Newcastle-Ottawa Scale (NOS). All case-control studies were used to assess the strength of the association. Statistical analysis was performed using Stata version 12.0. Results: Eight high-quality studies, including 947 patients and 1911 controls, were selected for the final meta-analysis. There was no significant association between TNF-alpha -308G/A polymorphism and ITP in overall and Asian populations. However, a significant positive association was observed between them in the dominant genetic model (AA+AG versus GG) in the Caucasian population (OR = 1.35, 95% confidence interval [CI]: 1.07-1.71, P-H = 0.173). Conclusions: Our finding suggested that TNF-alpha -308G/A might be involved in development of ITP in the Caucasian population, but not in the Asian population. Among Caucasians the A allele (AA+AG) was associated with ITP. However, larger-scale studies are required to confirm our findings.