Genetic association between TNF-α −857 C/T polymorphism and ankylosing spondylitis susceptibility: evidence from a meta-analysis

Certain studies have suggested that the tumor necrosis factor-α (TNF-α) -857 C/T polymorphism is associated with risk of ankylosing spondylitis. However, the conclusions remain controversial. Therefore, we performed a meta-analysis to provide a more precise conclusion. Such databases as PubMed, Embase, CBM, CNKI, and Wanfang Data were searched to identify relevant studies up to August 26, 2015. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association between TNF-α -857 C/T polymorphism and ankylosing spondylitis susceptibility. A total of 10 studies were included in the meta-analysis. Overall, an elevated risk between TNF-α -857 C/T polymorphism and ankylosing spondylitis was observed in three genetic model (T vs. C: OR 1.86, 95% CI 1.19-2.92; CT vs. CC: OR 2.51, 95% CI 1.49-4.23; TT + CT vs. CC: OR 2.46, 95% CI 1.40-4.30), except in homozygote model (TT vs. CC: OR 2.41, 95% CI 0.96-6.06) and recessive model (TT vs. CT + CC: OR 1.54, 95% CI 0.71-3.35). Sensitivity analysis showed the overall results were robust. Subgroup analyses according to Hardy-Weinberg equilibrium and ethnicity showed that the increased risk of ankylosing spondylitis were predominant in Asian population. This meta-analysis indicated that TNF-α -857 C/T polymorphism might increase the susceptibility of ankylosing spondylitis, especially in Asians. Further studies were needed to verify the conclusion.