Tumor necrosis factor alpha gene polymorphism contributes to pulmonary tuberculosis susceptibility: evidence from a meta-analysis.

This study is to estimate the association between polymorphisms in the tumor necrosis factor alpha (TNF-α) gene and pulmonary tuberculosis susceptibility (pTB). Studies were identified by searching PubMed and ISI web of Knowledge. The strength of association between the TNF-α gene and pTB susceptibility was assessed by odds ratios. Totals of 18 studies including 2, 735 cases and 3, 177 controls were identified referring to four single-nucleotide polymorphisms: -308G>A, -863C>A, -857C>T and -238G>A. The significantly associations were found between -308G>A (Dominant model: OR 0.53, 95% CI 0.35-0.81, P=0.004; Homozygote model: OR 0.51, 95% CI 0.33-0.78, P=0.002), -238G>A (Dominant model: OR 0.33, 95% CI 0.18-0.57, P<0.001) and pTB susceptibility. The results showed that the variant genotype of TNF-α -308G>A was protective in pooled groups of patients with pTB in the dominant genetic model (OR 0.16, 95% CI 0.06-0.39, P<0.001), the homozygote comparison (OR 0.14, 95% CI 0.06-0.36, P<0.001) in African, while that was with -238G>A in the dominant genetic model (OR 0.31, 95% CI 0.18-0.56, P<0.001) in Asian. Our meta-analysis suggest TNF-α -308G>A and -238G>A polymorphisms increases the risk of pTB susceptibility regardless of ethnicity and HIV statue. In Asian population, the significantly association with pTB is TNF-α -238G>A, while TNF-α -308G>A is in African population.