The effect of P2X7 receptor 1513 polymorphism on susceptibility to tuberculosis: A meta-analysis

Studies of the association between the purinergic receptor P2X, ligand-gated ion channel 7 (P2X7 receptor) gene 1513A/C polymorphism and susceptibility to tuberculosis have yielded inconsistent results. We performed this meta-analysis to help clarify these inconsistencies. After systematically searching PUBMED, MEDLINE, EMBASE and ISI Web of knowledge, two of the authors independently extracted relevant data and a meta-analysis was performed by using STATA11.0 software. A total number of nine studies involving 2195 cases and 2036 controls were identified. The results indicated that P2X7 receptor gene 1513C allele (OR 1.389, 95% CI 1.161-1.660, p<0.001) and CC genotype (1.582, 95% CI 1.129-2.217, p=0. 012) were significantly associated with increased susceptibility to tuberculosis. Subgroup analysis indicated that this SNP greatly contributed to susceptibility to tuberculosis in Asians. The C allele of P2X7 receptor gene 1513A/C polymorphism was also associated with increased susceptibility to pulmonary tuberculosis in Asians (C vs. A: OR 1.420, 95% CI 1.163-1.733, p=0.001; (CC+AC) vs. AA: OR 1.522, 95% CI 1.186-1.953, p=0.001). Greater association between P2X7 receptor gene 1513A/C polymorphism and susceptibility to extra-pulmonary tuberculosis with bigger ORs were found (C vs. A, OR 2.035, 95% CI 1.236-3.352, p=0.005; CC vs. AA, OR 3.788, 95% CI 1.434-10.009, p=0.007; AC vs. AA, OR 2.148, 95% CI 1.252-3.684, p=0.005; (CC+AC) vs. AA, OR 2.386, 95% CI 1.302-4.374, p=0.005; CC vs. (AC+AA), OR 2.692, 95% CI 1.242-5.836, p=0. 012). This meta-analysis indicates that the C allele of P2X7 receptor gene 1513A/C polymorphism is a risk factor for pulmonary tuberculosis in Asians, while not in Africans or Latinos and a risk for extra-pulmonary tuberculosis. Further well-designed, large scale studies are required to confirm this conclusion.