P2X7 Gene Polymorphisms and Risk Assessment for Pulmonary Tuberculosis in Asian Indians

OBJECTIVE Pulmonary tuberculosis (PTB) is a leading cause of morbidity and mortality. Macrophages play an important role in the immunopathogenesis of tuberculosis. Extracellular ATP induces macrophage bactericidal activity through activation of the purinergic P2X7 receptor. This case- control study assesses the association of -762 T/C, 1513A/C and 1729T/A P2X7 polymorphisms in patients with PTB and healthy controls to establish association if any with risk of developing the disease. MATERIALS AND METHODS The genotyping for P2X7 was carried out using PCR and RFLP analysis in 256 individuals, which included 156 active PTB patients and 100 age and sex, matched healthy volunteers with no clinical symptoms or family history of PTB as controls. RESULTS A chi square test showed a significant difference between the PTB patient and controls for -762 C allele; p=0.0051 (OR 1.6972, CI 95% 1.1839 to 2.4332) and 1729 T allele was found to be positively associated with the PTB; p < 0.0005 (OR- 2.4623, CI 95% 1.6376 to 3.7022). 1513A/C polymorphism did not show any significant difference between the two groups. SIGNIFICANCE The study revealed a significant association of P2X7-762C allele and P2X7 1729T allele receptor polymorphisms with PTB in Asian Indian population. The use of these alleles as biomarkers for identifying individuals at high risk of developing TB needs to be ascertained.