The role of Mycobacterium tuberculosis complex species on apoptosis and necroptosis state of macrophages derived from active pulmonary tuberculosis patients.

OBJECTIVE The role of Mycobacterium tuberculosis complex (MTBC) species in tuberculosis (TB) infection in human is still questioned. The aim of this study was to determine whether M. tuberculosis and M. bovis is associated with apoptosis and necroptosis by measuring the expression of specific signaling pathways components (Fas-associated protein with death domain (FADD) and receptor interacting protein 3 (RIP3)), and the level of apoptosis. RESULTS We recruited 30 patients with pulmonary TB; 24 patients were infected with M. tuberculosis Beijing strain and six patients with M. bovis BCG strain. M. tuberculosis-infected patients were more likely to have severe lung damage compared to those infected with M. bovis (odds ratio [OR] 7.60; 95% confidence interval [CI] 1.07-54.09). M. tuberculosis infection was associated with lower expression of FADD and lower apoptosis level of macrophages compared to M. bovis. No significant different of RIP3 between MTBC species groups. In conclusion, M. tuberculosis Beijing strain was associated with severe pulmonary damage, inhibited FADD expression and reduced apoptosis level of macrophages derived from pulmonary TB patients. This suggests that the M. tuberculosis Beijing strain is potentially to be used as determinant of disease progressivity and tissue damage in TB cases.