Cellular responses to MPT-51, GlcB and ESAT-6 among MDR-TB and active tuberculosis patients in Brazil

Summary Multi-drug resistant pulmonary tuberculosis (MDR-TB) may result from either insufficiency of the host cellular immune response or mycobacterial mechanisms of resistance. Mycobacterium tuberculosis -specific CD8+ and CD4+ T lymphocytes from MDR-TB patients are poorly studied. The aim of this study was to evaluate CD4+ IFN-γ+ , CD4+ IL-10+ , CD8+ IFN-γ+ and CD8+ IL-10+ cell populations by flow cytometry in non-resistant TB and multi-drug resistant tuberculosis (MDR-TB) patients from mid-central Brazil after stimulation with MPT-51, GlcB and ESAT-6 recombinant antigens from M. tuberculosis in comparison to tuberculin skin test negative (TST) healthy individuals. Non-resistant TB patients present specific cellular responses (CD4 and CD8, both IFN-γ and IL-10) to GlcB, MPT-51 and ESAT-6; while MDR-TB patients present only CD8+ IFN-γ+ responses to ESAT-6 and CD8+ IL-10+ responses to GlcB and ESAT-6. The results show that MDR-TB patients present impaired specific CD4 IFN-γ and IL-10 responses and increased/normal specific CD8 IFN-γ and IL-10 responses. This suggests an important role for CD8 function in these patients.