Evaluation of the Immune Response of Individuals Infected with Mycobacterium tuberculosis and Patients with Active Tuberculosis

This study reports the association between Mycobacterium tuberculosis and the immune response to pulmonary tuberculosis (TB). Three groups were analyzed: (a) symptomatic patients with pulmonary tuberculosis (PTB), HIV-negative; (b) healthy individuals, tuberculin skin test reactive (TST+); (c) asymptomatic individuals, TST nonreactive (TST−). Groups B and C presented a negative bacilloscopic smear, normal chest radiographs, and negative HIV. The ELISA was used for IFN-γ, IL-10, TNF-α, and IgG quantification and lymph proliferative assay (LPA) to evaluate the cellular immune response. IgG and LPA increased in all study groups as well as IFN-γ and TNF-α, but IL-10 remained low in all study groups. There was an association between LPA and IFN-γ in group B. It was demonstrated an association between IgG and IL-10 and between IFN-γ and IL-10 in group A. There were direct and significant correlations between LPA and IgG, TNF-α and IFN-γ, IL-10 and IgG, and between IL-10 and IFN-γ, but an inverse relationship was observed between IFN-γ and LPA.