Pulmonary Tuberculosis: Evaluation of Interferon-γ Levels as an Immunological Healing Marker Based on the Response to the Bacillus Calmette-Guerin

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis whose interaction with the host may lead to a cell-mediated protective immune response. The presence of interferon-γ (IFN-γ) is related to this response. With the purpose of understanding the immunological mechanisms involved in this protection, the lymphoproliferative response, IFN-γ and other cytokines like interleukin (IL-5, IL-10), and tumor necrosis factor alpha (TNF-α) were evaluated before and after the use of anti-TB drugs on 30 patients with active TB disease, 24 healthy household contacts of active TB patients, with positive purified protein derivative (PPD) skin tests (induration ≥ 10 mm), and 34 asymptomatic individuals with negative PPD skin test results (induration ≤ 5 mm). The positive lymphoproliferative response among peripheral blood mononuclear cells of patients showed high levels of IFN-γ, TNF-α, and IL-10. No significant levels of IL-5 were detected. After treatment with rifampicina, isoniazida, and pirazinamida, only the levels of IFN-γ increased significantly (p < 0.01). These results highlight the need for further evaluation of IFN-γ production as a healing prognostic of patients treated