Interferon-Gamma Improves Macrophages Function against M. tuberculosis in Multidrug-Resistant Tuberculosis Patients

Background . Mycobacterium tuberculosis ( M. tuberculosis ) that causes tuberculosis (TB) kills millions of infected people annually especially multidrug-resistant tuberculosis (MDR-TB). On infection, macrophages recognize the mycobacteria by toll-like receptor (TLR) followed by phagocytosis and control of mycobacteria. In addition, macrophages also secrete IL-12 to induce IFN- γ production by T, which, in turn, increases the phagocytosis and oxidative burst. Individuals with defects in innate or adaptive immunity exhibit increased susceptibility to M. tuberculosis . Understanding these immunologic mechanisms will help in TB control. We aimed to investigate the immunopathologic mechanisms in MDR-TB and role of recombinant human interferon-gamma (rhIFN- γ ). Study Design and Methods . Monocyte-derived macrophages (MDMs) were generated from peripheral blood mononuclear cells of MDR-TB patients and healthy subjects and were investigated for immunologic response by ELISA and flow cytometry. Results . Different functional and molecular anomalies were observed in macrophages. In addition, a defective immune response to M. tuberculosis from the patient's MDMs was characterized, which in turn improved by pretreatment with rhIFN- γ . Conclusion . This work highlights the fact that rhIFN- γ improves macrophages function against M. tuberculosis and treatment of patients with poor responsiveness to TB therapy may be needed in future to include IFN- γ as adjuvant therapy after the full characterization of pathological and molecular mechanisms in these and in other more multidrug-resistant TB patients.