Comparison of interferon-gamma response between tuberculosis and non-tubercular pneumonia

Objective and design: Macrophages aided by interferon-gamma (IFN-gamma) are vital to controlling Mycobacterium tuberculosis (M. tuberculosis) infection. Although numerous studies have compared IFN-gamma response between tubercular patients and healthy controls, no studies have investigated IFN-gamma response in patients with pulmonary tuberculosis and non-tubercular pneumonia. The aim of this work was to examine the difference in IFN-gamma response between patients with tuberculosis and non-tubercular pneumonia. Methods: IFN-gamma production was detected based on the difference in supernatants between non-stimulated and stimulated peripheral blood mononuclear cells by phytohernagglutinin in 83 tubercular patients and 47 patients with pneumonia. Presence of a cavity on chest radiography and co-morbidities of pneurnoconiosis, bronchiectasis, liver cirrhosis, renal failure on hemodialysis, diabetes mellitus (DM) and lung cancer were recorded for analysis. Results: Interferon-gamma response, DM and a cavity on chest radiography were independent factors for predicting active pulmonary tuberculosis. Interferon-gamma response was decreased in patients with pulmonary tuberculosis compared with that in patients with non-tubercular pneumonia. Notably, M. tuberculosis infection was the principal factor correlated with IFN-gamma response. Conclusion: The IFN-gamma response was principally affected by M. tuberculosis infection and not by other co-morbidities. Further study is required to identify the mechanism of decreased IFN-gamma production