The value of serum interferon-gamma level in the differential diagnosis of active and inactive pulmonary tuberculosis.

Interferon (IFN)-gamma plays a pivotal role in protective immunity against Mycobacterium tuberculosis. Elevations of IFN-gamma have been found in the affected lung and bloodstream of patients with pulmonary tuberculosis. In the present study, we aimed to investigate the role of serum IFN-gamma level in the differential diagnosis of active and inactive pulmonary tuberculosis. Fourty seven patients with newly diagnosed active pulmonary tuberculosis, 21 patients with inactive pulmonary tuberculosis, and 20 healthy volunteers were enrolled in the study. Serum samples were collected from each subject and stored at - 70 degrees C until the analysis of IFN-gamma. The mean value of IFN-gamma levels were 9.3 +/- 4.6 pg/mL in patients with newly diagnosed pulmonary tuberculosis, 9.8 +/- 3.8 pg/mL in patients with inactive tuberculosis, and 10.2 +/- 3.4 pg/mL in healthy controls. The comparison of IFN-gamma levels of the three groups was not found statistically significant (p= 0.4). Serum IFN-gamma level was not found to be valuable in the differential diagnosis of active and inactive pulmonary tuberculosis.