Interferon gamma assay for diagnosis of childhood tuberculosis

We measured interferon-gamma (IFN-gamma) in supernatant of peripheral blood mononuclear cell (PBMC) cultures stimulated with mycobacterial antigens. The study included ten children with newly diagnosed active pulmonary tuberculosis (TB), ten with inactive TB and 8 healthy controls. IFN-gamma was quantified by ELISA. Antigen stimulated PBMCs produced IFN-gamma at significantly higher levels than the background levels of nonstimulated cultures. Following specific antigen stimulation in vitro with TB bacilli, the PBMCs from patients with active and inactive TB produced significantly higher levels of IFN-gamma (433.15+/-119.80 and 420.64+/-131.52 respectively) than controls (241.2+/-119.74), (P< 0.001). However, no significant difference was found between active and inactive TB patients. In conclusion, estimation of specific IFN-gamma production by PBMC may be a useful immunological tool for diagnosis of childhood tuberculosis.