Increased levels of circulating interleukin-18 in patients with advanced turberculosis

Interleukin-18 (IL-18) has recently been identified as an interferon-gamma- inducing factor and it plays an important role in the Th1 response. We meas ured serum levels of IL-18 and interferon-gamma (IFN-gamma) in 43 patients with pulmonary tuberculosis and 25 healthy control subjects. Significantly increased levels of circulating IL-18 and IFN-gamma were found in pulmonary tuberculosis as compared with those in healthy control subjects. Circulati ng IL-18 and IFN-gamma correlated with the extent of disease in pulmonary t uberculosis. We found significantly increased levels of circulating IL-18 a nd IFN-gamma in the patients with high-grade fever. Circulating IL-18 signi ficantly correlated with circulating IFN-gamma. IL-18 may play an important role in immune response to human infection with Mycobacterium tuberculosis .