Soluble interleukin-2 receptors in pulmonary tuberculosis

Serum levels of soluble interleukin-2 receptor (IL-2R) were measured in patients with pulmonary tuberculosis, nontuberculous pulmonary diseases (bacterial pneumonia, lower respiratory tract infection, lung cancer), and in normal volunteers. Patients with tuberculosis had increased levels of soluble IL-2R compared to normal controls. Abnormally elevated levels were also shown in patients with nontuberculous pulmonary diseases, suggesting that elevations of soluble IL-2R are not specific for tuberculosis. In patients with tuberculosis, elevated levels of soluble IL-2R were steadily decreased to normal levels during successful treatment. Additionally, soluble IL-2R levels in tuberculosis were closely correlated with adenosine deaminase levels. Thus, it seems possible that measurements of soluble IL-2R may be beneficial in the diagnosis and the management of patients with tuberculosis. Furthermore, we demonstrated that elevated levels of soluble IL-2R in tuberculosis appear to be a consequence of cellular activation of mononuclear cells and not to be the result of cell death with subsequent IL-2R release.