Serum angiotensin-converting enzyme and delayed hypersensitivity in pulmonary tuberculosis.

In contrast to sarcoidosis, there was no difference between serum angiotensin-converting enzyme (ACE) levels in a group of 100 adult Indonesian patients with active pulmonary tuberculosis and in 108 matched healthy control subjects. There was a significant inverse correlation between the diameter of the cutaneous reaction to tuberculin and serum ACE levels. It is postulated that, as both delayed hypersensitivity and ACE synthesis within granulomas appear to be the result of T-cell induced secretory activities of macrophages, this inverse relationship results from competition for receptor sites for the relevant signal molecules on the macrophage surface.