[Significance of elevated serum ACE in pneumology]

Angiotensin-converting enzyme (ACE) levels were measured in the serum of patients with various pulmonary affections (sarcoidosis, tuberculosis, anthracosilicosis, cancer, etc.), with diabetes or renal insufficiency, and in 247 healthy subjects. Mean ACE levels (41.5 U/ml +/- 16) were significantly higher in sarcoidosis than in normal controls (22 U/ml +/- 6), high values (greater than or equal to 34 U/ml) being observed in 62 p. cent of cases. In these patients, the ACE tended to become normal in parallel with clinical and radiological improvement in the disease, and to increase again during relapses. In 75 p. cent of sarcoidosis patients there was concordance between the increase in alveolar lymphocytes and that of serum ACE. Elevated ACE levels were noted in only 3 p. cent of non-sarcoidosis pneumopathies, and in 24 and 18 p. cent of diabetes and renal insufficiency cases respectively. In the absence of these two latter affections, measuring ACE levels is of obvious value for the diagnosis and follow-up surveillance of sarcoidosis.