Plasma angiotensin converting enzyme in the diagnosis and monitoring of disease activity in sarcoidosis.

The value of plasma angiotensin converting enzyme (plasma-ACE) as an indicator of activity in sarcoidosis was evaluated using strictly defined clinical, radiological, functional and pathologic criteria. The cross-sectional study involved 75 untreated patients. Fifty-four with active sarcoidosis had a significantly higher plasma-ACE (68.5 +/- 22.6 U/ml) than 8 with possibly active disease (44.6 +/- 9.5 U/ml; p less than 0.001), 13 with inactive disease (41.8 +/- 13.3 U/ml; p less than 0.001) and 69 healthy controls (35.9 +/- 9.4 U/ml; p less than 0.001). Within the active disease group, no significant differences in plasma-ACE were found, when subdivided by chest X-ray stage or by possible, subsequent, corticosteroid therapy. The longitudinal study was made on 36 patients with active sarcoidosis. In 70% of the additional examinations, the clinical evolution was correlated with the changes in plasma-ACE. This relationship showed no significant difference (p greater than 0.1) between the 17 patients who remained untreated and the 19 patients who received steroids. This study emphasizes that plasma-ACE is a very useful indicator of the activity of sarcoidosis and is valuable in monitoring the evolution of the disease whether spontaneous or corticosteroid-induced.