[Diagnostic value of serum angiotensin converting enzyme activity in sarcoidosis (author's transl)]

Serum angiotensin converting enzyme activity was measured in 60 blood donors and 100 patients with sarcoidosis histologically confirmed using a spectrophotometric assay with hippurylhistidylleucine as substrate. Sex related differences in the enzyme activity could not be observed. ACE was found to be markedly raised above the normal range (the mean of the control subjects plus 2 standard deviations) in 53 (58.2%) out of 91 untreated patients. The distribution of the enzyme activities was significantly different as compared to the control group. Nine patients with sarcoidosis receiving steroids had a mean level within the normal range. ACE level in stage II group tended to be more elevated compared to stage I, but this difference was not significant. Extrapulmonary sarcoidosis (with and without pulmonary involvement) appeared to be associated with especially high ACE activities. The distribution of the enzyme activities within the groups of untreated patients failed to reveal statistically significant differences. Therefore it was not possible to determine the clinical state of the disease and to discriminate between the stages (I and II) of sarcoidosis by the measurement of serum ACE level. However as the results suggest serum ACE assays can be a useful aid in diagnosis of sarcoidosis. Further investigations may demonstrate the value of this in vitro method for the clinical management of the disease including prognosis and therapeutic effects.