Normal serum angiotensin converting enzyme activity in patients with newly diagnosed sarcoidosis.

Twenty-four patients with sarcoidosis had normal serum angiotensin converting enzyme (SACE) values at time of diagnosis. Sixteen patients were in stage I and eight of these underwent complete remission and four followed a stable course. Seven of eight patients in stages II and III experienced improvement while receiving glucocorticoid treatment. In six, serial SACE measurements fell significantly, paralleling the clinical improvement. The data suggest that a normal SACE in stage I indicates a good prognosis. Patients in stages II and III with normal SACE levels may still have active disease potentially responsive to glucocorticoid treatment. The reduction of SACE while receiving treatment may be viewed as the "suppressible" SACE compartment, representing that portion of the enzyme elaborated by the granuloma or its cellular precursors. The level remaining after suppression by glucocorticoids may be considered "basal" SACE, probably related to normal turnover of SACE producing cells in vascular endothelium.