[Practical value of the assay of serum angiotensin converting enzyme activity in sarcoidosis].

Serum levels of angiotensin conversion enzyme (A.C.E.) are increased in 60 to 80% of cases of sarcoidosis. A.C.E. levels were measured as part of the initial assessment of 70 patients with the disease, with repeated measurements in 18 of them. The subsequent course of sarcoidosis was evaluated over a minimum period of 7 months, in relation to initial serum A.C.E. levels. A high serum A.C.E. level is indicative of the secretion of the cells of the epithelioid and giant cell granuloma and reflects the activity of the disease at the particular time without providing any definite prognostic information. Study of 6 patients treated with corticosteroids showed that serum A.C.E. levels rose again when treatment was reduced or stopped in 4 of them, this renewed rise appearing to precede the radiological recurrence. Whilst the prognostic value of alveolar lymphocytosis is greater than that of serum A.C.E. levels in sarcoidosis, measurement of serum A.C.E. is easier in the context of therapeutic surveillance.