Value of measuring serum angiotensin I converting enzyme and serum lysozyme in the management of sarcoidosis.

Serum angiotensin I converting enzyme (ACE) and lysozyme have been measured in 23 controls, 115 patients with sarcoidosis, and 64 with other chest diseases. Both enzymes were significantly raised in sarcoidosis. ACE was raised above the normal range in 21 of 72 (29%) patients with definite sarcoidosis and in 17 of 38 (45%) of those who were untreated and seen within one year of presentation. The rise discriminated usefully between those with stable and progressive disease (5% and 62% respectively). Lysozyme was raised in 50 of 72 (69%) patients with sarcoidosis but also in 11 of 54 (20%) patients with other chest diseases. Discrimination between stable and progressive disease was useful only if very high levels were considered. Five patients had serial measurements after treatment with oral steroids and showed a progressive fall in levals of both enzymes, but patients with other diseases also showed a significant fall within the normal range when so treated. Measurement of these enzymes may help in the management of some cases of sarcoidosis, but results require critical interpretation.