Tissue angiotensin-converting enzyme and lysosomal enzyme levels in skin diseases.

The activities of tissue angiotensin-converting enzyme (ACE) were investigated in several skin diseases. Biopsy specimens were taken from 49 patients with granulomatous lesions, including sarcoidosis, 16 patients with nongranulomatous lesions, and 13 normal individuals. The ACE level was measured fluorometrically and the lysosomal enzyme levels were measured by established techniques. It was found that ACE activity increased in all granulomatous skin lesions, but not in other inflammatory lesions. The enzyme activity showed an increase that paralleled the time course of the disease. In contrast, lysosomal enzymes increased in various types of skin lesions, suggesting that they reflect nonspecific inflammation. These findings indicate that the tissue ACE level may be a marker for granulomatous inflammation, but one that is not specific for sarcoidosis.