Serum angiotensin converting enzyme (ACE) in silicosis.

Circulating Angiotensin Converting Enzyme (ACE) level, chest X-rays and respiratory function tests were determined in 76 male patients with silicosis. Mean serum ACE in the patients was significantly higher than in 30 healthy controls (129.8 +/- 4 U/ml and 92.4 +/- 22.7 respectively), although individual values were in the normal range in about half of the patients. Enzyme levels were independent of silica dust exposure, X-ray changes, functional lung impairment, age, smoking habits, and presence of chronic obstructive pulmonary disease. However, patients with more severe radiological changes tended to have lower ACE values. Our data confirm that serum ACE level is frequently raised in silicosis, but does not give further information in the evaluation of the disease.