Bronchioalveolar angiotensin converting enzyme activity. Value in assessing disease activity in sarcoidosis.
The disease activity in five patients with sarcoidosis were studied by "conventional" tests over a period of 1 to 3 years. The value of bronchoalveolar lavage (BAL) angiotensin converting enzyme (ACE) activity was examined for its usefulness in predicting disease activity. Gallium scans were positive in 4 of the 5 patients, serum lysozyme in three patients, bronchoalveolar lavage (BAL) lymphocytes were elevated in five patients (three greater than 27%), serum ACE was elevated in one patient and the chest roentgenogram had deteriorated in one patient. Pulmonary function tests were unchanged in all five patients. Patients were ranked in order of activity based on these "conventional" tests. The ranking of activity correlated with the ACE activity in the bronchoalveolar lavage when expressed per micrograms lavage protein. Control subjects had a BAL ACE activity of 7.8 +/- 4.5 units/micrograms protein (p less than 0.05). There was no significant difference in the lavage protein in the control (29 +/- 24 micrograms/ml) compared to the sarcoidosis patients (31 +/- 6 micrograms/ml). We concluded that: (1) the changes in ACE activity in bronchoalveolar lavage represents a real increase in production or decreased clearance of ACE by the lung; (2) BAL ACE is not elevated due to increased permeability of pulmonary capillaries; (3) BAL ACE is a useful measure of disease activity in sarcoidosis patients.