Angiotensin-converting enzyme in serum and in bronchoalveolar lavage in sarcoidosis

Angiotensin-converting enzyme (ACE) determinations were made in serum and in bronchoalveolar lavage fluid in 20 controls and in 28 patients with sarcoidosis. Serum ACE was significantly higher in patients with active sarcoidosis (54.3 +/- 19.0 SD nmol/ml/ min; n = 24) compared to controls (25.7 +/- 8.2; n = 20) or to patients with inactive sarcoidosis (23.6 +/- 7.3; n = 4). In contrast, ACE in bronchoalveolar lavage fluid was similar in nonsmoking controls (16.4 +/- 7.3 nmol/ml/min/macrophage; n = 8), smoking controls (10.4 +/- 11.9; n = 7); nonsmoking active sarcoidosis patients (16.7 +/- 14.6; n = 10), smoking sarcoidosis patients (17.9 +/- 8.4; n = 6) and inactive sarcoidosis patients (14.5 +/- 8.2; n = 3). Since ACE has been demonstrated by immunofluorescence in mononuclear phagocytes in granulomas, the authors speculate that macrophages recovered by alveolar lavage are not activated and do not reflect sarcoid alveolitis at the tissue level.