Direct radioimmunoassay of angiotensin-converting enzyme in serum and bronchoalveolar lavage fluid from patients with pulmonary diseases
Inoue, Y.
Nihon Kyobu Shikkan Gakkai Zasshi 26(2): 129-138
1988
ISSN/ISBN: 0301-1542 PMID: 2841524 Document Number: 308244
The concentration of angiotensin-converting enzyme (ACE) was measured in sera fom 104 subjects and in bronchoalveolar lavage fluid (BALF) from 62 subjects by direct radioimmunoassay (RIA) using antiserum to human kidney ACE. Serum ACE concentration in normal controls was 335.2 .+-. 109.1 ng/ml (mean .+-. SD). The serum ACE concentration was significantly higher in patients with sarcoidosis (658.0 .+-. 239.0 ng/ml, p < 0.01) and silicosis (509.5 .+-. 186.1 ng/ml, p < 0.01) than that in normal controls. In patients with asbestosis, lung cancer, pulmonary tuberculosis and pulmonary emphysema, specific activities of serum ACE were significantly lower than in normal controls. The concentration of ACE in BALF was calculated from urea dilution of BALF (epithelial lining fluid; ELF). ACE concentration in BALF from normal controls was 293.4 .+-. 124.9 ng/min, which was similar to serum ACE concentration. The ACE concentrations in BALF from patients with sarcoidosis (771.5 .+-. 450.8 ng/ml, p < 0.01) and silicosis (487.1 .+-. 264.6 ng/ml, p < 0.05) were significantly higher than in normal controls. The concentration of BALF ACE per pulmonary alveolar macrophage (PAM), corrected with the number of PAMs, was significantly elevated only in patients with sarcoidosis. In the immunofluorescence study, intense fluorescence was shown only in PAMs from patients with sarcoidosis and weak fluorescence with silicosis. The number of PAMs in BALF from patients with silicosis was significantly more than that in normal controls. Data show that the increase in ACE in BALF from patients with sarcoidosis and silicosis may be caused by augmentation of ACE production by PAM in patients with sercoidosis, and by multiplication of ACE-producing PAM in patients with silicosis.