Angiotensin-converting enzyme in bronchoalveolar lavage fluid in sarcoidosis

This is the first Australian study of angiotensin converting enzyme (ACE) in bronchoalveolar lavage fluid in 51 patients with sarcoidosis. The aim was: 1) to establish the range of lavage ACE in healthy smokers and non-smoking patients with sarcoidosis. 2) to evaluate the clinical usefulness of lavage ACE. Seventeen control subjects and 51 sarcoid patients all underwent bronchoalveolar lavage, the latter also having 67Gallium scan, spirometry and carbon monoxide uptake. Eighteen patients had all tests repeated six months later. Lavage ACE was significantly higher in sarcoid non-smokers than control non-smokers (p < 0.05). In the 51 sarcoid patients, lavage ACE/albumin ratios were 10-fold higher than serum ACE/albumin ratios (p < 0.0001). In sarcoid patients with raised intrathoracic 67Gallium uptake, lavage ACE was significantly higher than those patients with normal uptake (p < 0.05). Expressing lavage ACE as ACE/albumin ratios reduced the statistical significance of correlations with other parameters, eg, lavage % lymphocytes, and lavage IgG. Lavage ACE levels changed concordantly with lung function 67Gallium scan and lavage lymphocytes, albumin and IgG. However, the wide distribution of lavage ACE in control and sarcoid subjects and the influence of smoking history severely limits its clinical application.