Activation of alveolar macrophages in pulmonary sarcoidosis: lack of correlation with serum angiotensin-converting enzyme activity.

To identify the activation of alveolar macrophages as a direct measure of disease activity in pulmonary sarcoidosis and to evaluate the possible relationship with serum angiotensin-converting enzyme (ACE) levels, we studied the morphology and function of alveolar macrophages obtained by bronchoalveolar lavage from patients with active disease (n = 12) and inactive disease (n = 5), and from normal controls (n = 11). At the time of lavage, 6 of 12 patients with active disease showed an elevation of serum ACE levels. When alveolar macrophages were cultured, more cells from active disease adhered to glass, spread out, and were positive for NBT reduction (p less than 0.001). Lysosomal enzyme (beta-galactosidase) activity was higher only in patients with active disease (p less than 0.001). In active disease, there were no significant differences in morphology or function of alveolar macrophages between higher and normal serum ACE levels. Thus, alveolar macrophages were activated in active pulmonary sarcoidosis and no correlation was found with serum ACE levels. These results suggest that serum ACE levels do not accurately reflect the activity of disease in the lung.