Activated alveolar macrophages in subclinical pulmonary inflammation in collagen vascular diseases.

A study was initiated to determine whether alveolar macrophages from patients with collagen vascular diseases but free of pulmonary symptoms were spontaneously activated and whether they released various mediators related to the pathogenesis of pulmonary fibrosis. Alveolar macrophages obtained by bronchoalveolar lavage from 32 patients with proved collagen vascular disease but no evidence of lung disease were compared with those from 10 patients with collagen vascular disease with interstitial lung disease (CVD-ILD) and from 10 healthy controls. The total number of alveolar macrophages did not differ between patients with collagen vascular disease and controls but were substantially increased in the CVD-ILD group. Alveolar macrophages from 31 of the 32 patients with collagen vascular disease and from all 10 in the CVD-ILD group had at least one criterion of activation. Neutrophil chemotactic activity was detected in supernatants from alveolar macrophage culture in 23 of the 32 patients with collagen vascular disease and from nine of the 10 in the CVD-ILD group; fibronectin secretion by alveolar macrophages was increased in 12 of the 32 patients with collagen vascular disease and in nine of the 10 in the CVD-ILD group. Furthermore, alveolar macrophages from 20 of the 32 patients with collagen vascular disease and four of the 10 CVD-ILD patients spontaneously released increased amounts of superoxide anion. Thus alveolar macrophages were spontaneously activated in a high proportion of patients with collagen vascular disease.