[Fibrotic interstitial pneumopathies. Collagenolytic activity of the alveolar fluid]

Collagenolytic enzyme release in alveolar structures is probably one of the initial events leading to impaired balance between collagen synthesis and degradation in the connective matrix of the lung, resulting in pulmonary fibrosis. The collagenolytic activity was determined in the bronchoalveolar fluid of 40 normal subjects or patients with miscellaneous pulmonary diseases and was found to be present in seventeen, viz.: 7/7 patients with interstitial fibrosis, irrespective of its origin: 4/4 patients with radiation pneumonitis; 4/15 patients with sarcoidosis and 2/2 patients with transient eosinophilic pneumopathy. There was no evidence of fibrosis in the 23 patients who showed no collagenolytic activity. Thus, collagenolytic enzymes are present in the alveolar structures of patients with interstitial pulmonary diseases of diverse origin capable of leading to fibrosis. Monitoring the release of this enzyme by bronchoalveolar lavage could be useful to evaluate the risk of fibrosis in such patients.