Proteolytic activities in bronchoalveolar lavage fluid of interstitial lung diseases: correlation to stage and prognosis.

In 18 patients with sarcoidosis, 10 patients with idiopathic pulmonary fibrosis (IPF), 6 patients with exogen allergic alveolitis (EAA), and 9 control persons we investigated proteolytic activities in bronchoalveolar lavage fluid (BALF). In lymphocyte-macrophage alveolitis (i.e. sarcoidosis and EAA) proteolytic activities in BALF were low, but the activities correlated with lung function deterioration within 1 year. In IPF (i.e. in neutrophil alveolitis) we found a striking correlation between proteolytic activities and stage of disease: high activities correlated with early stages, lower values with late stages of IPF. Measurement of proteolytic activity in BALF seems to be of interest to differential diagnosis and to prognosis of interstitial lung disease.