Thorax
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Bronchoalveolar lavage fluid from 43 patients with biopsy proved sarcoidosis and 10 control subjects were assayed for fibronectin and collagenase activity. Fibronectin was significantly increased in the group with sarcoidosis and was found to be positively correlated with angiotensin converting enzyme activity, protein concentration, percentage of T cells and helper:suppressor ratios in the lavage fluid. Increased fibronectin in the bronchoalveolar lavage fluid was not related to functional or radiographic indices of interstitial disease and did not identify patients subsequently requiring treatment. ⋯ Ten of 16 patients with bronchoalveolar lavage fluid collagenase had radiographic class III or IV disease and a disease duration of more than two years. On follow up 62% of patients with bronchoalveolar lavage fluid collagenase required subsequent treatment, compared with only 23% of patients without collagenase. These results indicate an association between bronchoalveolar lavage fluid collagenase and progressive, prolonged disease in sarcoidosis, whereas increased bronchoalveolar lavage fluid fibronectin is associated with indices of disease activity.