Presence of fibronectin in pneumoconiotic lesions.

During the last 10 years our investigations have confirmed that collagen is not the major protein material in the lesions of progressive massive fibrosis of coal workers. In previous studies it was demonstrated that a substance similar in composition to fibrin was an important component in these masses. We report immunohistochemical studies on the lungs of seven coalworkers which show that the complex extracellular material in six of the lesions of massive fibrosis contains fibronectin. Preliminary observations indicate that fibronectin is also present in the lesions of silicosis and asbestosis.