FIBROGENIC ACTIVITIES IN BRONCHOALVEOLAR LAVAGE FLUID OF FARMERS LUNG

Hyaluronic acid (HA), type III procollagen, fibronectin, and fibroblas t growth factors (FGF) were measured in 43 bronchoalveolar lavage flui d (BALF) specimens obtained from 38 patients with farmer's lung (FL) a nd in BALF of 9 nonexposed normal control subjects. Bronchoalveolar la vage was done in 21 farmers with acute FL (acute) and in 22 with a his tory of previous FL (Ex) who were still in daily contact with dairy ba rns. All farmers from the acute and Ex groups had a lymphocytic alveol itis, respectively, 62.7 (3.5) percent (mean [SEM]) and 48.1 (4.3) per cent. Hyaluronic acid, type III procollagen, fibronectin, and FGF were all highly increased in acute disease. These substances were also inc reased in the BALF of subjects of the Ex group who had no clinical sym ptoms or signs of acute disease at the time of lavage, but were active ly farming. The increase in type III procollagen, however, was less in this group than in the subjects with acute disease. These observation s suggest that the fibrosing activities and potentialities of the alle rgic alveolitis of FL are fully expressed at the time of clinical pres entation and also in the subclinical phase of the disease in susceptib le farmers who remain exposed after an initial acute phase of the dise ase.