FARMERS LUNG - LONG-TERM OUTCOME AND LACK OF PREDICTIVE VALUE OF BRONCHOALVEOLAR LAVAGE FIBROSING FACTORS

This study evaluates the long-term outcome of farmer's lung (FL), addi ng high-resolution computed tomograms (HRCT) to previously reported pr ocedures and verifying whether bronchoalveolar lavage (BAL) fluid mark ers or substrates of fibrosis (hyaluronic acid, Type III procollagen, fibronectin, and fibroblast growth factors) (FF) predict outcome. A to tal of 33 subjects with a history of FL dating back at least 6 yr were evaluated with pulmonary function tests, chest x-ray (CXR), and HRCT. All subjects had an initial evaluation, which included a BAL, 6 yr be fore the current study. Subjects were then either in acute FL (n = 19) or in clinical remission despite continued contact (n = 14). In the c urrent study, pulmonary function tests revealed an obstructive profile in 13 subjects, restrictive changes in 1, an isolated decrease in lun g diffusion capacity in 3, and normal values in 16. Chest radiographs (CXR) were normal in 22 subjects, abnormal with interstitial or reticu lonodular changes in 6, and suggestive of emphysema in 5. HRCT reveale d emphysema in 9 subjects; 3 had localized fibrotic changes, 2 a groun d-glass pattern, and 19 were normal. There was a good correlation betw een the findings on pulmonary function tests and HRCT, however, CXR al one did not suggest the existence of emphysema in 4 subjects who had s uch findings on HRCT. No correlations were found between most outcome parameters and the level of the BAL FF measured 6 yr previously. We co nclude that airflow obstruction with or without emphysema is an import ant long-term sequela of FL and that BAL FF do not predict outcome in this disease.