Predictive value of bronchoalveolar lavage cells and serum precipitins in asymptomatic dairy farmers.

In 1981 to 1982, we reported that many (19/43) asymptomatic dairy farmers, especially those with positive serum precipitins, had a lymphocytic alveolitis. We reevaluated, six and seven years later, 33 of the initial 43 farmers to verify their outcome. The restudied group included 31 men and 2 women between 24 and 67 years of age. In both studies, 24 were nonsmokers and 9 were exsmokers. Each farmer answered a questionnaire, had a physical examination, blood withdrawal for precipitin analysis, a chest roentgenogram, and pulmonary function tests (forced expiratory flows and diffusion capacity). At restudy, one subject had developed symptoms suggestive of sub-acute farmer's lung and now had inspiratory crackles; six had chronic morning cough and sputum production. Serum precipitins were positive in 10 subjects, whereas 16 had been positive at the initial study. Precipitins reverted from positive to negative in eight subjects and from negative to positive in six. Chest roentgenograms were normal in 23 subjects, while discrete interstitial abnormalities were noted in nine. One subject had significant pulmonary infiltrates. Results of current pulmonary function tests were (% predicted, mean +/- SEM) DL(CO) 114.8 +/- 3.0, FEV1 108.1 +/- 2.4, FVC 105.4 +/- 1.1. No correlations were found between these data and the lymphocytes or mast cells found in the bronchoalveolar lavage (BAL) at the initial study of 1981 and 1982. We conclude that bronchoalveolar lavage cell counts of asymptomatic farmers have no long-term clinical significance.