Abnormal bronchoalveolar lavage in asymptomatic dairy farmers. Study of lymphocytes

Bronchoalveolar lavage (BAL) was performed on 24 asymptomatic dairy farmers. Thirteen had serum precipitins to Micropolyspora faeni (MF) antigens (Group 1), and 11 were seronegative control subjects (Group 2). All were nonsmokers and had no history of previous lung disease. Thirteen of 24 subjects (9 in Group 1 and 4 in Group 2) had a high percentage of lymphocytes (greater than or equal to 20%) in their BAL. The T-lymphocyte subpopulations as estimated by OKT3, OKT4, and OKT8 monoclonal antibody reactivity were measured in peripheral blood lymphocytes; OKT3 = 58.5 +/- 15.6% for Group 1, and 58.5 +/- 8.7% for Group 2; OKT4 = 40.6 +/- 10.7% and 39.9 +/- 10.0%; OKT8 = 21.5 +/- 10.6% and 22.4 +/- 8.0%, respectively (p = NS). These lymphocyte characteristics were also similar when subjects with a high percentage of lymphocytes in BAL were compared to those with a normal percentage. Specific (MF-coated) chicken erythrocyte lymphocytotoxicity (Group 1, 45.2 +/- 29.5%, Group 2, 49.2 +/- 23.4%), and nonspecific lymphocytotoxicity (Group 1, 43.9 +/- 28.6%, Group 2, 37.9 +/- 18.0%) were also similar. We conclude that a large number of asymptomatic dairy farmers have an increased percentage of lymphocytes in their BAL ("alveolitis") and that peripheral blood lymphocytes in these subjects have normal subpopulations, as assessed by monoclonal antibodies, and normal lymphocytotoxicity.