Lymphocyte subpopulations in bronchoalveolar lavage fluid in asbestos workers

We examined peripheral blood and bronchoalveolar lavage (BAL) fluid lymphocyte subpopulations in 29 asbestos workers, 10 with and 19 without clinical or radiologic evidence of asbestosis. Peripheral blood lymphocyte subpopulations were also measured in 13 control subjects. The mean OKT4:OKT8 (T-helper/inducer:T-suppressor/cytotoxic lymphocyte) ratio in BAL fluid in the 29 asbestos workers was 0.96 (range, not detected to 3.33), significantly less than 1.76 (1.33 to 2.67) in peripheral blood (p less than 0.001). There were no significant differences in OKT4:OKT8 ratios in peripheral blood between the 10 patients with asbestosis, the 19 asbestos workers without asbestosis, and the 13 normal control subjects or in the OKT4:OKT8 ratios in BAL fluid between patients with asbestosis and asbestos workers without asbestosis. In the group as a whole, 83% of those who had suffered more than 5 yr of exposure to asbestos showed OKT4:OKT8 ratios less than 1.2, whereas in those who had suffered fewer than 5 yr of exposure, 80% showed ratios greater than 1.2 (p less than 0.02). No other relationships between OKT4:OKT8 ratios and clinical, radiographic, or physiologic variables were observed.