Bronchoalveolar lavage and clearance of 99m-Tc-DTPA in asbestos workers without evidence of asbestosis.

We performed BAL and measured the clearance of 99m-Tc-DTPA in 20 non-smoking subjects (mean age 50, range 36-68 years) occupationally exposed to asbestos (mean duration 14, range 3-30 years). All had normal lung function and none had clinical or radiological evidence of asbestosis. The mean BAL results were: total cells per ml 737 X 10(3) (360-1210), percentage macrophages 79 (49-96), percentage lymphocytes 13 (1-42), percentage neutrophils 8 (1-40), percentage eosinophils 0 (0-3), asbestos bodies per ml 83 (0-550). Eight subjects showed increased percentage of lymphocytes and four others showed increased percentages of neutrophils when compared with normal ranges in our laboratory. Higher percentages of neutrophils correlated with longer duration of exposure to asbestos (r = 0.54, P less than 0.025), and shorter time since last exposure to asbestos (r = -0.54, P less than 0.025). Four subjects showed faster clearance of 99m-Tc-DTPA than was observed in 31 normal non-smoking control subjects. There was a tendency for faster solute clearance to be associated with greater numbers of BAL macrophages (r = -0.39, P less than 0.10) but there were no significant relationships between solute clearance and other BAL variables. BAL profiles in asbestos workers may be abnormal in the absence of clinical or radiological evidence of asbestosis.