Asbestos fibers in bronchoalveolar lavage and lung tissue of former asbestos workers

Abstract

Bronchoalveolar lavage (BAL) provides a simple method of sampling inhaled particles deposited in the lower respiratory tract. We hypothesized that BAL could be used to measure the quantity and quality of lung asbestos burden. This would be true if BAL fluid asbestos fiber content reflected the total content as well as the size distribution of both uncoated and coated asbestos fibers in lung parenchyma. Therefore, we analyzed the asbestos fiber counts of 23 individual sample pairs in both BAL fluid and lung tissue samples obtained from 20 patients with occupational asbestos exposure using transmission electron microscopy (TEM). In addition, fiber type, fiber size, and aspect ratio were compared. Coated asbestos fibers were found in 10 of 23 BAL samples and 16 of 23 biopsies. The mean concentrations of coated asbestos fibers (i.e., asbestos bodies) in BAL and lung parenchyma showed a positive correlation (r = 0.75, p < 0.001). Likewise, the mean amphibole fiber concentrations correlated positively (r = 0.55, p < 0.01). However, there was no relationship between the mean chrysotile fiber counts in BAL and lung parenchyma (r = 0.18, p = 0.40). Asbestos fibers in lung tissue were significantly longer (8.2 +/- 0.5 versus 4.8 +/- 0.6 microns; p < 0.001) but had the same width (0.12 +/- 0.27 versus 0.11 +/- 0.15 microns; p = 0.24) when compared with those retrieved by BAL from the airspace compartment. The aspect ratio (dividing fiber length by width) was much higher in lung tissue than in BAL fluid (66.4 +/- 0.4 versus 42.9 +/- 0.5; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)