Asbestos bodies in bronchoalveolar lavage fluid and in lung parenchyma

Numerical concentrations of asbestos bodies (AB) were measured by light microscopy both in samples of bronchoalveolar lavage (BAL) fluid and in samples of lung parenchyma from 69 patients with suspected asbestos-related diseases who had had lavages and later open lung biopsies or autopsies. Objectives were to study the recovery of pulmonary AB by BAL and the ability of BAL concentrations to predict parenchymal concentrations. BAL and parenchymal concentrations were both spread over 6 orders of magnitude and were positively correlated (r = 0.74 between logarithmic values). It is believed that, by a process of progressive elution, AB firmly adherent to the alveolar wall become suspended in BAL fluid; such suspended bodies represent roughly 2% of all the bodies stored in the portion of lung lavaged. Recovery is associated with great interindividual variations. When a measured BAL concentration exceeds 1 AB/ml, it can be quite confidently predicted, however, that the parenchymal concentration is in excess of 1,000 AB/g and that the patient has experienced a nontrivial asbestos exposure.