ANALYSIS OF FERRUGINOUS BODIES IN BRONCHOALVEOLAR LAVAGE FROM FOUNDRYWORKERS

Classical ferruginous bodies in tissue samples are considered to be ma rkers of past exposure to asbestos. Recent studies have shown that the presence of ferruginous bodies in bronchoalveolar lavage (BAL) fluid correlates with past exposure to asbestos and offers a more sensitive reference than occupational history. Lavage samples from five subjects who had worked in foundries were evaluated by light microscopy for th e presence of ferruginous bodies and by transmission electron microsco py for both characterisation of the uncoated fibre burden and analysis of the cores of the ferruginous bodies. All samples at lower magnific ation (light microscopy (200 x)) contained ferruginous bodies that wer e externally consistent with asbestos bodies. At higher magnification (400 x), a separate population from this group could be identified by the presence of a thin black ribbon. Transmission electron microscopy of the core materials of ferruginous bodies and comparable uncoated pa rticulates supported the reliability of higher magnification light mic roscopy for distinguishing most of those non-asbestos cores; however, a population of transparent non-asbestos cored ferruginous bodies were also shown to exist.