Bronchoalveolar lavage in silicosis

In this report we describe the chronic effects of inhaled silica, a potent macrophage toxin, on cells which could be lavaged from the lung in man. Eight bronchoalveolar lavages were performed on patients with complicated silicosis, who had last been exposed to silica 1 to 12 years prior to lavage. We compared the results with those from 10 lavaged control subjects. All subjects in both groups were cigarette smokers.No differences were detected in cell number, viability, adherence or ability to phagocytize and killListeria monocytogenes, but significantly increased numbers of type II pneumocytes were present in lavages from the silicotic subjects. This finding probably indicates type II cell hyperplasia and provides indirect evidence of the continuing presence of biologically active material within the lung years after cessation of exposure to silica.