Characteristics of alveolar cells and soluble components in bronchoalveolar lavage fluid from non-smoking aluminium potroom workers

Abstract

Aluminium potroom workers have been reported to develop severe pneumoconiosis and bronchial hyperreactivity. The influence of inhalation of aluminium oxide and fluorides on the alveolar milieu was studied by bronchoalveolar lavage (BAL) in 14 male non-smoking potroom workers; 28 non-smoking healthy volunteers served as controls. The total numbers, concentrations, and proportions of various alveolar cells did not differ between the groups. The concentrations of albumin and fibronectin in BAL fluid were significantly higher (p < 0.01 for both) in the exposed workers, reflecting an increased alveolar capillary permeability and an activation of alveolar macrophages (AMs). The concentration of angiotensin converting enzyme, another AM marker, was, however, decreased (p < 0.01) in the workers. The concentration of hyaluronan, a fibroblast marker, did not differ between the groups. AMs from workers had a decreased capacity (p < 0.05) to interact with yeast C3b particles but not to ingest them. The expression of HLA-DR and OKM1 on the cell surfaces of AMs were equal in the two groups. The BAL findings were not accompanied by restrictive lung disease in the workers. The fact that only a discrete alveolitis was found in the potroom workers may be due to a low grade of exposure to alumina and fluorides and to frequent use of respiratory protection equipment.