DIFFERENCES IN BRONCHOALVEOLAR CELL RESPONSE TO NITROGEN-DIOXIDE EXPOSURE BETWEEN SMOKERS AND NONSMOKERS

We have previously reported on the bronchoalveolar inflammatory effect s of the common air pollutant NO2 in nonsmokers. In this study, we hav e investigated these effects in tobacco smokers. Eight young nonbronch itic smokers and, as a reference group, eight healthy lifetime nonsmok ers were exposed to 3.5 ppm NO2 for 20 min. Bronchoalveolar lavage (BA L) was performed 3 weeks before and 24 h after exposure. The first rec overed 20 ml was analysed separately and defined as the bronchial port ion (BP), and the following fluid recovered as the bronchoalveolar por tion (BAP). Before exposure, the smokers had significantly less CD3+ c ells and more alveolar macrophages (AMs) in the BP and the BAP, as wel l as reduced AM phagocytosis in vitro compared to nonsmokers. After NO 2 exposure, the smokers reacted with an increase of AMs and neutrophil s in BAP. Nonsmokers reacted with an increase of neutrophils in BP, an increase of lymphocytes in BAP, and a tendency to reduced AM phagocyt osis. In summary, young smokers and nonsmokers differed to some extent in their reactions to NO2 exposure. This is probably due to the pre- existing airway inflammation and compensatory mechanisms to oxidant st ress in the smokers.