Effects of oral N-acetylcysteine on cell content and macrophage function in bronchoalveolar lavage from healthy smokers.

Bronchoalveolar lavage (BAL) was performed in fourteen healthy non-smokers and eleven healthy smokers. In smokers BAL was performed before and after eight weeks' treatment with N-acetylcysteine (NAC; 200 mg t.i.d.). Cell number, composition and viability were determined in the BAL fluid. Alveolar macrophages (AMs) were cultured before examination of their phagocytic capacity and their ability to produce leukotriene B4 (LTB4). BAL fluid from smokers contained more cells than that from non-smokers (p less than 0.001). This was mainly attributable to increases in both proportion and absolute number of AMs (p less than 0.001) and to an increase in absolute number of neutrophils (p less than 0.05). However, there was a decrease in proportion of lymphocytes in BAL fluid from smokers (p less than 0.001). Phagocytic capacity of adherent cells and capacity of AMs to generate LTB4 after stimulation with opsonized zymosan (OZy) were decreased in smokers (p less than 0.05 and p less than 0.01 respectively). NAC treatment of smokers did not affect cell number but resulted in an increased proportion of lymphocytes in BAL fluid (p less than 0.05). The phagocytic capacity of AMs was not significantly altered but was improved in five of eleven smokers after NAC treatment. NAC also enhanced the decreased LTB4 secretion by smokers' AMs (p less than 0.05). We conclude that smoking leads to reduced phagocytic capacity and LTB4 secretion of AMs and that oral NAC treatment may improve the function of AMs.