Plasmacytoid monocytes appear in the bronchoalveolar lavage: Differences between smokers and nonsmokers

The primary purpose of this study was to describe the expression pattern of the surface antigens CD68, CD36, 27E10, G16/1, and RM3/1 on bronchoalveola r lavage (BAL) cells of smokers and nonsmokers. We found a cell type, morph ologically similar to lymphocytes, which showed a strong expression of the monocyte markers CD68 and CD36. We therefore recognized these cells as plas macytoid monocytes (PM). Hereby we report the appearance of PM in the BAL a nd its dependency of smoking. The study was conducted in 40 patients with v arious lung diseases and no, mal subjects. Sixteen patients and normal subj ects were smokers and 24 were nonsmokers. There was a significant increase of Phl in the BAL of smokers compared to nonsmokers. However we could not f ind a disease-related increase of PM in the BAL. This is the first report d emonstrating the occurence of PM in the BAL. Our data support the monocytic origin of PM and suggest an involvement in T cell-mediated responses of th e lung.