A comparison of alveolar macrophages and pulmonary surfactant(?) Obtained from the lungs of human smokers and nonsmokers by endobronchial lavage

Endobronchial lavage was performed on eight smokers and eight nonsmokers. Centrifugation of lavage fluid produces a sediment consisting of two layers, a lower compact brown layer containing cells and an upper flocculent white layer. The brown layers from the smokers were greater in volume than those from the nonsmokers. Macrophages constituted about 93% of the cells from the smokers and about 63% of the cells from the nonsmokers. These data suggest that more free macrophages occur in the lungs of smokers than nonsmokers. In addition, many of the macrophages obtained from the smokers were filled with cytoplasmic inclusions. The volumes of white layers from the smokers were smaller than those from the non‐smokers. One white layer obtained from a nonsmoker was examined in a Wilhelmy balance and proved to be surface‐active. This may suggest that surface‐active material, pulmonary surfactant, is reduced in lavage fluids from smokers.