Changes in the Surface Morphology of Human Alveolar Macrophages Induced by Tobacco and Marijuana Smoking

Abstract

The alveolar macrophage (AM) is pleomorphic in shape, with complex surface folds and ruffles. Two morphologic types of human AM from nonsmokers were identified in scanning electron microscopic studies of fresh plastic-adherent mono layers: flat cells (55%) and round cells (45%). The assumption of a flat, or spread, cell shape was complete after 30 min in tissue culture, and was dependent on active cell metabolism. The flat cell appeared to be the more active phagocyte, and the round cell relatively quiescent. Distinct morphologic changes in individual cells in the population were found in specimens from tobacco and marijuana smokers. These studies demonstrate qualitative and quantitative heterogeneity of the human bronchoalveolar lavage AM population, and indicate that this population can change in response to chronic inhaled pollutant exposure.