Direct evidence for a bone marrow origin of the alveolar macrophage in man.

Alveolar macrophages were obtained from 23 patients who had received marrow transplants for hematologic disorders. The presence of a Y body in macrophages of male origin was demonstrated by fluorescence microscopy. In those patients with a marrow donor of opposite sex the alveolar macrophages were shown to be of donor origin. The disappearance with time of host macrophages indicates a life-span, under the conditions, of approximately 81 days.