[Foamy alveolar macrophages in various lung diseases, and their origin in rabbit lungs].

The present studies were done to clarify the significance of foamy alveolar macrophages (FAM) in lung diseases, and the mechanism of the production of macrophages in rabbit lungs. Human subjects consisted of 18 normal volunteers (NV) and 47 patients with lung disorders: chronic bronchitis (CB), 7 cases; pulmonary fibrosis (PF), 8 cases; old pulmonary tuberculosis (OPT), 7 cases; lung cancer (LC), 20 cases; and bronchiectasis (BE), 5 cases. In each case, over 30 macrophages in the BALF were observed by transmission electron microscopy. There were no significant differences in the percentage of FAm in the BALF among NV, CB, and PF. Furthermore, OPT and LC were not significantly different. Many more FAM were seen in OPT and LC than in NV, CB, and PF (p < 0.005). The percentage of FAM obtained from BE was much higher than that from OPT and LC (p < 0.005). These results suggest that the grade of foamy change in macrophages differs among lung diseases. Three groups of rabbits were studied. Group I rabbits (n = 6) were control, Group II rabbits (n = 6) underwent bronchial clamping, and Group III rabbits (n = 6) underwent complete replacement of blood with saline. The number of macrophages and type II cells was much greater in Group II rabbits than in Group I rabbits. In Group III rabbits, the number of macrophages was lower than in Group I rabbits. In Group III rabbits, vacuole-like structures were seen in the cytoplasma of type II cells, but not from in macrophages. These findings suggest that anoxia and blood flow are important for the appearance of macrophages in alveolar space. Group III rabbits had few alveolar macrophages. Therefore, alveolar macrophages may be derived from monocytes in blood.