Role of the Lungs in Regulation of the White Blood Cell Level1

I agranulocytosis and related conditions the white blood cell level cannot be increased-or only slightly and fleetingly-by transfusion of large volumes of normal blood (1-3). Disappearance of infused white blood cells in the recipient was observed during exsanguination-transfusions in humans (4), in leukopenic cats (5) and eviscerated rabbits (6). Leucemic white blood cells rapidly disappeared after being infused into non-leukemic individuals or patients with a different type of leukemia (7-g). In cardiac catheterization studies in humans Bierman and associates (9, IO) found that most infused leucocytes disappeared in the pulmonary circulation. These same authors (IO, II) reported that the white cell filtering mechanism may be impaired in leukemic patients. Transfused stained (12-14) or P32-labeled (q-18) white blood cells were found to be rapidly deposited (in order of decreasing quantities) in the lungs, liver and spleen. In contrast to these findings Farr (19) reported that the bone marrow and lymphoid tissue were the main sites of removal of intravenously injected lymphocytes labeled with a fluorescent stain. Weidman and Bucher (20) and Braunsteiner, Giebisch, Kolder and Werner (21) perfused the lungs of rabbits and guinea pigs through the pulmonary artery with homologous and heterologous blood after washing out the residual blood with Ringer’s solution. They found a decreased white cell count after a single passage through the lungs. Weisberger, Guyton, Heinle and Storaasli (16) discussed the possibility that the mechanism which removes white cells from con-