The incorporation of radioactive phosphorus into the phospholipids of human leukemic leukocytes and platelets.

The phospholipid composition of human platelets and erythrocytes has been reported by several investigators (1-4) and the metabolism of phospholipids in human blood has been studied in some detail (5-9). Recent investigations of phospholipid metabolism of leukocytes have been reported (6, 10) but we are not aware of similar studies on platelets. In this laboratory, investigation of the biochemical characteristics of leukemic leukocytes is being carried out, and as part of this program an examination of the phospholipid metabolism of these cells was undertaken. In this report are presented data on the phospholipid composition of platelets and leukocytes from leukemic patients, and the results of studies on the incorporation of P32-labeled orthophosphate (P32) into the phospholipids of these formed elements in vivo and in vitro. The phospholipid composition was similar in leukocytes and platelets from chronic leukemia and in leukocytes from acute leukemia. The pattern of incorporation into leukocyte phospholipids of p32 administered therapeutically to patients with chronic myelocytic leukemia was studied, and it was found that rapid incorporation of P32 could be demonstrated in lecithin, phosphatidylethanolamine, phosphatidylserine, inositol phosphatide, and sphingomyelin. In the course of this work it was