Flow cytometric quantification of phagocytosis in acute myeloid leukemia

Phagocytosis was studied by flow cytometry (FCM) in 15 patients with acute myeloid leukemia (AML). The pattern of phagocytosis differed markedly between AML and controls. The percentage of phagocytosing AML leukocytes was below that of the controls (p < 0.01). The phagocytic capacity of a subpopulation of leukemic cells was diminished, but compensated by the phagocytosis of a few prey by each of many immature leukocytes. Phagocytosis by immature and mature AML leukocytes was receptor dependent, and both carried functional complement receptors. Attachment to the cell surface was not rate-limiting in phagocytosing AML leukocytes.