The effect of cytotoxic drugs on neutrophil phagocytosis in vitro and in patients with acute myelogenous leukaemia.

The in vitro effects of a range of concentrations of cyclophosphamide, doxorubicin, actinomycin D, cytarabine and methotrexate on neutrophil phagocytosis of C. albicans was studied. The reduction in phagocytic index (PI) was inversely proportional to the dilution of the drug and there was some inhibition of phagocytosis at all dilutions of all drugs. In patients with acute myelogenous leukaemia (AML), in vivo experiments showed that remission chemotherapy of doxorubicin or daunorubicin together with cytosine arabinoside increasingly inhibited phagocytosis over the period studied. The importance of these findings in the chemotherapy of malignant disease and the possible mode of action of cytotoxic drugs are discussed.