SUPEROXIDE PRODUCTION BY NEUTROPHILS IN CHILDREN WITH MALIGNANT-TUMORS TREATED WITH RECOMBINANT HUMAN GRANULOCYTE-COLONY-STIMULATING FACTOR

Background. Human recombinant granulocyte colony-stimulating factor (r hG-CSF), widely used to combat chemotherapy-induced neutropenia, stimu lates both in vivo and in vitro intra- and extracellular O-2(-) produc tion in human polymorphonuclear cells (PMNs). Patients and Methods. Tw elve patients with solid tumors or acute lymphoblastic leukemia were t reated during induced aplasia with rhG-CSF (5 mu g/kg/day). Intra- and extracellular O-2(-) production by PMNs isolated from these patients after 5 days of rhG-CSF therapy was assessed following both fMLP and P MA stimulation. Results. Ad patients showed a rise in PMN count; admin istration of rhG-CSF enhanced intra- and extracellular O-2(-) release after fMLP but not after PMA stimulation. Conclusions. rhG-CSF potenti ates in vivo O-2(-) production by PMNs stimulated with receptor-mediat ed agonists via G-protein (e.g. fMLP), but not by those stimulated wit h agonists that bypass receptors via protein kinase C (e.g. PMA).