Effect of exogenous recombinant human granulocyte and granulocyte-macrophage colony-stimulating factor on neutrophil function following allogeneic bone marrow transplantation

Functional activity of peripheral blood granulocytes was assessed in seven patients and in their normal donors following allogeneic bone marrow transplantation (BMT). Functions studied included superoxide generation (O₂^-), intracellular killing of Staphylococcus aureus, phagocytosis, and killing of Candida albicans. Neutrophils were tested following preincubation with 300 pM granulocyte-macrophage colony-stimulating factor (GM-CSF), 1.2 nM granulocyte colony-stimulating factor (G-SCF), or buffered solution (diluent) as control. Our data indicate that following BMT, both recipients and their normal donors show GM-CSF- and G-CSF-induced increases in: 1) O₂^- production in response to fMet-Leu-Phe (fMLP), 2) killing of S. aureus, and 3) phagocytosis of C. albicans. In two patients that showed low candidacidal activity, GM-CSF and G-CSF markedly enhanced the cytotoxic activity of the cells. Our studies indicate that GM-CSF and G-CSF increase 'oxygen-dependent' oxidative activities in neutrophils from BMT recipients and their normal donors and enhance the antimicrobial activity of the cells.