Granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor: Comparisons and potential for use in the treatment of infections in nonneutropenic patients

Granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage co lony stimulating factor (GM-CSF) enhance the antimicrobial functions of mat ure neutrophils. G-CSF differs from GM-CSF in its specificity of action on developing and mature neutrophils, its effects on neutrophil kinetics, and its toxicity profile. The toxicity profile of recombinant (r) GM-CSF is con sistent with priming of macrophages for increased formation and release of inflammatory cytokines, whereas rG-CSF induces production of antiinflammato ry factors, such as interleukin-l receptor antagonist and soluble tumor nec rosis factor receptors, and is protective against endotoxin- and sepsis ind uced organ injury. The low toxicity of rG-CSF, results of animal models of infection, and extensive experience with neutropenic subjects have promoted clinical studies in nonneutropenic subjects, which indicate that rG-CSF ma y be beneficial as adjunctive therapy for treatment of serious bacterial an d opportunistic fungal infections in nonneutropenic patients, including tho se with alterations in neutrophil function.