Modulation of Neutrophil‐Mediated Activity Against the Pseudohyphal Form ofCandida albicansby Granulocyte Colony‐Stimulating Factor (G‐CSF) Administered In Vivo

Renewed interest in neutrophil transfusions has emerged with the development and clinical use of granulocyte colony-stimulating factor (G-CSF). G-CSF not only increases neutrophil (polymorphonuclear leukocyte, PMNL) production but also modulates various physiological properties of PMNL. The effects of G-CSF on PMNL-mediated fungicidal activity were evaluated by administration of G-CSF (300 micrograms/day subcutaneously) to 5 healthy volunteers for 6 days. G-CSF significantly enhanced PMNL-mediated damage of Candida albicans pseudohyphae by 33% (P=.007) on day 2 and by 44% (P=.04) on day 6 at a 10:1 effector:target ratio. In contrast, the ability of PMNL to induce damage of hyphae from either Fusarium solani or Aspergillus fumigatus did not significantly change during the study period. These data demonstrate that G-CSF administered in vivo modulates PMNL-mediated fungicidal activity against the pseudohyphal form of C. albicans, thereby suggesting potential utility of G-CSF as a biologic response-modifying therapy in some opportunistic fungal infections.