Effects of in vivo administration of G-CSF on neutrophil functions in healthy volunteers.

The aim of the present study was to investigate the in vivo effects of granulocyte colony-stimulating factor (G-CSF) on neutrophil (PMN) function. G-CSF was administered once daily as s.c. injection for 6 d (d1-6) to healthy male volunteers. PMN migration (modified Boyden chamber), chemiluminescence (CL), adherence to nylon fibers and phagocytosis of IgG- and IgG-C3-coated particles were investigated before (d1), during (d2, d5) and 3 wk after G-CSF 7.5-10 micrograms/kg/d (n = 12). PMN surface expression of adhesion- and Fc gamma-receptors was measured on d1, d5, d8 and 3 wk after G-CSF 3-5 micrograms/kg (n = 12). Results obtained after G-CSF were compared to baseline using Wilcoxon's signed rank test. G-CSF induced PMNs showed a significantly (p < 0.05) decreased chemokinetic response (d5) as well as a reduced chemotaxis towards zymosan activated serum, FMLP and IL-8, respectively. Chemotaxis was reduced both at d2 and d5. Neutrophil adherence, phagocytosis and luminol-enhanced CL increased, whereas G-CSF had no effect on lucigenin-enhanced CL. G-CSF (3-5 micrograms/kg) caused an enhanced expression of CD11b, CD18, CD35, CD64 (Fc gamma RI) and CD32 (Fc gamma RII), respectively. We conclude that neutrophils produced in response to G-CSF have a reduced chemotaxis but an enhanced adherence and phagocytic capacity. G-CSF in vivo does not stimulate the respiratory burst.