Granulocyte colony-stimulating factor prevents ethanol-induced impairment in host defense in septic rats

Ethanol is a potent immunosuppressive agent that impairs neutrophil effector function. The purpose of this study was to determine whether granulocyte colony-stimulating factor (G-CSF), a cytokine that increases neutrophil number and functional activity, could prevent the ethanol-induced impairment of antibacterial host defense. Rats were injected with human recombinant G-CSF for 2 days. Eight hr after the last injection of G-CSF, animals were infused with ethanol (or saline) for 1 hr before the subcutaneous injection of live Escherichia coli. The infusion of alcohol was continued after the bacterial challenge and produced blood alcohol levels of 275-300 mg/dl. In control animals, the injection of E. coli resulted in a marked leukopenia. There was an influx of leukocytes into the subcutaneous space where the bacteria were injected, and neutrophil accumulation in tissues adjacent to the focus of infection (i.e., dorsal skin and muscle). Based on myeloperoxidase activity, there was no detectable accumulation of neutrophils in other soft tissues. In acutely intoxicated rats, leukocyte migration to the inflammatory site was impaired, and the number of viable bacteria isolated from the subcutaneous pocket was markedly increased. G-CSF prevented the sepsis-induced leukopenia, increased the influx of neutrophils in to the infection site, reduced the number of bacteria in the subcutaneous lavage fluid, and decreased the incidence of bacteremia in ethanol-treated rats when compared with rats not receiving G-CSF. These results demonstrate that G-CSF is a potent immunomodulator that stimulates neutrophil recruitment selectively to the site of infection and that can be used to ameliorate the ethanol-induced impairment in bacterial host defense.