Protective effect of human granulocyte colony-stimulating factor on bacterial and fungal infections in neutropenic mice.

The in vivo effects of purified natural human granulocyte colony-stimulating factor (h G-CSF) on bacterial and fungal infections were examined in mice treated with cyclophosphamide (CPA). Induction of severe neutropenia was prevented by repeated daily injections of h G-CSF at a dose of 2.5 micrograms/day for 4 days after the CPA treatment. Although control mice died shortly after the bacteria inoculation at day 4, most of the mice in whom the numbers of blood neutrophils were restored by h G-CSF injections were saved from death. At the site of the bacteria inoculation in the h G-CSF-treated mice many mature neutrophils were observed to migrate in a dose-dependent way. Furthermore, the dose of antibiotics required for elimination of infections was proved to be much less in the h G-CSF treated mice than that in the non-treated mice. These findings indicate that h G-CSF can be used efficiently for prevention and treatment of bacterial and fungal infections, particularly in patients with neutropenia.