Therapeutic Use of Cytokines to Modulate Phagocyte Function for the Treatment of Infectious Diseases: Current Status of Granulocyte Colony‐Stimulating Factor, Granulocyte‐Macrophage Colony‐Stimulating Factor, Macrophage Colony‐Stimulating Factor, and Interferon‐γ

The innate immune system represents the initial arm of host defense against pathogenic bacteria, fungi, and parasites. Neutrophils, monocytes, and tissue-based macrophages are major cellular components of this system. The potential ability to augment activity of the innate immune system has increased dramatically during the past 2 decades, with the discovery and development of cytokines. Four cytokines, namely granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), and interferon (IFN)-gamma, have received increasing attention as potential adjunctive agents for the treatment of infectious diseases. In various animal models of infection, therapeutic administration of each of the 4 cytokines has been shown to enhance pathogen eradication and to decrease morbidity and/or mortality. However, variable therapeutic efficacy has been reported in clinical trials conducted to date. This review summarizes the current status of the use of G-CSF, GM-CSF, M-CSF, and IFN-gamma in the treatment of infectious diseases.