Effects of granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor on neutrophil formation and function.

Work published in the past year has significantly increased our understanding of the intracellular signaling pathways that are activated following granulocyte-macrophage colony-stimulating factor or granulocyte colony-stimulating factor binding to cell surface receptors. The involvement of nonreceptor protein tyrosine kinases, in particular the JAK2 kinase, appears to be a major signal transduction pathway involved in the response to several hemopoietic cytokines. Further data continue to accrue on the clinical role of granulocyte colony-stimulating factor, in particular in the treatment of chronic neutropenia. Increased clinical experience with colony-stimulating factors has revealed side effects that may occur with chronic use. The effects of colony-stimulating factors on neutrophil function are shown increasingly to be complex and to involve significant interactions with other proinflammatory cytokines.