Modulation of functions of granulocytes by recombinant human GM-CSF and possible complications of GM-CSF therapy.

Besides its effect on bone marrow progenitors, GM-CSF is able to modulate functions of mature cells such as neutrophils. It inhibits random migration and chemotaxis through action on both cells and chemotactic factors, and stimulates oxidative metabolism as well as elastase release. Furthermore, it strongly enhances the response of the cells to the usual stimulants such as f-Met-Leu-Phe and phorbol esters. The role of neutral proteinases and activated oxygen species in different diseases such as ARDS, emphysema, coagulation defects, arthritis, and inflammation, is recognized. The remarkable in vitro release of neutral proteinases and activated oxygen species from granulocytes after GM-CSF stimulation may be of importance in vivo. This should be considered in clinical application of GM-CSF, particularly with high-dose therapy.