Granulocyte colony-stimulating factor enhances the expression of CD62 on platelets in vivo

The expression of CD41, CD42 and CD62 on platelets was determined in ten patients with and without G-CSF treatment. CD41 and CD42 is expressed in nearly 100% of the platelets without change after G-CSF treatment. The expression of CD62 on the platelets' surface is significantly enhanced by G-CSF indicating a depletion of the alpha-granules. No platelet aggregation was observed. The enhanced secretion of thrombocyte-specific proteins does not induce aggregation but may promote ADP-induced aggregation. Furthermore, the surface-bound and soluble CD62 binds specifically to macrophages and endothelial cells and is involved in the regulation of inflammatory processes. Thus indirect mechanisms may supplement direct effects of G-CSF after chemotherapy.