GRANULOCYTE-COLONY-STIMULATING FACTOR ENHANCES THE EXPRESSION OF CD62ON PLATELETS IN-VIVO

The expression of CD41, CD42 and CD62 on platelets was determined in t en patients with and without G-CSF treatment. CD41 and CD42 is express ed in nearly 100% of the platelets without change after G-CSF treatmen t. The expression of CD62 on the platelets' surface is significantly e nhanced by G-CSF indicating a depletion of the alpha-granules. No plat elet aggregation was observed. The enhanced secretion of thrombocyte-s pecific proteins does not induce aggregation but may promote ADP-induc ed aggregation. Furthermore, the surface-bound and soluble CD62 binds specifically to macrophages and endothelial cells and is involved in t he regulation of inflammatory processes. Thus indirect mechanisms may supplement direct effects of G-CSF after chemotherapy.