Released during platelet aggregation. Neutralizes the anticoagulant effect of heparin because it binds more strongly to heparin than to the chondroitin-4-sulfate chains of the carrier molecule. Chemotactic for neutrophils and monocytes. Inhibits endothelial cell proliferation (By similarity). Homotetramer. Interacts with TNFAIP6 (via Link domain). Belongs to the intercrine alpha (chemokine CxC) family.