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. Homotetramer. Interacts with TNFAIP6 (via Link domain). O-linked glycan consists of Gal-GalNAc disaccharide which is modified with sialic acid residues (microheterogeneity). Belongs to the intercrine alpha (chemokine CxC) family.