PF4 and Arterial thrombosis: Heparin forms complexes with platelet factor 4 and the Immunoglobulin G antibody for them, referred to as the HIT antibody [10-12]. The HIT antibody activates platelets through the bond to heparin and platelet factor 4 complexes with a resulting decrease in the platelet count by wasting [13]. The HIT antibody is also reported to activate monocytes and neutrophils (pan-cellular activation), causing arterial thrombosis (70%) and venous thrombosis (30%) by endothelial cell injury [14].