The unique immunological features of heparin‐induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a serious drug reaction that leads to a decrease in platelet count and a high risk of thrombosis. HIT patients produce pathogenic immunoglobulin G (IgG) antibodies that bind to complexes of platelet factor-4 (PF4) and heparin. HIT immune complexes crosslink Fc-receptors resulting in platelet and monocyte activation. These events lead to the release of procoagulant chemokines and tissue factor, which …