The epitope specificity of heparin‐induced thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is caused by antibodies (HIT-Abs) that bind to a complex of heparin and platelet factor 4. We investigated the epitope specificity of the HIT-Abs, and found that the HIT-Abs recognized solid-phase immobilized complexes with an optimum ratio of four to eight molecules of PF4 per molecule of heparin. To try to define the epitopes within the PF4 molecule, intact and reduced (linearized) PF4 was tested against …