Quinine- and Quinidine-dependent Antiplatelet Antibodies: REQUIREMENT OF FACTOR VIII-RELATED ANTIGEN FOR PLATELET DAMAGE AND FOR IN VITRO TRANSFORMATION OF LYMPHOCYTES FROM PATIENTS WITH DRUG-INDUCED THROMBOCYTOPENIA

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Abstract

The requirement of Factor VIII-related antigen (VIIIR:Ag) for platelet damage by quinine-and quinidine-dependent antibodies was studied in platelet-rich plasma (PRP) of four patients with severe von Willebrand's disease (vWd) (Factor VIII deficiency). Platelet factor 3 availability, platelet aggregation, and release of [14C]serotonin from labeled vWd-PRP by drug-dependent antibodies were significantly reduced in comparison with PRP from normal controls. Addition of purified VIIIR:Ag restored levels of platelet damage to that of normal PRP. In vWd-PRP, platelet damage by two human antiplatelet sera, not dependent on drugs, and by a rabbit antiplatelet serum did not differ from that in normal PRP. PRP from patients deficient in Factor VIII coagulant activity, Factor IX, or Factors II, VII, IX, and X behaved like normal PRP.

Authors

Sharron L. Pfueller, Pari K. Hosseinzadeh, Barry G. Firkin