Thromb Haemost 2003; 89(03): 513-521
DOI: 10.1055/s-0037-1613382
Platelets and Blood Cells
Schattauer GmbH

CD32-dependent platelet activation by a drug-dependent antibody to glycoprotein IIb/IIIa antagonists

Donna L. Pedicord
1   Department of Chemical Enzymology, Department of Applied Biotechnology, Brystol-Myers Squibb Company, Wilmington, Delaware, USA
,
Ira Dicker
1   Department of Chemical Enzymology, Department of Applied Biotechnology, Brystol-Myers Squibb Company, Wilmington, Delaware, USA
,
Karyn O’Neil*1
,
Leah Breth
1   Department of Chemical Enzymology, Department of Applied Biotechnology, Brystol-Myers Squibb Company, Wilmington, Delaware, USA
,
Richard Wynn*2
,
Greogory F. Hollis*2
,
Jeffrey T. Billheimer
1   Department of Chemical Enzymology, Department of Applied Biotechnology, Brystol-Myers Squibb Company, Wilmington, Delaware, USA
,
Andrew M. Stern
1   Department of Chemical Enzymology, Department of Applied Biotechnology, Brystol-Myers Squibb Company, Wilmington, Delaware, USA
,
Dietmar Seiffert
1   Department of Chemical Enzymology, Department of Applied Biotechnology, Brystol-Myers Squibb Company, Wilmington, Delaware, USA
› Author Affiliations
Further Information

Publication History

Received 23 October 2002

Accepted after revision 07 January 2003

Publication Date:
09 December 2017 (online)

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Summary

Thrombocytopenia is observed with a frequency of up to 2% in patients treated with glycoprotein (GP) IIb/IIIa antagonists. We recently provided evidence that thrombocytopenia is caused by antibody binding to drug-induced conformational changes in GP IIb/IIIa. Here, we report that a murine monoclonal antibody binds to GP IIb/IIIa in an antagonist-dependent manner and activates platelets. Platelet stimulation is associated with a disruption of the phospholipid asymmetry, resulting in the assembly of catalytic active intrinsic Xase and prothrombinase complexes. Further mechanistic studies revealed that this response is (I) mediated in cis, (II) not associated with the formation of pro-thrombotic microparticles, and (III) requires intact platelet signaling and (IV) is blocked by increases in cAMP. The prothrombotic response is not observed using F(ab’)2 fragments and is blocked by incubation of platelets with neutralizing antibodies to the platelet FcγRIIa receptor (CD 32). Taken together, these observations suggest that GPIIb/IIIa antagonist-dependent antibody binding to the platelet fibrinogen receptor has the propensity to lead to CD32-mediated platelet activation and accelerated platelet clearance, leading to thrombocytopenia.

*1 present address: Centocor Inc., Malvern, PA


*2 present address: Incyte Genomics Inc., Newark, DE