Thromb Haemost 2000; 83(01): 148-156
DOI: 10.1055/s-0037-1613771
Commentary
Schattauer GmbH

The Effect of Monoclonal Anti-human-platelet Antibodies on Platelet Kinetics in a Baboon Model: IgG Subclass Dependency

Lindi-Marie Coetzee
1   From the Department of Haematology and Cell Biology, Catholic University, Leuven, Belgium
,
Henry Pieters
1   From the Department of Haematology and Cell Biology, Catholic University, Leuven, Belgium
,
Veronica van Wyk
1   From the Department of Haematology and Cell Biology, Catholic University, Leuven, Belgium
,
Susan Cooper
2   Department of Anatomical Pathology of the University of the Orange Free State, Bloemfontein, South Africa, Catholic University, Leuven, Belgium
,
Jan Roodt
1   From the Department of Haematology and Cell Biology, Catholic University, Leuven, Belgium
,
Stefan De Reys
3   Laboratory for Thrombosis Research, Campus Kortrijk, Catholic University, Leuven, Belgium
,
Philip N. Badenhorst
1   From the Department of Haematology and Cell Biology, Catholic University, Leuven, Belgium
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Publikationsverlauf

Received 08. Dezember 1998

Accepted after resubmission 28. Juni 1999

Publikationsdatum:
06. Dezember 2017 (online)

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Summary

We assessed the in vivo effect of six intact anti-human antiplatelet antibodies of two major IgG subclasses on platelet kinetics in baboons. Five of the six antibodies tested caused thrombocytopenia of varying degree when injected at a precalculated threshold value. An agglutinating IgG1 antibody (MA-8L4A12) caused a long-lasting, mild thrombocytopenia with a predominant uptake of radiolabelled platelets in the spleen, while the four IgG2 antibodies tested (MA-13G8E1, MA-2M5A6, MA-21K2E8 and MA-22M10) caused a severe, transient thrombocytopenia with uptake of platelets in the liver. Two of the IgG2 antibodies (MA-13G8E1 and MA-2M5A6) caused platelet activation and aggregation in vitro, whilst the other two did not elicit a platelet aggregation response. The platelet survival time was shortened with all five of the thrombocytopenia-inducing antibodies, while only one antibody (MA-2M5A6) had a significant effect on the bleeding time. This study indicates that the IgG subclasss may be a determining factor in the outcome of platelet sequestration in immune-induced thrombocytopenia.