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Measurement of von Willebrand factor binding to a recombinant fragment of glycoprotein Ib α in an enzyme‐linked immunosorbent assay‐based method: performances in patients with type 2B von Willebrand disease
Author(s) -
Caron Claudine,
Hilbert Lysiane,
Vanhoorelbeke Karen,
Deckmyn Hans,
Goudemand Jenny,
Mazurier Claudine
Publication year - 2006
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.2006.06095.x
Subject(s) - ristocetin , platelet glycoprotein gpib ix complex , von willebrand disease , von willebrand factor , platelet , platelet membrane glycoprotein , chemistry , glycoprotein ib , microbiology and biotechnology , recombinant dna , horseradish peroxidase , antibody , glycoprotein , enzyme , immunology , biochemistry , medicine , biology , gene
Summary Type 2B von Willebrand disease (VWD) is characterised by an increased affinity of von Willebrand factor (VWF) for its platelet receptor glycoprotein Ib (GPIb). This feature is usually studied in vitro by a ristocetin‐dependent VWF platelet‐binding assay, which has some limitations as it requires [e.g. (radio)‐labelled anti‐VWF antibodies and normal formaldehyde‐fixed platelets]. We, here, extended the applicability of an enzyme‐linked immunosorbent assay‐based method previously described for the measurement of ristocetin co‐factor activity that used a recombinant fragment of GPIb (rfGPIb α ) and horseradish peroxidase‐labelled rabbit anti‐human VWF antibodies for measuring the captured ristocetin‐VWF complexes on the rfGPIb α . Thirty‐one type 2B VWD patients from 15 families with eight different known mutations were studied. VWF in plasma from 28 of these patients bound better than normal VWF at 0·2 mg/ml ristocetin, with the ratio, optical density (OD) patient/OD normal pool plasma, higher than 1·8. For two of the three other patients with no enhanced response of plasma VWF, the platelet lysate VWF showed an enhanced binding capacity; for the last patient, the results in other members of the family are unequivocal. We conclude that, this new method for measurement of plasma or platelet VWF‐binding capacity offers great advantages for correct type 2B VWD diagnosis.