Glycoprotein Ib/IX complex is the target in rifampicin-induced immune thrombocytopenia
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Date
2000
Journal Title
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Volume Title
Publisher
BLACKWELL SCIENCE LTD
Abstract
Thrombocytopenia is a major adverse effect of several drug treatments. Rifampicin has been recognized as a cause of immune thrombocytopenia during intermittent high-dose therapy. We characterized the antibody of a patient who presented with purpura and thrombocytopenia during treatment of tuberculosis with rifampicin. Drug-dependent binding of the antibody to platelets was demonstrated by flow cytometry. In a glycoprotein-specific immunoassay, the binding epitope of the IgG antibody was found in the glycoprotein Ib/IX complex, using four different monoclonal antibodies (mAbs) against various epitopes on the GPIb/IX complex, as well as mAbs against GPIIb/IIIa, GPIa/IIa and GPIV. By immunoprecipitation of biotin-labelled platelets, reactivity of the antibody with GPIb/IX was found only in the presence of the drug. These findings clearly demonstrate that rifampicin induces the formation of drug-dependent antibodies capable of causing thrombocytopenia. The binding site of the rifampicin-dependent antibody, located in the GPIb/IX complex, seems to be a favoured target for antibodies induced by different drugs.
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Keywords
thrombocytopenia, immune-mediated, drug-dependent, drug-induced, glycoprotein Ib/IX, MONOCLONAL-ANTIBODY, IB-IX