Portal de Periódicos da CAPES

Glycoprotein Ib/IX complex is the target in rifampicin‐induced immune thrombocytopenia

2000; Wiley; Volume: 110; Issue: 4 Linguagem: Inglês

10.1046/j.1365-2141.2000.02299.x

1365-2141

Jaime Pereira, Patricia Hidalgo, Mauricio Ocqueteau, Marcelo Blacutt, Miguel Marchesse, Yih Nien, Luz María Letelier S, Diego Mezzano,

Heparin-Induced Thrombocytopenia and Thrombosis

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.