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Autoantibodies against platelet glycoprotein Ib/IX: a frequent finding in autoimmune thrombocytopenic purpura
Author(s) -
Kiefel V.,
Santoso S.,
Kaufmann E.,
MuellerEckhardt C.
Publication year - 1991
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.1365-2141.1991.tb04530.x
Subject(s) - autoantibody , epitope , platelet membrane glycoprotein , antibody , monoclonal antibody , medicine , platelet , immunology , glycoprotein , antigen , microbiology and biotechnology , biology
Summary Many autoantibodies involved in the pathogenesis of autoimmune thrombocytopenic purpura (AITP) are directed against epitopes on platelet glycoproteins (GP). These autoantibodies are a specific diagnostic characteristic of patients with AITP. In this study, the relative frequency of antibodies against GPs IIb/IIIa and Ib/IX was assessed in sera from 81 AITP patients with a glycoprotein‐specific enzyme immunoassay (MAIPA assay) using monoclonal antibodies against these platelet GPs. All sera contained platelet‐specific antibodies which had been detected by platelet immunofluorescence. Of the 81 antibodies tested, 58 (72%) reacted with at least one of the platelet GPs studied. Autoantibodies against GPIb/IX were as common as antibodies against the GPIIb/IIIa complex. The same ratio of specificities was observed on autologous platelets of an independent cohort of 29 patients. The epitope of three autoantibodies against GPIb/IX and of mab Gi10, a monoclonal antibody, which inhibits binding of these autoantibodies, was further characterized. Severity of thrombocytopenia was not related to the GP specificity of the autoantibody. The observation that in 23 (28%) of these sera the antigenic determinants could not be assigned to the glycoproteins under investigation suggests that platelet autoantibodies may react with other GPs or other membrane constituents, e.g. glycolipids.