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Glycoprotein IIb/IIIa autoantigenic repertoire in chronic idiopathic thrombocytopenic purpura
Author(s) -
Hou Ming,
Stockelberg Dick,
Kdtti Jack,
Wadenvik Hans
Publication year - 1995
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.1365-2141.1995.tb05421.x
Subject(s) - antibody , glycoprotein , platelet , platelet membrane glycoprotein , epitope , immunology , medicine , microbiology and biotechnology , blocking antibody , chemistry , biology
Summary. The objective of the present study was to further disclose the autoantigenic repertoire carried by the platelet glycoprotein (GP) IIb/IIIa complex. IgG‐F(ab′) 2 fragments were prepared from two prototype ITP patients, and their ability to block the binding of GPIIb/IIIa reactive antibodies derived from other patients with ITP was evaluated using a modified MAIPA assay; a P1 A1 alloantiserum and 20 normal sera were included as controls. It was found that the two prototype IgG‐F(ab′) 2 fragments were each able to significantly block the binding of serum IgG to GPIIb/IIIa in six (55%) and seven (64%) out of 11 patients with chronic ITP, respectively. No significant blocking effect was observed for IgG‐F(ab′)2 fragments prepared from normal subjects. Also, the binding of the P1 A1 alloantiserum to its epitope on GPIIIa was not affected by any of the blocking IgG‐F(ab′)2 fragments exploited in the study. These data substantiate that in chronic ITP at least half of the GPIIb/IIIa reactive sera bind to homogenous autoepitopes.