Evidence for a light chain restriction of glycoprotein Ib/IX and IIb/IIIa reactive antibodies in chronic idiopathic thrombocytopenic purpura (ITP)

Br J Haematol. 1995 May;90(1):175-9. doi: 10.1111/j.1365-2141.1995.tb03397.x.


To address the assumption of clonally restricted antibodies in immune thrombocytopenias we studied sera from 19 patients with chronic ITP known to possess antibodies reactive with glycoprotein (GP) Ib/IX and/or GPIIb/IIIa. These sera were re-analysed using the standard monoclonal antibody immobilization of platelet antigens (MAIPA) assay and 16 patients exhibited IgG antibodies reactive with GPIIb/IIIa; seven patients showed also a reactivity with GPIb/IX. Employing a light-chain-specific MAIPA assay, 75% (12/16) of these sera displayed GPIIb/IIIa-specific antibodies that were light chain restricted; only 13% (2/16) of the GPIIb/IIIa reactive sera showed a mixed kappa and lambda phenotype. A light-chain-restricted phenotype was also seen for the GPIb/IX reactive antibodies. To further substantiate these findings, the MAIPA assay was modified in order to avoid interference from human anti-mouse antibodies. A high frequency of light-chain restricted platelet antibodies was also found using the modified MAIPA technique. These results support the hypothesis of a clonal B-cell expansion in immune thrombocytopenias, producing antibodies with a restricted idiotype repertoire and reacting with a limited number of epitopes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Autoantibodies / immunology*
  • Clone Cells / immunology
  • Female
  • Humans
  • Immunoglobulin Light Chains / immunology*
  • Immunoglobulin kappa-Chains / immunology
  • Male
  • Middle Aged
  • Platelet Membrane Glycoproteins / immunology*
  • Purpura, Thrombocytopenic, Idiopathic / immunology*


  • Autoantibodies
  • Immunoglobulin Light Chains
  • Immunoglobulin kappa-Chains
  • Platelet Membrane Glycoproteins