Thromb Haemost 2001; 85(05): 821-823
DOI: 10.1055/s-0037-1615754
Review Article
Schattauer GmbH

Clonal Restriction of Platelet-associated Anti-GPIIb/IIIa Autoantibodies in Patients with Chronic ITP

Robert McMillan
1   The Scripps Research Institute, La Jolla, California, USA, and the University of Oklahoma, Oklahoma City, Oklahoma, USA
,
Jennifer Lopez-Dee
1   The Scripps Research Institute, La Jolla, California, USA, and the University of Oklahoma, Oklahoma City, Oklahoma, USA
,
Ronald Bowditch
1   The Scripps Research Institute, La Jolla, California, USA, and the University of Oklahoma, Oklahoma City, Oklahoma, USA
› Author Affiliations

Supported by grants M01-RR00833 and HL61809 from the U.S. Public Health Service
Further Information

Publication History

Received 19 October 2000

Accepted after revision 08 December 2000

Publication Date:
11 December 2017 (online)

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Summary

Chronic immune thrombocytopenic purpura is due to platelet destruction induced by autoantibodies against platelet surface antigens. Prior studies show that some serum autoantibodies are light-chain restricted, suggesting a clonal origin. Since plasma and platelet-associated antibody from the same patient may bind to different epitopes, it is important to evaluate the clonality of platelet-associated antibody. Platelet-associated autoantibodies from 28 ITP patients were studied. Of 23 platelet-associated antibodies tested directly, 16 showed significant light chain restriction (7 complete and 9 partial) when compared to plasma IgG light chain distribution. Similarly, 9 of 12 platelet-associated antibody eluates were light chain restricted, 5 complete and 4 partial. In all cases where platelet-associated antibody and antibody eluate from the same patient were studied, the results were concordant. We conclude that a significant proportion of platelet-associated antibodies from ITP patients show apparent clonality, as evaluated by light chain restriction. These results are consistent with other studies in ITP suggesting a limited antigenic repertoire.