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Platelet antibodies of the IgM class in immune thrombocytopenic purpura

Journal Article · · J. Clin. Invest.; (United States)
DOI:https://doi.org/10.1172/JCI111814· OSTI ID:5126423

The clinical course and response to therapy of patients with immune thrombocytopenic purpura (ITP) are not completely determined by the level of IgG present on the platelet surface. It is possible that antibodies of other immunoglobulin classes also play a role in platelet destruction in some of these patients. Therefore, the authors studied 175 patients with ITP for the presence of IgM anti-platelet antibodies using radiolabeled polyclonal or monoclonal anti-IgM. They observed that 57% of patients with clinical ITP had increased levels of IgM on their platelets, compared with normal controls and patients with thrombocytopenia who did not have ITP. They obtained similar results using either radiolabeled polyclonal or monoclonal anti-IgM, reagents whose integrity was first characterized using erythrocytes coated with defined amounts of IgM antibody. Among patients with increased platelet-IgM there was a significant correlation both with the presence of increased platelet-C3 as well as the amount of platelet-C3. The authors demonstrated the presence of warm-reacting IgM anti-platelet antibodies in the plasma of two of these patients who were further studied. These studies demonstrate the presence of warm-reacting IgM anti-platelet antibodies in some patients with ITP. They suggest that the binding of complement to platelets by IgM antibodies may initiate platelet clearance as well as enhance the effect of IgG antibodies in ITP.

Research Organization:
Hospital of the Univ. of Pennsylvania, Philadelphia
OSTI ID:
5126423
Journal Information:
J. Clin. Invest.; (United States), Journal Name: J. Clin. Invest.; (United States) Vol. 4; ISSN JCINA
Country of Publication:
United States
Language:
English