Relative efficacy of steroid therapy in immune thrombocytopenia mediated by anti‐platelet GPIIbIIIa versus GPIbα antibodies

Abstract

Immune thrombocytopenia (ITP) is characterized by platelet clearance mediated primarily by autoantibodies against the platelet GPIIbIIIa and/or GPIbα. Steroid therapy is a first‐line treatment for ITP. However, some patients are refractory to this therapy and currently no method can predict which patients will respond. To evaluate whether steroids are equally efficacious in treating patients with ITP caused by anti‐GPIIbIIIa versus anti‐GPIbα antibodies, we performed a retrospective study on 176 newly diagnosed patients with acute ITP who had severe bleeding symptoms and were admitted as resident patients to the hospital. The patients were treated first with intravenous administration of high‐dose dexamethasone (DXM), followed by oral administration of prednisone. Response to therapy was observed in a majority of patients with antibodies specific for GPIIbIIIa (31/43) or without detectable antibodies against either GPIIbIIIa or GPIbα (36/45). In contrast, the steroid response was significantly lower in patients with anti‐GPIbα antibodies (9/34) or with antibodies against both GPIbα and GPIIbIIIa (16/54). The preliminary findings of this study suggest that in future prospective clinical trials including corticosteroids, the anti‐GPIbα, and ‐GPIIbIIIa status should be assessed in order to test its potential relevance in deciding future treatments. © Wiley Periodicals, Inc.

High-dose dexamethasone vs prednisone for treatment of adult immune thrombocytopenia: a prospective multicenter randomized trial

“…24 Though not recommended as a diagnostic parameter in practice guidelines, 2,3 a test of antiplatelet autoantibodies showed certain prognostic potentials according to data from our study and others. 25,26 In conclusion, results from this prospective, multicenter, randomized, controlled study suggest that 1 or 2 courses of HD-DXM provides a more effective and more rapid response as initial treatment of ITP, with at least comparable long-term prognosis and better tolerance when compared with conventional PDN. HD-DXM also enables patients to For personal use only.…”

CD8+ T cells are predominantly protective and required for effective steroid therapy in murine models of immune thrombocytopenia

“…5 The primary platelet surface antigen targets are GPIIbIIIa (aIIbb3 integrin, 70-80% of patients). 2,6,7 Approximately 10% to 20% of patients do not respond to first-line therapies including steroids, 8,9 intravenous immunoglobulin G, 10,11 and anti-Rh(D). 4,10 Approximately 14% do not respond to splenectomy, and 20% of responders relapse within weeks to years.…”

Immune thrombocytopenia: antiplatelet autoantibodies inhibit proplatelet formation by megakaryocytes and impair platelet production in vitro

“…[39][40][41] However the effect on proplatelet formation appears to be independent of the antibody specificity.…”