Acquired Glanzmann's thrombasthenia without thrombocytopenia: a severe acquired autoimmune bleeding disorder.

Acquired Glanzmann's thrombasthenia (GT) is an uncommon accompaniment to immune thrombocytopenic purpura. Rarely, GT may present as an acquired autoimmune disorder of platelet function, with rapid onset of a moderate-to-severe bleeding tendency, a prolonged bleeding time, but with a normal platelet count and normal platelet glycoprotein (GP) expression. This is caused by an autoantibody with specificity for platelet GP IIb/IIIa or an epitope close to that of the GP, resulting in partial or complete refractoriness of the patient's platelets to ADP, collagen and arachidonic acid. We describe two patients with acquired GT and a normal platelet count, who presented with severe bleeding. The first patient responded gradually to immunosuppressive treatment but eventually developed non-Hodgkin's lymphoma. The second patient had no other underlying conditions and remitted spontaneously within 2 years.