hematology and oncology
Thrombocytopenia: Other Causes
Blood transfusions
Posttransfusion purpura involves immunologic platelet destruction indistinguishable from Immune Thrombocytopenia (ITP) (ITP), except for a history of a blood transfusion within the preceding 7 to 10 days. The patient, usually a woman, lacks a platelet antigen (PLA-1) present in most people. Transfusion with PLA-1–positive platelets stimulates formation of anti–PLA-1 antibodies, which (by an unknown mechanism) can react with the patient’s PLA-1–negative platelets. Severe thrombocytopenia results, taking 2 to 6 weeks to subside. Treatment with IV immune globulin (IVIG) is usually successful. 