Post-transfusion purpura due to anti HPA–1a antibodies – a retrospective case report

Post-transfusion purpura is a life-threatening adverse reaction associated with a reduction in platelet counts below 10 x 109/L and bleeding. It usually occurs in women who, due to their pregnancies, have developed antibodies directed against human platelet antigen (HPA), most often anti-HPA 1a. The case described by us concerned an 83-year-old woman who received two units of red blood cells (RBC) due to severe secondary anemia. Seven days after the transfusion, she developed skin symptoms of thrombocytopenic diathesis, gastrointestinal bleeding, and a reduced number of platelets (3 x 109/L), and the patient’s serum (genotype HPA-1b/1b) was positive for anti-platelet antibodies with HPA-1a specificity and directed against human leukocyte antigen (HLA) class I and class II antibodies, unresponsive to the lymphocytotoxic test. Prompt diagnosis by our transfusion medicine consultant and the initiation of treatment with intravenous immunoglobulins certainly shortened the duration of thrombocytopenia and bleeding, and possibly also saved the patient’s life.