Post-transfusion purpura and isoimmune neonatal thrombocytopenia in the same family.

Post-transfusion purpura and isoimmune neonatal thrombocytopenia are rare and unusual syndromes leading to severe thrombocytopenia. In both disorders the PLA1 platelet antigen is involved in the pathogenesis. A 41-year-old woman with an obstetrical history of isoimmune neonatal thrombocytopenia in two of her children developed post-transfusion purpura following a transfusion of packed red blood cells. Despite the apparent link in these two disorders associated with the PLA1 platelet antigen, this is the first reported case of post-transfusion purpura and isoimmune neonatal thrombocytopenia occurring in the same family.