Anti-E alloimmunization from a platelet apheresis transfusion in a 22-month-old male with acute myeloid leukemia.

RhD alloimmunization from platelet transfusions have been documented in the literature. However, non-RhD platelet alloimmunization is much less frequent and the risk for non-RhD alloimmunization from platelets is thought to be extremely low and most associated with buffy coat pooled platelets. A 22-month-old male with acute myeloid leukemia received 99 mL apheresis platelets for thrombocytopenia. Three months later, an antibody screen, the direct antiglobulin test (DAT), and red blood cell (RBC) genotype were sent for laboratory evaluation. The antibody screen was positive, with anti-E identified. The DAT was negative and the RBC genotype of the patient was predicted to be negative for the E antigen whereas the platelet donor was predicted to be positive for E antigen. There is a risk of alloimmunization of non-RhD antigen from platelet pheresis transfusion even in a patient less than 2 years old.