Fatal acute hemolytic transfusion reaction due to anti‐B from a platelet apheresis unit stored in platelet additive solution

BACKGROUND Hemolytic transfusion reactions from out‐of‐group plasma in platelet (PLT) transfusions are uncommon, with most involving passive transfer of anti‐A. Only rare reactions have ever been reported due to anti‐B. STUDY DESIGN AND METHODS An apheresis PLT product was donated by a blood group O male, processed using PLT additive solution, and pathogen reduced. Postreaction recipient testing included an antibody screen using gel technology, a direct antiglobulin test (DAT) using immunoglobulin G and C3, and an eluate against group O and B cells. Postreaction donor testing included measuring anti‐B titers in saline, with and without anti‐human globulin. RESULTS A 60‐year‐old blood group B patient with relapsed acute myeloid leukemia developed confusion, fever, and hypotension within hours after a blood group O PLT transfusion. The posttransfusion reaction evaluation was remarkable for a positive DAT 3+ for C3; the eluate showed anti‐B. Rapid extravascular hemolysis occurred, with a 50% decline in hemoglobin, a high lactate dehydrogenase, and a high bilirubin. She was resuscitated with fluids, blood products, pressors, and oxygen and died of asystole 60 hours later. The donor's anti‐B titers were 128 by tube testing at immediate spin and 512 at the anti‐human globulin phase. Notably, a group B patient at a different hospital received a split of the same apheresis unit, with no reaction. CONCLUSION To our knowledge, this is the first fatality reported from passively transfused anti‐B. The fact that one transfusion recipient died whereas another did not have any reported reaction highlights the potential importance of recipient variables in isohemagglutinin‐mediated hemolysis.