Febrile transfusion reaction caused by AB0-incompatible platelet transfusion.

A febrile transfusion reaction caused by strong isoagglutinins in the patients serum is reported. The reaction resulted from a transfusion of group A platelets in a group 0 patient; the recipients' serum contained high titered isohemagglutinin (Anti-A 1:8192) capable of lysing bloodgroup A1 red cells up to a titer of 1:8. Moreover, the serum showed a strong positive thrombocytotoxic reaction with the platelets of the donor and some other group A individuals, but remained negative with group 0, and turned to negative reaction with group A samples after neutralization with bloodgroup substance. We conclude that pretransfusion testing of group 0 donors and recipients for isohemolysins combined with platelet crossmatching may prevent febrile reactions.