Delayed hemolytic transfusion reaction due to anti-Fy^b caused by a primary immune response: a case study and a review of the literature

Delayed hemolytic transfusion reactions (DHTRs) usually occur between 3 and 14 days posttransfusion as a result of a secondary immune response, with a drop in Hb level, fever, jaundice, or hemoglobinuria. DHTRs caused by a primary immune response are particularly rare events, and only a few reports have been known. In this report, we describe an unusual case of a DHTR caused by anti-Fy^b in a 42-year-old man, who had no prior history of transfusion. Although it seems to be a rare phenomenon, we suggest that DHTRs by a primary immune response may be considered even in the case of the patient who had typical evidence of hemolysis but who had no previous transfusion history.