Impact of red blood cell alloimmunization on sickle cell disease mortality: a case series

BACKGROUNDAlthough red blood cell (RBC) transfusion represents an integral component of sickle cell disease (SCD) care, transfusion support for some patients can result in alloimmunization to RBC antigens. Alloimmunized patients with SCD appear to experience worse survival compared to nonalloimmunized patients. While this difference in mortality may in part be due to underlying immunologic differences related to disease severity, it may also reflect direct clinical consequences of RBC alloimmunization. Alloimmunized patients have an increased risk of serious hemolytic transfusion reactions (HTRs) and may not receive adequate RBC transfusion support due to lack of compatible RBC units. CASE REPORTThis study reports on five RBC alloimmunized patients with SCD who died, to illustrate the concept that RBC alloimmunization itself contributes to premature death. RESULTSThe clinical course for each of the reported patients provides insight into the direct and indirect consequences of RBC alloimmunization, where patients experienced delayed HTRs or did not receive needed RBC transfusions. CONCLUSIONFuture work examining the clinical impact of RBC alloimmunization should not only consider HTRs but should also address the potential consequences associated with difficulties in obtaining compatible blood.