Prestorage versus poststorage white cell reduction for the prevention of the deleterious immunomodulatory effects of allogeneic blood transfusion

Abstract

ECENTLY, the United Kingdom, Ireland, and Portugal announced plans to implement universal white blood cell (WBC) reduction of all transfused allogeneic cellular blood components to prevent the theoretical risk of transmission of new variant Creutzfeldt-Jakob disease (nvCJD) by transfusion. 1 France and Canada also announced plans to implement universal WBC reduction to enhance overall transfusion safety. Universal WBC reduction will confer 3 proven and several potential benefits to patients. The proven benefits are the prevention of alloimmunization to human leukocyte antigens; the prevention of transmission of cytomegalovirus (CMV); and the prevention of febrile, nonhemolytic transfusion reactions (FNHTR). z The potential benefits include the prevention of the deleterious effects of transfusionassociated immunomodulation 3-5 and of virus activation6; the reduction of the risk of transfusionassociated bacterial sepsis7; the prevention of transmission of leukotropic viruses other than CMV2; as well as the prevention of the theoretical risk of transmission of the agent of nvCJD by transfusion.1 The risk of transmission of nvCJD by transfusion is considered only a theoretical possibility currently in the United States, because a bovine spongioform encephalopathy epidemic in cattle and cases of nvCJD have not occurred in North America. Therefore, if a decision were to be made to implement universal WBC reduction in the United States, such a policy would probably be introduced not with an intent to prevent the transmission of nvCJD, but to reap other potential benefits from WBC reduction. Most of the published evidence regarding other potential benefits pertains to the prevention of the deleterious immunomodulatory effects of allogeneic transfusion, 3-5 and the public debate regarding the implementation of universal WBC reduction in the United States is likely to focus on an examination of the efficacy and cost-effectiveness of WBC reduction in preventing these potential adverse effects.