The role of cytokines in blood transfusion reactions

Recent advance in the understanding of the mechanism of hemolytic transfusion reactions results from the investigation of cytokine generation in in vitro models of incompatible red blood cell transfusion. Cytokines with pyrogenic and pro-inflammatory activities as well as cytokines with activating properties for granulocytes, monocytes and endothelial cells are produced in both ‘intravascial’ and ‘extravascular’ types of hemolytic reactions. It has also been demonstrated that cytokines are generated and accumulated in blood components such as platelet concentrates, during storage. A large part of febrile transfusion reactions results from transfusion of stored platelet concentrates containing high cytokine levels and not from antigen-antibody reaction. Prestorage removal of white blood cells, which generate cytokines during storage, from platelet concentrates reduces strongly the reaction incidence and should be standard practice.