Febrile and allergic reactions after transfusion of platelet concentrates

Febrile and allergic transfusion reactions are well-known side effects after transfusion of platelet concentrates. Febrile reactions are regularly accompanied by chills and rigor. Allergic reactions are mostly mild with local, sporadically general urticaria, but they can lead to a severe, life-threatening anaphylactic shock syndrome. The causative agent of allergic reactions cannot be characterized precisely in most of the cases. White cell-reactive alloantibodies of the recipient as well as accumulation of proinflammatory cytokines such as interleukin-1, interleukin-6 or tumor necrosis factor-alpha in the supernatant of platelet concentrates, mainly released during storage by contaminating leukocytes, play a causative role in febrile reactions. However, even after transfusion of leukocyte-reduced platelet concentrates, febrile transfusion reactions are less frequent, but still occur. This indicates that other mediators, either in the plasma or released by the platelets themselves, may also be inductors for these reactions. This review reports about clinical manifestations, treatment, and pathophysiology of nonhemolytic transfusion reactions and gives an overview of precautions that may be undertaken to prevent such reactions.