Fever is a symptom that occurs in a number of categories of transfusion reactions. It can also be associated with the patient's underlying condition. If the transfused patient develops a fever (usually defined as at least a 1°C rise from the baseline) during or after the transfusion of blood components, the patient must first be assessed for a hemolytic reaction. If the laboratory assessment for hemolysis is negative, then a culture is usually requested to rule out a bacterially contaminated blood component. When other sources of the fever have been ruled out, the reaction is categorized as a nonhemolytic febrile transfusion reaction (NHFTR). Multiply-transfused patients and multiparous women comprise the largest population experiencing this type of reaction.
There are two mechanisms involved in the manifestation of an NHFTR. The first involves the presence of a white cell antibody in the patient's plasma that interacts with antigens on platelets or leukocytes in the blood product. These antibodies may be directed against granulocyte antigens or human leukocyte antigens (HLA). This interaction causes endotoxins to be released, which act on the hypothalamus and stimulate a fever. The second mechanism involves the generation of leukocyte cytokines during product storage. Using prestorage leukocyte-reduced blood components will reduce or eliminate the possibility of NHFTR.
