What is Febrile non-hemolytic transfusion reaction?

Febrile non-hemolytic transfusion reaction is the most common type of transfusion reaction. It is a benign occurrence with symptoms that include fever but not directly related with hemolysis. It is caused by cytokine release from leukocytes within the donor product as a consequence of white blood cell breakdown.These inflammatory mediators accumulate during the storage of the donated blood, and so the frequency of this reaction increases with the storage length of donated blood. This is in contrast to transfusion-associated acute lung injury, in which the donor plasma has antibodies directed against the recipient HLA antigens, mediating the characteristic lung damage.