Febrile non-hemolytic transfusion reaction is a type of transfusion reaction that is associated with fever but not directly with hemolysis. It is most commonly caused by antibodies directed against donor leukocytes and HLA antigens.More common in multi-transfused patients (in thalasemic patients) 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. Alternatively, FNHTR can be mediated by pre-formed cytokines in the donor plasma as a consequence of white blood cell breakdown.[1][2]