Mechanisms of severe transfusion reactions

Serious adverse effects of transfusion may be Immunologically or non-immuno logically mediated. Currently, bacterial contamination of blood products, p articularly platelets, is one of the most significant causes of transfusion -related morbidity and mortality. Septic transfusion reactions can present with clinical symptoms similar to immune-mediated hemolytic transfusion rea ctions and transfusion-related acute lung injury. Extremely high fever and/ or gastrointestinal symptoms, in a transfusion recipient, may be indicative of sepsis. The diagnosis is based upon culturing the same organism from bo th the patient and the transfused blood component. Numerous organisms have been implicated as the cause of septic transfusion reactions. Due to differ ent storage conditions, gram negative organisms are more often isolated fro m red blood cell components; gram positive organisms are more often isolate d from platelets. Prevention of septic transfusion reactions is primarily d ependent on an adequate donor history and meticulous preparation of the don or phlebotomy site. Visual inspection of blood components prior to transfus ion is also vital to preventing these reactions. Several methods of detecti on of bacterial contamination and inactivation of pathogens are currently u nder active investigation. (C) 2001 Editions scientifiques et medicales Els evier SAS.