[Leucocyte removal and its clinical application]

Blood transfusion leads to leucocyte-mediated adverse reactions related to the transfusion of leucocytes in allogeneic blood and blood products. The leucocytes are also capable of transmitting virus infection. Leucocyte depletion of homologous blood products can effectively reduce the immunosuppressive effect as well as minimize the likelihood of transmitting virus. Blood component transfusion is generally "buffy-coat-poor", which removes about two thirds of the leucocytes present in whole blood. Using special filters, blood component can be filtrated 99.9% of the leucocytes. Leucocyte-depletion using filter should significantly lessen the leucocyte-mediated transfusion adverse reactions, such as febrile non-hemolytic transfusion reactions and graft versus host disease. At the same time, leucocyte filtration can decrease the risk of transmitting virus. Otherwise, leucocyte-depletion plays very important role in the treatment of cardiac surgical patients to attenuate leukocyte-mediated inflammation and organ reperfusion injury, the treatment of ulcerative colitis, and the treatment intractable diseases such as autoimmune and neurologic diseases.