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Units of whole blood, red blood cells, and platelets contain significant numbers of leukocytes while fresh frozen plasma and cryoprecipitate do not. Transfusion of leukocytes has been associated with several adverse sequelae, including:
Leukocytes can be removed immediately after collection or at the bedside using third generation adsorption filters that remove 99.9% of leukocytes. Pre-storage leukoreduction has the additional advantages of preventing cytokine release from white blood cells during storage and elimination of the need for bedside filters that have slower flow rates than standard blood filters. Prestorage leukocyte reduction has also been proven to more consistently remove enough white blood cells to meet the definition of a leukocyte reduced unit. If bedside leukoreduction is necessary, one unit of red blood cells can be transfused through a single filter. A pool of 8-10 random donor platelet concentrates can be transfused through a single platelet filter. On September 18, 1998, the Blood Products Advisory Committee of the FDA recommended universal leukoreduction of all cellular blood components, except granulocytes. Many other countries already required universal leukoreduction of blood components. On September 28, 1998, the Transfusion Committee at Saint Luke's Hospital in Kansas City decided that all patients at Saint Luke's Hospital should receive leukoreduced red blood cells and platelets. The hospital transfusion service implemented the new policy on November 1. Leukocyte reduced components are more expensive. However, the Biological Practices Committee stated that the clinical benefits far exceed the increase in blood component cost. The advantages of leukocyte removal include decreased risk of:
Established Indications: Prevention of febrile reactions following two documented febrile reactions Febrile reaction and demonstrable WBC antibodies Prevention of transfusion related acute lung injury Prevention of HLA alloimmunization in multi-transfused patients including:
Heart transplant recipients Substitute for CMV negative components, when none are available HIV infected patients Antepartum transfusions for CMV negative women The most common indication for using leukocyte reduced blood components is the prevention of febrile transfusion reactions. TRALI is most often caused by the passive transfusion of a blood component containing high-titer anti-HLA antibodies, which react with the recipient's leukocytes (80-90%). However, it may also be caused by anti-HLA antibodies in the recipient's plasma reacting with leukocytes in transfused units of whole blood, red blood cells, or platelets (10-20%). Transfusing leukocyte reduced blood components to such recipients requiring subsequent transfusions can prevent TRALI caused by this second mechanism. Leukocyte reduction will not prevent acute lung injury resulting from high titers of HLA antibodies in the donor unit. Leukocyte reduced components may also delay or prevent alloimmunization to HLA and leukocyte-specific antigens in chronically transfused patients and, thereby, delay the onset of refractoriness to random donor platelet transfusions. Patients expected to receive only a few blood components, such as during elective surgery, do not derive much benefit from the additional expense. Some viruses such as CMV reside in granulocytes. Pre-storage leukocyte reduction eliminates the risk of CMV transmission. Leukocyte reduction has convincingly been shown to reduce the incidence of CMV seroconversion in CMV negative leukemia patients treated with chemotherapy and bone marrow transplantation. Leukocyte removal filtration can be used in the following clinical situations when CMV negative components are not available: Indications for Substituting Leukocyte Reduced for CMV Negative Blood
Administration of pre-storage leukoreduced RBCs and platelets is the same as regular units. The use of bedside leukoreduction filters may significantly slow flow rates, which precludes their use in emergent situations where multiple rapid transfusions are required. External pressure devices should not be used, because they reduce the efficiency of leukocyte removal. |
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