Characteristics and clinical application of blood filters

Microaggregate blood filters (MAFs) may be beneficial for patients at increased risk of ARDS receiving massive transfusion, although their use is not uniformly recommended. While new leukocyte adsorption filters (LAFs) are more efficient for white cell removal, both MAFs and LAFs successfully reduce the incidence of febrile reactions to red cell components by reducing the residual leukocyte content below 109. It is likely that leukocyte removal delays or prevents recipient HLA alloimmunization from transfusion. LAFs offer a simple means of providing both red cells and platelets, depleted of leukocytes to levels below 108 and may prevent or delay the onset of HLA alloimmunization. A promising area of application of LAFs is for prevention of transfusion-transmitted CMV where leukocyte-depleted components may be noninfectious. Several secondary benefits of leukocyte-depleted components are anticipated, including a decreased risk of HTLV-1 transmission, reduced degree of transfusion-mediated immunosuppression and a lowered risk of graft-vs-host disease.