Regular Article TRANSFUSION MEDICINE Experimental prestorage filtration removes antibodies and decreases lipids in RBC supernatants mitigating TRALI in vivo

• TRALI may be induced by antibodies to HLA or HNA antigens or lipids, which accumulate during storage. • Prestorage experimental filtration of RBCs removes HLA and HNA antibodies, decreases lipid priming activity, and mitigates TRALI in an animal model. Transfusion-related acute lung injury (TRALI) remains a significant cause of transfusionrelated mortality with red cell transfusion. We hypothesize that prestorage filtration may reduceproinflammatory activity in the redblood cell (RBC) supernatant andprevent TRALI. Filters were manufactured for both small volumes and RBC units. Plasma containing antibodies to human lymphocyte antigen (HLA)-A2 or human neutrophil antigen (HNA)-3a was filtered, and immunoglobulins and specific HNA-3a and HLA-2a neutrophil (PMN) priming activity were measured. Antibodies to OX27 were added to plasma, and filtration wasevaluated ina 2-event animalmodel ofTRALI. RBCunits from31donors known tohave antibodies against HLA antigens and from 16 antibody-negative controls were filtered. Furthermore, 4 RBC units were drawn and underwent standard leukoreduction. Immunoglobulins,HLAantibodies,PMNprimingactivity, and theability to induceTRALI inananimal model were measured. Small-volume filtration of plasma removed >96% of IgG, antibodies toHLA-A2andHNA-3a, and their respective primingactivity, aswell asmitigating antibodymediated in vivo TRALI. In RBC units, experimental filtration removed antibodies to HLA antigens and inhibited the accumulation of lipid priming activity and lipid-mediated TRALI. We conclude that filtration removes proinflammatory activity and the ability to induce TRALI fromRBCs andmay represent a TRALI mitigation step. (Blood. 2014;123(22):3488-3495)