P088 Effect of leukoreduction of transfused blood products on deceased donor hla typing

Abstract

Aim Deceased donor HLA typing is predicated on the assumption that the blood sample contains only DNA from the organ donor. Prior to procurement, most organ donors receive at least one unit of red blood cells (RBC), with some receiving >20, as part of life support or in order to maintain organ viability. Non-organ donor DNA acquired from transfusion may result in incorrect and/or ambiguous HLA typing, which could have dire consequences for the organ recipient. We investigated the impact of RBC transfusion on HLA typing with leukoreduced (LR) and non-LR RBCs. Methods To replicate the average total blood volume (TBV) of 5L, an in vitro model of 5 mL was used. Varying volumes of LR and non-LR donor RBCs (e.g. 0.25 mL in vitro = 1 RBC unit in vivo) were mixed to simulate different transfusion scenarios (Table). Typing was performed by real time PCR using Linkage Biosciences HLA typing kit (11 loci+: HLA - ABCDRDQDP SABR™ 384 Kits) and software (SureTyper™). Results For non-LR scenarios of 10 and 2 RBC units, PCR was unable to assign a definitive HLA type (i.e.“no call”) for multiple loci as >2 antigens per locus were detected. In the 1 non-LR RBC scenario, some loci had donor-specific positive wells that if ignored resulted in recipient typing. In contrast, both the 16 and 19 LR-RBC transfusion scenarios, which approach replacement of TBV, resulted in non-ambiguous recipient typing. Even when DNA concentration was low (3 ng/μl), recipient typing was assigned despite well drop-outs. Conclusions Our results show that HLA typing for deceased donors is differentially impacted by RBC LR status. Whereas non-LR RBCs can result in ambiguous or incorrect recipient typing, LR RBCs do not appear to preclude definitive typing results. Given that approximately half of the U.S. blood supply is non-LR, determining LR status has testing and clinical implications. If LR RBCs are given, regardless the volume, HLA typing should not be affected and there is no reason to delay typing for additional DNA material (e.g. lymph node, pre-transfusion sample). Download : Download high-res image (262KB) Download : Download full-size image