Gragert Loren, Kadatz Matthew, Alcorn James, Stewart Darren, Chang Doris, Gill Jagbir, Liwski Robert, Gebel Howard M, Gill John, Lan James H
Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana, USA.
Vancouver Coastal Health Research Institute, Vancouver, Canada.
Am J Transplant. 2022 Dec;22(12):3093-3100. doi: 10.1111/ajt.17175. Epub 2022 Aug 30.
Implementation of the kidney allocation system in 2014 greatly reduced access disparity due to human leukocyte antigen (HLA) sensitization. To address persistent disparity related to candidate ABO blood groups, herein we propose a novel metric termed "ABO-adjusted cPRA," which simultaneously considers the impact of candidate HLA and ABO sensitization on the same scale. An ethnic-weighted ABO-adjusted cPRA value was computed for 190 467 candidates on the kidney waitlist by combining candidate's conventional HLA cPRA with the remaining fraction of HLA-compatible donors that are ABO-incompatible. Consideration of ABO sensitization resulted in higher ABO-adjusted cPRA relative to conventional cPRA by HLA alone, except for AB candidates since they are not ABO-sensitized. Within cPRA Point Group = 99%, 43% of the candidates moved up to ABO-adjusted cPRA Point Group = 100%, though this proportion varied substantially by candidate blood group. Nearly all O and most B candidates would have elevated ABO-adjusted cPRA values above this policy threshold for allocation priority, but relatively few A candidates displayed this shift. Overall, ABO-adjusted cPRA more accurately measures the proportion of immune-compatible donors compared with conventional HLA cPRA, especially for highly sensitized candidates. Implementation of this novel metric could enable the development of allocation policies permitting more ABO-compatible transplants without compromising equity.
2014年肾脏分配系统的实施极大地减少了因人类白细胞抗原（HLA）致敏导致的获取差距。为了解决与候选者ABO血型相关的持续差距，在此我们提出一种新的指标，称为“ABO调整后的cPRA”，它在同一尺度上同时考虑了候选者HLA和ABO致敏的影响。通过将候选者的传统HLA cPRA与ABO不相容的HLA相容供体的剩余比例相结合，为190467名肾脏等待名单上的候选者计算了种族加权的ABO调整后的cPRA值。考虑ABO致敏后，除了AB候选者（因为他们不会发生ABO致敏）外，相对于仅基于HLA的传统cPRA，ABO调整后的cPRA更高。在cPRA点分组=99%的范围内，43%的候选者升至ABO调整后的cPRA点分组=100%，尽管这一比例因候选者血型的不同而有很大差异。几乎所有O型和大多数B型候选者的ABO调整后的cPRA值都会高于这一分配优先级的政策阈值，但只有相对较少的A型候选者出现这种变化。总体而言，与传统的HLA cPRA相比，ABO调整后的cPRA能更准确地衡量免疫相容供体的比例，尤其是对于高度致敏的候选者。实施这一新指标可以制定分配政策，允许进行更多ABO相容的移植，同时又不损害公平性。
