On January 26, 2023, an updated metric for HLA antibody sensitization for the US organ allocation system was released by the United Network for Organ Sharing (UNOS). Under a UNOS contract, our laboratory developed the new reference panel for the calculated panel reactive antibody (CPRA) metric using a dataset of over 2 million high resolution HLA genotypes from the National Marrow Donor Program registry. The CPRA metric is used to determine organ allocation points and priority to ensure equity for highly sensitized transplant candidates who have antibodies against HLA. This updated added the DQA1, DPA1, and DPB1 loci and allowed for allele-specific antibodies to contribute to CPRA. This was the result of an excellent collaboration and data sharing between the stem cell transplant and organ transplant fields.
Please see this page for more information.
Implementation notice: CPRA calculation change
In collaboration with Dr. James Lan at University of British Columbia, we have developed a new metric for immune sensitization that can be applied to improve equity in organ allocation systems, ABO-adjusted calculated panel reactive antibody (cPRA).
Candidates waiting to receive kidneys who have antibodies against HLA are given increased points and priority in organ allocation. Because their pool of compatible donors is smaller, these patients would otherwise not have an equal chance at getting transplanted. The fewer compatible donors, the more points and priority are needed to ensure equity.
Our innovation is applying James’s idea to treat national antibodies against donor ABO blood group in the same way as antibodies against donor HLA.
Patients who are in blood group B and O have decreased access to transplant, and the frequency of B blood group is double in African Americans versus Whites.
Prioritizing transplant candidates with ABO-adjustment combined with policy changes for organ allocation that would allow for more ABO-compatible transplants will expand access and improve equity.
We have developed a web calculator to demonstrate the concept, providing cPRA with and without ABO-adjustment. https://transplanttoolbox.org/abo_hla_cpra/
Please see find our new publication in American Journal of Transplantation.