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Histocompatibility HLA Table Update 2025

eye iconAt a glance

Current Policy

Histocompatibility laboratories see if a transplant candidate and an organ donor are a good match by checking compatibility of proteins found on the surface of cells. These proteins are known as human leukocyte antigens (HLA). The process of identifying one’s HLA genes is called HLA typing.

The OPTN Histocompatibility policies include tables that help match organ donors and transplant candidates based on their HLA types. These tables are used for kidney, pancreas, and kidney-pancreas transplants. Some tables also list unacceptable antigens (UAs), which are HLA types that a patient’s body would likely reject.

Keeping these tables updated helps improve matching and lowers the risk of transplant rejection.

Supporting presentation

View presentation

Proposed changes

  • The OPTN Histocompatibility Committee reviewed these tables and made two updates:

    • Added p-groups, or protein groups, to the DPB1 HLA unacceptable antigen table to allow for more precise typing options

    • Added a specific HLA type, C*04:09L, to the list of unacceptable antigens. This change reflects a recent update in the International Immunogenetics information system, which reclassified this HLA type as having low expression.

Anticipated impact

  • What it's expected to do
    • Help ensure donor typing stays current with the latest science
    • Improve matching and lower the risk of transplant rejection
  • What it won't do
    • This proposal will not affect Calculated Panel Reactive Antibody (CPRA), which is a tool used to figure out how likely it is that a transplant candidate’s body will react badly to organs from most donors. In other words, it helps show how “sensitive” a candidate’s immune system is to donor organs.

Terms to know

  • Alleles: Variations of a gene that can result in different traits in individuals. An individual inherits two alleles for each gene, one from each parent.
  • Calculated Panel Reactive Antibody (CPRA): An algorithm used to determine what proportion of deceased donors a potential candidate may be unable to accept organs from due to immunologic incompatibility.
  • Histocompatibility:The examination of HLA in a patient, often referred to as "tissue typing" or "genetic matching”; tissue typing is routinely performed for all donors and transplant candidates to help match the donor with the most suitable recipients to help decrease the likelihood of rejecting the transplanted organ.
  • Human leukocyte antigen (HLA) system: A group of proteins that help the immune system distinguish the body's own cells from foreign invaders.
  • International Immunogenetics Information System (IMGT): a trusted international resource that collects and organizes information about different versions of human HLA genes.

Click here to search the OPTN glossary

Read the full proposal (PDF)

eye iconComments

Infinite Legacy | 10/01/2025

Infinite Legacy is in support of this proposal and the effort to further detail and refine HLA typing, subsequently reducing the likelihood of transplant rejection. We recognize the positive impact these changes will have on highly sensitized candidates such as women and minority candidates who are more likely to have higher rates of incompatibility due to matching difficulty.

The proposal’s refinements will help transplant programs better assess donor suitability and increase chances for better outcomes, including long-term graft survival. Infinite Legacy urges OPTN to support and provide clear guidance and training on necessary system updates in implementing these refinements.

Region 2 | 10/01/2025

Sentiment: 2 strongly support, 7 support, 3 neutral/abstain, 0 oppose, 0 strongly oppose

Comments: This was not discussed during the meeting, but attendees were able to submit comments with their sentiment. We must remember the science of testing and variability is not complete and individual labs and centers still need to allow for this to continue recipient patient specific virtual crossmatch.

Region 1 | 10/01/2025

Sentiment: 4 strongly support, 4 support, 3 neutral/abstain, 0 oppose, 0 strongly oppose

Comments: This was not discussed during the meeting, but attendees were able to submit comments with their sentiment. An attendee requested that the OPTN should ensure that policy requirements for OPO contract laboratories performing HLA typing of deceased donors clarify whether labs are required to resolve to the P group and null/low expressing allele level and added that NMDP has specific guidance on such alleles that labs are required to resolve in their typing.

Luis Mayen | 10/01/2025

I support these changes as they contribute to more precise and effective organ matching, ultimately benefiting patient outcomes.

Loren Gragert | 10/01/2025

I support with these changes, but there should be a more expansive effort by OPTN to support full WHO HLA nomenclature and enable the capability for all HLA alleles and typing ambiguities to be entered into the allocation system. Currently with the data entered into the OPTN allocation system electronically, as there are all too many cases where there remains uncertainty on compatibility that cannot be resolved without manual inspection during virtual crossmatch of detailed typing data uploaded in PDF format. Many histocompatibility-related offer refusals cannot avoided by HLA labs, and these refusals slow organ placement and may even contribute to nonuse.

The policies Histocompatibility Committee should at the same time stay in alignment with WHO nomenclature rules. Divergence from nomenclature has occurred in some cases, for example the associated antigen DR103 is a split of DR1 in WHO nomenclature, but this no longer true within OPTN Policies. As some transplant programs are utilizing the OPTN Match Run as their final crossmatch (see WTC2025 Abstract# OA25.6), these sorts of divergences introduce risks. The 2022 public comment proposal where this divergence from WHO nomenclature was introduced did not discuss this specific change nor the rationale for it. These changes impact how unacceptable antigens should be entered, and it's possible that not all HLA labs noticed the change in the table since there was no discussion on it. Entering a DR1 unacceptable antigen would block offers of donors with a typing of DR103 before 2022, but not after 2022.

View attachment from Loren Gragert

Region 4 | 10/01/2025

Sentiment: 2 strongly support, 16 support, 5 neutral/abstain, 0 oppose, 0 strongly oppose

Association of Organ Procurement Organizations (AOPO) | 10/01/2025

AOPO appreciates the committee’s completion of the required annual review of the HLA equivalency tables and supports the proposed Histocompatibility HLA Table Update to ensure alignment with the International ImMunoGeneTics (IMGT) database. We commend the committee’s focus and dedication to improving patient safety through continued optimization of typing and reporting practices.

Donor Network West | 09/30/2025

Donor Network West, serving Northern California and Nevada, supports the 2025 Histocompatibility HLA Table Update. Accurate, standardized HLA data are critical for equitable allocation, improved matching, and optimized transplant outcomes. We commend the Committee for aligning the Table with current scientific standards and encourage ongoing review and collaboration with OPOs, transplant centers, and HLA laboratories to ensure effective implementation.

American Society of Transplantation | 09/30/2025

The American Society of Transplantation (AST) supports the proposal, “2025 Histocompatibility HLA Table Update.”

Region 9 | 09/30/2025

Sentiment: 3 strongly support, 2 support, 2 neutral/abstain, 0 oppose, 0 strongly oppose

Comments: This was not discussed during the meeting, but attendees were able to submit comments. A member stated that this is important because it will help HLA lab know how to put unacceptable antigens in the OPTN Computer System.

Lorrinda Gray-Davis | 09/29/2025

Strongly Support

Rebecca Baranoff | 09/29/2025

Strongly Support

American Society for Histocompatibility and Immunogenetics (ASHI) | 09/26/2025

The American Society for Histocompatibility and Immunogenetics (ASHI) and its National Clinical Affairs Committee (NCAC) appreciate the opportunity to provide feedback on this proposal. ASHI supports the proposal for updating the Histocompatibility HLA Table with the addition for DPB1 P groups and C*04:09L to the unacceptable antigen table.

VA Pittsburgh Healthcare System | 09/26/2025

Support

Family Lifestyle Solutions LLC | 09/26/2025

I support the updates in the tables and I appreciate all the hard work that people have done to ensure that the data is complete and provided to the General public. I live in region 10 in the state of Michigan and sometimes I have clients who would like to donate but are afraid, some who are on the list awaiting transplant, those who have their transplant, and sometimes the feedback is not always good. Minority populations are scared that their organs are just being taken for no reason so that others can benefit.

American Nephrology Nurses Association (ANNA) | 09/24/2025

ANNA agrees. We support updates to improve matching and lower the risk of transplant rejection. 

Region 5 | 09/24/2025

Sentiment: 4 strongly support, 14 support, 8 neutral/abstain, 0 oppose, 0 strongly oppose

Comments: This was not discussed during the meeting, but attendees were able to submit comments. One attendee recommended that additional HLA table updates be included. 

Region 10 | 09/24/2025

Sentiment: 5 strongly support, 9 support, 5 neutral/abstain, 0 oppose, 0 strongly oppose

University of Arkansas for Medical Sciences | 09/23/2025

On page 4 of the OPTN document, first paragraph, line 8-there is discussion of the DPB1 epitopes. Our HLA team would like to note that they use these frequently for the virtual crossmatches when dealing with HLA-DPB1 alleles not present in the reagent bead set. Thus, for us, these remain valuable.

Region 6 | 09/19/2025

Sentiment: 2 strongly support, 5 support, 2 neutral/abstain, 0 oppose, 0 strongly oppose

Region 7 | 09/12/2025

Sentiment: 4 strongly support, 9 support, 4 neutral/abstain, 0 oppose, 0 strongly oppose

Comments: None

Region 8 | 09/12/2025

Sentiment: 4 strongly support, 11 support, 3 neutral/abstain, 0 oppose, 0 strongly oppose

Comments: None

Region 11 | 09/11/2025

Sentiment: 3 strongly support, 15 support, 7 neutral/abstain, 0 oppose, 0 strongly oppose

Comments: No comments.

Region 3 | 09/10/2025

Sentiment: 3 strongly support, 6 support, 0 neutral/abstain, 0 oppose, 0 strongly oppose

Pilar Leal | 09/08/2025

Strongly Support

Jullie Hoggan | 08/28/2025

Support updates to improve this system.

Neeraj Sinha | 08/28/2025

This comment is submitted in my personal capacity. I support this infrastructure-building proposal, which establishes the necessary framework for future improvements in organ allocation. I hope that advances in rapid, high-resolution donor typing technology will be made and widely adopted, enabling the full realization of this proposal's benefits.

Terri Milton | 08/27/2025

Support

Anonymous | 08/27/2025

Strongly Support

Anonymous | 08/27/2025

Support