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Update Human Leukocyte Antigen (HLA) Equivalency Tables

eye iconAt a glance

Current policy

Histocompatibility laboratories test compatibility of transplant candidate and organ donor tissues using the human leukocyte antigen (HLA) system. This process is also known as HLA typing. When a candidate is more compatible with the donor, there is less risk the candidate’s body will reject the transplant.

The laboratories use commercially available kits to do the tests. The antigens used in the testing are included in tables in OPTN policy and programmed into the OPTN computer system. 

The antigens in the tables are reviewed and updated every year to make sure they include the most up-to-date information. 

In addition, some HLA reporting is not required for deceased donors, but is entered for transplant candidates. Requiring the HLA to be reported for both the donor and transplant candidate would make matching donors with transplant candidates more accurate.

Supporting media

Presentation

View presentation

Proposed changes

  • Updates to existing HLA reference tables in OPTN Policy 4.10: Reference Tables of HLA Antigen Values and Split Equivalences
  • Add new reference table to be programmed into the OPTN computer systems
  • Add a requirement for HLA typing on deceased donors to be reported in the OPTN computer system

Anticipated impact

  • What it's expected to do
    • Align data collection for deceased donors and transplant candidates
    • More accurately prioritize transplant candidates whose immune system makes it more likely they will reject organs from a large percentage of organ donors
  • What it won't do
    • Change the Calculated Panel Reactive Antibodies (CPRA) calculation or frequency data used for the calculation

Themes

  • Patient Safety

Terms to know

  • Calculated Panel Reactive Antibody (CPRA): An algorithm used to determine what proportion of deceased donors a potential candidate may be unable to accept 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 helps the immune system distinguish the body's own cells from foreign invaders.
  • UNetSM: Computer system used to house all donor information, transplant patient information and data reports needed to evaluate the nation’s organ donation and transplant system.

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eye iconComments

Region 11 | 09/30/2021

Region 11 sentiment: 9 strongly support, 7 support, 2 neutral/abstain, 0 oppose, 0 strongly oppose Region 11 supported the proposal with no comments.

NATCO | 09/29/2021

NATCO supports the proposed changes to update the HLA reference tables including the addition of a new reference table programmed into the OPTN computer system to ensure the most up-to-date information. Additionally, NATCO supports the proposed requirement for OPOs to report HLA typing for donors in an effort to improve transplant patient safety.

American Society of Transplant Surgeons | 09/29/2021

The American Society of Transplant Surgeons (ASTS) supports the OPTN proposal to require DPA typing and other items in the proposal for the following reasons. 1) It will improve safety (and presumably outcomes) in that unacceptable antigens can be assigned for DPA, depending on the center. 2) Over time, this will allow the use of DP loci to refine the CPRA calculator (recipients with DQA and DPA antibodies don’t get the benefit of the CPRA points). 3) It is not a major burden on HLA labs since most of them are doing it already and there is no technological barrier to implementing it.

Attachment

American Society of Transplantation | 09/29/2021

The American Society of Transplantation supports this proposal as written. Updating antigens in the tables is important from a patient safety standpoint. Highly sensitized patients may develop antibodies against HLA-DPA1, and the typing of HLA-DPA1 will improve the safety and accuracy of virtual crossmatch results. In addition, most labs already perform HLA-DPA1 typing for deceased donors, so this change will not add a significant burden to HLA laboratories, OPOs or Transplant programs.

ASHI | 09/28/2021

The American Society for Histocompatibility (ASHI) and its National Clinical Affairs Committee (NCAC) appreciate the opportunity to comment on the proposal of updating the HLA Equivalency Tables. ASHI strongly supports the requirement of DPA1 typing for deceased donors and kidney paired donation living donors, and the incorporation of DPA1 unacceptable antigen reporting mechanism and equivalency to the matching system. ASHI appreciates that the UNOS Histocompatibility Committee has carefully evaluated and taken into consideration the addition of DQA1, DPA1 and DPB1 to the calculation of CPRA based on the unacceptable antigen assignment of these loci. ASHI believes that the addition of donor DPA1 typing, the reporting of DPA1 as unacceptable antigen for transplant candidates, and ultimately the inclusion of all HLA loci in the calculation of recipients’ CPRA align with the overall OPTN strategic goals. 1. ensuring equity in access to transplants, particularly for the highly sensitized candidates who are biologically disadvantaged due to their difficult-to-match status 2. promoting transplant recipient safety 3. improving transplant outcomes. In addition, ASHI supports the removal of broad antigen equivalents to allelic antibodies as indicated in Figure 2. ASHI also supports the updates to the DPB1 equivalencies and reporting values as indicated. The proposed updates are necessary in order to accurately assess the immunologic risk of the patient and are appropriate given the advancement of HLA testing systems and the increasing number of HLA alleles. Finally, ASHI supports the alignment of HLA data collection within all UNet systems to ensure the consistency and smooth data transfer of all HLA-related values across different entities.

Malek Kamoun | 09/28/2021

I strongly support the requirement of DPA1 typing for deceased donors and kidney paired donation living donors, and the incorporation of DPA1 unacceptable antigen reporting mechanism and equivalency to the matching system. The addition of donor DPA1 typing, the reporting of DPA1 as unacceptable antigen for transplant candidates, and ultimately the inclusion of all classical HLA loci in the calculation of recipients’ CPRA align with the overall OPTN strategic goals: a) ensuring equity in access to transplants, particularly for the highly sensitized candidates who are biologically disadvantaged due to their difficult-to-match status; b) promoting transplant recipient safety; and c) improving transplant outcomes. In addition, I also support the following changes: a) removal of broad antigen equivalents to allelic antibodies; b) the updates to the DPB1 equivalencies and reporting values; the proposed updates are appropriate given the advancement of HLA testing systems and the increasing number of HLA alleles; and c) the alignment of HLA data collection within all UNet systems to ensure the consistency and smooth data transfer of all HLA-related values across different entities.

Region 10 | 09/28/2021

Region 10 sentiment: 8 Strongly Support; 12 Support; 0 Neutral/Abstain; 0 Oppose; 0 Strongly Oppose Comments: None

Region 1 | 09/24/2021

Region 1 sentiment: 2 Strongly Support, 6 Support, 0 Neutral/Abstain, 0 Oppose, 0 Strongly Oppose. No comments.

American Nephrology Nurses Association (ANNA | 09/23/2021

ANNA supports

Attachment

Region 6 | 09/23/2021

Region 6 sentiment: 4 Strongly Support; 5 Support; 1 Neutral/Abstain; 0 Oppose; 0 Strongly Oppose. No comments.

Region 8 | 09/22/2021

Region 8 sentiment: 9 strongly support, 9 support, 5 neutral/abstain, 0 oppose, 0 strongly oppose. Comments: Region 8 supports this proposal.

Region 7 | 09/15/2021

Region 7 sentiment: 5 strongly support, 9 support, 3 neutral/abstain, 0 oppose, 0 strongly oppose. No comments.

Region 9 | 09/15/2021

Region 9 sentiment:  2 Strongly Support; 4 Support; 3 Neutral/Abstain; 0 Oppose; 0 Strongly Oppose. No comments .

Linda Cagle | 09/14/2021

Would like to see the CPRA algorithm updated to include HLA-DQA1, DPA1, DPB1 unacceptable antigens to improve organ matching/allocation. Transplant candidates with only antibodies to HLA-DQA1, -DPA1 and -DPB1 are at a disadvantage when they are (highly) sensitized; however, their CPRA does not currently reflect their actual HLA antibody profile.

Region 3 | 09/10/2021

Region 3 sentiment: 4 strongly support, 9 support, 2 neutral/abstain, 0 oppose, 0 strongly oppose

Region 2 | 09/10/2021

• Region 2 sentiment: 8 Strongly Support, 15 Support, 4 Neutral/Abstain, 0 Oppose, 0 Strongly Oppose • Comments: This was not discussed during the meeting but OPTN representatives were able to submit comments with their sentiment. The region supported the proposal, but one member noted that there should be more impetus in CLASS II matching especially DQ and EPLET matching in pediatric transplant recipients. Another member expressed disappointment that the proposal does not change the Calculated Panel Reactive Antibodies (CPRA) calculation. The member noted that the committee should address this in the near future.

Region 5 | 08/30/2021

Region 5 sentiment: 7 strongly support, 15 support, 5 neutral/abstain, 0 oppose, 0 strongly oppose. Region 5 supported the proposal for the Update to HLA Equivalency Tables.

Region 4 | 08/27/2021

3 strongly support, 6 support, 2 neutral/abstain, 0 oppose, 0 strongly oppose. Region 4 supported this proposal.