Histocompatibility HLA Table Update 2025

At 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)