Time to Move on: HLA Matching Should Be Reconsidered in Modern Deceased Donor Kidney Allocation

Area of Science:

• Nephrology
• Transplantation immunology
• Public health

Background:

• Human Leukocyte Antigen (HLA) matching is a key factor in deceased donor kidney allocation, aiming to improve transplant success.
• However, HLA matching policies can inadvertently create racial inequities, prompting consideration of non-allogenic factors like recipient age.

Purpose of the Study:

• To evaluate long-term graft and patient outcomes in deceased donor kidney transplantation based on HLA-matched versus non-matched allocation cohorts.
• To investigate the influence of reduced dialysis time on the observed benefits of HLA matching.

Main Methods:

• Analysis of 7440 adult deceased donor kidney transplants from the Australia and New Zealand Dialysis and Transplant Registry (2000-2018).
• Classification of transplants as HLA matched or nonmatched using the OrganMatch score and local allocation algorithms.
• Statistical analysis included linear mixed modeling for graft function, logistic/binomial regression for rejection, and Kaplan-Meier/Cox regression for graft failure and survival.

Main Results:

• Forty percent of transplants were HLA matched, showing significantly higher mean glomerular filtration rates.
• HLA-matched transplants demonstrated longer graft survival (15.9 vs. 12.7 years) and improved recipient survival (HR 0.83).
• Matched recipients spent less time on dialysis (28.1 vs. 44.8 months), a factor contributing to better graft and survival outcomes; Caucasian recipients were more likely to receive matched transplants.

Conclusions:

• While HLA-matched kidney transplants offer benefits in graft and recipient outcomes, some advantages appear linked to reduced dialysis duration.
• The advantages of HLA matching for some recipients came at the cost of longer dialysis times for non-matched recipients, disproportionately affecting minority racial groups.
• The study highlights the complex interplay between HLA matching, dialysis duration, and potential racial disparities in kidney allocation.