Should the Current Zero HLA ABDR-Mismatch Priority in Kidney Allocation System Continue?: A Critical Appraisal

Area of Science:

• Nephrology
• Transplantation immunology
• Public health policy

Background:

• The Kidney Allocation System (KAS) prioritizes zero Human Leukocyte Antigen (HLA) ABDR-mismatch candidates.
• This priority may disadvantage blood type O candidates due to kidney shunting.
• The study investigates the recipients, donor shunting, and outcomes associated with zero HLA ABDR-mismatch kidney transplants.

Purpose of the Study:

• To identify recipients of zero HLA ABDR-mismatch kidneys.
• To quantify donor shunting to non-identical ABO recipients.
• To assess the impact on pre-transplant dialysis and post-transplant outcomes.

Main Methods:

• Analysis of adult deceased donor kidney transplants from December 4, 2014.
• Exclusion of multi-organ, high CPRA, re-transplant, pediatric, and urgent cases.
• Defined zero-mismatch recipients as those with <98% CPRA receiving a zero HLA ABDR-mismatch kidney.

Main Results:

• Zero HLA ABDR-mismatch recipients were predominantly White, female, with lower CPRAs and less dialysis time.
• 2.46% of blood type O donors were shunted to non-O recipients.
• Zero HLA ABDR-mismatch offered a small graft survival advantage but no patient survival benefit.

Conclusions:

• The zero HLA ABDR-mismatch priority disproportionately affects racial minorities.
• It leads to significant blood type O donor shunting with minimal organ utility improvement.
• Removal of this priority from kidney allocation is recommended.