Preventing hyperacute rejection in a deceased donor kidney transplant recipient

Area of Science:

• Nephrology
• Immunology
• Transplantation

Background:

• Highly sensitized patients face challenges in finding compatible kidney donors.
• Virtual crossmatch (VXM) is a crucial step in pre-transplant compatibility assessment.
• Unexpected positive physical crossmatch (PXM) results can delay or prevent transplantation.

Purpose of the Study:

• To investigate the cause of a discrepant T/B physical crossmatch (PXM) in a highly sensitized kidney transplant recipient.
• To identify the source of error in donor human leukocyte antigen (HLA) typing.
• To ensure accurate compatibility assessment for deceased donor kidney offers.

Main Methods:

• Conducted a thorough investigation of a positive PXM despite a negative VXM.
• Ruled out technical errors such as prozone effect, sample swaps, and new sensitization.
• Re-evaluated donor HLA typing and considered donor ethnicity to identify potential discrepancies.

Main Results:

• Initial VXM indicated compatibility, but PXM was unexpectedly positive.
• Investigation ruled out common causes of false positive PXM results.
• Discrepancies in Donor 1's HLA typing were identified, linked to ethnicity and HLA linkage disequilibrium.
• Corrected HLA typing revealed strong donor-specific antibodies (DSA), explaining the positive PXM.

Conclusions:

• Inaccurate donor HLA typing can lead to critical discrepancies between VXM and PXM.
• Donor ethnicity and HLA linkage disequilibrium are important considerations in HLA typing accuracy.
• Thorough investigation of crossmatch discrepancies is vital for successful kidney transplantation in highly sensitized patients.