Preventing hyperacute rejection in a deceased donor kidney transplant recipient.

A 36-year-old, highly sensitized (cPRA 99.99 %) male listed for his third kidney transplant for more than 12 years received a deceased donor offer. The virtual crossmatch (VXM) indicated that the patient had two weak donor-specific antibodies (DSA) to DR10 and DP17 against potential Donor 1, which would correlate with a negative T/B physical crossmatch (PXM). However, the PXM results were unexpectedly positive over 300 median channel shifts (MCS). Investigation into the discrepancy ruled out new sensitization and prozone effect. Repeated PXM showed results consistent with the initial findings and ruled out a sample swap of the donor cells or patient serum.Conditions such as auto-immune diseases and HIV, which could cause false positive PXM were also ruled out. Coincidentally, the patient received a second deceased donor offer (Donor 2) with identical HLA typing to Donor 1 from the same Organ Procurement Organization (OPO) on the same day. Further investigation of the ethnicity of the two donors revealed that Donor 1 was of African American (AFA) origin, and Donor 2 was Caucasian (CAU). Based on HLA disequilibrium, it is highly impossible that the two donors would share the same HLA typing, as A30-B42-DR18-DQ4 is the most common haplotype in AFA, and nearly absent in CAU populations. Repeating HLA typing of Donor 1 showed discrepant results from the initial HLA typing provided by the OPO. The updated VXM with the correct typing for Donor 1 revealed strong DSA to A1, A33, Cw8, DQ7, and DQA1*05, which corresponded with the PXM result.