Introduction. It is now appreciated that greater HLA DR mismatching of the first pediatric kidney transplantation is associated with higher degrees of sensitization, lower rates of retransplantation, longer time to retransplantation and worse graft outcomes in those who are subsequently retransplanted (Transplantation 2013; 95:1218). In view of those and other data our pediatric renal transplant program has preferentially used only 0 and 1 HLA DR mismatched kidneys, while consideration for 2 DR mismatched kidneys is reserved for patients whose sensitization levels and/or course on dialysis mandates an imminent need for a kidney. An appealing new paradigm is an HLA DR and DQ epitope matching strategy that can ideally minimize de novo donor specific antibody (dnDSA) production to DR and DQ antigens when < 10 DR and < 17 DQ eplet mismatches are present in the donor (AJT 2013; 13:3114). We evaluated the role of DR and DQ eplet mismatching of deceased donor (dd) offers made to our pediatric wait list candidates.

Methods. We evaluated 79 offers that were made to 16 children on our UNOS waiting list from 27 consecutive dd from 4/14/14 to 3/23/15. Each donor/candidate pair was HLA DR (ß1, ß3 and/or ß5) and DQ (α1 & ß1) allele typed by rSSO and were then evaluated by the HLA matchmaker program for eplet mismatches.

Results. The data in Table 1 show that 90.5% (19/21) of the 1 DR mismatched dd offers were above both the DR and DQ eplet thresholds making those candidates at high risk for dnDSA production. Furthermore, for 2 DR mismatched offers, 96.7% (56/58) of the candidates' offers had both a DR and DQ eplet threshold levels above 10 and 17, respectively.

Conclusions. Compared to DR matching, eplet mismatching more accurately defines the molecular difference between a donor and candidate but the fact that less than 10% of the offers existed where both the DR and DQ eplet threshold was in the low risk threshold may preclude strategies designed to optimize matching and access to dd organs.

CITATION INFORMATION: Bryan C, Chadha V, Warady B. Should HLA DR and DQ Eplet Mismatching Replace Traditional DR and DQ Mismatching for Deceased Donor Offers in Pediatric Renal Transplantation? Am J Transplant. 2016;16 (suppl 3).

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