OR11 Characteristics of transplant candidates with cPRA ⩾ 99.95% likely to be allocated organs from deceased donors

Abstract

Aim Since the new KAS, candidates with cPRA = 100% were prioritized for deceased donor (DD) kidneys, their transplant rates increased from 2.7% to as high as 19.1%. A recent simulation (CJSAN 11:505-511, 2016), predicted that not all cPRA=100% are equally advantaged. While ∼ 75% cPRA =100% candidates were compatible with an average of 17 donors (total donors = 6141), ∼ 25% were incompatible with every donor and related to cPRA values of 99.45–>99.99% being ”rounded up” to 100%. Indeed, 91% of candidates without a compatible donor had cPRA values >99.9%. Subsequent data with actual transplants (AJT 16:1834-1847, 2016) supported those predictions. In our program, 61 cPRA = 100% candidates were transplanted from 12/04/14-01/12/18. Surprisingly, 15 recipients had cPRA values ⩾99.95%. In this study, we identified their characteristics. Methods HLA profiles and demographic information from 15 cPRA ⩾99.95% recipients were compared to 30 non-transplanted case controls with cPRA ⩾99.95%. The HLA typing data of each subject was entered into Haplostats (haplostat.org) and the top ranked phased haplotypes for each were recorded. Results Among cPRA⩾99.95% recipients, 11/15 (73%) had one or both of their HLA haplotypes ranked among the top 125 CAU haplotypes. CAU haplotypes were the focus as CAU represent ∼ 67% of kidney donors. Notably, 7/15 recipients had one or both of their HLA haplotypes among the top four ranked CAU haplotypes and 6/15 received transplants from homozygous donors. Among recipients, eight were AA (53%), six were CAU and one was HIS. In contrast, among 30 case controls, 4 (13.3%) had one haplotype ranked in the top 125 and 17 had one haplotype ranked in the top 8000. For 9 candidates, neither HLA haplotype was ranked among the top 10,000 CAU haplotypes. Importantly, 25/30 (83.3%) controls were African American. Conclusions Kidney transplant candidates with cPRA⩾99.95% were more likely to be transplanted when at least one of their HLA haplotypes was frequent (rank ⩽ 125). This novel observation offers an opportunity to medically optimize a subset of highly sensitized candidates before deceased donor transplantation. It also suggests amendments may be necessary to minimize racial disparity in the KAS. Additionally, alternative approaches should be considered for candidates not likely to receive a DD offer. H.M. Gebel: 2. Consultant; Company/Organization; Astellas, Thermofisher.