A2/A2B to B deceased donor kidney transplantation in the Kidney Allocation System era
Shivani Bisen, Laura B. Zeiser, Samantha Getsin, Teresa Po‐Yu Chiang, Darren Stewart, Kayleigh Herrick‐Reynolds, Sile Yu, Niraj M. Desai, Fawaz Al Ammary, Kyle R. Jackson, Dorry L. Segev, Bonnie E. Lonze, Allan B. Massie
Abstract
Kidney transplantation from blood type A2/A2B donors to type B recipients (A2→B) has increased dramatically under the current Kidney Allocation System (KAS). Among living donor transplant recipients, A2-incompatible transplants are associated with an increased risk of all-cause and death-censored graft failure. In light of this, we used data from the Scientific Registry of Transplant Recipients from December 2014 until June 2022 to evaluate the association between A2→B listing and time to deceased donor kidney transplantation (DDKT) and post-DDKT outcomes for A2→B recipients. Among 53 409 type B waitlist registrants, only 12.6% were listed as eligible to accept A2→B offers ("A2-eligible"). The rates of DDKT at 1-, 3-, and 5-years were 32.1%, 61.4%, and 72.1% among A2-eligible candidates and 14.1%, 29.9%, and 44.1% among A2-ineligible candidates, with the former experiencing a 133% higher rate of DDKT (Cox weighted hazard ratio (wHR) = 2.19 2.33 2.47 ; P < .001). The 7-year adjusted mortality was comparable between A2→B and B-ABOc (type B/O donors to B recipients) recipients (wHR 0.78 0.94 1.13 , P = .5). Moreover, there was no difference between A2→B vs B-ABOc DDKT recipients with regards to death-censored graft failure (wHR 0.77 1.00 1.29 , P > .9) or all-cause graft loss (wHR 0.82 0.96 1.12 , P = .6). Following its broader adoption since the implementation of the kidney allocation system, A2→B DDKT appears to be a safe and effective transplant modality for eligible candidates. As such, A2→B listing for eligible type B candidates should be expanded.