Introduction:

Similar patient and graft outcomes have been previously reported for ABO compatible (ABOc) and ABO incompatible (ABOi) kidney transplants. However, data are limited on the incidence of CABMR in these groups.

Methods:

This retrospective cohort study included all patients who underwent live-donor kidney transplantation at our center from Nov 2012 to October 2016. Of these, 188 patients were ABOc and 51 were ABOi. Patients with histologic findings of CABMR (Banff '13 criteria) with detectable DSA were identified. Those with CABMR on biopsy without detectable DSA were considered to have suspected AMR. The Kaplan-Meier product limit method was used to compare the time to CABMR (definite+suspected and definite only) between ABOi and ABOc patients.

Results:

The study population was minimally to moderately sensitized, with only 4% and 6% of ABOc and ABOi patients, respectively, having a cPRA≥80%. Over a median follow up of 319 days (IQR: 210-745), seven patients were found to have histologic signs of CABMR. Of these, only two were considered to have definite CABMR (one ABOc; one ABOi). Given the low number of events, there was no clear association between cPRA and CABMR. There was no difference in the actuarial incidence of CABMR between the ABOc and ABOi groups (Fig. 1a; At 3 years: ABOc: 1.1%, ABOi: 2.6%, log-rank p=0.33). When definite + suspected CABMR were considered together, there was a higher incidence among ABOi compared to ABOc patients (Fig. 1a; At 3 years: ABOc: 2.8%; ABOi: 10.9%, log-rank p=0.02). There was no difference in graft or patient survival over 3 years (Fib. 1b).

Conclusion:

CABMR was uncommon following both ABOc and ABOi living donor recipients and patient/graft survival was excellent with follow-up to three years. Our data supports prior data suggesting comparable outcomes between ABOc and ABOi living donor transplants. Further studies are necessary to confirm whether differences in CABMR will become apparent with longer-term follow-up.

CITATION INFORMATION: Sethi S, Vo A, Huang E, Varanasi L, Choi J, Peng A, Najjar R, Jordan S. Chronic Antibody Mediated Rejection (cABMR) in ABO-Incompatible and ABO-Compatible Kidney Transplants: A Single US Center Experience. Am J Transplant. 2017;17 (suppl 3).

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