High Transplant Rates of Highly-Sensitized Recipients with Virtual Crossmatching in Kidney Paired Donation: 722

Introduction: In kidney paired donation (KPD) flexibility in the allocation of incompatible pairs is required if a critical mass of pairs to efficiently find matches can't be reached. Methods: The first year experience of the Australian program was reviewed with respect of matched and transplanted recipients. Matching was based on acceptable mismatches, with donors excluded from matching to recipients with Luminex donor-specific antibodies (DSA) >2000MFI. Results: Four quarterly match runs were performed, which included 53 pairs and 2 altruistic donors. HLA incompatibility accounted for 90% of the listed pairs. In run 2 only the DSA threshold was increased to >8000MFI and optional ABO incompatible matching was introduced from run 4. Matches were identified in 37 (70%) patients, of whom 92% had a negative crossmatch with their matched donor. Crossmatch positive results were found only in recipients with DSA>2000MFI. In 4 cases immunological reasons and in 4 cases other reasons resulted in breakdown of chains and 17 patients not progressing to transplantation. Eventually, 20 (38%) patients received a KPD transplant and 35% of these had a calculated PRA >90%. Conclusion: KPD is a valid and effective solution for patients with immunologically incompatible donors even in the context of highly sensitized recipients.