Reemerging kidney paired donation in Korea: simultaneous two-way swaps to overcome human leukocyte antigen and anatomic barriers

Background: South Korea first implemented kidney paired donation (KPD) to overcome ABO-incompatible living-donor kidney transplantation. Although utilization declined as desensitization matured, persistent desensitization failure and anatomic constraints have renewed interest in KPD within a regulated framework. We report a recent single-center experience. Methods: KPD exchanges were coordinated within an institutional registry under national supervision. We retrospectively reviewed six consecutive, simultaneous two-way exchanges (12 recipients) from 2022 to 2025. We assessed predefined desensitization failure or anticipated failure with the intended donor, compared immunologic compatibility between intended and exchange donors, and recorded perioperative desensitization, graft function, delayed graft function (DGF), and biopsy-proven acute rejection (BPAR). Results: Five of six exchanges were undertaken for immunologic reasons. All five met criteria for desensitization failure or anticipated failure to the intended donor, with positive crossmatch and high donor-specific antibody (DSA) burden. Reassignment to the exchange donor reduced risk, lowering maximum DSA mean fluorescence intensity (MFI) from 13,228 to 1,350 and total DSA MFI from 20,542 to 2,240, although selective desensitization was still required in some recipients with residual human leukocyte antigen or ABO incompatibility. The remaining exchange addressed an anatomic constraint (adult-pediatric size mismatch). At a median follow-up of 12.2 months (range, 0.9-42.1 months), no DGF or BPAR occurred; all grafts were functioning, and the median estimated glomerular filtration rate was 66.8 mL/min/1.73 m2 . Conclusion: KPD is a safe alternative when desensitization fails or is predicted to fail, including in highly sensitized and anatomically complex candidates. These findings support renewed implementation of KPD alongside selective desensitization in Korea.