#6797 EFFICACY OF DESENSITIZATION TREATMENT IN HYPERIMMUNIZED PATIENTS AWAITING A CADAVERIC KIDNEY TRANSPLANTATION

Abstract

Abstract Background and Aims On all kidney waiting lists, patients who have antibodies against more than 80% of a panel reactive antibody (PRA) are difficult to transplant, even with national or regional programs. Desensitization treatment with high-dose intravenous immunoglobulin and rituximab could be offered to patients with a long waiting time for a cadaveric donor to improve their odds of finding a kidney. Method Retrospective, single-center study including all hyperimmunized patients on the waiting list for a cadaveric kidney donor who received a desensitization treatment between 2010-2020. To be considered to the desensitization protocol, all the patients must have a PRA above 75% and have been on the waiting list more than 3 years, without any offer. Our treatment was based on the modified Cedars-Sinai Medical Center protocol. Eight hyperimmunized patients on the waiting list for a cadaveric donor kidney transplant (50% male with a mean age of 41.5±16.4 years) received desensitization treatment with intravenous immunoglobulin and Rituximab. Six of the 8 patients (75%) were on renal replacement therapy with hemodialysis and two on peritoneal dialysis (mean time on dialysis 48±14 months). 75% had received a previous transplant. The median PRA calculated was 98%. The time between desensitization and kidney transplantation, the percentage of reactivity against panel cells (PRA) before and after therapy, graft and donor survival, as well as episodes of acute rejection and viral infections were analyzed. The mean follow-up time after transplantation was 67 months. Results No patient presented significant side effects to desensitization treatment. Seven of the 8 patients (87.5%) could be transplanted from a cadaveric donor (negative crossmatch test), in a median 8 months after desensitization. No significant changes were observed in the PRA levels. In the immediate post-transplant period, there were 2 graft losses (28.6%) due to non-immunological causes (1 venous thrombosis in a patient with a coagulation disorder and 1 primary graft failure). Creatinine at discharge was 1.6±0.4 mg/dl and 1.4±0.2 a year after the transplant. Five-year censored death graft survival was 100%. Three patients presented viral replication (1 due to cytomegalovirus (CMV), 1 due to polyomavirus (BK) and another CMV+BK), which became negative after switching to m-Tor therapy. There were no episodes of acute rejection. No patient developed cancer during the follow-up. Conclusion Desensitization treatment with immunoglobulin and rituximab on hyperimmunized patients on the cadaveric waiting list is a safe and effective treatment that increases the chances of achieving a kidney transplant in highly sensitized patients.