Long-term Graft and Patient Survival in Kidney Transplant Recipients With High Levels of Preformed DSAs (MFI > 3000): A Propensity Score-matched Analysis.

Background: Kidney transplant recipients with preformed donor-specific antibodies (DSAs) are at higher risk for antibody-mediated rejection (AMR) and graft failure. This study assesses outcomes during a 15-y period, comparing patients with high levels of preformed DSAs to a matched cohort of recipients without DSA. Methods: This retrospective study includes 95 patients with high levels of preformed DSAs, defined by DSA levels (mean fluorescence intensity > 3000). Using propensity score matching, 88 of these patients were matched to 154 recipients without DSA based on age, sex, transplant year, cold ischemia time, and other clinical factors. Outcomes included occurrence of AMR, T cell-mediated rejection, and long-term allograft and patient survival. Results: The mean follow-up after transplantation was 11.9 ± 5.6 y. Among the matched patients, kidney allograft survival rates after transplantation at 5, 10, and 15 y were 90.5%, 79.5%, and 72.8% for the patients without preformed DSA and 86.7%, 60.2%, and 47.6% for the patients with high levels of preformed DSAs (P = 0.002). The patient survival rates after transplantation at 5, 10, and 15 y were 91.3%, 72.3%, and 57.9% for the patients without preformed DSA and 86.4%, 71.2%, and 49.0% for the patients with high levels of preformed DSAs (P = 0.206). More AMR occurred in the patients with high levels of preformed DSAs (P < 0.001) without significant difference in T cell-mediated rejection (P = 0.203). Conclusions: Although patients with high levels of preformed DSAs have a higher risk of graft loss, their long-term survival did not differ significantly from recipients without DSA, supporting the use of intensive immunosuppression in this population.