Acute Rejection and Relapse of Native Disease in Kidney Transplant Recipients with ESKD from ANCA-Associated Vasculitis: Insights from a Single-Center Study

Background: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare systemic autoimmune disease characterized by necrotizing inflammation of small blood vessels leading to end-organ damage. Up to 40% of AAV patients progress to end-stage kidney disease (ESKD), necessitating renal replacement therapy. The long-term outcomes of patients with AAV after renal transplantation are not well described. Our study aims to evaluate biopsy proven acute rejection (BPAR) and relapse of AAV following transplantation at our center. Methods: We retrospectively reviewed all patients with ESKD secondary to AAV who underwent a kidney transplant at the University of Iowa between January 2000 and October 2023. 33 kidney transplants were completed in 30 patients. Results: Among the 33 transplant episodes, 18 grafts were from deceased donors, 3 from living unrelated donors, and 12 from living related donors, including an identical twin. 3 patients (9%) developed AAV relapse between 4 and 117 months after transplantation and, all had p-ANCA sub-type of AAV. None required dialysis or lost their graft. 9 patients (27%) developed BPAR between 2 and 178 months after transplant. Of these, 5 had p-ANCA, 2 c-ANCA, and 2 had unknown sub-types. 5 of the 9 developed graft failure requiring dialysis (15%). 3 patients died with functioning graft, 1 after rejection treatment, 1 after relapse of AAV and one of non AAV disease (42, 92 and 120 months after transplant). Conclusion: Our data indicates transplant and overall survival rates in patients with ESKD secondary to AAV are comparable to those receiving kidney transplants for ESKD due to other causes. AAV relapse after kidney transplantation is uncommon but appeared exclusively in patients with the p-ANCA subtype and those who received IL-2RA or no induction. Kidney transplantation remains a viable and effective treatment option for these patients and larger database analysis are necessary to better characterize those at risk for disease relapse and BPAR.