Kidney transplantation in patients with ANCA-associated vasculitis is associated with a high incidence of post-transplant cancer

Background: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare disease with limited data on outcomes after transplantation. Methods: In this single-center retrospective cohort study, we describe the outcomes of kidney transplant patients with AAV transplanted at our institute from February 2006 to January 2022. Results: We identified 9 patients among 1026 with a pre-transplant diagnosis of AAV; all patients had received previous treatment with cyclophosphamide. Maintenance immunosuppression after transplantation was tacrolimus-based in 89% of the patients. At the end of a mean follow-up of 132 ± 61.1 months after transplantation, only one case of extrarenal vasculitis relapse was observed. The relapse rate was 0.01 per patient per year, which is comparable to that reported in the literature. However, seven patients were diagnosed with cancer after a mean follow-up of 81.4 months after transplantation; six had skin cancer and three had renal cell carcinoma (RCC) of the native kidneys (cumulative incidence of 78%). One patient died from metastatic squamous cell carcinoma. Conclusion: In this study, we found a noticeable decrease in disease relapse (1 relapse in the present cohort vs 7 relapses in 19 patients in the previous cohort) in kidney transplant patients with AAV compared with previous data from our group (December 1987-January 2006). Conversely, we found a high incidence of post-transplant cancer. This result could be attributed to reduced immunosurveillance due to immunosuppression therapy before and after transplantation. Therefore, constant cancer early diagnosis and prevention is mandatory during the post-transplant follow-up of AAV patients.