FP864THE OUTCOME OF KIDNEY TRANSPLANTATION IN ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODY ASSOCIATED VASCULITIS

Abstract

Introduction and Aims: Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) are a group of rare multisystem autoimmune disorders characterised by ANCA positive serology and small vessel inflammation. The main disease subcategories include Granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). AVV often presents as rapidly progressive glomerulonephritis and ESRD is reported to occur in 20-40% of cases. Our aim was to study the outcome of patients with AAV who received a kidney transplant across the East of Scotland, followed by a literature review and a pooled analysis. Methods: All patients who developed ESRD secondary to AAV and received at least one kidney transplant from June 1987 till July 2013 were recruited. This was followed by a detailed review of all the case notes and laboratory reports. Literature search was done using words 'renal transplantation' and 'ANCAvasculitis' in PubMed. Results: 24 patients were included in this analysis with a total of 31 renal transplants. Median follow up was 60.5 months (range 0.5-226) and median age was 51.5 months with majority being female. All patients were ANCA positive at the time of diagnosis with 71% PR3+ and 29% MPO+. Extra-renal involvement included: lung 47%, joints 38%, upper airways 38% and skin 28%. Induction therapy consisted of Cyclophosphamide 94%, plasma exchange 39% and Rituximab in 5%. Maintenance therapy included Azathioprine 88%, Mycophenolic acid 16% and Methotrexate 16%. Pre-transplant relapse occurred in 47% of patients (0.12 relapse/patient-years). Waiting time to transplantation was 32 months (range 3-96). Living donation accounted for 22.5% of transplants. ANCA at the time of transplantation was negative in 63%, positive 23% and borderline 13%. Basiliximab was used in 60% of transplants and the majority had maintenance immunosuppression with Tac/MMF/Pred. Actuarial patient survival at 1 and 5 years were 92% and 87% respectively. Acute rejection occurred in 33% of grafts in the first 2 weeks post-transplantation. Actuarial graft survival at 1 and 5 years were 93% and 56% respectively. The median serum creatinine was 135 μmol/L (range 99-247) at median follow up of 5 years. A total of 6 relapses occurred in 4 patients equating to a relapse rate of 0.004 relapse/patient-years ranging from 7 weeks-15 years post-transplantation. Both allograft and lung involvement was common. Pre-transplantation relapse was not found to be a predictor for relapse post-transplantation (p=0.09). A total of 774 patients receiving 791 kidney transplants (total of 20 studies) were identified in our literature search. Data on ANCA status at the time of transplantation was available in 277 patients with 99 being positive (35.7%). Relapse rate was significantly higher in ANCA positive group (14% vs. 5%, p=0.042). Disease category analysis showed no significant difference in relapse rate with 27 relapses in 188 GPA (14%) vs. 19 relapse in 224 (8%) MPA; p=0.11. Renal relapse occurred in 55% of cases while extra-renal organ involvement occurred in 45%. Graft and patient survival have been reviewed in a number of previous studies and showed mixed results but generally above 60% and 65% at 5 years, respectively. Conclusions: Our single center experience with renal transplantation in AAV shows that renal transplantation remains the best renal replacement therapy in AAV patients with ESRD. Disease relapse post-transplantation is rare and often manifest as extra-renal disease. Finally, multicenter collaboration and large registry data are needed to define predictors of renal outcomes in rare diseases such as AAV.