Background:Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) include granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EPGA). Renal involvement is frequent in AAV and is an important factor for morbidity and mortality.Objectives:The main objective of this study was to analyze the demographic, clinical, histological and therapeutic characteristics of renal involvement in patients with AAV and the risk of renal replacement therapy (RRT) or death.Methods:Retrospective observational study of 56 patients with AAV fulfilling classificatory criteria and renal involvement diagnosed between 1995 and 2020 from a Spanish tertiary centre. We studied the histological involvement (according to the 2010 classification in focal, crescentic, mixed or sclerotic), immunofluorescence (IF) and the treatment received with the risk of RRT or death.Results:We included 56 patients diagnosed with AAV and renal involvement. The mean age was 61.08±4.05 years; 58.9% were women. The mean follow-up time of these patients was 16.14± 8.80 years. Only 57.1% of patients presented systemic involvement.Most frequent non-renal AAV manifestations were lung involvement (39.3%), central nervous system (30.4%), otorhinolaryngology (ORL) (14.3%), skin (8.9%) and cardiac involvement (8.9%). Main immunological findings were ANCA-MPO+ (69.6%), ANCA-PR3+ (23.2%), ANCA-negative (5.4%). Low C3 was found in 19.6% patients. Histologic classification (HC) and need of RRT is described in table 1. Main HC in renal AAV was crescentic, mixed, focal and sclerotic respectively. Eight patients had not biopsy performed. IF was positive for C3 deposits in 20 patients (35.7%). Half of the patients presented <50% normal glomeruli.The treatment of renal involvement in AAV in our cohort was as follows: 83.9% (47) corticosteroids (CS) and cyclophosphamide (of which 40 received intravenous and 7 oral cyclophosphamide; and 12 patients associated plasma exchange (PE) with this treatment), 5.36% CS alone, 2 patients received CS and mycophenolate; 1 CS and rituximab, 1 CS and PE, and 2 patients received no treatment. A total of 13 patients received PE and 18 RRT. The mean time to RRT was 65.44±32.72 months. Relapses were not uncommon, 33.93% of the patients presented ≥1 relapse and 10.71% presented ≥2.Infections were very frequent since they were present in 91.07% of the patients. Other frequent non-immunological complications observed in the follow-up of these patients were thrombosis in 31.14%, cardiovascular events in 28.57% and cancer in 19.64%.Patients with ANCA-PR3+ were younger at diagnosis (p<0.001), were more likely to present cardiac (p=0.045) and ORL involvement (p<0.001). However, neither ANCA-PR3+ nor ANCA-MPO+ were specifically associated with the need of RRT or higher risk of death in our cohort. Use of CS alone for the treatment of renal AAV was associated with higher mortality (p=0.006) but CS and cyclophosphamide with lower mortality (p=0.044). ANCA-negative patients were more likely to receive no treatment. Having <50% normal glomeruli and C3 deposits on IF were associated with an increased need for RRT. Presenting focal disease on HC was protective for the need of RRT. Older age at diagnosis, systemic involvement of AAV and need of RRT was associated with higher mortality.Conclusion:AAVs are complex vasculitides with frequent renal involvement. Increased C3 deposition, non-focal histological forms, and <50% normal glomeruli were related to the need for RRT. In turn, the need for RRT, a later age at diagnosis, and systemic involvement were associated with higher mortality. Holistic and multidisciplinary early management of AAVs in experience centers can help improve renal prognosis and decrease mortality.References:[1]Binda et al. ANCA-associated vasculitis with renal involvement. J Nephrol. 2018 Apr;31(2):197-208.[2]Kronbichler et al. Clinical associations of renal involvement in ANCA-associated vasculitis. Autoimmun Rev. 2020 Apr;19(4):102495.Disclosure of Interests:None declared
Antineutrophil Cytoplasmic Antibodies in Patients Treated With Methimazole
