Repeat Kidney Biopsies in Anti-Neutrophil Cytoplasmic Autoantibody-Associated Vasculitis: Clinical and Histologic Progression

ANCA-associated vasculitis (AAV) is a multi-systemic autoimmune disease that affects small and medium blood vessels. AAV includes 3 distinct clinical phenotypes, granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Circulating autoantibodies to neutrophil myeloperoxidase and/or proteinase 3 are present in majority of patients with AAV while 10% of patients can be ANCA-negative. Despite recent advancements in induction and maintenance therapies, relapse remains common.