MPO-ANCA Rapidly Progressive Glomerulonephritis with Immune Deposits.

INTRODUCTION Antineutrophil cytoplasmic autoantibody associated (ANCA) vasculitides include a group of disorders that affect predominantly small-sized arteries. ANCA-associated conditions include granulomatosis with polyangiitis and microscopic polyangiitis.1 These conditions typically present as focal necrotizing lesions without immune complex depositions on histology. There are two major categories of ANCA based on different autoantibody targets. Cytoplasmic ANCA (c-ANCA) refers to the diffuse cytoplasmic pattern of autoantibodies on immunofluorescence microscopy while perinuclear ANCA (p-ANCA) demonstrates perinuclear staining. Anti-proteinase 3 antibodies commonly are found in c-ANCAs while anti-myeloperoxidase is the major p-ANCA antibody. Induction therapy consists of steroids with either cyclophosphamide or rituximab. ANCA vasculitides classically demonstrate pauci-immune glomerulonephritis on microscopic examination, however, there were reported cases of immune complex deposition. This case report presents a patient with immune complex deposition and nephrotic range proteinuria.