Advances in the Diagnosis, Treatment and Prognosis of ANCA-Associated Glomerulonephritis

ANCA-associated vasculitis (AAV) with kidney involvement represents small-vessel vasculitis, characterized by rapidly progressive glomerulonephritis and a high risk of end-stage kidney disease (ESKD) and increased mortality. AAV typically presents with multisystem involvement, with renal manifestations occurring more frequently in microscopic polyangiitis (MPA) (90–100%) and granulomatosis with polyangiitis (GPA) (50–80%). The classic clinical presentation includes acute kidney injury with hematuria and proteinuria, accompanied by ANCA positivity (MPO-ANCA or PR3-ANCA). Histologically, the predominant pattern is segmental necrotizing glomerulonephritis with crescent formation. Treatment consists of two phases: (a) induction of remission with a lower cumulative dose of glucocorticoids (according to the reduced-dose PEXIVAS regimen) in combination with rituximab or cyclophosphamide and (b) maintenance of remission with rituximab for 2–4 years. The C5a receptor inhibitor avacopan can be used as a steroid-sparing agent in patients with severe kidney involvement or at high risk of corticosteroid-related complications. Beyond the traditional markers of disease activity (hematuria, proteinuria, eGFR), novel biomarkers such as urinary soluble CD163, MCP-1, complement activation products (C5a, sC5b-9), and urinary Treg/Th17 profiles have demonstrated prognostic value. Early diagnosis and prompt initiation of immunosuppressive therapy significantly improve both kidney and overall survival, while prevention of relapses and long-term complications plays a key role in improving the long-term prognosis of patients with AAV.