Redefining Renal Remission in ANCA-Associated Vasculitis: A Contemporary Review and Proposal for New Criteria

Kidneys are among the major organs affected in Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and achieving renal remission remains a central goal of disease management. Accurate distinction between active disease and remission is essential for guiding immunosuppressive therapy. However, a universally accepted definition of remission is still lacking, and the ability to reliably measure it remains challenging. Traditional markers, including ANCA titres and proteinuria, have notable limitations in reflecting true disease activity. This review examines how disease activity and remission have been defined in the literature and clinical trials, and evaluates the strengths and limitations of currently available traditional, serological, and novel biomarkers, alongside histological confirmation. Drawing on existing evidence, we propose a candidate set of criteria for defining renal remission in AAV, intended to inform future consensus-driven validation rather than for immediate clinical use, and highlight the urgent need for such validation studies.