Pathogenesis of ANCA-associated vasculitides in 2021: An update

Anticytoplasmic neutrophil antibodies (ANCA)-associated vasculitis (AAV) are rare systemic immune mediated diseases characterized by small vessel necrotizing vasculitis and/or respiratory tract inflammation. Over the last 2 decades, anti-MPO vasculitis mouse model has enlightened the role of ANCA, neutrophils, complement activation, T helper cells (Thl, Th17) and microbial agents. In humans, CD4T cells have been extensively studied, while the dramatic efficacy of rituximab demonstrated the key role of B cells. Many areas of uncertainty remain, such as the driving force of GPA extra-vascular granulomatous inflammation and the relapse risk of anti-PR3 AAV pathogenesis. Animal models eventually led to identify complement activation as a promising therapeutic target. New investigation tools, which permit in depth immune profiling of human blood and tissues, may open a new era for the studying of AAV pathogenesis. (C) 2021 Societe Nationale Francaise de Medecine Interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.

Automated summary

AAV is a group of rare systemic immune-mediated diseases characterized by small vessel necrotizing vasculitis and respiratory tract inflammation. Research in animal models and in humans has identified the roles of ANCA, neutrophils, T helper cells, B cells, complement activation, and other factors in the pathogenesis of AAV. New investigation tools may lead to a better understanding of the disease mechanisms and potential therapeutic targets.