Pathogenesis of ANCA-associated vasculitis: An update

Area of Science:

• Immunology
• Rheumatology
• Pathology

Background:

• Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of rare diseases characterized by small blood vessel inflammation and ANCA presence.
• While ANCA were initially classification markers, evidence now highlights their pathogenic role in activating neutrophils and monocytes, causing vascular damage.

Purpose of the Study:

• To review the main pathogenesis concepts of AAV.
• To explore the putative mechanisms behind the origin of the ANCA autoimmune response.

Main Methods:

• Literature review summarizing current understanding of AAV pathogenesis.
• Discussion of the roles of neutrophils, neutrophil extracellular traps, T-cells, B-cells, and complement in ANCA autoimmunity.

Main Results:

• Neutrophils are central to AAV pathophysiology, acting as effector cells and targets of autoimmunity.
• Neutrophil extracellular traps may facilitate ANCA autoantigen presentation, potentially breaking immune tolerance and initiating autoantibody generation.
• Dysregulated T-cell and B-cell immunity and the complement alternative pathway are implicated in facilitating the ANCA autoimmune response.

Conclusions:

• ANCA plays a direct pathogenic role in AAV through neutrophil activation.
• The precise mechanisms initiating ANCA generation remain unclear but involve complex immune interactions.