Activation of neutrophils by ANCA ("Anti-Neutrophil Cytoplasm Antibodies") and subsequent microvascular endothelial cell damage is the main feature of ANCA-associated vasculitis (AAV), a severe autoimmune disease that often targets the kidney. There is no specific treatment for AAV to date and 25% of patients with renal damage evolve towards end-stage renal disease, requiring dialysis and kidney transplantation. In addition, there is no reliable biological marker of the disease activity available, which makes the diagnostic, follow-up and treatment of patients difficult. Therefore, the identification of new therapeutic targets and non-invasive biomarkers constitutes a major clinical challenge to improve AAV patients care and to ameliorate their renal outcome.