The study unequivocally demonstrated that while the group of patients with seronegative AAV did not differ in terms of 5- or 10-year relapse-free rates from the group of GPA and MPA patients with antibodies, a detailed analysis of PR3-ANCA-positive patients showed a higher frequency of vasculitis exacerbations compared to the rest of the AAV population. Here, PRTN3 is linked to microscopic polyangiitis.