Stratifying participants with small to medium sized vessel vasculitis (GPA, MPA, EGPA, PAN, and UCV) for the absence or presence of ANCA-specific antibodies, we find that inflammatory measures track more closely with disease course in individuals with PR3-AAV and to a lesser extent, ANCA-negative vasculitis. The gene discussed is PRTN3; the disease is eosinophilic granulomatosis with polyangiitis.