The impact of reclassification by the 2022 ACR/EULAR classification criteria on risk factors for relapse in patients with ANCA-associated vasculitis

Antineutrophil cytoplasmic antibody ( ANCA ) -associated vasculitis ( AAV ) is a rare, life-threatening disease with inflammation of the small vessels. Within AAV, three phenotypes can be specified based on clinical features: granulomatosis with polyangiitis ( GPA ) , microscopic polyangiitis ( MPA ) , and eosinophilic granulomatosis with polyangiitis ( EGPA ) [ 1 , 2 ]. The distinguishment between GPA, MPA, and EGPA is a clinical, physician-based diagnosis. The AAV subtypes can be further specified by their type of ANCAs, i.e. proteinase 3 ( PR3 ) or myeloperoxidase ( MPO ) [ 2 ]. The majority of GPA patients are PR3 + ( 84–85% ) , MPA patients MPO + ( 75–97% ) , and EGPA patients ANCA-negative ( 70% ) [ 2