MPO and granulomatosis with polyangiitis: C-ANCA (IIF), proteinase-3 (PR3)-ANCA (ELISA), and myeloperoxidase (MPO)-ANCA (ELISA) in granulomatosis with polyangiitis (GPA) [21], and MPO-ANCA (ELISA) in propylthiouracil-induced vasculitis [22] were IgG1/4-dominant.