AAV: ANCA-associated vasculitis; ANCA: anti-neutrophil cytoplasmic antibody; CY: cyclophosphamide; F: female; M: male; MPO: myeloperoxidase; mPSL: methylprednisolone; PR3: proteinase 3; PSL: prednisolone. Here, MPO is linked to anti-neutrophil cytoplasmic antibody-associated vasculitis.