MPO and chronic kidney disease: ANCA: anti-neutrophil cytoplasmic antibody; BMI: body mass index; CY: cyclophosphamide; DM: diabetes mellitus; ESRD: end stage renal disease; MPO: myeloperoxidase; mPSL: methylprednisolone; PR3: proteinase 3; PSL: prednisolone; ST: sulfamethoxazole-trimethoprim