The lower relapse rate in this study was partly due to the ANCA subtype (PR3-ANCA+ patients relapse more than MPO-ANCA+ patients) as our cohorts were MPO-ANCA+ patients and most patients with AAV-PD except one who received kidney transplantation ceased immunosuppression without active extrarenal manifestation of vasculitis after undergoing PD (19, 20). The gene discussed is MPO; the disease is anti-neutrophil cytoplasmic antibody-associated vasculitis.