A 43-year-old male patient with onset of edema caused by nephrotic proteinuria and low titer of anti-M type phospholipase-A2-receptor (PLA2R) antibody was diagnosed as idiopathic membranous nephropathy by renal biopsy. Administrated with prednisone 40 mg once a day and cyclosporine 100 mg twice a day as front-line regimen, the patient relapsed after transient partial remission. When treatment was combined with cyclophosphamide 100 mg once a day, the 24-hour total urine protein and titer of anti-PLA2R antibody were even elevated. Therefore, the patient received rituximab 1 g intravenously in April 2019, October 2019 and October 2020 respectively. CD19 positive B lymphocytes in peripheral blood were eliminated from 71/μl to zero. Immunosuppressants and corticosteroids were withdrawn successively. On the last follow-up in November 2020, the anti-PLA2R antibody was negative, and the 24-hour total urine protein and serum albumin was 4.4 g and 34 g/L, respectively. This case suggested the potential efficacy of rituximab for refractory membranous nephropathy. Further studies should explore whether the titer of anti-PLA2R antibody indicates the dose of rituximab.
患者男性，43岁。以水肿起病，查24h尿蛋白定量4.66 g，抗M型磷脂酶A2受体（PLA2R）抗体水平25.3 EU/ml，肾脏穿刺病理确诊特发性膜性肾病（MN）。初期口服泼尼松40 mg每日1次，环孢素A 100 mg每日2次治疗，部分缓解后复发，联合环磷酰胺100 mg每日1次口服无效，监测24h尿蛋白定量升至10.8 g，抗PLA2R抗体水平升至496 RU/ml，CD19+B细胞计数71个/μl，遂分别予3次利妥昔单抗1 g静脉输液治疗，并先后停用环孢素A、环磷酰胺及泼尼松。末次随访CD19+B细胞0个/μl，抗PLA2R抗体阴性，血白蛋白34 g/L，24 h尿蛋白定量4.4 g。本例患者提示了利妥昔单抗在难治性膜性肾病中的治疗效果，以CD19+B细胞计数或抗PLA2R抗体水平作为再次使用利妥昔单抗治疗的指征，需进一步思考。.