Rituximab Combined With Cyclosporine Versus Rituximab Alone in the Treatment of iMN

Inclusion Criteria: * idiopathic MN with or without diagnostic biopsy * Female, must be post-menopausal, sterile or have effective method of contraception * must be off steroid or mycophenolate mofetil for \>1 month and alkylating agents for \> 6 months * Angiotensin-converting-enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) for ≥3 months prior to randomization with controlled blood pressure or if patients is intolerant to ACEI/ARB * proteinuria ≥4g/24h using the average from two 24-hour urine samples collected within 2 weeks of each other, and decreased ≤50% from baseline. * estimated glomerular filtration rate (eGFR) ≥40ml/min/1.73m2 Exclusion Criteria: * presence of active infection or a secondary cause of MN * diabetes mellitus: to exclude proteinuria secondary to diabetic nephropathy. * pregnancy or breast feeding * history of resistance to CsA or other calcineurin inhibitors(CNI), RTX or alkylating agents. * Patients who previously achieved remission after treatment of CNI, RTX or alkylating agents but relapsed off CNI after 3 months, or relapsed off RTX or alkylating agents after 6 months, are eligible.