Methods. This prospective, sequential, open, study will include 20 patients with histology evidence of MCD or FSGS and steroid-dependant or multirelapsing NS, who are on stable complete or partial remission since at least 1 month and, based on their previous history, are expected to invariably relapse after steroid/immunosuppression withdrawal. After baseline evaluation of clinical, laboratory and kidney function parameters [including glomerular filtration rate (GFR), renal plasma flow (RPF), albumin and sodium fractional clearance and the glomerular albumin permeability assay (Palb)], patients will receive one Rituximab infusion that will be repeated 1 week later if CD20 cells are not fully depleted from the circulation. Then ongoing immunosuppression will be progressively tapered up to complete withdrawal over 6 to 9 months. 24h proteinuria will be monitored monthly and spot urine will be tested daily by albustix to early detect disease relapses. Baseline evaluations will be repeated at study end (1 year). Relapses will be treated with high-dose steroids as per center practice and the last immunosuppressive therapy effective in preventing disease reactivation will be reintroduced.