Objectives. The study is primarily aimed at evaluating whether Rituximab may maintain stable NS remission after tapering and withdrawal of steroid and immunosuppressive therapy in patients with MCD or FSGS and steroid-dependent or multirelapsing NS. Secondarily, the study will assess whether Rituximab allows reducing maintenance doses of steroids and other immunosuppressants (in those who relapse), thus limiting treatment related side effects and costs.