Efficacy and Safety of Immunoglobulin Associated With Rituximab Versus Rituximab Alone in Childhood-Onset Steroid-dependent Nephrotic Syndrome

Inclusion Criteria: * Childhood onset nephrotic syndrome (first flair \<18 years) * ≥ 2 years old at inclusion * Steroid-dependent: * Patient with at least 2 relapses confirmed during the decay of corticosteroids or within 2 weeks following steroids discontinuation. * Patient with at least 2 relapses including one under steroidsparing agent (MMF, Calcineurin inhibitors, cyclophosphamide, Levamisole) or within 6 months of treatment withdrawal. * or with frequent relapses: · 2 or more relapses within 6 months after initial remission or 4 or more relapses within any 12-month period. * with a relapse within 3 months prior to inclusion * In remission: Protein-over-creatinine ratio ≤ 0.2g/g (≤ 0.02g/mmol) Exclusion Criteria: * Patients with steroid-resistant nephrotic syndrome; * Patients with genetic nephrotic syndrome; * Patients previously treated with rituximab; * Patients with no affiliation to a social security scheme (beneficiary or legal); * Prior Hepatitis B, Hepatitis C or HIV infection; * Pregnancy or breastfeeding. * Patients with hyperprolinaemia, * Known hypersensitivity to one of the study medication, * Scheduled and not postponable injection of live attenuated vaccine * Protected adults * Patients with neutrophils \< 1.5 G/L and/or platelets \< 75 G/L