Rituximab Trial for Pediatric Nephrotic Syndrome

Inclusion Criteria: (A)steroid/calcineurin inhibitor resistant nephrotic syndrome 1. steroid resistance: no remission after 4 weeks of daily oral corticosteroid (60mg/m2/day) 2. calcineurin inhibitor resistance: no remission after 3 months of therapeutic dose administration of cyclosporine and/or tacrolimus 3. no remission defined by persistent proteinuria of nephrotic range for the last 3 months 4. post-transplant patients were included in the study (B)steroid-dependent nephrotic syndrome 1. Steroid-dependent patients who had been on various known medications (such as corticosteroids, cyclophosphamide, chlorambucil, calcineurin inhibitors, levamisole ..) continuously for more than 2 years 2. definition of dependency: more than two consecutive relapse events in 2 weeks after discontinuation of steroid or calcineurin inhibitor * no improvement in relapsing frequency with calcineurin inhibitor use * unable to continue with calcineurin inhibitor due to side effects * unable to continue with calcineurin inhibitor due to prolonged use (over 2 years) * other conditions in which the clinician considers difficult to control disease with steroids or calcineurin inhibitors only. Exclusion Criteria: * previous rituximab use * secondary nephrotic syndrome * estimated GFR \<60mL/min/1.73m2 or under 50% of age-matched standard GFR * chronic or acute active infection (e.g. hepatitis B,C, herpes, varicella zoster) * prior live vaccine inoculation within 1 month (from the study enrollment) * cardiovascular diseases, pulmonary or pleural diseases * uncontrolled hypertension * leukocytopenia (absolute neutrophil count \<1500/mm3) or thrombocytopenia (\<75000/mm3) * pregnancy