Rituximab in the First Episode of Paediatric Nephrotic Syndrome

Inclusion Criteria: 1. Children between 1 and 18 years with Steroid-Sensitive Nephrotic Syndrome (nephrotic-range proteinuria and either hypoalbuminemia or edema when albumin level is not available) 2. Estimated glomerular filtration rate (eGFR) ≥90 ml/min per 1.73 m2 at study entry 3. Remission at study entry 4. the cluster of differentiation antigen 20 (CD20) positive cells in peripheral blood ≥1% total lymphocytes 5. No immunosuppressive agents have been used within 3 months of enrolment, except for the use of corticosteroid to treat nephrotic syndrome 6. Provision of consent by a legal representative using a document approved by the institutional review board after receiving an adequate explanation of this clinical trial. For children ages 8-18, written assent is required using age-appropriate and background-appropriate documents Exclusion Criteria: 1. Diagnosis of secondary NS 2. Patients showing one of the following abnormal clinical laboratories 3. values: leukopenia (white blood cell count ≤3.0\*109/L); moderate and severe anemia (hemoglobin \<9.0g/dL); thrombocytopenia (platelet count \<100\*1012/ L); positivity of autoimmunity tests (ANA, Anti DNA antibody, ANCA) or reduced C3 levels; Alanine aminotransferase or aspartate aminotransferase \> 2.5× upper limit of normal value 4. Presence of severe or chronic infections within 6 months before assignment: tuberculosis or in whom tuberculosis is suspected; Epstein-Barr virus or cytomegalovirus; hepatitis B or hepatitis C or hepatitis B virus carrier, human immunodeficiency virus or other active viral infections 5. Live vaccination within last month 6. Patients with poorly controlled hypertension 7. Patients with severe brain, heart, liver, and other important organs, as well as blood and endocrine system diseases 8. Presence or history of autoimmune diseases, primary immunodeficiency, or tumor 9. Patients with a known allergy to Rituximab and its excipients 10. Assessed to be unfit for participation by the investigators (patients highly likely to be lost to follow-up or provide inaccurate data, for example, patients with alcohol or other substance misuse disorders, and patients with psychological disorders)