Rituximab Combining With Low-Dose Mycophenolate Mofetil on Proliferative Lupus Nephritis in Children

Inclusion Criteria: 1. Children aged 3-18 years old, regardless of sex; 2. SLE patients who meet the 2019 EULAR/ACR SLE criteria or the 2012 SLICC diagnostic criteria; 3. Diagnosed as lupus nephritis and the classification was consistent with proliferative lupus nephritis (type III or IV, with or without type V); 4. White blood cell count ≥3.0×10\^9/L, and lymphocyte count ≥ 0.5× 10\^9/L and CD20 (or CD19)≥1/ul; 5. No cyclophosphamide or rituximab induction therapy was used before enrollment; 6. Informed consent form is signed by the guardian and children over 8 years old; 7. In the active stage of the disease, the 24-hour urine protein quantification ≥25mg/kg, or the urine protein/creatinine ≥1.0mg/mg; 8. Estimated GFR≥60ml/min/1.73m\^2 (improved Swchartz formula). Exclusion Criteria: 1. Patients with lupus encephalopathy; 2. Estimated GFR\<60ml/min/1.73m\^2(Swchartz formula); 3. HBV-antigen positive, HCV or HIV antibody positive; 4. Severe infection (including chronic hepatitis, EB virus or cytomegalovirus infection) and tuberculosis; 5. Allergic to the active ingredients or any auxiliary materials in rituximab, mycophenolate mofetil or cyclophosphamide; 6. Severe heart failure and liver function damage; 7. Patients who is not suitable to participate in this study judged by the researchers.