• Age 6-18 years old (including critical value);

• Diagnosed with SLE according to the 2019 EULAR/ACR SLE classification criteria;

• According to the 2018 ISN/RPS LN standards diagnosed with active Class III or IV LN, with or without a membranous component and the biopsy must be performed within 6 months prior to screening;

• SLEDAI-2000 score ≥8 points;

• Meeting the diagnosis of refractory lupus nephritis,

∙ defined as treatment with two or more immunosuppressants (including glucocorticoids, cyclophosphamide, tacrolimus, mycophenolic acid analogues, leflunomide, and cyclosporine) for more than 6 months without inducing remission or relapse after remission,

‣ accompanied by proteinuria without remission;

• Positive expression of CD19 in peripheral blood B cells determined by flow cytometry;

• Participants had good venous access, no contraindications for cell collection;

• Participants and their guardians sign the informed consent, understand the study procedures and participate in the clinical study voluntarily;

• The functions of important organs are basically normal:

∙ Hematopoietic function (blood routine should meet):

⁃ Lymphocyte count ≥1×109/L,

• White blood cell count ≥3×109/L,

• Neutrophil count ≥1×109/L (no colony-stimulating factor treatment within 2 weeks prior to examination),

• Hemoglobin ≥60g/L;

‣ Liver function:

⁃ ALT≤3×ULN (except elevated ALT caused by inflammatory myopathy),

• AST≤3×ULN (except for elevated AST caused by inflammatory myopathy),

• TBIL≤1.5×ULN (except Gilbert syndrome, total bilirubin ≤3.0×ULN);

‣ Renal function: eGFR ≥30 ml/(min.1.73m2) (Schwartz formula, except abnormal renal function by SLE);

‣ Coagulation function:

⁃ International standardized ratio (INR) ≤1.5×ULN,

• prothrombin time (PT) ≤1.5×ULN;

‣ Heart function: hemodynamic stability;

⁃ Anti-nuclear antibody (ANA) ≥1:80;

⁃ Eastern Cancer Cooperation Group (ECOG) physical status score 0 to 2.