• Meet the 2019 EULAR/ACR classification criteria for systemic lupus erythematosus (SLE).

• SLEDAI-2000 score \>6.

• Have at least one BILAG-2004 Grade A or two Grade B organ domain scores, or both.

• Failure to respond to conventional therapy or disease relapse after remission. Conventional therapy: Glucocorticoids (≥1 mg/kg/day) combined with cyclophosphamide and ≥1 of the following immunosuppressants for \>6 months: antimalarials, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine A, and/or biologics (e.g., rituximab, belimumab, telitacicept).

• Aged 18-65 years; both genders eligible.

• Adequate organ function:Bone marrow function: White blood cell count ≥3×10⁹/L. Absolute neutrophil count ≥1×10⁹/L (without colony-stimulating factor therapy within 2 weeks prior to testing). Hemoglobin ≥60 g/L; Liver function: Alanine aminotransferase (ALT) ≤3×upper limit of normal (ULN). Aspartate aminotransferase (AST) ≤3×ULN. Total bilirubin (TBIL) ≤1.5×ULN (except Gilbert's syndrome, TBIL ≤3.0×ULN); Renal function: Creatinine clearance (CrCl) ≥60 mL/min (calculated by Cockcroft-Gault formula); Coagulation: International normalized ratio (INR) ≤1.5×ULN. Prothrombin time (PT) ≤1.5×ULN; Cardiac function: Hemodynamic stability with left ventricular ejection fraction (LVEF) ≥55%.

• Agrees to use double barrier methods, condoms, oral or injectable contraceptives, or intrauterine devices during the study period and for one year after taking the study medication. Females of childbearing potential must have a negative serum HCG test within 7 days prior to enrollment and must not be lactating.

• Voluntarily participate in the study, provide written informed consent, and demonstrate good compliance with follow-up.