This is an investigator-initiated trial aimed at assessing the safety and efficacy of anti-BCMA/CD70 CAR-T cells in the treatment of refractory systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a severe autoimmune disease that can lead to extensive damage in multiple organs and systems, potentially leading to disability and even mortality. Children afflicted with SLE are particularly vulnerable to organ damage, notably affecting the kidneys, and tend to have a more severe and protracted course of the disease compared to adults.

Currently, the primary treatment for SLE relies on glucocorticoids and immunosuppressants to alleviate symptoms. However, due to the absence of a curative treatment, patients typically need to remain on medication indefinitely. In recent years, biological agents such as belimumab and rituximab have been introduced for the treatment of SLE, but these treatments cannot completely eliminate autoimmune B cells in the bone marrow, leading to unsatisfactory overall outcomes. Furthermore, discontinuing these drugs can lead to disease relapse, and there is still no cure for SLE, leaving patients facing the challenges of lifelong medication and an incurable disease. BCMA (B Cell Maturation Antigen) is a receptor primarily expressed on the surface of mature B lymphocytes and plasma cells, serving as a marker protein for B lymphocyte maturation. B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are the main ligands of BCMA. They interact with BCMA to transmit cellular stimulatory signals, activating TRAF-dependent NF-κB and JNK pathways, thereby increasing the proliferation and survival rate of B cells. Importantly, BCMA is highly expressed in long-lived plasma cells,8 which do not express CD19. Therefore, BCMA can compensate for the targeting defect of CD19's insufficient expression in terminally differentiated plasma cells. CD70 is an immune costimulatory molecule for T and B cells, highly expressed on the surface of activated T cells. The CD70/CD27 pathway regulates immunity and tolerance through various mechanisms, including T-cell expansion and survival, costimulation of antigen presentation, germinal center formation, B-cell activation, and antibody production. It plays a crucial role in the differentiation of B cells into plasma cells. Blocking the CD27/CD70 pathway can inhibit the differentiation of memory B cells into plasma cells. Studies have found that CD70 is overexpressed in B cells of SLE patients compared to healthy individuals.

The purpose of this study is to assess the safety and efficacy of the BCMA/CD70 CAR-T cells in the treatment of refractory SLE.

Inclusion Criteria:

1. Age:≥5 years old;
2. Diagnosed with SLE according to the 2019 EULAR/ACR SLE classification criteria；Still in moderate to severe disease activity despite ≥3M of high dose glucocorticoids(prednisone≥1mg/kg/d or other equivalent amount of other steriod ), hydroxychloroquine and at least 2 of the following treatments(cyclophosphamide, MMF, azathioprine, methotrexate, cyclosporin, tacrolimus, sirolimus, leflunomide, telitacicept, Beliumab, and rituximab); or Intolerant to standard treatments;
3. SLEDAI 2K score≥8 points;
4. The functions of important organs are as follows: Cardiac function: Left ventricular ejection fraction (LVEF) ≥55% with no obvious abnormality in electrocardiogram; Renal function: eGFR≥30ML/min/1.73m2；Liver function: Asparagus cochinchinensis transase (AST) and Alanine Aminotransferase (ALT)≤3.0 ULN, Total Bilirubin (TBIL) in serum ≤2.0×ULN; Lung function: No serious lung lesions, SpO2≥92%;
5. No prior CAR-T therapy; or recurrence or poor response after previous treatment with autologous or allogeneic CAR-T targeting CD19 (as assessed by the investigator).
6. Met the standards of leukapheresis or intravenous blood collection, No contraindication for cell collection;
7. Negative pregnancy test for female Subjects of childbearing age, agree to take effective contraceptive measures the first year after CAR-T infusion;
8. Participants or their guardians agrees to participate in the clinical trial and sign the informed consent form which indicating that he/she understands the purpose and procedure of the clinical trial and is willing to participate in the study.

Exclusion Criteria:

1. Central nervous system (CNS) disease: CNS neurolupus requires intervention within 60 days);
2. Severe acute nephritis: Patients who have accepted or was undergoing renal replacement therapy within 3 months prior to transfusion; Or in the investgator's opinion, patients who is likely to have significant kidney disease within 3 moths of the study which need high dose glucocorticoid (prednisone dose≥1mg/kg/day or equivalent amount of other steriod), cyclophosphamide, or MMF treatment;
3. Have a history of congenital heart disease or acute myocardial infarction within 6 months prior to screening; Or severe arrhythmias (including multisource frequent supraventricular tachycardia, ventricular tachycardia, etc.); Or combined with moderate to massive pericardial effusion, serious myocarditis, etc; Or patients with unstable vital signs who need hypertensive drugs；
4. Suffer from other diseases that require long-term use of glucocorticoid or high-dose of immunosuppressive agents;
5. Uncontrollable infection, or active infection that requires systemic treatment within 1 week prior to screening；
6. History of organ transplantation or hematopoietic stem cell transplantation, or ≥Grade 2 GVHD within 2 weeks prior to screening；
7. Hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb) positive and peripheral blood hepatitis B virus (HBV) DNA titer greater than the normal reference value range; Or hepatitis C virus (HCV) antibody positive and peripheral blood hepatitis C virus (HCV) RNA titer greater than the normal reference value range; Or positive for human immunodeficiency virus (HIV) antibodies; Or syphilis test positive; Or cytomegalovirus (CMV) DNA test positive;
8. Received live vaccine within 4 weeks before screening;
9. Tested positive in Blood pregnancy test；
10. Previous or concurrent malignancy；
11. Patients who participated in other clinical study within 1 months prior to enrollment; Any other conditions that the investigators deem it unsuitable for the study.