⁃ Common Inclusion Criteria:

• Age ≥ 18 years old (inclusive), regardless of gender.

• Positive expression of CD19 or BCMA on peripheral blood B cells confirmed by flow cytometry.

• Functional requirements for major organs are as follows（Except for abnormalities related to autoimmune disease activity）: 1) Bone marrow function must meet: A. Neutrophil count ≥ 1×109/L (no colony-stimulating factor treatment within 2 weeks before examination); B. Hemoglobin ≥ 60g/L; 2) Liver function: Alanine aminotransferase (ALT) ≤ 3×ULN (excluding ALT elevation due to inflammatory myopathy), aspartate aminotransferase (AST)≤3×Upper limit of normal (ULN) (excluding AST elevation due to inflammatory myopathy), TBIL≤2×ULN (or ≤ 3.0×ULN for subjects with Gilbert syndrome); 3) Renal function: creatinine clearance rate (CrCl) ≥ 30ml/minute (calculated by Cockcroft/Gault formula, acute CrCl decrease due to the target disease is excluded; LN is exluded).

• ECOG score 0-2.

• Female subjects of childbearing potential and male subjects with partners of childbearing potential must use medically approved contraception or abstinence during the study treatment period and for at least 6 months after the end of the study treatment; Female subjects of childbearing potential must have a negative Human chorionic gonadotropin (HCG) test within 7 days before study enrollment and not be lactating.

• Willing to participate in this clinical study, sign an informed consent form, have good compliance, and cooperate with follow-up.

⁃ Disease-Specific Inclusion Criteria

⁃ Refractory/Relapsed Systemic Lupus Erythematosus:

• SLE meeting the 2019 the American College of Rheumatology (ACR) /European League Against Rheumatism (EULAR) and classification criteria.

• Disease activity score SLEDAI-2000 ≥ 8; or with significant organ involvement, such as lupus nephritis (histologically confirmed active nephritis of class III or IV, with or without class V, with an NIH activity index \> 2, evidence of increased chronicity index; urine protein-to-creatinine ratio \> 1.0 g/g, or 24-hour urinary protein \> 1.0 g).

• Definition of refractory or relapsing disease: lack of response after more than 6 months of conventional therapy, or recurrence of disease activity after remission. Conventional therapy is defined as treatment with glucocorticoids in combination with one or more of the following immunomodulatory agents: cyclophosphamide, antimalarial drugs, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, as well as biologics such as rituximab, belimumab, and telitacicept.

⁃ Refractory/Relapsed/Progressive Systemic Sclerosis:

• Scleroderma fulfilling the 2013 ACR classification criteria.

• Positive scleroderma-related antibodies.

• Presence of diffuse cutaneous sclerosis or active interstitial lung disease (high-resolution computed tomography (HRCT) showing ground-glass opacities).

• Definition of relapsed/refractory: Conventional treatment over 6 months remains ineffective, or disease recurrence after remission. Definition of conventional treatment: the use of glucocorticoids , and any one or more of the following immunomodulatory drugs: cyclophosphamide, antimalarials, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, and biologics including belimumab, rituximab, and tocilizumab, etc.

• Definition of progressive: Rapid skin progression (mRSS increase \> 25%); or progression of lung disease (forced vital capacity (FVC) decrease by 10%, or FVC decrease by more than 5% with diffusing capacity of the lung for carbon monoxide (DLCO) decrease by 15%).

⁃ Note: Meeting either criterion 4 or 5 is sufficient.

⁃ Refractory/Relapsed/Progressive Inflammatory Myopathy:

• Inflammatory myopathy fulfilling the 2017 EULAR/ACR classification criteria (including Dermatomyositis (DM), Polymyositis (PM), Anti-Synthetase Syndrome (ASS), and Necrotizing Myopathy (NM)).

• Muscle involvement with Manual Muscle Testing-8 (MMT-8) score less than 142 and at least two abnormalities found among the following five core measurements (Physician Global Assessment (PhGA), Patient Global Assessment (PtGA), or extramuscular disease activity score ≥ 2; Health Assessment Questionnaire (HAQ) total score ≥ 0.25; muscle enzyme levels ≥ 1.5×ULN);

• Definition of relapsed/refractory: Conventional treatment over 6 months remains ineffective, or disease recurrence after remission. Definition of conventional treatment: the use of glucocorticoids , and any one or more of the following immunomodulatory drugs: cyclophosphamide, antimalarials, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, and biologics including belimumab, rituximab, and tocilizumab, etc.

• Definition of progressive: Rapid progression of interstitial lung disease within a short period.

⁃ Note: Meeting either criterion 4 or 5 is sufficient.

⁃ Refractory/Relapsed ANCA-Associated Vasculitis:

• ANCA-Associated Vasculitis fulfilling 2022 ACR/EULAR criteria, including microscopic polyangiitis, granulomatosis with polyangiitis, and eosinophilic granulomatosis with polyangiitis.

• Positive ANCA-associated antibodies (MPO-ANCA or PR3-ANCA positive).

• The Birmingham Vasculitis Activity Scale (BVAS) ≥ 15 points (a total score of 63 points), indicating active vasculitis.

• Definition of refractory/relapsed: Conventional treatment over 6 months remains ineffective, or disease recurrence after remission., or disease recurrence after remission. Definition of conventional treatment: the use of glucocorticoids and any one or more of the following immunomodulatory drugs: cyclophosphamide, antimalarials, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, and biologics including belimumab, rituximab, and tocilizumab, etc.

⁃ Refractory/Relapsed Connective Tissue Disease-associated thrombocytopenia

• Diagnosis of connective tissue disease established according to the latest classification criteria, including but not limited to systemic lupus erythematosus, primary Sjögren's syndrome, antiphospholipid syndrome, and undifferentiated connective tissue disease.

• Confirmed diagnosis of connective tissue disease-associated thrombocytopenia, with platelet count \<30 × 10\^9/L, or \<50 × 10\^9/L accompanied by a bleeding tendency.

• Bone marrow morphology consistent with immune thrombocytopenia.

• Prior treatment with at least one course of corticosteroid pulse therapy, or high-dose corticosteroids in combination with one or more immunosuppressants (including biologics) for at least 3 months, without achieving partial remission, or inability to maintain efficacy during steroid tapering.