A Clinical Study of YTS109 Cell in R/R Autoimmune Diseases

Inclusion Criteria: * Subjects must meet both the following common inclusion criteria and disease-specific inclusion criteria simultaneously to be eligible for participation in this study: Common inclusion criteria: 1. Age ranges from 18 to 65 years old (including threshold), regardless of gender. 2. Detection of positive CD19 expression on peripheral blood B cells by flow cytometry. 3. Essential Organ Function Criteria: <!-- --> 1. Bone marrow: Neutrophils ≥1×10\^9/L (within 2 weeks, excluding granulocyte colony-stimulating factor use). Hemoglobin ≥60 g/L. 2. Liver: ALT/AST ≤3×ULN (disease-related elevations permitted). TBIL ≤1.5×ULN (disease-related elevations permitted). 3. Renal: CrCl≥30mL/min (Cockcroft-Gault formula, excluding acute declines). 4. Coagulation: INR/PT ≤1.5×ULN. 5. Cardiovascular: Hemodynamic stability. 4. Fertile females or males with partners of childbearing age must use medically approved contraception or abstain during and ≥12 months post- treatment. Negative serum HCG test (within 7 days pre-enrollment) for fertile females; non-lactating. 5\. Voluntary participation with signed informed consent and compliance. Specific inclusion criteria: Relapsing and refractory systemic lupus erythematosus: 1\. Meeting the EULAR/ACR 2019 SLE Classification Criteria; 2. SELENA SLEDAI≥6, or the presence of significant organ involvement, such as lupus nephritis (LN), etc; 3. Definition of relapsing and refractory condition: Persistence of disease activity or recurrence of disease activity after remission, despite undergoing treatment with a regimen containing at least two immunosuppressive agents (including glucocorticoids, cyclophosphamide, tacrolimus, mycophenolate mofetil (MMF), and cyclosporine) and/or biological agents for a minimum duration of two months. Relapsing and refractory Sjögren's syndrome: 1. Meeting the 2002 American-European Consensus Group (AECG) criteria or the 2016 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for primary Sjögren's syndrome; 2. Having a disease activity score of EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) ≥ 6; 3. Testing positive for anti-SSA/Ro antibodies; 4. Definition of relapsing and refractory condition: Persistence of disease activity or recurrence of disease activity after remission, despite undergoing conventional treatment for more than six months. Definition of conventional treatment: Administration of glucocorticoids in combination with any of the following immunosuppressive agents or biological agents: cyclophosphamide, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, as well as biological agents including rituximab, belimumab, telitacicept, etc. Relapsing and refractory Sjogren's Syndrome: 1. Meeting the 2013 American College of Rheumatology (ACR) classification criteria for systemic sclerosis; 2. Testing positive for systemic sclerosis-related antibodies; 3. Presenting with diffuse cutaneous sclerosis or active interstitial lung disease (as indicated by ground-glass opacities on high-resolution computed tomography, HRCT); 4. Definition of relapsing and refractory condition: Persistence of disease activity or recurrence of disease activity after remission, despite undergoing conventional treatment for more than six months. Definition of conventional treatment: Administration of glucocorticoids and cyclophosphamide, in combination with any one or more of the following immunomodulatory agents: antimalarial drugs, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, as well as biological agents including rituximab, belimumab, telitacicept, etc.; 5. Definition of progressive condition: Demonstrating rapid skin progression (an increase in modified Rodnan skin score, mRSS, of \>25%) or pulmonary disease progression (a 10% decrease in forced vital capacity, FVC, or a \>5% decrease in FVC accompanied by a 15% decrease in diffusion capacity for carbon monoxide, DLCO). Note: Meeting either criterion 4 or 5 is sufficient. Relapsing and refractory Inflammatory Myopathy: 1. Meeting the 2017 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for inflammatory myopathies (including dermatomyositis, DM; polymyositis, PM; antisynthetase syndrome, ASS; and necrotizing myopathy, NM); 2. Testing positive for myositis-specific antibodies; 3. For patients with muscle involvement, having a Manual Muscle Testing-8 (MMT-8) score below 142 and at least two abnormal findings among the following five core measures (Physician's Global Assessment, PhGA; Patient's Global Assessment, PtGA, or extra-muscular disease activity score ≥ 2 points; Health Assessment Questionnaire, HAQ, total score ≥ 0.25; muscle enzyme levels 1.5 times the upper limit of normal range); or having an MMT-8 score ≥ 142 but presenting with active interstitial lung disease (as indicated by ground-glass opacities on high-resolution computed tomography, HRCT); 4. Definition of relapsing and refractory condition: Persistence of disease activity or recurrence of disease activity after remission, despite undergoing conventional treatment for more than six months. Definition of conventional treatment: Administration of glucocorticoids and cyclophosphamide, in combination with any one or more of the following immunomodulatory agents: antimalarial drugs, azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, as well as biological agents including rituximab, belimumab, telitacicept, etc.; 5. Definition of progressive condition: Demonstrating worsening myositis or rapidly progressive interstitial pneumonia. Note: Meeting either criterion 4 or 5 is sufficient. Relapsing and refractory Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis: 1. Meeting the 2022 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) diagn