A Study of Anti-CD19/BCMA Universal CAR-T Cell Therapy RD06-05 in Patients With Autoimmune Diseases.

Inclusion Criteria: 1. Willing and able to provide written informed consent. 2. Aged ≥18 years and ≤75 years. 3. Adequate organ function defined as: 1. Bone marrow function: Defined as absolute neutrophil count (ANC) ≥1500/μL, absolute lymphocyte count (ALC) ≥100/μL, hemoglobin (Hb) ≥80 g/L, and platelet count (PLT) ≥50,000/μL. Transfusions and growth factors must not have been used within 7 days prior to screening to meet these criteria. 2. Liver function: Defined as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤3 × upper limit of normal (ULN), and total bilirubin \<1.5 × ULN (or \<3.0 × ULN for subjects with Gilbert's syndrome). 3. Coagulation function: Defined as international normalized ratio (INR) or partial thromboplastin time (PTT) ≤1.5 × ULN. 4. Pulmonary function: Defined as dyspnea ≤ Grade 1 per CTCAE and oxygen saturation (SpO₂) ≥92% on room air (by pulse oximetry). 4. Female subjects of childbearing potential must have a negative serum or urine pregnancy test. Females who are surgically sterile or postmenopausal for at least 2 years are considered not of childbearing potential. 5. From the time of signing the informed consent form until 6 months after the completion of RD06-05 infusion, female subjects of childbearing potential and male subjects with partners of childbearing potential must use highly effective methods of contraception. Inclusion Criteria for Subjects with Anti-GBM Disease: Diagnosis of anti-GBM disease according to the 2012 Chapel Hill Consensus Conference definitions, meeting both of the following criteria: 1. Positive for anti-GBM antibody (based on historical or screening test results); 2. Evidence of renal involvement at screening, defined as: 1. Presence of active, pathologically confirmed anti-GBM disease (renal biopsy must have been performed within 1 year prior to the screening visit or during the screening period); and 2. Accompanied by proteinuria and hematuria. Inclusion Criteria for Subjects with SLE/LN: 1. Diagnosis of SLE according to the 2019 European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) classification criteria or the 2012 Systemic Lupus International Collaborating Clinics (SLICC) classification criteria. 2. Positive for antinuclear antibody (ANA), and/or anti-double-stranded DNA (anti-dsDNA) antibody, and/or anti-Smith (anti-Sm) antibody at screening. 3. SLEDAI-2K score \> 6 points at screening. Inclusion Criteria for Subjects with AAV/AAGN: 1. Diagnosis of microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA) according to the 2022 ACR/EULAR classification criteria for ANCA-associated vasculitis. 2. Positive for anti-myeloperoxidase (MPO-ANCA) antibody or anti-proteinase 3 (PR3-ANCA) antibody at screening or based on historical testing. 3. For AAV without renal involvement: A Birmingham Vasculitis Activity Score (BVAS) version 3 score of ≥3 at screening, indicating active vasculitis. Inclusion Criteria for Subjects with MN: 1. Diagnosis of primary (idiopathic) membranous nephropathy confirmed by renal biopsy pathology (the renal biopsy must have been performed within 2 years prior to screening or during the screening period). 2. Meeting the criteria for high-risk or relapsed/refractory membranous nephropathy: High-risk patients, defined as meeting any of the following criteria: 1. Normal eGFR with urine protein \>3.5g/24h, a reduction of \<50% in urine protein after 6 months of ACEI/ARB treatment, and serum albumin \<25 g/L or anti-PLA2R antibody \>50 RU/mL; 2. eGFR \<60 mL/min/1.73m² and/or urine protein \>8g/24h for more than 6 months. Refractory/Relapsed patients: Refractory patients are defined as those resistant to prior immunosuppressive therapy (persistent urine protein ≥3.5g/24h with a \<50% reduction from baseline). Relapsed patients are defined as those who achieved complete or partial remission with prior immunosuppressive therapy but subsequently developed recurrent urine protein ≥3.5g/24h. Inclusion Criteria for Subjects with SSC: 1. Diagnosis of systemic sclerosis (SSc) according to the 2013 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) classification criteria. 2. Diagnosis of diffuse cutaneous SSc at screening. Inclusion Criteria for Subjects with IIM: 1.Diagnosis of idiopathic inflammatory myopathy (IIM) according to the 2017 ACR/EULAR classification criteria (including probable or definite diagnosis, corresponding to a probability score of ≥55%). The subtypes include dermatomyositis (DM), anti-synthetase syndrome (ASS), and immune-mediated necrotizing myopathy (IMNM). Inclusion Criteria for Subjects with IgAN: 1. Definitive diagnosis of primary IgA nephropathy confirmed by renal biopsy pathology results obtained within 2 years prior to screening. 2. At screening, 24-hour urinary protein ≥1 g/24 h, or urine protein-to-creatinine ratio (UPCR) ≥0.75 g/g. 3. At screening, estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m². 4. Standard therapy must have been completed for a minimum of 3 months before screening, with a stable drug dose maintained for at least 4 weeks; standard therapeutic agents include ACEIs, ARBs, and/or SGLT2 inhibitors. 5. At screening, the subject's blood pressure shall be controlled at ≤150/90 mmHg. Exclusion Criteria: 1. Subjects with SLE/LN: 1. Severe active central nervous system (CNS) lupus, including psychosis, seizures, lupus headache, or other signs/symptoms associated with neuropsychiatric lupus, as assessed by a qualified specialist during screening. 2. Drug-induced or secondary lupus. 2. Subjects with AAV/AAGN: 1. Drug-induced or secondary AAV/AAGN. 2. Presence of alveolar hemorrhage requiring invasive ventilatory support at screening. 3. Subjects with Anti-GBM Disease: 1. Anuria for more than 7 days. 2. Dialysis dependence for more than 30 days. 3. Ongoing moderate or severe pul