⁃ Age 18 to 70 years (inclusive), of any sex.

⁃ Patients with failure of prior single-target CD19 or BCMA therapy, with a washout period of at least 6 months since the last treatment.

⁃ Disease-specific criteria for different indications:

• 1 Relapsed/Refractory Moderate-to-Severe Systemic Lupus Erythematosus (SLE)

∙ Participants must meet all of the following:

⁃ Diagnosis of SLE according to the 2019 EULAR/ACR Classification Criteria for Systemic Lupus Erythematosus.

⁃ At screening, positive antinuclear antibody (ANA) (titer ≥1:80), and/or positive anti-dsDNA antibody, and/or positive anti-Sm antibody.

⁃ Moderate-to-severe disease activity defined as: SLEDAI-2000 score ≥8 at screening; if hypocomplementemia and/or anti-dsDNA antibody contribute to the score, the clinical SLEDAI-2000 score (excluding low complement and/or anti-dsDNA) must be ≥6.

⁃ A documented history of at least 6 months of stable standard-of-care therapy for SLE prior to screening, with active disease for at least 2 months before screening. Standard therapy includes stable use (alone or in combination) of one or more of the following: glucocorticoids (≤20 mg/day prednisone or equivalent), antimalarial drugs (hydroxychloroquine ≤400 mg/day; chloroquine ≤500 mg/day), nonsteroidal anti-inflammatory drugs (NSAIDs), biologic agents (rituximab, belimumab, telitacicept), and other immunosuppressive or immunomodulatory agents including mycophenolate mofetil (≤2 g/day), azathioprine (≤2 mg/kg/day), methotrexate (≤20 mg/week), etc.

• 2 Relapsed/Refractory Systemic Sclerosis (SSc)

∙ Participants must meet all of the following:

⁃ Diagnosis of SSc according to the 2013 EULAR/ACR Classification Criteria for Systemic Sclerosis.

⁃ Diffuse cutaneous SSc as defined by LeRoy et al. (1988), characterized by extensive skin fibrosis involving areas proximal to the elbows and/or knees.

⁃ Presence of interstitial lung disease (ILD) at screening, with forced vital capacity (FVC) 45-70% predicted, or diffusing capacity for carbon monoxide (DLCO) 40-70% predicted.

⁃ Relapsed/refractory disease defined as inadequate response to prior standard therapy or relapse after remission. Standard therapy includes glucocorticoids, cyclophosphamide, and at least one immunosuppressive or immunomodulatory agent administered for ≥6 months (e.g., azathioprine, mycophenolate mofetil, methotrexate, leflunomide, tacrolimus, cyclosporine, rituximab, belimumab, telitacicept).

⁃ Evidence of active disease, defined by at least one of the following: (a) progressive skin involvement at screening with an increase in modified Rodnan skin score (mRSS) ≥10% within the past 6 months; (b) evidence of active ILD, including newly diagnosed ILD within the past 6 months, or (in patients with pre-existing ILD) a decline in FVC ≥10%, or a decline in FVC ≥5% accompanied by a decline in DLCO ≥15% within the past 6 months.

‣ 3 Relapsed/Refractory Idiopathic Inflammatory Myopathies (IIM)

⁃ Participants must meet all of the following:

∙ (1) Diagnosis of IIM with a probability ≥55% according to the 2017 EULAR/ACR Classification Criteria for IIM, and classified as dermatomyositis (DM), polymyositis (PM), or immune-mediated necrotizing myopathy (IMNM).

∙ (2) Active or severe disease defined as: (a) Manual Muscle Testing-8 (MMT-8) score ≤141 (total score 150); and (b) at least two of the following abnormal core set measures: patient global disease activity VAS ≥2 (0-10 scale); physician global disease activity VAS ≥2 (0-10 scale); physician global extramuscular disease activity VAS ≥2 (0-10 scale); Health Assessment Questionnaire Disability Index (HAQ-DI) ≥0.25 (0-3 scale); at least one muscle enzyme level \>1.5 × upper limit of normal (ULN).

• 4 Relapsed/Refractory Sjögren's Syndrome (SS)

∙ Participants must meet all of the following:

⁃ Diagnosis of SS according to the 2016 EULAR/ACR Classification Criteria for Sjögren's Syndrome.

⁃ Positive anti-Ro/SSA antibody at screening.

⁃ Salivary flow rate at screening: stimulated whole salivary flow ≥0.05 mL/min, or unstimulated whole salivary flow ≥0.01 mL/min.

⁃ Active disease defined as ESSDAI score ≥5. 3.5 Relapsed/Refractory Autoimmune Hemolytic Anemia (AIHA)

⁃ Participants must meet all of the following:

∙ (1) Diagnosis consistent with the Chinese Guidelines for the Diagnosis and Treatment of Adult Autoimmune Hemolytic Anemia (2023 Edition).

∙ (2) Evidence of hemolysis, including: anemia based on hemoglobin level; reduced haptoglobin (\<250 mg/L), elevated total bilirubin (≥17.1 μmol/L, predominantly indirect), elevated lactate dehydrogenase (LDH), and reticulocyte percentage \>4% or absolute reticulocyte count \>120 × 10\^9/L; and detection of red blood cell autoantibodies.

∙ (3) Relapsed/refractory disease defined as inadequate response, intolerance, contraindication, or relapse after ≥3 months of treatment with glucocorticoids combined with at least one immunosuppressive agent (e.g., cyclophosphamide, azathioprine, vinca alkaloids, calcineurin inhibitors, mycophenolate mofetil) and/or rituximab.

• 6 Relapsed/Refractory Multiple Sclerosis (MS)

∙ Participants must meet all of the following:

∙ (1) Diagnosis of MS according to the Chinese Guidelines for the Diagnosis and Treatment of Multiple Sclerosis (2023 Edition).

∙ (2) Evidence of disease activity, meeting at least two of the following: (a) clinical relapse within the past 12 months confirmed by a neurologist; (b) MRI activity, including ≥1 new or enlarging T2 lesion or ≥1 new gadolinium-enhancing T1 lesion; (c) disability progression defined by an increase in EDSS score from baseline (≥1.0 point if baseline EDSS ≥1.0; ≥1.5 points if baseline EDSS = 0), sustained for ≥6 months and not attributable to a single relapse.

∙ (3) Relapsed/refractory disease despite ≥12 months of disease-modifying therapy (DMT), including inadequate response, intolerance, contraindication, or relapse during or after treatment discontinuation.

∙ 4\. Documented intolerance or inadequate response to prior therapy with glucocorticoids and at least two additional immunosuppressive or immunomodulatory agents, administered at effective doses for ≥3 months.

∙ 5\. Adequate organ function, defined as:

∙ (1) Hematologic: ANC ≥0.5 × 10\^9/L; platelets ≥20 × 10\^9/L; hemoglobin ≥60 g/L. (2) Coagulation: INR ≤1.5 × ULN and APTT ≤1.5 × ULN. (3) Hepatic: AST and ALT ≤5 × ULN; total bilirubin ≤1.5 × ULN. (4) Renal: serum creatinine ≤1.5 × ULN or creatinine clearance ≥30 mL/min (Cockcroft-Gault).

∙ (5) Cardiac: NYHA class I-II; LVEF ≥50%; no pericardial effusion; and no clinically significant ECG abnormalities.

∙ (6) Pulmonary: oxygen saturation ≥92% on room air; no clinically significant pleural effusion.

∙ 6\. Estimated life expectancy greater than 6 months. 7. Agreement to use effective contraception throughout the treatment period and for 24 months after CAR T-cell infusion; women of childbearing potential must have a negative pregnancy test at screening.

∙ 8\. Ability and willingness to provide written informed consent.