Universal STAR-T Cell Injection in R/R Autoimmune Diseases.

Inclusion Criteria:

1. Age ranges from 18 to 65 years old (including threshold), regardless of gender.
2. Confirmed diagnosis of a connective tissue disease (CTD) according to the latest international classification criteria, including but not limited to Systemic Lupus Erythematosus (SLE), Primary Sjögren's Syndrome (pSS), Antiphospholipid Syndrome (APS), and Undifferentiated Connective Tissue Disease (UCTD).

3. Confirmed diagnosis of CTD-associated immune thrombocytopenia meeting one of the following:

   Platelet count < 30 × 10⁹/L; Platelet count < 50 × 10⁹/L accompanied by bleeding tendency.

4. Bone marrow morphology consistent with the characteristics of immune thrombocytopenia (ITP).
5. Prior Treatment History: Failure to achieve partial remission (PR) after receiving at least one of the following regimens continuously for ≥ 3 months, or inability to maintain efficacy during glucocorticoid tapering:

At least one course of glucocorticoid pulse therapy; Or high-dose glucocorticoids combined with one or more immunosuppressants (including biologics).

6. 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. 7. 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.

8. Voluntary participation with signed informed consent and compliance.

Exclusion Criteria:

• Subjects who meet any of the following exclusion criteria will not be admitted to the study:

  1. Individuals with a severe history of drug allergies or those with an allergic constitution;
  2. Individuals with existing or suspected uncontrolled or treatable fungal, bacterial, viral, or other infections;
  3. Subjects with central nervous system diseases (excluding those with a history of epilepsy, psychiatric disorders, organic brain disease syndromes, cerebrovascular accidents, encephalitis, or central nervous system vasculitis resulting from the underlying disease);
  4. Subjects whose cardiac function cannot tolerate the study interventions;
  5. Subjects with congenital immunoglobulin deficiencies;
  6. Subjects with a history of malignant tumors within the past five years;
  7. Subjects with end-stage renal failure;
  8. Subjects who are positive for hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (HBcAb) with peripheral blood HBV DNA titers exceeding the upper limit of detection; subjects who are positive for hepatitis C virus (HCV) antibody and peripheral blood HCV RNA; subjects who are positive for human immunodeficiency virus (HIV) antibody; and subjects who are positive for syphilis testing;
  9. Subjects with psychiatric disorders or severe cognitive dysfunction;
  10. Subjects who have participated in other clinical trials within the past three months prior to enrollment;
  11. Subjects who have received immunosuppressive agents with therapeutic effects on the disease within five half-lives prior to enrollment or biological agents within four weeks prior to enrollment;
  12. Pregnant women or women planning to become pregnant;
  13. Subjects whom the investigator believes have other reasons that preclude their inclusion in this study.