Umbilical Cord Mesenchymal Stem Cells (UC-MSC) in the Treatment of Systemic Sclerosis

Exclusion Criteria

• •1. At screening, the patient's percent predicted forced vital capacity (FVC) is \<50%.
• •2. Previously diagnosed with moderate or severe pulmonary arterial hypertension, or systolic pulmonary artery pressure \>45 mmHg measured by echocardiography at screening.
• •3. Presence of newly onset or worsening of pre-existing clinical symptoms requiring hospitalization as judged by the investigator prior to screening, including the following:
• •① Myocardial infarction, stroke, scleroderma renal crisis, severe intestinal disease, or uncontrolled severe hypertension (≥160/100 mmHg) with newly onset or worsening of pre-existing clinical symptoms within 6 months.
• •② Unstable ischemic heart disease, uncontrolled cardiac arrhythmia, heart failure (New York Heart Association Class III/IV), left ventricular ejection fraction \<50% by echocardiography, renal insufficiency, or renovascular hypertension within 3 months.
• •4. Presence of other autoimmune connective tissue diseases other than systemic sclerosis at screening, except for patients with secondary Sjögren's syndrome who are permitted to participate in this trial.
• •5. Any of the following laboratory abnormalities at screening:
• •① Hematologic abnormalities: hemoglobin \<90 g/L; white blood cell count \<3.0×10\^9 /L; absolute neutrophil count \<1.5×10\^9 /L; platelet count \<90×10\^9 /L.
• •② Hepatic abnormalities: ALT or AST \>3× upper limit of normal (ULN); total bilirubin \>3× ULN.
• •③ Renal abnormalities: estimated glomerular filtration rate (eGFR) \<60 mL/min/1.73 m², or any uncontrolled, clinically significant laboratory abnormality that may interfere with data interpretation or subject participation.
• •6. Positive test for human immunodeficiency virus antibody (anti-HIV-Ab), active syphilis, active hepatitis C (positive for HCV antibody with detectable HCV-RNA), or positive for HBsAg with detectable HBV-DNA at screening; or history of severe active or recurrent bacterial, viral, fungal, parasitic, or other infections at screening.
• •7. Receipt of inactivated or live-attenuated vaccine within 2 months prior to enrollment.
• •8. Any of the following within 3 months prior to enrollment:
• •① Major trauma or major surgery (including joint surgery), or need for major surgery during the study period that, in the investigator's opinion, would pose an unacceptable risk to the subject.
• •② Treatment with plasmapheresis or extracorporeal photopheresis.
• •③ Participation in any other interventional clinical trial.
• •9. Prior treatment with stem cell-based therapy less than 3 months before enrollment.
• •10. History of any malignancy within 5 years prior to enrollment, except for adequately treated or resected basal cell carcinoma or squamous cell carcinoma of the skin, or cervical carcinoma in situ.
• •11. Intolerance or contraindication to the study treatment, including any of the following:
• •① Allergy to albumin contained in the excipients of the investigational product.
• •② Absence of peripheral venous access.
• •12. Heavy smoking, heavy drinking, or drug abuse within 12 months prior to screening or during the screening period:
• •① Heavy smoking defined as an average of ≥5 cigarettes per day within 3 months prior to screening.
• •② Heavy drinking defined as consumption of more than 14 units of alcohol per week within 3 months prior to screening (1 unit = 350 mL of beer, 45 mL of liquor, or 150 mL of wine).
• •③ Drug abuse defined as a history of drug addiction or drug abuse.
• •13. Plan to father or bear children within at least 6 months following the last dose, or unwilling to use effective contraception with their partner, or plan to donate sperm or eggs.
• •14. Any other condition that, in the investigator's judgment, makes the subject unsuitable for participation in this study.