Fecal Microbiota Transplantation for Steroid-resistant or Relapsed Immune Thrombocytopenia

Inclusion Criteria: 1. Aged 18 to 70 years, regardless of gender. 2. Patients diagnosed with immune thrombocytopenia (ITP) in line with the diagnostic criteria, and with a disease course of ≥ 12 months (chronic ITP). 3. Meeting the definitions of corticosteroid resistance or relapse (resistance: platelet count remains \< 30×10⁹/L despite treatment with standard-dose corticosteroids for ≥ 4 weeks; relapse: platelet count drops again to \< 30×10⁹/L after corticosteroid dose reduction or discontinuation). 4. Sustained platelet count \< 30×10⁹/L during the screening period. 5. Subjects voluntarily participate in this study and sign a written informed consent form. Exclusion Criteria: 1. Secondary thrombocytopenia caused by other factors, such as drug-induced etiology, infection-related conditions, or other autoimmune diseases (e.g., systemic lupus erythematosus). 2. Subjects positive for Helicobacter pylori (H. pylori) infection (rescreening is permitted only after completion of standard eradication therapy and a drug withdrawal period of at least 1 month). 3. Active infection or receipt of systemic antibiotic therapy within the past 4 weeks. 4. Severe cardiac, hepatic, or renal insufficiency (e.g., Child-Pugh Class C liver dysfunction, or estimated glomerular filtration rate \< 30 mL/min/1.73 m²). 5. A history of malignant tumors or primary immunodeficiency diseases. 6. Pregnant or lactating women. 7. Previous splenectomy, rituximab therapy, or plasma exchange treatment within the past 3 months. 8. Other conditions deemed inappropriate for study participation by the investigators based on clinical judgment.