EBV-AST Cell Therapy for EBV-Related Diseases After Stem Cell Transplantation

Inclusion Criteria: 1. The patient must be aged 18-75 years. 2. ust have undergone Allogeneic Hematopoietic Stem Cell Transplantation (Allo-HSCT). 3. Must have EBV-DNA viremia post-transplant, with EBV-DNA \> 1000 copies/mL (on two consecutive tests or one test \> 10,000 copies/mL). 4. Karnofsky Performance Score (KPS) of 70 or higher. 5. Expected survival of at least 3 months. 6. Sufficient organ function, including renal (serum creatinine ≤ 1.5 × ULN and creatinine clearance ≥ 50 mL/min), hepatic (AST, ALT, and total bilirubin ≤ 5 × ULN), and hematologic parameters (platelets ≥ 10 × 10\^9/L, neutrophils ≥ 1.0 × 10\^9/L). 7. HLA-matching criteria must be met for the donor/recipient. Exclusion Criteria: 1. Active GVHD (Grade 2 or higher) or requiring \>0.5 mg/kg/day corticosteroids for GVHD. 2. History of CMV viremia or disease within the past week. 3. PTLD (Post-Transplant Lymphoproliferative Disorder) diagnosed or suspected within 1 week before infusion. 4. Severe active infections (excluding EBV and CMV). 5. Serious allergic reactions or contraindications to the infusion. 6. Previous immune therapy-related adverse events of Grade 3 or higher. 7. History of HIV, HCV, or HBV infection with an active viral load.