Cell Therapy with Anti-CD19 CAR-NK Cells in Patients with Relapsed or Resistant B-ALL

Ten eligible patients with relapsed Acute Lymphoblastic Leukemia will be enrolled based on inclusion criteria and informed consent. After conditioning with Fludarabine and Cyclophosphamide, patients will receive a single infusion of anti-CD19 CAR NK cells with close monitoring using one of the following dose levels: • Dose Level 1: 1×10\^7/Kg • Dose Level 2: 5×10\^7/Kg • Dose Level 3: 1×10\^8/Kg Safety Assessment: Adverse events will be recorded and graded. Laboratory parameters and cytokine release syndrome (CRS) markers will be closely monitored. Efficacy Evaluation: Response assessments will follow International Lymphoma Party (LWP) Group guidelines, including complete response (CR), partial response (PR), stable disease (SD), and progressive disease.