Natural Killer Cells Infusion for Treating Acute Myeloid Leukemia Patients With Minimal Residual Disease

Inclusion Criteria: 1. Patients diagnosed with acute myeloid leukemia; 2. MRD after 2 course of standard chemotherapy; 3. No plan for hematopoietic stem cell transplantation; 4. Hemoglobin (Hb) \>=60g/L, white blood cell count (WBC) \>=2.5x10\^9/L, platelet count \>=30x10\^9/L; 5. Patients have self-knowledge ability and can sign informed and voluntary consent forms; 6. Patients or their clients, guardians of pediatric patients signed the informed and voluntary consent form and joined the study. Exclusion Criteria: 1. Intracranial hypertension or unconsciousness; 2. Symptomatic heart failure or severe arrhythmia; 3. Respiratory failure; 4. With other types of malignant tumor diseases; 5. T lymphocytic acute leukemia; 6. Diffuse intravascular; 7. Serum creatinine and / or urea nitrogen \>=1.5 times the normal value;coagulation; 8. Serum total bilirubin \>=1.5 times the normal value; 9. Sepsis or other difficult-to-control infections; 10. Uncontrollable diabetes; 11. severe mental disorders; 12. WHO physical status classification \>=3; 13. People who are allergic to Interleukin-2; 14. Patients after organ transplant; 15. Pregnant and lactating women.