NK Cell Therapy Recurrent/Refractory Elderly AML

Inclusion Criteria: 1. The 2 or more than 2-cycles of standard regimen was used to treat elderly AML patients who did not achieve complete remission or relapse. 2. Patients with age 60 years to 70 years. 3. KPS greater than or equal to 60. 4. ALT and AST are less than 3 times normal. 5. Total bilirubin less than 1.5mg/dl(25.65umol/L). 6. Serum creatinine less than 2.5mg/dl(221umol/L), or creatinine scavenging ability greater than or equal to 60 mL/min/1.73 m2. 7. Left ventricular ejection fraction cardiac greater than or equal to 45%, Echocardiography (ECHO) showed no pericardial effusion, Electrocardiogram (ECG) is normal. 8. No pleural effusion in lungs 9. Oxyhemoglobin saturation greater than or equal to 92% in normal environment. 10. KIR mismatch between patient and umbilical cord blood. 11. Volunteer to participate in the trial and sign the informed consent form. Exclusion Criteria: 1. Malignant tumor patient. 2. Patients who are accompanied by fungal, bacterial, viral, or other uncontrolled infections or require level 4 isolation( HBV-DNA quantification and normal liver function in patients with hepatitis b infection are excluded). 3. Patients with HIV, HCV positive. 4. Patients with central nervous system diseases, including stroke, epilepsy, dementia, or autoimmune central nervous system disorders. 5. During the first 12 months of enrollment, patients with cardioangiography or stents, active angina pectoris or other clinically significant symptoms, or with cardiogenic asthma. 6. Patients receiving anticoagulant therapy or with severe coagulation disorders. 7. According to the researcher's judgment, the drug treatment the patient is receiving will affect the safety and effectiveness of the study. 8. Patients with allergies or history of allergies to biological agents used in this program. 9. Systemic steroid used within 2 weeks before treatment (except for recent or present use of inhaled corticosteroids). 10. Patients with other uncontrolled diseases, Investigators think it is not suitable for the participants. 11. Any circumstance that the investigator considers may increase the risk to the subject or interfere with the results of the study. 12. Patients participate in other clinical studies.