The aim of this investigation was to assess safety and efficacy of allogenic NK cells therapy for refractory MDS-EB.

Inclusion Criteria:

1. Patients with refractory high-risk MDS (MDS-EB1 and EB2) who had no effect of 2 courses of desitabine or CAG or desitabine + CAG.
2. Patients with age 15 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. Women of child-bearing age have negative urine pregnancy tests before administration began, and agree to use effective contraception during the trial period up to the last follow-up.
11. KIR mismatch between patient and umbilical cord blood.
12. 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. Patients with central nervous system diseases, including stroke, epilepsy, dementia, or autoimmune central nervous system disorders.
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. Lactating or pregnant women.
10. Systemic steroid used within 2 weeks before treatment (except for recent or present use of inhaled corticosteroids).
11. Patients with other uncontrolled diseases, Investigators think it is not suitable for the participants.
12. Any circumstance that the investigator considers may increase the risk to the subject or interfere with the results of the study.
13. Patients participate in other clinical studies.