The purpose of this study is to evaluate the safety and efficacy of mesenchymal stem cells (MSCs) derived from human umbilical cord/placenta at a dose of 1.0E+6 MSC/kg on the subjects for refractory anemia (RA) and refractory anemia with ring sideroblast (RARS) of myelodysplastic syndromes (MDS).

Myelodysplastic syndromes are bone marrow stem cell disorders resulting in disorderly and ineffective hematopoiesis. MDS is characterized by variable degrees of cytopenias (anemia, neutropenia, and thrombocytopenia ) and risk of transformation to leukemia.

To date treatment of MDS is unsatisfactory: chemotherapy has a limited role in the management of leukemic progression; autologous stem cell transplantation does not prolong relapse-free survival and stem cell transplantation is poorly tolerated in older individuals. Some MDS patients have been shown to respond to a wide variety of immunosuppressive agents ranging from corticosteroids to CsA and antithymocyte globulin (ATG). However, the overall response rate is less than 30%. In fact, few treatments appear to change the natural history of MDS.

The management of MDS patients therefore remains to be improved. Human MSCs isolated from Wharton's jelly of the umbilical cord/placenta have been shown to have immunosuppressive, stimulating hematopoiesis and tissue repairing properties. This study will evaluate the safety and effectiveness of MSC transplant in the MDS patients.

This study will last about 3 years. Participants will be randomly assigned to receive either MSC transplant (Group 1) or CsA therapy alone (Group 2). Patients will undergo MSC transplant at the start of the study (defined as Day 0). After 3 months, patients will receive the second MSC transplantation when one responds well to the treatment. After 3, 6 and 12 months from the first transplantation, patients will be evaluated.

Inclusion Criteria:

1. Patient age 18~80 years old with plan to infuse MSCs.
2. Histologically documented or cytologically confirmed diagnosis of MDS with WHO classification of MDS-RA and MDS-RARS.
3. Patients must have an ECOG 0~2.
4. No moderate or sever organ dysfunction: Ejection fraction>45%; Creatinine <176 mmol/L.
5. No active severe viral or fungus infection.
6. Each patient must sign written informed consent.

Exclusion Criteria:

1. Psychiatric condition that would limit informed consent.
2. HIV positive
3. Positive Pregnancy Test
4. Patient has enrolled another clinical trial study within last 4 weeks.