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 in subject for the therapy of Ankylosing spondylitis (AS)

Ankylosing spondylitis (AS) is a chronic, progressive inflammatory rheumatic disease involving primarily the sacroiliac joints and the axial skeleton. The main clinical features are back pain and progressive stiffness of the spine. Oligoarthritis of the hips and shoulders, enthesopathy, and anterior uveitis are common, and involvement of the heart and lungs is rare. The current understanding of the pathogenesis of this disorder is limited.It mainly about to hereditary susceptibility (eg hla-b27),infection and autoimmunity.

Although traditional drugs, such as Nonsteroidal antiinflammatory drugs (NSAIDs) disease-modifying antirheumatic drugs (DMARDs such as MTX,SASP OR thalidomide) and steroids have been used in the treatment of AS, however, many studies have indicated that the overall response to these drugs is not satisfied. Addition, the severe side effects of these drugs have also been observed. The management of AS patients therefore remains unsatisfactory and targeted therapies are needed. Human MSCs isolated from human umbilical cord/placenta have been shown to have immunoregulatory, immunosuppressive, stimulating hematopoiesis and tissue repairing properties. This study will evaluate the safety and effectiveness of MSC transplantation in the AS patients.

This study will last 2 to 3 years. Participants will be randomly assigned to receive either MSC transplant +DMARDs therapy (experimental group) or DMARDs therapy (control group). Patients will undergo MSC transplant at the start of the study on Day 0. After 3 months, patients will receive the second MSC transplantation. After six and twelve months from the first transplantation, patients will be evaluated.

Inclusion Criteria:

1. Patient age 18~60 years old with plan to infuse MSCs.
2. Diagnosis of "Definite AS" (arthritis of the spine) as defined by the modified New York criteria
3. Stable doses of sulfasalazine,methotrexate,thalidomide,hydroxychloroquine, low-dose corticosteroids, and NSAIDs are permitted
4. Patients must have an ECOG 0~2.
5. No moderate or sever organ dysfunction: Ejection fraction>45%; Creatinine <176 umol/L.
6. No severe infection.
7. Each patient must sign written informed consent.

Exclusion Criteria:

1. Other serious concomitant diseases (uncontrolled/severe kidney, liver, haematological, gastrointestinal, endocrine, cardiovascular, pulmonary, neurological or cerebral disease)
2. Psychiatric condition that would limit informed consent.
3. HIV, hepatitis B or C, tuberculosis, other infections
4. Positive Pregnancy Test or lactation
5. Patient has enrolled another clinical trial study within last 4 weeks.
6. Contraindications to MSC