Type 1 diabetes is an autoimmune disease and results from T cell autoimmunity mediated destruction of the majority of insulin-producing pancreatic β-cells. Hence,the development of new therapies to control T cell autoimmunity, and to preserve the remaining β-cell function will be of great significance in managing patients with type 1 diabetes

Autologous nonmyeloablative hematopoietic stem cell transplantation (AHST) has been tested for the treatment of patients with new onset of type 1 diabetes. This therapeutic strategy can result in exogenous insulin independence by destroying pathogenic memory T cells and preserving the remaining β-cell function.

However, little is known about the efficacy of AHST in the dynamics of immunocompetent cell reconstitution and how the reconstituted immune system regulates β-cell specific antibody response. Furthermore, many Chinese patients at diagnosis of type 1 diabetes have progressed to develop diabetic ketoacidosis (DKA). Whether treatment with AHST could still achieve adequate glycemic control and preserve the β-cell function and what the factors are associated with the therapeutic efficacy have not been explored.

This is a phase Ⅱ clinical trial in patients who have been diagnosed with type 1 diabetes within the previous 12 months.This study is to determine:

• The effects of autologous hematopoietic stem cell transplantation on the reconstitution of immune system
• β-cell preservation following stem cell transplantation
• The potential factors affecting efficacy of stem cell transplantation
• Whether this new therapy is safe.

Patients diagnosed with type 1 diabetes within the previous 12 months will be recruited into this study.Hematopoietic stem cells were mobilized with cyclophosphamide (CY, 2.0g/m2) and granulocyte colony stimulating factor (10 μg/kg per day) and then collected from peripheral blood by leukapheresis and cryopreserved. The cells were infused after conditioning with CY (200 mg/kg) and rabbit antithymocyte globulin (4.5 mg/kg). All the included patients undergoing AHST complied with blood glucose self-monitoring and scheduled medical appointments.Their blood samples were obtained for measuring the frequency of lymphocytes and the levels of plasma hemoglobin A1c (HbA1c), serum C-peptide, islet antibodies, and cytokines longitudinally.

Ages Eligible for Study: no more than 35 years

Genders Eligible for Study: both

Islet Autoantibodies Eligible for Study: positive for glutamic acid decarboxylase antibody (GADA), protein tyrosine phosphatase antibody (IA-2A), islet cell antibody (ICA) and/or insulin autoantibody (IAAs)

Inclusion Criteria:

• diagnosis of diabetes according to the guidelines of the World Health Organization 1999
• the duration of diabetes is no more than 12 months
• positive for for glutamic acid decarboxylase antibody (GADA), protein tyrosine phosphatase antibody (IA-2A), islet cell antibody (ICA) and/or insulin autoantibody (IAAs)

Exclusion Criteria:

• pregnancy
• mental disorders
• blood diseases
• the presence of any other severe diseases that could potentially influence the transplantation outcomes