This is a phase II trial in individuals who have been diagnosed with type 1 diabetes within the previous 12 months and suffered from diabetic ketoacidosis at onset of disease. The purpose of this study is to determine whether allogeneic umbilical cord mesenchymal stem cell transplantation is effective in the treatment of patients with severe type 1 diabetes.

To assess the clinical efficacy of allogeneic umbilical cord mesenchymal stem cell transplantation in the treatment of patients with severe type 1 diabetes, defined as with the history of diabetic ketoacidosis from diagnosis. All the patients are intravenously administrated with single-dose or double-dose umbilical cord mesenchymal stem cell and followed up for 36 months. Clinical and laboratory manifestations are compared before and after transplantation.

Inclusion Criteria:

• Type 1 diabetes
• Duration of disease less than 12 months from diagnosis
• With the history of diabetic ketoacidosis

Exclusion Criteria:

• Pregnancy
• Severe psychiatric disorder
• Severe organic impairment(renal,hepatic,cardiac,pulmonary)
• Active infectious disease
• Previous or present neoplastic disease