Safety and Efficacy of Umbilical Cord Blood Regulatory T Cells Plus Liraglutide on Autoimmune Diabetes

Inclusion Criteria: * Type 1 diabetes according to ADA criteria \<3 years. * Age≥ 18 years. * Positive for at least one of the anti-islet autoantibodies: GADA, IA2A, ZnT8A * Fasting or postprandial plasma C-peptide more than 100 pmol/L * Written informed consent from the patient or family representative. Exclusion Criteria: * History or family history of medullary thyroid carcinoma or MEN 2 syndrome; * History of chronic or acute pancreatitis; * Allergic to liraglutide or any components in Victoza®; * Hepatic abnormalities (transaminase \> 2 times normal); * Renal impairments (serum creatinine \>133 umol/L); * Cardiovascular diseases (hypertension, coronary heart disease, etc.); * Presence of anemia (Hb ≤100g/L), leukopenia (\<3.5×109/L); * Presence of disorder in coagulation or anticoagulation, or thrombocytopenia (platelets \<100×109/L); * Presence of acute metabolic disorders; In the case of acute ketone acidosis, with blood ketone over 0.3mmol/L and pH lower than 7.30; * Presence of any kind of chronic infection or immune deficiency, including hepatitis B, hepatitis C, HIV, syphilis or tuberculosis, etc.; * Chronic use of systemic glucocorticoids or other immunosuppressive agents for over 3 months; * Any history of malignancy; * Female patients who are pregnant or breastfeeding; any female who is unwilling to use a reliable and effective form of contraception for 2 years after recruitment; * Presence of any infectious diseases, including active skin infections, flu, fever, upper or lower respiratory tract infections; those who wish to participate in the study should keep the infection under control for at least 1 week before receiving Treg product infusion; * Any medical condition that, in the opinion of the investigator, will interfere with safe participation in the trial.