**3. Cellular therapy of type 1 diabetes**

T1D is characterized by the autoimmune destruction of insulin-producing β cells with loss of insulin secretion. Patients with T1D have absolute requirement of insulin for survival. While insulin is effective in lowering blood glucose, hypoglycemia, even life-threatening hy‐ poglycemia, is almost unavoidable with insulin treatment, as exogenous insulin cannot ex‐ actly mimic the profile of physiological insulin secretion. Other limitations of insulin therapy include inconvenience of daily life, physical pain and high economic costs caused by recurrent insulin injections.

Therefore, other strategies have been explored to preserve or restore β cell function in the hope that endogenous insulin secretion will achieve better glycaemic control while reducing episodes of severe hypoglycemia. As discussed above, immunotherapy, in particular the use of immunomodulatory drugs has pulled much efforts. Both experimental and clinical data demonstrate that some agents like anti-CD20 and anti-CD3 antibodies are effective in delay‐ ing the process of β cell autoimmune destruction. However, no drugs have demonstrated to prevent or reverse human T1D successfully in long-term.

More recently, many efforts have been focused on the use of stem cells as a potential thera‐ peutic strategy for T1D. So far, accumulating data from both experimental and clinical trials have suggested that stem cell-based cellular therapy could be a promising approach for T1D treatment.
