Clinical trials started in 2005, USA. Children with I type diabetes were treated with their cord blood stem cells. Trial results showed health improvements. Stem cells stimulated immune system and reduced destruction  of cells who generates insulin. 6 months after transplantation children's health was much better. Next clinical trial stated in Germany. In 2010 there were 23 cases of such treatment. 

Source: Haller MJ, et al., Nov 2009, Diabetes Care 32(11):2041-6