Therapy of type 1 diabetes with CD4+CD25highCD127-regulatory T cells prolongs survival of pancreatic islets - Results of one year follow-up

•This study shows first-in-man treatment of type 1 diabetes with T regulatory cells.•It has been found that repetitive administration of Tregs in DM1 children is safe.•The administration of Tregs prolonged survival of β cells in DM1 patients.

It is hypothesized that CD4+CD25+FoxP3+ regulatory T cells (Tregs) can prevent destruction of pancreatic islets protecting from type 1 diabetes (DM1).Here we present results of one year follow-up of 12 DM1 children treated with autologous expanded ex vivo Tregs. Patients received either a single or double Tregs infusion up to the total dose of 30 × 106/kg.No severe adverse effects were observed. The treatment did not impair post-immunization antibody responses. Tregs infusion was followed by increase in Tregs number in peripheral blood. Most of the patients responded to the therapy with increase in C-peptide levels (8/12 and 4/6 after the first and the second dose, respectively). Tregs administration resulted also in lower requirement for exogenous insulin (8/12 treated patients versus 2/10 untreated controls in remission) with two children completely insulin independent at one year. Repetitive administration of Tregs is safe and can prolong survival of β-cells in DM1 (registration: ISRCTN06128462).