T1DM Immunotherapy Using Polyclonal Tregs + IL-2

The investigators hypothesize that ex vivo expanded human autologous CD4+CD127lo/-CD25+ polyclonal regulatory T cells (Polyclonal Tregs) plus Interleukin-2 (IL-2) administered to patients with Type 1 Diabetes Mellitus (T1DM) will be safe and biologically active. A Phase I trial with this cellular therapy plus IL-2 will lead the way for Phase II trials that test for efficacy based on preservation of C-peptide, reduced exogenous insulin requirements and improved glycemic control. This is a Phase I safety/dosing study of Polyclonal Tregs + IL-2 in patients with T1DM. The Tregs will be expanded using an established protocol utilizing anti-CD3/anti-CD28 beads plus IL-2. The study will involve 2 dosing cohorts of 6-8 T1DM patients each. The primary objective of this study is to assess the safety of Tregs + IL-2 and survival of Tregs in patients with recent onset T1DM who receive infusions of autologous Tregs + IL-2. The study will also assess potential effects of Tregs on beta cell function and the autoimmune response. Subjects will receive Polyclonal Tregs at doses of 3 or 20x10\^6 cells/kg. The dose of Tregs is selected based on a combination of considerations of manufacturing capacity, a predicted efficacious dose, and the available safety data of the Treg product currently in clinical trials. The IL-2 dose will be 1 x10\^6 IU subcutaneously, given daily for 5 consecutive days at the completion of the cell infusion and again after 1 month. This dose is based on recent studies from Klatzmann et al. in T1DM, where the dose was found to be effective in a selective Treg expansion, well tolerated, and without an acute decline in beta cell function (Rosenzwajg et al., 2015).