PolyTreg Immunotherapy in Islet Transplantation

Islet transplantation is a relatively new procedure used in people with difficult to control Type 1 diabetes. Patients who receive an islet transplant take medication that suppresses their immune system and prevent rejection of the islet tissue. In spite of the strengths of the current immunosuppression regimen, it has failed to enhance single-donor success rates, and the majority of patients require 2 or more islet transplants to achieve insulin independence. The need for life-long, high-dose immunosuppression is also associated with substantial side effects, and continues to limit application of islet transplantation earlier in the course of the disease. The investigators have learned that Regulatory T cells (Tregs), a small subset of cluster of differentiation 4+ (CD4+) T cells, have emerged as the major contributor to self-tolerance through suppression of activation and effector function of other immune cells. Tregs function by preventing the initiation of unwanted immune activation and by suppressing ongoing immune response to limit bystander tissue destruction. It has been suggested that infusion of Tregs before extensive graft damage may improve long-term graft outcomes. This study is an open label, controlled, dose finding pilot study. Up to 18 participants will be recruited including 12 participants receiving the investigational treatment and 6 participants being assigned to control group. All participants will undergo the routine Standard of Care islet transplant procedure, and will be maintained on lower dose tacrolimus and sirolimus immunosuppression. The primary goal is to assess the safety and feasibility of intravenous infusion of ex vivo-selected and ex vivo-expanded autologous PolyTregs in islet transplant patients. The other goal is to assess the effect of Tregs on beta cell function in islet transplant patients. The control group (6) will receive the current Edmonton islet transplant induction therapy (Alemtuzumab with Etanercept and Anakinra)