Islet Transplantation With Recipient T-Reg Cells or Deceased Donor Vertebral Bone Marrow Therapy

The goal of this clinical trial is to learn if patients who have brittle type 1 diabetes receiving an islet transplantation will have better control of their sugars if they also receive one of 2 types of immune cells along with the islet transplant. The participants will receive either their own immune cells, called regulatory T cells, or immune cells from the bone marrow of the islet donor.