Islet Transplantation Alone (ITA) in Patients With Difficult to Control Type I Diabetes Mellitus Using a Glucocorticoid-free Immunosuppressive Regimen

Inclusion Criteria: * Difficult to control Type 1 diabetes mellitus (defined above). Documentation of negative basal and stimulated C-peptide (a basal level of \< 0.2 ng/ml before IV administration of 1 mg of glucagon, and a glucagon stimulated C-peptide \< 0.8 ng/ml) and diagnosis of diabetes for at least 5 years. When possible, patients will be evaluated with continuous glucose monitoring (GlucoseSensor ®) to determine the frequency and extent of hypo- and hyperglycemic episodes. * No evidence of chronic renal failure or significant proteinuria (serum creatinine \< 1.6 mg/dl, creatinine clearance \>80 ml/min, and albumin excretion \</= 300 mg/24 hr). * No evidence of liver disease (liver enzymes \< twice the upper limit of normal for each of ALT and AST, bilirubin \< 2 mg/dl, albumin \> 3.5 g/dl, and PT and PTT \</= 1.1 x the upper limit of normal). * Frequent episodes of symptomatic hypoglycemia (i.e. loss of consciousness, headaches, anxiety, irritability, trembling, sweating) more than once per week, documented hypoglycemic unawareness (i.e. no adrenergic and/or neurogenic symptoms with blood glucose \< 54 mg/dl) two or more times in the past two months, or hypoglycemic episodes that required the assistance of another person more than once per month or hospitalization more than once over the past 20 months. * Ability to comply with post-transplant regimen, including immunosuppression, insulin pump therapy and metabolic testing. Patients will be required to perform self-…