The main goal is to perform a cost-utility analysis to compare islet cell transplantation versus best medical treatment (defined as Sensor augmented pump therapy) for patients with brittle type1 diabetes.

The main goal is to perform a cost-utility analysis to compare islet cell transplantation versus best medical treatment (defined as Sensor augmented insulin pump therapy) for patients with brittle type1 diabetes.

Inclusion Criteria :

• Suffering from diabetes since more than 5 years
• Patient with brittle type 1 diabetes despite an optimized insulin treatment and educational training will be included. A patient will be considered as experiencing a brittle type 1 diabetes if at least two criteria are present among: persistence of severe hypoglycemia, occurrence of ketoacidosis events without obvious etiology, diagnosis of unaware hypoglycemic episodes < 3 mmol/l based on CGM or self-monitoring blood glucose data, a mean blood glucose standard deviation>50%, MAGE index (Mean amplitude of glucose excursions)>60 mg/dl, LBGI index (low blood glucose index)>5, Clarke score≥4 or HYPOSCORE>800.
• Insulin needs < 0,85 U/kg/day
• HbA1c < 12% ;
• No residual insulin secretion (plasmatic basal and stimulated C-peptide < 0.3 ng/ml)
• Social Security membership or benefit from Social Security
• Patients who signed the consent form

Exclusion Criteria :

Exclusion criteria related to islet infusion:

• Hemostatic disorders, pre-existing liver disease (PAL, Gamma-GT, ASAT-ALAT >2N) or vesicular lithiasis.

Exclusion criteria related to diabetic complications:

• Evolutive proliferative retinopathy, evolutive nephropathy (Glomerular filtration rate <30 ml/min/1.73m2 and/or proteinuria >0.5g/day), evolutive cardiopathy or obliterative arteriopathy with trophic cutaneous lesions.

Exclusion criteria related to immunosuppressant use:

• Hemoglobin < 110mg/dL in women and < 120 mg/dL in men, leuconeutropenia, thrombopenia, systemic infection including chronic hepatitis B, C and VIH, neoplasia disease and hypertension>160/100 mmHg.
• Corticoid treatment (except for patient that benefited from a kidney graft with maintenance steroid therapy)
• Presence of anti-HLA antibody directed against the donor
• Positive B or T cells crossmatch