Cohort Study to Refine the Positioning of Closed-loop Therapy Versus Islet Transplantation in the Management of Patients With Unstable Type 1 Diabetes

Inclusion Criteria: Type 1 diabetic patients describing: * Significant glycaemic variability defined by the presence of one of these 3 criteria: - Standard deviation \> 50% of the glycaemic mean or a MAGE index \> 60 mg/dL * Coefficient of glycaemic variation \> 36% * LBGI index \> 5 or HYPOSCORE \> 800 * This glycaemic variability must be persistent, i.e. persist for more than 12 months despite optimal diabetes management by a multi-professional team. Optimum management involves : * Monitoring by a team with expertise in insulin pump and glucose sensor technologies * Training patients in functional insulin therapy, intensive self-monitoring of blood glucose levels, and prevention and management of situations where there is a risk of hypoglycaemia * Use of pump and glucose sensor therapy, with interruption before hypoglycaemia * Reinforced multi-professional support and monitoring, possibly combined with support via telemedicine. * This glycaemic variability must be considered as severe, i.e. causing unpredictable clinical and metabolic events that impair quality of life, such as severe, disabling and frequent hypoglycaemia (at least 2 Severe Hypoglycaemia with assistance from a third party in the last 12 months or at least 1 Severe Hypoglycaemia with life-threatening consequences in the last 12 months (coma, convulsions or trauma)) or ketosis ketoacidosis. Exclusion Criteria: * Patients with type 1 diabetes who do not meet the criteria for islet transplantation * Patients already fitted with a closed loop * Kidney transplant patients * Persons covered by articles L1121-5 to L1121-8 of the CSP (corresponding to all protected persons) * Persons opposed to participation in research