Crosstalk Between Mucosal-Associated Invariant T (MAIT) Cells and the Gut Microbiota and Mucosa in the Development of Type 1 Diabetes in Children

To investigate in a prospective way changes in Mucosal-Associated Invariant T (MAIT) cells frequency, phenotype and function in link with the gut microbiota, gut integrity and the presence of Coxsackie virus B in two cohorts of pediatric patients: patients with a high genetic risk of type 1 diabetes and pediatric patients with recently diagnosed T1D by comparison with control subjects Tasks: 1. To measure blood MAIT cells frequency, phenotype and function in the three cohorts 2. To analyze gut microbiota and the presence of Coxsackie B enterovirus (CVB) and their impact on MAIT cell function 3. To evaluate gut integrity and analyze the gut mucosa 4. To integrate all the data obtained with T1D development and evolution

Inclusion Criteria: Recent onset group * age \> 12 months and \< 15 years * recently diagnosed type 1 diabetes according ISPAD criteria At risk subjects: * age \> 12 months and \< 15 years * siblings of type 1 diabetic patient * HLA DR3 and DR4 positive Control subjects: * age \> 12 months and \< 15 years * no HLA associated with high risk type 1 diabetes * no antibodies against pancreas antigenes Control subjects for UGI endoscopy: * age \> 12 months and \< 15 years * suspicion of coeliac disease or gastritis Exclusion Criteria: For all groups: * no health care insurance * parents or tutors unable to sign the consent * personal history of autoimmune disease and/or inflammatory disease except from T1D for RD and CE groups * use of corticosteroids during the month before inclusion * pregnant subjects * medical contraindication of anesthetic topics For control subjects for UGI endoscopy control and Recent onset-endoscopy group: * age below 8 years for Recent onset-endoscopy group * age below 4 for UGI endoscopy control group * cardiac or respiratory insufficiency, cardiac rhythm disorders, coagulation disease, patients treated with anticoagulant or antiaggregant drug * history of allergy to anesthetic drug