Inclusion Criteria:  Type 1 diabetes: type 1 diabetes, as defined by hyperglycemia and long-term insulin therapy started within 6 months from clinical onset; and/or the presence of at least one anti-islet auto-antibody. Other forms of diabetes or autoimmune endocrinopathy: other forms of diabetes (e.g. type 2, ketosis-prone, familial, secondary, immunotherapy-induced diabetes); and/or other autoimmune endocrinopathies, isolated or multiple. No diabetes: absence of diabetes or impaired glucose tolerance; absence of tumor, infectious or immune pathologies, or other conditions related to autoimmune or metabolic alterations that may bias the variables under study. Lymphadenectomy planned in the frame of an abdominal surgery: pancreatic lymphadenectomy planned at the occasion of an abdominal surgery for the treatment of an underlying condition.  Exclusion Criteria:  For all participants: ongoing pregnancy; known HIV/HCV infection; absence of social security coverage; placement under judicial protection; absence of signature of the informed study consent.