Lymphocytic insulitis in a juvenile dog with diabetes mellitus

• Published in: Endocrine pathology 2006, Vol.17 (3), p.283-290
• Main Authors: Jouvion, G, Abadie, J, Bach, J M, Roux, F, Miclard, J, Deschamps, J Y, Guigand, L, Saï, P, Wyers, M
• Format: Article
• Language: English
• Subjects: Animals; Diabetes; Diabetes Mellitus - pathology; Diabetes Mellitus - veterinary; Dogs; Hyperglycemia - etiology; Immunohistochemistry; Inflammation - immunology; Inflammation - pathology; Insulin-Secreting Cells - pathology; Pancreas; T-Lymphocytes - immunology
• ISSN: 1046-3976; 1046-3976; 1559-0097
• DOI: 10.1385/EP:17:3:283

Autoimmune diabetes has never been described in a juvenile dog, whereas serological evidence has established its development in adult dogs. Diabetes mellitus was diagnosed in a 3-mo-old Donge de Bordeaux dog suffering from persistent hyperglycemia and concurrent insulinopenia. Histological analysis of the pancreas revealed inflammatory lesions in 40% of the islets of Langerhans, with infiltration predominantly by T lymphocytes (more than 90%), either at the edge (peri-insulitis: 10%) or in the islets (insulitis: 30%). The remaining 60% of the islets showed a marked atrophy due to massive beta cell loss with no loss of alpha cells. This pattern is quite similar to that observed in humans in which a characteristic insulitis containing high numbers of T lymphocytes is found in 20% of the islets at diabetes diagnosis. By contrast, in rodent models, nearly 70% of the islets of Langerhans show inflammation at diagnosis and macrophages and dendritic cells predominate in the inflammatory lesions. This is the first report of lymphocytic insulitis in a juvenile dog exhibiting diabetes mellitus. Our observations suggest an autoimmune origin for the disease in this dog that is similar to human type 1 diabetes mellitus, for which there is no accurate spontaneous large animal model.