Lymphocytic insulitis in a juvenile dog with diabetes mellitus

Endocr Pathol. Fall 2006;17(3):283-90. 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.

MeSH terms

  • Animals
  • Diabetes Mellitus / pathology*
  • Diabetes Mellitus / veterinary*
  • Dogs
  • Hyperglycemia / etiology
  • Immunohistochemistry
  • Inflammation / immunology
  • Inflammation / pathology
  • Insulin-Secreting Cells / pathology*
  • T-Lymphocytes / immunology