Increased immune cell infiltration of the exocrine pancreas: a possible contribution to the pathogenesis of type 1 diabetes

  1. Matthias G. von Herrath1,4
  1. 1Type 1 Diabetes Center, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
  2. 2Departments of Rheumatology and Pediatrics at the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
  3. 3Freelance consultant, San Diego, California, USA
  4. 4Novo Nordisk Diabetes Research & Development Center, Seattle, Washington, USA
  1. Corresponding author: Matthias G. von Herrath; Email: matthias{at}liai.org; mtvh{at}novonordisk.com

Abstract

Type 1 diabetes (T1D) results from a complex interplay between genetic susceptibility and environmental factors which have been implicated in the pathogenesis of disease both as triggers and potentiators of beta cell destruction. CD8 T cells are the main cell type found in human islets and they have been shown in vitro to be capable of killing beta-cells over-expressing MHC class I. Here we report that CD8 T cells infiltrate the exocrine pancreas of diabetic subjects in high numbers, and not only endocrine areas. T1D subjects present significantly higher CD8 T cell density in the exocrine tissue without the presence of prominent insulitis. Even T1D donors without remaining insulin containing islets (ICIs) and long disease duration show elevated levels of CD8 T cells in the exocrine compartment. In addition, higher numbers of CD4+ and CD11c+ cells were found in the exocrine tissue. Preliminary data in T2D subjects indicates that overall, there might be a spontaneous inflammatory infiltration of the exocrine tissue, common to both T1D and T2D subjects. Our study provides the first information on the precise tissue distribution of CD8 T cells in pancreata from T1D, T2D, Ab+ and healthy controls.

  • Received April 4, 2014.
  • Accepted June 13, 2014.

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