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.
- © 2014 by the American Diabetes Association.
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