Our project “Linking IHC profiles of duodenum and pancreas in T1D” aims to intensify our understanding of how the “gut immune system” contributes to the development of type 1 diabetes.

Previous studies have shown that factors like the gut microbiome, gut permeability and the mucosal structure play a role in T1D pathogenesis. Studies are now more and more focusing on intestinal immune cells and their contribution to the onset and disease course of T1D. Regulatory T cells (Tregs) are of special interest in this regard, since they are capable of suppressing auto-reactive effector T cells, and thereby prevent autoimmune reactions. The role of intestinal Tregs in T1D development has been described controversially. While some papers report of increased numbers of Tregs in the intestine of T1D patients, other publications find no difference in Treg numbers between patients and healthy subjects. With our new immunohistochemical method, which allows us the identification of CD4+CD25+FoxP3+ putative regulatory T cells with a specificity that has not been reached before, we hope to shed light on regulatory T cell profiles of duodenum and pancreas in parallel in patients at different disease stages compared to healthy subjects. Additionally we aim to investigate CD8+ and CD4+ Th17 effector T cells in the same tissues in order to get comprehensive information on regulatory and effector T cell subsets. Furthermore, we will investigate T cell function by using single-cell analysis of positively stained T cells regarding their expression profiles and methylation status.

Thus, using the precious nPOD samples, we hope to identify immunological processes in the duodenum and pancreas that play a crucial role in the development and pathogenesis of type 1 diabetes.