In Vivo Imaging of the Innate Immune System in the Pancreas in New-Onset and Long-Standing Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease, but knowledge of immune cell infiltration in the human pancreas is limited due to the risks associated with pancreatic biopsies. This study aimed to evaluate the feasibility of imaging innate immune cells in vivo using positron emission tomography (PET).

We used PET tracers targeting M1 macrophages ([⁶⁸Ga]-DOTATATE) and neutrophil elastase ([¹¹C]-NES) to assess pancreatic immune cell infiltration in individuals with new-onset T1D (n = 4), long-standing T1D (n = 6), and healthy controls (n = 6).

Both tracers enabled visualisation and quantification of pancreatic uptake. Uptake of both [⁶⁸Ga]-DOTATATE and [11C]-NES was not increased in new-onset T1D compared to healthy controls but was elevated in individuals with long-standing T1D.

PET imaging of innate immune cells in the pancreas is feasible. While no increased macrophage or neutrophil activity was observed in new-onset T1D, increased tracer uptake in long-standing T1D may reflect late-stage inflammatory processes and fibrosis.