Figure 2.

Proposed models of islet-specific T cell detection in the blood. While pancreatic islets contain a certain amount of T cells regardless of disease status (gray bars), only islets of individuals with T1D contain T cells that are highly reactive to islet antigens (red bar). Model (A) Leak of T cells from the islets to peripheral blood is limited. T cell repertoires specific to islet antigens are not different between individuals with and without T1D. Model (B) There are substantial amounts of islet-specific but not disease-specific T cells in the blood regardless of disease status (gray bars). T cells in the islets do circulate in the blood (red bar), but the total numbers of islet-specific T cells are not different between individuals with and without T1D. Enumerating only T cells derived from the islets can identify individuals having T1D. TCR clonotypes are a distinct property to identify islet-derived T cells. *** significantly different. ns, not significant.