IL17A and diabetes mellitus: Thus, there is a need to better understand how IL-17 may modulate susceptibility to Type 1 diabetes by linking intestinal changes to type 1 diabetes development.<h4>Methods</h4>We studied IL-17-deficient NOD mice to understand the role of IL-17 in mediatingsusceptibility to Type 1 diabetes in vivo and in vitro.<h4>Results</h4>Our study showed that IL-17-deficient NOD mice were protected from autoimmune diabetes, and <i>in vivo</i> adoptive transfer studies showed that both immune and non-immune cells are important for modulating diabetes development.