Specific maternal microchimeric T cells targeting fetal antigens in β cells predispose to auto-immune diabetes in the child

► Maternal T cells can be transferred to offspring during gestation or lactation and have T cell reactivity. ► Maternal T cell targeting the offspring beta cells can promote peri-insulitis. ► Fetal/offspring T cells initiation of islet infiltration depends on maternal reactivity against pancreatic beta cells.