Accordingly, activation of TLR9 by endogenous ligands has been reported to be protective in autoimmunity, and TLR9-deficient mice exhibit exacerbated symptoms of myelin oligodendrocyte glycoprotein- (MOG-) induced EAE [4], as well as an enhanced susceptibility to experimental type 1 diabetes [5]. Here, TLR9 is linked to type 1 diabetes mellitus.