CD70 and type 1 diabetes mellitus: Importantly, the sole expression of CD70 by immature DCs was shown to regulate immunity versus tolerance, highlighting the critical role of CD27-CD70 interactions at the interface between T cell and DC Our observations are in line with previous reports showing that the CD27/CD70 pathway triggers Treg development in thymic niches by rescuing differentiating cells from apoptosis (18), induces Treg accumulation in solid tumors in mice (58) and supports the generation of Tregs involved in the control of type 1 diabetes in NOD mice (59).