Previous studies have described several mechanisms of feto-maternal tolerance that minimize the activation of naive T cells specific for fetal or placental antigens. In this study, the authors found that re-activation of memory T cells with known fetal or placental specificity in early pregnancy did not result in fetal rejection, suggesting the existence of additional tolerance mechanisms. Unlike myometrial stromal cells, decidual stromal cells (DSCs) — which encapsulate the fetus and placenta — were shown to express only very low levels of the T cell chemoattractants CCL5, CXCL9 and CXCL10 under inflammatory conditions in vivo, thereby preventing T cell accumulation in the decidua. This specific reduction in chemokine expression by DSCs was due to repressive histone modifications in the promoters of the encoding genes. Thus, limiting effector T cell accumulation within the decidua is an additional mechanism of feto-maternal tolerance.