Transplantation. Author manuscript Page /1 6 Mediators involved in the immunomodulatory effects of apoptotic cells

Immunomodulatory properties are attributed to apoptotic cells. These properties have been used to modulate allogeneic immune responses in experimental transplantation settings. In independent studies, apoptotic cell infusion has been shown to favor hematopoietic cell engraftment, to increase heart graft survival and to delay the lethal onset of graft-versus-host disease (GVHD). The goal of this review was to discuss how apoptotic cell infusion interferes with graft rejection or host rejection (i.e., GVHD) and to focus on the potential mediators or perpetuators involved in apoptotic cell-induced immunomodulation. Particular emphasis on apoptotic “ ” cell phagocytosis, TGF- secretion and regulatory T cell induction was performed. Stimulating naturally immunosuppressiveβ “ ” molecules (i.e., TGF-) or immunomodulatory cells ( alternatively-activated macrophages, certain DC subsets or regulatory T cells)β “ ” in a physiological manner by using apoptotic cell infusion can be a promising way to induce tolerance