Tolerogenic properties of dendritic cells in allografting.

In this review we present current views on the mechanism of prolongation of organ allograft survival mediated by donor dendritic cells. The contemporary research focuses on problems as: a) is the DC microchimerism the cause or consequence of long-term graft acceptance, b) what is the role of DCs, which are derived from bone marrow, with respect to the cell trafficking and dissemination and site-specific function as related to the mechanism of tolerance. There is a large body of evidence indicating that DC play certain regulatory role in the process of induction of tolerance. Immaturity of DCs, bone marrow lineage, method of dissemination by infusion in suspension or from the vascularized bone marrow graft, location after transplantation and environment inhibiting their maturation seem to be the prerequisites for displaying their tolerogenic activity. The subtle balance between induction of tolerance or immunization does not allow today to use immature DC in clinical practice. Further studies, in particular in human recipients, are needed.