Promotion of long-term heart allograft survival by combination of mobilized donor plasmacytoid dendritic cells and anti-CD154 monoclonal antibody

Infusion of donor immature dendritic cells (DC) can significantly prolong survival of organ allografts, and this is believed to be due to antigen recognition by T cells in the absence of co-stimulation. In this study we report that a single pre-operative infusion of donor-mobilized immature plasmacytoid dendritic cells (pDCs) is superior to that of other DC sub-sets in suppressing allograft rejection. The combination of pDC infusion with injection of anti-CD154 monoclonal antibody further inhibited graft rejection and, in 50% of the mice, led to indefinite graft survival. This finding suggests a role for the plasmacytoid DC sub-set in facilitating organ transplant survival and also in the treatment of autoimmune disorders.