Innate immunity in transplantation

Rejection remains a major barrier to transplant survival. Cells in both the innate and adaptive arms of the immune system conspire with one another to mount robust transplant rejection. Recent studies suggest that innate immune cells are critically involved in determining whether a transplant is rejected or accepted, highlighting the need to therapeutically targeting innate cells, in addition to adaptive cells, in the induction of transplant tolerance. Here, we review key cells and molecular pathways in the innate immune system, how the innate system responds to allotransplants, and the challenges and opportunities in therapeutic re-programming the innate immune system in transplant settings.