Innate Immunity

Transplant rejection remains a major barrier to graft survival. Studies suggest that innate immune cells are critically involved in determining whether a transplant is rejected or accepted, highlighting the need to therapeutically target both innate and adaptive immune cells when seeking to establish transplant tolerance. The innate immune system consists of numerous cell types, molecular sensors, and soluble mediators that differ from those in the adaptive system, and are largely involved in instigating an adaptive response. In this chapter we review key cells and molecular pathways in the innate immune system, detail how the innate system responds to allotransplants, and summarize the challenges and opportunities in therapeutic targeting of the innate immune system in transplant settings.