Immunology of pediatric renal transplantation

Allograft rejection is an inflammatory reaction that typically occurs rapidly after transplantation in association with a characteristic cellular and humoral attack on the graft. However, the rejection process can also occur more insidiously, as a result of a chronic immunological process involving delayed-type hypersensitivity mechanisms. Both the early acute and the later chronic rejection processes are mediated by the recipient’s immunological response to donor antigen, which is initiated and coordinated by CD4 T cells. All forms of rejection also require the activation of other cell types including B cells and macrophages as well as the induced expression of adhesion molecules that enable the trafficking of destructive effector cells into an allograft. New discoveries in the field of immunology have provided many insights into mechanisms that function in the alloimmune response and in the development of rejection. Several of these discoveries have recently been translated into the clinic as new therapeutics that have potential to promote long-term graft survival. In this chapter, the cellular and molecular basis for the alloimmune response as well as the mechanisms and concepts that have resulted in new targeted therapeutic strategies will be reviewed.