The future of organ and tissue transplantation - Can T-cell costimulatory pathway modifiers revolutionize the prevention of graft rejection?

Transplantation therapies have revolutionized care for patients with endsta ge organ (kidney, liver, heart, lung, and pancreatic g-cell) failure, yet s ignificant problems persist with treatments designed to prevent graft rejec tion. Antirejection therapies are not always effective, must be taken daily , and are both expensive and associated with well-known toxic effects; Rece nt advances have suggested that the immune system has more self-regulatory capability than previously appreciated. In this review, we discuss immune s ystem function and new therapeutic agents that modify so-called costimulato ry receptor signaling to support transplant function without generally supp ressing the immune system.