Gene therapy in transplantation: Toward clinical trials

The genetic modification of organs or cells is an attractive approach to protect allogeneic transplants from acute rejection and other complications. The transplant setting offers a unique opportunity to utilize ex vivo gene therapy for the modification of allogeneic organs and tissues prior to implantation. However, significant challenges exist in the application of this concept to human organ transplantation, including the large number of potential molecular targets, the diversity and safety profile of available vector delivery systems and the merging of gene-based therapies with existing immunosuppressive regimens. Accordingly, many different therapeutic concepts and vector systems have been investigated in preclinical studies with the aim of prolonging allograft survival. However, the translation of promising gene therapy strategies to transplant clinical trials has lagged behind the progress made in other medical fields. This review describes the recent preclinical applications of gene transfer to transplantation, and critically evaluates the degree to which gene therapy has been tested clinically in organ transplant recipients.