Questions raised by the exclusion of ‘at risk’ conditions from current trials in organ transplantation

The recent development of new immunosuppressive agents may improve the overall results of organ transplantation and open new areas for clinical applications of allografts. The introduction of cyclosporin A 20 years ago brought drastic improvements in liver and heart transplantation, and these became routine treatment for irreversible hepatic or cardiac failure. New immuno-suppressors may have a comparable effect on lung, heart—lung and intestinal transplantation. However the whole clinical field of organ transplantation is moving: improvement in short-term results has led to such treatments being offered to ‘high-risk’ patients who were formerly excluded from transplantation: carefully designed clinical studies demonstrated that very young or elderly recipients, as well as diabetics or hyperimmunized patients could benefit from such treatments. Because of organ shortage, donors who were initially excluded for various reasons have finally become acceptable since cold ischemia time can be prolonged in kidney transplantation without major changes in failure rate.