Progress in the clinical application of immunosuppressive drugs in renal transplantation.

Although only very few new immunosuppressive drugs have been approved over the past two decades, the introduction of each new drug has progressively reduced the incidence of acute rejection and raised hopes that there would be an increase in long-term allograft survival. It is now consistently possible to achieve acute rejection rates of between 10 and 20%, and in many studies the rate has fallen below 10%. This is important, as acute rejection is one of the most important factors reducing the long-term survival of the allograft as a consequence of the development of chronic allograft nephropathy. The availability of these new agents has allowed experimentation with diverse protocols that explore the possibility of reduced exposure to calcineurin inhibitors and corticosteroids. These include both 'avoidance' and 'withdrawal' protocols. The target of rapamycin inhibitors, sirolimus and everolimus, have extended this paradigm. It is possible, but not yet proved, that their antiproliferative effect on smooth muscle will retard the vascular remodelling characteristic of chronic allograft nephropathy, atherosclerosis and hypertension. This review concentrates on the current progress being made in clinical immunosuppression, and includes data presented at the Transplant 2001 meeting of the American Society of Transplantation and the American Society of Transplant Surgeons, held in May 2001.