Immune suppression with cyclosporin A-optimism and caution.

There have been no fundamental changes over the past 15 to 20 years in the immunosuppressive agents used in clinical transplantation. Equally efficient, but less toxic alternatives have been sought for some time. Cyclosporin A is an important new pharmacological immune suppressant, with a unique structure, which prolongs graft survival in a variety of species. It exerts a highly selective inhibitory effect on those T lymphocytes responding to antigenic challenge and is not myelotoxic. Indeed, no toxic effects have been reported at therapeutic doses in animals. Clinical trials indicate that it could prove extremely useful in management of graft rejection and autoimmune disease, however there are some doubts regarding possible hepatotoxic and nephrotoxic effects in man. There is also concern over the reported incidence of malignant lymphomas in cyclosporin A treated graft recipients.