Cyclosporine controversies.

Cyclosporine is a potent immunosuppressant with low myelotoxicity. It is approved for use to prevent rejection of kidney, liver, and heart transplants, and is being investigated for possible use for suppression of graft-versus-host disease in patients who have received bone marrow transplants. Although cyclosporine is generally thought of as an immunosuppressive agent for use in conjunction with transplantation, there are investigations underway that could result in wider applications.