Immunophilins in the Nervous System

The term immunophilin is used to designate receptors for immunosuppressant drugs such as cyclosporin A (CsA), FK506, and rapamycin. In clinical medicine, immunosuppression is used therapeutically for a variety of purposes. One of the most important is the treatment of patients undergoing organ transplantation to prevent host-versus-graft rejection (Morris 1991; Fung and Starzl 1994). Immunosuppression also diminishes symptoms of autoimmune disease such as myocarditis and glomerulonephritis (Thomson and Starzl 1992). Historically, immunosuppression was achieved with drugs that inhibit cell division, as lymphocytes tend to divide more rapidly than mature somatic cells. Accordingly, mitotic inhibitors employed in cancer chemotherapy, such as methotrexate, have been extensively employed as immunosuppressants, but with significant toxicity. In contrast, modern immunosuppressants, of which the first widely employed agent was CsA, demonstrate a reasonable degree of selectivity for the immune system.