New immunosuppressive treatment in transplantation medicine.

Currently, the standard immunosuppressive regimen in organ transplantation is centred around cyclosporin. However, despite the use of this drug, rejection is not uncommon and it is associated with significant side-effects. Novel drugs and regimens have been developed to combat allograft rejection. Although FK506 has a similar mode of action and toxicity profile to cyclosporin, results, particularly in the rescue situation, have been encouraging. Sodium brequinar and rapamycin inhibit lymphocyte proliferation and may be most effective when used in combination with cyclosporin. Mycophenolate mofetil has been used in the treatment of psoriasis for many years; it is safe and will perhaps be useful in second-line therapy in patients unable to tolerate cyclosporin. The specific drugs highlighted in this chapter, although successful to differing degrees in preventing immunological rejection of allografts, have wide-ranging toxic effects on other organs in the body. Future use of these drugs is likely to utilize lower doses, supplemented by specific monoclonal antibody therapy, which can target diverse arms of the immune response. Large clinical trials using monoclonal antibodies against the T-cell receptor, the IL-2 receptor, CD4 T cells and specific adhesion molecules such as ICAM-1 are eagerly awaited. The number of new drugs and their mechanism of action, together with the widening spectrum of monoclonal antibodies available, will ensure that the next decade will be an exciting and hopefully profitable period in transplantation medicine. It is hoped that the introduction and assessment of these new agents will be rather more systematic and objective than that of their antecedents.