The novel immunomodulator FTY720 is remarkably effective in models of transplantation and autoimmunity. Recent data show that phosphorylated FTY720 is an agonist at four sphingosine 1-phosphate receptors. Stimulation of sphingosine 1-phosphate receptors leads to sequestration of lymphocytes in secondary lymphatic tissues and thus away from inflammatory lesions and graft sites. (C) 2002 Elsevier Science Ltd. All rights reserved.