Extracorporeal photochemotherapy--present and future.

Extracorporeal photochemotherapy (ECP) was introduced by Edelson and co-workers in 1985. Since then the therapy, though still controversial in specific indications, has received wide acceptance and is presently been used in over 160 centers in Europe and the U.S.A. for a number of important dermatological and non-dermatological indications. Convincing data in the past few years has documented that ECP is associated with a very low side-effect profile. As of 2000 ECP continues to be used in the treatment of cutaneous T-cell lymphoma, alone or in combination with other treatment modalities, and increasingly in the management of additional T-cell mediated diseases, acute as well as chronic Graft versus Host Disease (GvHD) after allogeneic bone marrow transplantation in particular. ECP has also been shown to play an important role in the treatment of acute as well as chronic allograft rejection, in renal, lung, and cardiac transplant recipients and lately steroid refractory inflammatory bowel disease. A number of mechanisms for its efficacy have been proposed whereby at present induction of anticlonotypic immunity directed against pathogenic clones of T lymphocytes may be an important concept. Treatment related apoptotic death of involved T cells and concurrent activation of antigen presenting cells may also closely relate to mechanisms associated with this therapy.