Extracorporeal photochemotherapy as a challenging treatment for cutaneous T-cell lymphoma, acute and chronic graft-versus-host disease, organ rejection and T-lymphocyte-mediated autoimmune diseases

20 years ago, in 1987, Edelson and co-workers published their first report on the effectiveness of a new procedure, called extracorporeal photochemotherapy (ECP), in patients with advanced stage cutaneous T-cell lymphoma (CTCL). The positive response (> 70% overall) achieved in those patients encouraged several groups to try out this new technology in other T-lymphocyte-mediated autoimmune diseases and a number of dermatological diseases, which sometimes gave conflicting results. In the following years, ECP obtained FDA approval as first line treatment in CTCL. In the 1990s ECP was applied to acute and chronic graft-versus-host disease (GvHD) refractory to conventional immunosuppressive therapy and proved to be effective in > 60% of cases of this larger patient population. Today, although the effectiveness of ECP in GvHD is generally acknowledged, this is mainly based on retrospective or observational studies, as data from large, randomized multicenter trials, has yet to be published. Moreover, ECP's real mechanism of action and optimal treatment schedule are still under investigation. The aim of this review is to summarize knowledge acquired to date about ECP.