Update on the mechanism of action and on clinical efficacy of extracorporeal photopheresis in the treatment of acute and chronic graft versus host disease in children.

Extracorporeal photopheresis (ECP) has been used for treatment of steroid-refractory graft versus host disease (GVHD) with encouraging results. Although its exact mechanism of action is not fully understood, photoapheresed cells seem to induce a selective immune response directed against alloreactive T cell populations without causing generalized immunosuppression. Current pediatric experience with ECP for GVHD is available in the form of a few retrospective small studies concerning children with steroid refractory GVHD. Reviewing these data we conclude that ECP is a safe procedure, well tolerated even in low-weight pediatric patients, which warrants further evaluation in well-designed, prospective, controlled studies. Copyright Â