The role of the extracorporeal photopheresis in the management of the graft-versus-host disease

Over the last decades significant advances have been made in the field of donor selection, alternative transplant sources, immunosuppressive treatment and supportive care, as well as in the better understanding of the immunobiology of allogeneic hematopoietic stem cell transplantation (alloTx). Nevertheless, several factors still affect unfavorably the outcome of the procedure. Graft-versus-host disease (GvHD) remains the leading cause of morbidity, non-relapse mortality and treatment failure post alloTx. So far, steroids are the widely used 1st line treatment for GvHD achieving considerable response rate however, patients who fail to respond to the initial therapy have a dismal prognosis and no standard treatment is well established for them to date. In recent years, extracorporeal photopheresis (ECP) has been proposed as an efficacious and safe treatment for steroid refractory GvHD. Overall responses of 75% have been reported in the cutaneous and mucosal involvement and 45–65% in other organ manifestations (lung, liver and intestinal), allowing reduction and even discontinuation of steroids, thus contributing towards a significant reduction of morbidity. Although the mechanism of action of ECP is not fully understood, it seems that it has an immunomodulatory rather than an immunosuppression effect and induces immunotolerance, preserving the beneficial graft-versus-tumor effect. Given these very promising results in steroid-refractory or steroid-depended GvHD, currently, extracorporeal photopheresis is being investigated as both first-line and prevention therapy also.