Technology Insight: ECP for the treatment of GvHD—can we offer selective immune control without generalized immunosuppression?

Hemopoietic stem-cell transplantation (HSCT) remains an important curative therapy for many malignant and non-malignant conditions and its use worldwide is increasing. Although many advances have been made in this field, graft-versus-host disease (GvHD), or its treatment, is responsible for causing high morbidity and mortality in patients potentially cured from their primary disease. This review summarizes the successful treatment of steroid refractory-dependent acute and chronic GvHD with extracorporeal photochemotherapy. Hematopoietic stem-cell transplantation remains an important curative therapy for many conditions and its use is increasing annually. Graft-versus-host disease (GvHD) is the major cause of mortality and suffering following allogeneic hematopoietic stem-cell transplantation. Conventional treatments are associated with multiple side effects and are often ineffective. New therapeutic approaches for the control of GvHD are desperately required. Extracorporeal photochemotherapy (ECP) was developed in the 1970s for the treatment of cutaneous T-cell lymphoma and was approved by the FDA as the first selective immunotherapy for a cancer. ECP has also proved an effective therapy for immune-related conditions, particularly GvHD, even in patients refractory to conventional therapies. The treatment involves the mechanical separation of circulating white cells, which are exposed to psoralen and UVA light and then returned to the patient. ECP is extremely well tolerated with minimal side effects and is not associated with the increased rates of infection or relapse of malignant disease typical of conventional immunosuppressive agents. Thus, ECP appears to offer selective immune modulation without generalized immunosuppression, but its mechanism of action remains poorly understood. This review discusses the development of ECP, its use in the treatment of GvHD, as well as current theories of its mechanism of action. Key Points Graft-versus-host disease (GvHD) remains the major cause of non-relapse morbidity and mortality following allogeneic hematopoietic stem-cell transplantation Extracorporeal photochemotherapy (ECP) was developed for the treatment of cutaneous T-cell lymphoma and was found to have activity in other T-cell-mediated diseases ECP is a novel approach to GvHD therapy that appears to offer control of GvHD without generalized immunosuppression and its associated complications There is reasonable evidence to support the use of ECP for the tre