Extracorporeal photopheresis for the treatment of severe, refractory steroid dependent pediatric Crohn's Disease

Extracorporeal Photopheresis-An Overview

Extracorporeal photopheresis (ECP) has been in clinical use for over three decades after receiving FDA approval for the palliative treatment of the Sézary Syndrome variant of cutaneous T-cell lymphoma (CTCL) in 1988. After the first positive experiences with CTCL, additional indications have been successfully explored including areas such as graft-vs.-host disease (GVHD), scleroderma, and solid organ transplantation. The mechanism of action is still not fully resolved, but important steps in understanding ECP in recent years have been very informative. Originally, the primary hypothesis stated that psoralen and ultraviolet A (UVA) in combination induce apoptosis in the treated immune cells. This view shifted in favor of dendritic cell initiation, modification of the cytokine profile and stimulation of several T-cell lineages, in particular regulatory T-cells. A number of ECP guidelines have been produced to optimize treatment regimens in the clinical context. In CTCL, enough evidence is available for the use of ECP as a first line treatment for Sézary Syndrome (SS), but also as a second line or rescue treatment in therapy-refractory forms of mycosis fungoides (MF). ECP in the treatment of acute and chronic GVHD has shown promising results as second line therapy in steroid-refractory presentations. In solid organ transplantation, ECP has been used to increase tissue tolerance and decrease infections with opportunistic pathogens, attributed to the use of high doses of immunosuppressive medication. Infection with cytomegalovirus (CMV) remains a limiting factor affecting survival in solid organ transplantation and the role of ECP will be discussed in this review. A trend toward prophylactic use of ECP can be observed and may further contribute to improve the outcome in many patients. To further deepen our knowledge of ECP and thus facilitate its use in patients that potentially benefit most from it, future prospective randomized trials are urgently needed in this rapidly growing field. The aim of this review is to (1) introduce the method, (2) give an overview where ECP has shown promising effects and has become an essential part of treatment protocols, and (3) to give recommendations on how to proceed in numerous indications.

Miscellaneous indications for extracorporeal photochemotherapy (ECP)

Extracorporeal photochemotherapy (ECP) has been applied to many T-cell mediated diseases where immunosuppressive drugs are insufficient or not tolerated. As ECP is mainly used in rare indications after failure of other therapies, controlled studies are hardly possible. In addition, the importance of the extracorporeal circuit imposes ethical doubts in organising sham ECP procedure, which explains the rarity of controlled double-blind studies. However, encouraging and even successful results have been reported in newly developed diabetes mellitus, erosive lichen planus, Crohn's disease, systemic sclerosis, nephrogenic fibrosing dermopathy, atopic dermatitis, rheumatoid arthritis, systemic lupus erythematodes, psoriasis arthritis, cutaneous mucinosis, scleromyxoedema, pemphigus vulgaris, multiple sclerosis, eosinophilic fasciitis and in the prevention of percutaneous transluminal coronary angioplasty (PTCA) restenosis. This article discusses the various levels of evidence in the above cited indications.