Extracorporeal photochemotherapy: a historical perspective

Vascular access considerations for extracorporeal photopheresis

Extracorporeal photopheresis is an immunomodulatory therapy indicated for patients with cutaneous T-cell lymphoma, graft-versus-host disease, and heart or lung allograft rejection. Whole blood from the patient is drawn into the photopheresis instrument where it is separated into its components. Plasma, red blood cells, and the treated buffy coat are subsequently returned to the patient. Consistent, adequate blood flow is necessary to successfully complete the procedure. Vascular access options for photopheresis include peripheral vein cannulation, tunneled central venous catheters, and subcutaneous ports. Photopheresis is a very safe procedure; however, the complications and impact on the patient's quality of life associated with vascular access devices can be significant.

Extra corporeal photochemotherapy in steroid refractory graft versus host disease: A review of guidelines and recommendations

Regardless of remarkable progresses in prevention and treatment approaches, graft versus host disease (GVHD) remains a major impediment for successful allogeneic hematopoietic stem cells transplantation (HSCT) and leads to morbidity and mortality in transplanted patients. Corticosteroids are the standard therapy for GVHD; however, a great number of patients will not respond sufficiently and others will be significantly affected by adverse effects of steroids. Extracorporeal photochemotherapy (ECP), as one of the numerous second line therapies, through modulation of immune cells may improves GVHD affected organ function in steroid-refractory forms. Considering to widespread utilization of ECP as a therapeutic strategy, we performed review on current literature of ECP, regarding the treatment strategies, monitoring protocols and technical aspects in chronic and acute GVHD.

Extracorporeal photopheresis: Review of technical aspects

Extracorporeal photochemotherapy (ECP) is considered as an immune modulating therapy majorly targeting the T cells of the Immune system. ECP induces an anti-inflammatory condition with tolerogenic responses without inducing a global immunosuppression state which is a typical feature of other therapeutic options such as steroids. Clinical indication of ECP has grown over time since its initial applications. Our review discusses the technical aspects of the concept of photopheresis with the available methods for its clinical applications.

Extracorporeal photopheresis: technique, established and novel indications

Extracorporeal photopheresis (ECP) has had a major impact in the treatment of various conditions in the past 25 years. Although it was initially developed for the treatment of patients with resistant cutaneous T cell lymphoma (CTCL), this therapy was later used to treat recipients of solid organs and stem cell transplants with rejection or graft-versus-host disease (GVHD), respectively. A significant number of patients with CTCL can achieve long term remission with ECP therapy. Those patients with heart or lung transplants may experience fewer or shorter rejection episodes following ECP. Furthermore, patients that respond to ECP can generally reduce the dose of immunosuppression medication, thus minimizing the morbidity caused by drugs such as corticosteroids and calcineurin inhibitors. While the exact mechanism of action of ECP is not well-understood, evidence suggests that reinfusion of the patient's apoptotic white blood cells, the ultimate product of ECP, promotes immunomodulatory events that are beneficial in patients with CTCL, transplant rejection, GVHD, and possibly other inflammatory conditions.

Extracorporeal photopheresis, a therapeutic option for cutaneous T-cell lymphoma and immunological diseases: state of the art

INTRODUCTION

Extracorporeal photopheresis (ECP) has been extensively used for the treatment of immune-mediated diseases for over 20 years and has a consistent and predictable safety profile with long-term use. Documenting the efficacy of ECP as therapeutic treatment has long been a matter of importance for physicians.

AREAS COVERED

The authors reviewed publications in this field with the goal of providing an overview of this therapeutic approach.

EXPERT OPINION

ECP is efficacious in a high percentage of those cutaneous T-cell lymphoma patients who have circulating malignant T cells in the context of a still-near-normal immune competence. From the side of graft-versus-host disease (GVHD), the use of ECP showed a clinical benefit in patients with steroid-refractory acute GVHD (aGVHD) and it is believed that ECP deserves to be evaluated as part of a combination strategy in first-line therapy of aGVHD. In chronic GHVD, the published data show that ECP can be effective in extensive and long-standing disease even when treatment is initiated at an advanced stage after conventional immunosuppressive and corticosteroid therapy has failed. ECP should be considered most beneficial for patients with predominantly mucocutaneous chronic GVHD. The fields of application of the procedure could be vast, and could also include autoimmune and metabolic diseases. The most important methodological issues which affect ECP evaluation is that the large majority of data about ECP result from single-arm observational series and the significant efficacy is mainly based on small and retrospective studies. ECP has never been proved to offer any survival advantage in a context of a randomized trial and the above-mentioned limitation also affects the accuracy of many biological modifications observed during ECP. Starting from these considerations, the need of a prospective randomized study becomes increasingly urgent.

The Combination of Immunosuppressive Drugs with 8-Methoxypsoralen and Ultraviolet a Light Modulates the Myeloid-Derived Dendritic Cell Function

The functional properties of myeloid dendritic cells (DCs) differ, depending on microenvironmental factors as well as on their stage of maturation. The main approaches for the selective enhancement of the tolerogenic properties of DCs include the induction of a pharmacological arrest of the DCs maturation and the genetical engineering of DCs expressing immunosuppressive molecules. Several immunosuppressive/anti-inflammatory agents have been discovered that potentially inhibit DC maturation and immunogenicity. Photopheresis (ECP) is an immunomodulatory therapy in which leucocytes are exposed to 8-methoxypsoralen (8-MOP) and ultraviolet (UV) A radiation (PUVA). The combination of ECP with immunosuppressive agents has demonstrated efficacy in the management of transplanted patients by reducing either the incidence of organ rejection or the pharmacological toxicity. In particular, we have observed in hepatitis C virus (HCV)-positive patients that the same combination has reduced the immunosuppressive burden and improved sustainability and efficacy of pre-emptive antiviral therapy after liver transplantation. Therefore, in our work we investigated the in vitro effects of PUVA, combined with immunosuppressive drugs (IDs), on both in vitro human DC generation and maturation, in order to contribute to understanding the immunological mechanisms underlying this pharmacological combination. Monocyte PUVA-treatment was performed by using an in vitro experimental protocol that we previously described. PUVA-treated or -untreated highly purified CD14+ cells were incubated with the association of the immunosuppressive drugs, used in the management of liver transplantation, at two different concentrations, in the presence of IL-4 and GM-CSF. The treatment with IDs at the highest concentration (corresponding to that used in clinical practice), alone or in association with PUVA, induced an immunosuppressive effect, by impairing both DC generation and maturation. Neither immunosuppressive drugs at the lowest concentration nor their combination with PUVA affected myeloid DC generation, but modified DC functions, strengthening the induction of a tolerogenic pattern. As this ID concentration was arbitrarily chosen, further experiments could highlight whether lower concentrations than those used in clinical practice would elicit the same effect on DCs and potentially improve their functional properties. This work describes an original experimental approach exploring the in vitro mechanism of action of the combined procedure of PUVA with immunosuppressive drugs, used in liver transplantation, on DCs generation and function. Our results contribute to the knowledge of the mechanisms of action of this combined procedure on DCs, suggesting useful therapeutic implications for the in vivo therapy.

[Rationale for the use of extracorporeal photochemotherapy in children]

The management of immune diseases in children remains challenging, although significant advances have been made. In addition to pharmacological approaches, extracorporeal photochemotherapy (ECP) is distinctive in its ability to provide immunomodulation without immune suppression or toxicity. However, in practice, this therapy is not widely used because of logistical issues and the lack of robust clinical pediatric studies. Here, we discuss the potential clinical applications of ECP in children and emphasize the need for a rigorous and specifically pediatric clinical evaluation of ECP.

Extracorporeal photopheresis affects co-stimulatory molecule expression and interleukin-10 production by dendritic cells in graft-versus-host disease patients

Graft-versus-host disease (GVHD) is a major complication of allogeneic bone marrow transplantation. Extracorporeal photochemotherapy (ECP) has been introduced as an alternative treatment for GVHD refractory to conventional immunosuppressive treatment, although its mechanism of action is not yet clear. We investigated, in seven GVHD patients, the effects of ECP on dendritic cell maturation and cytokine production in an in vitro model that could mimic the potential in vivo effect of reinfusion of ECP-treated peripheral blood mononuclear cells. The model was based on co-culture of ECP-treated lymphocytes with monocyte-derived dendritic cells (DCs) of the same patient. We found that the co-culture of ECP-treated lymphocytes with immature DCs reduced CD54, CD40 and CD86 mean fluorescence intensity (MFI) significantly after lipopolysaccharide (LPS) stimulation, without affecting human leucocyte antigen D-related and CD80 MFI. In the same co-culture model, DCs produced increased amounts of interleukin (IL)-10 when co-cultured with ECP-treated lymphocytes and stimulated with LPS, while IL-12 and tumour necrosis factor-alpha production were not affected. These results suggest that reinfusion of large numbers of autologous apoptotic lymphocytes is significant for the therapeutic outcome of ECP through down-regulation of co-stimulatory molecules on DCs, inducing non-fully mature DCs with a low signal 2 and up-regulation of IL-10, which is an immunosuppressive cytokine.

In vitro treatment of monocytes with 8-methoxypsolaren and ultraviolet A light induces dendritic cells with a tolerogenic phenotype

Extracorporeal photopheresis (ECP) has been considered an efficient dendritic cell (DC) therapy, used for treating both T cell malignancy, as well as T cell-mediated diseases. During the ECP procedure leucocytes are exposed to photoactivable agent 8-methoxypsolaren (8-MOP) and ultraviolet (UV) A radiation (PUVA) prior to reinfusion. Despite its clinical efficacy the mechanism of action remains elusive. As it has been reported that ECP might promote the differentiation of monocytes into immature DCs, we investigated the effects of UVA light (2 J/cm(2)) and 8-MOP (100 ng/ml) on in vitro monocyte-to-DC differentiation from normal donors. DCs were generated from human purified CD14(+) cells. Because monocytes are killed by PUVA and taking into account that only 5-10% of circulating mononuclear cells are exposed to PUVA during the ECP procedure, we developed an assay in which 10% of PUVA-treated monocytes were co-cultured with untreated monocytes. We first demonstrate that the presence of 10% apoptotic cells and monocyte activation were not enough to induce monocyte differentiation into DCs. Adding cytokines to our culture system, we obtained immature DCs characterized by significantly higher phagocytic activity and human leucocyte antigen D-related (HLA-DR) expression. These DCs preserved the capacity to be activated by lipopolysaccharide, but showed a reduced capacity to induce allogeneic T cell proliferation when first co-cultured with 10% of PUVA-treated cells. Our experimental design provides a novel insight into the real action of 8-MOP and UVA light on dendritic cell biology, suggesting an additional mechanism by which 8-MOP and UVA light exposure may influence immune responses.

Care for patients undergoing extracorporeal photopheresis to treat chronic graft-versus-host disease: review of the evidence

Late immune dysregulation following allogeneic hematopoietic cell transplantation (HCT) is known as chronic graft-versus-host disease (GVHD), which is a major cause of mortality and morbidity after HCT, and a rise in its incidence is predicted. Better therapies are being sought to manage chronic GVHD and limit patients' exposure to corticosteroids. Extracorporeal photopheresis (ECP), an immune-modulating therapy, has shown preliminary safety and efficacy in treating chronic GVHD. However, access to ECP is limited, care is costly, and the optimal frequency, duration, and durability of response are unknown. Although nurses who care for patients with chronic GVHD recognize its adverse impact on patients' quality of life, limited evidence exists about the selection of patients most likely to benefit from ECP therapy and from the supportive care provided to them. A multidisciplinary approach is needed to define the desired outcomes of ECP therapy and to determine the evidence base for nursing management approaches.

Assessment of 8-methoxypsoralen and ultraviolet a light effects on human stroma generation and function

Photopheresis or extracorporeal photochemotherapy (ECP) is a new immunomodulatory therapy in which a patient's leukocytes are exposed extracorporeally to 8-methoxypsoralen (8-MOP) and ultraviolet A (UVA) light. Although it is used for the treatment of cutaneous T cell lymphoma, graft-versus-host disease, and several autoimmune diseases, with efficacy and safety reported in almost all studies, the mechanisms by which ECP exerts its beneficial effects are still unclear. As cellular targets of this procedure are numerous, we investigated the effects of 8-MOP and UVA light on stromal precursors and mature stromal layers. Human bone marrow stromal cell layers were established in long-term bone marrow culture medium from normal marrow mononuclear cells. Normal marrow mononuclear cells were incubated with 8-MOP and/or exposed to UVA light (PUVA treatment) before culturing. A control without 8-MOP and UVA was also included in the study. Apoptosis induction was evaluated using annexin V following 7 days after PUVA. After 4-6 weeks of culture, stromal layers were examined under a phase-contrast microscope to identify structural differences between PUVA-treated and control stroma. To determine whether PUVA treatment affected stromal regulation of adherent hematopoietic cell survival, mature stromal layers, incubated with 8-MOP and exposed to UVA light, were cocultured with nonadherent mononuclear cells from normal marrow. After 24 h, the percentage of apoptotic hematopoietic cell precursors was quantified by flow cytometry. This study provides evidences that the in vitro exposure of human stromal cell precursors to UVA light, in the presence of 8-MOP, inhibits stromal layer generation by inducing apoptosis, as evidenced by annexin V staining following 7 days of culture. Here, we show an additional cell target for this psoralen following UVA irradiation. However, in a second set of experiments, PUVA treatment did not affect the stromal capacity to support hematopoiesis in culture. Our results can contribute to a better definition of ECP mechanisms of action for future development of experimental designs and clinical applications of this intriguing procedure.

Quo vadis haemapheresis. Current developments in haemapheresis

The techniques of haemapheresis originated in the development of centrifugal devices separating cells from plasma and later on plasma from cells. Subsequently membrane filtration was developed allowing for plasma-cell separation. The unspecificity of therapeutic plasma exchange led to the development of secondary plasma separation technologies being specific, semi-selective or selective such as adsorption, filtration or precipitation. In contrast on-line differential separation of cells is still under development. Whereas erythrocytapheresis, granulocytapheresis, lymphocytapheresis and stem cell apheresis are technically advanced, monocytapheresis may need further improvement. Also, indications such as erythrocytapheresis for the treatment of polycythaemia vera or photopheresis though being clinically effective and of considerable importance for an appropriate disease control are to some extent under debate as being either too costly or without sufficient understanding of the mechanism. Other forms of cell therapy are under development. Rheohaemapheresis as the most advanced technology of extracorporeal haemorheotherapy is a rapidly developing approach contributing to the treatment of microcirculatory diseases and tissue repair. Whereas the control of a considerable number of (auto-) antibody mediated diseases is beyond discussion, the indication of apheresis therapy for immune complex mediated diseases is quite often still under debate. Detoxification for artificial liver support advanced considerably during the last years, whereas conclusions on the efficacy of septicaemia treatment are debatable indeed. LDL-apheresis initiated in 1981 as immune apheresis is well established since 24 years, other semi-selective or unspecific procedures, allowing for the elimination of LDL-cholesterol among other plasma components are also being used. Correspondingly Lp(a) apheresis is available as a specific, highly efficient elimination procedure superior to techniques which also eliminate Lp(a). Quality control systems, more economical technologies as for instance by increasing automation, influencing the over-interpretation of evidence based medicine especially in patients with rare diseases without treatment alternative, more insight into the need of controlled clinical trials or alternatively improved diagnostic procedures are among others tools ways to expand the application of haemapheresis so far applied in cardiology, dermatology, haematology, immunology, nephrology, neurology, ophthalmology, otology, paediatrics, rheumatology, surgery and transfusion medicine.

Photopheresis in solid organ transplant rejection

Photopheresis has become a key component in the therapeutic armamentarium of cutaneous T-cell lymphoma, graft-versus-host disease following stem cell transplant, and allograft rejection of solid organs such as heart. Although it is considered a new treatment modality in its present form, the field of phototherapy dates back thousands of years. In this review, the reader will learn more about the history of photopheresis and how it became a therapeutic alternative for patients with solid organ transplants. An extensive literature search will highlight the evidence-based benefits of photopheresis (or lack thereof). A discussion of the mechanism of action of photopheresis and the technical aspects of the procedure will also be covered. Since photopheresis may be the best tolerated form of immunomodulation, current promising, albeit preliminary data on its efficacy warrant further investigation and understanding.

Small-scale extracorporeal photopheresis for the treatment of cutaneous T-cell lymphoma: A report of 3 cases

Extracorporeal photopheresis is an accepted method for the treatment of cutaneous T-cell lymphoma and much progress has recently been achieved in therapy and understanding of its mechanism. In general large numbers of white blood cells are collected by a cell separator and irradiated in the presence of 8-MOP. In contrast to this practice, data from an animal model showed that as few as 0.2% of the body's blood volume irradiated are sufficient to achieve an immune response after photopheresis. Based on these data we developed a small-scale photopheresis procedure and applied the method in 3 end-stage T-cell lymphoma patients who were not eligible for apheresis. The mononuclear cells from 50 ml of blood were separated by density gradient centrifugation, irradiated with UV-light in the presence of 8-Methoxy-Psoralen (MOP) with 2J/cm(2) and reinjected. 2-3 treatments per week were conducted. The three patients-2 male and 1 female, age 63-86, Sezary syndrome (1x) and mycosis fungoides in tumour stage (2x)-showed no side effects on cell injection. The two patients with mycosis fungoides showed a prompt regression and softening of the tumours. The patient with Sezary syndrome developed numerous necrotic spots on the skin after 6 weeks of therapy that turned normal within a few days. Patient 1 died of pneumonia 4 weeks after the start of therapy and patient 3 died of heart failure 8 weeks after start of therapy, both during regression of the tumours. Patient 2 was treated over a period of 11 months, with an initial regression in the first weeks followed by a slow progression of the tumours after she rejected any form of further treatment. The small-scale extracorporeal photopheresis therapy presented is effective in cutaneous T-cell lymphoma. But questions regarding the optimal number of cells irradiated per treatment, the conditions of cell incubation after irradiation and the number of treatment cycles are still open. Therefore further studies are required to establish a method that is effective and circumvents the use of apheresis technology.