Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracorporeal photopheresis (ECP) has been successfully used to treat some inflammatory conditions. Following ECP, lymphocytes become apoptotic and untreated monocytes, exposed to post-ECP lymphocytes, reduce proinflammatory cytokine secretion. This study attempted to establish if this monocyte immunosuppression was linked to phosphatidylserine externalization (detected using Annexin V) on the apoptotic lymphocytes. Using density gradient and magnetic separation, lymphocytes were isolated from three cutaneous T-cell lymphoma and nine chronic graft versus host disease (cGvHD) patients pre-ECP and prior to re-infusion (post-ECP). The collected lymphocytes were cultured overnight and Annexin V levels determined. Peripheral blood was taken from the same patient 20 h later and the monocytes were isolated. The 'fresh' monocytes were introduced to each 20 h pre- and post-ECP lymphocyte culture, stimulated with lipopolysaccharide (LPS) and Brefeldin A and subsequently tested for intracellular tumour necrosis factor alpha, interleukin 1 alpha (IL1alpha), IL1beta, IL6 and IL8. For cGvHD patients, the relative levels of IL1alpha and IL6 were reduced in the untreated, LPS-stimulated monocytes exposed to post-ECP lymphocytes. However, the down-regulation of IL1alpha and IL6 did not correlate to levels of Annexin V-positive lymphocytes. ECP-treated lymphocytes can reduce the ability of LPS-stimulated monocytes to produce some proinflammatory cytokines; however, this effect is not dependent on phosphatidylserine externalization.
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PMID:The down-regulation of IL1alpha and IL6, in monocytes exposed to extracorporeal photopheresis (ECP)-treated lymphocytes, is not dependent on lymphocyte phosphatidylserine externalization. 1657 48

Extracorporeal photochemotherapy (ECP; photopheresis), an immunomodulatory therapy developed for cutaneous T-cell lymphoma, has shown promise in treating chronic graft-versus-host disease (cGvHD) in uncontrolled studies. The purpose of this study was to further examine the effects of ECP on cGvHD. ECP (administered initially 3 times weekly on alternating days) was retrospectively evaluated in 14 patients with extensive cGvHD following allogeneic hematopoietic stem cell transplantation. The median time from transplantation to ECP initiation was 29 months (range, 5-96 months). The median number of concomitant baseline treatments per patient was 3 (range, 0-5). During a median ECP duration of 17 months (range, 3-44 months), 3 patients (21%) achieved a complete cutaneous response (100% improvement), 4 patients (29%) achieved a partial cutaneous response (> or =50% improvement), and 7 patients (50%) had stable skin disease. The median time to response was 6 months (range, 2-15 months), and the median response duration was 5 months (range, 1-31 months). At endpoint, responses were ongoing in 4 patients. Resolution or improvement was noted in arthralgia (5/7 patients), oral changes (3/7), elevated liver enzymes (3/5), dry eyes (2/5), joint stiffness (3/3), pulmonary disease (1/3), and thrombocytopenia (1/1). Because of a favorable response, 11 of 13 patients (85%) who received prednisone at baseline were able to taper (7/13; 54%) or discontinue (4/13; 31%) this medication, and 12 of 14 patients (86%) were able to taper (11/14; 79%) or discontinue (1/14; 7%) ECP. Five-year posttransplantation survival was 77%. Our results suggest that adjunctive ECP improves cutaneous and extracutaneous manifestations of cGvHD and has a steroid-sparing effect.
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PMID:Treatment of extensive chronic graft-versus-host disease with extracorporeal photochemotherapy. 1660 32

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.
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PMID:Photopheresis in solid organ transplant rejection. 1661 30

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.
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PMID:Technology insight: ECP for the treatment of GvHD--can we offer selective immune control without generalized immunosuppression? 1675 68

Induction of apoptosis and changes to cytokine secretion patterns have been implicated in the mechanism of action of extracorporeal photopheresis (ECP). Lymphocyte apoptosis is initially detected in significant numbers prior to re-infusion and by 48 h post-ECP the majority of treated lymphocytes are apoptotic. The early apoptosis involves changes to mitochondrial function, reversal of the Bcl-2/Bax ratio and externalisation of phosphatidylserine. Apoptotic lymphocytes, observed from 20 h post-ECP, are associated with enhanced levels of CD95 and Fas-ligand. For cutaneous T cell lymphoma (CTCL), processing of the apoptotic lymphocytes, by suitable antigen presenting cells (APCs), is suggested to induce a clonal cytotoxic response which targets the malignant T cell population. Increased levels of TNFalpha and IFNgamma, observed post-ECP in monocytes and lymphocytes, respectively, are thought to further contribute to the proposed anti-tumour reaction seen in CTCL. However, down-regulation of pro-inflammatory cytokines and enhanced anti-inflammatory responses have been reported following ECP treatment. These immune responses may contribute to the tempering of the inflammatory conditions, such as graft versus host disease, which respond to ECP. Furthermore, untreated monocytes exposed to ECP-treated lymphocytes have also demonstrated a shift in monocyte cytokine-secretory pattern, toward one associated with immune tolerance. Recently, a mechanism of ECP-induced immune tolerance has been linked to the stimulation of the anti-inflammatory cytokines IL10 and TGFbeta by T regulatory cells, following the infusion of ECP-treated CD11c(+) APCs. Ultimately, the multifaceted responses, induced by ECP, may explain the diversity of clinical conditions that benefit.
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PMID:Extracorporeal photopheresis: a focus on apoptosis and cytokines. 1679 26

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.
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PMID:Assessment of 8-methoxypsoralen and ultraviolet a light effects on human stroma generation and function. 1701 38

The generation of photoproducts of psoralen (POPs) might be relevant in cell death induced by psoralen plus UVA, namely PUVA, which is a recognized effective treatment for cutaneous T-cell lymphoma, chronic graft-versus-host disease, and psoriasis. We investigated the occurrence of POP-induced cell death and the underlying mechanisms. POPs were produced by irradiating a psoralen solution with UVA. Jurkat cells treated in the dark with these mixtures died mainly through an apoptotic mechanism. POPs were separated by high-performance liquid chromatography (HPLC), and cells were added with each of these fractions. A total of 2 dimers of psoralen and 6-formyl-7-hydroxycoumarin (FHC) were identified in the apoptogenic fractions. Apoptosis was preceded by mitochondrial dysfunction caused by the opening of the mitochondrial permeability transition pore (PTP). In fact, both mitochondrial depolarization and cell death were prevented by the PTP inhibitor cyclosporin A (CsA). PTP opening was also documented in isolated mitochondria added with POP, suggesting that apoptosis is caused by a direct effect of POP on mitochondria. In fact, FHC alone induced PTP opening and CsA-inhibitable cell death of Jurkat cells, whereas nontransformed T lymphocytes were resistant. Along with identifying novel apoptogenic molecules, the present results indicate that POP generation directs transformed cells to apoptosis.
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PMID:The mitochondrial effects of novel apoptogenic molecules generated by psoralen photolysis as a crucial mechanism in PUVA therapy. 1731 98

We evaluated the immunomodulatory and clinical effect of 279 extracorporeal photochemotherapy (ECP) procedures which were performed in six patients with chronic extensive GVHD and in two patients with CTCL (cutaneous T-cell lymphoma)/Mycosis fungoides. ECP was performed using the off line regimen. In five of six patients with c-GVHD the improvement of sclerodermatous skin changes, joint mobility, and the reduction of joint pain was observed. Two patients with CTCL responded to ECP with rapid improvement of the skin changes. In patients with c-GVHD and CTCL who responded to ECP efficiently, we found the similar tendency to increase in the number of CD 3/8+ T-lymphocytes and the decrease of CD 4/8 IRI. In patients with CTCL we observed also the decrease in levels of CD 3/4+ T-lymphocytes and in the number of leukocytes. The influence of ECP on T-cell subsets and on the dendritic cells function, which we observed in our previous study, leads to the suggestion that interactions between T-cell subsets and dendritic cells may participate in the process of ECP. ECP did not cause any significant changes in levels of IgG, parameters of liver and renal functions in patients with c-GVHD and with CTCL. No increased incidence of infections and no serious adverse reactions in patients have been observed so far.
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PMID:Extracorporeal photochemotherapy (ECP) in treatment of patients with c-GVHD and CTCL. 1737 42

Extracorporeal photopheresis (ECP) has been used for over 30 years in the treatment of erythrodermic cutaneous T-cell lymphoma (CTCL) and over 20 years for chronic graft-versus-host disease (cGVHD). The lack of prospective randomized trials has led to different centres having different patient selection criteria, treatment schedules, monitoring protocols and patient assessment criteria. ECP for CTCL and cGVHD is available only at six specialized centres across the U.K. In the recent Improving Outcomes Guidance the National Institute for Health and Clinical Excellence endorsed the use of ECP for CTCL and because of the complexity of treatment supported its use in specialized centres and also suggested the need for expansion of this service. In 2005 consultants and senior nurses from all U.K. sites and from Scandinavia formed a Photopheresis Expert Group. This group's first aim was to produce a consensus statement on the treatment of CTCL and cGVHD with ECP using evidence-based medicine and best medical practice, in order to standardize ECP eligibility, assessment and treatment strategies across the U.K.
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PMID:U.K. consensus statement on the use of extracorporeal photopheresis for treatment of cutaneous T-cell lymphoma and chronic graft-versus-host disease. 1824 Dec 74

Extracorporeal photopheresis (ECP), a technique that exposes isolated white blood cells to photoactivatable 8-methoxypsoralen and ultraviolet A radiation, is used clinically to treat cutaneous T-cell lymphoma and immune-mediated diseases such as graft-versus-host disease (GVHD). ECP is thought to control these diseases in part through direct induction of lymphocyte apoptosis, but its effects on the immune system beyond apoptosis remain poorly characterized. We have developed a novel method for incorporating ECP treatment into well-established and clinically relevant murine models of GVHD to examine its effects during an ongoing immune response. We demonstrate that the transfer of cells treated with ECP reverses established GVHD by increasing donor regulatory T cells and indirectly reducing the number of donor effector lymphocytes that themselves had never been exposed to psoralen and ultraviolet A radiation.
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PMID:Extracorporeal photopheresis reverses experimental graft-versus-host disease through regulatory T cells. 1868 79


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