Extracorporeal photopheresis for the prevention of acute GVHD in patients undergoing standard myeloablative conditioning and allogeneic hematopoietic stem cell transplantation

Recent insights into extracorporeal photopheresis for graft-versus-host disease

INTRODUCTION

Extracorporeal Photopheresis (ECP) may be considered the unique large-scale cell therapy currently available. It is currently employed mainly as second-line treatment, especially in steroid-resistant or steroid-dependent Graft versus Host Disease (GvHD) with good results and very few limitations.

AREAS COVERED

Many points need to be clarified regarding the ECP mechanism of action, that conditions the lack of uniqueness among the different centers, essentially cycle frequency, treatment duration, and the number of cells to be treated to obtain a response, according to the organs involved. Moreover, reliable biomarkers for prediction of response are lacking, as well as the best pharmacological combination. We will focus on the recent advances concerning ECP for GvHD treatment. We performed a systematic literature research in Pubmed and Embase as of September 2023.

EXPERT OPINION

The recent studies on ECP mechanism of action along with the promising biomarkers of response, and the synergistic benefit of ECP in association with the new drugs render this therapy an important weapon for GvHD resistant to conventional treatment and can be proposed as a valid first-line therapy option with promising results. We believe that it should be used early in all categories of patients, considering its high safety profile.

Mode of action, indications and recommendations on extracorporeal photopheresis (ECP)

Extracorporeal photopheresis (ECP) has gained importance in the treatment of several diseases. Initially introduced as a new therapeutic modality for the treatment of patients with cutaneous T-cell lymphoma, the indications for the use of ECP have expanded to include hematology and transplantation immunology. Extracorporeal photopheresis has found its place in the treatment plan of cutaneous T-cell lymphoma, systemic sclerosis, graft-versus-host disease, organ transplantation such as heart and lung, sometimes as first-line therapy and very often in combination with various systemic immunosuppressive therapies. The procedure basically consists of three steps: leukapheresis, photoactivation and reinfusion. The following article presents possible theories about the mechanism of action, which is not yet fully understood, and discusses the five most common indications for ECP treatment with corresponding therapy recommendations.

Wirkweise, Indikationen und Therapieempfehlungen der extrakorporalen Photopherese (ECP)

Die extrakorporale Photopherese (ECP) hat in jüngster Zeit bei der Behandlung verschiedener Krankheiten an Bedeutung gewonnen. Ursprünglich als neue Therapie zur Behandlung von Patienten mit kutanem T‐Zell‐Lymphom vorgestellt, hat sich der Indikationsbereich für die ECP auf Hämatologie und Transplantationsimmunologie erweitert. Die ECP hat ihren festen Platz im Therapieplan bei kutanen T‐Zell‐Lymphomen, systemischer Sklerose, Graft‐versus‐Host‐Erkrankung, Organtransplantationen wie Herz und Lunge, teilweise als Erstlinientherapie und sehr häufig in Kombination mit verschiedenen systemischen immunsuppressiven Therapien. Das Verfahren besteht im Wesentlichen aus drei Schritten: Leukapherese, Photoaktivierung und Reinfusion. Im folgenden Artikel werden die noch nicht vollständig verstandenen Wirkmechanismen dargestellt, die fünf häufigsten Indikationen für die Behandlung mit ECP diskutiert und Therapieempfehlungen für die jeweilige Indikation gegeben.

Extracorporeal photopheresis as graft-versus-host disease prophylaxis: a randomized controlled trial: Prophylactic extracorporeal photopheresis to prevent graft-versus-host disease

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative option for many patients diagnosed with hematological malignancies. A major obstacle is graft-versus-host disease (GvHD) causing significant morbidity and mortality. Extracorporeal photopheresis (ECP) is an increasingly applied GvHD treatment, partly due to its favourable safety profile. In contrast, the use of ECP in preventing GvHD is sparse, and randomized controlled trials (RCTs) are lacking.

OBJECTIVE

We therefore conducted a RCT to assess if ECP applied post-transplant, could prevent the development of GvHD within the first year of transplantation.

STUDY DESIGN

We enrolled 157 patients (18-74 years) with a hematological malignancy receiving first allo-HSCT: 76 randomized to the intervention group and 81 to the control group. ECP was initiated directly upon engraftment and was planned twice weekly for two weeks, then once weekly for four weeks. GvHD, relapse, and death were analyzed with Cox regression analysis.

RESULTS

During the first year, 45 patients in the intervention and 52 control patients developed GvHD (HR=0.82, 95% CI 0.55-1.22, P=0.32). There were no differences in acute or chronic GvHD or its organ distribution in this intention-to-treat RCT. A per-protocol analysis revealed a significant difference in GvHD between the intervention (per-protocol; n=39 of 76) and the control group (n=77), 46% vs 68%, respectively, (HR 0.47, 95% CI 0.27-0.80, P=0.006). Relapse occurred in 15 patients in the intervention group and in 11 patients among the controls (HR=1.38, 95% CI 0.64-3.01, P=0.42). GvHD-free relapse-free (GRFS) survival, event-free survival, overall survival and non-relapse mortality did not differ significantly between the two study groups. No significant difference in immune reconstitution between the two study groups was revealed.

CONCLUSION

This first intention-to-treat RCT, investigating ECP as GvHD prophylaxis in allo-HSCT for hematological malignancy does not support the use of ECP as adjunct to standard drug-based GvHD-prophylaxis. This trial was registered at www.

CLINICALTRIALS

gov as #NCT03204721.

[Diagnosis, prophylaxis and therapeutic management of acute GVH: Guidelines from the SFGM-TC]

Acute GVHD is a potentially severe complication of hematopoietic stem cell transplantation, responsible for morbidity and mortality that can affect the prognosis after transplantation. Within the framework of the 12th workshop of practice harmonization of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC), diagnostic modalities of acute GVHD are updated. The conventional prevention (depending on donor, conditioning, and stem cell source) and treatment schemes (depending on affected organ and intensity) of aGVHD are clarified, and new therapeutic options are discussed.

European dermatology forum - updated guidelines on the use of extracorporeal photopheresis 2020 - part 1

Background

Following the first investigational study on the use of extracorporeal photopheresis for the treatment of cutaneous T‐cell lymphoma published in 1983, this technology has received continued use and further recognition for additional earlier as well as refractory forms. After the publication of the first guidelines for this technology in the JEADV in 2014, this technology has maintained additional promise in the treatment of other severe and refractory conditions in a multi‐disciplinary setting. It has confirmed recognition in well‐known documented conditions such as graft‐versus‐host disease after allogeneic bone marrow transplantation, systemic sclerosis, solid organ transplant rejection including lung, heart and liver and to a lesser extent inflammatory bowel disease.

Materials and methods

In order to further provide recognized expert practical guidelines for the use of this technology for all indications, the European Dermatology Forum (EDF) again proceeded to address these questions in the hands of the recognized experts within and outside the field of dermatology. This was done using the recognized and approved guidelines of EDF for this task. All authors had the opportunity to review each contribution as it was added.

Results and conclusion

These updated 2020 guidelines provide at present the most comprehensive available expert recommendations for the use of extracorporeal photopheresis based on the available published literature and expert consensus opinion. The guidelines are divided in two parts: PART I covers cutaneous T‐cell lymphoma, chronic graft‐versus‐host disease and acute graft‐versus‐host disease while PART II will cover scleroderma, solid organ transplantation, Crohn's disease, use of ECP in paediatrics practice, atopic dermatitis, type 1 diabetes, pemphigus, epidermolysis bullosa acquisita and erosive oral lichen planus.

Prognostic factors and long-term follow-up of basiliximab for steroid-refractory acute graft-versus-host disease: Updated experience from a large-scale study

Acute graft-vs-host disease (aGVHD) is one of the most important causes of early mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT), particularly for those with steroid-refractory (SR)-aGVHD. We aimed to identify the prognostic factors and long-term clinical outcomes of basiliximab treatment for SR-aGVHD. Basiliximab was administered on days 1, 3, and 8, and repeated weekly until aGVHD was less than grade II, or patients showed no response after four doses. Out of 1498 patients receiving allo-HSCT, 230 patients with SR-aGVHD were enrolled. Grade III to IV aGVHD before basiliximab treatment significantly and independently predicted a poorer response to basiliximab in multivariate analysis. And, the cumulative incidence of overall response at 14 days, 28 days, and 56 days after treatment was 41.4% vs 23.1% (P = .023), 70.2% vs 43.6% (P = .002), and 80.1% vs 66.7% (P = .013), respectively. This was for those with grade II and grade III to IV aGVHD. Patients receiving more than four doses of basiliximab had higher rates of infections. The 4-year cumulative incidence of total and severe chronic GVHD after basiliximab treatment was 44.8% (95% CI 38.3%-51.3%) and 2.2% (95% CI 0.3%-4.1%), respectively. The 4-year cumulative incidence of relapse, non-relapse mortality, disease-free survival, and overall survival after basiliximab treatment was 11.3% (95% CI 7.2%-15.4%), 30.0% (95% CI 24.1%-35.9%), 58.7% (95% CI 52.3%-65.1%), and 61.7% (95% CI 55.4%-68.0%), respectively. Comorbidities before allo-HSCT and refined Minnesota aGVHD risk score at diagnosis had significant influences on long-term survival. Thus, basiliximab was a safe and effective treatment for patients with SR-aGVHD.

Incorporation of extracorporeal photopheresis into a reduced intensity conditioning regimen in myelodysplastic syndrome and aggressive lymphoma: results from ECOG 1402 and 1902

BACKGROUND

Extracorporeal photopheresis (ECP) is an immunomodulatory cellular therapy which has been shown to induce a tolerogenic state in patients with acute and chronic graft-vs-host disease. ECOG-ACRIN explored the activity of ECP as a part of a reduced intensity conditioning regimen in two multicenter trials in patients with MDS (E1902) and lymphomas (E1402). While both studies closed before completing accrual, we report results in 23 patients (17 MDS and 6 lymphoma).

STUDY DESIGN AND METHODS

Patients received 2 days of ECP followed by pentostatin 4 mg/m2 /day for two consecutive days, followed by 600 cGy of total body irradiation prior to stem cell infusion. Immunosuppression for aGVHD was infusional cyclosporine A or tacrolimus and methotrexate on day +1, +3, with mycophenolate mofetil starting on day 100 for chronic GVHD prophylaxis.

RESULTS

All patients engrafted, with median time to neutrophil and platelet engraftment of 15-18 days and 10-18 days respectively. Grade 3 or 4 aGVHD occurred in 13% and chronic extensive GVHD in 30%.

CONCLUSIONS

These studies demonstrate that ECP/pentostatin/TBI is well tolerated and associated with adequate engraftment of neutrophils and platelets in patients with lymphomas and MDS.

Extracorporeal Photopheresis in Graft-versus-Host Disease

Background and Summary

Extracorporeal photopheresis (ECP) is a leukapheresis-based procedure used in the therapy of acute and chronic graft-versus-host disease (aGvHD, cGvHD) and other diseases. Based on the substantial efficacy and the excellent safety profile in the absence of immunosuppression ECP has established itself as a major treatment form for steroid-refractory GvHD. Here we review the current literature on ECP as a treatment option for patients with aGvHD as well as cGvHD.

Key Messages

ECP is a well-established second-line therapy for cGvHD. Its role in the treatment of aGvHD is less clear but also points towards an effective second-line therapy option. In the future ECP could play a role in the prevention of GvHD. More experimental and randomized controlled trials are needed to define the best patient selection criteria, settings, and therapy regimens for GvHD.

Extracorporeal photopheresis: cellular therapy for the treatment of acute and chronic graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative option for many disease states. Despite significant improvements in strategies used to prevent and treat acute and chronic graft-versus-host disease (a/cGVHD), they continue to negatively affect outcomes of HSCT significantly. Standard, first-line treatment consists of corticosteroids; beyond this, there is little consistency in therapeutic regimens. Current options include the addition of various immunosuppressive agents, the use of which puts patients at even higher risks for infection and other morbidities. Extracorporeal photopheresis (ECP) is a widely used cellular therapy currently approved by the US Food and Drug Administration for use in patients with cutaneous T-cell lymphoma; it involves the removal of peripherally circulating white blood cells, addition of a light sensitizer, exposure to UV light, and return of the cells to the patient. This results in a series of events ultimately culminating in transition from an inflammatory state to that of tolerance, without global immunosuppression or known long-term adverse effects. Large-scale, prospective studies of the use of ECP in patients with a/cGVHD are necessary in order to develop the optimal treatment regimens.

Extracorporeal photopheresis for GVHD prophylaxis after reduced intensity conditioning allogeneic hematopoietic stem cell transplantation: a prospective multicenter phase 2 study

We performed a prospective multicenter phase 2 study to evaluate the safety and efficacy of prophylactic Extracorporeal Photopheresis (ECP) in adult patients with hematological malignancies early after RIC allo-HSCT on day 21 twice per week during the first two weeks and then once per week for the next four weeks for a total of eight ECP courses. A total of 20 patients were included; 10 were males, median age was 60 years. All patients engrafted, 17 (85%) received the total eight ECP courses. There were no adverse effects related to ECP. Seven patients developed acute graft-versus-host disease (GVHD), with 15% grade ≥ II cumulative incidence at day 100. The cumulative incidence of chronic GVHD at 2 years was 22%. The 2 years probability of overall survival (OS) and progression-free survival (PFS) were 84 and 74%, respectively. This study shows encouraging results with low acute and chronic GVHD incidence and no interference with graft-versus-leukemia (GVL) effect.

Chronic lung allograft dysfunction: evolving practice

PURPOSE OF REVIEW

Chronic lung allograft dysfunction (CLAD) was recently introduced as an overarching term covering different phenotypes of chronic allograft dysfunction, including obstructive CLAD (bronchiolitis obliterans syndrome), restrictive CLAD (restrictive allograft syndrome) and graft dysfunction due to causes not related to chronic rejection. In the present review, we will highlight the latest insights and current controversies regarding the new CLAD terminology, underlying pathophysiologic mechanisms, diagnostic approach and possible treatment options.

RECENT FINDINGS

Different pathophysiological mechanisms are clearly involved in clinically distinct phenotypes of chronic rejection, as is reflected by differences in histology, allograft function and imaging. Therefore, not all CLAD patients may equally benefit from specific therapies.

SUMMARY

The recent introduction of CLAD importantly changed the clinical practice in lung transplant recipients. Given the relative low accuracy of the current diagnostic tools, future research should focus on specific biomarkers, more sensitive pulmonary function parameters and imaging techniques for timely CLAD diagnosis and phenotyping. Personalized or targeted therapeutic options for adequate prevention and treatment of CLAD are required.

A concise review on extracorporeal photochemotherapy: Where we began and where we are now and where are we going!

Currently, more than 1080 peer-reviewed papers are displayed on PubMed when initiating a search for therapeutic indications and mechanisms of action of extracorporeal photochemotherapy (ECP). This concise review focuses mainly on some prevalent and traditional treatment-resistant disorders with an emphasis on immunologic complications emerging from stem cell and solid organ transplantation.

Extracorporeal photopheresis in prevention and treatment of acute GVHD

Acute graft versus host disease (GVHD), a common complication after allogeneic hematopoietic cell transplantation (HCT), occurs in as many as 70% of recipients of this life saving treatment. Front line therapy for GVHD with corticosteroids will fail in up to 40% of patients, which leads to high morbidity and mortality. Traditional prevention and treatment strategies have focused on reducing alloreactivity, typically with therapy to reduce cytotoxic T-cell function. Emerging evidence exists that promotion of regularly T-cell function, through treatments such as extracorporeal photopheresis, is effective for GVHD treatment and has potential for prevention as well. This review will focus on literature reporting the success of ECP for steroid refractory acute GVHD and the potential for delivery of ECP in the early pre and post-transplant periods that shows promise as a less immunosuppressive strategy to reduce rates of acute GVHD.

Guidelines on the use of extracorporeal photopheresis

BACKGROUND

After the first investigational study on the use of extracorporeal photopheresis for the treatment of cutaneous T-cell lymphoma was published in 1983 with its subsequent recognition by the FDA for its refractory forms, the technology has shown significant promise in the treatment of other severe and refractory conditions in a multi-disciplinary setting. Among the major studied conditions are graft versus host disease after allogeneic bone marrow transplantation, systemic sclerosis, solid organ transplant rejection and inflammatory bowel disease.

MATERIALS AND METHODS

In order to provide recognized expert practical guidelines for the use of this technology for all indications the European Dermatology Forum (EDF) proceeded to address these questions in the hands of the recognized experts within and outside the field of dermatology. This was done using the recognized and approved guidelines of EDF for this task.

RESULTS AND CONCLUSION

These guidelines provide at present the most comprehensive available expert recommendations for the use of extracorporeal photopheresis based on the available published literature and expert consensus opinion.

Extracorporeal photopheresis (photochemotherapy) in the treatment of acute and chronic graft versus host disease: immunological mechanisms and the results from clinical studies

Extracorporeal photopheresis (ECP) is an immunomodulatory alternative for treatment of graft versus host disease (GVHD). The blood is then separated into its various components through apheresis; buffy coat cells are thereafter treated with 8-methoxypsoralen before exposure to ultraviolet light and finally reinfused into the patient. There is a general agreement that this treatment has an anti-GVHD effect, but the mechanisms of action behind this effect are only partly understood. However, altered maturation of dendritic cells (DC) and thereby indirect modulation of T-cell reactivity seems to be one important mechanism together with DC-presentation of antigens derived from apoptotic donor T cells and induction of regulatory T cells. The treatment has been best studied in patients with chronic GVHD (both pediatric and adult patients), but most studies are not randomized and it is difficult to know whether the treatment is more effective than the alternatives. The clinical studies of ECP in adults with acute GVHD are few and not randomized; it is not possible to judge whether this treatment should be a preferred second- or third-line treatment. There is no evidence for increased risk of leukemia relapse or suppression of specific graft versus leukemia reactivity by this treatment, so specific antileukemic immunotherapy may still be possible. Thus, even though the treatment seems effective in patients with GVHD, further clinical (especially randomized) as well as biological studies with careful standardization of the treatment are needed before it is possible to conclude how ECP should be used in acute and chronic GVHD.

Autologous apoptotic cells preceding transplantation enhance survival in lethal murine graft-versus-host models

Acute graft-versus-host disease (GVHD) is induced by alloreactivity of donor T cells toward host antigens presented on antigen-presenting cells (APCs). Apoptotic cells are capable of inducing tolerance by altering APC maturation. Apoptosis can be induced by extracorporeal photopheresis (ECP). We demonstrate that the use of ECP as a prophylaxis prior to conditioning significantly improves survival (P < .0001) after bone marrow transplantation (BMT) by inhibiting the initiation phase of acute GVHD in a murine BMT model. ECP-treated autologous splenocytes resulted in immune tolerance in the host, including reduced dendritic cell activation with decreased nuclear factor-κB engagement, increased regulatory T-cell (Treg) numbers with enhanced expression of cytolytic T lymphocyte-associated antigen 4, potentiating their suppressive function. The protective effect required host production of interleukin-10 and host Tregs. Conventional T cells that entered this tolerant environment experienced reduced proliferation, as well as a reduction of tissue homing and expression of activation markers. The induction of this tolerant state by ECP was obviated by cotreatment with lipopolysaccharide, suggesting that the inflammatory state of the recipient prior to treatment would play a role in potential clinical translation. The use of prophylactic ECP may provide an alternative and safe method for immunosuppression in the bone marrow transplant setting.

Extracorporeal photopheresis: a useful therapy for patients with steroid-refractory acute graft-versus-host disease but not for the prevention of the chronic form

BACKGROUND

Extracorporeal photopheresis (ECP) has been used successfully to treat severe steroid-refractory acute and chronic graft-versus-host disease (aGVHD, cGVHD) since the late 1990s.

OBJECTIVES

To evaluate retrospectively the efficacy and safety of ECP in patients with aGVHD. We also assessed whether ECP may play a role in the prevention of cGVHD.

PATIENTS AND METHODS

Nine consecutive patients with allografts with aGVHD grade II-III, as defined by consensus criteria, and refractory to steroids, were treated with ECP. ECP was started at a median interval of 46·3 days (range 10-70) from aGVHD onset. Patients were treated initially on two consecutive days (one cycle) at 1-week intervals until improvement and then every 2 weeks. Treatment was then tapered off individually. To evaluate statistical relationships with outcome after 30, 60 and 90 days of ECP, all clinical and historical variables of the patients before treatment were analysed.

RESULTS

All patients survived and responded within 90 days. The average aGVHD score was 1·72 at aGVHD onset, 2·44 when ECP was started and then gradually declined to 0·44 on day 90. At the same time, the average dose of methylprednisolone declined from 2·22 mg kg(-1) to 0·27 mg kg(-1) (day 90), while the average dose of ciclosporin declined from 2·46 mg kg(-1) to 0·77 mg kg(-1) (day 90). Six of nine patients showed a complete skin response after 90 days of treatment. All patients with liver and gastrointestinal tract involvement had complete responses after 90 days, apart from one patient. All our patients developed cGVHD, seven of nine while still on maintenance regimen (6-13 months after haematopoietic stem cell transplantation, HSCT) and the other two patients after suspension of ECP (6 and 9 months after HSCT).

CONCLUSIONS

ECP is effective in patients with mild to moderate steroid-refractory aGVHD (grade II-III). On the other hand, ECP did not prevent the development of cGVHD in our patients.

Acute graft-versus-host disease: are we close to bringing the bench to the bedside?

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplant (AHSCT) associated with significant morbidity and mortality. This review focuses on the pathophysiology, prevention, and treatment of acute GVHD. Specifically, we explain how new discoveries in immunology have expanded our understanding of GVHD, in which tissue damage from chemotherapy or radiation results in cytokine release, activating T cells, resulting in proliferation and differentiation, trafficking to target organs, and tissue destruction and inflammation. Insights into the mechanisms of this disease relate directly to the development of preventive strategies and therapies, such as immunosuppression, calcineurin inhibitors, T-cell depletion, CCR5 antagonists, gut decontamination, extracorporeal photopheresis, and more. Understanding the immunobiology of GVHD and developing effective preventions and treatments are critical to the continuing success of AHSCT.

Concise review: acute graft-versus-host disease: immunobiology, prevention, and treatment

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplant (AHSCT) associated with significant morbidity and mortality. This review focuses on the pathophysiology, clinical features, prevention, and treatment of acute GVHD. Specifically, we explain how new discoveries in immunology have expanded our understanding of GVHD, in which tissue damage from chemotherapy or radiation results in cytokine release, which activates T cells, resulting in proliferation and differentiation, trafficking to target organs, and tissue destruction and inflammation. Insights into the mechanisms of this disease relate directly to the development of preventive strategies and therapies, such as immunosuppression, T-cell depletion, calcineurin inhibitors, CCR5 antagonists, gut decontamination, extracorporeal photopheresis, and more. We also discuss how GVHD affects the gut, liver, and skin, as well as diagnosis, grading, and scoring. We end by examining future directions of treatment, including new immunomodulators and biomarkers. Understanding the immunobiology of GVHD and developing effective preventions and treatments are critical to the continuing success of AHSCT.

Prevention of graft-vs.-host disease

INTRODUCTION

Allogeneic hematopoietic cell transplantation (HCT) is a curative treatment for many malignant and non-malignant hematologic disorders. However, graft-vs.-host disease (GVHD) remains a major complication of allogeneic HCT and limits the success of this approach.

AREAS COVERED

This paper reviews recent developments in the prevention of acute and chronic GVHD. In the setting of acute GVHD prevention, recent trials of T-cell depletion using Fresenius-ATG are reviewed, as well as studies testing total lymphoid irradiation, mesenchymal stromal cells, rituximab, statins, sirolimus and other investigational agents. In the setting of chronic GVHD, results with Fresenius-ATG are reviewed, as well as B-cell depletion with rituximab, and the potential role of the B-cell regulatory cytokine BAFF in chronic GVHD is also discussed. Finally, the emerging role of resident skin and gut bacterial flora-the so-called microbiome-in the pathogenesis of GVHD is covered.

EXPERT OPINION

Current methods of acute GVHD prevention are highly successful, and a number of investigational approaches promise to further reduce the risk of this complication. By contrast, chronic GVHD is more poorly understood and more difficult to prevent. Future studies are required to delineate the roles of these approaches and to abrogate GVHD without sacrificing the beneficial immunologic graft-vs.-tumor effect.

Have we improved in preventing and treating acute graft-versus-host disease?

PURPOSE OF REVIEW

Acute graft-versus-host disease (GVHD) is a considerable source of morbidity and mortality following allogeneic hematopoietic cell transplantation (HCT). Accordingly, progress in the prevention and primary therapy of this complication is needed to improve patient outcomes.

RECENT FINDINGS

Guided by insights into acute GVHD pathogenesis, investigators have explored novel cellular and pharmacologic approaches to acute GVHD prevention that demonstrates promise. Although pan-T-cell depletion has reduced GVHD, novel strategies that selectively deplete alloreactive T cells or modulate the balance of effector T cells and regulatory T cells offer promise to selectively abrogate acute GVHD while retaining protection from primary disease relapse and infectious complications.

SUMMARY

Divergent approaches in the primary therapy of acute GVHD have explored both combination approaches with standard dose glucocorticoids and additional immunosuppressive agents and conversely steroid-sparing approaches including topical agents such as beclomethasone or sirolimus as a steroid-free approach to acute GVHD therapy. Mature results of high-quality clinical trials are needed to determine the optimal therapy that results in effective control of the syndrome and limited toxicity. These complementary outcomes represent the therapeutic goal for future investigation in acute GVHD therapy.

Extracorporeal photopheresis attenuates murine graft-versus-host disease via bone marrow-derived interleukin-10 and preserves responses to dendritic cell vaccination

Extracorporeal photopheresis (ECP) is emerging as a therapy for graft-versus-host-disease (GVHD), but the full mechanism of action and the impact on immunity have not been fully established. After murine minor histocompatibility antigen-mismatched bone marrow (BM) transplantation (allo-BMT), coinfusion of ECP-treated splenocytes with T cell-replete BM attenuated GVHD irrespective of the donor strain of the ECP-treated splenocytes, and was associated with increased numbers of regulatory T cells. Coculture of myeloid dendritic cells (DCs) with ECP-treated splenocytes resulted in increased interleukin (IL)-10 production after submaximal stimulation with lipopolysaccharide. Furthermore, male myeloid DCs exposed to ECP-treated splenocytes were less potent at inducing CD8(+) HY responses when used as a vaccine in vivo. The efficacy of ECP-treated splenocytes was enhanced when administered just before delayed donor lymphocyte infusion following T cell-depleted allo-BMT, allowing for the administration of sufficient numbers of T cells to respond to myeloid DC vaccination in the absence of a thymus. Finally, the therapeutic effect of ECP-treated splenocytes was lost in recipients of IL-10-deficient BM. We demonstrate that ECP-treated splenocytes attenuate GVHD irrespective of the source of ECP-treated cells via a mechanism that likely involves modulation of DCs and requires IL-10 produced by BM-derived cells. Importantly, the attenuation of GVHD by ECP-treated splenocytes permits donor lymphocyte infusion-dependent responses to DC vaccines after allo-BMT.