Extracorporeal photopheresis reverses experimental graft-versus-host disease through regulatory T cells

Role of extracorporeal photopheresis in the management of acute and chronic graft versus disease: current status

Extracorporeal photopheresis (ECP) is a therapy that combines the collection of mononuclear cells by apheresis, the addition of a photosensitizer (8-methoxisoralen), the illumination of the product with ultraviolet A light, and the immediate infusion of the product to the patient. Initially developed and approved to treat T-cell cutaneous lymphomas, soon started to be used to treat graft versus host disease (GvHD) developed after allogeneic hematopoietic-cell transplantation. The high response rate of ECP in skin, ocular, oral, pulmonary, and liver forms of chronic GvHD, the steroid-sparing effect, and the improved overall survival of treated patients, made ECP one of the second-line treatments used to treat steroid-resistant acute and chronic GVHD. Recently, the development of new drugs for treating GVHD has changed the position of ECP in the therapy of GVHD and has started to be used in combination with drugs for increasing the response rate to the treatment in severe or resistant forms of acute and chronic GVHD. ECP remains an essential therapeutic resource in the management of patients with refractory acute and chronic GVHD.

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.

Extracorporeal photopheresis reduces inflammation and joint damage in a rheumatoid arthritis murine model

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammatory reactions and tissue damage in the joints. Long-term drug use in clinical practice is often accompanied by adverse reactions. Extracorporeal photopheresis (ECP) is an immunomodulatory therapy with few side effects, offering a potential and safe therapeutic alternative for RA through the induction of immune tolerance. This study aimed to investigate the therapeutic effects of ECP on RA using a collagen-induced arthritis (CIA) murine model, as well as to explore its immunomodulatory effects in vivo. Additionally, particular attention was given to the significant role of monocytes during the ECP process.

METHODS

A murine model of rheumatoid arthritis was established by administering two injections of bovine type II collagen to DBA/1J mice. ECP, ECP-MD (mononuclear cells were depleted during the ECP), MTX, and PBS treatment were applied to the CIA mice. During the treatment process, clinical scores and body weight changes of CIA mice were closely monitored. After six treatment sessions, micro-CT images of the hind paws from live mice were captured. Ankle joints and paws of the mice were collected and processed for histological evaluation. Spleen samples were collected to measure the Th17/Treg cells ratio, and serum samples were collected to assess cytokine and anti-type II collagen IgG levels. Monocytes and dendritic cells populations before and after ECP in vitro were detected by flow cytometry.

RESULT

ECP therapy significantly attenuated the progression of CIA, alleviated the severity of clinical symptoms in CIA mice and effectively suppressed synovial hyperplasia, inflammation, and cartilage damage. There was an expansion in the percentage of CD3 + CD4 + CD25 + FoxP3 + Tregs and a decrease in CD3 + CD4 + IL17A + Th17 cells in vivo. Furthermore, ECP reduced the serum levels of pro-inflammatory cytokines IL-6 (53.47 ± 7.074 pg/mL vs 5.142 ± 1.779 pg/mL, P < 0.05) and IL-17A (3.077 ± 0.401 pg/mL vs 0.238 ± 0.082 pg/mlL, P < 0.0001) compared with PBS. Interestingly, the depletion of monocytes during the ECP process did not lead to any improvement in clinical symptoms or histological scores in CIA mice. Moreover, the imbalance in the Th17/Treg cells ratio became even more pronounced, accompanied by an augmented secretion of pro-inflammatory cytokines IL-6 and IL-17A. In vitro, compared with cells without ECP treatment, the proportion of CD11b + cells were significantly reduced (P < 0.01), the proportion of CD11c + cells were significantly elevated (P < 0.001) 24 h after ECP treatment. Additionally, the expression of MHC II (P < 0.0001), CD80 (P < 0.01), and CD86 (P < 0.001) was downregulated in CD11c + cells 24 h after ECP treatment.

CONCLUSION

Our study demonstrates that ECP exhibits a therapeutic effect comparable to conventional therapy in CIA mice, and the protective mechanisms of ECP against RA involve Th17/Treg cells ratio, which result in decreased IL-6 and IL-17A. Notably, monocytes derived from CIA mice are an indispensable part to the efficacy of ECP treatment, and the proportion of monocytes decreased and the proportion of tolerogenic dendritic cells increased after ECP treatment in vitro.

Collection efficiency of mononuclear cells in offline extracorporeal photopheresis: can processing time be shortened?

BACKGROUND

Extracorporeal photopheresis (ECP) is a well-established but lengthy and burdensome cell-based therapy for various diseases such as cutaneous T-cell lymphoma, graft-versus-host disease and organ rejection after transplantation. The number of mononuclear cells (MNCs) that needs to be collected to obtain a clinical response to ECP is still under debate. The purpose of this retrospective study was to determine the number of lymphocytes, monocytes and neutrophils in mononuclear cell products (MCP) by flow cytometry and the collection efficiency in the offline ECP setting.

MATERIALS AND METHODS

We collected data from 10 different patients undergoing 162 ECP procedures using the Spectra Optia device for MNC collection. White blood cell (WBC) count of MCP was determined using a hematology analyzer. MNCs were analyzed for CD45 and CD14 expression by flow cytometry to exactly determine the collected lymphocyte and monocyte fractions.

RESULTS

Collected MCP showed high cell yields with 55.3×106/kg MNCs and 41.1×106/kg lymphocytes. MCP were characterized by high MNC (81.3%) and low neutrophils (18.7%) percentage. Mean collection efficiency for WBCs and for MNCs was 23.9% and 62.0%, respectively. The MNC fraction showed a moderate to high correlation between peripheral blood cell count of patients and MCP count.

DISCUSSION

This study is one of a few reports showing the monocyte-to-lymphocyte relation in MCP for ECP determined by flow cytometry. In comparison to historical data from inline ECP, the offline ECP processing one total blood volume results in considerably higher cell yields. For this reason, and to reduce the burden on patients, we propose that the offline ECP processing time can be substantially reduced.

Apoptotic bodies inhibit inflammation by PDL1-PD1-mediated macrophage metabolic reprogramming

Apoptosis triggers immunoregulation to prevent and suppress inflammation and autoimmunity. However, the mechanism by which apoptotic cells modulate immune responses remains largely elusive. In the context of allogeneic mesenchymal stem cells (MSCs) transplantation, long-term immunoregulation is observed in the host despite the short survive of the injected MSCs. In this study, utilizing a mouse model of acute lung injury (ALI), we demonstrate that apoptotic bodies (ABs) released by transplanted human umbilical cord MSCs (UC-MSCs) convert the macrophages from a pro-inflammatory to an anti-inflammatory state, thereby ameliorating the disease. Mechanistically, we identify the expression of programmed cell death 1 ligand 1 (PDL1) on the membrane of UC-MSCs-derived ABs, which interacts with programmed cell death protein 1 (PD1) on host macrophages. This interaction leads to the reprogramming of macrophage metabolism, shifting from glycolysis to mitochondrial oxidative phosphorylation via the Erk-dependent pathway in ALI. Importantly, we have reproduced the PDL1-PD1 effects of ABs on metabolic switch using alveolar macrophages from patients with ALI, suggesting the potential clinical implications of developing therapeutic strategies for the patients.

Extracorporeal Photopheresis in Graft-versus-Host Disease

Graft-versus-host disease (GVHD) is a major cause of mortality and morbidity following allogeneic hematopoietic stem cell transplantation. Extracorporeal photopheresis (ECP), which exposes mononuclear cells to ultraviolet A irradiation in the presence of a photosensitizing agent, has shown efficacy in the treatment of GVHD. Recent observations in molecular and cell biology have revealed the mechanisms by which ECP can reverse GVHD, including lymphocyte apoptosis, differentiation of dendritic cells from circulating monocytes, and modification of the cytokine profile and T cell subpopulations. Technical innovations have made ECP accessible to a broader range of patients; however, logistical constraints may limit its use. In this review, we scrutinize the development of ECP from its origins to recent insights into the biology underlying ECP efficacy. We also review practical aspects that may complicate successful ECP treatment. Finally, we analyze how these theoretical concepts translate into clinical practice, summarizing the published experiences of leading research groups worldwide.

Conventional and Novel Approaches to Immunosuppression in Lung Transplantation

Most therapeutic advances in immunosuppression have occurred over the past few decades. Although modern strategies have been effective in reducing acute cellular rejection, excess immunosuppression comes at the price of toxicity, opportunistic infection, and malignancy. As our understanding of the immune system and allograft rejection becomes more nuanced, there is an opportunity to evolve immunosuppression protocols to optimize longer term outcomes while mitigating the deleterious effects of traditional protocols.

Multidisciplinary Approach to the Diagnosis and Therapy of Mycosis Fungoides

Mycosis fungoides is the most common primary cutaneous T-cell lymphoma, characterized by skin-homing CD4+ T cells derivation, indolent course, and low-grade of malignancy. Mycosis fungoides's classic type typically onsets with cutaneous erythematous patches, plaque, and tumor. In WHO-EORTC classification, folliculotropic mycosis fungoides, pagetoid reticulosis, and granulomatous slack skin are recognized as distinct variants of mycosis fungoides, because of their clinical and histological features, behavior, and /or prognosis. Mycosis fungoides often shows diagnostic difficulties, due to its absence of specific features and lesional polymorphism. A patient's treatment requires staging. In about 10% of cases, mycosis fungoides can progress to lymph nodes and internal organs. Prognosis is poor at advanced stage and management needs a multidisciplinary team approach. Advanced stage disease including tumors, erythroderma, and nodal, visceral, or blood involvement needs skin directed therapy associated with systemic drugs. Skin directed therapy includes steroids, nitrogen mustard, bexarotene gel, phototherapy UVB, and photochemiotherapy, i.e., total skin electron radiotherapy. Systemic therapies include retinoids, bexarotene, interferon, histone deacetylase inhibitors, photopheresis, targeted immunotherapy, and cytotoxic chemotherapy. Complexity of mycosis fungoides associated with long-term chronic evolution and multiple therapy based on disease stage need a multidisciplinary team approach to be treated.

Extracorporeal Photopheresis Improves Graft Survival in a Full-Mismatch Rat Model of Kidney Transplantation

Extracorporeal photopheresis (ECP) is an immunomodulatory therapy based on the infusion of autologous cellular products exposed to ultraviolet light (UV) in the presence of a photosensitizer. The study evaluates the ECP efficacy as induction therapy in a full-mismatch kidney transplant rat model. Dark Agouti to Lewis (DA-L) kidney transplant model has been established. ECP product was obtained from Lewis rat recipients after DA kidney graft transplantation (Lew^DA). Leukocytes of those Lew^DA rats were exposed to 8-methoxy psoralen, and illuminated with UV-A. The ECP doses assessed were 10 × 10⁶ and 100 × 10⁶ cells/time point. Lewis recipients received seven ECP infusions. DA-L model was characterized by the appearance of donor-specific antibodies (DSA) and kidney function deterioration from day three after kidney transplant. The dysfunction progressed rapidly until graft loss (6.1 ± 0.5 days). Tacrolimus at 0.25 mg/kg prolonged rat survival until 11.4 ± 0.7 days (p = 0.0004). In this context, the application of leukocytes from LewDA sensitized rats accelerated the rejection (8.7 ± 0.45, p = 0.0012), whereas ECP product at high dose extended kidney graft survival until 26.3 ± 7.3 days, reducing class I and II DSA in surviving rats. ECP treatment increases kidney graft survival in full-mismatch rat model of acute rejection and is a suitable immunomodulatory therapy to be explored in kidney transplantation.

Extracorporeal photopheresis as an immunomodulatory treatment modality for chronic GvHD and the importance of emerging biomarkers

Haematopoietic stem cell transplantation (HSCT) is the treatment of choice for malignant haematological diseases. Despite continuous improvements in pre- and post-transplantation procedures, the applicability of allo-HSCT is limited by life-threatening complications such as graft-versus-host disease (GvHD), engraftment failure, and opportunistic infections. Extracorporeal photopheresis (ECP) is used to treat steroid resistant GvHD with significant success. However, the molecular mechanisms driving its immunomodulatory action, whilst preserving immune function, require further understanding. As ECP is safe to administer with few significant adverse effects, it has the potential for earlier use in the post-HSCT treatment of GvHD. Thus, further understanding the immunomodulatory mechanisms of ECP action may justify more timely use in clinical practice, as well as identify biomarkers for using ECP as first line or pre-emptive GvHD therapy. This review aims to discuss technical aspects and response to ECP, review ECP as an immunomodulatory treatment modality for chronic GvHD including the effect on regulatory T cells and circulating vs. tissue-resident immune cells and consider the importance of emerging biomarkers for ECP response.

Extracorporeal photopheresis for the treatment of chronic graft versus host disease

OBJECTIVES

Chronic graft versus host disease (chronic GVHD) still remains the leading cause of late morbidity and mortality for allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. In this retrospective study, 53 consecutive allo-HSCT patients with chronic GVHD refractory to corticosteroids were treated with extracorporeal photopheresis (ECP).

METHODS

This study was performed as a retrospective single-center study. Medical records of a total of 59 patients treated with ECP for chronic GVHD were reviewed.

RESULTS

Best organ responses to ECP were observed in skin, mouth mucosa, eyes and liver. Overall response rate (ORR) to ECP was 81.2% (CR 17% and PR 64.2%). Overall survival (OS) was 84.9% and 36.7%, at 1 and 3 years, respectively. Female sex appears to have an advantage on ORR. Patients achieving ORR were able to maintain their responses with a prolonged continuation of treatments for +6 and +12 months indicating the benefits of longer ECP treatment.

DISCUSSION

We found that patients with chronic GVHD who were treated with ECP for 12 months or longer had a higher response rate. Our findings in line with the data reported previously suggest that patients responding to ECP should continue longer therapy schedules to achieve a better and sustained response. In our cohort, long-term ECP therapy was safe and well-tolerated with no significant adverse effects. Best responses were observed in the patients with skin, eye, liver and oral involvement. The ECP procedure offers the advantage relative to the problems with typical immunosuppressive agents. The female sex appeared to have an advantage based on the cumulative probability of the OR after ECP for chronic GVHD.

Efficacy of a 365 nm Ultraviolet A1 light Emitting Diode (UVA1-LED) in in vitro Extracorporeal Photopheresis

Extracorporeal photochemotherapy (ECP) is one of the more effective cell therapies for graft-versus-host disease (GvHD). ECP is a widely recommended therapeutic approach for the treatment of chronic GvHD, particularly steroid-refractory GVHD. In recent years, the use of a light emitting diode (LED) in the clinic has attracted considerable interest. In this study, we examined the issue of whether an ultraviolet A1-light emitting diode (UVA1-LED) can be used as a light source in ECP. To compare the efficacy of ECP with conventional UVA lamp and a UVA1-LED, we established an in vitro ECP model. Treatment efficacy was evaluated by measuring the % apoptosis and the inhibition of T-cell proliferation. To investigate the effect of ECP on the innate immune reaction, THP-1 cells with a luciferase reporter gene driven by a NF-kB response element (THP-1 luc NF-kB) were treated with ECP. The LED-ECP induced apoptosis and inhibition of T-cell proliferation as efficiently as a conventional ECP. However, LED-ECP induced less innate immunity in THP-1. Since LED devices are more compact compared with conventional UVA irradiation devices, the use of a UVA1-LED in the treatment of ECP may be a better alternative to conventional ECP therapy.

A Prospective, Multicenter Study of Closed System Extracorporeal Photopheresis for Children With Steroid-Refractory Acute Graft-Versus-Host Disease

BACKGROUND

Steroid-refractory (SR) acute graft-versus-host disease (aGvHD) therapy involves intensive immunosuppression, which is associated with significant infectious risk. Extracorporeal photopheresis (ECP) is used to treat SR-aGvHD and is considered to be more immunomodulatory than immunosuppressive. However, pediatric data are mostly retrospective and often involve multi-step ECP that includes apheresis followed by separate photosensitizing/reinfusion on another device.

OBJECTIVE

To prospectively evaluate the efficacy and safety of a single-device ECP system in children with SR-aGvHD.

STUDY DESIGN

Open-label, multicenter, phase 3 study of the THERAKOS® CELLEX® Photopheresis System in children/young adults aged 1 to 21 years with SR-aGvHD. Patients were treated 3 times per week for 4 weeks, then twice weekly through week 12 while maintaining standard aGvHD prophylaxis. The primary efficacy endpoint was the proportion of patients achieving overall response (OR) at day 28 without the addition of next-line systemic treatment. Secondary endpoints included the proportion of patients achieving OR at weeks 8 and 12; the mean weekly steroid dose at weeks 4, 8, and 12; and treatment-emergent adverse events (TEAEs).

RESULTS

Twenty-nine children (median age, 8 years) were enrolled. OR was 55% by day 28, 74% by week 8, and 79% by week 12. Progressive improvements were observed in the skin and the gastrointestinal tract. Mean steroid dose decreased from 1.54 mg/kg/day at baseline to 0.90 mg/kg/day at week 4; 35% of patients achieved >50% steroid dose reduction at week 4 and 75% achieved >50% steroid dose reduction at week 12. Of 168 TEAEs reported among 25 patients (86%), 28 (17%) events were infections and 14 (8%) events were considered to be probably treatment related (all nonserious). Of 627 ECP treatments administered in children/young adults, 68% required blood priming. Treatment-related AEs, including hypotension, hypocalcemia, central line infection, and catheter-site bruising, were rare (1 event each). Three deaths occurred and were deemed unrelated to ECP by the investigators.

CONCLUSION

Use of the THERAKOS® CELLEX® Photopheresis System was effective in children with SR-aGvHD, with more than half experiencing improvement by day 28 and further responses observed over 12 weeks. Very few TEAEs were attributable to ECP, and no new safety signals were observed.

Extracorporeal photopheresis in acute and chronic steroid‑refractory graft-versus-host disease: an evolving treatment landscape

Patients with steroid-refractory graft-versus-host disease (GvHD) are known to have a poor prognosis and for decades no approved drug has been available to treat this serious condition. Although ruxolitinib, a selective Janus kinase (JAK)1/2 inhibitor demonstrated significantly higher response rates in randomized trials compared to the best available therapy, and thus, is of benefit in both acute as well as chronic GvHD, there is an urgent medical need to improve results, such as durability of responses, response in eye, liver and lung manifestations and reduction of infectious complications. In this "Review" article we would like to offer strategies for improving treatment results in patients with steroid-refractory GvHD by combining ruxolitinib with extracorporeal photopheresis (ECP), a leukapheresis-based immunomodulatory treatment frequently applied in T-cell mediated immune disease including GvHD. Our article explores key published evidence supporting the clinical efficacy of both ruxolitinib and ECP in the treatment of GvHD and highlights their potentially complementary mechanisms of action.

Extracorporeal photopheresis in the treatment of acute graft-versus-host disease: A multicenter experience

BACKGROUND AND OBJECTIVES

Extracorporeal photopheresis (ECP) is one of the second-line treatment strategies in steroid-refractory acute graft-versus-host disease (aGvHD). We aimed to share our multicenter experience using ECP in our steroid-refractory aGvHD patients.

MATERIALS AND METHODS

A retrospective observational series of 75 aGvHD patients from 4 transplant centers were analyzed. All ECP procedures were performed with the off-line system. All patients received ECP as second-line therapy.

RESULTS

74.7 % of aGvHD patients were grade 3 or 4. The overall response rate was 42.7 % (32/75) in aGvHD including 17 complete responses (22.7 %). Median follow-up was 6 months (range, 1-68). Median overall survival (OS) was 5 months for non-responders and 68 months for responders (p < 0.001). Twenty-seven (36 %) patients are alive, and 48 (64 %) patients have died.

CONCLUSIONS

Early initiated ECP could be an effective treatment alternative in patients with steroid-refractory aGvHD.

Immunomodulatory Therapies for the Treatment of Graft-versus-host Disease

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is a potentially curative therapy for patients suffering from hematological malignancies, and its therapeutic success is based on the graft-versus-leukemia (GvL) effect. Severe acute and chronic graft-versus-host disease (GvHD) are life-threatening complications after allo-HCT. To date, most of the approved treatment strategies for GvHD rely on broadly immunosuppressive regimens, which limit the beneficial GvL effect by reducing the cytotoxicity of anti-leukemia donor T-cells. Therefore, novel therapeutic strategies that rely on immunomodulatory rather than only immunosuppressive effects could help to improve patient outcomes. Treatments should suppress severe GvHD while preserving anti-leukemia immunity. New treatment strategies include the blockade of T-cell activation via inhibition of dipeptidyl peptidase 4 and cluster of differentiation 28-mediated co-stimulation, reduction of proinflammatory interleukin (IL)-2, IL-6 and tumor necrosis factor-α signaling, as well as kinase inhibition. Janus kinase (JAK)1/2 inhibition acts directly on T-cells, but also renders antigen presenting cells more tolerogenic and blocks dendritic cell-mediated T-cell activation and proliferation. Extracorporeal photopheresis, hypomethylating agent application, and low-dose IL-2 are powerful approaches to render the immune response more tolerogenic by regulatory T-cell induction. The transfer of immunomodulatory and immunosuppressive cell populations, including mesenchymal stromal cells and regulatory T-cells, showed promising results in GvHD treatment. Novel experimental procedures are based on metabolic reprogramming of donor T-cells by reducing glycolysis, which is crucial for cytotoxic T-cell proliferation and activity.

Tolerance, immunosuppression, and immune modulation: impacts on lung allograft survival

PURPOSE OF REVIEW

Immune responses following lung transplantation continue to result in high rates of allograft failure and rejection, and current immunosuppression does not address the unique immunologic properties of the lung. Here, we review recent studies on lung allograft tolerance and alloimmunity and discuss implications for immunosuppression.

RECENT FINDINGS

Processes governing tolerance and alloimmunity in lung allografts differ from other solid organs. Recent studies have suggested that allorecognition is regulated at the level of the lung graft. Furthermore, certain cell populations essential for lung allograft tolerance may facilitate rejection in other organs. Induction of lung allograft tolerance is associated with the formation of tertiary lymphoid organs, which are enriched in regulatory T cells and play an important role in preventing rejection.

SUMMARY

Recent discoveries regarding alloactivation and the regulation of tolerance following lung transplantation have introduced exciting potential avenues for the development of lung-specific immunosuppression.

Thymopoiesis, Alterations in Dendritic Cells and Tregs, and Reduced T Cell Activation in Successful Extracorporeal Photopheresis Treatment of GVHD

Acute graft-versus-host disease (aGVHD) is a significant complication of allogeneic hematopoietic stem cell transplant (HSCT) and negatively affects T cell reconstitution. Extracorporeal photopheresis (ECP) reduces aGVHD, but the mechanisms remain incompletely understood. Our objective was to examine the impact of ECP on thymopoiesis in pediatric aGVHD and the mechanisms at a cellular and transcriptional level. Sixteen pediatric HSCT patients were recruited: 6 with ECP-treated aGVHD, 5 without aGVHD, and 5 with aGVHD treated with corticosteroids only. Thymopoiesis was evaluated by measuring naive T cells, TRECs, IL-7, and T cell receptor repertoire diversity. Regulatory T cell (Treg) enumeration and function and dendritic cell (DC) enumeration and phenotype were analyzed using flow cytometry. T cell transcriptome analysis was performed on ECP patients after treatment and responders pre- and post-treatment. Four ECP responders demonstrated thymic-dependent T cell recovery, and superior median naïve T cell numbers at 8 and 12 months post-HSCT compared to the aGVHD corticosteroid group. Increased Tregs and Treg suppressive function, reduced cDC/pDC and DC co-stimulatory marker expression in ECP responders suggest upregulated peripheral tolerance; these findings were not observed in partial responders. Responder post-ECP CD3+ T cell transcriptional profile demonstrated 3333 downregulated and 364 upregulated genes, with significant downregulation of ERRα and GαS pathways, and reduced expression of pro-inflammatory and adhesion proteins.

Thymic function improves with successful ECP treatment. ECP reduces T cell activation and impacts peripheral tolerance via DCs and Tregs. Differences in thymic recovery, DC, and Treg cellular patterns and the T cell transcriptome were observed between ECP responders and partial responders and require further validation and investigation in additional patients.

Randomized phase II trial of extracorporeal phototherapy and steroids vs. steroids alone for newly diagnosed acute GVHD

Steroids remain the initial therapy for acute graft-vs.-host disease (AGVHD). Strategies to improve response and minimize steroid exposure are needed. We report results of a randomized, adaptive, Bayesian-designed, phase II trial of prednisone with or without extracorporeal photopheresis (ECP) as an initial therapy for patients with newly diagnosed AGVHD. The primary endpoint was success at day 56 defined as: alive, in remission, achieving AGVHD response without additional therapy, and on <1 mg/kg at day 28 and <0.5 mg/kg on day 56 of steroids. Eighty-one patients were randomized to the ECP arm (n = 51) or steroids alone (n = 30). Median age was 54 years (range: 17-75); 90% had grade II AGVHD and 10% had grades III and IV AGVHD, with skin (85%), upper (22%)/lower (22%) gastrointestinal, and liver (10%) involvement. The ECP arm had a higher probability of success (0.815) and exceeded the predefined threshold for determining the investigational arm promising. ECP was potentially more beneficial than steroids-alone in skin-only AGVHD (response rate: 72% vs. 57%, respectively) than for visceral-organ AGVHD (47% vs. 43%, respectively). The addition of ECP to steroids may result in higher GVHD response as initial therapy for AGVHD, especially for patients with skin-only involvement.

Exofucosylation of Adipose Mesenchymal Stromal Cells Alters Their Secretome Profile

Mesenchymal stromal cells (MSCs) constitute the cell type more frequently used in many regenerative medicine approaches due to their exclusive immunomodulatory properties, and they have been reported to mediate profound immunomodulatory effects in vivo. Nevertheless, MSCs do not express essential adhesion molecules actively involved in cell migration, a phenotypic feature that hampers their ability to home inflamed tissues following intravenous administration. In this study, we investigated whether modification by fucosylation of murine AdMSCs (mAdMSCs) creates Hematopoietic Cell E-/L-selectin Ligand, the E-selectin-binding CD44 glycoform. This cell surface glycan modification of CD44 has previously shown in preclinical studies to favor trafficking of mAdMSCs to inflamed or injured peripheral tissues. We analyzed the impact that exofucosylation could have in other innate phenotypic and functional properties of MSCs. Compared to unmodified counterparts, fucosylated mAdMSCs demonstrated higher in vitro migration, an altered secretome pattern, including increased expression and secretion of anti-inflammatory molecules, and a higher capacity to inhibit mitogen-stimulated splenocyte proliferation under standard culture conditions. Together, these findings indicate that exofucosylation could represent a suitable cell engineering strategy, not only to facilitate the in vivo MSC colonization of damaged tissues after systemic administration, but also to convert MSCs in a more potent immunomodulatory/anti-inflammatory cell therapy-based product for the treatment of a variety of autoimmune, inflammatory, and degenerative diseases.

Ruxolitinib-ECP combination treatment for refractory severe chronic graft-versus-host disease

Glucocorticoid-refractory (SR) chronic (c) graft-versus-host disease (GVHD) is a multisystem immunological disease and the leading cause of non-relapse mortality (NRM) in patients surviving longer than 2 years after allogeneic hematopoietic cell transplantation. Both ruxolitinib (RUX) and extracorporeal photopheresis (ECP) have shown activity for SR-cGVHD which motivated us to treat refractory cGHVD patients with the RUX-ECP combination. In this retrospective survey, 23 patients received RUX-ECP as salvage therapy for SR-cGVHD. The best response (CR or PR) at any time point during treatment was 74% (17/23) including 9% (2/23) CR and 65% (15/23) PR. The 24-months-survival was 75% (CI 56.0-94.1). Newly diagnosed cytopenia occurred in 22% (5/23) and CMV reactivation was observed in 26% (6/23) of the patients. Serum levels of soluble interleukin-2 receptor (sIL-2R) correlated with response. Our retrospective analysis shows that the RUX-ECP combination is safe and has activity in a fraction of patients with SR-cGVHD, which needs validation in a prospective trial.

CD11c+ dendritic cells mediate antigen-specific suppression in extracorporeal photopheresis

Extracorporeal photopheresis (ECP) represents one of the most widespread and effective cell therapies for graft‐versus‐host disease and other T cell‐mediated disorders. However, the key factors affecting the therapeutic efficacy of ECP remain unclear. We hypothesized that therapeutic effects are mediated by ECP‐treated antigen‐presenting dendritic cells (DC). To test this hypothesis, we used the experimental model of contact hypersensitivity (CHS). The ECP’s therapeutic activity improved when the total cell dose of the ECP‐treated cells was increased. We used different haptens during sensitization to demonstrate that the anti‐inflammatory activity of ECP is antigen‐specific. This confirmed the hypothesis that professional antigen‐presenting cells are involved in the mode of action. Also, the ECP’s therapeutic activity was abrogated by the depletion of CD11c⁺ DC, which represents fewer than 1% of all the ECP‐exposed cells. Finally, we confirm the critical importance of CD11c⁺ DC for ECP activity by showing that only a few purified CD11c⁺ DC are sufficient to mediate its therapeutic effect. The finding that ECP‐treated, physiological antigen‐presenting DC alone mediate antigen‐specific modulation of a pathological immune response may result in better‐targeted interventions when treating patients.

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.

Therapeutic implications of extracorporeal photopheresis for rheumatic diseases

Extracorporeal photopheresis (ECP) procedure is based on mononuclear cells (MNC) apheresis and their extracorporeal UVA exposure. It has been applied mainly in hematology and transplantation. Over thirty years of experience confirmed its effectiveness, outstanding safety profile and good tolerance. These observations encourage the implementation of ECP in the treatment of autoimmune connective tissue diseases. The procedure might be considered in refractory cases, when the first line treatment strategies do not control disease activity or immunosuppressants are contraindicated and in the group of patients with high risk of infections. Current literature about using ECP in rheumatology is scarce and most data come from case reports and small observational studies. Systemic sclerosis is the most studied rheumatic disease in the field of ECP use. The disease appeared on the list of clinical applications of ECP therapy according to American Society for Apheresis. However, no European or American guidelines, or recommendations for the treatment in rheumatology suggest ECP as the treatment option. There are no standards in performing ECP in rheumatic diseases concerning indications, length of therapy, concomitant immunosuppressive treatment, follow up or patients characteristic. In this review, we have searched literature concerning ECP use in rheumatic diseases.

Efficacy and immunologic effects of extracorporeal photopheresis plus interleukin-2 in chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD) affects >50% of hematopoietic stem cell transplant patients. Extracorporeal photopheresis (ECP), an immunomodulatory therapy, provides clinical benefit in steroid-refractory (SR) cGVHD, possibly via regulatory T (T_reg) and natural killer (NK) cell expansion. We demonstrated that low-dose interleukin-2 (IL2) led to clinical improvement in SR-cGVHD and stimulated preferential T_reg and NK-cell expansion with minimal effect on conventional T (T_con) cells. We evaluated the effect of ECP (weeks 1-16) plus IL2 (1 × 10⁶ IU/m², weeks 9-16) in 25 adult patients with SR-cGVHD in a prospective phase 2 trial. Objective responses occurred in 29% and 62% of evaluable patients at weeks 8 (ECP alone) and 16 (ECP plus IL2), respectively. Eight weeks of ECP alone was associated with a marked decline in CD4⁺ T_con (P = .03) and CD8⁺ T cells (P = .0002), with minimal change in T_reg cells, T_reg:T_con cell ratio, or NK cells. Adding IL2 induced an increase in T_reg cells (P < .05 at weeks 9-16 vs week 8), T_reg:T_con cell ratio (P < .0001 at weeks 9-16 vs week 8), and NK cells (P < .05 at weeks 9-16 vs week 8). Patients responding to ECP alone had significantly fewer CD4⁺ T_con and CD8⁺ T cells at baseline compared with patients who responded after IL2 addition and patients who did not respond; neither T_reg nor NK cells were associated with response to ECP alone. Altogether, ECP plus IL2 is safe and effective in patients with SR-cGVHD. ECP and IL2 have distinct immunologic effects, suggesting different therapeutic mechanisms of action. This trial was registered at www.clinicaltrials.gov as #NCT02340676.

Extracorporeal Photopheresis: A Case of Immunotherapy Ahead of Its Time

Extracorporeal photopheresis (ECP) is a cell-based immunotherapy that involves the reinfusion of autologous leukocytes after exposure to psoralen and UVA. The treatment has been used for over 30 years, at first on patients with cutaneous T-cell lymphoma (CTCL) and later for the management of patients with graft-versus-host disease (GvHD), sclerosing disorders, atopic dermatitis, and other diseases that may share the common driving factor of a pathogenic T-cell clone or clones in blood circulation. Patients with clinical improvement mount an antigen-specific immune response that may have tolerance traits in the case of GvHD or anticlonal cytotoxic characteristics in the case of CTCL. The exact mechanisms that dictate one response or the other are not fully understood, but the evidence accumulated so far indicates that multiple events occur simultaneously and consequentially contribute to the end result. These include contact of cells with the outside (plastics and tubing of the ECP apparatus), exposure to psoralen and UVA that activates platelets, monocytes, and other myeloid cells, the release of damage-associated molecular patterns, differentiation of monocytes into dendritic cells, and generation and successive presentation of numerous antigens after the phagocytosis of apoptotic cells. Once reintroduced, the ECP product increases the frequency and activity of regulatory T cells (Tregs), shifts the systemic cytokine balance, and promotes extravasation of immune cells that together shape the effects of this treatment. In this review, we summarize the seminal work and most recent literature of the therapeutic mechanisms and reflect on future avenues of improvements and applications of ECP.

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 as first-line strategy in the treatment of acute graft-versus-host disease after hematopoietic stem cell transplantation: A single-center experience

BACKGROUND AIMS

Corticosteroids are the standard first-line treatment for acute graft-versus-host disease (aGVHD), but they are associated with many complications, and less than half of patients have a sustained response.

METHODS

To improve outcomes, we performed a retrospective study to analyze the efficacy of the addition of extracorporeal photopheresis (ECP) to low-dose corticosteroids in 37 adult patients (median age, 57 years) with skin-predominant aGVHD (grade I, n = 17; grade II, n = 18; and grade III, n = 2). All patients received ECP in combination with 1 mg/kg prednisone (n = 26) or topical steroids (n = 11).

RESULTS

Overall response rate was 81% after a median of three ECP procedures (range, 2-8), including 22 complete responses (CR, 59%) and eight very good partial responses (VGPR, 22%). The 11 patients treated with topical corticosteroids achieved CR. Furthermore, 16 (62%) patients reached prednisone withdrawal at a median of 100 days (range, 42-174 days) after its initiation. Eighteen patients developed chronic GVHD (cGVHD); 11 of them (who were in CR of aGVHD) had a new-onset cGVHD, and seven experienced progressive cGVHD (five non-responding and two VGPR patients). A second-line immunosuppressive treatment was initiated in only five (14%) non-responding patients. With a median follow-up of 31 months (range, 6-57 months) 2-year overall survival and non-relapse mortality were 74% and 11%, respectively.

CONCLUSIONS

Overall, the combination of low-dose corticosteroids and ECP appear to be safe and effective for first-line treatment of skin predominant aGVHD.

CD8+ T cells mediate ultraviolet A-induced immunomodulation in a model of extracorporeal photochemotherapy

Extracorporeal photochemotherapy (ECP) that takes advantage of the immunomodulatory effects of UV light has been extensively used for many years for the treatment of several T cell-mediated diseases, including graft-versus-host disease (GvHD) and systemic scleroderma. Immune mechanisms that lead to the establishment of T cell tolerance in ECP-treated patients remain poorly known. In this study, we have tested the effect of UV/psoralen-treated BM-derived dendritic cells, referred to as ECP-BMDCs on the outcome of an antigen-specific T cell-mediated reaction, that is, contact hypersensitivity (CHS), which is mediated by CD8⁺ effector T cells (CD8⁺ T_eff ). The intravenous (i.v.) injection of antigen-pulsed ECP-BMDCs in recipient C57BL/6 mice induced specific CD8⁺ T cells endowed with immunomodulatory properties (referred to as CD8⁺ T_ECP ), which prevented the priming of CD8⁺ T_eff and the development of CHS, independently of conventional CD4⁺ regulatory T cells. CD8⁺ T_ECP mediated tolerance by inhibiting the migration and functions of skin DC and subsequently the priming of CD8⁺ T_eff . CD8⁺ T_ECP displayed none of the phenotypes of the usual CD8⁺ T regulatory cells described so far. Our results reveal an underestimated participation of CD8⁺ T cells to ECP-induced immunomodulation that could explain the therapeutic effects of ECP in T cell-mediated diseases.

Extracorporeal Photopheresis (ECP) and the Potential of Novel Biomarkers in Optimizing Management of Acute and Chronic Graft vs. Host Disease (GvHD)

As the use of hematopoietic stem cell transplantation (HSCT) has become a more widespread and effective treatment for hematological malignant and non-malignant conditions, the need to minimize the harmful effects of graft- vs.-host disease (GvHD) has become more important in achieving good outcomes. With diagnosis of GvHD reliant on its clinical manifestations, research into biomarkers for the diagnosis, progression, and even for the prediction of disease, is imperative to combating the high levels of morbidity and mortality post-HSCT. Despite the development of novel treatment approaches to GvHD, corticosteroids remain the standard first-line treatment, with immunosuppressant therapies as second-line options. These strategies however have significant limitations and associated complications. Extracorporeal Photopheresis (ECP) has shown to be effective and safe in treating patients with symptomatic GvHD. ECP has been shown to have varied effects on multiple parts of the immune system and does not appear to increase the risk of relapse or infection in the post HSCT setting. Even so, ECP can be logistically more complex to organize and requires patients to be sufficiently stable. This review aims to summarize the potential role of biomarkers to help guide individualized treatment decisions in patients with acute and chronic GvHD. In relation to ECP, robust biomarkers of GvHD will be highly useful in informing patient selection, intensity and duration of the ECP schedule, monitoring of response and other treatment decisions alongside the concurrent administration of other GvHD therapies. Further research is warranted to establish how GvHD biomarkers are best incorporated into ECP treatment pathways with the goal of tailoring ECP to the needs of individual patients and maximizing benefit.

CD71 surface analysis of T cells: a simple alternative for extracorporeal photopheresis quality control

BACKGROUND

Extracorporeal photopheresis (ECP) is a leukapheresis-based cellular therapy that is used with increasing frequency worldwide to treat various T-cell-mediated diseases. Currently, the inhibition of T-cell proliferation after photopheresis is analysed frequently using time-consuming assays including radioactive thymidine assays or carboxyfluorescein succinimidyl ester (CFSE) staining. We investigated whether simple surface T-cell staining using surrogate markers of T-cell proliferation can replace time-consuming measurement of T-cell proliferation in ECP quality control.

STUDY DESIGN AND METHODS

T-cell activation markers were investigated by flow cytometry after ECP. Candidates were validated by direct comparison with the classical CFSE T-cell proliferation inhibition test and apoptosis staining. Finally, surface T-cell staining was performed in patient samples in comparison with classical methods.

RESULTS

CD71 expression exhibited the fastest and most robust upregulation, which was detectable as early as 6-8 h after T-cell stimulation and almost completely abrogated by ECP. In a direct comparison with the CFSE T-cell proliferation assay, suppression of CD71 expression after ECP was almost identical and detectable as early as 16 h after stimulation in peripheral blood mononuclear cells of healthy donors. Furthermore, in direct comparison with classical apoptosis staining, the inhibition delta of CD71 after ECP was significantly higher. Moreover, in patients under T-cell suppressive therapy, T-cell-dependent CFSE and CD71 assays exhibited decreased sensitivity to detect ECP treatment and were inferior in comparison to apoptosis staining.

CONCLUSION

Surface CD71 analysis represents a very simple quality control alternative to detect ECP-mediated T-cell proliferation inhibition in normal PBMC samples devoid of T-cell suppressive drugs.

The promise of CD4+FoxP3+ regulatory T-cell manipulation in vivo: applications for allogeneic hematopoietic stem cell transplantation

CD4⁺FoxP3⁺ regulatory T cells (Tregs) are a non-redundant population critical for the maintenance of self-tolerance. Over the past decade, the use of these cells for therapeutic purposes in transplantation and autoimmune disease has emerged based on their capacity to inhibit immune activation. Basic science discoveries have led to identifying key receptors on Tregs that can regulate their proliferation and function. Notably, the understanding that IL-2 signaling is crucial for Treg homeostasis promoted the hypothesis that in vivo IL-2 treatment could provide a strategy to control the compartment. The use of low-dose IL-2 in vivo was shown to selectively expand Tregs versus other immune cells. Interestingly, a number of other Treg cell surface proteins, including CD28, CD45, IL-33R and TNFRSF members, have been identified which can also induce activation and proliferation of this population. Pre-clinical studies have exploited these observations to prevent and treat mice developing autoimmune diseases and graft-versus-host disease post-allogeneic hematopoietic stem cell transplantation. These findings support the development of translational strategies to expand Tregs in patients. Excitingly, the use of low-dose IL-2 for patients suffering from graft-versus-host disease and autoimmune disease has demonstrated increased Treg levels together with beneficial outcomes. To date, promising pre-clinical and clinical studies have directly targeted Tregs and clearly established the ability to increase their levels and augment their function in vivo. Here we review the evolving field of in vivo Treg manipulation and its application to allogeneic hematopoietic stem cell transplantation.

Chemoirradiated neutrophils and T cells differentially affect immune functions of APCs

Extracorporeal photopheresis (ECP) is known as an immunomodulatory therapy with few side effects, which is mainly used in the treatment of cutaneous T cell lymphoma, graft-versus-host disease, and allograft rejection. During ECP, leukocytes are separated from whole blood by leukapheresis, subsequently chemoirradiated with 8-methoxypsoralen and UVA light, and re-infused into the patient. Although clinically effective, its mode of action has not been fully elucidated. In the present study, we analyzed the interaction of chemoirradiated neutrophils and CD3+ lymphocytes with APC in an in vitro model. We report that chemoirradiated CD3+ T cells induced increased expression of activation markers on dendritic cells (DC), macrophages, and monocytes. Coculture of chemoirradiated CD3+ T cells with these APC also led to significantly increased secretion of TNF-α. Although less pronounced, additional activation of APC took place when APC were stimulated with LPS or IFN-γ. In contrast, chemoirradiated neutrophils did not show activating effects on APC. The presence of chemoirradiated neutrophils during LPS and IFN-γ stimulation of DC rather diminished DC and macrophage activation. In line with these findings DC cocultured with chemoirradiated CD3+ T cells, but not neutrophils, showed significantly increased activation of CD3+ responder lymphocytes in a mixed lymphocyte reaction. With this study, we demonstrate that chemoirradiated leukocytes have differential indirect immunomodulatory effects. Whereas chemoirradiated CD3+ T cells activate APC, chemoirradiated neutrophils suppress activation of APC in the presence of other activating factors, suggesting that the composition of the ECP-treated buffy coat might be of importance for its immunomodulatory effects.

A standardized methodical approach to characterize the influence of key parameters on the in vitro efficacy of extracorporeal photopheresis

Extracorporeal photopheresis (ECP) is an autologous immunomodulatory cell therapy that consists of the ex vivo collection of mononuclear cells (MNCs), which are irradiated with UVA in the presence of the photosensitizing agent 8-methoxypsoralen (8-MOP) to induce cell apoptosis. This photoactivated cell preparation is then reinfused into the patient. While the clinical benefits of ECP are well-demonstrated, no study has yet characterized the influence of variations in the composition of the cell preparation on the efficacy of ECP in vitro. Here, we describe a standardized methodology for the in vitro assessment of ECP that uses the human lymphoma T-cell line and mimics the clinical procedure. By quantifying cell apoptosis, inhibition of cell proliferation, and 8-MOP consumption, we used this approach to characterize the specific influence of key variables on the cellular response to ECP. We found that (i) increases in hematocrit and plasma concentrations attenuated the cellular response to ECP; (ii) plasma concentration was the only variable tested that influenced 8-MOP consumption; and (iii) the loss of efficacy due to variations in the concentration of certain blood components could be counteracted by modulating the UVA dose. This methodology may enable evaluation of other leukapheresis preparation protocols and better determination of the optimal working parameters for ECP.

Extracorporeal Photopheresis for Bronchiolitis Obliterans Syndrome After Lung Transplantation

BACKGROUND

Lung transplantation is a therapeutic option for select patients with end-stage lung disease. However, successful lung transplantation is hampered by chronic lung allograft dysfunction, in particular bronchiolitis obliterans syndrome (BOS). Although there is no approved or standard treatment for BOS, which may have several distinct phenotypes, extracorporeal photopheresis (ECP) has shown promising results in patients who develop BOS refractory to azithromycin treatment.

METHODS

We reviewed all relevant clinical data indexed on PubMed from 1987 to 2017 to evaluate the role of ECP in patients with BOS.

RESULTS

Seven small studies investigated the immunomodulatory effects of ECP in patients after solid organ transplant, and 12 studies reported clinical data specific to ECP therapy for BOS. Studies indicate that ECP triggers an apoptotic cellular cascade that exerts various immunomodulatory effects mediated via increases in anti-inflammatory cytokines, a decrease in proinflammatory cytokines, and an increase in tolerogenic regulatory T cells. Clinical evidence derived from relatively small single-center studies suggests that ECP therapy is associated with improvement or stabilization in lung function and sustainable, statistically significant, decreases in the rate of lung function decline in patients with BOS. Additionally, when adverse event data were reported, ECP was generally well tolerated. None of the comparative studies were randomized.

CONCLUSIONS

Immunomodulation mediated via ECP is a rational therapeutic option that may improve clinical outcomes in patients with BOS, particularly in the context of in-depth patient phenotyping as part of a stratified approach to treatment; good quality randomized controlled trials are needed to confirm observational findings.

An alternative for extracorporeal photopheresis: 8-methoxypsoralen and UVA-treated leucocytes from allogeneic donors improve graft-versus-host disease in mice

BACKGROUND AND OBJECTIVE

Extracorporeal photopheresis (ECP) is an important immune tolerance inducing therapy for graft-versus-host disease (GvHD). However, a sufficient number of ECP cycles cannot be performed in patients with severe GvHD and contraindications for apheresis. Allogeneic sources of leucocytes for use as ECP treatment would be of great benefit. Therefore, this study aimed to test the therapeutic potential of novel sources of leucocytes for ECP.

MATERIALS AND METHODS

Graft-versus-host disease mice were treated with ECP using therapeutic cells from different allogeneic sources. Splenocytes were incubated with 8-methoxypsoralen (8-MOP), irradiated with UVA light and injected into GvHD mice as a model for ECP.

RESULTS

The therapy with 8-MOP/UVA-treated cells from healthy mice of the bone marrow transplantation (BMT) donor strain reduced the GvHD symptoms, at least in a model of chronic GvHD. In the acute GvHD model, 8-MOP/UVA-treated cells from the BMT donor or recipient strain did not show significant improvements in GvHD symptoms or survival time. Pre-activation of cells by mixed lymphocyte reactions before 8-MOP/UVA treatment also failed to result in significant differences in survival time or GvHD score. In contrast, ECP with third-party 8-MOP/UVA-treated cells from a HLA-mismatched donor resulted in a mean survival time of 37 days compared to 21 days in the control group.

CONCLUSION

In our analysis of novel allogeneic leucocyte sources for ECP, we could demonstrate that the source of the 8-MOP/UVA-treated cells is crucial. The underlying immunologic effect of allogeneic 8-MOP/UVA-treated cells needs to be investigated in future studies.

Mini photopheresis for refractory chronic graft-versus-host disease in children and adolescents

BACKGROUND

Extracorporeal photopheresis (ECP) has been established to treat graft-versus-host disease. Our mini ECP technique (mini-ECP) allows for treatment of patients with GVHD and contraindications for classical ECP or low body weight. The safety and efficacy of applying ECP for the long-term treatment of chronic GVHD (cGVHD) have not been described.

STUDY DESIGN AND METHODS

A retrospective analysis of mini-ECP treatments for children and adolescents with cGVHD was performed. Mini-ECP with 100 to 200 mL of whole blood was used to treat 14 patients. The median age at the start of treatment was 7 years (range, 1-17 years), and median body weight was 20 kg (range, 8-53 kg). A total of 703 mini-ECP treatments was performed. The median number of treatments per patient was 35 (range, 8-129), and median treatment duration was 11 months (range, 1.4-28.5 months).

RESULTS

Mini-ECP was well tolerated. Four adverse events occurred in three patients, and two of them were related to the ECP procedure. Complete or partial responses were observed in 10 patients. Steroids were discontinued in seven patients and tapered in three others. Responses were seen in the skin, mouth, gastrointestinal tract, and eyes.

CONCLUSION

Mini-ECP represents a less invasive ECP alternative for low-body-weight patients with cGVHD and contraindications for apheresis.

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.

A phase II/III randomized, multicenter trial of prednisone/sirolimus versus prednisone/ sirolimus/calcineurin inhibitor for the treatment of chronic graft-versus-host disease: BMT CTN 0801

Initial therapy of chronic graft-versus-host disease is prednisone ± a calcineurin-inhibitor, but most patients respond inadequately. In a randomized, adaptive, phase II/III, multicenter trial we studied whether prednisone/sirolimus or prednisone/sirolimus/photopheresis was more effective than prednisone/sirolimus/calcineurin-inhibitor for treating chronic graft-versus-host disease in treatment-naïve or early inadequate responders. Primary endpoints of this study were proportions of subjects alive without relapse or secondary therapy with 6-month complete or partial response in phase II, or with 2-year complete response in phase III. The prednisone/sirolimus/photopheresis arm closed prematurely because of slow accrual and the remaining two-drug versus three-drug study ended in phase II due to statistical futility with 138 evaluable subjects. The two-drug and three-drug arms did not differ in rates of 6-month complete or partial response (48.6% versus 50.0%, P=0.87), or 2-year complete response (14.7% versus 15.5%, P=0.90). Serum creatinine values >1.5 times baseline were less frequent in the calcineurin-inhibitor-free arm at 2 months (1.5% versus 11.7%, P=0.025) and 6 months (7.8% versus 24.0%, P=0.016). Higher adjusted Short Form-36 Physical Component Summary and Physical Functioning scores were seen in the two-drug arm at both 2 months (P=0.02 and P=0.04, respectively) and 6 months (P=0.007 and P=0.001, respectively). Failure-free survival and overall survival rates at 2 years were similar for patients in the the two-drug and three-drug arms (48.6% versus 46.2%, P=0.78; 81.5% versus 74%, P=0.28). Based on similar long-term outcomes, prednisone/sirolimus is a therapeutic alternative to prednisone/sirolimus/calcineurin-inhibitor for chronic graft-versus-host disease, being easier to administer and better tolerated. Clinicaltrials.gov identifier: NCT01106833.

Efficacy of Extracorporeal Photopheresis in Patients With Bronchiolitis Obliterans Syndrome After Lung Transplantation

BACKGROUND

Lung transplantation (LT) is only therapeutic option for patients affected by chronic respiratory failure. Chronic rejection, also known as bronchiolitis obliterans syndrome (BOS), is still the main cause of death and the most important factor that influences post-transplantation quality of life. Currently available therapies have not been proven to result in significant benefit in the prevention or treatment of BOS. Extracorporeal photopheresis (ECP) seems to reduce the rate of lung function decline in transplant recipients with progressive BOS.

METHODS

From 1991 until now, 239 LTs were performed at our center. Fifty-four patients (22.5%) developed BOS; 15 of these (27.7%) were treated with ECP. At the beginning of the treatment, all patients showed a mean decline of forced expiratory volume in 1 second (FEV₁) from baseline values of 45.8% ± 17.2%; 2 patients were in long-term oxygen therapy.

RESULTS

Mean follow-up from November 2013 to June 2016 was 11.6 ± 7 months. Twelve patients (80%) showed lung function stabilization with an FEV₁ range after treatment between -6% to +8% from the pre-treatment values. We did not report any adverse effects or increase of infections incidence.

DISCUSSION

ECP seems to be an effective and well-tolerated therapeutic option for LT patients with BOS in terms of stabilization of lung function and increased survival.

A Critical Appraisal of Extracorporeal Photopheresis as a Treatment Modality for Acute and Chronic Graft-Versus-Host Disease

Although significant advances have been made in the biologic understanding of graft-versus-host disease (GVHD) and its treatment options, GVHD remains the single most challenging obstacle to the success of allogeneic hematopoietic cell transplantation (HCT) due to high risk of disabling morbidity and mortality. Extracorporeal photopheresis (ECP) has promising effects in controlling steroid-refractory GVHD, both acute and chronic, and it has been studied extensively. Its putative immunomodulatory mechanisms, while not immunosuppressive, position ECP as an attractive treatment strategy for GVHD patients who are already receiving global immunosuppression. However, ECP is relatively underutilized due in part to limited access and time commitment. Here, we review the recent findings on the ECP efficacy in both acute and chronic GVHD, primarily for steroid-refractory status, and we critically appraise its benefits. We also explore salient considerations on the optimal use of ECP in the treatment of refractory GVHD.

Sirolimus Increases T-Cell Abundance in the Sun Exposed Skin of Kidney Transplant Recipients

BACKGROUND

Kidney transplant recipients (KTRs) receiving the mammalian target of rapamycin inhibitor sirolimus may display a reduced risk of skin cancer development compared to KTRs receiving calcineurin inhibitors. Despite studies investigating the effects of these 2 drug classes on T cells in patient blood, the effect these drugs may have in patient skin is not yet known.

METHODS

Fifteen patients with chronic kidney disease (not recipients of immunosuppressive drugs), and 30 KTRs (15 receiving a calcineurin inhibitor, and 15 receiving sirolimus) provided matched samples of blood, sun exposed (SE) and non-SE skin. The abundance of total CD8⁺ and CD4⁺ T cells, memory CD8⁺ and CD4⁺ T cells, and regulatory T (Treg) cells in each sample was then assessed by flow cytometry.

RESULTS

Sirolimus treatment significantly increased absolute numbers of CD4⁺ T cells, memory CD8⁺- and CD4⁺ T cells, and Treg cells in SE skin versus paired samples of non-SE skin. No differences were found in the absolute number of any T cell subset in the blood. Correlation analysis revealed that the percentage of T cell subsets in the blood does not always accurately reflect the percentage of T-cell subsets in the skin of KTRs. Furthermore, sirolimus significantly disrupts the balance of memory CD4⁺ T cells in the skin after chronic sun exposure.

CONCLUSIONS

This study demonstrated that immunosuppressive drug class and sun exposure modify the abundance of multiple T-cell subsets in the skin of KTRs. Correlation analysis revealed that the prevalence of Treg cells in KTR blood does not accurately reflect the prevalence of Treg cells in KTR skin.

In vitro effects of different 8-methoxypsoralen treatment protocols for extracorporeal photopheresis on mononuclear cells

Extracorporeal photopheresis (ECP) is an important second-line therapy for graft-versus-host disease. A central therapeutic mechanism is the induction of immune tolerance through apoptosis in patient’s leukocytes, caused by ex vivo incubation with 8-methoxypsoralen (8-MOP) and subsequent UVA irradiation.

We hypothesized that different 8-MOP incubation times and an additional 8-MOP removal step could influence the apoptosis kinetics of leukocytes in general and in particular could lead to different apoptotic levels in the leukocyte subpopulations. After 8-MOP/UVA treatment of human leukocytes, cells were cultured and the percentage of annexin V positive cells from several leukocyte subpopulations was determined. Only regulatory T cells (Tregs) were relatively resistant to 8-MOP/UVA induced apoptosis. When cells were incubated for 30 minutes with 8-MOP prior to UVA exposure, higher percentages of annexin V positive cells were detected on day 1 and day 2 after treatment. Removal of 8-MOP after UVA exposure caused no significant changes in the apoptosis kinetics during the 72 h culture period compared with unwashed cells. The results of our in vitro study indicate that it could be possible to adjust the apoptosis kinetics via modulation of the 8-MOP incubation time. In further in vivo studies it should be elucidated to which extent different apoptosis kinetics influence the therapeutic effect of ECP since steady-state apoptosis levels are probably important for establishing a long lasting immune tolerance. Furthermore we found that Tregs, according to their well-known tolerogenic function, are more resistant to apoptosis after 8-MOP/UVA treatment compared to GvHD inducing T cell populations.

The inflammatory role of phagocyte apoptotic pathways in rheumatic diseases

Rheumatoid arthritis affects nearly 1% of the world's population and is a debilitating autoimmune condition that can result in joint destruction. During the past decade, inflammatory functions have been described for signalling molecules classically involved in apoptotic and non-apoptotic death pathways, including, but not limited to, Toll-like receptor signalling, inflammasome activation, cytokine production, macrophage polarization and antigen citrullination. In light of these remarkable advances in the understanding of inflammatory mechanisms of the death machinery, this Review provides a snapshot of the available evidence implicating death pathways, especially within the phagocyte populations of the innate immune system, in the perpetuation of rheumatoid arthritis and other rheumatic diseases. Elevated levels of signalling mediators of both extrinsic and intrinsic apoptosis, as well as the autophagy, are observed in the joints of patients with rheumatoid arthritis. Furthermore, risk polymorphisms are present in signalling molecules of the extrinsic apoptotic and autophagy death pathways. Although research into the mechanisms underlying these pathways has made considerable progress, this Review highlights areas where further investigation is particularly needed. This exploration is critical, as new discoveries in this field could lead to the development of novel therapies for rheumatoid arthritis and other rheumatic diseases.

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.

Regulatory T Cells in Chronic Graft-Versus-Host Disease After Extracorporeal Photopheresis: Correlation With Skin and Global Organ Responses, and Ability to Taper Steroids

BACKGROUND

Induction of immune tolerance by an increase in regulatory T (Treg) cells after extracorporeal photopheresis (ECP) is thought to contribute to how ECP exerts its therapeutic effect in patients with chronic graft-versus-host disease (cGvHD). We investigated whether percentages and absolute counts of Treg cells changed post-ECP, and examined correlation with response.

METHODS

Absolute counts and % of CD4+ T cells and Treg cells (CD4 + CD25 + FOXP3 + CD127dim/-) were evaluated using flow cytometry in 32 patients with cGvHD treated by ECP for a minimum of 3 months, and up to 12 months. CD4+ or Treg cells at baseline to 12 months post-ECP were compared with changes in skin disease scores or global organ involvement, or the ability to taper steroids, at 14, 28, and 56 weeks.

RESULTS

Regulatory T cells % increased significantly above any overall changes in CD4+ % at 6, 9, and 12 months post-ECP. There was no statistically significant association between Treg cells and skin or steroid response, whereas a larger increase in CD4+ count from baseline to 1 to 3 months corresponded to increased odds of being able to reduce steroid dose by 50% or greater at 14 weeks. Skin and global organ responders at 28 weeks had higher median Treg cell counts 3 months post-ECP than nonresponders, as did steroid responders at 56 weeks who were 12 months post-ECP.

CONCLUSIONS

Regulatory T cell counts and % varied greatly among cGvHD patients, and the increase post-ECP was not significant until 6 months. No clear correlation was found between Treg cells and clinical improvement, suggesting that increases in Treg cell numbers and/or proportions are not driving the mechanism leading to a response after ECP.