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

Boost of innate immunity cytokines as biomarkers of response to extracorporeal photopheresis in patients with leukaemic cutaneous T-cell lymphoma

BACKGROUND

Extracorporeal photopheresis (ECP) has emerged as a systemic first-line immunomodulatory therapy in leukaemic cutaneous T-cell lymphoma (L-CTCL) and is now beginning to be utilized in other T-cell-mediated diseases. Although ECP has been used for nearly 30 years, its mechanisms of action are not sufficiently understood, and biomarkers for response are scarce.

OBJECTIVES

We aimed to investigate the immunomodulatory effects of ECP on cytokine secretion patterns in patients with L-CTCL, to help elucidate its mechanism of action.

METHODS

A total of 25 patients with L-CTCL and 15 healthy donors (HDs) were enrolled in this retrospective cohort study. Concentrations of 22 cytokines were simultaneously quantified by using multiplex bead-based immunoassays. Neoplastic cells in patients' blood were evaluated by flow cytometry.

RESULTS

Firstly, we observed a distinct cytokine profile pattern difference between L-CTCLs and HDs. There was a significant loss of tumour necrosis factor (TNF)-α, and significant increase of interleukins (IL)-9, IL-12 and IL-13 in the sera of patients with L-CTCL compared with HDs. Secondly, patients with L-CTCL who received ECP were classified as treatment responders and nonresponders according to the quantitative reduction of malignant burden in their blood. We evaluated cytokine levels in culture supernatants from patients' peripheral blood mononuclear cells (PBMCs) at baseline and 27 weeks after ECP initiation. Strikingly, PBMCs purified from ECP responders released statistically higher concentrations of innate immune cytokines IL-1α, IL-1β, granulocyte-macrophage colony-stimulating factor (GM-CSF) and TNF-α in comparison with ECP nonresponders. In parallel, responders showed clearance of erythema, reduction of malignant clonal T cells in the blood, and a potent boost of relevant innate immune cytokines in individual patients with L-CTCL.

CONCLUSIONS

Taken together, our results demonstrate that ECP stimulates the innate immune network, and facilitates redirection of the tumour-biased immunosuppressive microenvironment towards proactive antitumour immune responses. The alterations of IL-1α, IL-1β, GM-CSF and TNF-α can be used as biomarkers of response to ECP in patients with L-CTCL.

Effects of Ramadan Fasting on Extracorporeal Photopheresis Outcomes

Although there are many studies on the impact of Ramadan fasting on health in the medical literature, the effects have not been explored in Muslim patients undergoing extracorporeal photopheresis (ECP). This report aimed to describe the potential effects of Ramadan fasting on ECP treatment outcomes. Patients undergoing ECP were prospectively evaluated before and during the month of Ramadan 1443 AH (2022 AD) at the Abu Dhabi Stem Cells Center (ADSCC), United Arab Emirates. The following ECP outcomes were assessed: treatment completion, adverse events reported, body mass index (BMI), and laboratory test results, including complete blood count (CBC), C-reactive protein (CRP), and other systemic immune-inflammatory biomarkers (SIIBs). No statistically significant differences were found in most of the variables analyzed in the three patients who underwent ECP before and during the holy month. Two non-fasting patients were not able to complete the Ramadan ECP schedule, and one fasting patient experienced a vascular access event during his first procedure in Ramadan. These findings suggest that fasting during Ramadan could add further risk factors and develop serious complications related to the ECP treatment. Therefore, we suggest that fasting should be avoided during photopheresis treatment, and we provided recommendations to achieve the best possible clinical outcomes.

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.

Recent advances in graft-versus-host disease

Acute and chronic graft-versus-host disease (GVHD) continue to present a significant challenge to physicians, accounting for considerable haematopoietic stem cell transplant (HSCT)-related morbidity and mortality, particularly those patients with steroid-refractory disease. In this review, we discuss recent advances in understanding the underlying pathophysiology, prevention and management of acute and chronic GVHD. Barriers to progress include the difficulty in obtaining high-quality evidence with sufficient patient numbers to identify optimal preventative and treatment strategies, with the heterogeneity of multiple patient, donor, graft and transplant-related factors, in addition to limited availability of human tissue to study the underlying pathophysiology, particularly in steroid-refractory disease. Continued collaborative efforts to improve our understanding of the pathophysiology involved, particularly in steroid-refractory disease, identification of biomarkers to permit risk stratification, and further well-designed randomised clinical trials are essential to help physicians determine optimal GVHD preventative and treatment strategies for each individual patient.

Refractory pemphigus vulgaris and high-intensity extracorporeal photopheresis: A case report

A 41-year-old man with oral pemphigus vulgaris (PV) presented to our clinic with a history of no response to numerous immunosuppressant agents and was referred for extracorporeal photopheresis (ECP) therapy. Although the patient underwent a high-intensity ECP regimen for five months, which included two different photopheresis systems, his oral dysesthesia continued to interfere with oral intake, leading to continued weight loss and other adverse events. The intervention was associated with changes in several immune cell subpopulations without modifying the anti-epidermal antibody titers, aligned with his poor clinical outcome. To the best of the authors' knowledge, this is the first report to examine immunophenotyping of a PV patient who was refractory to previous immunosuppression and recalcitrant to high-intensity 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.

Current Prophylaxis and Treatment Approaches for Acute Graft-Versus-Host Disease in Haematopoietic Stem Cell Transplantation for Children With Acute Lymphoblastic Leukaemia

Acute graft-versus-host disease (aGvHD) continues to be a leading cause of morbidity and mortality following allogeneic haematopoietic stem cell transplantation (HSCT). However, higher event-free survival (EFS) was observed in patients with acute lymphoblastic leukaemia (ALL) and grade II aGvHD vs. patients with no or grade I GvHD in the randomised, controlled, open-label, international, multicentre Phase III For Omitting Radiation Under Majority age (FORUM) trial. This finding suggests that moderate-severity aGvHD is associated with a graft-versus-leukaemia effect which protects against leukaemia recurrence. In order to optimise the benefits of HSCT for leukaemia patients, reduction of non-relapse mortality-which is predominantly caused by severe GvHD-is of utmost importance. Herein, we review contemporary prophylaxis and treatment options for aGvHD in children with ALL and the key challenges of aGvHD management, focusing on maintaining the graft-versus-leukaemia effect without increasing the severity of GvHD.