Sézary Syndrome and Atopic Dermatitis: Comparison of Immunological Aspects and Targets

Role of IL-4 and IL-13 in Cutaneous T Cell Lymphoma

The interleukins IL-4 and IL-13 are increasingly recognized contributors to the pathogenesis of cutaneous T cell lymphomas (CTCLs), and their role in disease-associated pruritus is accepted. The prevailing Th2 profile in advanced CTCL underscores the significance of understanding IL-4/IL-13 expression dynamics from the early stages of disease, as a shift from Th1 to Th2 may explain CTCL progression. Targeted agents blocking key cytokines of type 2 immunity are established therapeutics in atopic disorders and have a promising therapeutic potential in CTCL, given their involvement in cutaneous symptoms and their contribution to the pathogenesis of disease. IL-4, IL-13, and IL-31 are implicated in pruritus, offering therapeutic targets with dupilumab, tralokinumab, lebrikizumab, and nemolizumab. This review analyzes current knowledge on the IL-4/IL-13 axis in mycosis fungoides and Sezary syndrome, the most common types of CTCL, examining existing literature on the pathogenetic implications with a focus on investigational treatments. Clinical trials and case reports are required to shed light on novel uses of medications in various diseases, and ongoing research into the role of IL-4/IL-13 axis blockers in CTCL therapy might not only improve the management of disease-related pruritus but also provide in-depth insights on the pathophysiologic mechanisms of CTCL.

Dupilumab-Associated Lymphoid Reactions in Patients With Atopic Dermatitis

Importance

Since the increased use of dupilumab for atopic dermatitis (AD) in daily practice, several cases have been reported on the development of cutaneous T-cell lymphomas (CTCL) and lymphoid infiltrates.

Objective

To provide insight in the clinical and histopathologic features of patients with AD clinically suspected for CTCL during dupilumab treatment.

Design, Setting, and Participants

This retrospective observational case series included adult (≥18 years) patients with AD treated with dupilumab between October 2017 and July 2022 at the University Medical Center Utrecht in the Netherlands.

Main outcomes and measures

Relevant patient, disease, and treatment characteristics were evaluated. Skin biopsies before, during, and after treatment were collected and reassessed.

Results

Fourteen patients (54.5% male) with a median (IQR) age of 56 (36-66) years suspected for CTCL with deterioration of symptoms during dupilumab treatment were included. Of 14 patients, 3 were retrospectively diagnosed with preexistent mycosis fungoides (MF). Eleven patients with AD were eventually diagnosed with a lymphoid reaction (LR). These patients showed MF-like symptoms; however, histopathologic findings were different, and included sprinkled distribution of small hyperchromatic lymphocytes in the upper epidermal section, a dysregulated CD4:CD8 ratio, and CD30 overexpression, without loss of CD2/CD3/CD5. The median time to clinical worsening was 4.0 months (IQR, 1.4-10.0). Posttreatment biopsies showed complete clearance of the LR in all patients.

Conclusions and relevance

This study found that dupilumab treatment can cause a reversible and benign LR, which mimics a CTCL, though has distinctive histopathologic features.

Dupilumab-associated mycosis fungoides: a cross-sectional study

Treating atopic dermatitis (AD) with dupilumab, a monoclonal antibody that inhibits interleukin-4 (IL-4) and interleukin-13 (IL-13), may be associated with the progression of mycosis fungoides (MF).This study aims to examine the associations between the length of dupilumab treatment, age and sex, and the onset of MF.An institutional data registry and literature search were used for a retrospective cross-sectional study. Only patients with a diagnosis of MF on dupilumab for the treatment of AD and eczematous dermatitis were included.The primary outcome was the length of dupilumab exposure, age, sex, and the onset of MF. Linear correlations (Pearson) and Cox regression analysis were used to assess the correlation and the risk.A total of 25 patients were included in this study. Five eligible patients were identified at our institution. In addition, a PubMed review identified an additional 20 patients. At the time of MF diagnosis, the median age was 58, with 42% female. Disease history was significant for adult-onset AD in most patients (n = 17, 65.4%) or recent flare of AD previously in remission (n = 3, 11.5%). All patients were diagnosed with MF, and one patient progressed to Sézary syndrome while on dupilumab, with an average duration of 13.5 months of therapy prior to diagnosis. Tumor stage at diagnosis of MF was described in 19 of the cases and ranged from an early-stage disease (IA) to advanced disease (IV). Treatment strategies included narrow-band UVB therapy, topical corticosteroids, brentuximab, pralatrexate, and acitretin. Male gender, advanced-stage disease, and older age correlated significantly with the hazard of MF onset and a shorter time to onset during dupilumab treatment.Our results suggest a correlation between the duration of dupilumab treatment and the diagnosis of MF, the higher MF stage at diagnosis, and the shorter the duration of using dupilumab to MF onset. Furthermore, elderly male patients appeared to be more at risk as both male gender and older age correlated with a hazard of MF diagnosis. The results raise the question as to whether the patients had MF misdiagnosed as AD that was unmasked by dupilumab or if MF truly is an adverse effect of treatment with dupilumab. Close monitoring of these patients and further investigation of the relationship between dupilumab and MF can shed more light on this question .

Mechanism of action of chlormethine gel in mycosis fungoides

Mycosis fungoides (MF), the most common type of cutaneous T-cell lymphoma, is characterized by proliferation of malignant skin-tropic T cells. Progression from early-stage disease (skin patches and/or plaques) to more advanced stages (cutaneous tumours, erythroderma or extracutaneous involvement) occurs slowly and can be discontinuous. Prognosis is poor for the ~25% of patients who progress to advanced disease. Patients at any stage of MF may experience reduced health-related quality of life (QoL) via a spectrum of physically and psychologically debilitating symptoms that can impact many aspects of daily life. Allogeneic stem-cell transplantation is a curative treatment option for some patients with advanced disease, but otherwise there is currently no cure for MF; patients are often refractory to several treatments and require lifelong management. The goals of therapy are symptom control, prevention of disease progression, avoidance of treatment-related toxicity and maintenance/improvement of QoL. Although treatment regimens exist it can be difficult to know how to prioritize them, hence therapies are tailored according to patient needs and drug availabilities, following clinical recommendations. International consensus guidelines recommend skin-directed therapies (SDTs) as first-line treatment for early-stage disease, and SDTs combined with systemic therapy for advanced stages. Chlormethine (CL), also known as mechlorethamine, chlorethazine, mustine, HN2, caryolysine and embichin, is a synthetic deoxyribonucleic acid-alkylating agent that was used as a chemical weapon (mustard gas) during the First World War. Subsequent investigation revealed that survivors of mustard gas exposure had lymphocytopenia, and that CL could inhibit rapidly proliferating malignant T cells. CL has since been developed as a topical treatment for MF and prescribed as such for over 70 years. This review aims to summarize the current knowledge regarding the mechanism of action of CL in the cutaneous micro-environment, in the specific context of MF treatment.

HLA-DR Helps to Differentiate Erythrodermic Cutaneous T-cell Lymphoma from Erythrodermic Inflammatory Dermatoses in Flow Cytometry

Differential diagnosis of erythroderma is challenging in dermatology, especially in differentiating erythrodermic cutaneous T-cell lymphoma from erythrodermic inflammatory dermatoses. This study retrospectively reviewed the peripheral blood flow cytometric results of 73 patients diagnosed with erythroderma at Peking University First Hospital from 2014 to 2019. The flow cytometry antibody panel included white blood cell markers, T-cell markers, B-cell markers, T-cell activation markers, and T helper cell differentiation markers. Features of the cell surface antigens were compared between 34 patients with erythrodermic cutaneous T-cell lymphoma and 39 patients with erythrodermic inflammatory dermatoses. The percentage of HLA-DR+/CD4+T cells was the most pronounced marker to distinguish erythrodermic cutaneous T-cell lymphoma from erythrodermic inflammatory dermatoses, with a threshold of 20.85% (sensitivity 96.77%, specificity 70.37%, p = 0.000, area under the curve (AUC) 0.882), suggesting its potential capability in the differential diagnosis of erythrodermic cutaneous T-cell lymphoma from erythrodermic inflammatory dermatoses. Moreover, in contrast to erythrodermic inflammatory dermatoses, the percentage of Th17 cells was significantly downregulated in erythrodermic cutaneous T-cell lymphoma (p = 0.001), demonstrating a dysregulated immune environment in erythrodermic cutaneous T-cell lymphoma.

Dupilumab-Associated Sezary Syndrome

Dupilumab is a monoclonal antibody that inhibits interleukin-4 (IL-4) and interleukin-13 (IL-13), approved for the treatment of adults with moderate-to-severe atopic dermatitis (AD). While recent reports have described cases of new-onset mycosis fungoides (MF) following treatment with dupilumab for AD, to our knowledge only one patient has been delineated with the progression to SS. We present an additional case of a patient who was diagnosed with SS following treatment with dupilumab for adult-onset AD and asthma. We examine SS as a possible side effect of dupilumab while also discussing management and theories to explain this phenomenon.

Mycosis Fungoides and Sézary Syndrome: Microenvironment and Cancer Progression

Mycosis fungoides and Sézary syndrome are epidermotropic cutaneous lymphomas, and both of them are rare diseases. Mycosis fungoides is the most frequent primary cutaneous lymphoma. In about 25% of patients with mycosis fungoides, the disease may progress to higher stages. The pathogenesis and risk factors of progression in mycosis fungoides and Sézary syndrome are not yet fully understood. Previous works have investigated inter- and intrapatient tumor cell heterogeneity. Here, we overview the role of the tumor microenvironment of mycosis fungoides and Sézary syndrome by describing its key components and functions. Emphasis is put on the role of the microenvironment in promoting tumor growth or antitumor immune response, as well as possible therapeutic targets. We focus on recent advances in the field and point out treatment-related alterations of the microenvironment. Deciphering the tumor microenvironment may help to develop strategies that lead to long-term disease control and cure.

Atopic Dermatitis with Multiple Comorbidities Treated with Dupilumab. A Case Report and Review of the Literature Regarding the Safety of Dupilumab

Dupilumab is the only available biological treatment for moderate-to-severe atopic dermatitis (AD). Even so, limited clinical data regarding its safety profile are available. Interactions with other drugs and the adverse effects of Dupilumab on patients with multiple comorbidities, such as chronic heart disease, diabetes, chronic kidney disease, etc., are not known yet. Moreover, there have been described cases of cutaneous lymphomas induced by Dupilumab. Therefore, the clinician that wants to start treatment for moderate-to-severe atopic dermatitis, which does not respond to conventional drugs, might be reluctant to choose biologic agents such as Dupilumab. In this paper, we reported a case of severe atopic dermatitis with multiple comorbidities in which the patient was successfully treated with Dupilumab despite numerous underlying conditions. We also conducted a review of the current literature on the safety profile of Dupilumab in special categories of patients with comorbidities, such as heart, kidney, and liver disease, oncologic conditions, and during pregnancy.

Genetic alterations and oxidative stress in T cell lymphomas

T cell lymphomas encompass a diverse group of Non-Hodgkin lymphomas with a wide spectrum of clinical, immunological and pathological manifestations. In the last two decades there has been a progress in our understanding of the cell of origin, genetic abnormalities and their impact on behaviour in T cell lymphomas. Genetic alterations are one of the critical drivers of the pathogenesis of T cell lymphoma. Disease progression has been correlated with multiple genetic abnormalities where malignant clones arise primarily out of the host immune surveillance arsenal. There are many cellular processes involved in disease development, and some of them are T cell signaling, differentiation, epigenetic modifications, and immune regulation. Modulation of these crucial pathways via genetic mutations and chromosomal abnormalities possessing either point or copy number mutations helps tumor cells to develop a niche favourable for their growth via metabolic alterations. Several metabolic pathways especially regulation of redox homeostasis is critical in pathogenesis of lymphoma. Disruption of redox potential and induction of oxidative stress renders malignant cells vulnerable to mitochondrial damage and triggers apoptotic pathways causing cell death. Targeting genetic abnormalities and oxidative stress along with current treatment regime have the potential for improved therapeutics and presents new combination approaches towards selective treatment of T cell lymphomas.

Gut dysbiosis in cutaneous T-cell lymphoma is characterized by shifts in relative abundances of specific bacterial taxa and decreased diversity in more advanced disease

BACKGROUND

Cutaneous T-cell lymphoma (CTCL) patients often suffer from recurrent skin infections and profound immune dysregulation in advanced disease. The gut microbiome has been recognized to influence cancers and cutaneous conditions; however, it has not yet been studied in CTCL.

OBJECTIVES

To investigate the gut microbiome in patients with CTCL and in healthy controls.

METHODS

Case-control study conducted between January 2019 and November 2020 at Northwestern's busy multidisciplinary CTCL clinic (Chicago, Illinois, USA) utilizing 16S ribosomal RNA gene amplicon sequencing and bioinformatics analyses to characterize the microbiota present in fecal samples of CTCL patients (n=38) and age-matched healthy controls (n=13) from the same geographical region.

RESULTS

Gut microbial α-diversity trended lower in patients with CTCL and was significantly lower in patients with advanced CTCL relative to controls (p=0.015). No differences in β-diversity were identified. Specific taxa were significantly reduced in patient samples; significance was determined using adjusted p-values (q-values) that accounted for a false discovery rate threshold of 0.05. Significantly reduced taxa in patient samples included the phylum Actinobacteria (q=0.0002), classes Coriobacteriia (q=0.002) and Actinobacteria (q=0.03), order Coriobacteriales (q=0.003), and genus Anaerotruncus (q=0.01). The families of Eggerthellaceae (q=0.0007) and Lactobacillaceae (q=0.02) were significantly reduced in patients with high skin disease burden.

CONCLUSIONS

Gut dysbiosis can be seen in patients with CTCL compared to healthy controls and is pronounced in more advanced CTCL. The taxonomic shifts associated with CTCL are similar to those previously reported in atopic dermatitis and opposite those of psoriasis, suggesting microbial parallels to the immune profile and skin barrier differences between these conditions. These findings may suggest new microbial disease biomarkers and reveal a new angle for intervention.

Safety and Danger Considerations of Novel Treatments for Atopic Dermatitis in Context of Primary Cutaneous Lymphomas

The impact of new and emerging therapies on the microenvironment of primary cutaneous lymphomas (PCLs) has been recently raised in the literature. Concomitantly, novel treatments are already used or registered (dupilumab, upadacitinib) and others seem to be added to the armamentarium against atopic dermatitis. Our aim was to review the literature on interleukins 4, 13, 22, and 31, and JAK/STAT pathways in PCLs to elucidate the safety of using biologics (dupilumab, tralokinumab, fezakinumab, nemolizumab) and small molecule inhibitors (upadacitinib, baricitinib, abrocitinib, ruxolitinib, tofacitinib) in the treatment of atopic dermatitis. We summarized the current state of knowledge on this topic based on the search of the PubMed database and related references published before 21 October 2021. Our analysis suggests that some of the mentioned agents (dupilumab, ruxolitinib) and others may have a direct impact on the progression of cutaneous lymphomas. This issue requires further study and meticulous monitoring of patients receiving these drugs to ensure their safety, especially in light of the FDA warning on tofacitinib. In conclusion, in the case of the rapid progression of atopic dermatitis/eczema, especially in patients older than 40 years old, there is a necessity to perform a biopsy followed by a very careful pathological examination.

Evolution of Dupilumab-Associated Cutaneous Atypical Lymphoid Infiltrates

BACKGROUND

Observations highlighting the "unmasking" of cutaneous T-cell lymphoma after treatment with dupilumab for atopic dermatitis (AD) have been recently reported. However, there remains a paucity of literature describing the evolution of clinical and histopathological features that characterizes this phenomenon.

OBJECTIVE

To define the clinical and histopathologic evolution of atypical lymphoid infiltrates after the administration of dupilumab for AD.

METHODS

A cross-sectional study of clinical and histopathologic features in 7 consecutive patients with a diagnosis of "atypical lymphoid infiltrate" or mycosis fungoides (MF) on dupilumab for AD was performed.

RESULTS

Seven patients with atypical lymphoid infiltrates or MF in evolution after dupilumab therapy (age range 27-74 years) were reviewed. Average duration of AD before MF diagnosis was 5.7 years, and the average duration on dupilumab treatment was 9.8 months. Notable histopathologic features across predupilumab and postdupilumab biopsies included progressive increase in the densities of the atypical lymphoid infiltrates (7/7), presence of atypical epidermotropic lymphocytes (6/7), and papillary dermal fibrosis (6/7).

LIMITATIONS

Small retrospective cohort study.

CONCLUSION

These cases highlight the transformation of lymphoid infiltrates after dupilumab treatment for AD and emphasize the importance of clinical and histopathologic evaluation before and during treatment with dupilumab for treatment-refractory presumed AD.

Mycosis fungoides and Sézary syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are primary cutaneous T-cell lymphomas (CTCL) with not yet fully understood etiology and pathogenesis. Conceptually, MF and SS are classified as distinct entities arising from different T helper cell subsets. MF is the most common CTCL entity, while SS is very rare. MF presents clinically with patch, plaque and/or tumor stages, but can also evolve as erythroderma, which in turn is pathognomonic for SS. SS is characterized by a detectable tumor-cell burden (Sézary cells) in the peripheral blood consistent with advanced-stage disease and a poor prognosis. In early-stage disease of MF, which is the predominant form, the prognosis is generally favorable. However, in up to 30 % of patients, there is progression of skin lesions, which can ultimately lead to visceral involvement. The histological manifestation of MF can be subtle in early-stage disease and therefore a careful clinicopathological correlation is paramount. The treatment of MF/SS is dependent on the disease stage. Therapeutic options include both skin-directed and systemic regimens. Apart from allogeneic stem cell transplantation (alloSCT), there is as yet no curative therapy for MF/SS. Accordingly, the treatment approach is symptom oriented and aims to reduce the tumor burden and improve health-related quality of life. However, the therapeutic landscape for CTCL is constantly being expanded by the discovery of novel therapeutic targets.

Großzellig-anaplastisches T-Zell-Lymphom und Mycosis fungoides unter der Therapie mit Dupilumab

Dupilumab ist das erste zielgerichtete Biologikum, das bei mittelschwerer bis schwerer atopischer Dermatitis angewendet werden kann. Der monoklonale Antikörper hemmt die Interleukin-4- und Interleukin-13-Signalübertragung 1. Dupilumab belegt für die Behandlung von atopischen und allergischen Erkrankungen ein gutes Verträglichkeitsprofil. Gleichwohl sollten Ärzte seine Neuheit und das Potenzial für unerwartete und unerwünschte Arzneimittelwirkungen berücksichtigen. Wir stellen einen Patienten vor, der nach Einleitung von Dupilumab ein großzellig-anaplastisches T-Zell-Lymphom mit Befall des supraklavikulären Lymphknotens und eine Mycosis fungoides entwickelte.

Safety of dupilumab in patients with atopic dermatitis: expert opinion

Introduction: Dupilumab, the first biologic drug to be approved for the treatment of moderate to severe atopic dermatitis in adolescents and adults, has shown efficacy and safety in clinical trials. Data on long-term safety is limited but crucial for pharmacovigilance. Therefore, we performed this review to evaluate available real-world data on the long-term safety of dupilumab in atopic dermatitis.Areas covered: PubMed and Google Scholar databases were searched for randomized controlled clinical trials (RCTs), observational studies, case series, and case reports regarding the use of dupilumab for the treatment of atopic dermatitis. Adverse events were summarized and critically evaluated.Expert opinion: Atopic dermatitis patients receiving dupilumab reported ocular surface disease more often than patients receiving placebo. Real-world data show previously unreported adverse events (blood eosinophilia, rosacea-like skin lesions, weight gain), but their mechanistic association to dupilumab treatment still requires clarification. Cutaneous T-cell lymphomas occurring under the therapy with dupilumab might be unrelated to the drug use itself but long-term follow-up data of large patient cohorts is necessary to rule out such possibility. Real-world data show that dupilumab is well tolerated in atopic dermatitis; however, ocular adverse events are not rare. Registries are needed to monitor future adverse events.

Nomenclature and clinical phenotypes of atopic dermatitis

Atopic dermatitis is a heterogeneous disease and resists classification. In this review, we discuss atopic dermatitis nomenclature and identify morphologic phenotypes, which will facilitate correct diagnoses and development of treatment strategies. We support using the term 'atopic dermatitis' rather than eczema, because it describes the allergic background and inflammation ('itis') as drivers of the disease. Atopic dermatitis has many morphologic manifestations that vary by topographic area affected, age, or race and require consideration in differential diagnosis. Different phenotypes based on morphology and topographic location, ethnicity, and age are discussed. A better-defined phenotype identification for atopic dermatitis will facilitate earlier and correct diagnosis of this complex condition and inform selection of the most appropriate treatment choice in an era in which targeted therapies may generate more individualized patient care.

Gene Expression Comparison between Sézary Syndrome and Lymphocytic-Variant Hypereosinophilic Syndrome Refines Biomarkers for Sézary Syndrome

Sézary syndrome (SS), an aggressive cutaneous T-cell lymphoma (CTCL) with poor prognosis, is characterized by the clinical hallmarks of circulating malignant T cells, erythroderma and lymphadenopathy. However, highly variable clinical skin manifestations and similarities with benign mimickers can lead to significant diagnostic delay and inappropriate therapy that can lead to disease progression and mortality. SS has been the focus of numerous transcriptomic-profiling studies to identify sensitive and specific diagnostic and prognostic biomarkers. Benign inflammatory disease controls (e.g., psoriasis, atopic dermatitis) have served to identify chronic inflammatory phenotypes in gene expression profiles, but provide limited insight into the lymphoproliferative and oncogenic roles of abnormal gene expression in SS. This perspective was recently clarified by a transcriptome meta-analysis comparing SS and lymphocytic-variant hypereosinophilic syndrome, a benign yet often clonal T-cell lymphoproliferation, with clinical features similar to SS. Here we review the rationale for selecting lymphocytic-variant hypereosinophilic syndrome (L-HES) as a disease control for SS, and discuss differentially expressed genes that may distinguish benign from malignant lymphoproliferative phenotypes, including additional context from prior gene expression studies to improve understanding of genes important in SS.

Single-Cell Heterogeneity of Cutaneous T-Cell Lymphomas Revealed Using RNA-Seq Technologies

Cutaneous T-cell lymphomas (CTCLs) represent a large, heterogeneous group of non-Hodgkin lymphomas that primarily affect the skin. Among multiple CTCL variants, the most prevalent types are mycosis fungoides (MF) and Sézary syndrome (SS). In the past decade, the molecular genetics of CTCL have been the target of intense study, increasing the knowledge of CTCL genomic alterations, discovering novel biomarkers, and potential targets for patient-specific therapy. However, the detailed pathogenesis of CTCL development still needs to be discovered. This review aims to summarize the novel insights into molecular heterogeneity of malignant cells using high-throughput technologies, such as RNA sequencing and single-cell RNA sequencing, which might be useful to identify tumour-specific molecular signatures and, therefore, offer guidance for therapy, diagnosis, and prognosis of CTCL.

Pathogenesis and Therapy of Primary Cutaneous T-Cell Lymphoma: Collegium Internationale Allergologicum (CIA) Update 2020

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous disease group of unknown etiology with a complex immunological background. As CTCL arises from T cells that have a vital role in the antitumor response, their therapy is largely aimed at reversing the immunological mechanisms leading to or manifesting during this malignancy. Early disease stages can be controlled with skin-directed therapy in most CTCL cases. Still, advanced CTCL has a dismal prognosis and warrants systemic therapy. Despite considerable progress in understanding the pathophysiology of the disease and the numerous systemic treatment options available, long-term remission rates with conventional treatments alone are still low. Allogeneic hematopoietic stem cell transplantation is currently the only curative option for advanced CTCL, including mycosis fungoides and Sézary syndrome. The aims of this review is to summarize the recent findings on the immunology of this heterogeneous disease and to present the advances in its clinical management.

Selective inhibition of HDAC6 sensitizes cutaneous T-cell lymphoma to PI3K inhibitors

Histone deacetylase (HDAC) inhibitors, approved for the treatment of cutaneous T-cell lymphoma (CTCL), are non-selective agents associated with an unsatisfactory response and considerable side-effects. Targeting single HDAC isoforms is considered to provide novel therapeutic options. HDAC6 is overexpressed in primary samples from patients with CTCL and preclinical studies using transgenic mice that spontaneously develop a CTCL-like disease, have suggested that combinations including HDAC6 inhibitors may be successful in the treatment of CTCL. PI3K inhibition is currently being tested in clinical trials for CTCL with promising results. Since HDAC6 is known to diminish the activity of Akt via its deacetylation, the aim of the present study was to evaluate the therapeutic potential of selective HDAC6 inhibitors in combination with PI3K inhibitors in CTCL. Through the genetic and pharmacological inhibition of HDAC6, it was demonstrated that combining HDAC6 with PI3K inhibition may be an attractive therapeutic option for patients with CTCL.

Consensus on the Clinical Approach to Moderate-to-Severe Atopic Dermatitis in Spain: A Delphi Survey

BACKGROUND

The purpose of this study was to gather information on the current assessment and management of patients with moderate-to-severe AD in routine daily practice.

METHODS

A cross-sectional two-round Delphi survey with the participation of dermatologists and allergologists throughout Spain was conducted. They completed a 46-item questionnaire, and consensus was defined when responses of ≥80% of participants coincided in the categories of a 5-point Likert scale for that item.

RESULTS

A total of 105 specialists (aged 40-59 years) completed the two rounds. Participants agreed regarding the consideration of AD as a multifaceted disease and the differences in clinical presentation of AD according to the patient's age. It is recommendable to perform a skin biopsy to exclude early stage T-cell cutaneous lymphoma, psoriasis, or dermatitis herpetiformis, among others (99.1%). Also, consensus was reached regarding the use of the SCORAD index to quantify the severity of the disease (86.7%), the use of wet wraps to increase the effect of topical corticosteroids (90.4%), the usefulness of proactive treatment during follow-up (85.6%) and tacrolimus ointment (91.2%) to reduce new flares, and the fact that crisaborole is not the treatment of choice for severe AD (92.4%). AD was not considered a contraindication for immunotherapy in patients with allergic respiratory diseases (92.4%). In patients with severe AD, the use of immune response modifier drugs (97.6%) or phototherapy (92.8%) does not sufficiently cover their treatment needs. Consensus was also obtained regarding the role of the new biologic drugs (93.6%) targeting cytokines involved in the Th2 inflammatory pathway (92.0%) and the potential role of dupilumab as first-line treatment (90.4%) in moderate-to-severe AD patients.

CONCLUSION

This study contributes a reference framework to the care of AD patients. There is no diagnostic test or biomarkers to direct treatment or to assess the severity of the disease, and many therapeutic challenges remain.

Blockade of programmed cell death protein 1 (PD-1) in Sézary syndrome reduces Th2 phenotype of non-tumoral T lymphocytes but may enhance tumor proliferation

Sézary syndrome (SS) is an aggressive leukemic variant of cutaneous T-cell lymphoma (L-CTCL) that arises from malignant clonally derived skin-homing CD4⁺ T cells. Based on advancements in our understanding of the mechanisms underlying L-CTCL, boosting the suppressed immune response emerges as a promising strategy in SS management. Immune checkpoint inhibitory molecules have already demonstrated efficacy in a wide spectrum of malignancies. Currently, agents targeting the programmed death-1 (PD-1) axis are under evaluation in L-CTCL. Here we investigated the expression of PD-1 and its ligands, PD-L1 and PD-L2 in blood and skin from patients with L-CTCL. We demonstrate that PD-1 expression is markedly increased on tumor T cells compared to non-tumor CD4⁺ T cells from SS patients and to CD4⁺ cells from healthy individuals. In contrast, PD-L1 shows decreased expression on tumor T cells, while PD-L2 expression is low without significant differences between these groups. Functional PD-1 blockade in vitro resulted in reduced Th2 phenotype of non-tumor T lymphocytes, but enhanced the proliferation of tumor T cells from SS patients. Our study sheds some light on the PD-1 axis in both peripheral blood and skin compartments in SS patients, which may be relevant for the treatment of L-CTCL with immune checkpoint inhibitor.

Monoclonal Antibodies in Dermatooncology-State of the Art and Future Perspectives

Monoclonal antibodies (mAbs) targeting specific proteins are currently the most popular form of immunotherapy used in the treatment of cancer and other non-malignant diseases. Since the first approval of anti-CD20 mAb rituximab in 1997 for the treatment of B-cell malignancies, the market is continuously booming and the clinically used mAbs have undergone a remarkable evolution. Novel molecular targets are constantly emerging and the development of genetic engineering have facilitated the introduction of modified mAbs with improved safety and increased capabilities to activate the effector mechanisms of the immune system. Next to their remarkable success in hematooncology, mAbs have also an already established role in the treatment of solid malignancies. The recent development of mAbs targeting the immune checkpoints has opened new avenues for the use of this form of immunotherapy, also in the immune-rich milieu of the skin. In this review we aim at presenting a comprehensive view of mAbs' application in the modern treatment of skin cancer. We present the characteristics and efficacy of mAbs currently used in dermatooncology and summarize the recent clinical trials in the field. We discuss the side effects and strategies for their managing.

The role of the dermatologist in the immune-mediated/allergic diseases - position statement of the EADV task force on contact dermatitis, EADV task force on occupational skin diseases, UEMS-EBDV subcommission allergology and European Dermatology Forum

BACKGROUND

The members of the Task Force on Contact Dermatitis and the Task Force on Occupational Dermatoses of the European Academy of Dermatology and Venereology (EADV), of the European Dermatology Forum (EDF), and the members of the UEMS Section of Dermatology-Venereology (UEMS-EBDV) we want to vindicate the fundamental role that the specialist in Dermatology has in the diagnosis and management of Immuno-mediated /allergic Diseases.

OBJECTIVE

In disagreement with the blueprint paper of the UEMS section of Allergology (2013), in which dermatologists are excluded from one of their core activities it was decided to write this consensus paper.

DISCUSSION

The skin occupies a crucial place in the broad spectrum of allergic diseases; there is no other organ with such a multitude of different clinical conditions mediated by so many pathogenetic immune mechanisms. Subsequently, dermatologists play a fundamental role in the management of immune-mediated diseases including among others contact dermatitis, atopic dermatitis, urticaria and angioedema or cutaneous adverse drug, food and arthropod reactions. The essential role of dermatology in the diagnostic, therapeutic and preventive management of immune mediated /allergic diseases which is crucial for patient management is justified from both the academic and professional point of view.

CONCLUSION

Based on the best care of the patient with cutaneous immune allergic disease a multidisciplinary approach is desirable and the dermatologist has a pivotal role in patient management. Be so good and no one will not ignore you, dermatologist. Ideally Dermatology should be governed according the following Henry Ford statement: "Arriving together is the beginning; keeping together is progress; working together is success."

Nonlesional atopic dermatitis skin shares similar T-cell clones with lesional tissues

BACKGROUND

Atopic dermatitis (AD) is characterized by robust immune activation. Various T-cell subsets, including Th2/Th22 cells, are increased in lesional and nonlesional skin. However, there is conflicting literature on the diversity of the T-cell receptor (TCR) repertoire in lesional AD, and its relation to nonlesional skin remains unclear.

METHODS

We performed high-throughput deep sequencing of the β-TCR repertoire in 29 lesional and 19 nonlesional AD biopsies, compared to six healthy control and six cutaneous T-cell lymphoma (CTCL) samples from previously published cohorts.

RESULTS

While greater T-cell infiltrates were observed in lesional vs nonlesional AD, TCR repertoire diversity was similar in lesional and nonlesional tissues, and absolute numbers of unique T-cell clones correlated with respective T-cell counts. Most (87%) top expanded lesional T-cell clones were shared with nonlesional tissues, and they were largely maintained after 16 weeks of successful treatment with topical triamcinolone. Nevertheless, both lesional and nonlesional AD showed a highly polyclonal TCR pattern, without evidence of oligoclonal expansion, or a preferred usage of certain V-β genes in AD skin. Size of the overall T-cell infiltrate, but not the level of clonality, correlated with mRNA levels of key inflammatory mediators (e.g., IL-13, CCL17, IL23p19, CXCL10).

CONCLUSION

While AD harbors a highly polyclonal T-cell receptor repertoire, and despite the lack of information on TCR antigen specificity, the sharing of top abundant clones between lesional and nonlesional skin, and their persistence after months of therapy, points to the continuous presence of potentially pathogenic skin resident memory T cells well beyond clinically inflamed lesions.

TCR-CXCR4 signaling stabilizes cytokine mRNA transcripts via a PREX1-Rac1 pathway: implications for CTCL

As with many immunopathologically driven diseases, the malignant T cells of cutaneous T-cell lymphomas (CTCLs), such as Sézary syndrome, display aberrant cytokine secretion patterns that contribute to pathology and disease progression. Targeting this disordered release of cytokines is complicated by the changing cytokine milieu that drives the phenotypic changes of CTCLs. Here, we characterize a novel signaling pathway that can be targeted to inhibit the secretion of cytokines by modulating either CXCR4 or CXCR4-mediated signaling. We demonstrate that upon ligation of the T-cell antigen receptor (TCR), the TCR associates with and transactivates CXCR4 via phosphorylation of S339-CXCR4 in order to activate a PREX1-Rac1-signaling pathway that stabilizes interleukin-2(IL-2), IL-4, and IL-10 messenger RNA (mRNA) transcripts. Pharmacologic inhibition of either TCR-CXCR4 complex formation or PREX1-Rac1 signaling in primary human T cells decreased mRNA stability and inhibited secretion of IL-2, IL-4, and IL-10. Applying this knowledge to Sézary syndrome, we demonstrate that targeting various aspects of this signaling pathway blocks both TCR-dependent and TCR-independent cytokine secretion from a Sézary syndrome-derived cell line and patient isolates. Together, these results identify multiple aspects of a novel TCR-CXCR4-signaling pathway that could be targeted to inhibit the aberrant cytokine secretion that drives the immunopathogenesis of Sézary syndrome and other immunopathological diseases.