Past, present, and future for biologic intervention in atopic dermatitis

Blockade of OSMRβ signaling ameliorates skin lesions in a mouse model of human atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by severe pruritus and eczematous skin lesions. Although IL-31, a type 2 helper T (Th2)-derived cytokine, is important to the development of pruritus and skin lesions in AD, the blockade of IL-31 signaling does not improve the skin lesions in AD. Oncostatin M (OSM), a member of IL-6 family of cytokines, plays important roles in the regulation of various inflammatory responses through OSM receptor β subunit (OSMRβ), a common receptor subunit for OSM and IL-31. However, the effects of OSM on the pathogenesis of AD remain to be elucidated. When AD model mice were treated with OSM, skin lesions were exacerbated and IL-4 production was increased in the lymph nodes. Next, we investigated the effects of the monoclonal antibody (mAb) against OSMRβ on the pathogenesis of AD. Treatment with the anti-OSMRβ mAb (7D2) reduced skin severity score in AD model mice. In addition to skin lesions, scratching behavior was decreased by 7D2 mAb with the reduction in the number of OSMRβ-positive neurons in the dorsal root ganglia of AD model mice. 7D2 mAb also reduced the serum concentration of IL-4, IL-13, and IgE as well as the gene expressions of IL-4 and IL-13 in the lymph nodes of AD model mice. Blockade of both IL-31 and OSM signaling is suggested to suppress both pruritus and Th2 responses, resulting in the improvement of skin lesions in AD. The anti-OSMRβ mAb may be a new therapeutic candidate for the treatment of AD.

T-helper-2 cells and atopic disease: lessons learnt from inborn errors of immunity

Inborn errors of immunity (IEI) are caused by monogenic variants that affect the host response to bacterial, viral, and fungal pathogens. As such, individuals with IEI often present with severe, recurrent, and life-threatening infections. However, the spectrum of disease due to IEI is very broad and extends to include autoimmunity, malignancy, and atopic diseases such as eczema, atopic dermatitis, and food and environmental allergies. Here, I review IEI that affect cytokine signaling pathways that dysregulate CD4⁺ T-cell differentiation, resulting in increased T-helper-2 (Th2) cell development, function, and pathogenicity. These are elegant examples of how rare IEI can provide unique insights into more common pathologies such as allergic disease that are impacting the general population at increased frequency.

Mesenchymal Stem Cells Profile in Adult Atopic Dermatitis and Effect of IL4-IL13 Inflammatory Pathway Inhibition In Vivo: Prospective Case-Control Study

Atopic dermatitis (AD) is an inflammatory disease that typically begins in childhood and may persist into adulthood, becoming a lifelong condition. The major inflammatory mediators of AD are known to be interleukin IL4 and IL13, so Dupilumab, which is able to inhibit both interleukins by blocking the shared IL4Rα subunit, has become an attractive option for treating AD. Mesenchymal stem cells (MSCs) are involved in the onset and development of AD by secreting specific interleukins. The aim of this study was to isolate MSCs from healthy controls (C-MSCs) and patients with AD before (AD-MSCs T0) and after 16 weeks of treatment with Dupilumab (AD-MSCs T16); to evaluate the expression mainly of IL4 and IL13 and of other inflammatory cytokines in C-MSCs, AD-MSCs at T0 and at T16; and to evaluate the efficacy of Dupilumab on MSCs immunobiology. C- and AD-MSCs (T0, T16) were isolated from skin specimens and characterized; the expression/secretion of IL4 and IL13 was evaluated using immuno-cytochemistry (ICC), indirect immune-fluorescence (IIF) and an ELISA test; secretion of IL2, IL4, IL5, IL6, IL10, IL12, IL13, IL17A, Interferon gamma (IFNγ), Tumor necrosis factor alpha (TNFα), Granulocyte Colony-Stimulating Factor (G-CSF), and Transforming Growth Factor beta1 (TGFβ1) were measured with ELISA. IL13 and IL6 were over-expressed, while IL4 was down-regulated in AD-MSCs at T0 compared to C-MSCs. IL6 and IL13 expression was restored after 16 weeks of Dupilumab treatment, while no significant effects on IL4 expression were noted. Finally, IL2, IL5, IL10, IL12, IL17A, INFγ, TNFα, G-CSF, and TGFβ1 were similarly secreted by C- and AD-MSCs. Although Dupilumab blocks the IL4Rα subunit shared by IL4 and IL13, it is evident that its real target is IL13, and its ability to target IL13 in MSCs reinforces the evidence, already known in differentiated cells, of the central role IL13 rather than IL4 in the development of AD. The inflammatory cascade in AD begins at the mesenchymal level, so an upstream therapeutic intervention, able to modify the immunobiology of atopic MSCs, could potentially change the natural history of the disease.

Galectin-9 contributes to the pathogenesis of atopic dermatitis via T cell immunoglobulin mucin-3

Background

Atopic dermatitis (AD), a common type 2 inflammatory disease, is driven by T helper (T_H) 2/T_H22polarization and cytokines.Galectin-9 (Gal-9), via its receptor T cell immunoglobulin- and mucin-domain-containing molecule-3 (TIM-3), can promote T_H2/T_H22 immunity. The relevance of this in AD is largely unclear.

Objectives

To characterize the role of TIM-3 and Gal-9 in the pathogenesis of AD and underlying mechanisms.

Methods

We assessed the expression of Gal-9 and TIM-3 in 30 AD patients, to compare them with those of 30 healthy controls (HC) and to explore possible links with disease features including AD activity (SCORAD), IgE levels, and circulating eosinophils and B cells. We also determined the effects of Gal-9 on T cells from the AD patients.

Results

Our AD patients had markedly higher levels of serum Gal-9 and circulating TIM-3-expressing T_H1 and T_H17 cells than HC. Gal-9 and TIM-3 were linked to high disease activity, IgE levels, and circulating eosinophils and/or B cells. The rates of circulating TIM-3-positive CD4⁺ cells were positively correlated with rates of T_H2/T_H22 cells and negatively correlated with rates of T_H1/T_H17 cells. Gal-9 inhibited the proliferation and induced the apoptosis of T cells in patients with AD, especially in those with severe AD.

Conclusion

Our findings suggest thatGal-9, via TIM-3, contributes to the pathogenesis of AD by augmenting T_H2/T_H22 polarization through the downregulation of T_H1/T_H17immunity. This makes Gal-9 and TIM-3 interesting to explore further, as possible drivers of disease and targets of novel AD treatment.

Current and Emerging Strategies to Inhibit Type 2 Inflammation in Atopic Dermatitis

Type 2 immunity evolved to combat helminth infections by orchestrating a combined protective response of innate and adaptive immune cells and promotion of parasitic worm destruction or expulsion, wound repair, and barrier function. Aberrant type 2 immune responses are associated with allergic conditions characterized by chronic tissue inflammation, including atopic dermatitis (AD) and asthma. Signature cytokines of type 2 immunity include interleukin (IL)-4, IL-5, IL-9, IL-13, and IL-31, mainly secreted from immune cells, as well as IL-25, IL-33, and thymic stromal lymphopoietin, mainly secreted from tissue cells, particularly epithelial cells. IL-4 and IL-13 are key players mediating the prototypical type 2 response; IL-4 initiates and promotes differentiation and proliferation of naïve T-helper (Th) cells toward a Th2 cell phenotype, whereas IL-13 has a pleiotropic effect on type 2 inflammation, including, together with IL-4, decreased barrier function. Both cytokines are implicated in B-cell isotype class switching to generate immunoglobulin E, tissue fibrosis, and pruritus. IL-5, a key regulator of eosinophils, is responsible for eosinophil growth, differentiation, survival, and mobilization. In AD, IL-4, IL-13, and IL-31 are associated with sensory nerve sensitization and itch, leading to scratching that further exacerbates inflammation and barrier dysfunction. Various strategies have emerged to suppress type 2 inflammation, including biologics targeting cytokines or their receptors, and Janus kinase inhibitors that block intracellular cytokine signaling pathways. Here we review type 2 inflammation, its role in inflammatory diseases, and current and future therapies targeting type 2 pathways, with a focus on AD.

The efficacy and safety of JAK inhibitors for atopic dermatitis: a systematic review and meta-analysis

BACKGROUND

Atopic dermatitis (AD) is one of the serious global problems. There were wide concerns about whether Janus kinase (JAK) inhibitor was an alternative treatment for AD.

METHOD

Eight databases were searched from the earliest publication date available to January 2, 2021. We included randomized controlled trials comparing JAK inhibitors with control treatment for AD. Data were pooled using Stata.14 software and performed as mean differences (MD) and risk ratios (RR) with 95% CIs. We did subgroup analysis based on specific outcomes.

RESULTS

A total of studies, ten randomized controlled trials, with 2583 patients were included in the final synthesis. This meta-analysis showed JAK inhibitor resulted in significant improvement on EASI total score (MD = -0.31; 95%CI, -0.46 to -0.17; p = .000; I² = 90.0%, p = .000) and pruritus numerical rating scale (NRS) score (MD = -1.15; 95%CI, -1.48 to -0.83; p = .000; I² = 95.9%, p = .000), without the higher risk of total adverse effects (RR = 1.02; 95%CI, 0.90-1.16; p = .745; I² =27.9%, p = .206).

CONCLUSIONS

JAK inhibitor was a promising option for atopic dermatitis. More data and surveillance will be needed to identify efficacy, safety, and the risk of adverse effects.

Impact of Atopic Dermatitis and Chronic Hand Eczema on Quality of Life Compared With Other Chronic Diseases

: The aim of this study was to conduct 3 literature reviews to examine the impact of atopic dermatitis (AD) and chronic hand eczema (CHE) on health-related quality of life (HRQoL) compared with other chronic conditions by comparing reported utility scores of 4 commonly used generic HRQoL instruments. A systematic search was performed using PubMed, ScienceDirect, MEDLINE, EMBASE, Health Technology Assessment database, and ScHARRHUD. Inclusion criteria included, but were not limited to, patients of any age, studies from any location, publications reporting utility data based on EuroQoL 5 dimensions, the EuroQoL 5-dimension Visual Analog Scale, the Short-Form Health Survey, and the Short-Form 6 Dimensions in the English language. Inclusion criteria were met by 16 articles for AD, 25 articles for chronic conditions, and 9 articles for CHE. The findings of this review highlight that the disutility and loss in HRQoL of patients with AD and CHE are similar to or higher than other chronic conditions, such as cancer or hepatitis.

The effectiveness of Janus kinase inhibitors in treating atopic dermatitis: A systematic review and meta-analysis

Primary studies have presented conflicting results on the efficacy of Janus kinase (JAK) inhibitors in treating atopic dermatitis. Hence, it is important to determine the summary effect of JAK inhibitors in order to guide the clinical application of this potentially beneficial drug. To determine the efficacy of JAK inhibitors in treating atopic dermatitis in all age groups. A systematic review with meta-analyses of randomized controlled trials (RCTs) reporting on the effect of JAK inhibitors on the signs and symptoms of atopic dermatitis were conducted. Six electronic databases, registries, and search engines (PubMed, Cochrane Central Register of Controlled Trials [CENTRAL], Google Scholar, ScienceDirect, Clinical.gov, and WHO ICTRP) were searched from inception to September, 2019. The search terms include "atopic dermatitis," "eczema," and "Janus kinase inhibitor." The search was restricted to humans. A total of 413 studies were identified through the database search and hand-searching. After the selection process, five RCTs were included in this systematic review. A meta-analysis of three studies showed that JAK inhibitors were effective in reducing Eczema Area and Severity Index (P = .0001) and pruritus scores (P = .0001). JAK inhibitors appear to be effective in treating atopic dermatitis. Future studies should aim to evaluate its cost-effectiveness and availability to patients especially in developing countries.

Childhood atopic dermatitis: current developments, treatment approaches, and future expectations

Atopic dermatitis (AD) is the most common chronic inflammatory skin disorder of childhood. Underlying factors that contribute to AD are impaired epithelial barrier, alterations in the lipid composition of the skin, immunological imbalance including increased Th2/Th1 ratio, proinflammatory cytokines, decreased T regulatory cells, genetic mutations, and epigenetic alterations. Atopic dermatitis is a multifactorial disease with a particularly complicated pathophysiology. Discoveries to date may be considered the tip of the iceberg, and the increasing number of studies in this field indicate that there are many points to be elucidated in AD pathophysiology. In this review, we aimed to illustrate the current understanding of the underlying pathogenic mechanisms in AD, to evaluate available treatment options with a focus on recently discovered therapeutic agents, and to determine the personal, familial, and economic burdens of the disease, which are frequently neglected issues in AD. Currently available therapies only provide transient solutions and cannot fully cure the disease. However, advances in the understanding of the pathogenic mechanisms of the disease have led to the production of new treatment options, while ongoing drug trials also have had promising results.

Understanding economic evidence for the prevention and treatment of atopic eczema

Background

Atopic eczema is an inflammatory skin condition, with a similar impact on health‐related quality of life as other chronic diseases. Increasing pressures on resources within the National Health Service increase the importance of having good economic evidence to inform their allocation.

Objectives

To educate dermatologists about economic methods with reference to currently available economic evidence on eczema.

Methods

The role of different types of economic evidence is illustrated by evidence found in a systematic literature search conducted across 12 online databases up to 22 May 2017. Primary empirical studies either reporting the results of a cost‐of‐illness study or evaluating the cost, utility or full economic evaluation of interventions for preventing or treating eczema were included. Two reviewers independently assessed studies for eligibility and performed data abstraction, with disagreements resolved by a third reviewer. Evidence tables of results were produced for narrative discussion. The reporting quality of economic evaluations was assessed.

Results

Seventy‐eight studies (described in 80 papers) were deemed eligible. Thirty‐three (42%) were judged to be economic evaluations, 12 (15%) cost analyses, six (8%) utility analyses, 26 (33%) cost‐of‐illness studies and one a feasibility study (1%). The calcineurin inhibitors tacrolimus and pimecrolimus, as well as barrier creams, had the most economic evidence available. Partially hydrolysed infant formula was the most commonly evaluated prevention.

Conclusions

The current level of economic evidence for interventions aimed at preventing and treating eczema is limited compared with that available for clinical outcomes, suggesting that greater collaboration between clinicians and economists might be beneficial.

What's already known about this topic?

Resources available for health care are limited and their efficient allocation should be informed by robust economic evidence about value for money.

The scale and quality of economic evidence available for atopic eczema has not previously been examined.

What does this study add?

By comparison with the considerable clinical evidence for interventions to prevent and treat eczema, there is limited economic evidence available.

The economic evidence available is limited in scope with regard to the types and range of interventions evaluated.

The quality of future economic studies could be improved by greater collaboration between economists and clinicians.

https://doi.org/10.1111/bjd.18391 available online

Einsatz und Wirksamkeit von Systemtherapien bei Erwachsenen mit schwerer Neurodermitis: Erste Ergebnisse des deutschen Neurodermitis-Registers TREATgermany

HINTERGRUND

Versorgungsregister dienen der Erfassung des Einsatzes und der Wirksamkeit von Therapien unter realen Versorgungsbedingungen und sind als Basis einer evidenzbasierten Gesundheitsversorgung unverzichtbar.

METHODIK

Das deutsche Neurodermitis-Register TREATgermany wurde als weltweit erstes Register für Patienten mit schwerer Neurodermitis 2011 initiiert. Erwachsene mit schwerer Neurodermitis (aktuelle/frühere antientzündliche Systemtherapie und/oder objektiver SCORAD ≥ 40) werden über einen Zeitraum von 24 Monaten prospektiv beobachtet. Anhand validierter Erhebungsinstrumente werden die klinische Erkrankungsschwere (EASI, SCORAD), Lebensqualität (DLQI), Symptome, globale Erkrankungsschwere sowie die Patientenzufriedenheit erfasst und die durchgeführten Therapien dokumentiert. Die vorliegende Analyse beschreibt die Charakteristika, Therapiewahl und Wirksamkeit der eingesetzten antiinflammatorischen Systemtherapien der bis Oktober 2014 eingeschlossenen Patienten.

ERGEBNISSE

An fünf Zentren wurden insgesamt 78 Patienten (Durchschnittsalter 39 Jahre, 61 % männlich) eingeschlossen. Bei den Patienten besteht eine hohe Inanspruchnahme ambulanter und stationärer Leistungen. Ciclosporin war das am häufigsten eingesetzte Systemtherapeutikum und zeigte die höchste klinische Effektivität (EASI-50-Ansprechrate 51 %; EASI-75-Ansprechrate 34 % nach zwölfwöchiger Therapie). Azathioprin, Methotrexat (MTX), Prednisolon oral, Mycophenolat, Alitretinoin und Leflunomid wurden ebenfalls bei einzelnen Patienten eingesetzt.

SCHLUSSFOLGERUNGEN

Die vorliegende Registerauswertung gibt wichtige Hinweise zur derzeitigen Versorgung von Erwachsenen mit schwerer Neurodermitis in Deutschland, dokumentiert die hohe Erkrankungslast, den Nutzen vorhandener Therapien und den Bedarf an weiteren, effektiven und in der Langzeitanwendung sicheren Therapieoptionen.

Langerhans and inflammatory dendritic epidermal cells in atopic dermatitis are tolerized toward TLR2 activation

BACKGROUND

The skin of atopic dermatitis (AD) patients presents a significant dysbalance of the microbiome with a high colonization by Staphylococcus aureus (S. aureus), which positively correlates with the severity of the disease.

OBJECTIVE

Understanding the role of epidermal dendritic cells (DC) as link between the innate and the adaptive immune systems in AD.

METHODS

Comparative phenotypic and functional analysis of TLR2 on Langerhans cells (LC) and inflammatory dendritic epidermal cells (IDEC) in organotypic models as well as freshly isolated cells from healthy and AD skin.

RESULTS

In situ analysis of freshly isolated LC and IDEC from AD skin revealed decreased TLR2 expression compared to LC from healthy skin. In contrast to IDEC, LC from AD skin failed to display any evidence for in situ activation. Exposure to TLR2 ligand Pam3Cys resulted in maturation and increased migratory activity of LC from normal skin. LC and IDEC from AD were unresponsive to TLR2 ligand in that they failed to mature and displayed a high spontaneous migratory activity. Keratinocytes from both healthy and AD skin expressed similar levels of TLR2. The production of IL-6 and IL-10 was impaired by Pam3Cys in supernatants from AD skin. IL-18 was significantly higher in supernatants from AD skin and not influenced by TLR2 ligation, when compared to healthy skin.

CONCLUSION

Our results suggest that TLR2-mediated sensing of S. aureus-derived signals is strongly impaired in LC from AD skin. This phenomenon may partly contribute to the immune deviation in AD and the lack of S. aureus clearance.

Immune-modulation via IgD B-cell receptor suppresses allergic skin inflammation in experimental contact hypersensitivity models despite of a Th2-favoured humoral response

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) are common skin inflammatory conditions. B and T cells are strongly implicated in allergic contact hypersensitivity (CHS) conditions. Activation of IgD B-cell receptor (BCR) by anti-IgD stimulation depletes mature B cells and modulates T-helper cell type 1/2 (Th1/2) responses in vivo. It is not known whether these effects by anti-IgD exacerbates or ameliorates chronic skin inflammations. This study investigated the effects of anti-IgD and B-cell depleting anti-CD20 antibody on skin inflammation in CHS murine models. Chronic CHS were induced by challenges with allergens trimellitic anhydride (TMA) or 2,4 dinitrochlorobenzene (DNCB). Mice were treated with an anti-IgD or anti-CD20 at various time-points following allergen challenges. This study revealed that early therapeutic treatments with anti-IgD at 4 h after allergen challenge significantly reduced skin inflammation in both TMA- and DNCB-induced CHS models (P < 0.05). In contrast, anti-CD20 treatment exacerbated skin inflammation in DNCB-induced CHS despite of an extensive B cell depletion (P < 0.05). Anti-IgD treatment depleted mature CD19⁺IgD⁺ B cells but enhanced allergen-specific IgM and total IgE productions, suggesting a Th2-favoured humoral response. Anti-IgD reduced neutrophilic infiltrations but increases accumulation of mast cells in dermal tissues. The anti-inflammatory effects of anti-IgD were supported by evidence of an increase in the percentage of regulatory B cells and T cells. Collectively, this study demonstrates that immune-modulation by anti-IgD treatment suppresses Th2-mediated allergic skin inflammation in murine models despite a skew toward a Th2-favvoured humoral response and therefore may present a novel treatment for chronic human AD and ACD.

Changing perspectives in atopic dermatitis

Atopic dermatitis (AD) is a multifaceted disease that involves a complex interplay between the skin and the immune system. The course of the disease depends strongly on the genetic background of the patient and on yet poorly-defined environmental factors. Changes in lifestyle could be behind the dramatic rise in the prevalence of AD across continents; including hygienic conditions, food, social habits, skin microbiome or exposure to a number of allergens. Although AD typically develops in childhood and disappears after a few years, in a relatively large number of patients it continues into adulthood. Adult AD can also appear de novo but it is often underdiagnosed and its treatment can be challenging. New, highly effective drugs are being developed to manage moderate and severe forms of the disease in adults. In this review, we highlight the most recent developments in diagnostic tools, current insights into the mechanistic basis of this disease, and therapeutic innovations.

New biologics for allergic diseases

INTRODUCTION

Allergic conditions such as asthma and atopic dermatitis have a high prevalence but represent a heterogeneous group of diseases despite similar clinical presentation and underlying pathophysiology. A better understanding of the phenotypes and endotypes of these diseases has driven rapid development of biologic medications targeting many steps of the inflammatory pathways. Areas covered: There are 2 major inflammatory pathways that drive allergic diseases: Type-2 (Th-2) inflammation and non-type 2 inflammation. All of the biologic medications currently approved for use, and most of the biologic medications under development for allergic diseases have focused on the Th-2 inflammatory pathway. Biologic targets along this pathway include Anti-Immunoglobulin E (IgE), Anti-Interleukin 5 (IL-5), Anti-IL 4, and Anti-IL 13. Although the most study has been done in the realm of severe asthma, biologic targets for other allergic diseases including atopic dermatitis, chronic rhinosinusitis with nasal polyposis, chronic idiopathic urticaria, eosinophilic esophagitis, and eosinophilic granulomatosis with polyangiitis are also discussed. Expert commentary: Novel biologic therapies have emerged over the last several years that have revolutionized the management of patients with refractory allergic disease.

Biological Therapeutic Treatment of Atopic Dermatitis

Atopic dermatitis is a chronic recurrent inflammatory disease caused, inter alia, by violations of the barrier function of the skin and pathological immune response in the form of an imbalance of Th1 and Th2 lymphocytes with increased production of IL-4, IL-5, IL-13, IL-31. Treatment of severe forms of atopic dermatitis is not an easy task due to the variability of the individual response to treatment, the short duration of the therapeutic effect and the frequent development of undesirable phenomena associated with the use of existing methods of systemic immunosuppressive therapy. The study of the pathogenesis of atopic dermatitis made it possible to identify the spectrum of molecular targets, providing the basis for researching alternative variants to the previously used systemic therapy methods – genetic engineering biological preparations. Contemporary data on the pathogenesis of atopic dermatitis as well as potential molecular targets for innovative biological preparations, the efficacy of which has been evaluated through clinical trials, are presented in the review. 

A molecular mechanism for IL-4 suppression of loricrin transcription in epidermal keratinocytes: implication for atopic dermatitis pathogenesis

Skin barrier defects play an important role in atopic dermatitis (AD) pathogenesis. Loricrin, an important barrier protein suppressed in human AD, is down-regulated by IL-4 in keratinocytes. However, the molecular mechanism is unknown. Since loricrin transcription requires p300/CBP, and Stat6 also recruits this common coactivator for its stimulated factors, we hypothesize that IL-4-activated Stat6 competes for the available endogenous p300/CBP, leading to loricrin transcription inhibition. First, we showed that loricrin is suppressed in the skin of IL-4 transgenic mice, an AD mouse model. In human keratinocytes, IL-4 down-regulation of loricrin is abrogated by a pan-Jak inhibitor, suggesting that the Jak-Stat pathway is involved. To further investigate the downstream molecular mechanism, we transfected HaCat cells with a loricrin promoter and then treated them with either IL-4 or vehicle. Not surprisingly, IL-4 greatly suppressed the promoter activity. Interestingly, this suppression was prevented when we knocked down Stat6, indicating that Stat6 participates in IL-4 regulation of loricrin. A Stat6-specific inhibitor confirmed the knockdown study. Finally, IL-4 suppression of loricrin was reversed with transfection of a CBP expression vector in a dose-dependent manner. Taken together, for the first time, we delineate a molecular mechanism for IL-4 down-regulation of loricin expression in human keratinocytes, which may play an important role in AD pathogenesis.

New and emerging targeted systemic therapies: a new era for atopic dermatitis

PURPOSE

This is a review of emerging targeted, systemic therapies for atopic dermatitis (AD). The information presented aims to provide dermatologists with updated therapeutic options, stimulate academic interest, and spark future research.

MATERIAL AND METHODS

Extensive search of ClinicalTrials.gov, the National Eczema Association, and PubMed was performed for clinical trials examining the effect of emerging targeted, systemic therapies in patients with AD. Results were included if they demonstrated efficacy in reversing AD symptoms. Studies that did not demonstrate clinical benefit were excluded.

RESULTS

A number of emerging systemic agents targeting specific mediators involved in the pathogenesis of AD were found. These targets include IL-4, IL-13, IgE, B-cells, IL-5, IL-31, JAK-STAT, SYK, IL-6, PDE-4, IL-12, IL-17, IL-23, IL-22, H4R, NKR1, κOR, TSLP, PPAR-γ, and DGLA. Treatment of AD patients with these therapies has, in many cases, led to statistically significant improvements in clinical severity scores and patient-reported outcomes.

CONCLUSIONS

While multiple agents have demonstrated efficacy, only dupilumab is currently approved for adults with AD. Large-scale, randomized, placebo-controlled, double-blind trials, especially in children, are needed. As we enter the dawn of targeted therapy for AD, a comprehensive clinical trial registry is needed to facilitate data pooling and comparison among international registries.

Clinical phenotypes and endophenotypes of atopic dermatitis: Where are we, and where should we go?

Atopic dermatitis (AD) is a paradigmatic chronic inflammatory skin disease characterized by a complex pathophysiology and a wide spectrum of the clinical phenotype. Despite this high degree of heterogeneity, AD is still considered a single disease and usually treated according to the "one-size-fits-all" approach. Thus more tailored prevention and therapeutic strategies are still lacking. As for other disciplines, such as oncology or rheumatology, we have to approach AD in a more differentiated way (ie, to dissect and stratify the complex clinical phenotype into more homogeneous subgroups based on the endophenotype [panel of biomarkers]) with the aim to refine the management of this condition. Because we are now entering the era of personalized medicine, a systems biology approach merging the numerous clinical phenotypes with robust (ie, relevant and validated) biomarkers will be needed to best exploit their potential significance for the future molecular taxonomy of AD. This approach will not only allow an optimized prevention and treatment with the available drugs but also hopefully help assign newly developed medicinal products to those patients who will have the best benefit/risk ratio.

Cellular and molecular immunologic mechanisms in patients with atopic dermatitis

Atopic dermatitis (AD) is a complex skin disease frequently associated with other diseases of the atopic diathesis. Recent evidence supports the concept that AD can also recognize other comorbidities, such as chronic inflammatory bowel or cardiovascular diseases. These comorbidities might result from chronic cutaneous inflammation or from a common, yet-to-be-defined immunologic background leading to immune deviations. The activation of immune cells and their migration to the skin play an essential role in the pathogenesis of AD. In patients with AD, an underlying immune deviation might result in higher susceptibility of the skin to environmental factors. There is a high unmet medical need to define immunologic endotypes of AD because it has significant implications on upcoming stratification of the phenotype of AD and the resulting targeted therapies in the development of precision medicine. This review article emphasizes studies on environmental factors affecting AD development and novel biological agents used in the treatment of AD. Best evidence of the clinical efficacy of novel immunologic approaches using biological agents in patients with AD is available for the anti-IL-4 receptor α-chain antibody dupilumab, but a number of studies are currently ongoing with other specific antagonists to immune system players. These targeted molecules can be expressed on or drive the cellular players infiltrating the skin (eg, T lymphocytes, dendritic cells, or eosinophils). Such approaches can have immunomodulatory and thereby beneficial clinical effects on the overall skin condition, as well as on the underlying immune deviation that might play a role in comorbidities. An effect of these immunologic treatments on pruritus and the disturbed microbiome in patients with AD has other potential consequences for treatment.

Anti-allergic and Profilaggrin (ProFLG)-mRNA expression modulatory effects of sacran

Atopic dermatitis (AD) is a skin disorder characterized by filaggrin (FLG) defect. We evaluated sacran's effects on dust-mite extracts (DME)-induced AD-like disease and also its effect on profilaggrin (proFLG) in a murine model of 2,4-dinitroflurobenze (DNFB)-induced contact hypersensitivity. In the murine AD-like disease model, allergic NC/Nga mice (N=60) were randomly divided into five treatment groups of 12 animals each: 0.2% and 1%sacran; 0.1% Tacrolimus; Vaseline and buffer-treated controls. Blood samples were drawn and serum levels of representative Th-1, Th-2 and also Th-17 (IL-17A) cytokines were assayed by Cytometric Bead Array (CBA). In the contact hypersensitivity model, diseased NC/Nga mice (N=20) were divided into four groups of five mice each [0.05%sacran, 0.05% chondroitin sulfate (CS), 0.5% prednisolone (PD), non-treated control group] and were treated for 14days. Skin biopsies were performed for the measurement of proFLG-mRNA by real-time PCR. Sacran solutions and 0.1%Tacrolimus reduced disease severity, suppressed histological changes and decreased the serum Th-1 (IFN-γ, TNF-α, IL-2) and Th-2 (IL-4, IL-6, IL-10) cytokines in allergic mice (vs. controls). Additionally, a marked increase of proFLG-mRNA expression was observed in 0.05%sacran group (vs. control 0.05% CS and 0.5% PD groups). Thus, Sacran might be useful as a natural skin barrier enhancer and anti-allergic agent.

Psoriasis and Atopic Dermatitis

Psoriasis and atopic dermatitis are common, chronic inflammatory skin diseases. We discuss several aspects of these disorders, including: risk factors; incidence and prevalence; the complex disease burden; and the comorbidities that increase the clinical significance of each disorder. We also focus on treatment management strategies and outline why individualized, patient-centered treatment regimens should be part of the care plans for patients with either psoriasis or atopic dermatitis. Finally, we conclude that, while our theoretical knowledge of the optimum care plans for these patients is increasingly sophisticated, this understanding is, unfortunately, not always reflected in daily clinical practice.

The Pathogenetic Effect of Natural and Bacterial Toxins on Atopic Dermatitis

Atopic dermatitis (AD) is a common allergic skin disease that is associated with chronic, recurrent eczematous and pruritic lesions at the flexural folds caused by interacting factors related to environmental and immune system changes. AD results in dry skin, and immunoglobulin E-mediated allergic reactions to foods and environmental allergens. While steroids and anti-histamines temporarily relieve the symptoms of AD, the possibility of side effects from pharmacological interventions remains. Despite intensive research, the underlying mechanisms for AD have not been clarified. A study of Staphylococcus aureus (S. aureus) established the role of its toxins in the pathogenesis of AD. Approximately 90% of patients with AD experience S. aureus colonization and up to 50%–60% of the colonizing S. aureus is toxin-producing. Any damage to the protective skin barrier allows for the entry of invading allergens and pathogens that further drive the pathogenesis of AD. Some natural toxins (or their components) that have therapeutic effects on AD have been studied. In addition, recent studies on inflammasomes as one component of the innate immune system have been carried out. Additionally, studies on the close relationship between the activation of inflammasomes and toxins in AD have been reported. This review highlights the literature that discusses the pathogenesis of AD, the role of toxins in AD, and the positive and negative effects of toxins on AD. Lastly, suggestions are made regarding the role of inflammasomes in AD.

New opportunities and challenges in the assessment of drugs for atopic diseases

Atopic conditions (atopic dermatitis, rhinitis, and asthma) belong to the most common noncommunicable diseases and are driven by chronic inflammatory reactions. They have a strong impact on the quality of life and represent a substantial and growing socio-economic burden. Interestingly, there is an increasing interest in the development of new therapeutic options with a number of biologics and small molecules targeting potential key mechanisms in atopic conditions. However, besides the safety issue, most of the new active substances are still evaluated according to the traditional efficacy paradigm focusing on the success in treating exacerbations and flares. Instead, the future approaches in drug development and assessment should rather concentrate on the long-term control of these diseases and consider their potential as disease-modifying strategies in the era of precision medicine. To reach this goal, a number of unsolved issues have to be addressed and consensually accepted by the stakeholders in this field. Thus, a successful and rapid development of new treatments requests a paradigm shift and a new way of thinking in the mind of physicians, pharmaceutical industry, regulators, and HTAs. This seems mandatory in order to optimize drug development and to facilitate the accessibility of new therapies to the growing population of patients suffering from atopic conditions on a global level.

IgE-associated allergic disorders: recent advances in etiology, diagnosis, and treatment

IgE-associated allergic diseases belong to the most common inflammatory conditions. Their clinical manifestation ranges from mild symptoms to life-threatening episodes. Often patients experience a reduction in physical and psychologic well-being and suffer from a decreased quality of life due to disease activity. The continuously rising number of people that are affected by an allergic condition indicates an urgent need for better diagnostics and more efficient treatment options. Recent progress in the understanding of pathophysiologic mechanisms underlying IgE-associated allergic disorders has led to the identification of novel therapeutic targets and the development of drug candidates that are currently under evaluation. In this review, we highlight studies and clinical trials, which have helped to gain further insight in the etiology of IgE-associated allergic conditions as well as advances in the development of diagnostic tools and therapeutic approaches recently published in Allergy (European Journal of Allergy and Clinical Immunology).

Targeting the T Helper 2 Inflammatory Axis in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that affects up to 25% of children and 10% of adults. The skin of patients with moderate to severe AD is characterized by significant barrier disruption and T helper 2 (Th2)-driven inflammation, which are thought to play a significant role in the pathogenesis of AD. Current management of AD is aimed at suppressing the inflammatory response and restoring the barrier function of the skin, reducing exacerbations, and preventing secondary skin infections. Combinations of treatment strategies are used to alleviate the symptoms of the disease; however, resolution is often temporary, and long-term usage of some of the medications for AD can be associated with significant side effects. Antibody therapies previously approved for other inflammatory diseases have been evaluated in patients with AD. Unfortunately, they have often failed to result in significant clinical improvement. Monoclonal antibodies and novel small molecules currently in development may provide more consistent benefit to patients with AD by specifically targeting the immune and molecular pathways important for the pathogenesis of AD. Here we review the state-of-the-art therapeutics targeting the Th2 axis in AD.

Economic evidence for the prevention and treatment of atopic eczema: a protocol for a systematic review

BACKGROUND

Eczema, synonymous with atopic eczema or atopic dermatitis, is a chronic skin disease that has a similar impact on health-related quality of life as other chronic diseases. The proposed research aims to provide a comprehensive systematic assessment of the economic evidence base available to inform economic modelling and decision making on interventions to prevent and treat eczema at any stage of the life course. Whilst the Global Resource of Eczema Trials (GREAT) database collects together the effectiveness evidence for eczema, there is currently no such systematic resource on the economics of eczema. It is important to gain an overview of the current state of the art of economic methods in the field of eczema in order to strengthen the economic evidence base further.

METHODS/DESIGN

The proposed study is a systematic review of the economic evidence surrounding interventions for the prevention and treatment of eczema. Relevant search terms will be used to search MEDLINE, EMBASE, Database of Abstracts of Reviews of Effects, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, National Health Service (NHS) Economic Evaluation Database, Health Technology Assessment, Cumulative Index to Nursing and Allied Health Literature, EconLit, Scopus, Cost-Effectiveness Analysis Registry and Web of Science in order to identify relevant evidence. To be eligible for inclusion studies will be primary empirical studies evaluating the cost, utility or full economic evaluation of interventions for preventing or treating eczema. Two reviewers will independently assess studies for eligibility and perform data abstraction. Evidence tables will be produced presenting details of study characteristics, costing methods, outcome methods and quality assessment. The methodological quality of studies will be assessed using accepted checklists.

DISCUSSION

The systematic review is being undertaken to identify the type of economic evidence available, summarise the results of the available economic evidence and critically appraise the quality of economic evidence currently available to inform future economic modelling and resource allocation decisions about interventions to prevent or treat eczema. We aim to use the review to offer guidance about how to gather economic evidence in studies of eczema and/or what further research is necessary in order to inform this.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015024633.

The adaptive immune system in atopic dermatitis and implications on therapy

In atopic dermatitis (AD), the skin inflammation is believed to occur due to a misdirected immune reaction against harmless antigens on the one hand, and to a disturbed skin barrier on the other. In recent years, vast efforts have been made to investigate the relevance and details of the immune response to allergens. Clinically, it was demonstrated for the first time that aeroallergen exposure leads to worsening of AD symptoms. An overexpression of Th2 cytokines has been observed in acute and subacute lesions of AD. The clinical impact of the key Th2 cytokines IL-4 and IL-13 on atopic dermatitis has recently been shown in clinical studies with dupilumab, a monoclonal antibody which blocks the IL-4/IL-13 receptor. In vitro data indicate, however, that the T cell response is not solely Th2-polarized but may lead to heterogeneous cytokine production involving IFN-γ and IL-17 in an allergen-dependent manner. Classical thymus-derived Foxp3 T cells have interestingly been detected in elevated numbers in the circulation of AD patients. Therapeutic approaches with allergen specific immunotherapy aim to induce regulatory T cells of the Tr1 type. The strikingly altered microbiome of AD skin with diminished diversity of bacteria on lesional skin but increases of S. aureus colonization and the sensitization against microbial allergens and homologue self-proteins deserve special attention. For the treatment of itch symptoms, which still represent a challenge in daily practice, promising data have been published on the relevance of the H(histamine)4-receptor and on mediators such as IL-31, TSLP.

Killing of Staphylococcus aureus via Magnetic Hyperthermia Mediated by Magnetotactic Bacteria

Staphylococcus aureus is a common hospital and household pathogen. Given the emergence of antibiotic-resistant derivatives of this pathogen resulting from the use of antibiotics as general treatment, development of alternative therapeutic strategies is urgently needed. Here, we assess the feasibility of killing S. aureus cells in vitro and in vivo through magnetic hyperthermia mediated by magnetotactic bacteria that possess magnetic nanocrystals and demonstrate magnetically steered swimming. The S. aureus suspension was added to magnetotactic MO-1 bacteria either directly or after coating with anti-MO-1 polyclonal antibodies. The suspensions were then subjected to an alternating magnetic field (AMF) for 1 h. S. aureus viability was subsequently assessed through conventional plate counting and flow cytometry. We found that approximately 30% of the S. aureus cells mixed with uncoated MO-1 cells were killed after AMF treatment. Moreover, attachment between the magnetotactic bacteria and S. aureus increased the killing efficiency of hyperthermia to more than 50%. Using mouse models, we demonstrated that magnetic hyperthermia mediated by antibody-coated magnetotactic MO-1 bacteria significantly improved wound healing. These results collectively demonstrated the effective eradication of S. aureus both in vitro and in vivo, indicating the potential of magnetotactic bacterium-mediated magnetic hyperthermia as a treatment for S. aureus-induced skin or wound infections.

Exaggerated IDO1 expression and activity in Langerhans cells from patients with atopic dermatitis upon viral stimulation: a potential predictive biomarker for high risk of Eczema herpeticum

BACKGROUND

Atopic dermatitis (AD) is a heterogenous and highly complex disease characterized by an increased microbial colonization. For unknown reasons, a subgroup of patients with AD develops Eczema herpeticum (EH), a severe viral complication due to spreading of herpes simplex virus (HSV). Indoleamine 2,3-dioxygenase (IDO1) is a tryptophan (Trp)-catabolizing enzyme which is assumed to be instrumental in the antibacterial and antiviral defence mechanisms.

METHODS

Comparative investigation of the IDO1 expression and activity in freshly isolated monocytes, plasmacytoid DC (pDC) and in vitro-generated Langerhans cells (LC) obtained from AD patients with HSV infections and EH and nonatopic controls.

RESULTS

We demonstrate an increase in Trp degradation in the serum of patients during acute EH episodes. Circulating pDC from patients with history of EH display an increased IDO1 expression. An increased Trp degradation is detected in the supernatants of circulating monocytes from AD patients with acute EH. Mature LC from AD patients with history of EH and with acute EH display an increased IDO1 expression and activity, respectively. In LC from patients with history of EH, viral signals induce an exaggerated IDO1 expression and activity.

CONCLUSION

IDO1 expression and activity in LC seem to be involved in the pathophysiology of EH in AD and could represent a predictive biomarker for patients with risk to develop EH and other viral complications.

Barrier function and microbiotic dysbiosis in atopic dermatitis

Atopic dermatitis (AD) or atopic eczema is the common inflammatory skin disorder, the prevalence of which has considerably increased during the last 30 years. It affects 15%-30% of children and 2%-10% of adults. AD characteristically alternates between periods of exacerbation or flares and periods of remission, which may be therapeutically induced or spontaneous. Current knowledge about AD includes abnormalities of the skin barrier (physical and chemical), the immune barrier, and more recently, the microbial barrier or microbiota. There is growing evidence for a tight relationship between them. To obtain satisfactory control of this condition, the clinical strategy to manage AD involves prescribing both anti-inflammatory medications and dermocosmetic products. The role of the physician is therefore to advise the patient with regard to hygiene measures aimed to help to improve these three barriers or to prevent any further deterioration.