Association of serum interleukin-18 and other biomarkers with disease severity in adults with atopic dermatitis

Management of Atopic Hand Dermatitis

Atopic hand dermatitis (AHD), a manifestation of atopic dermatitis, can have a profound negative effect on a patient's disease-related quality of life due to its visibility, chronic nature, and overall discomfort that it causes. AHD differs from other forms of chronic hand eczema due to its likely distinct, complex pathogenesis, which is a combination of environmental triggers, genetic predisposition, and immune dysfunction. A proper diagnosis of AHD is made through clinical evaluation and the ability to establish subtle clinical differences between AHD and other conditions. Diagnosis is the first step to a treatment plan that diverges from a one-size-fits-all approach.

Atopic dermatitis and food allergy: More than sensitization

The increased risk of food allergy in infants with atopic dermatitis (AD) has long been recognized; an epidemiologic phenomenon termed "the atopic march." Current literature supports the hypothesis that food antigen exposure through the disrupted skin barrier in AD leads to food antigen-specific immunoglobulin E production and food sensitization. However, there is growing evidence that inflammation in the skin drives intestinal remodeling via circulating inflammatory signals, microbiome alterations, metabolites, and the nervous system. We explore how this skin-gut axis helps to explain the link between AD and food allergy beyond sensitization.

A Narrative Review of the IL-18 and IL-37 Implications in the Pathogenesis of Atopic Dermatitis and Psoriasis: Prospective Treatment Targets

Atopic dermatitis and psoriasis are prevalent inflammatory skin conditions that significantly impact the quality of life of patients, with diverse treatment options available. Despite advances in understanding their underlying mechanisms, recent research highlights the significance of interleukins IL-18 and IL-37, in Th1, Th2, and Th17 inflammatory responses, closely associated with the pathogenesis of psoriasis and atopic dermatitis. Hence, IL-18 and IL-37 could potentially become therapeutic targets. This narrative review synthesizes knowledge on these interleukins, their roles in atopic dermatitis and psoriasis, and emerging treatment strategies. Findings of a literature search up to 30 May 2024, underscore a research gap in IL-37-targeted therapies. Conversely, IL-18-focused treatments have demonstrated promise in adult-onset Still's Disease, warranting further exploration for their potential efficacy in psoriasis and atopic dermatitis.

IL-18BP Therapy Ameliorates Reproductive and Metabolic Phenotypes in a PCOS Mouse Model by Relieving Inflammation, Fibrosis and Endoplasmic Reticulum Stress

There is a chronic inflammation in PCOS patients, which is correlated with the pathogenesis of PCOS. IL-18 and IL-18BP are related with some inflammatory diseases, while less explored in PCOS. Whether IL-18BP could be a potential drug of PCOS remains unknown.IL-18 and testosterone levels were evaluated in serum of 10 non-PCOS control patients and 20 PCOS patients. Female C57/BL6 mice were gavaged with letrozole to induce PCOS mouse model and IL-18 level was evaluated in the serum of PCOS mouse model, and IL-18 is intraperitoneally injected in female mice, IL-18BP is intraperitoneally injected in the PCOS mice models. Then the body weights, estrous cycles, reproductive hormones and morphology of ovaries were analyzed. The level of ovarian chronic inflammation, fibrosis and endoplasmic reticulum (ER) stress are evaluated.IL-18 levels are increased in the serum of PCOS patients and PCOS mice models respectively. The serum DHEAS, iWAT weight and adipocyte size were increased in IL-18 group compared to the control group (P < 0.05). In the PCOS mouse model treated with IL-18BP, the body weight and serum LH/FSH ratio was decreased compared to the PCOS group (P < 0.05). The expression levels of inflammatory factors and fibrosis-related genes, the expression level of endoplasmic reticulum stress-related genes, and the ROS positive area of ovarian tissue was decreased (P < 0.05).IL-18 is involved in inducing PCOS phenotypes, while IL-18BP relieves PCOS phenotypes by alleviating ovarian chronic inflammation, fibrosis and ER stress in PCOS mice.

Interleukin-1 family cytokines at the crossroads of microbiome regulation in barrier health and disease

Recent advances in understanding how the microbiome can influence both the physiology and the pathogenesis of disease in humans have highlighted the importance of gaining a deeper insight into the complexities of the host-microbial dialogue. In tandem with this progress, has been a greater understanding of the biological pathways which regulate both homeostasis and inflammation at barrier tissue sites, such as the skin and the gut. In this regard, the Interleukin-1 family of cytokines, which can be segregated into IL-1, IL-18 and IL-36 subfamilies, have emerged as important custodians of barrier health and immunity. With established roles as orchestrators of various inflammatory diseases in both the skin and intestine, it is now becoming clear that IL-1 family cytokine activity is not only directly influenced by external microbes, but can also play important roles in shaping the composition of the microbiome at barrier sites. This review explores the current knowledge surrounding the evidence that places these cytokines as key mediators at the interface between the microbiome and human health and disease at the skin and intestinal barrier tissues.

The ability of biomarkers to assess the severity of atopic dermatitis

Background

To develop precision medicine for atopic dermatitis (AD), it is critical to establish relevant biomarkers. However, the characteristics of various biomarkers have not been fully understood. We previously carried out the Biomarkers to Predict Clinical Improvement of AD in Patients Treated with Dupilumab (B-PAD) study, a comprehensive nationwide study in Japan, to explore biomarkers for AD.

Objective

The aim of this study is to find biomarkers associated with objective and subjective clinical findings in patients with moderate-to-severe AD based on the B-PAD study and to identify biomarkers sensitive enough to assess the severity of AD.

Methods

We performed the B-PAD study as a consortium composed of 19 medical facilities in Japan, enrolling 110 patients with moderate-to-severe AD. We evaluated the Eczema Area and Severity Index (EASI) for objective assessment as well as the Patient-Oriented Eczema Measure (POEM) and a numeric rating scale for pruritus (pruritis-NRS) for subjective assessment, measuring 19 biomarkers at baseline.

Results

We found that 12, 6, and 7 biomarkers showed significant and positive associations with the EASI, POEM, and pruritis-NRS, respectively. Most of the biomarkers associated with either the POEM or the pruritis-NRS were included among the biomarkers associated with EASI. Of the biomarkers examined, CCL26/eotaxin-3 and SCCA2 were the most capable of assessing severity for EASI, as shown by the 2 kinds of receiver operating characteristic analyses, respectively, whereas lactate dehydrogenase was the best for both the POEM and pruritis-NRS, again using the 2 analyses.

Conclusion

We found biomarkers associated with the EASI, POEM, and pruritis-NRS, respectively, based on the B-PAD study. Moreover, we identified CCL26/eotaxin-3 and/or SCCA2 as the biomarkers having the greatest ability to assess severity in the EASI; lactate dehydrogenase did the same for the POEM and pruritis-NRS. These findings will be useful in treating patients with moderate-to-severe AD.

Albumin-binding recombinant human IL-18BP ameliorates macrophage activation syndrome and atopic dermatitis via direct IL-18 inactivation

Given the clinical success of cytokine blockade in managing diverse inflammatory human conditions, this approach could be exploited for numerous refractory or uncontrolled inflammatory conditions by identifying novel targets for functional blockade. Interleukin (IL)-18, a pro-inflammatory cytokine, is relatively underestimated as a therapeutic target, despite accumulated evidence indicating the unique roles of IL-18 in acute and chronic inflammatory conditions, such as macrophage activation syndrome. Herein, we designed a new form of IL-18 blockade, i.e., APB-R3, a long-acting recombinant human IL-18BP linked to human albumin-binding Fab fragment, SL335, for extending half-life. We then explored the pharmacokinetics and pharmacodynamics of APB-R3. In addition to an extended serum half-life, APB-R3 alleviates liver inflammation and splenomegaly in a model of the macrophage activation syndrome induced in IL-18BP knockout mice. Moreover, APB-R3 substantially controlled skin inflammation in a model of atopic dermatitis. Thus, we report APB-R3 as a new potent IL-18 blocking agent that could be applied to treat IL-18-mediated inflammatory diseases.

Associations of serum keratin 1 with thyroid function and immunity in Graves' disease

BACKGROUND

Autoimmune thyroid disease (AITD) can cause enormous health burdens; however, trustworthy biomarkers in identifying the onset and progression of AITD are limited. In this study, we attempted to discover new potential serum biomarkers to discriminate AITD using mass spectrometry (MS).

METHODS

In the biomarker study cohort, 20 patients with Graves' disease (GD), 20 patients with Hashimoto's thyroiditis (HT), and 20 healthy controls were enrolled for a liquid chromatographic-tandem MS assessment. A novel biomarker, keratin 1 (KRT1), was selected for further evaluation in the validation cohort, including 125 patients with GD, 34 patients with HT, and 77 controls. Relationships of serum KRT1 with AITD-related immunomodulatory cytokines were also analyzed using enzyme-linked immunosorbent assays (ELISAs).

RESULTS

In the MS analysis, KRT1 was the single marker overexpressed in GD, while it was underexpressed in HT. In the ELISA analysis of the validation cohort, KRT1 was consistently upregulated in GD, while it was not downregulated in HT. There were significant associations of KRT1 levels with thyroid function in GD, AITD, and overall subjects. Additionally, a significant association of KRT1 levels with thyroid-stimulating hormone receptor antibody (TSHRAb) levels was observed. Moreover, there were significant associations of KRT1 with osteopontin (OPN) and B-cell activating factor (BAFF) levels in GD.

CONCLUSIONS

Serum KRT1 levels were upregulated in GD and were associated with thyroid function and TSHRAb levels. Moreover, KRT1 was correlated with the BAFF and OPN levels in GD patients. Further molecular-based research to elucidate the role of KRT1 in the pathogenesis of AITD is needed.

Efficacy and Safety of Dupilumab Maintained in Adults ≥ 60 Years of Age with Moderate-to-Severe Atopic Dermatitis: Analysis of Pooled Data from Four Randomized Clinical Trials

BACKGROUND

Adults aged ≥ 60 years are often underrepresented in atopic dermatitis (AD) clinical trials; age-related comorbidities may impact treatment efficacy and safety.

OBJECTIVE

The aim was to report dupilumab efficacy and safety in patients aged ≥ 60 years with moderate-to-severe AD.

METHODS

Data were pooled from four randomized, placebo-controlled dupilumab trials of patients with moderate-to-severe AD (LIBERTY AD SOLO 1 and 2, LIBERTY AD CAFÉ, and LIBERTY AD CHRONOS) and stratified by age (< 60 [N = 2261] and ≥ 60 [N = 183] years). Patients received dupilumab 300 mg every week (qw) or every 2 weeks (q2w), or placebo with/without topical corticosteroids. Post hoc efficacy at week 16 was examined using broad categorical and continuous assessments of skin lesions, symptoms, biomarkers, and quality of life. Safety was also assessed.

RESULTS

In the ≥ 60-year-old group at week 16, a greater proportion of dupilumab-treated patients achieved an Investigator's Global Assessment score of 0/1 (q2w: 44.4%; qw: 39.7%) and 75% improvement in Eczema Area and Severity Index (63.0%; 61.6%) versus placebo (7.1% and 14.3%, respectively; P < 0.0001). Type 2 inflammation biomarkers (immunoglobulin E and thymus and activation-regulated chemokine) were also significantly reduced in dupilumab- versus placebo-treated patients (P < 0.01). Results were similar in the < 60-year-old group. The exposure-adjusted incidences of adverse events in dupilumab-treated patients were generally similar to those receiving placebo, with numerically fewer treatment-emergent adverse events in the dupilumab-treated ≥ 60-year-old group versus placebo.

LIMITATIONS

There were fewer patients in the ≥ 60-year-old group; post hoc analyses.

CONCLUSION

Dupilumab improved AD signs and symptoms in patients aged ≥ 60 years; results were comparable to those in patients aged < 60 years. Safety was consistent with the known dupilumab safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02277743, NCT02277769, NCT02755649, NCT02260986. Does dupilumab benefit adults aged 60 years and older with moderate-to-severe atopic dermatitis?(MP4 20,787 KB).

Blood-Based Biomarkers for Eosinophilic Esophagitis and Concomitant Atopic Diseases: A Look into the Potential of Extracellular Vesicles

Eosinophilic esophagitis (EoE) is a chronic, Th2-inflammatory disease of the esophagus that can severely affect food intake. Currently, diagnosis and assessing response to treatment of EoE is highly invasive and requires endoscopy with esophageal biopsies. Finding non-invasive and accurate biomarkers is important for improving patient well-being. Unfortunately, EoE is usually accompanied by other atopies, which make it difficult to identify specific biomarkers. Providing an update of circulating EoE biomarkers and concomitant atopies is therefore timely. This review summarizes the current knowledge in EoE blood biomarkers and two of its most common comorbidities, bronchial asthma (BA) and atopic dermatitis (AD), focusing on dysregulated proteins, metabolites, and RNAs. It also revises the current knowledge on extracellular vesicles (EVs) as non-invasive biomarkers for BA and AD, and concludes with the potential use of EVs as biomarkers in EoE.

Interleukin-18 and IL-18BP in inflammatory dermatological diseases

Interleukin (IL)-18, an interferon-γ inducer, belongs to the IL-1 family of pleiotropic pro-inflammatory factors, and IL-18 binding protein (IL-18BP) is a native antagonist of IL-18 in vivo, regulating its activity. Moreover, IL-18 exerts an influential function in host innate and adaptive immunity, and IL-18BP has elevated levels of interferon-γ in diverse cells, suggesting that IL-18BP is a negative feedback inhibitor of IL-18-mediated immunity. Similar to IL-1β, the IL-18 cytokine is produced as an indolent precursor that requires further processing into an active cytokine by caspase-1 and mediating downstream signaling pathways through MyD88. IL-18 has been implicated to play a role in psoriasis, atopic dermatitis, rosacea, and bullous pemphigoid in human inflammatory skin diseases. Currently, IL-18BP is less explored in treating inflammatory skin diseases, while IL-18BP is being tested in clinical trials for other diseases. Thereby, IL-18BP is a prospective therapeutic target.

Laboratory Safety from a Randomized 16-Week Phase III Study of Dupilumab in Children Aged 6 Months to 5 Years with Moderate-to-Severe Atopic Dermatitis

BACKGROUND AND OBJECTIVE

Previous studies of dupilumab for the treatment of moderate-to-severe atopic dermatitis in adults and adolescents, and severe atopic dermatitis in children aged 6 to < 12 years demonstrate no clinically important changes in laboratory parameters. The objective of this study was to assess laboratory outcomes in children aged 6 months to < 6 years with moderate-to-severe atopic dermatitis treated with dupilumab.

METHODS

In this randomized, placebo-controlled, phase III trial of dupilumab, 161 children aged 6 months to < 6 years with moderate-to-severe atopic dermatitis were enrolled from 31 sites in Europe and North America and randomized 1:1 to receive subcutaneous placebo or dupilumab (5 kg to < 15 kg: 200 mg; 15 kg to < 30 kg: 300 mg) every 4 weeks plus topical corticosteroids for 16 weeks. Hematology, serum chemistry, and urinalysis assessments were analyzed on blood and urine samples collected at screening and weeks 4 and 16; descriptive statistics are provided.

RESULTS

No clinically meaningful changes in laboratory parameters were observed. While two cases of eosinophilia and one case each of neutropenia and leukocytosis were reported as treatment-emergent adverse events in the dupilumab plus topical corticosteroids group, these events were not associated with clinical symptoms and did not lead to treatment discontinuation or study withdrawal.

CONCLUSIONS

These results suggest that routine laboratory monitoring of children aged 6 months to < 6 years treated with dupilumab plus topical corticosteroids is not required. Limitations of this study include short study duration, and exclusion of patients with abnormalities in laboratory test results at screening.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT03346434, part B.

Isosorbide Fatty Acid Diesters Have Synergistic Anti-Inflammatory Effects in Cytokine-Induced Tissue Culture Models of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic disease in which epidermal barrier disruption triggers Th2-mediated eruption of eczematous lesions. Topical emollients are a cornerstone of chronic management. This study evaluated efficacy of two plant-derived oil derivatives, isosorbide di-(linoleate/oleate) (IDL) and isosorbide dicaprylate (IDC), using AD-like tissue culture models. Treatment of reconstituted human epidermis with cytokine cocktail (IL-4 + IL-13 + TNF-α + IL-31) compromised the epidermal barrier, but this was prevented by co-treatment with IDL and IDC. Cytokine stimulation also dysregulated expression of keratinocyte (KC) differentiation genes whereas treatment with IDC or IDL + IDC up-regulated genes associated with early (but not late) KC differentiation. Although neither IDL nor IDC inhibited Th2 cytokine responses, both compounds repressed TNF-α-induced genes and IDL + IDC led to synergistic down-regulation of inflammatory (IL1B, ITGA5) and neurogenic pruritus (TRPA1) mediators. Treatment of cytokine-stimulated skin explants with IDC decreased lactate dehydrogenase (LDH) secretion by more than 50% (more than observed with cyclosporine) and in vitro LDH activity was inhibited by IDL and IDC. These results demonstrate anti-inflammatory mechanisms of isosorbide fatty acid diesters in AD-like skin models. Our findings highlight the multifunctional potential of plant oil derivatives as topical ingredients and support studies of IDL and IDC as therapeutic candidates.

Efficacy and Safety of Upadacitinib for Management of Moderate-to-Severe Atopic Dermatitis: An Evidence-Based Review

Atopic dermatitis (AD) is a common skin condition characterized by inflammation that presents with erythematous and pruritic skin. Its chronic relapse-remitting nature has a significant impact on the quality of life, and often requires ongoing management. Given the limited treatments available for AD, there remains a large need for effective and safe alternative therapies for long-term use. Janus kinase (JAK) inhibitors are a new class of agents that target the JAK-STAT pathway, which plays an important role in the production of proinflammatory cytokines involved in AD pathogenesis. Phase II and III clinical trials revealed that JAK inhibitors, such as upadacitinib, are effective and well-tolerated agents for the treatment of moderate-to-severe AD. As a result, upadacitinib was approved for use in patients with moderate-to-severe AD by the European Medicines Agency (2021), Health Canada (2021) and the FDA (2022) in the last year. It is important for dermatologists to be aware of the clinical evidence to continue incorporating the use of upadacitinib into the treatment algorithm for AD, which will ultimately lead to improved patient outcomes. Therefore, this review is an up-to-date summary of the clinical data available on the efficacy and safety of upadacitinib treatment for AD.

Release of Cervical Muscle Tension Improves Psychological Stress and Symptoms of Moderate-to-Severe Atopic Dermatitis: a Case Series with 20 Patients

Introduction

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease that is triggered by intense pruritus, impaired skin barrier function, and immune responses to allergenic substances. Break-through therapies for AD include molecular-targeted drugs and the effective management of severe symptoms of AD. However, patients with clinical improvements may continue scratching owing to the influence of psychological stress, which might lead to quick relapses of stressors and subsequent intensive scratching. New drugs may be ineffective because of such scratching behavior caused by stressors. Therefore, it may be useful to consider adjunctive treatment options that focus on external stressors as triggers of deterioration of AD. We hypothesized that improvement of psychological stress by relieving cervical muscle tension would reduce pruritus and atopic symptoms.

Methods

Overall, 21 patients with moderate-to-severe AD were treated to relieve cervical muscular tension using Spineliner SA201, which assists in osteopathic manipulative treatment. We assessed the subjective and objective symptoms of AD, cervical muscle tension, which was evaluated using cervical range of motion (ROM), and psychological burden. Only moisturizers were applied topically during the study period, and no topical corticosteroid therapy was used.

Results

Twenty patients who completed the treatment demonstrated improvement in the symptoms of AD: changes on the visual analog scale (VAS) for pruritus were −44.2%, Eczema Area and Severity Index (EASI) was −67.9%, thymus and activation-regulated chemokine (TARC) was −56.2%, Hospital Anxiety and Depression Scale (HADS) was −27.2%, sleep disturbance was −49.7%, and Dermatology Life Quality Index (DLQI) was −46.7%. Additionally, the cervical muscle tension improved significantly: changes in cervical ROM were 14.7%.

Conclusions

Release of cervical muscle tension may improve psychological stress and have an effect on moderate-to-severe AD.

Atopic dermatitis is a chronic relapsing inflammatory skin disease triggered by intense pruritus, impaired skin barrier function, and immune responses. Standard dermatological therapies for patients with atopic dermatitis include topical glucocorticoid treatments. In some cases, scratching and inflammation could not be adequately controlled, a relapse could not be prevented after remission, and their efficacy is limited. Break-through therapies for atopic dermatitis include new molecular biological drugs, which have demonstrated significantly improved and effective management of severe atopic symptoms. However, patients with clinical improvements may continue scratching owing to psychological stress, which might lead to quick relapses of stressors and subsequent intensive scratching. New drugs may be ineffective owing to such scratching behavior caused by stressors. Therefore, it may be useful to consider adjunctive treatment options focusing on external stressors as triggers for worsening atopic dermatitis. We hypothesized that improvement of psychological stress by relieving cervical muscle tension would reduce pruritus and atopic symptoms. Overall, 21 patients with moderate-to-severe atopic dermatitis were treated to relieve cervical muscular tension using Spineliner SA201, which assists in osteopathic manipulative treatment. We assessed the subjective and objective atopic symptoms, cervical muscle tension, and psychological burden. Only moisturizers were applied topically during the study period, and no topical corticosteroid therapy was used. Twenty patients completed the treatment, atopic symptoms improved significantly, cervical muscular tension improved, and the psychological burden decreased with the treatment. Release of cervical muscle tension may improve psychological stress and affect moderate-to-severe atopic dermatitis.

Atopic Dermatitis: Striving for Reliable Biomarkers

Atopic dermatitis (AD) is a highly heterogeneous inflammatory disease regarding both its pathophysiology and clinical manifestations. However, it is treated according to the “one-size-fits-all” approach, which may restrict response to treatment. Thus, there is an unmet need for the stratification of patients with AD into distinct endotypes and clinical phenotypes based on biomarkers that will contribute to the development of precision medicine in AD. The development of reliable biomarkers that may distinguish which patients with AD are most likely to benefit from specific targeted therapies is a complex procedure and to date none of the identified candidate biomarkers for AD has been validated for use in routine clinical practice. Reliable biomarkers in AD are expected to improve diagnosis, evaluate disease severity, predict the course of disease, the development of comorbidities, or the therapeutic response, resulting in effective and personalized treatment of AD. Among the studied AD potential biomarkers, thymus and activation-regulated chemokine/C-C motif ligand 17 (TARC/CCL17) has the greatest evidence-based support for becoming a reliable biomarker in AD correlated with disease severity in both children and adults. In this review, we present the most prominent candidate biomarkers in AD and their suggested use.

Altered plasma cytokines in dogs with atopic dermatitis

BACKGROUND

Canine (Canis lupus familiaris) atopic dermatitis (AD) shares similar clinical signs to human AD. The abnormal immune response of AD is orchestrated by T lymphocytes, and may include variable involvement of cytokines, regulatory T (Treg) cells, eosinophils, mast cells and other immune components. Helper T (Th)2 cytokines often predominate initially, followed by Th1 cytokines in more chronic phases.

HYPOTHESIS/OBJECTIVES

Pro-inflammatory and Treg cytokines have been shown to play a role in human AD, yet their importance is not clear in canine AD. Hence, this study aimed to measure the concentrations of cytokines/chemokines not traditionally associated with Th1/Th2 response.

ANIMALS

Canine AD patients (n = 27), compared to control dogs (n = 11).

METHODS AND MATERIALS

A total of 19 plasma cytokines were assayed using canine specific multiplex immuno-assays.

RESULTS

The plasma concentrations of CXC Motif Chemokine Ligand 8 (CXCL8), interleukin (IL)-7 and IL-15 cytokines were elevated in canine AD patients, compared to control dogs. In addition, stem-cell factor (SCF) concentrations were reduced in the plasma of canine AD patients compared to control dogs. Distinct cytokine profiles were found in dogs belonging to the Staffordshire breeds, a group with increased risk of AD. In particular, granulocyte-macrophage colony-stimulating factor (GM-CSF) had significantly elevated concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Some of the plasma cytokine alterations in canine AD described here, particularly of IL-7, have not been reported previously. Monitoring these distinctive cytokine alterations could be useful for diagnosis and monitoring of canine AD in dogs.

Characterisation of the serum cytokine profile in feline atopic skin syndrome

BACKGROUND

Feline atopic skin syndrome (FASS) is a pruritic and inflammatory skin disease commonly encountered in cats. Three previous reports evaluated cytokine immune activation in cats diagnosed with feline allergic dermatitis. However, no significant upregulations were observed in allergic cats compared to healthy controls.

HYPOTHESIS/OBJECTIVE

To evaluate differences in the serum cytokine profile of cats diagnosed with FASS compared to healthy cats, and correlate serum markers with the extent of FASS skin disease using clinical scoring systems.

ANIMALS

Thirteen client-owned FASS cats and 12 healthy control cats.

METHODS AND MATERIALS

Thirteen cytokine and chemokines from the serum of FASS cats and healthy controls were analysed using a commercially available feline-specific multiplex assay.

RESULTS

Patients with FASS had a significant increase in serum concentrations of interferon-gamma (IFN-γ), interleukin (IL)-2, IL-13 and IL-18. In addition, cytokine/chemokines involved in inflammation and chemotaxis [IL-8, C-C Motif Chemokine Ligand (CCL)5, CCL2 and CXCL12], as well as growth factors, stem cell factor and Fms-related tyrosine kinase 3 ligand (Flt3L), also were significantly elevated. A significant positive correlation (r = 0.64) between the serum levels of Flt3L and Scoring Feline Allergic Dermatitis (SCORFAD) score was observed.

CONCLUSIONS

These results demonstrate the activation of a broad array of immune secretory cytokines in the serum of cats with FASS, which are largely associated with a mixed Th1 and Th2 inflammatory response along with specific growth factors. Further larger-sample studies are needed to assess the modulation of serum biomarkers in FASS by pharmacological/therapeutic interventions.

Biomarkers in atopic dermatitis-a review on behalf of the International Eczema Council

Atopic dermatitis (AD) is a common yet complex skin disease, posing a therapeutic challenge with increasingly recognized different phenotypes among variable patient populations. Because therapeutic response may vary on the basis of heterogeneous clinical and molecular phenotypes, a shift toward precision medicine approaches may improve AD management. Herein, we will consider biomarkers as potential instruments in the toolbox of precision medicine in AD and will review the process of biomarker development and validation, the opinion of AD experts on the use of biomarkers, types of biomarkers, encompassing biomarkers that may improve AD diagnosis, biomarkers reflecting disease severity, and those potentially predicting AD development, concomitant atopic diseases, or therapeutic response, and current practice of biomarkers in AD. We found that chemokine C-C motif ligand 17/thymus and activation-regulated chemokine, a chemoattractant of TH2 cells, has currently the greatest evidence for robust correlation with AD clinical severity, at both baseline and during therapy, by using the recommendations, assessment, development, and evaluation approach. Although the potential of biomarkers in AD is yet to be fully elucidated, due to the complexity of the disease, a comprehensive approach taking into account both clinical and reliable, AD-specific biomarker evaluations would further facilitate AD research and improve patient management.

Effect of Dupilumab on Laboratory Parameters in Adolescents with Atopic Dermatitis: Results from a Randomized, Placebo-Controlled, Phase 3 Clinical Trial

Background

Laboratory testing is typically required for patients with atopic dermatitis (AD) treated with systemic immunosuppressants. A previous analysis of laboratory outcomes in randomized, double-blinded, placebo-controlled clinical trials of dupilumab in adults with moderate-to-severe AD found no clinically important changes in hematologic, serum chemistry, and urinalysis parameters, supporting the use of dupilumab without routine laboratory monitoring.

Objective

The aim was to assess laboratory results in adolescents with moderate-to-severe AD treated with dupilumab in a phase 3, randomized, double-blind, placebo-controlled trial.

Methods

Adolescents aged ≥ 12 to < 18 years with moderate-to-severe AD were randomized 1:1:1 to subcutaneous dupilumab 200/300 mg every 2 weeks (q2w) (200 mg for patients < 60 kg at baseline; 300 mg for patients ≥ 60 kg at baseline); dupilumab 300 mg every 4 weeks (q4w); or placebo for 16 weeks. Laboratory evaluations included hematology, serum chemistry, and urinalysis parameters.

Results

Of 251 patients enrolled in the study, 250 received treatment and were included in the analysis. 4.7%, 2.4%, and 4.8% of patients receiving placebo, dupilumab 200/300 mg q2w, and dupilumab 300 mg q4w, respectively, had laboratory abnormalities reported as treatment-emergent adverse events, none of which prompted discontinuation of study treatment or study withdrawal. Mean eosinophil counts were elevated at baseline in all treatment groups. Patients in both dupilumab regimens, but not the placebo group, showed mild transient increases in mean eosinophil counts above baseline that returned to near-baseline values by week 16. Mean levels of lactate dehydrogenase trended towards the upper limit of normal at baseline and decreased with treatment; greater decreases were seen in dupilumab-treated patients than placebo-treated patients. There were no meaningful changes in other laboratory parameters, and none of the laboratory abnormalities were clinically significant.

Conclusion

No clinically meaningful changes in laboratory parameters were seen in adolescents, similar to that observed in adults. The findings of this study indicate no routine laboratory monitoring is required in this population prior to or during dupilumab treatment.

Trial Registration

ClinicalTrials.gov: NCT03054428.

Video Abstract

Laboratory safety of dupilumab for up to 3 years in adults with moderate-to-severe atopic dermatitis: results from an open-label extension study

BACKGROUND

Most systemic agents used for moderate-to-severe atopic dermatitis (AD) may lead to adverse events requiring routine laboratory monitoring, increasing patient burden and possibly decreasing treatment adherence.

OBJECTIVE

To evaluate clinical laboratory findings in adults with moderate-to-severe AD treated with dupilumab up to 3 years.

METHODS

LIBERTY AD OLE (NCT01949311) was a phase 3, multicenter, open-label extension study in adults with moderate-to-severe AD receiving dupilumab 300 mg weekly.

RESULTS

2,677 patients were treated up to 3 years. No clinically meaningful changes in mean hematology/serum chemistry parameters from baseline were observed. Few laboratory abnormalities were reported as treatment-emergent adverse events. Serious events included one event each of thrombocytopenia, hematuria, and hemolytic anemia, all unrelated to treatment. Abnormalities leading to treatment withdrawal included thrombocytopenia (one patient), increased hepatic enzymes (two patients), and blood creatine phosphokinase increased (one patient). No patients had Grade 3 anemia or Grade 3/4 thrombocytopenia; one patient had Grade 3 neutropenia (Week 100); two patients had Grade 3 eosinophilia (baseline visit); no eosinophil abnormalities were associated with clinically symptomatic events/permanent treatment discontinuation.

CONCLUSION

Dupilumab treatment of adults with moderate-to-severe AD up to 3 years showed no clinically meaningful changes in mean laboratory parameters, supporting continuous long-term use without laboratory monitoring.

CLINICALTRIALS.GOV IDENTIFIER

NCT01949311.

Immunological Roles of NLR in Allergic Diseases and Its Underlying Mechanisms

Our understanding on the immunological roles of pathogen recognition in innate immunity has vastly increased over the past 20 years. Nucleotide-binding oligomerization domain (NOD)-like receptors (NLR) are cytosolic pattern recognition receptors (PRR) that are responsible for sensing microbial motifs and endogenous damage signals in mammalian cytosol for immune surveillance and host defense. The accumulating discoveries on these NLR sensors in allergic diseases suggest that the pathogenesis of allergic diseases may not be confined to the adaptive immune response. Therapy targeting NLR in murine models also shields light on its potential in the treatment of allergies in man. In this review, we herein summarize the recent understanding of the role of NLR sensors and their molecular mechanisms involved in allergic inflammation, including atopic dermatitis and allergic asthma.

Interleukin-8 Levels in the Stratum Corneum as a Biomarker for Monitoring Therapeutic Effect in Atopic Dermatitis Patients

INTRODUCTION

The stratum corneum contains several growth factors and cytokines that are synthesized in keratinocytes. We previously reported that the amount of interleukin-8 in the stratum corneum (scIL-8) is related to the severity of local skin inflammation in atopic dermatitis (AD). However, it is unknown whether scIL-8 levels reflect pharmacologic responses to a therapeutic intervention in AD patients. Therefore, in this study, we aimed to investigate whether the improvement of dermatitis in AD is correlated with scIL-8 levels before and after topical corticosteroid treatment.

METHODS

Stratum corneum samples were collected from 22 AD patients using the noninvasive tape-stripping method before treatment, 2 weeks after topical treatment, and 4-6 weeks after treatment.

RESULTS

scIL-8 levels on the forearm reduced significantly from 790 ± 348 pg/mg before treatment to 163 ± 68 pg/mg 2 weeks after treatment and 100 ± 37 pg/mg 4-6 weeks after corticosteroid treatment. scIL-8 levels on the abdomen also reduced significantly from 902 ± 391 to 142 ± 38 pg/mg at the end of study. The reduction in scIL-8 levels was associated with the improvement in local skin severity in AD. We also found that scIL-8 levels, along with blood biomarker levels (serum thymus and activation-regulated chemokine, lactate dehydrogenase, and %eosinophil), decreased significantly after the treatment.

CONCLUSION

The scIL-8 concentration decreases with improvements in skin symptoms in AD patients after topical corticosteroid treatment; thus, it may be a suitable biomarker for monitoring therapeutic effects in AD patients.

Selective JAK1 Inhibitors for the Treatment of Atopic Dermatitis: Focus on Upadacitinib and Abrocitinib

Atopic dermatitis is a common, chronic, immune-mediated disease associated with several comorbidities. Elevated levels of T helper (Th)2, Th22, and also some Th1 and Th17 cytokines are found in atopic dermatitis skin lesions. Similar to psoriasis, there is a tendency towards increased use of more targeted therapies. However, there are still several unmet needs in the treatment of atopic dermatitis concerning long-term efficacy, tolerability, safety, route of administration, and cost. The increased knowledge of atopic dermatitis pathogenesis and the role of Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways has allowed the development of new compounds to inhibit this intracellular signaling pathway implicated in atopic dermatitis-related immune responses. Currently, JAK inhibitors are an important focus of therapeutic research for atopic dermatitis. Upadacitinib and abrocitinib are oral small molecules that inhibit the JAK/STAT pathway by selectively blocking JAK1. Data from phase II and III trials are encouraging, revealing that JAK1 inhibitors are effective and well-tolerated agents for moderate-to-severe atopic dermatitis. Selective JAK1 inhibitors may represent an important therapeutic option to be included in the treatment algorithm of atopic dermatitis, owing to oral administration and a favorable safety and tolerability profile. In this article, we review the current evidence on the efficacy and safety of oral selective JAK1 inhibitors for the treatment of atopic dermatitis.

Dupilumab treatment ameliorates clinical and hematological symptoms, including blood eosinophilia, in patients with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is an allergic disease that affects individuals of various ages. Recently, the IL-4/13 inhibitor dupilumab has gained regulatory approval for clinical use in AD patients. Dupilumab has been reported to reduce several markers of AD, including the serum levels of thymus and activation-regulated chemokine (TARC/CCL17), blood lactate dehydrogenase (LDH), and serum total immunoglobulin E (IgE).

METHODS

We retrospectively reviewed data from 40 AD patients who were treated with dupilumab. Eczema Area and Severity Index (EASI), Investigator's Global Assessment (IGA), body surface area (BSA) scores, TARC, LDH, total IgE, and eosinophil count in peripheral blood were assessed for a total of 32 weeks.

RESULTS

The EASI, IGA, and BSA scores improved significantly with treatment, indicating a reduction in AD severity. Serum TARC and LDH levels also significantly decreased with treatment. Serum IgE levels were unchanged at 2 weeks of treatment but decreased significantly between 4 and 32 weeks. The number of eosinophils in the peripheral blood decreased at 4, 16, and 32 weeks after treatment initiation.

CONCLUSIONS

Several studies have reported that serum TARC, LDH, and total IgE levels are reduced by dupilumab treatment. Our real-world data are the first to demonstrate a reduction in blood eosinophilia in patients who receive clinical treatment with dupilumab.

Serum canine thymus and activation-regulated chemokine (TARC/CCL17) concentrations correlate with disease severity and therapeutic responses in dogs with atopic dermatitis

Background

Thymus and activation‐regulated chemokine (TARC/CCL17) has been implicated in the pathogenesis of canine atopic dermatitis (cAD). Serum TARC concentrations are a reliable biomarker for human atopic dermatitis; however, their potential as a biomarker for cAD has not been investigated.

Hypothesis/Objectives

To investigate whether serum TARC concentrations correlate with disease severity and therapeutic responses for cAD.

Animals

Thirty‐nine dogs with cAD and 42 healthy dogs were recruited.

Methods and materials

Serum TARC concentrations in dogs with cAD and healthy dogs were measured by sandwich ELISA with anti‐canine TARC antibodies. The clinical severity of cAD was scored using the validated Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI‐04). Serum TARC concentrations were compared between dogs with cAD and healthy controls, and their relationship with CADESI‐04 was examined. Serum TARC concentrations also were measured in 20 dogs with cAD treated with prednisolone or oclacitinib for four weeks.

Results

Serum TARC concentrations were significantly higher in dogs with cAD than in healthy dogs (P < 0.001). In dogs with cAD, serum TARC concentrations correlated with CADESI‐04 scores (ρ = 0.457, P < 0.01). Furthermore, serum TARC concentrations significantly decreased in treated dogs with the attenuation of clinical signs (P < 0.001). Changes in serum TARC concentrations before and after treatment correlated with those in CADESI‐04 scores (ρ = 0.746, P < 0.001).

Conclusions and clinical relevance

Serum TARC concentrations have potential as a clinical and research tool for the objective evaluation of disease severity and therapeutic responses for cAD.

Efficacy and Safety of Dupilumab in Adolescents With Uncontrolled Moderate to Severe Atopic Dermatitis: A Phase 3 Randomized Clinical Trial

Importance

Adolescents with atopic dermatitis (AD) have high disease burden negatively affecting quality of life, with limited treatment options. The efficacy and safety of dupilumab, a monoclonal antibody, approved for treatment in adolescent patients with inadequately controlled AD, remain unknown in this patient population.

Objective

To assess the efficacy and safety of dupilumab monotherapy in adolescents with moderate to severe inadequately controlled AD.

Design, Setting, and Participants

A randomized, double-blind, parallel-group, phase 3 clinical trial was conducted at 45 US and Canadian centers between March 21, 2017, and June 5, 2018. A total of 251 adolescents with moderate to severe AD inadequately controlled by topical medications or for whom topical therapy was inadvisable were included.

Interventions

Patients were randomized (1:1:1; interactive-response system; stratified by severity and body weight) to 16-week treatment with dupilumab, 200 mg (n = 43; baseline weight <60 kg), or dupilumab, 300 mg (n = 39; baseline weight ≥60 kg), every 2 weeks; dupilumab, 300 mg, every 4 weeks (n = 84); or placebo (n = 85).

Main Outcomes and Measures

Proportion of patients with 75% or more improvement from baseline in Eczema Area and Severity Index (EASI-75) (scores range from 0 to 72, with higher scores indicating greater severity) and Investigator's Global Assessment (IGA) 0 or 1 on a 5-point scale (scores range from 0 to 4, with higher scores indicating greater severity) at week 16.

Results

A total of 251 patients were randomized (mean [SD] age, 14.5 [1.7] years; 148 [59.0%] male). Of 250 patients with data available on concurrent allergic conditions, most had comorbid type 2 diseases (asthma, 134 [53.6%]; food allergies, 60.8%; allergic rhinitis, 65.6%). A total of 240 patients (95.6%) completed the study. Dupilumab achieved both coprimary end points at week 16. The proportion of patients with EASI-75 improvement from baseline increased (every 2 weeks, 41.5%; every 4 weeks, 38.1%; placebo, 8.2%) with differences vs placebo of 33.2% (95% CI, 21.1%-45.4%) for every 2 weeks and 29.9% (95% CI, 17.9%-41.8%) for every 4 weeks (P < .001). Efficacy of the every-2-week regimen was generally superior to the every-4-week regimen. Patients in the dupilumab arms had higher percentage values of conjunctivitis (every 2 weeks, 9.8%; every 4 weeks, 10.8%; placebo, 4.7%) and injection-site reactions (every 2 weeks, 8.5%; every 4 weeks, 6.0%; placebo, 3.5%), and lower nonherpetic skin infections (every 2 weeks, 9.8%; every 4 weeks, 9.6%; placebo, 18.8%).

Conclusions and Relevance

In this study, dupilumab significantly improved AD signs, symptoms, and quality of life in adolescents with moderate to severe AD, with an acceptable safety profile. Placebo-corrected efficacy and safety of dupilumab were similar in adolescents and adults.

Trial Registration

ClinicalTrials.gov identifier: NCT03054428.

Laboratory safety of dupilumab in moderate-to-severe atopic dermatitis: results from three phase III trials (LIBERTY AD SOLO 1, LIBERTY AD SOLO 2, LIBERTY AD CHRONOS)

Background

Dupilumab [a monoclonal antibody blocking the shared receptor subunit for interleukin (IL)‐4 and IL‐13] is approved for patients aged ≥ 12 years with inadequately controlled, moderate‐to‐severe atopic dermatitis (AD). Dupilumab trials of up to 52 weeks demonstrated efficacy and a favourable safety profile in patients with moderate‐to‐severe AD inadequately controlled with topical medications.

Objectives

To further characterize the safety of dupilumab by evaluating clinical laboratory findings from three randomized, double‐blinded, placebo‐controlled phase III trials (LIBERTY AD SOLO 1 & 2 and LIBERTY AD CHRONOS).

Methods

Patients were randomized 1 : 1 : 1 (SOLO 1 & 2) or 3 : 1 : 3 (CHRONOS) for 16 and 52 weeks, respectively, to dupilumab weekly, every 2 weeks or placebo. CHRONOS patients received a standardized concomitant topical corticosteroid regimen. Laboratory outcomes were summarized descriptively in 1376 patients from SOLO 1 & 2 and 740 from CHRONOS.

Results

Treatment groups had similar results in baseline laboratory parameters. Platelets and neutrophils showed mild decreases from baseline in dupilumab vs. placebo groups. Some dupilumab‐treated patients had small transient increases in eosinophils. Grade 3 eosinophilia was reported in < 1% of dupilumab‐treated and placebo‐treated patients; no adverse events were associated with eosinophilia. Lactate dehydrogenase levels decreased from baseline during dupilumab treatment in all trials. No clinically meaningful changes were observed between treatment groups in other haematology, chemistry or urinalysis parameters.

Conclusions

There were no clinically important changes in routine laboratory parameters that could be attributed to dupilumab. This study supports the use of dupilumab as a systemic treatment for moderate‐to‐severe AD that does not require laboratory monitoring.

What's already known about this topic?

Long‐term treatment of atopic dermatitis (AD) with conventional immunosuppressive agents is limited by the risk of significant side‐effects and a need for repeated tests to monitor haematological and/or organ (e.g. liver, kidney) toxicities.

Dupilumab [a monoclonal antibody blocking the shared receptor subunit for interleukin (IL)‐4 and IL‐13] is approved for the treatment of patients with inadequately controlled, moderate‐to‐severe AD.

In 16‐week and 52‐week studies, dupilumab demonstrated a positive risk/benefit profile in moderate‐to‐severe AD.

What does this study add?

This study is the first comprehensive analysis of dupilumab laboratory safety data of the 16‐week SOLO 1 & 2 (pooled N = 1376) and 52‐week CHRONOS (N = 740) trials, demonstrating an absence of clinically important changes in haematology, serum chemistry and urinalysis parameters in patients with moderate‐to‐severe AD treated with dupilumab.

Our data support the use of dupilumab as a systemic treatment for the long‐term management of moderate‐to‐severe AD without routine laboratory monitoring in clinical practice.

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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.

Evaluation of Potential Disease-Mediated Drug-Drug Interaction in Patients With Moderate-to-Severe Atopic Dermatitis Receiving Dupilumab

This open‐label drug–drug interaction study assessed whether blockade by dupilumab of interleukin (IL)‐4 and IL‐13 signaling affects the pharmacokinetics of drugs metabolized by cytochrome P450 (CYP450) enzymes. The pharmacokinetics of five CYP450 substrates given orally (midazolam, omeprazole, S‐warfarin, caffeine, and metoprolol, metabolized by CYP3A, CYP2C19, CYP2C9, CYP1A2, and CYP2D6, respectively) were evaluated before and 28 days after initiation of dupilumab treatment (subcutaneous 300 mg weekly) in 14 patients with moderate‐to‐severe atopic dermatitis. Dupilumab had no clinically relevant effects on the pharmacokinetics of CYP450 substrates, provided substantial clinical benefit, and was generally well tolerated. Only one serious adverse event was reported, an episode of systemic inflammatory response syndrome that resolved after treatment was discontinued. In summary, blockade of IL‐4/IL‐13 signaling in patients with type 2 inflammation does not appear to significantly affect CYP450 enzyme activities; the use of dupilumab in atopic dermatitis patients is unlikely to influence the pharmacokinetics of CYP450 substrates.

Dupilumab for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common, chronic, inflammatory skin disorder with high physical and emotional burden. AD usually starts in early childhood and has a heterogeneous course. Emerging evidence suggests that IL-4 and IL-13 are key cytokines in the immunopathogenesis of AD. Dupilumab is a monoclonal antibody directed against IL-4 receptor α subunit, that blocks both IL-4 and IL-13 signaling. Data from Phase I-III studies revealed that dupilumab, administered as monotherapy or with topical corticosteroids, is effective and well tolerated in the treatment of adult patients with moderate-to-severe AD. A large proportion of patients receiving dupilumab had significant improvements in multiple efficacy indexes, including Eczema Area and Severity Index, Investigator's Global Assessment and SCORing Atopic Dermatitis scores. These results introduce a new era of targeted therapies in the management of AD.

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.

The Genetics and Epigenetics of Atopic Dermatitis-Filaggrin and Other Polymorphisms

Atopic dermatitis (AD) is a chronic inflammatory skin disease caused by a combination of genetic and environmental factors. Genetic evidences depict a complex network comprising by epidermal barrier dysfunctions and dysregulation of innate and adaptive immunity in the pathogenesis of AD. Mutations in the human filaggrin gene (FLG) are the most significant and well-replicated genetic mutation associated with AD, and other mutations associated with epidermal barriers such as SPINK5, FLG-2, SPRR3, and CLDN1 have all been linked to AD. Gene variants may also contribute to the abnormal innate and adaptive responses found in AD, including mutations in PRRs and AMPs, TSLP and TSLPR, IL-1 family cytokines and receptors genes, vitamin D pathway genes, FCER1A, and Th2 and other cytokines genes. GWAS and Immunochip analysis have identified a total of 19 susceptibility loci for AD. Candidate genes at these susceptibility loci identified by GWAS and Immunochip analysis also suggest roles for epidermal barrier functions, innate and adaptive immunity, interleukin-1 family signaling, regulatory T cells, the vitamin D pathway, and the nerve growth factor pathway in the pathogenesis of AD. Increasing evidences show the modern lifestyle (i.e., the hygiene hypothesis, Western diet) and other environmental factors such as pollution and environmental tobacco smoke (ETS) lead to the increasing prevalence of AD with the development of industrialization. Epigenetic alterations in response to these environmental factors, including DNA methylation and microRNA related to immune system and skin barriers, have been found to contribute to the pathogenesis of AD. Genetic variants and epigenetic alteration might be the key tools for the molecular taxonomy of AD and provide the background for the personalized management.

Erythroid Differentiation Regulator 1 as a Novel Biomarker for Hair Loss Disorders

Erythroid differentiation regulator 1 (Erdr1) is known to be involved in the inflammatory process via regulating the immune system in many cutaneous disorders, such as psoriasis and rosacea. However, the role of Erdr1 in various hair loss disorders remains unclear. The aim of this study was to investigate the putative role of Erdr1 in alopecias. Skin samples from 21 patients with hair loss disorders and five control subjects were retrieved, in order to assess their expression levels of Erdr1. Results revealed that expression of Erdr1 was significantly downregulated in the epidermis and hair follicles of patients with hair loss disorders, when compared to that in the control group. In particular, the expression of Erdr1 was significantly decreased in patients with alopecia areata. We propose that Erdr1 downregulation might be involved in the pathogenesis of hair loss, and could be considered as a novel biomarker for hair loss disorders.

Biomarkers for Atopic Dermatitis in Children

Numerous studies investigating the correlations between the severity of atopic dermatitis (AD) and various biomarkers have been reported over the past few decades. Recent studies have indicated that certain soluble mediators, including chemokines (such as thymus and activation-regulated chemokine/C-C motif chemokine ligand [CCL]17 and macrophage-derived chemokine/CCL22) and cytokines (such as thymic stromal lymphopoietin), could be good markers of inflammation in AD. This review focuses on circulating biomarkers of AD, including pediatric AD.

Role of interleukin-18 in the pathophysiology of allergic diseases

Interleukin (IL)-18 is an IL-1 family cytokine expressed by macrophages, dendritic cells, epithelial cells, and keratinocytes and is implicated in various aspects of both the innate and adaptive immune systems. IL-18 signals similar to IL-1β intracellularly to activate gene transcription. Since its discovery, IL-18 has been demonstrated to play a key role in pathogen defense from helminths and some bacteria. Recently however, evidence has accumulated that IL-18 expression is increased in many presentations of allergic disease. A pathologic role for IL-18 includes stimulating mast cell and basophil degranulation, recruiting granulocytes to sites of inflammation, increasing cytotoxic activity of natural killer (NK) and NK-T cells, inducing Immunoglobulin (Ig)E production and isotype switching, and affecting a broad range of T cells to promote a type II helper T cell (Th2) response. Evidence and importance of these effects are presented, including novel results from our lab implicating IL-18 in the direct expansion of mast cells, basophils, and other myeloid-lineage cells from bone-marrow precursors. The development of urticaria, asthma, dermatitis, rhinitis, and eosinophilic disorders all have demonstrated correlations to increased IL-18 levels either in the tissue or systemically. IL-18 represents a novel site of immune regulation in not only allergic conditions, but also autoimmune diseases and other instances of aberrant immune functioning. Diagrammatic summarized abstract for readers convinance is presented in Fig. 1.

Biomarkers for atopic dermatitis: a systematic review and meta-analysis

PURPOSE OF REVIEW

A large number of studies investigating the correlation between severity of atopic dermatitis and various biomarkers have been published over the past decades. The aim of this review was to identify, evaluate and synthesize the evidence examining the correlation of biomarkers with disease severity in atopic dermatitis patients, something that has not been performed previously.

RECENT FINDINGS

Three electronic databases were systematically searched and relevant studies were selected for inclusion. A total of 222 articles, reporting on 115 different biomarkers in 30 063 patients, were critically appraised. Studies were divided into two main groups. The first group consisted of longitudinal randomized controlled trials and cohort studies, which reported measurements at multiple time points. The second contained cross-sectional studies that reported only one measurement per patient. Out of 222 articles, 108 articles reported sufficient data for meta-analysis. Only four biomarkers were eligible for meta-analysis in the longitudinal group, and nine in the cross-sectional group.

SUMMARY

Serum thymus and activation-regulated chemokine (TARC) was found to be the most reliable biomarker studied, showing pooled correlation coefficients of 0.60 (95% CI 0.48-0.70) and 0.64 (95% CI 0.57-0.70) in longitudinal and cross-sectional studies, respectively. Additional biomarkers that could prove useful but require additional research include serum cutaneous T-cell attracting chemokine (CTACK), sE-selectin, macrophage-derived chemokine (MDC), lactate dehydrogenase (LDH) and interleukin (IL)-18.

Drug evaluation review: dupilumab in atopic dermatitis

Atopic dermatitis (AD) is characterized by type 2 helper T (Th2) cell-driven inflammation. Dupilumab is a fully human monoclonal antibody directed against the IL-4 receptor α subunit that blocks the signaling of IL-4 and IL-13, both key cytokines in Th2-mediated pathways. In Phase I and II studies of adults with moderate-to-severe AD, dupilumab administered as monotherapy or with topical corticosteroids resulted in rapid, significant improvements in clinical efficacy, patient-reported outcomes, and Th2-related serum and tissue biomarkers, and shifted the RNA expression profile of lesional skin to a more nonlesional signature. In all clinical studies to date, dupilumab has shown a favorable safety profile with no dose-limiting toxicity. The robust effects of dupilumab on skin inflammation and pruritus confirm the pathogenic role of IL-4 and IL-13 signaling in adult AD, and further support the application of Th2 cytokine antagonists in the treatment of this disease.

Coexistence of 2282del4 FLG gene mutation and IL-18 -137G/C gene polymorphism enhances the risk of atopic dermatitis

Introduction

Atopic dermatitis (AD) pathogenesis appears in the context of the correlation between cornified envelope proteins and immunological factors.

Aim

To estimate the association between FLG R501X and 2282del4 gene mutations, –137 G/C IL-18 and –1112 C/T IL-13 gene polymorphisms and their influence on AD course and the risk in the Polish population.

Material and methods

One hundred and fifty-two AD patients and 123 healthy volunteers were included into the study. Amplification refractory mutation system – polymerase chain reaction method was used.

Results

2282del4 FLG mutation, predominant (p = 0.04) in Polish AD patients, enhanced the risk of AD (OR = 2.35; p = 0.01) and was associated with itch (p = 0.023). GG genotype of IL-18 was prevailing in AD (p < 0.0001), associated with elevated IgE levels (p = 0.00074) and pruritus (p < 0.0001). GG genotype and G-allele in –137 position of IL-18 increased AD risk (OR = 5.4; p = 0.0001, respectively, OR = 5.3; p = 0.000029). –1112 C/T polymorphism of IL-13 was associated with elevated IgE levels (p = 0.00049), pruritus (p = 0.0005), SCORAD score (p = 0.02), concomitant asthma (p = 0.0087) and AD risk (OR = 2.02; p = 0.012). Coexistence of 2282del4 or R501X FLG gene mutation with GG genotype of IL-18 was associated with a 6-fold higher risk of AD (OR = 5.8; p = 0.00013), contrary to combined occurrence of FLG mutations with T-allele in –1112 position of IL-13 gene (OR = 0.12; p = 0.1).

Conclusions

2282del4 FLG mutation similarly to GG genotype and G-allele in –137 position of IL-18 gene enhance the risk of AD in the Polish population. Coexistence of FLG mutations with GG genotype of IL-18 may be helpful to estimate chances of AD development.

Effect of Acer tegmentosum bark on atopic dermatitis-like skin lesions in NC/Nga mice

ETHNOPHARMACOLOGICAL RELEVANCE

Atopic dermatitis (AD) is a chronic and relapsing inflammatory condition characterized by pruritic and eczematous skin lesions that requires safe and effective pharmacological therapy. The bark of Acer tegmentosum Maxim trees has been used in Korean folk and traditional medicine to treat abscesses, surgical bleeding, liver diseases, and AD.

AIM OF STUDY

To investigate the therapeutic effect of A. tegmentosum, on a mouse model of Dermatophagoides farinae (Df)-induced AD.

METHODS

Development of AD-like skin lesions was induced by repetitive skin contact with barrier-disrupted backs of NC/Nga mice with Df body ointment, and the effects of A. tegmentosum were evaluated on the basis of histopathological skin assessment results, ear swelling, and cytokine production in the dorsal skin. The component of A. tegmentosum, salidroside, inhibited the production of TSLP in KCMH-1 cells, which indicated that its production could be pharmacologically regulated.

RESULTS

Topical application of A. tegmentosum for 1 week after Df body ointment challenge significantly reduced ear swelling and improved dorsal skin lesions. Suppression of dermatitis by combined therapy was accompanied by a decrease in the skin level of Th2 cytokines, such as interleukin (IL)-4, IL-5 and IL-13, plasma levels of thymus and activation-regulated chemokine, and IgE. Induction of thymic stromal lymphopoietin, which leads to a systemic Th2 response, was also reduced in in vivo and in vitro by A. tegmentosum and salidroside.

CONCLUSIONS

Our findings suggest that A. tegmentosum treatment has a significant therapeutic effect on Df-induced AD-like skin lesions on NC/Nga mice through inhibition of thymic stromal lymphopoietin and IgE via a mechanism that may inhibit Th2-mediated immune responses. These results suggest that A. tegmentosum and salidroside may be useful tools for the treatment of AD.

Medium-dose ultraviolet A1 phototherapy and mRNA expression of TSLP, TARC, IL-5, and IL-13 in acute skin lesions in atopic dermatitis

BACKGROUND

The mechanisms responsible for the efficacy of ultraviolet A1 (UVA1) in the treatment of atopic dermatitis (AD) are not fully understood.

OBJECTIVES

This study was designed to investigate mRNA expression of thymic stromal lymphopoietin (TSLP), thymus- and activation-regulated chemokine (TARC), interleukin-5 (IL-5), and IL-13 in AD before and after UVA1 therapy, to determine correlations among them, and to examine whether UVA1 influences their expression and whether it is associated with UVA1 efficacy.

METHODS

Twenty-five patients with AD underwent medium-dose UVA1 phototherapy. Before and after UVA1, biopsies from acute skin lesions were studied using reverse transcription and real-time polymerase chain reaction.

RESULTS

Levels of mRNA TSLP correlated with those of TARC, IL-5, and IL-13, and levels of TARC correlated with those of IL-5 and IL-13, both before and after UVA1. Expression of IL-5 correlated with that of IL-13 only before UVA1. SCORAD (SCORing of Atopic Dermatitis) indices correlated with levels of TARC and IL-5 before irradiation. After UVA1, no mRNA level correlated with the SCORAD index. Phototherapy with UVA1 improved SCORAD values (P < 0.001) and increased expression of TARC (P < 0.05) but did not affect mRNA expression of TSLP, IL-5, or IL-13.

CONCLUSIONS

Expression levels of the mediators TSLP, TARC, IL-5, and IL-13 in AD are interrelated. Phototherapy with UVA1 improves SCORAD indices and increases expression of TARC but has no direct effects on the expression of other molecules. It is likely that UVA1 also interferes with or acts via intermediators on the link between IL-5 and IL-13.

Targeting chemokine receptors in disease--a case study of CCR4

Since their early 1990s, the chemokine receptor family of G protein-coupled receptors (GPCRs) has been the source of much pharmacological endeavour. Best known for their key roles in recruiting leukocytes to sites of infection and inflammation, the receptors present themselves as plausible drug targets for therapeutic intervention. In this article, we will focus our attention upon CC Chemokine Receptor Four (CCR4) which has been implicated in diseases as diverse as allergic asthma and lymphoma. We will review the discovery of the receptors and their ligands, their perceived roles in disease and the successful targeting of CCR4 by both small molecule antagonists and monoclonal antibodies. We will also discuss future directions and strategies for drug discovery in this field.

The Inflammatory Caspases-1 and -11 Mediate the Pathogenesis of Dermatitis in Sharpin-Deficient Mice

Chronic proliferative dermatitis in mice (cpdm) is a spontaneous multiorgan inflammatory disorder with pathological hallmarks similar to atopic dermatitis and psoriasis in humans. Cpdm mice lack expression of SHANK-associated RH domain-interacting protein, an adaptor of the linear ubiquitin assembly complex, which acts in the NF-κB pathway to promote inflammation and protect from apoptosis and necroptosis. Although skin inflammation in cpdm mice is driven by TNF- and RIPK1-induced cell death, the contribution of initiating innate immunity sensors and additional inflammatory pathways remains poorly characterized. In this article, we show that inflammasome signaling, including the expression and activation of the inflammatory caspase-1 and -11 and IL-1 family cytokines, was highly upregulated in the skin of cpdm mice prior to overt disease onset. Genetic ablation of caspase-1 and -11 from cpdm mice significantly reduced skin inflammation and delayed disease onset, whereas systemic immunological disease persisted. Loss of Nlrp3 also attenuated skin disease, albeit more variably. Strikingly, induction of apoptosis and necroptosis effectors was sharply decreased in the absence of caspase-1 and -11. These results position the inflammasome as an important initiating signal in skin disease pathogenesis and provide novel insights about inflammasome and cell death effector cross-talk in the context of inflammatory diseases.

Recombinant erythroid differentiation regulator 1 inhibits both inflammation and angiogenesis in a mouse model of rosacea

The erythroid differentiation regulator 1 (Erdr1), which is a novel and highly conserved factor, was recently reported to be negatively regulated by IL-18 and to play a crucial role as an antimetastatic factor. IL-18 is a proinflammatory cytokine that functions as an angiogenic mediator in inflammation. Rosacea is a chronic inflammatory skin disorder that is characterized by abnormal inflammation and vascular hyperactivity of the facial skin. To determine whether Erdr1 contributes to the regulation of the chronic inflammatory process in the development of rosacea, an immunohistochemical analysis was performed in healthy donors and patients with rosacea. In this study, we showed that Erdr1 was downregulated, whereas IL-18 was upregulated, in patients with rosacea, which led us to question the role of Erdr1 in this disorder. Moreover, a rosacea-like BALB/c mouse model was used to determine the role of Erdr1 in rosacea in vivo. LL-37 injection induced typical rosacea features, including erythema, telangiectasia and inflammation. Treatment with recombinant Erdr1 (rErdr1) resulted in a significant reduction of erythema, inflammatory cell infiltration (including CD4(+) and CD8(+) T cells), and microvessel density with vascular endothelial growth factor (VEGF). Taken together, our findings suggest that rErdr1 may be involved in attenuating the inflammation and angiogenesis associated with the pathogenesis of rosacea. Thus, these results provide new insight into the mechanism involved in this condition and indicate that rErdr1 could be a potential target for therapeutic intervention of rosacea.

Solanum tuberosum L. cv Jayoung Epidermis Extract Inhibits Mite Antigen-Induced Atopic Dermatitis in NC/Nga Mice by Regulating the Th1/Th2 Balance and Expression of Filaggrin

Solanum tuberosum L. cv Jayoung (JY) is a potato with dark purple flesh and contains substantial amounts of polyphenols. In this study, we evaluated the therapeutic effects of S. tuberosum L. cv JY in a mouse model of Dermatophagoides farinae body (Dfb)-induced atopic dermatitis (AD). The ethanol extract of the peel of JY (EPJ) ameliorated Dfb-induced dermatitis severity, serum levels of immunoglobulin E (IgE) and thymus and activation-regulated chemokine. Histological analysis of the skin also revealed that EPJ treatment significantly decreased mast cell infiltration. The suppression of dermatitis by EPJ treatment was accompanied by a decrease in the skin levels of type 2 helper T-cell cytokines such as interleukin (IL)-4, IL-5, and IL-13. The induction of thymic stromal lymphopoietin, which leads to a systemic Th2 response, was also decreased in the skin by EPJ. Nuclear translocation of nuclear factor-κB p65 was decreased by EPJ in Dfb-induced NC/Nga mice. The protein expression of filaggrin in the AD-like skin lesions was restored by EPJ treatment. These results suggested that EPJ may be a potential therapeutic tool for the treatment of AD.

Specific immunotherapy in atopic dermatitis

Allergen specific immunotherapy (SIT) using house dust mite (HDM) extracts has been performed mainly with patients of asthma and allergic rhinitis. In the meanwhile, there has been a long debate on the efficacy of SIT in atopic dermatitis (AD) with only a few double-blind placebo-controlled trials. However, several randomized controlled trials of SIT in AD revealed significant improvement of clinical symptoms and also, positive result was shown by a following meta-analysis study of these trials. In order to predict and evaluate the treatment outcome, finding a biomarker that can predict treatment responses and treatment end-points is critical but it is very challenging at the same time due to the complexity of causes and mechanisms of AD. Other considerations including standardization of the easiest and safest treatment protocol and optimizing the treatment preparations should be studied as well. This review summarizes the basics of SIT in AD including the brief mechanisms, treatment methods and schedules, and also highlights the clinical efficacy of SIT in AD along with mild, controllable adverse reactions. Immunologic effects and studies of various biomarkers are also introduced and finally, future considerations with upcoming studies on SIT were discussed.