Serum biomarker profiles suggest that atopic dermatitis is a systemic disease

Skin and systemic inflammation in adults with atopic dermatitis before and after whole-body topical betamethasone 17-valerate 0.1% or tacrolimus 0.1% treatment: A randomized controlled study

BACKGROUND

Atopic dermatitis (AD) is mainly driven by type 2 inflammation and often treated with topical agents. Studies comparing differences in biomarkers between these treatments are lacking.

OBJECTIVES

The aim of this study was to evaluate the effects of topical betamethasone 17-valerate 0.1% and tacrolimus 0.1% ointment on skin barrier function and inflammatory biomarkers in skin and blood in adults with AD.

METHODS

In this randomized parallel-group double-blind double-dummy active-comparator study design, 36 adults with AD were treated with either whole-body topical corticosteroid (betamethasone ointment 0.1% plus placebo once daily, n = 18) or calcineurin inhibitor (tacrolimus ointment 0.1% twice daily, n = 18). At baseline, after 2 weeks of daily treatment and after further 4 weeks of twice-weekly maintenance treatment, we evaluated AD severity, levels of natural moisturizing factor (NMF) and cytokines in the skin and blood and characterized circulating T cells.

RESULTS

Mean AD severity at baseline corresponded to moderate disease and decreased significantly in both groups. Levels of NMF increased significantly in the tacrolimus group after 2 weeks of treatment (p = 0.002) and tended to increase more than betamethasone at week 6 (p = 0.06). Most skin cytokines decreased with both treatments. However, IL-8, IL-18, IL-22, IP-10, MDC, MMP-9 and TARC were significantly more decreased with betamethasone than tacrolimus after 2 weeks, while after 6 weeks this was only the case for IL-8 and MMP-9. Approximate half of the systemic cytokines decreased significantly with both treatments, but betamethasone decreased MDC significantly more after 2 weeks of treatment. T-cell characterization analyses indicated slight differences in the expression and activation of T cells between groups.

CONCLUSION

Topical treatment of AD with betamethasone and tacrolimus ointment effectively reduced disease severity, cutaneous and systemic inflammatory markers. Betamethasone was more effective in decreasing inflammation, but tacrolimus improved skin hydration (NMF levels) more than betamethasone.

Exploring causal correlations between circulating cytokines and atopic dermatitis: a bidirectional two-sample Mendelian randomization study

Objectives

Numerous observational studies have reported associations between circulating cytokines and atopic dermatitis (AD); however, the causal relationships between them remain unclear. To explore the causal correlations and direction of causal effects between AD and levels of 91 circulating cytokines.

Methods

Two-sample Mendelian randomization (MR) analyses were conducted to examine the causal relationships between 91 circulating cytokines and AD using summary statistics from genome-wide association studies (GWAS). Reverse MR analyses were performed to investigate reverse causation. Pleiotropy and heterogeneity tests were conducted to assess the robustness of the findings. Additional transcriptome database and clinical peripheral blood mononuclear cells (PBMCs) samples were utilized to validate the results of MR analyses.

Results

Levels of interleukin (IL)-13, IL-18 Receptor 1, Tumor necrosis factor ligand superfamily member 14 (TNFSF14), TNF-related activation-induced cytokine (TRANCE), C-X-C motif chemokine (CXCL)11, IL-33, TNF-beta and CD5 were suggestively associated with the risk of AD (odds ratio, OR: 1.202, 95% CI: 1.018-1.422, p = 0.030; OR: 1.029, 95% CI: 1.029-1.157, p = 0.004; OR: 1.159, 95% CI: 1.018-1.320, p = 0.026; OR: 1.111, 95% CI: 1.016-1.214, p = 0.020; OR: 0.878, 95% CI: 0.783-0.984, p = 0.025; OR: 0.809, 95% CI: 0.661-0.991, p = 0.041; OR: 0.945, 95% CI: 0.896-0.997, p = 0.038; OR: 0.764, 95% CI: 0.652-0.895, p = 8.26e-04). In addition, levels of cytokines including Axin-1, CXCL5, CXCL10, Oncostatin-M (OSM), Sulfotransferase 1A1 (SULT1A1) and TNFSF14 were suggested to be consequences of AD (Beta: -0.080, p = 0.016; Beta: -0.062, p = 0.036; Beta: -0.066, p = 0.049; Beta: -0.073, p = 0.013; Beta: -0.089, p = 0.008; Beta: -0.079, p = 0.031). IL-13, IL-18R1, TNFSF14, and TRANCE were upregulated in both lesional skin biopsies and PBMCs from AD patients.

Conclusion

The study indicates that several cytokines, including IL-13, IL-18R1, TNFSF14, TRANCE, CXCL11, IL-33, TNF-beta, and CD5, are upstream of AD development, whereas a few circulating cytokines are potentially downstream in the development of AD.

The association between atopic dermatitis and inflammatory bowel disease in adults: A cross-sectional study in a specialized atopic dermatitis clinic

BACKGROUND

Atopic dermatitis (AD) and inflammatory bowel disease (IBD) share genetic susceptibility loci with immune regulation functions. Atopic dermatitis was associated with IBD mostly in database studies.

OBJECTIVE

To assess whether AD is associated with an increased prevalence of IBD in a tertiary dermatology clinic.

METHODS

A retrospective cross-sectional analysis using medical records of adults with verified AD followed up at an AD clinic, compared with age- and sex-matched (1:2) controls from the general dermatology clinic in the same hospital.

RESULTS

Overall, 9/364 (2.47%) of patients with AD had verified IBD, compared with 7/725 (0.97%) of controls (p = 0.0512). In multivariable logistic regression adjusting for age, gender and smoking, the association became significant (adjusted OR = 3.89, 95% CI: 1.28-11.85). Stratified for AD severity, only moderate-to-severe AD was associated with IBD (p = 0.035), with an adjusted OR of 4.45 (95% CI: 1.43-13.90). Mild AD was not associated with IBD, but the study was not powered for this sub-analysis. In the AD group, older age was associated with IBD (p = 0.0172).

CONCLUSION

This study, in a robustly verified cohort of patients, supports an association between AD, especially the moderate-to-severe forms, and IBD. A multidisciplinary approach for patients with moderate-to-severe AD should extend to consider IBD.

IL-26 Potentiates Type 2 Skin Inflammation in the Presence of IL-1β

Atopic dermatitis (AD) is a debilitating inflammatory skin disorder. Biologics targeting the IL-4/IL-13 axis are effective in AD, but there is still a large proportion of patients who do not respond to IL-4R blockade. Further exploration of potentially pathogenic T-cell-derived cytokines in AD may lead to new effective treatments. This study aimed to investigate the downstream effects of IL-26 on skin in the context of type 2 skin inflammation. We found that IL-26 alone exhibited limited inflammatory activity in the skin. However, in the presence of IL-1β, IL-26 potentiated the secretion of TSLP, CXCL1, and CCL20 from human epidermis through Jak/signal transducer and activator of transcription signaling. Moreover, in an in vivo AD-like skin inflammation model, IL-26 exacerbated skin pathology and locally increased type 2 cytokines, most notably of IL13 in skin T helper cells. Neutralization of IL-1β abrogated IL-26-mediated effects, indicating that the presence of IL-1β is required for full IL-26 downstream action in vivo. These findings suggest that the presence of IL-1β enables IL-26 to be a key amplifier of inflammation in the skin. As such, IL-26 may contribute to the development and pathogenesis of inflammatory skin disorders such as AD.

Integrating multi-omics approaches in deciphering atopic dermatitis pathogenesis and future therapeutic directions

Atopic dermatitis (AD), a complex and heterogeneous chronic inflammatory skin disorder, manifests in a spectrum of clinical subtypes. The application of genomics has elucidated the role of genetic variations in predisposing individuals to AD. Transcriptomics, analyzing gene expression alterations, sheds light on the molecular underpinnings of AD. Proteomics explores the involvement of proteins in AD pathophysiology, while epigenomics examines the impact of environmental factors on gene expression. Lipidomics, which investigates lipid profiles, enhances our understanding of skin barrier functionalities and their perturbations in AD. This review synthesizes insights from these omics approaches, highlighting their collective importance in unraveling the intricate pathogenesis of AD. The review culminates by projecting future trajectories in AD research, particularly the promise of multi-omics in forging personalized medicine and novel therapeutic interventions. Such an integrated multi-omics strategy is poised to transform AD comprehension and management, steering towards more precise and efficacious treatment modalities.

Evaluating the clinical utility of the Atopic Dermatitis Control Tool: measurement properties and agreement between patients' responses and clinicians' impressions of atopic dermatitis control

Previous analyses have demonstrated the validity and reliability of the Atopic Dermatitis Control Tool (ADCT) in assessing patient-perceived control of atopic dermatitis (AD). We evaluated levels of agreement between patient and clinician assessments of AD control using the ADCT and clinician global assessment of control, respectively, providing further support to the measurement properties of the ADCT.

Proteomic alterations in patients with atopic dermatitis

INTRODUCTION

Atopic Dermatitis (AD) is the most common inflammatory skin disease with a complex and multifactorial pathogenesis. The use of proteomics in understanding AD has yielded the discovery of novel biomarkers and may further expand therapeutic options.

AREAS COVERED

This review summarizes the most recent proteomic studies and the methodologies used in AD. It describes novel biomarkers that may monitor disease course and therapeutic response. The review also highlights skin and blood biomarkers characterizing different AD phenotypes and differentiates AD from other inflammatory skin disorders. A literature search was conducted by querying Scopus, Google Scholar, Pubmed/Medline, and Clinicaltrials.gov up to June 2023.

EXPERT OPINION

The integration of proteomics into research efforts in atopic dermatitis has broadened our understanding of the molecular profile of AD through the discovery of new biomarkers. In addition, proteomics may contribute to the development of targeted treatments ultimately improving personalized medicine. An increasing number of studies are utilizing proteomics to explore this heterogeneous disease.

Mind and skin: Exploring the links between inflammation, sleep disturbance and neurocognitive function in patients with atopic dermatitis

Atopic dermatitis (AD) is a chronic, pruritic and inflammatory, dry skin condition with many known comorbidities. These include airway disease, food allergies, atopic eye disease and autoimmune conditions. Furthermore, there is often significant sleep disturbance as well as increased psychological distress and mental health problems. Severe AD therefore often has a significant impact on the quality of life of both patients and their families. In this review we discuss recent findings on the putative links between AD, its association with itch, sleep disturbance and neuropsychiatric morbidity, including the role of inflammation in these conditions. Itch was thought to predominantly drive sleep disruption in AD. We now understand changes in sleep influence immune cell distribution and the associated inflammatory cytokines, which suggests a bidirectional relationship between AD and sleep. We also increasingly recognize inflammation as a key driver in psychological symptoms and disorders. The link between cutaneous, systemic and possible brain inflammation could at least in part be driven by the sleep deprivation and itch-driven neuronal proliferation seen in AD.

Immunoglobulin E autoantibodies in atopic dermatitis associate with Type-2 comorbidities and the atopic march

BACKGROUND

Autoreactive immunoglobulin E (IgE) antibodies to self-peptides within the epidermis have been identified in patients with atopic dermatitis (AD). Prevalence, concomitant diseases, patient characteristics, and risk factors of IgE autoantibody development remain elusive. We aimed to determine IgE autoantibodies in serum samples (n = 672) from well-characterized patients with AD and controls (1.2-88.9 years).

METHODS

Atopic dermatitis patients were sub-grouped in AD with comorbid Type-2 diseases ("AD + Type 2"; asthma, allergic rhinitis, food allergy, n = 431) or "solely AD" (n = 115). Also, subjects without AD but with Type-2 diseases ("atopic controls," n = 52) and non-atopic "healthy controls" (n = 74) were included. Total proteins from primary human keratinocytes were used for the immunoassay to detect IgE autoantibodies. Values were compared to already known positive and negative serum samples.

RESULTS

Immunoglobulin E autoantibodies were found in 15.0% (82/546) of all analyzed AD-patients. "AD + Type 2" showed a higher prevalence (16.4%) than "solely AD" (9.6%). "Atopic controls" (9.6%) were comparable with "solely AD" patients, while 2.7% of healthy controls showed IgE autoantibodies. Of those with high levels of IgE autoantibodies, 15 out of 16 were patients with "AD + Type 2". AD patients with IgE autoantibodies were younger than those without. Patients with IgE autoreactivity also displayed higher total serum IgE levels. Factors that affected IgE autoantibody development were as follows: birth between January and June, cesarean-section and diversity of domestic pets.

CONCLUSIONS

Immunoglobulin E autoantibodies in AD seem to associate with the presence of atopic comorbidities and environmental factors. The potential value of IgE autoantibodies as a predictive biomarker for the course of AD, including the atopic march, needs further exploration.

Assessment of Subclinical Atherosclerosis in Children with Atopic Dermatitis

INTRODUCTION

Data from studies conducted to date have evaluated clinical atherosclerotic conditions in adult patients with atopic dermatitis (AD). Subclinical atherosclerotic changes that are a precursor of atherosclerotic conditions may begin in childhood. The aim of this study was to investigate the presence of subclinical atherosclerosis in pediatric patients with AD and to determine the associated risk factors.

METHODS

A total of 59 patients who were referred to our department over a 6-month period and diagnosed with AD, and 53 healthy controls with a similar age and gender were included in the study. Subclinical atherosclerosis markers (carotid intima media thickness [CIMT], distensibility, stiffness, and strain) were measured using conventional echocardiography. The patients' age, SCORAD index, and duration of symptoms were recorded. Serum total immunoglobulin E, C-reactive protein (CRP), blood lipid profile, and complete blood count markers were measured.

RESULTS

The median age of the patients was 61 (10-103) months, and 59.3% of them were male. The patients with AD had a higher CIMT (1.60 ± 0.35 vs. 1.30 ± 0.50 mm) and a lower distensibility (0.006 ± 0.009 vs. 0.01 ± 0.008) and strain (0.10 ± 0.14 vs. 0.19 ± 0.14) than the healthy controls (p < 0.01 for all), but there was no significant difference with regard to stiffness (10.16 ± 21.75 vs. 8.99 ± 12.66). Significant correlations between CIMT and disease duration, age, and the SCORAD index were found (p < 0.01, p < 0.01, and p < 0.05, respectively). No correlation between the subclinical atherosclerosis markers and the other laboratory results was found (p > 0.05 for all).

CONCLUSION

This study demonstrates that pediatric patients with AD may express subclinical atherosclerosis markers. The evaluation of subclinical atherosclerosis in these patients revealed that CIMT may be the most important marker, as it displayed positive correlations with symptom duration, age, and disease severity.

Disease modification in inflammatory skin disorders: opportunities and challenges

Progress in understanding of the mechanisms underlying chronic inflammatory skin disorders, such as atopic dermatitis and psoriasis vulgaris, has led to new treatment options with the primary goal of alleviating symptoms. In addition, this knowledge has the potential to inform on new strategies aimed at inducing deep and therapy-free remission, that is, disease modification, potentially impacting on associated comorbidities. However, to reach this goal, key areas require further exploration, including the definitions of disease modification and disease activity index, further understanding of disease mechanisms and systemic spillover effects, potential windows of opportunity, biomarkers for patient stratification and successful intervention, as well as appropriate study design. This Perspective article assesses the opportunities and challenges in the discovery and development of disease-modifying therapies for chronic inflammatory skin disorders.

Circulating biomarkers are associated with disease severity of chronic hand eczema and atopic dermatitis

BACKGROUND

Although chronic hand eczema (CHE) is a highly prevalent and disabling skin disease, it is currently unknown if CHE is associated with systemic inflammation.

OBJECTIVES

To characterize the plasma inflammatory signature of CHE.

METHODS

Using Proximity Extension Assay technology, we assessed 266 inflammatory and cardiovascular disease risk proteins in the plasma of 40 healthy controls, 57 patients with atopic dermatitis (AD) with active lesions, 11 with CHE and a history of AD (CHEPREVIOUS_AD), and 40 with CHE and no history of AD (CHENO_AD). Filaggrin gene mutation status was also assessed. Protein expression was compared between groups and according to disease severity. Correlation analyses for biomarkers, and clinical- and self-reported variables, were performed.

RESULTS

Very severe CHENO_AD was associated with systemic inflammation when compared with controls. Levels of T helper (Th)2- and Th1-, general inflammation and eosinophil activation markers increased with severity of CHENO_AD, primarily being significantly increased in very severe disease. Significant, positive correlations were found between markers from these pathways and severity of CHENO_AD. Moderate-to-severe but not mild AD displayed systemic inflammation. The Th2 markers C-C motif chemokine (CCL)17 and CCL13 (also known as monocyte chemotactic protein 4) were the top differentially expressed proteins in both very severe CHENO_AD and moderate-to-severe AD, showing a higher fold change and significance in AD. CCL17 and CCL13 levels further correlated positively with disease severity in both CHENO_AD and AD.

CONCLUSIONS

Systemic Th2-driven inflammation is shared between very severe CHE with no history of AD, and moderate-to-severe AD, suggesting that Th2 cell targeting could be effective in several CHE subtypes.

Peripheral Blood Gene Expression Profile of Infants with Atopic Dermatitis

To enhance the understanding of molecular mechanisms and mine previously unidentified biomarkers of pediatric atopic dermatitis, PBMC gene expression profiles were generated by RNA sequencing in infants with atopic dermatitis and age-matched controls. A total of 178 significantly differentially expressed genes (DEGs) (115 upregulations and 63 downregulations) were seen, compared with those in healthy controls. The DEGs identified included IL1β, TNF, TREM1, IL18R1, and IL18RAP. DEGs were validated by real-time RT- qPCR in a larger number of samples from PBMCs of infants with atopic dermatitis aged <12 months. Using the DAVID (Database for Annotation, Visualization and Integrated Discovery) database, functional and pathway enrichment analyses of DEGs were performed. Gene ontology enrichment analysis showed that DEGs were associated with immune responses, inflammatory responses, regulation of immune responses, and platelet activation. Pathway analysis indicated that DEGs were enriched in cytokine‒cytokine receptor interaction, immunoregulatory interactions between lymphoid and nonlymphoid cells, hematopoietic cell lineage, phosphoinositide 3-kinase‒protein kinase B signaling pathway, NK cell‒mediated cytotoxicity, and platelet activation. Furthermore, the protein‒protein interaction network was predicted using the STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) database and visualized with Cytoscape software. Finally, on the basis of the protein‒protein interaction network, 18 hub genes were selected, and two significant modules were obtained. In conclusion, this study sheds light on the molecular mechanisms of pediatric atopic dermatitis and may provide diagnostic biomarkers and therapeutic targets.

Biomarkers in atopic dermatitis

Atopic dermatitis (AD) is a complex and highly heterogeneous inflammatory skin disease. Given the highly heterogeneous character of AD, it is unlikely that every patient will respond equally to a particular treatment. The recent introduction of novel targeted therapies for AD has driven the need for patient stratification based on immunologic biomarkers. We have reviewed the use of different types of biomarkers as potential tools in the movement toward personalized medicine in AD, comprising different ways of endotyping patients with AD based on immunologic profiles and predictive biomarkers. The application of biomarkers will result in better characterization and stratification of patients and allow better comparison of current and new treatments. The ultimate goal will be to switch from the current generalized "one-drug-fits-all" management to more personalized "patient endotype-specific" management.

CD1a promotes systemic manifestations of skin inflammation

Inflammatory skin conditions are increasingly recognised as being associated with systemic inflammation. The mechanisms connecting the cutaneous and systemic disease are not well understood. CD1a is a virtually monomorphic major histocompatibility complex (MHC) class I-like molecule, highly expressed by skin and mucosal Langerhans cells, and presents lipid antigens to T-cells. Here we show an important role for CD1a in linking cutaneous and systemic inflammation in two experimental disease models. In human CD1a transgenic mice, the toll-like receptor (TLR)7 agonist imiquimod induces more pronounced splenomegaly, expansion of the peripheral blood and spleen T cell compartments, and enhanced neutrophil and eosinophil responses compared to the wild-type, accompanied by elevated skin and plasma cytokine levels, including IL-23, IL-1α, IL-1β, MCP-1 and IL-17A. Similar systemic escalation is shown in MC903-induced skin inflammation. The exacerbated inflammation could be counter-acted by CD1a-blocking antibodies, developed and screened in our laboratories. The beneficial effect is epitope dependent, and we further characterise the five best-performing antibodies for their capacity to modulate CD1a-expressing cells and ameliorate CD1a-dependent systemic inflammatory responses. In summary, we show that a therapeutically targetable CD1a-dependent pathway may play a role in the systemic spread of cutaneous inflammation.

Potential biomarkers of atopic dermatitis

Atopic dermatitis (AD) is a chronic, recurrent inflammatory skin disease with a wide range of heterogeneity. Accurate biomarkers or predictors are the keys to instructing personalized tailored precise treatment. The development of technology such as transcriptomics, genomics, and proteomics provides novel insights into the possibility to find potential biomarkers. Meanwhile, emerging minimally invasive methods such as tape stripping were used to reveal different profiles of patients' skin without biopsy. Several potential biomarkers or predictors have been found. In this review, we summarized the current development of potential biomarkers of AD. Nitric oxide synthase 2/inducible nitric oxide synthase (NOS2/iNOS), human beta-defensin-2 (hBD-2), and matrix metalloproteinases 8/9 (MMP8/9) may be the candidate biomarkers for AD diagnosis. Filaggrin (FLG) gene mutation increased the occurrence risk of AD. Fatty-acid-binding protein 5 (FABP5) may serve as an effective biomarker for the atopic march (AM). Squamous cell carcinoma antigen 2 (SCCA2), serum thymus and activation-regulated chemokine (TARC), cutaneous T-cell-attracting chemokine (CTACK), eosinophil-derived neurotoxin (EDN), macrophage-derived chemokine (MDC), lactate dehydrogenase (LDH), and interleukin (IL)-18 can be the candidate biomarkers for disease severity monitoring. IL-17, IL-23, IL-33, and indoleamine 2,3-dioxygenase (IDO1) can be used as predictive biomarkers for AD comorbidities. LDH, TARC, pulmonary and activation-regulated chemokine (PARC), periostin, IL-22, eotaxin-1/3, and IL-8 may be the candidate biomarkers for monitoring treatment effects. There are still unmet needs and a long way to go for more convenient, non-invasive, and effective predictors and biomarkers to better guide personalized precise treatment.

Context-dependent function of TSLP and IL-1β in skin allergic sensitization and atopic march

Atopic diseases, including atopic dermatitis (AD) and asthma, affect a large proportion of the population, with increasing prevalence worldwide. AD often precedes the development of asthma, known as the atopic march. Allergen sensitization developed through the barrier-defective skin of AD has been recognized to be a critical step leading to asthma, in which thymic stromal lymphopoietin (TSLP) was previously shown to be critical. In this study, using a laser-assistant microporation system to disrupt targeted skin layers for generating micropores at a precise anatomic depth of mouse skin, we model allergen exposure superficially or deeply in the skin, leading to epicutaneous sensitization or dermacutaneous sensitization that is associated with a different cytokine microenvironment. Our work shows a differential requirement for TSLP in these two contexts, and identifies an important function for IL-1β, which is independent of TSLP, in promoting allergen sensitization and subsequent allergic asthma.

Allergic sensitisation in the skin can lead to allergic dermatitis and further to airway asthma in a process of atopic march. Here the authors examine the difference between superficial or deep skin sensitisation, characterise the immune cells generated and show differential TSLP and IL-1β involvement.

Immunotherapy in atopic dermatitis

In the past decade, the emergence of biologics targeting human cytokine networks has advanced a new era in atopic dermatitis therapy. Dupilumab, in particular, the most widely studied and used IL-4/IL-13 inhibitor, has been considered a milestone in the treatment of patients with moderate-to-severe atopic dermatitis. In addition to the IL-4 and IL-13 pathways, many other cytokines and receptors have been newly targeted as therapeutic options. In this review, the authors provide an overview of the approved and tested biologics and JAK inhibitors for the treatment of atopic dermatitis, including their advantages and limitations.

Immunological Pathomechanisms of Spongiotic Dermatitis in Skin Lesions of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic pruritic skin disease with a complex pathogenesis underlying its heterogeneous clinical phenotypes and endotypes. The skin manifestation of AD reflects the cytokine milieu of a type-2-dominant immunity axis induced by genetic predisposition, innate immunity dysregulation, epidermal barrier defects, and allergic inflammation. However, the detailed pathomechanism of eczematous dermatitis, which is the principal characteristic of AD, remains unclear. This review examines previous studies demonstrating research progress in this area and considers the immunological pathomechanism of “spongiotic dermatitis”, which is the histopathological hallmark of eczematous dermatitis. Studies in this field have revealed the importance of IgE-mediated delayed-type hypersensitivity, the Fas/Fas-ligand system, and cell-mediated cytotoxicity in inducing the apoptosis of keratinocytes in spongiotic dermatitis. Recent studies have demonstrated that, together with infiltrating CD4 T cells, IgE-expressing dendritic cells (i.e., inflammatory dendritic epidermal cells and Langerhans cells) that capture specific allergens (i.e., house dust mites) are present in the spongiotic epidermis of lichenified eczema in patients with IgE-allergic AD. These findings suggest that IgE-mediated delayed-type hypersensitivity plays a pivotal role in the pathogenesis of spongiotic dermatitis in the skin lesions of AD.

From Skin Barrier Dysfunction to Systemic Impact of Atopic Dermatitis: Implications for a Precision Approach in Dermocosmetics and Medicine

: Atopic dermatitis (AD) affects up to 20% of children and is considered the starting point of the atopic march with the development of food allergy, asthma, and allergic rhinitis. The heterogeneous phenotype reflects distinct and/or overlapping pathogenetic mechanisms with varying degrees of epidermal barrier disruption, activation of different T cell subsets and dysbiosis of the skin microbiome. Here, we review current evidence suggesting a systemic impact of the cutaneous inflammation in AD together with a higher risk of asthma and other comorbidities, especially in severe and persistent AD. Thus, early therapy of AD to restore the impaired skin barrier, modified microbiome, and target type 2 inflammation, depending on the (endo)phenotype, in a tailored approach is crucial. We discuss what we can learn from the comorbidities and the implications for preventive and therapeutic interventions from precision dermocosmetics to precision medicine. The stratification of AD patients into biomarker-based endotypes for a precision medicine approach offers opportunities for better long-term control of AD with the potential to reduce the systemic impact of a chronic skin inflammation and even prevent or modify the course, not only of AD, but possibly also the comorbidities, depending on the patient’s age and disease stage.

Atopic dermatitis: pathomechanisms and lessons learned from novel systemic therapeutic options

Atopic dermatitis (AD) is a chronic, heterogenous, inflammatory skin disorder associated with a high skin-related health burden, typically starting in childhood and often persisting into adulthood. AD is characterized by a wide range of clinical phenotypes, reflecting multiple underlying pathophysiological mechanisms and interactions between genetics, immune system dysregulation, and environmental factors. In this review, we describe the diverse cellular and molecular mechanisms involved in AD, including the critical role of T cell-driven inflammation, primarily via T helper (Th) 2- and Th17-derived cytokines, many of which are mediated by the Janus kinase (JAK) signaling pathway. These local inflammatory processes interact with sensory neuronal pathways, contributing to the clinical manifestations of AD, including itch, pain, and sleep disturbance. The recent elucidation of the molecular pathways involved in AD has allowed treatment strategies to evolve from broad-acting systemic immunosuppressive therapies to more targeted agents, including JAK inhibitors and cytokine-specific biologic agents. Evidence from the clinical development of these targeted therapies has reinforced and expanded our understanding of the pathophysiological mechanisms underlying AD and holds promise for individualized treatment strategies tailored to specific AD subtypes.

Transcriptome-based identification of novel endotypes in adult atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a frequent and heterogeneous inflammatory skin disease, for which personalized medicine remains a challenge. High-throughput approaches have improved understanding of the complex pathophysiology of AD. However, a purely data-driven AD classification is still lacking.

METHODS

To address this question, we applied an original unsupervised approach on the largest available transcriptome dataset of AD lesional (n = 82) and healthy (n = 213) skin biopsies.

RESULTS

Taking into account pathological and physiological state, a variance-based filtering revealed 222 AD-specific hyper-variable genes that efficiently classified the AD samples into 4 clusters that turned out to be clinically and biologically distinct. Comparison of gene expressions between clusters identified 3 sets of upregulated genes used to derive metagenes (MGs): MG-I (19 genes) was associated with IL-1 family signaling (including IL-36A and 36G) and skin remodeling, MG-II (23 genes) with negative immune regulation (including IL-34 and 37) and skin architecture, and MG-III (17 genes) with B lymphocyte immunity. Sample clusters differed in terms of disease severity (p = .02) and S. aureus (SA) colonization (p = .02). Cluster 1 contained the most severe AD, highest SA colonization, and overexpressed MG-I. Cluster 2 was characterized by less severe AD, low SA colonization, and high MG-II expression. Cluster 3 included mild AD, mild SA colonization, and mild expression of all MGs. Cluster 4 had the same clinical features as cluster 3 but had hyper-expression of MG-III. Last, we successfully validated our method and results in an independent cohort.

CONCLUSION

Our study revealed unrecognized AD endotypes with specific underlying biological pathways, highlighting novel pathophysiological mechanisms. These data could provide new insights into personalized treatment strategies.

The Atopic Dermatitis Control Tool: A High-Performance Tool for Optimal Support

The evaluation of global atopic dermatitis control is key to minimizing disease burden. The Atopic Dermatitis Control Tool (ADCT) has been developed for this purpose. Participants (diagnosed by a physician) were recruited to this observational cross-sectional study using real-life methodology and completed a questionnaire on sociodemographic and personal information. The ADCT algorithm, described by Pariser, was used to categorize patients as having controlled or uncontrolled atopic dermatitis. Data were collected for 1,606 patients. Median age of the patients was 40 years , and 1,023 (63.7%) patients were women. A total of 1,146 (71.4%) patients had uncontrolled atopic dermatitis according to the ADCT score. Patients with uncontrolled disease were at significantly higher risk of a high stress level and were more likely to be absent from work than those with controlled disease. In conclusion, a key factor for predicting disease burden in atopic dermatitis is patient self-assessed disease control in terms of multiple dimensions: stress, sleep, quality of life, work absenteeism and loss of productivity.

Proteomic signatures of inflammatory skin diseases: a focus on atopic dermatitis

Introduction: Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by cutaneous and systemic inflammation and barrier abnormalities. Over the past few decades, proteomic studies have been increasingly applied to AD research to compliment transcriptomic evaluations. Proteomic analyses helped identify new biomarkers of AD, allowing investigation of both the cutaneous AD profile and the systemic inflammation associated with the disease.Areas covered: This review discusses key studies that utilized various proteomic technologies to analyze AD skin and/or blood, which facilitated discovery of biomarkers related to pathogenesis, disease severity, systemic inflammation, and therapeutic response. Moreover, this review summarizes proteomic studies that helped define various AD endotypes/phenotypes. A literature search was conducted by querying Scopus, Google Scholar, PubMed/Medline, and Clinicaltrials.gov up to January 2021.Expert opinion: Use of proteomics in AD has allowed for identification of novel AD-related protein biomarkers. This approach continues to evolve and is becoming increasingly common for the study of AD, in conjunction with other -omics platforms, as proteomics shifts to quicker and more sensitive methods for detection of potential protein biomarkers. Although many biomarkers have been identified thus far, future larger studies are necessary to further correlate these markers with clinical parameters.

Insights into adult atopic dermatitis heterogeneity derived from circulating biomarker profiling in patients with moderate-to-severe disease

Atopic dermatitis (AD) is a heterogeneous systemic inflammatory skin disease associated with dysregulated immune responses, barrier dysfunction and activated sensory nerves. To characterize circulating inflammatory profiles and underlying systemic disease heterogeneity within AD patients, blood samples from adult patients (N = 123) with moderate‐to‐severe AD in a phase 2 study of baricitinib (JAHG) were analysed. Baseline levels of 131 markers were evaluated using high‐throughput and ultrasensitive proteomic platforms, patient clusters were generated based on these peripheral markers. We implemented a novel cluster reproducibility method to validate cluster outcomes within our study and used publicly available AD biomarker data set (73 markers, N = 58 patients) to validate our findings. Cluster reproducibility analysis demonstrated best consistency for 2 clusters by k‐means, reproducibility of this clustering outcome was validated in an independent patient cohort. These unique JAHG patient subgroups either possessed elevated pro‐inflammatory mediators, notably TNFβ, MCP‐3 and IL‐13, among a variety of immune responses (high inflammatory) or lower levels of inflammatory biomarkers (low inflammatory). The high inflammatory subgroup was associated with greater baseline disease severity, demonstrated by greater EASI, SCORAD Index, Itch NRS and DLQI scores, compared with low inflammatory subgroup. African‐American patients were predominantly associated with the high inflammatory subgroup and increased baseline disease severity. In patients with moderate‐to‐severe AD, heterogeneity was identified by the detection of 2 disease subgroups, differential clustering amongst ethnic groups and elevated pro‐inflammatory mediators extending beyond traditional polarized immune responses. Therapeutic strategies targeting multiple pro‐inflammatory cytokines may be needed to address this heterogeneity.

Keratinocytes: innate immune cells in atopic dermatitis

The skin is a unique immune organ that constitutes a complex network of physical, chemical and microbiological barriers against external insults. Keratinocytes are the most abundant cell type in the epidermis. These cells form the physical skin barrier and represent the first line of the host defense system by sensing pathogens via innate immune receptors, initiating anti-microbial responses and producing various cytokines, chemokines and anti-microbial peptides, which are important events in immunity. A damaged epidermal barrier in atopic dermatitis allows the penetration of potential allergens and pathogens to activate keratinocytes. Among the dysregulation of immune responses in atopic dermatitis, activated keratinocytes play a role in several biological processes that contribute to the pathogenesis of atopic dermatitis. In this review, we summarize the current understanding of the innate immune functions of keratinocytes in the pathogenesis of atopic dermatitis, with a special emphasis on skin-derived anti-microbial peptides and atopic dermatitis-related cytokines and chemokines in keratinocytes. An improved understanding of the innate immunity mediated by keratinocytes can provide helpful insight into the pathophysiological processes of atopic dermatitis and support new therapeutic efforts.

Higher prevalence of seizure activity in a small population of atopic dogs: a retrospective breed- and age-matched study

BACKGROUND

Atopic dermatitis (AD) is considered to be a systemic disease in people shown to have an association with epilepsy. However, so far, no data about the association of epilepsy and atopy have been reported in dogs.

OBJECTIVES

Given the homology between human and canine AD, and the increased incidence of epilepsy in atopic people, we investigated the association between AD and seizure-associated activity in a small canine population.

ANIMALS

We included 34 atopic dogs and 34 breed- and age range-matched nonatopic dogs.

METHODS AND MATERIALS

We investigated the association between canine AD and signs of seizures in a retrospective, breed- and age range-matched, case-controlled study. Dog owners were interviewed using a standardized questionnaire. The presence or absence of signs of seizure activity and possible comorbidities were questioned.

RESULTS

Seven of the 34 atopic dogs also suffered from seizure activity. By contrast, only one dog affected with seizure signs could be identified among the 34 nonatopic dogs. Atopic dermatitis was associated with a higher frequency of seizure activity (McNemar test, P = 0.035; one-sided) and atopic dogs had a higher odds ratio to develop seizures [(95% CI) 7 (0.9-56.9)] compared to the age- and breed-matched nonatopic control group. No other comorbidities were detected.

CONCLUSION AND CLINICAL IMPORTANCE

In our small retrospective study, we observed an increased prevalence of seizure activity in the atopic dog population. Further larger and prospective studies are needed to confirm these results.

Normal insulin sensitivity, glucose tolerance, gut incretin and pancreatic hormone responses in adults with atopic dermatitis

AIM

To examine whether adults with mild to moderate atopic dermatitis (AD) had reduced insulin sensitivity and/or exhibited other gluco-metabolic disturbances compared with carefully matched healthy controls.

MATERIALS AND METHODS

Sixteen adult, non-obese, non-diabetic patients with mild to moderate AD and 16 gender-, age- and body mass index (BMI)-matched healthy controls underwent a hyperinsulinaemic euglycaemic clamp (insulin infusion rate: 40 mU/m² /minute) and an oral glucose tolerance test (OGTT) with frequent blood sampling for gut and pancreatic hormones.

RESULTS

The two groups were similar in age (33 ± 3 vs. 33 ± 3 years, mean ± standard error of the mean [SEM]), gender (56% women), BMI (24.5 ± 0.7 vs. 24.4 ± 0.7 kg/m² ), physical activity level, fasting plasma glucose and HbA1c. Patients with AD had a mean Eczema Area and Severity Index score of 8.5 ± 1.0 (moderate disease) and a mean AD duration of 28 ± 3 years. During the OGTT, circulating glucose, insulin, C-peptide, glucagon and glucose-dependent insulinotropic polypeptide, respectively, were similar in the two groups, except glucagon-like peptide-1, which was higher in patients with AD. The clamp showed no differences in insulin sensitivity between groups (M-value 9.2 ± 0.6 vs. 9.8 ± 0.8, P = .541, 95% CI -1.51; 2.60), or circulating insulin, C-peptide and glucagon levels.

CONCLUSIONS

Using OGTT and the hyperinsulinaemic euglycaemic clamp technique, we found no difference in insulin sensitivity or other gluco-metabolic characteristics between patients with mild to moderate AD and matched healthy controls, suggesting that the inflammatory skin disease AD has little or no influence on glucose metabolism.

Atopic dermatitis microbiomes stratify into ecologic dermotypes enabling microbial virulence and disease severity

BACKGROUND

Atopic dermatitis (AD) is a common skin disease affecting up to 20% of the global population, with significant clinical heterogeneity and limited information about molecular subtypes and actionable biomarkers. Although alterations in the skin microbiome have been described in subjects with AD during progression to flare state, the prognostic value of baseline microbiome configurations has not been explored.

OBJECTIVE

Our aim was to identify microbial signatures on AD skin that are predictive of disease fate.

METHODS

Nonlesional skin of patients with AD and healthy control subjects were sampled at 2 time points separated by at least 4 weeks. Using whole metagenome analysis of skin microbiomes of patients with AD and control subjects (n = 49 and 189 samples), we identified distinct microbiome configurations (dermotypes A and B). Blood was collected for immunophenotyping, and skin surface samples were analyzed for correlations with natural moisturizing factors and antimicrobial peptides.

RESULTS

Dermotypes were robust and validated across 2 additional cohorts (63 individuals), with strong enrichment of subjects with AD in dermotype B. Dermotype B was characterized by reduced microbial richness, depletion of Cutibacterium acnes, Dermacoccus and Methylobacterium species, individual-specific outlier abundance of Staphylococcus species (eg, S epidermidis, S capitis, S aureus), and enrichment in metabolic pathways (eg, branched chain amino acids and arginine biosynthesis) and virulence genes (eg, β-toxin, δ-toxin) that defined a pathogenic ecology. Skin surface and circulating host biomarkers exhibited a distinct microbial-associated signature that was further reflected in more severe itching, frequent flares, and increased disease severity in patients harboring the dermotype B microbiome.

CONCLUSION

We report distinct clusters of microbial profiles that delineate the role of microbiome configurations in AD heterogeneity, highlight a mechanism for ongoing inflammation, and provide prognostic utility toward microbiome-based disease stratification.

Cross-sectional study of blood biomarkers of patients with moderate to severe alopecia areata reveals systemic immune and cardiovascular biomarker dysregulation

BACKGROUND

Although there is increased understanding of the alopecia areata (AA) pathogenesis based on studies in scalp tissues, little is known about its systemic profile.

OBJECTIVE

To evaluate the blood proteomic signature of AA and determine biomarkers associated with increased disease severity.

METHODS

In a cross-sectional study, we assessed 350 inflammatory and cardiovascular proteins using OLINK high-throughput proteomics in patients with moderate to severe AA (n = 35), as compared with healthy individuals (n = 36), patients with moderate to severe psoriasis (n = 19), and those with atopic dermatitis (n = 49).

RESULTS

Seventy-four proteins were significantly differentially expressed between AA and control individuals (false discovery rate, <.05) including innate immunity (interleukin [IL] 6/IL-8), T helper (Th) type 1 (interferon [IFN] γ/CXCL9/CXCL10/CXCL11), Th2 (CCL13/CCL17/CCL7), Th17 (CCL20/PI3/S100A12), and cardiovascular-risk proteins (OLR1/OSM/MPO/PRTN3). Eighty-six biomarkers correlated with AA clinical severity (P < .05), including Th1/Th2, and cardiovascular/atherosclerosis-related proteins, including SELP/PGLYRP1/MPO/IL-18/OSM (P < .05). Patients with AA totalis/universalis showed the highest systemic inflammatory tone, including cardiovascular risk biomarkers, compared to control individuals and even to patients with atopic dermatitis and those with psoriasis. The AA profile showed some Th1/Th2 differences in the setting of concomitant atopy.

LIMITATIONS

Our analysis was limited to 350 proteins.

CONCLUSION

This study defined the abnormalities of moderate to severe AA and associated circulatory biomarkers. It shows that AA has systemic immune, cardiovascular, and atherosclerosis biomarker dysregulation, suggesting the need for systemic treatment approaches.

3'-Sialyllactose prebiotics prevents skin inflammation via regulatory T cell differentiation in atopic dermatitis mouse models

3'-Sialyllactose (3'-SL), a natural prebiotic, maintains immune homeostasis and exerts anti-inflammatory and anti-arthritic effects. Although regulatory T cells (Tregs) prevent excessive inflammation and maintain immune tolerance, the effect of 3'-SL on Treg regulation is unclear. This study aimed to investigate the effect of 3'-SL on Treg responses in atopic dermatitis (AD) pathogenesis. Oral administration of 3'-SL reduced AD-like symptoms such as ear, epidermal, and dermal thickness in repeated topical application of house dust mites (HDM) and 2,4-dinitrochlorobenzene (DNCB). 3'-SL inhibited IgE, IL-1β, IL-6, and TNF-α secretion and markedly downregulated AD-related cytokines including IL-4, IL-5, IL-6, IL-13, IL-17, IFN-γ, TNF-α, and Tslp through regulation of NF-κB in ear tissue. Additionally, in vitro assessment of Treg differentiation revealed that 3'-SL directly induced TGF-β-mediated Treg differentiation. Furthermore, 3'-SL administration also ameliorated sensitization and elicitation of AD pathogenesis by suppressing mast cell infiltration and production of IgE and pro-inflammatory cytokines in mouse serum by mediating the Treg response. Furthermore, Bifidobacterium population was also increased by 3'-SL administration as prebiotics. Our data collectively show that 3'-SL has therapeutic effects against AD progression by inducing Treg differentiation, downregulating AD-related cytokines, and increasing the Bifidobacterium population.

Evaluating patient-perceived control of atopic dermatitis: design, validation, and scoring of the Atopic Dermatitis Control Tool (ADCT)

Objectives: The Atopic Dermatitis Control Tool (ADCT) was designed to evaluate patient-perceived AD control and facilitate patient-physician discussion on long-term disease control.Methods: The study was performed in adult patients with AD. Development of the ADCT followed US Food and Drug Administration (FDA) guidelines on patient-reported outcome measures (PROMs). Qualitative research, including targeted literature review, interviews with clinical experts, and combined concept elicitation/cognitive debriefing with patients with AD, was conducted to provide a list of comprehensive concepts capturing AD control per physician and patient perspectives. Quantitative methods assessed psychometric properties of the instrument and defined the threshold for AD control.Results: The resulting pilot six-item ADCT, reflecting key concepts related to AD control, had 7-day recall and assessed symptoms and impacts on patients' everyday lives by severity and/or frequency. The ADCT showed good content validity (well understood by adult patients with AD), and quick completion time (<2 min). Psychometric analysis indicated no floor/ceiling effects for response distributions, particularly strong (r ≥ 0.80) inter-item correlations for the six ADCT items, robust construct validity (r > 0.50), and item-level discriminating ability (p < .03); this supported the derivation of a total score based on responses to all items. ADCT total score showed evidence of strong internal consistency reliability (Cronbach's alpha >0.80). A score ≥7 points was identified as an optimum threshold to identify patients whose AD is "not in control."Conclusions: No single validated instrument has been available to holistically evaluate patient-perceived AD control. The newly developed ADCT displays good-to-excellent content validity, construct validity, internal consistency, reliability, and discriminating ability.

The patient-reported disease burden in adults with atopic dermatitis: a cross-sectional study in Europe and Canada

Background

Cross‐sectional data on patient burden in adults with atopic dermatitis (AD) from real‐world clinical practice are limited.

Objective

This study compared patient‐reported burden associated with adult AD across severity levels from clinical practices in Canada and Europe.

Methods

This study included adults (18–65 years) diagnosed with AD by dermatologists, general practitioners or allergists. Participants categorized as mild (n = 547; 37.3%), moderate (n = 520; 35.4%) or severe (n = 400; 27.3%) based on Investigator's Global Assessment completed a questionnaire that included pruritus and pain numerical rating scales, Patient‐Oriented‐Scoring of Atopic Dermatitis (PO‐SCORAD) itch and sleep visual analogue scales, Dermatology Life Quality Index (DLQI), and the Hospital Anxiety and Depression Scale (HADS). Participants were also stratified by inadequate efficacy/intolerance/contraindication to cyclosporine [Cyclo; n = 62 (4 mild, 18 moderate, 40 severe)] and any systemic immunomodulatory agent [IMM; n = 104 (13 mild, 31 moderate, 60 severe)] and compared with the severe group excluding participants identified as Cyclo/IMM.

Results

Age was similar across severity groups; the proportion of women was higher in the mild group relative to severe (61.2% vs. 50.5%; P < 0.001). Compared with moderate and mild, participants with severe AD had more comorbidities, higher itch and pain severity, worse sleep and higher levels of anxiety and depression (all P < 0.001). Mean ± SD DLQI score among participants with severe AD (16.2 ± 6.9) showed a large effect on quality of life that was higher than those with moderate (10.2 ± 6.3) and mild (5.5 ± 4.9) (both P < 0.001). The burden among Cyclo and IMM subgroups was generally similar to that of participants with severe AD.

Conclusions

Adults with AD reported a substantial burden across multiple domains that was significantly higher in those with severe disease. The burden among participants in the Cyclo/IMM subgroups was similar to those with severe AD.

Validation of the Atopic Dermatitis Control Tool (ADCT©) using a longitudinal survey of biologic-treated patients with atopic dermatitis

BACKGROUND

The Atopic Dermatitis Control Tool (ADCT©) is a brief patient self-administered instrument designed and validated to assess atopic dermatitis (AD) control; six AD symptoms and impacts are evaluated over the past week, including overall severity of symptoms, days with intense episodes of itching, intensity of bother, problem with sleep, impact on daily activities, and impact on mood or emotions. This study assessed the reliability, validity, and responsiveness of the ADCT in a longitudinal context, and provided thresholds to identify meaningful within-person change.

METHODS

Data were from a prospective, longitudinal patient survey study of real-world effectiveness of dupilumab in patients with AD. Eligible patients completed a baseline survey before starting dupilumab and were followed at Months 1, 2, 3, and 6 post-initiation as they became eligible.

RESULTS

Psychometric analyses confirmed internal consistency; Cronbach's α coefficients were consistently above the threshold of 0.70 across each follow-up; item-to-total correlations were above the threshold of r ≥ 0.50. High correlations between the ADCT and the Dermatology Life Quality Index (DLQI) and skin pain supported construct validity, while known-group validity was shown on Patient Global Assessment of Disease (PGAD) overall well-being subgroups with worse AD-related overall well-being having higher mean ADCT total scores at all time points. The ability of the ADCT to detect change was confirmed; the threshold for meaningful within-person change was estimated to be 5 points. Finally, test-retest reliability was confirmed in subgroups of patients with stable PGAD responses.

CONCLUSIONS

Our findings confirm that the ADCT is a valid and reliable tool for assessing AD control.

Evolution of pathologic T-cell subsets in patients with atopic dermatitis from infancy to adulthood

BACKGROUND

The circulating immune phenotype was defined in adults and young children with early atopic dermatitis (AD), but chronologic changes in the blood of infants and children with AD through adolescence have not been explored.

OBJECTIVE

We sought to compare immune activation and cytokine polarization in the blood of 0- to 5-year-old (n = 39), 6- to 11-year-old (n = 26), 12- to 17-year-old (n = 21) and 18-year-old or older (n = 43) patients with AD versus age-matched control subjects.

METHODS

Flow cytometry was used to measure IFN-γ, IL-9, IL-13, IL-17, and IL-22 cytokine levels in CD4⁺/CD8⁺ T cells, with inducible costimulator molecule and HLA-DR defining midterm and long-term T-cell activation, respectively, within skin-homing/cutaneous lymphocyte antigen (CLA)⁺ versus systemic/CLA^- T cells. Unsupervised clustering differentiated patients based on their blood biomarker frequencies.

RESULTS

Although CLA⁺ T_H1 frequencies were significantly lower in infants with AD versus all older patients (P < .01), frequencies of CLA⁺ T_H2 T cells were similarly expanded across all AD age groups compared with control subjects (P < .05). After infancy, CLA^- T_H2 frequencies were increased in patients with AD in all age groups, suggesting systemic immune activation with disease chronicity. IL-22 frequencies serially increased from normal levels in infants to highly significant levels in adolescents and adults compared with levels in respective control subjects (P < .01). Unsupervised clustering aligned the AD profiles along an age-related spectrum from infancy to adulthood (eg, inducible costimulator molecule and IL-22).

CONCLUSIONS

The adult AD phenotype is achieved only in adulthood. Unique cytokine signatures characterizing individual pediatric endotypes might require age-specific therapies. Future longitudinal studies, comparing the profile of patients with cleared versus persistent pediatric AD, might define age-specific changes that predict AD clearance.

Increased cardiovascular and atherosclerosis markers in blood of older patients with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is associated with increased systemic inflammation and cardiovascular risk. Although previous studies have found increased inflammatory proteins in the blood of patients with AD, detailed comparison among patients with AD of different ages is unavailable.

OBJECTIVE

To characterize the blood proteomic signature of patients with AD as a function of age.

METHODS

We used the OLINK high-throughput proteomic assay to measure serum inflammatory and cardiovascular risk proteins in 71 patients with moderate to severe AD from 3 age groups (18-40 years old [n = 26], 41-60 years old [n = 24], and >60 years old [n = 21]) compared with 37 age-matched controls. Total and allergen-specific serum IgEs were also measured.

RESULTS

When we compared patients with AD from 3 different age groups with their respective controls, we identified a total of 172 differentially expressed proteins. T_H2 chemokines (CCL13, CCL17) were consistently elevated in patients with AD across all ages (P < .05), whereas T_H1 (CXCL10) and T_H17 (KYNU, CCL20) markers incrementally increased with age in both patients with AD and healthy subjects. Elderly patients with AD (>60 years old) exhibited striking upregulation of key proinflammatory proteins, including markers of atherosclerosis (CCL4, CCL7, SORT1), cardiovascular risk (GDF15, MPO, ST2), cell adhesion (CDH3), and apoptosis (FAS; all P < .05) compared with younger patients with AD and age-matched controls. We also found that total and allergen-specific serum IgEs decreased significantly with age in patients with AD (P < .05).

CONCLUSION

Elderly patients with AD had increased levels of systemic inflammatory markers, including those associated with cardiovascular and atherosclerosis risk, which may explain their increased incidence of cardiovascular disease. This finding suggests that older patients with AD may benefit from cardiovascular disease screening and prevention.

Understanding the immune landscape in atopic dermatitis: The era of biologics and emerging therapeutic approaches

Atopic dermatitis (AD) is a chronic, systemic, inflammatory disease that affects the skin and is characterized by persistent itch and marked redness. AD is associated with an increased risk of skin infections and a reduced quality of life. Most AD treatment options to date were not designed to selectively target disease-causing pathways that have been established for this indication. Topical therapies have limited efficacy in moderate-to-severe disease, and systemic agents such as corticosteroids and immunosuppressants present with tolerability issues. Advances in the understanding of AD pathobiology have made possible a new generation of more disease-specific AD therapies. AD is characterized by the inappropriate activation of type 2 T helper (Th2) cells and type 2 innate lymphoid (ILC2) cells, with a predominant increase in type 2 cytokines in the skin, including interleukin (IL)-13 and IL-4. Both cytokines are implicated in tissue inflammation and epidermal barrier dysfunction, and monoclonal antibodies targeting each of these interleukins or their receptors are in clinical development in AD. In March 2017, dupilumab, a human anti-IL-4Rα antibody, became the first biologic to receive approval in the United States for the treatment of moderate-to-severe AD. The anti-IL-13 monoclonal antibodies lebrikizumab and tralokinumab, which bind different IL-13 epitopes with potentially different effects, are currently in advanced-stage trials. Here, we briefly review the underlying pathobiology of AD, the scientific basis for current AD targets, and summarize current clinical studies of these agents, including new research to develop both predictive and response biomarkers to further advance AD therapy in the era of precision medicine.

Personalized medicine-concepts, technologies, and applications in inflammatory skin diseases

The current state, tools, and applications of personalized medicine with special emphasis on inflammatory skin diseases like psoriasis and atopic dermatitis are discussed. Inflammatory pathways are outlined as well as potential targets for monoclonal antibodies and small-molecule inhibitors.

Distinct transcriptomic profiles of early-onset atopic dermatitis in blood and skin of pediatric patients

BACKGROUND

Atopic dermatitis (AD) predominantly affects young children, but our understanding of AD pathogenesis is based on skin and blood samples from long-standing adult AD. Genomic biopsy profiling from early pediatric AD showed significant Th2 and Th17/Th22-skewing, without the characteristic adult Th1 up-regulation. Because obtaining pediatric biopsies is difficult, blood gene expression profiling may provide a surrogate for the pediatric skin signature.

OBJECTIVE

To define the blood profile and associated biomarkers of early moderate-to-severe pediatric AD.

METHODS

We compared microarrays and reverse transcription polymerase chain reaction (RT-PCR) of blood cells from 28 AD children (<5 years and within 6 months of disease onset) to healthy control blood cells. Differentially expressed genes (DEGs) in blood (fold change [FCH] > 1.2 and false discovery rate [FDR] < 0.05) were then compared with skin DEGs.

RESULTS

Eosinophil and Th2 markers (IL5RA, IL1RL1/ST2, HRH4, CCR3, SIGLEC8, PRSS33, CLC from gene arrays; IL13/IL4/CCL22 from RT-PCR) were up-regulated in early pediatric AD blood, whereas IFNG/Th1 was decreased. Th1 markers were negatively correlated with clinical severity (EASI, pruritus, transepidermal water loss [TEWL]), whereas Th2/Th17-induced interleukin (IL)-19 was positively correlated with SCORAD. Although a few RT-PCR-defined immune markers (IL-13/CCL22) were increased in blood, as previously also reported for skin, minimal overlap based on gene array DEGs was seen.

CONCLUSION

The whole blood signature of early moderate-to-severe pediatric AD blood cells show predominantly a Th2/eosinophil profile; however, markers largely differ from the skin profile. Given their complementarity, pooling of biomarkers from blood and skin may improve profiling and predictions, providing insight regarding disease course, allergic comorbidity development, and response to systemic medications.

Major Comorbidities of Atopic Dermatitis: Beyond Allergic Disorders

The consequences of atopic dermatitis reach beyond the skin and past childhood. Patients with atopic dermatitis are at risk of developing allergic comorbidities, but less is known about the associations between atopic dermatitis and non-allergic conditions. Understanding these non-allergic comorbidities has the potential to improve patient outcomes and to help mitigate the cost and burdens associated with these conditions. Atopic dermatitis is associated with cutaneous bacterial infections, more severe forms/courses of cutaneous viral infections, and extra-cutaneous infections. Atopic dermatitis is also associated with several mental health comorbidities particularly attention-deficit hyperactivity disorder, anxiety, and depression. Data are largely inconsistent for specific cancers, but atopic dermatitis appears to protect against malignancy overall; severe long-term atopic dermatitis is associated with adult lymphomas. Atopic dermatitis may also be associated with obesity, cardiovascular disease, and autoimmune disease, particularly alopecia areata and gastrointestinal immune-mediated disorders. Although the causative mechanisms underlying these associations are poorly understood, treating physicians should be aware of associations in seeking to alleviate the burden for patients with atopic dermatitis.