A mild topical steroid leads to progressive anti-inflammatory effects in the skin of patients with moderate-to-severe atopic dermatitis

Dissolving microneedle patch loaded with adipokines-enriched adipose extract relieves atopic dermatitis in mouse via modulating immune disorders, microbiota imbalance, and skin barrier defects

Atopic dermatitis (AD) is a chronic relapsing dermatosis that demands new therapies. This research group previously developed a physically extracted adipose-derived extracellular matrix named adipose collagen fragments (ACF), which was determined containing massive adipose matrix-bound adipokines and medicable on AD through intradermal injection. However, problems concerning the control of drug release and inevitable pain caused by injection hinder the application of ACF in clinics. Microneedle (MN) is a rapid developing technique for precise and painless transdermal drug delivery. Therefore, a dissolving methacrylated gelatin/hyaluronic acid MN patch loaded with ACF was developed in this study. The morphological characteristics, mechanical properties, penetration ability, as well as biocompatibility and degradation efficiency of ACF-MN were evaluated, and its efficacy on ovalbumin-induced AD mice was also investigated. ACF-MN exhibited excellent penetration ability, biocompatibility, degradation efficiency, and satisfying efficacy on murine AD similar with fresh-made ACF. Furthermore, RNA-Seq combining bioinformatics were performed for mechanism exploration. ACF treatment showed a comprehensive efficacy on AD via restoring inflammatory dysregulation, microbiota imbalance, and skin barrier defects. This study offered a novel MN-based ACF-bound adipokines transdermal delivery system that may serve as a promising strategy for relieving AD.

Special Considerations in Atopic Dermatitis in Young Children

Atopic dermatitis (AD) begins in early childhood in the majority of children. Addressing AD in small children includes recognition of the early presentations of disease in all skin types, triggers, comorbidities, and therapeutics. These include risk of medication absorption, more xerosis, infections, and creating management plans that are acceptable to parents/caregivers, while offering safety. Vaccination efficacy, safety on systemic agents, growth and development, tactile sensory development, and teething-related facial eruptions of early childhood are additional concerns. Prevention of long-term comorbidities is the highest goal. Using age-based considerations helps support excellence in care and improved patient-parent experience.

Mapping the Periostin splice isoforms in atopic dermatitis and an in vitro asthma model - A multi-platform analysis using mass spectrometry and RT-qPCR

Periostin is a matricellular protein known to be alternatively spliced to produce ten isoforms with a molecular weight of 78-91 kDa. Within the extracellular matrix, periostin attaches to cell surfaces to induce signaling via integrin-binding and actively participates in fibrillogenesis, orchestrating the arrangement of collagen in the extracellular environment. In atopic diseases such as atopic dermatitis (AD) and asthma, periostin is known to participate in driving the disease-causing type 2 inflammation. The periostin isoforms expressed in these diseases and the implication of the alternative splicing events are unknown. Here, we present two universal assays to map the expression of periostin isoforms at the mRNA (RT-qPCR) and protein (PRM-based mass spectrometry) levels. We use these assays to study the splicing profile of periostin in AD lesions as well as in in vitro models of AD and asthma. In these conditions, periostin displayed overexpression with isoforms 3 and 5 standing out as highly overexpressed. Notably, isoforms 9 and 10 exhibited a divergent pattern relative to the remaining isoforms. Isoforms 9 and 10 are often overlooked in periostin research and this paper presents the first evidence of their expression at the protein level. This underlines the necessity to include isoforms 9 and 10 in future research addressing periostin splice isoforms. The assays presented in this paper hold the potential to improve our insight into the splicing profile of periostin in tissues and diseases of interest. The application of these assays to AD lesions and in vitro models demonstrated their potential for identifying isoforms of particular significance, warranting a further in-depth investigation.

Atopic dermatitis: Pathophysiology, microbiota, and metabolome - A comprehensive review

Atopic dermatitis (AD) is a prevalent inflammatory skin condition that commonly occurs in children. Genetics, environment, and defects in the skin barrier are only a few of the factors that influence how the disease develops. As human microbiota research has advanced, more scientific evidence has shown the critical involvement of the gut and skin bacteria in the pathogenesis of atopic dermatitis. Microbiome dysbiosis, defined by changed diversity and composition, as well as the development of pathobionts, has been identified as a potential cause for recurring episodes of atopic dermatitis. Gut dysbiosis causes "leaky gut syndrome" by disrupting the epithelial lining of the gut, which allows bacteria and other endotoxins to enter the bloodstream and cause inflammation. The same is true for the disruption of cutaneous homeostasis caused by skin dysbiosis, which enables bacteria and other pathogens to reach deeper skin layers or even systemic circulation, resulting in inflammation. Furthermore, it is now recognized that the gut and skin microbiota releases both beneficial and toxic metabolites. Here, this review covers a range of topics related to AD, including its pathophysiology, the microbiota-AD connection, commonly used treatments, and the significance of metabolomics in AD prevention, treatment, and management, recognizing its potential in providing valuable insights into the disease.

Current and Emerging Therapies for Atopic Dermatitis in the Elderly

Atopic dermatitis (AD) in the elderly has recently emerged as a distinct subgroup of AD, garnering widespread concern due to its increasing global incidence rate. Epidermal barrier dysfunction, inflammatory response, and chronic pruritus interact with each other, contributing to the pathogenesis and pathophysiology of AD in the elderly. Although fundamental medications are essential for managing AD in the elderly, older adults often struggle with regular usage of moisturizing emollients, topical medications, and avoidance of environmental triggers, leading to recurrent or even exacerbated disease progression. Therefore, a systematic medication approach is necessary to control pruritus and skin lesions. Traditional systemic treatments may not adequately meet the treatment needs of moderate and severe AD in the elderly and may even pose certain safety risks. Biologics and Janus kinase (JAK) inhibitors, exhibiting excellent clinical efficacy, have made significant breakthroughs in AD treatment. Existing evidence suggests that dupilumab, a human monoclonal IgG4 antibody, has been confirmed as an effective and safe first-line systematic treatment for moderate to severe AD in the elderly, with no notable differences between adults and the elderly. However, the limited inclusion of elderly patients in related clinical studies hinders the generalizability of these findings. As older patients face a higher risk of adverse events with JAK inhibitors, JAK inhibitors are recommended when no other suitable treatment options are available. Obtaining population-specific data is crucial for making evidence-based treatment choices when managing AD in older adults with JAK inhibitors.

CKBA suppresses mast cell activation via ERK signaling pathway in murine atopic dermatitis

Atopic dermatitis (AD) is a common inflammatory skin disorder. Mast cells play an important role in AD because they regulate allergic reactions and inflammatory responses. However, whether and how the modulation of mast cell activity affects AD has not been determined. In this study, we aimed to determine the effects and mechanisms of 3-O-cyclohexanecarbonyl-11-keto-β-boswellic acid (CKBA). This natural compound derivative alleviates skin inflammation by inhibiting mast cell activation and maintaining skin barrier homeostasis in AD. CKBA markedly reduced serum IgE levels and alleviated skin inflammation in calcipotriol (MC903)-induced AD mouse model. CKBA also restrained mast cell degranulation both in vitro and in vivo. RNA-seq analysis revealed that CKBA downregulated the extracellular signal-regulated kinase (ERK) signaling in BM-derived mast cells activated by anti-2,4-dinitrophenol/2,4-dinitrophenol-human serum albumin. We proved that CKBA suppressed mast cell activation via ERK signaling using the ERK activator (t-butyl hydroquinone) and inhibitor (selumetinib; AZD6244) in AD. Thus, CKBA suppressed mast cell activation in AD via the ERK signaling pathway and could be a therapeutic candidate drug for AD.

Genomic Signature in Evolutionary Biology: A Review

Organisms are unique physical entities in which information is stored and continuously processed. The digital nature of DNA sequences enables the construction of a dynamic information reservoir. However, the distinction between the hardware and software components in the information flow is crucial to identify the mechanisms generating specific genomic signatures. In this work, we perform a bibliometric analysis to identify the different purposes of looking for particular patterns in DNA sequences associated with a given phenotype. This study has enabled us to make a conceptual breakdown of the genomic signature and differentiate the leading applications. On the one hand, it refers to gene expression profiling associated with a biological function, which may be shared across taxa. This signature is the focus of study in precision medicine. On the other hand, it also refers to characteristic patterns in species-specific DNA sequences. This interpretation plays a key role in comparative genomics, identifying evolutionary relationships. Looking at the relevant studies in our bibliographic database, we highlight the main factors causing heterogeneities in genome composition and how they can be quantified. All these findings lead us to reformulate some questions relevant to evolutionary biology.

Cellular mechanisms and effects of IL-4 receptor blockade in experimental conjunctivitis evoked by skin inflammation

Ocular surface diseases, including conjunctivitis, are recognized as common comorbidities in atopic dermatitis (AD) and occur at an increased frequency in patients with AD treated with biologics targeting IL-4 receptor α (IL-4Rα) or IL-13. However, the inflammatory mechanisms underlying this pathology are unknown. Here, we developed a potentially novel mouse model of skin inflammation-evoked conjunctivitis and showed that it is dependent on CD4+ T cells and basophils. Blockade of IL-4Rα partially attenuated conjunctivitis development, downregulated basophil activation, and led to a reduction in expression of genes related to type 2 cytokine responses. Together, these data suggest that an IL-4Rα/basophil axis plays a role in the development of murine allergic conjunctivitis. Interestingly, we found a significant augmentation of a number of genes that encode tear proteins and enzymes in anti-IL-4Rα-treated mice, and it may underlie the partial efficacy in this model and may represent candidate mediators of the increased frequency of conjunctivitis following dupilumab in patients with AD.

Periostin activates distinct modules of inflammation and itching downstream of the type 2 inflammation pathway

Atopic dermatitis (AD) is a chronic relapsing skin disease accompanied by recurrent itching. Although type 2 inflammation is dominant in allergic skin inflammation, it is not fully understood how non-type 2 inflammation co-exists with type 2 inflammation or how type 2 inflammation causes itching. We have recently established the FADS mouse, a mouse model of AD. In FADS mice, either genetic disruption or pharmacological inhibition of periostin, a downstream molecule of type 2 inflammation, inhibits NF-κB activation in keratinocytes, leading to downregulating eczema, epidermal hyperplasia, and infiltration of neutrophils, without regulating the enhanced type 2 inflammation. Moreover, inhibition of periostin blocks spontaneous firing of superficial dorsal horn neurons followed by a decrease in scratching behaviors due to itching. Taken together, periostin links NF-κB-mediated inflammation with type 2 inflammation and promotes itching in allergic skin inflammation, suggesting that periostin is a promising therapeutic target for AD.

Comprehensive Phytochemical Profiling of Polyherbal Divya-Kayakalp-Vati and Divya-Kayakalp-Oil and Their Combined Efficacy in Mouse Model of Atopic Dermatitis-Like Inflammation Through Regulation of Cytokines

PURPOSE

Atopic dermatitis (AD) is a chronic inflammatory disease that varies in signs and symptoms in different individuals. General symptoms include dryness of the skin, itching, and development of red to brownish-gray patches. Divya-Kayakalp-Vati (DKV) and -Oil (DKO) are Indian polyherbal compositions prescribed for treating inflammatory skin diseases. In the present study, we evaluated the anti-inflammatory efficacy of DKV and DKO co-treatment (DKV-O) in ameliorating Oxazolone (OXA)-stimulated AD-like inflammation and pro-inflammatory cytokine release in a Swiss albino mouse model.

METHODS

Phytochemical profiling of the DKV and DKO were done using Liquid Chromatography-Mass Spectroscopy (LC-MS) QToF. Swiss albino mice were sensitized for 7 days and treated with OXA in their ear region. Stimulated and control animals were orally treated with DKV and topically with DKO. Anti-inflammatory efficacy of DKV-O was determined in OXA-treated animals through physiological, histopathological, and biochemical parameter analysis.

RESULTS

DKV and DKO formulations individually contained 39 and 59 phytochemicals, respectively. Many of the phytochemicals have been reported to have anti-inflammatory activities. In the OXA-sensitized Swiss albino mice, combined treatment with DKV-O, and separately with Dexamethasone (positive control) significantly reduced the OXA-stimulated ear edema, biopsy weight, and epidermal thickness. DKV-O further reduced OXA-stimulated induction of inflammatory lesions, neutrophil influx, and release of Interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and myeloperoxidase.

CONCLUSION

Finally, DKV-O co-treatment showed good pharmacological effects in ameliorating AD-like inflammation through the modulation of inflammatory cell influx and release of soluble mediators. Therefore, DKV-O treatment can be used as a suitable polyherbal therapeutic against AD-like inflammatory diseases.

COVID-19 Symptoms Are Attenuated in Moderate-to-Severe Atopic Dermatitis Patients Treated with Dupilumab

Background

In the SARS-CoV-2/COVID-19 pandemic, we need to understand the impact of immunomodulatory medications on COVID-19 symptom severity in patients with inflammatory diseases, including the type 2/Th2 polarized skin disease, atopic dermatitis (AD).

Objective

Because it is believed that type 1/Th1 immunity controls viral infections and that there is a Th1/Th2 counter-regulation, we hypothesized that Th2 targeting with the IL-4Rα-antagonist, dupilumab, in patients with moderate-to-severe AD would rebalance the Th1/Th2 axis, potentially leading to attenuated COVID-19 symptoms.

Methods

A total of 1237 patients with moderate-to-severe AD in the Icahn School of Medicine at Mount Sinai Department of Dermatology were enrolled in a registry. Patients were screened for COVID-19-related symptoms and assigned a severity score (asymptomatic [0]-fatal [5]). Scores were compared among 3 treatment groups: dupilumab (n = 632), other systemic treatments (n = 107), and limited/no treatment (n = 498). Demographic and comorbid covariates were adjusted by multivariate generalized logistic regression models.

Results

The dupilumab-treated group showed reduced incidence and severity of COVID-19 symptoms versus other treatment groups. Dupilumab-treated patients were less likely to experience moderate-to-severe symptoms versus patients on other systemics (P = .01) and on limited/no treatment (P = .04), and less likely to experience any symptoms versus patients on other systemics (P = .01). This effect was seen in our entire cohort and in the subgroup of patients with verified COVID-19 or high-risk exposure.

Conclusions

Patients on dupilumab experienced less severe COVID-19 manifestations and lesser symptoms compared with patients on other systemics and on limited/no treatment. These results suggest that Th2 modulation with dupilumab may have a protective effect on anti-viral immune response in patients with AD.

Pruritus in Keloid Scars: Mechanisms and Treatments

Keloids are scars that extend beyond the margins of an insulting cutaneous injury. Keloids are often thought to be primarily a cosmetic issue, as they are typically quite raised and pigmented. However, these scars also present with functional symptoms of pruritus and pain that significantly impact quality of life. The symptom of pruritus is frequently overlooked by dermatologists, and treatments are often primarily focused on the gross appearance of the scar. This review describes the prevalence and importance of pruritus in keloids. In addition, the putative mechanisms underlying the development of keloid pruritus, which include neuronal and immunological mechanisms, are discussed. Furthermore, this review describes keloid treatments that have been shown to reduce pruritus, treatments that specifically target the itch, and emerging therapies.

Transcriptomic Profiling of Tape-Strips From Moderate to Severe Atopic Dermatitis Patients Treated With Dupilumab

BACKGROUND

Tape-strips are a minimally invasive approach to characterize skin biomarkers in atopic dermatitis (AD). However, they have not yet been used for tracking gene expression changes with systemic treatment.

OBJECTIVE

The aim of the study was to evaluate gene expression changes and therapeutic response biomarkers in AD patients before and after dupilumab (interleukin 4Rα antibody) treatment using tape-strips to obtain epidermal tissue for analysis.

METHODS

Lesional and nonlesional tape-stripped skin was sampled from 18 AD patients before and after dupilumab treatment and from 17 healthy subjects and analyzed by RNA-seq.

RESULTS

At baseline, we detected 6745 and 4859 differentially expressed genes between lesional and nonlesional skin versus normal, respectively, whereas 841 and 977 genes were differentially expressed after treatment, respectively (fold change >1.5 and false discovery rate <0.05). Tape-strips captured significant modulation with dupilumab in key AD immune (eg, C-C motif chemokine ligand 13 [CCL13], CCL17, CCL18) and barrier (eg, periplakin, FA2H) biomarkers. Changes in biomarkers (CCL20, interleukin 34, FABP7) were also significantly correlated with clinical disease improvements (Eczema Area and Severity Index; R > 0.5 or R < -0.4, P < 0.05).

CONCLUSIONS

This real-life study represents the first comprehensive RNA-seq molecular profiling of tape-strips from moderate to severe AD patients after dupilumab therapy. Analysis of tape strip specimens detected significant gene expression changes in key AD biomarkers with dupilumab treatment, suggesting that this approach may be useful to monitor therapeutic responses in inflammatory skin diseases.

Atopic Dermatitis Biomarkers and the Movement Toward Personalized Treatment

Atopic dermatitis (AD) is a heterogeneous disorder with varying phenotypes. Although AD has long been associated with barrier dysfunction, the pathogenesis of this disease is more complex, involving many molecular markers in different functional domains. Biomarkers can be helpful in different ways, including predicting prognosis, measuring treatment response, and gauging disease severity. With the advent of targeted immunomodulators, biomarkers have the potential to take on new significance in terms of selecting appropriate therapies for patients. In this review, we have summarized the key findings related to biomarkers and AD, including the specific subtype differences. Clinicians will use this information to better understand the potential of biomarkers in AD and have a guide because more specific treatments are developed that are tailored toward individual molecular profiles.

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.

Use of Tape Strips to Detect Immune and Barrier Abnormalities in the Skin of Children With Early-Onset Atopic Dermatitis

Importance

Molecular profiling of skin biopsies is the criterion standard for evaluating the cutaneous atopic dermatitis (AD) phenotype. However, skin biopsies are not always feasible in children. A reproducible minimally invasive approach that can track cutaneous disease in pediatric longitudinal studies or clinical trials is lacking.

Objective

To assess a minimally invasive approach using tape strips to identify skin biomarkers that may serve as a surrogate to biomarkers identified using whole-tissue biopsies.

Design, Setting, and Participants

This cross-sectional study of 51 children younger than 5 years recruited children with moderate to severe AD and children without AD from the dermatology outpatient clinics at a children's hospital. Sixteen tape strips were serially collected from the nonlesional and lesional skin of 21 children who had AD and were less than 6 months from disease initiation and from the normal skin of 30 children who did not have AD between January 22, 2016, and April 20, 2018.

Main Outcomes and Measures

Gene and protein expression were evaluated using quantitative real-time polymerase chain reaction and immunohistochemistry.

Results

A total of 51 children younger than 5 years were included in the study; 21 children had moderate to severe AD with less than 6 months of disease duration, and 30 children did not have AD. Of the 21 children with AD, the mean (SD) age was 1.7 (1.7) years, and most were male (15 [71.4%] and white (15 [71.4%]). Of the 30 children without AD, the mean (SD) age was 1.8 (2.0) years, and most were female (20 [66.7%]) and white (22 [73.3%]). Seventy-seven of 79 evaluated immune and barrier gene products were detected (gene detection rate, 97%) in 70 of 71 tape strips (sample detection rate, 99%), with 53 of 79 markers differentiating between children with lesional and/or nonlesional AD from children without AD. Many cellular markers of T cells (CD3), AD-related dendritic cells (Fc ε RI and OX40 ligand receptors), and key inflammatory (matrix metallopeptidase 12), innate (interleukin 8 [IL-8] and IL-6), helper T cell 2 (TH2; IL-4, IL-13, and chemokines CCL17 and CCL26), and TH17/TH22 (IL-19, IL-36G, and S100A proteins) genes were significantly increased in lesional and nonlesional AD compared with tape strips from normal skin. For example, IL-4 mean (SE) for lesional was -15.2 (0.91) and normal was -19.5 (0.48); P < .001. Parallel decreases occurred in epidermal barrier gene products (FLG, CLDN23, and FA2H) and negative immune regulators (IL-34 and IL-37). For example, the decrease for FLG lesional was mean (SE) -2.9 (0.42) and for normal was 2.2 (0.45); P < .001. Associations were found between disease severity or transepidermal water loss and TH2 (IL-33 and IL-4R) and TH17/TH22 (IL-36G and S100As) products in lesional and nonlesional AD skin (evaluated using the SCORing Atopic Dermatitis, Eczema Area and Severity Index, and Pruritus Atopic Dermatitis Quickscore tools).

Conclusions and Relevance

In this study, tape strips provide a minimally invasive alternative for serially evaluating AD-associated cutaneous biomarkers and may prove useful for tracking pediatric AD therapeutic response and predicting future course and comorbidities.

Comparison of Cytokines in Skin Biopsies and Tape Strips from Adults with Atopic Dermatitis

Skin biomarkers for disease severity and treatment response in atopic dermatitis (AD) are needed. Biopsies cause scarring and tape stripping represents an alternative minimally invasive method for stratum corneum sampling. In this study, we examined the gene expression of cytokines in skin biopsies and cytokines in stratum corneum tape strips collected from adults with AD. We collected punch biopsies and tape strips from healthy controls (n = 6) and subjects with AD (n = 12) at baseline and after 2 weeks of topical treatment with mometasone furoate 0.1% cream. We found that IFN-γ, IL-13, and IL-10 mRNA (biopsies) and IL-1β protein expression levels (tape strips) were significantly increased in lesional AD skin compared to healthy control skin. Treatment with topical corticosteroid led to a significant decrease in mRNA levels for IL-13 and IL-4R but no significant differences in cytokine protein levels measured in tape strips. Finally, we found no significant correlations between cytokine levels in tape strips and mRNA levels in skin biopsies.

High-Dose Steroid Dissolving Microneedle for Relieving Atopic Dermatitis

Dissolving microneedles (DMN) supplemented with therapeutic molecules have been developed to enhance transdermal delivery efficiency of topically applied drugs in a minimally invasive manner. However, the dose of the drugs in DMN system is limited owing to the low solubility of drug. In fact, although triamcinolone acetonide (TA) is one of the most widely prescribed drugs for relieving atopic dermatitis (AD), its poor dissolving nature makes it difficult to design and fabricate DMN containing therapeutic dosage of TA. In this study, TA suspension is introduced to encapsulate therapeutic dosage of TA. Sonication and composition optimization of polymers is key to fabricate high dose TA-DMN to induce particle size reduction and dispersion stability of suspension, respectively. After confirming the physical performance of TA-DMN using the selected formulation in vitro, the anti-inflammatory effects of TA-DMN are evaluated in vivo using a mouse model affected with skin inflammation to mimic AD in humans. Herein, high-dose TA-DMN is presented as a candidate agent for relieving AD and, furthermore, for wide application in the treatment of skin inflammatory diseases in which high-dose steroid drugs are required.

Predicting persistence of atopic dermatitis in children using clinical attributes and serum proteins

BACKGROUND

Atopic dermatitis (AD) is the most common inflammatory skin disease in children, with 30% of all those diagnosed developing chronic or relapsing disease by adolescence. Such disease persistence cannot yet be predicted. The aim of the present study was to predict the natural course of AD using clinical parameters and serum proteins.

METHODS

Sera of 144 children with AD (age 0-3 years) were analyzed for IgE and 33 cytokines, chemokines, and growth factors. Patient disease course until the age of 7 years was assessed retrospectively. Unsupervised k-means clustering was performed to define disease endotypes. Identified factors associated with AD persistence at the age of 7 years were validated in children with AD in an independent cohort (LISA Munich; n = 168). Logistic regression and XGBoosting methods followed by cross-validation were applied to predict individual disease outcomes.

RESULTS

Three distinct endotypes were found in infancy, characterized by a unique inflammatory signature. Factors associated with disease persistence were disease score (SCORAD), involvement of the limbs, flexural lesion distribution at the age of 3 years, allergic comorbidities, and disease exacerbation by the trigger factors stress, pollen exposure, and change in weather. Persistence was predicted with a sensitivity of 81.8% and a specificity of 82.4%. Factors with a high impact on the prediction of persistence were SCORAD at the age of 3 years, trigger factors, and low VEGF serum levels.

CONCLUSION

Atopic dermatitis in infancy comprises three immunological endotypes. Disease persistence can be predicted using serum cytokines and clinical variables.

Obesity and ethnicity alter gene expression in skin

Obesity is accompanied by dysfunction of many organs, but effects on the skin have received little attention. We studied differences in epithelial thickness by histology and gene expression by Affymetrix gene arrays and PCR in the skin of 10 obese (BMI 35-50) and 10 normal weight (BMI 18.5-26.9) postmenopausal women paired by age and ethnicity. Epidermal thickness did not differ with obesity but the expression of genes encoding proteins associated with skin blood supply and wound healing were altered. In the obese, many gene expression pathways were broadly downregulated and subdermal fat showed pronounced inflammation. There were no changes in skin microbiota or metabolites. African American subjects differed from European Americans with a trend to increased epidermal thickening. In obese African Americans, compared to obese European Americans, we observed altered gene expression that may explain known differences in water content and stress response. African Americans showed markedly lower expression of the gene encoding the cystic fibrosis transmembrane regulator characteristic of the disease cystic fibrosis. The results from this preliminary study may explain the functional changes found in the skin of obese subjects and African Americans.

Efficacy of biologics in atopic dermatitis

Introduction: Atopic dermatitis (AD) is a heterogeneous disease. Recent advancements in understanding AD pathogenesis resulted in the exponential expansion of its therapeutic pipeline, particularly following the success and FDA-approval of dupilumab. Different phenotypes of AD by age and ethnicity have also recently been described and clinical studies of emerging treatments will further clarify the role of each cytokine pathway in AD.Areas covered: We review the impressive repertoire of biologics for treatment of moderate-to-severe AD, including those targeting Th2, Th22, Th17/IL-23 and IgE. We highlight the scientific rationale behind each approach and provide a discussion of the most recent clinical efficacy and safety data.Expert opinion: AD is a complex disease and recent research has identified numerous endotypes, reinforcing the rationale for developing targeted therapeutics to antagonize these factors. Dupilumab has revolutionized AD treatment and its mechanistic studies also offer crucial insight into AD pathogenesis. Nevertheless, this biologic does not work for everyone, highlighting the need for a more precise approach to address the unique immune fingerprints of each AD subset. Ultimately targeted therapeutics will complement our understanding of the AD molecular map and help push AD management into an era of personalized medicine.

Atopic Dermatitis in Older Adults: A Review of Treatment Options

Atopic dermatitis (AD) in older adults (elderly AD) has recently emerged as a newly defined subgroup of AD. When selecting treatment options, clinical characteristics of elderly AD and age-specific factors of older patients must be considered. As in other age groups, regular application of moisturizers in combination with topical corticosteroids and calcineurin inhibitors, adjunctive administration of oral antihistamines/anti-allergic drugs, and avoidance of exacerbating factors comprise basic treatments for elderly AD. For moderate-to-severe cases and/or in those with a decreased ability to use topical treatments, powerful anti-inflammatory treatments may become necessary as additional treatment options. While low-dose oral corticosteroids may be useful for cases of elderly AD, careful attention should be paid to adverse effects. Oral cyclosporine (ciclosporin) is less commonly used due to the increased risk of malignancy and organ toxicity in older patients with AD. Narrow-band ultraviolet B phototherapy may also be useful for older patients, although the necessity of frequent hospital visits for irradiation therapy may become a burden of disease for such patients. As a biologic, dupilumab therapy markedly improves skin lesions and itch in older patients with AD, with a rapid response and non-serious adverse effects. Nevertheless, injection pain, expensive medical care, and regular follow-up every 2 weeks are disadvantages of dupilumab therapy. Therefore, clinicians must prioritize individualized treatment options that will reduce the burden of disease for cases of elderly AD.

Microbe-host interplay in atopic dermatitis and psoriasis

Despite recent advances in understanding microbial diversity in skin homeostasis, the relevance of microbial dysbiosis in inflammatory disease is poorly understood. Here we perform a comparative analysis of skin microbial communities coupled to global patterns of cutaneous gene expression in patients with atopic dermatitis or psoriasis. The skin microbiota is analysed by 16S amplicon or whole genome sequencing and the skin transcriptome by microarrays, followed by integration of the data layers. We find that atopic dermatitis and psoriasis can be classified by distinct microbes, which differ from healthy volunteers microbiome composition. Atopic dermatitis is dominated by a single microbe (Staphylococcus aureus), and associated with a disease relevant host transcriptomic signature enriched for skin barrier function, tryptophan metabolism and immune activation. In contrast, psoriasis is characterized by co-occurring communities of microbes with weak associations with disease related gene expression. Our work provides a basis for biomarker discovery and targeted therapies in skin dysbiosis.

Atopic dermatitis (AD) and psoriasis (PSO) are associated with dysbiosis. Here, by analyses of skin microbiome and host transcriptome of AD and PSO patients, the authors find distinct microbial and disease-related gene transcriptomic signatures that differentiate both diseases.

New treatments for atopic dermatitis targeting beyond IL-4/IL-13 cytokines

OBJECTIVE

Atopic dermatitis (AD) is an increasingly common inflammatory skin disease undergoing significant revolution in recent years. New data on disease pathogenesis advanced the developments of novel therapeutics, mainly for patients with moderate to severe conditions, for whom treatment options have been largely insufficient for many years.

DATA SOURCES

Review of recent studies investigating systemic treatments for AD.

STUDY SELECTIONS

Relevant literature concerning novel therapeutics for AD beyond targeted monoclonal antibodies antagonizing selectively interleukin (IL)-4 or IL-13 was obtained from a PubMed and clinicaltrials.gov search and summarized.

RESULTS

Multiple clinical trials of both nonspecific as well as specific agents revealed favorable outcomes in AD, including JAK inhibitors, a dual JAK/SYK inhibitor, a histamine H4R antagonist, antagonists of the TSLP/OX40L axis, an IL-22 inhibitor, and IL-33 and IL-17C antagonists. Importantly, negative trials were published as well (eg, phosphodiesterase 4 inhibitor, apremilast).

CONCLUSION

In this rapidly evolving field of AD treatments, a completely new treatment paradigm will be available in the near future.

Topical agents for the treatment of atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is perhaps the most common inflammatory skin disorder worldwide, with an increasing incidence in developed countries. The mainstay treatment for patients with AD is topical therapies, which are used not only by the mild patients but also by the moderate-to-severe patients, in conjunction with systemic treatment. While topical steroids and calcineurin antagonists are widely used, these are associated with long-term cutaneous adverse effects (AEs) or a black box warning, preventing their chronic use. Areas covered: The aim of this review is to provide a comprehensive overview of new and upcoming topical therapies currently in development and undergoing clinical trials, as well as their safety and efficacy profiles, and discuss current topicals used in the management of AD. Expert opinion: AD is a heterogeneous disease with complex pathophysiology. Treatments available to date for AD provide disease control; however, patients struggle to find an optimized therapeutic regimen they may use long term and without severe effects. Novel therapies are currently under investigation, with the hope of shifting the paradigm of AD management from symptom control to disease eradication.

Optimization of placebo use in clinical trials with systemic treatments for atopic dermatitis: an International Eczema Council survey-based position statement

BACKGROUND

As novel systemic therapeutics for patients with atopic dermatitis (AD) are developed, ethical and methodological concerns regarding placebo-controlled-trials (PCT) have surfaced.

OBJECTIVE

To guide the design and implementation of PCT in AD, focusing on trials with systemic medications.

METHODS

A subgroup of the International Eczema Council (IEC) developed a consensus e-survey, which was disseminated to IEC members.

RESULTS

The response rate was 43/82 (52%). Consensus was reached on 24/27 statements and on 3/11 options from multiple-selection statements, including: performing monotherapy studies in proof-of-concept phases; avoiding concomitant topical corticosteroids or calcineurin inhibitors until a predefined timepoint as rescue (borderline consensus); selection of sites and assessors with recognized expertise in AD clinical trials; clear definition and identification of baseline disease severity; minimizing time and proportion of patients on placebo; using daily emollients with several options provided; instigating open-label extension studies for enrolment after a predefined timepoint; and including outcomes which set a higher bar for disease clearance.

CONCLUSION

Conducting PCT in AD requires balancing several, sometimes opposing principles, including ethics, methodology, regulatory requirements and real-world needs. This paper can provide a framework for conducting PCT with systemic medications for patients with AD.

Atopic dermatitis yardstick: Practical recommendations for an evolving therapeutic landscape

The implementation of treatment guidelines for atopic dermatitis is challenging, in part because of different guidance documents being used by different groups of specialists and in part because the language of guidelines often reflects the evidence base rather than the practical "how to." The Atopic Dermatitis Yardstick is part of a series developed in response to the need to proactively address the loss of disease control for atopic illnesses at all levels of severity. It presents a comprehensive update on how to conduct a sustained step-up in therapy for the patient with inadequately controlled or poorly controlled atopic dermatitis. Patient profiles, based on current guidelines and the authors' combined clinical experience, provide a practical and clinically meaningful guide to aid physicians in helping their patients achieve the goal of clear to almost clear. The intent is not to replace guidelines but to complement their recommendations incorporating the latest research and therapies.

Baseline IL-22 expression in patients with atopic dermatitis stratifies tissue responses to fezakinumab

BACKGROUND

IL-22 is potentially a pathogenic cytokine in patients with atopic dermatitis (AD), but the molecular effects of IL-22 antagonism have not been defined in human subjects.

OBJECTIVE

We sought to evaluate the cellular and molecular effects of IL-22 blockade in tissues from patients with moderate-to-severe AD.

METHODS

We assessed lesional and nonlesional skin from 59 patients with moderate-to-severe AD treated with anti-IL-22 (fezakinumab) versus placebo (2:1) using transcriptomic and immunohistochemistry analyses.

RESULTS

Greater reversal of the AD genomic profile was seen with fezakinumab versus placebo, namely 25.3% versus 10.5% at 4 weeks (P = 1.7 × 10-5) and 65.5% versus 13.9% at 12 weeks (P = 9.5 × 10-19), respectively. Because IL-22 blockade showed clinical efficacy only in patients with severe AD, we used baseline median IL-22 mRNA expression to stratify for high (n = 30) and low (n = 29) IL-22 expression groups. Much stronger mean transcriptomic improvements were seen with fezakinumab in the IL-22-high drug-treated group (82.8% and 139.4% at 4 and 12 weeks, respectively) than in the respective IL-22-high placebo-treated group (39.6% and 56.3% at 4 and 12 weeks) or the IL-22-low groups. Significant downregulations of multiple immune pathways, including TH1/CXCL9, TH2/CCL18/CCL22, TH17/CCL20/DEFB4A, and TH22/IL22/S100A's, were restricted to the IL-22-high drug group (P < .05). Consistently, tissue predictors of clinical response were mostly genes involved in T-cell and dendritic cell activation and differentiation.

CONCLUSIONS

This is the first report showing a profound effect of IL-22 blockade on multiple inflammatory pathways in AD. These data, supported by robust effects in patients with high IL-22 baseline expression, suggest a central role for IL-22 in AD, indicating the need for a precision medicine approach for improving therapeutic outcomes in patients with AD.

Cat Allergy as a Source Intensification of Atopic Dermatitis in Adult Patients

Atopic dermatitis (AD) is characterized by exacerbations and remissions of eczematous skin, underlain by impaired skin barrier and aberrant Th2-type and Th-22 cytokine production. A number of allergens, in particular contact with fur animals, may aggravate the disease. This study seeks to define the influence of having a regular contact with a pet cat at home on the severity of symptoms and signs of AD. We addressed the issue using the SCORing Atopic Dermatitis (SCORAD) and visual analog (VAS) scores to assess the intensity of pruritus and by measuring the blood content of specific IgE and IL-4, IL-13, and IL-22 cytokines. The study group consisted of 47 adult patients suffering from AD since childhood, 18 of whom declared having regular contact with a cat and the remaining 29 who denied it. There also was a control group consisted of 16 healthy volunteers with no AD signs. The SCORAD and VAS scores were significantly higher in patients in contact with a cat than in those without it (median SCORAD 61.0 vs. 50.4 and VAS 9.0 vs. 4.0 points, respectively). The sIgE of a majority of patients (94.4%) in contact with a cat was in Class V-VI, compared with just a few patients (3.4%) with no such contact, having sIgE in the same classes (p < 0.001). Significant correlations were revealed between SCORAD and VAS scores and the class level of serum sIgE value. In addition, IL-22 was a single elevated cytokine, only in the patients in contact with a cat, and it correlated with pruritus severity. The results of the study underline the need to beware of the cat fur allergen, and they stress forethought and caution in acquiring and keeping a pet cat by patients suffering from AD.

Dupilumab progressively improves systemic and cutaneous abnormalities in patients with atopic dermatitis

BACKGROUND

Dupilumab is an IL-4 receptor α mAb inhibiting signaling of IL-4 and IL-13, key drivers of type 2-driven inflammation, as demonstrated by its efficacy in patients with atopic/allergic diseases.

OBJECTIVE

This placebo-controlled, double-blind trial (NCT01979016) evaluated the efficacy, safety, and effects of dupilumab on molecular/cellular lesional and nonlesional skin phenotypes and systemic type 2 biomarkers of patients with moderate-to-severe atopic dermatitis (AD).

METHODS

Skin biopsy specimens and blood were evaluated from 54 patients randomized 1:1 to weekly subcutaneous doses of 200 mg of dupilumab or placebo for 16 weeks.

RESULTS

Dupilumab (vs placebo) significantly improved clinical signs and symptoms of AD, was well tolerated, and progressively shifted the lesional transcriptome toward a nonlesional phenotype (weeks 4-16). Mean improvements in a meta-analysis-derived AD transcriptome (genes differentially expressed between lesional and nonlesional skin) were 68.8% and 110.8% with dupilumab and -10.5% and 55.0% with placebo (weeks 4 and 16, respectively; P < .001). Dupilumab significantly reduced expression of genes involved in type 2 inflammation (IL13, IL31, CCL17, CCL18, and CCL26), epidermal hyperplasia (keratin 16 [K16] and MKi67), T cells, dendritic cells (ICOS, CD11c, and CTLA4), and T_H17/T_H22 activity (IL17A, IL-22, and S100As) and concurrently increased expression of epidermal differentiation, barrier, and lipid metabolism genes (filaggrin [FLG], loricrin [LOR], claudins, and ELOVL3). Dupilumab reduced lesional epidermal thickness versus placebo (week 4, P = .001; week 16, P = .0002). Improvements in clinical and histologic measures correlated significantly with modulation of gene expression. Dupilumab also significantly suppressed type 2 serum biomarkers, including CCL17, CCL18, periostin, and total and allergen-specific IgEs.

CONCLUSION

Dupilumab-mediated inhibition of IL-4/IL-13 signaling through IL-4 receptor α blockade significantly and progressively improved disease activity, suppressed cellular/molecular cutaneous markers of inflammation and systemic measures of type 2 inflammation, and reversed AD-associated epidermal abnormalities.

Atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, with a lifetime prevalence of up to 20% and substantial effects on quality of life. AD is characterized by intense itch, recurrent eczematous lesions and a fluctuating course. AD has a strong heritability component and is closely related to and commonly co-occurs with other atopic diseases (such as asthma and allergic rhinitis). Several pathophysiological mechanisms contribute to AD aetiology and clinical manifestations. Impairment of epidermal barrier function, for example, owing to deficiency in the structural protein filaggrin, can promote inflammation and T cell infiltration. The immune response in AD is skewed towards T helper 2 cell-mediated pathways and can in turn favour epidermal barrier disruption. Other contributing factors to AD onset include dysbiosis of the skin microbiota (in particular overgrowth of Staphylococcus aureus), systemic immune responses (including immunoglobulin E (IgE)-mediated sensitization) and neuroinflammation, which is involved in itch. Current treatments for AD include topical moisturizers and anti-inflammatory agents (such as corticosteroids, calcineurin inhibitors and cAMP-specific 3',5'-cyclic phosphodiesterase 4 (PDE4) inhibitors), phototherapy and systemic immunosuppressants. Translational research has fostered the development of targeted small molecules and biologic therapies, especially for moderate-to-severe disease.

Treatment of atopic dermatitis with tralokinumab, an anti-IL-13 mAb

BACKGROUND

IL-13 has an important role in atopic dermatitis (AD) pathogenesis. Tralokinumab is a fully human mAb that potently and specifically neutralizes IL-13.

OBJECTIVE

We sought to evaluate the efficacy and safety of tralokinumab in adults with moderate-to-severe AD.

METHODS

In this phase 2b study (NCT02347176), 204 adults were randomized 1:1:1:1 to receive 45, 150, or 300 mg of subcutaneous tralokinumab, or placebo, every 2 weeks for 12 weeks with concomitant topical glucocorticoids. Coprimary end points were change from baseline in Eczema Area Severity Index score and percentage of participants with an Investigator's Global Assessment response (0/1 score and reduction of ≥2 grades from baseline) at week 12.

RESULTS

At week 12, 300 mg of tralokinumab significantly improved change from baseline in Eczema Area Severity Index score versus placebo (adjusted mean difference, -4.94; 95% CI, -8.76 to -1.13; P = .01), and a greater percentage of participants achieved an Investigator's Global Assessment response (26.7% vs 11.8%). Greater responses were found in participants with greater concentrations of biomarkers of increased IL-13 activity. Participants treated with 300 mg of tralokinumab demonstrated improvements in SCORAD, Dermatology Life Quality Index, and pruritus numeric rating scale (7-day mean) scores versus placebo. Upper respiratory tract infection was the most frequent treatment-emergent adverse event reported as related to study drug in the placebo (3.9%) and pooled tralokinumab (3.9%) groups.

CONCLUSIONS

Tralokinumab treatment was associated with early and sustained improvements in AD symptoms and an acceptable safety and tolerability profile, thereby providing evidence for targeting IL-13 in patients with AD.

Early-onset pediatric atopic dermatitis is characterized by TH2/TH17/TH22-centered inflammation and lipid alterations

BACKGROUND

Although atopic dermatitis (AD) often starts in early childhood, detailed tissue profiling of early-onset AD in children is lacking, hindering therapeutic development for this patient population with a particularly high unmet need for better treatments.

OBJECTIVE

We sought to globally profile the skin of infants with AD compared with that of adults with AD and healthy control subjects.

METHODS

We performed microarray, RT-PCR, and fluorescence microscopy studies in infants and young children (<5 years old) with early-onset AD (<6 months disease duration) compared with age-matched control subjects and adults with longstanding AD.

RESULTS

Transcriptomic analyses revealed profound differences between pediatric patients with early-onset versus adult patients with longstanding AD in not only lesional but also nonlesional tissues. Although both patient populations harbored TH2-centered inflammation, pediatric AD also showed significant TH17/TH22 skewing but lacked the TH1 upregulation that characterizes adult AD. Pediatric AD exhibited relatively normal expression of epidermal differentiation and cornification products, which is downregulated in adults with AD. Defects in the lipid barrier (eg, ELOVL fatty acid elongase 3 [ELOVL3] and diacylglycerol o-acyltransferase 2 [DGAT2]) and tight junction regulation (eg, claudins 8 and 23) were evident in both groups. However, some lipid-associated mediators (eg, fatty acyl-CoA reductase 2 and fatty acid 2-hydroxylase) showed preferential downregulation in pediatric AD, and lipid barrier genes (FA2H and DGAT2) showed inverse correlations with transepidermal water loss, a functional measure of the epidermal barrier.

CONCLUSIONS

Skin samples from children and adult patients with AD share lipid metabolism and tight junction alterations, but epidermal differentiation complex defects are only present in adult AD, potentially resulting from chronic immune aberration that is not yet present in early-onset disease.

Treatment with silver nitrate versus topical steroid treatment for umbilical granuloma: A non-inferiority randomized control trial

Objective

The aim of this prospective multicenter randomized controlled trial was to compare the efficacy of silver nitrate cauterization against that of topical steroid ointment in the treatment of neonatal umbilical granuloma.

Methods

An open-label, non-inferiority randomized controlled trial was conducted from January 2013 to January 2016. The primary endpoint for the silver nitrate cauterization and topical steroid ointment groups was the healing rate after 2 weeks of treatment, applying a non-inferiority margin of 10%. The healing rate was evaluated until completion of 3 weeks of treatment.

Results

Participants comprised 207 neonates with newly diagnosed umbilical granuloma, randomized to receive silver nitrate cauterization (n = 104) or topical steroid ointment (n = 103). Healing rates after 2 weeks of treatment were 87.5% (91/104) in the silver nitrate cauterization and 82% (82/100) in the topical steroid ointment group group. The difference between groups was -5.5% (95% confidence interval, -19.1%, 8.4%), indicating that the non-inferiority criterion was not met. After 3 weeks of treatment, the healing rate with topical steroid ointment treatment was almost identical to that of silver nitrate cauterization (94/104 [90.4%] vs. 91/100 [91.0%]; 0.6% [-13.2 to 14.3]). No major complications occurred in either group.

Conclusions

This study did not establish non-inferiority of topical steroid ointment treatment relative to silver nitrate cauterization, presumably due to lower healing rates than expected leading to an underpowered trial. However, considering that silver nitrate cauterization carries a distinct risk of chemical burns and that the overall efficacy of topical steroid ointment treatment is similar to that of silver nitrate cauterization, topical steroid ointment might be considered as a good alternative in the treatment of neonatal umbilical granuloma due to its safety and simplicity. To clarify non-inferiority, a larger study is needed.

Efficacy and safety of lebrikizumab (an anti-IL-13 monoclonal antibody) in adults with moderate-to-severe atopic dermatitis inadequately controlled by topical corticosteroids: A randomized, placebo-controlled phase II trial (TREBLE)

BACKGROUND

Interleukin (IL)-13 plays a key role in type 2 inflammation and is an emerging pathogenic mediator in atopic dermatitis (AD).

OBJECTIVE

We investigated the efficacy and safety of lebrikizumab, an IL-13 monoclonal antibody, as an add-on to topical corticosteroid (TCS) treatment.

METHODS

A randomized, placebo-controlled, double-blind, phase 2 study. Adults with moderate-to-severe AD were required to use TCS twice daily and then randomized (1:1:1:1) to lebrikizumab 125 mg single dose, lebrikizumab 250 mg single dose, lebrikizumab 125 mg every 4 weeks for 12 weeks, or placebo every 4 weeks for 12 weeks, after a 2-week TCS run-in. The primary endpoint was percentage of patients achieving Eczema Area and Severity Index (EASI)-50 at week 12.

RESULTS

In total, 209 patients received the study drug. At week 12, significantly more patients achieved EASI-50 with lebrikizumab 125 mg every 4 weeks (82.4%; P = .026) than placebo every 4 weeks (62.3%); patients receiving a single dose of lebrikizumab showed no statistically significant improvements in EASI-50 compared with placebo. Adverse events were similar between groups (66.7% all lebrikizumab vs 66.0% placebo) and mostly mild or moderate.

LIMITATIONS

Protocol-mandated twice daily TCS treatment limits our understanding of the efficacy of lebrikizumab as a monotherapy. The short study duration did not enable long-term efficacy or safety evaluations.

CONCLUSION

When combined with TCS, lebrikizumab 125 mg taken every 4 weeks led to a significant improvement and was well tolerated in patients with moderate-to-severe AD.

Immunologic, microbial, and epithelial interactions in atopic dermatitis

OBJECTIVE

To provide an overview of studies contributing to the understanding of immunologic, microbial, and epithelial interactions in atopic dermatitis.

DATA SOURCES

PubMed literature review (2000-2017) and meeting abstracts from recent international dermatology conferences.

STUDY SELECTIONS

Articles discussing primarily human disease.

RESULTS

Clinical studies showed that atopic dermatitis is a type 2 immune-centered disease with a systemic inflammatory component but with heterogeneous treatment responses. This suggests that other factors are likely involved in shaping the skin disease phenotype, including microbial dysbiosis and epidermal barrier dysfunction.

CONCLUSION

Recent clinical investigation has significantly expanded our knowledge on disease pathogenesis in atopic dermatitis, and current and future clinical trials will most likely further help to elucidate this complex, heterogeneous skin disease.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The immunology of atopic dermatitis and its reversibility with broad-spectrum and targeted therapies

Atopic dermatitis (AD), the most common chronic inflammatory skin disease, is driven by both terminal keratinocyte differentiation defects and strong type 2 immune responses. In contrast to chronic plaque-type psoriasis, AD is now understood to be a much more heterogeneous disease, with additional activation of T_H22, T_H17/IL-23, and T_H1 cytokine pathways depending on the subtype of the disease. In this review we discuss our current understanding of the AD immune map in both patients with early-onset and those with chronic disease. Clinical studies with broad and targeted therapeutics have helped to elucidate the contribution of various immune axes to the disease phenotype. Importantly, immune activation extends well beyond lesional AD because nonlesional skin and the blood component harbor AD-specific inflammatory changes. For this reason, future therapeutics will need to focus on a systemic treatment approach, especially in patients with moderate-to-severe disease.