Atopic dermatitis

Dietary glutamine supplementation improves both Th1 and Th17 responses via CARD11-mTORC1 pathway in murine model of atopic dermatitis

Glutamine (GLN) is considered an immunomodulatory nutrient, while caspase recruitment domain 11 (CARD11) is a susceptibility locus for atopic dermatitis (AD). T-cell antigen receptor (TCR)-stimulated GLN uptake requires CARD11. However, the specific pathogenesis of AD via GLN uptake remains unclear. This study aimed to elucidate the association between dietary GLN supplementation and the CARD11 pathway in the pathogenesis of AD, focusing on T helper type 1 (Th1) and Th17 cell expression in AD. Herein, wild-type (WT) mice with house dust mite epidermal-sensitized skin exhibited increased expression of interferon-gamma (IFN-gamma) and interleukin (IL)-17, whereas CARD11 deficiency impaired Th1 and Th17 responses at the same site. CARD11 is a key mediator of Th1 and Th17 expression in AD. Additionally, we suppressed mammalian target of rapamycin complex 1 (mTORC1) signaling, downstream of CARD11, to underscore the critical role of CARD11 in mediating Th1 and Th17 expression in AD. Further, dietary supplementation of GLN to CARD11-/- mice restored Th1 and Th17 responses, whereas inflammatory expression was reduced in WT mice, and p-CARD11 expression and mTORC1 signaling activity were increased in JPM50.6 cells and CARD11-/- mice. Upon inhibiting the GLN transporter, alanine-serine-cysteine transporter carrier 2 (ASCT2), we observed that the Th1 and Th17 response in AD was reduced. Conclusively, ASCT2-mediated GLN uptake improves the expression of Th1 and Th17 cells via CARD11-mTORC1 signaling pathway in AD, suggesting the potential of glutamine supplementation for AD treatment.

A microarray-based IgE-molecular mimicry index (IgE-MMI): A biomarker for disease severity, clinical phenotypes, and therapeutic response in atopic dermatitis?

BACKGROUND

The role of autoimmune IgE responses in atopic dermatitis (AD) is highly debated. While IgE targeting self-proteins has been extensively studied, IgE responses induced by human-homologous exogenous molecular allergens (HEMAs) remains less understood.

AIM

To investigate whether IgE antibody responses to HEMAs are associated with AD, its severity, and response to dupilumab.

METHODS

We enrolled 3325 participants with a history of allergic diseases, including 577 (17.3%) diagnosed with AD. Serum IgE antibodies against 183 exogenous allergenic molecules were measured using the IgE microarray (Allergy Explorer-ALEX-2®, MADX, Vienna). Based on international classification criteria, participants were stratified by AD severity and clinical phenotypes. For each patient, we developed an 'IgE molecular-mimicry index' (IgE-MMI), calculated from IgE reactivity to a panel of five HEMA protein families: arginine kinase, enolase (ENO), cyclophilin (CYP), lipocalin, and MnSOD. Logistic regression was employed to assess the association between IgE to HEMAs or IgE-MMI and AD, its severity, and response to dupilumab.

RESULTS

IgE sensitization to most HEMAs (32/48, 67%), but only to a small fraction of non-HEMAs (3/135, 2.2%), was significantly more common in patients with severe AD compared to other patient groups. The IgE-MMI was positive in 295/2748 (10.7%) of allergic patients without AD, and in 58/283 (20%), 52/134 (39%), and 86/160 (54%) of patients with remitting, moderate, or severe AD, respectively. It was strongly associated with specific phenotypes, such as flexural dermatitis (OR 8.4, 95% CI: 6.3-11.2), head and neck dermatitis (OR: 16.5, 95% CI: 7.4-37.2), and generalized eczema (OR: 8.6, 95% CI: 4.9-15.6). Poor response to dupilumab was associated with IgE antibodies to ENO (OR: 22.7, 95% CI: 1.7-302.9), but inversely associated with IgE antibodies to MnSOD (OR: 0.1, 95% CI: 0.02-0.8) and NPC-2 from dust mites (OR: 0.1, 95% CI: 0.01-0.9).

CONCLUSION

IgE microarrays are useful for broadly assessing IgE to HEMAs in allergic patients. IgE reactivity to HEMAs and a positive IgE-MMI may serve as valuable biomarkers for severe AD, its clinical phenotypes, and the response to dupilumab.

Effect of benralizumab on inflammation in skin after intradermal allergen challenge in patients with moderate-to-severe atopic dermatitis

Background

Atopic dermatitis (AD) is a skin barrier dysfunction characterized by tissue eosinophilia.

Objective

In patients with AD, we evaluated the effect of eosinophil depletion with benralizumab on markers of inflammation in skin after intradermal allergen challenge.

Methods

A total of 20 patients with moderate-to-severe AD completed a randomized, double-blind, placebo-controlled parallel-group study comparing 3 doses of benralizumab (30 mg each) administered subcutaneously every 4 weeks (n = 9) with placebo (n = 11). Allergen and saline control intradermal challenges were conducted before and after treatment, with skin biopsy samples collected 24 hours after challenge. Early and late cutaneous responses were measured by skin wheal size. Levels of eosinophils and IL-5 receptor-α-bearing cells, including eosinophil progenitor (EoP) cells, basophils, and mast cells, in papillary dermis were measured by immunofluorescence microscopy, and levels of EoP cells, hematopoietic progenitor cells, and type 2 innate lymphoid cells in the blood were measured by flow cytometry. Outcomes were compared between the placebo and benralizumab treatment groups by using the Mann-Whitney U test.

Results

Benralizumab reduced eosinophil counts in the blood (P < .0001) and allergen-challenged skin, as measured by hematoxylin and eosin staining and eosinophil cationic protein antibody concentration (P < .05). Benralizumab lowered the levels of EoP cells, mast cells, and basophils in the skin, as well as the levels of EoP cells, hematopoietic progenitor cells, and type 2 innate lymphoid cells in the blood (all P < .05). There was a trend toward improvement in the early cutaneous response (P = .095) but no effect on the late cutaneous response.

Conclusion

In patients with moderate-to-severe AD, benralizumab treatment significantly inhibited accumulation of eosinophils and other IL-5 receptor-α-expressing cells in the papillary dermis after intradermal allergen challenge. Targeting IL-5 receptor-α-positive cells did not modulate the size of the allergen-induced skin wheal (ClincialTrials.gov identifier NCT03563066).

Cost-Effectiveness Study of Difamilast 1% for the Treatment of Atopic Dermatitis in Adult Japanese Patients

INTRODUCTION

Difamilast has proven to be an effective treatment for the treatment of atopic dermatitis (AD) in Japan, but its cost-effectiveness remains unknown. Therefore, the objective of the current study was to determine the cost-effectiveness of difamilast 1% compared with delgocitinib 0.5% in Japanese adult patients with moderate-to-severe AD and compared with placebo in Japanese adult patients with all-severity AD from a Japanese public health-care perspective.

METHODS

The analysis was conducted using a cost-effectiveness model from the Japanese public health-care perspective. This model had four health states ("clear," "mild," "moderate," and "severe") defined according to the Eczema Area and Severity Index score. The time horizon of the analysis was 1 year. Because the analysis period was short, no discount rate was applied. The proportions of patients previously estimated by the anchored matching-adjusted indirect comparison were implemented in the model. The model was further populated with data from the literature. The main model outcomes were quality-adjusted life-years (QALY), costs, and outcomes, including the incremental cost-effectiveness ratio. All prices were stated in JPY at the price level from 2018 April to 2019 March. One-way sensitivity analysis and probabilistic sensitivity analysis (PSA) were performed to assess the robustness of the results.

RESULTS

In the base case, the cost-effectiveness of difamilast 1% compared with delgocitinib 0.5% and placebo was JPY 827,054/QALY and JPY 1,518,657/QALY, respectively. The PSA showed that the cost-effectiveness of difamilast 1% compared with delgocitinib 0.5% and placebo had a 66.6% and 99.6% probability of being below the JPY 5 million/QALY threshold, respectively.

CONCLUSION

The results suggest that difamilast 1% is a more cost-effective treatment option compared with delgocitinib 0.5% in Japanese adult patients with moderate-to-severe AD and compared with placebo in adult patients with all-severity AD from a Japanese public health-care perspective.

Investigation on the in vitro effects of resveratrol on peripheral blood mononuclear cells harvested from healthy and atopic dogs

Canine atopic dermatitis (AD) is a common skin disease. Many therapeutic options are available to decrease inflammation and ameliorate pruritus. However, those treatments are associated with side effects, a long lag phase for efficacy, or high expense. Natural plant extracts have been identified as possible, safer alternatives to traditional anti-inflammatory and antipruritic drugs. Resveratrol has been revisited as a new, possible alternative for its numerous beneficial properties. The purpose of this study was to evaluate the in vitro effects of resveratrol on peripheral blood mononuclear cells (PBMC) harvested from healthy and atopic privately-owned dogs. The PBMC harvested from nine healthy and 11 atopic dogs were isolated and exposed to four concentrations (1.5-9 μg/mL) of resveratrol both with or without phytohemagglutinin stimulation. After 24 h cytotoxicity, host defense peptides (HDPs), as well as oxidative stress (catalase and superoxide dismutase), and pro-inflammatory cytokines were assessed. Cytotoxicity was not observed in either group under any experimental conditions. An increase in catalase was only seen in healthy PBMC after exposure to low concentrations of resveratrol (p ≤ 0.03). Resveratrol did not show any effect on canine HDPs. Compared to baseline, there was a significant reduction in monocyte chemotactic protein-1 and interleukin-6 after exposure to 9 μg/mL of resveratrol in unstimulated healthy (p = 0.029) and stimulated atopic (p = 0.0075) PBMC. In conclusion, these data confirm the overall lack of cytotoxicity of resveratrol on healthy and atopic PBMC at the tested concentrations. However, at the concentrations tested, there was only a minimal effect of resveratrol on the secretion of HDPs and pro-inflammatory cytokines.

Particulate Matter-Induced Emerging Health Effects Associated with Oxidative Stress and Inflammation

Environmental pollution continues to increase with industrial development and has become a threat to human health. Atmospheric particulate matter (PM) was designated as a Group 1 carcinogen by the International Agency for Research on Cancer in 2013 and is an emerging global environmental risk factor that is a major cause of death related to cardiovascular and respiratory diseases. PM is a complex composed of highly reactive organic matter, chemicals, and metal components, which mainly cause excessive production of reactive oxygen species (ROS) that can lead to DNA and cell damage, endoplasmic reticulum stress, inflammatory responses, atherosclerosis, and airway remodeling, contributing to an increased susceptibility to and the exacerbation of various diseases and infections. PM has various effects on human health depending on the particle size, physical and chemical characteristics, source, and exposure period. PM smaller than 5 μm can penetrate and accumulate in the alveoli and circulatory system, causing harmful effects on the respiratory system, cardiovascular system, skin, and brain. In this review, we describe the relationship and mechanism of ROS-mediated cell damage, oxidative stress, and inflammatory responses caused by PM and the health effects on major organs, as well as comprehensively discuss the harmfulness of PM.

The paradigm shift in drug development for atopic dermatitis: Addressing the variables of the equation leading to disease modification

The recent development of new therapies for atopic dermatitis (AD) has greatly benefited from the advances in understanding the mechanisms underlying this disease. This progress now allows one to envisage pushing the therapeutic boundaries beyond the simple symptomatic treatment of the exacerbations of AD and considering new therapeutic strategies aimed to allow an off-therapy long-term and deep remission, that is, disease modification. Owing to the complexity of the phenotype and underlying mechanisms of AD, it is expected that this will not fit to the current one-size-fits-all model in drug development. Thus, aiming at disease modification will lead to a paradigm shift in drug development strategy in AD requiring the consideration of a precision medicine approach with a phenotype-endotype (biomarker)-based stratification as well as a consensus definition of specific study endpoints for the clinical development program. This review addresses the scientific rationale for this strategy, some general aspects of the design of confirmatory clinical trials, and the variables along the Population, Intervention, Comparator, and Outcome framework to be addressed for reaching the ultimate goal of disease modification in AD.

The therapeutic effect of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol on chemically induced atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease worldwide. However, it is still urgent to develop innovative treatments that can effectively manage refractory patients with unpredictable chronic disease courses. In this study, we evaluated the therapeutic efficacy of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) as a novel agent for AD treatment using a human-like mouse model of AD. PLAG significantly improved 2,4-dinitrochlorobenzene (DNCB)-induced AD skin lesions compared to those in mice treated with DNCB alone. PLAG substantially modulated the AD-induced infiltration of monocytes and eosinophils into skin lesions and humoral systemic responses involving immunoglobulin E (IgE), interleukin (IL)-4, and IL-13, restoring them to a normal state. Next, we compared the therapeutic efficacy of PLAG and abrocitinib for severe AD treatment. PLAG exhibited a significant therapeutic effect on AD skin lesions compared to abrocitinib. Unlike abrocitinib, PLAG significantly reduced AD-induced eosinophil infiltration to a level similar to that observed in untreated negative controls. Notably, both PLAG and abrocitinib downregulated IgE, IL-4, and IL-13 in a similar pattern, reaching levels similar to those in the untreated negative controls. Our findings strongly suggest that PLAG may serve as a therapeutic agent for AD with an efficacy comparable to that of abrocitinib.

Efficacy and safety of dupilumab with concomitant topical corticosteroids in Japanese pediatric patients with moderate-to-severe atopic dermatitis: A randomized, double-blind, placebo-controlled phase 3 study

BACKGROUND

We investigated the efficacy and safety of dupilumab in Japanese patients aged ≥6 months to <18 years old with moderate-to-severe atopic dermatitis not adequately controlled with existing therapies.

METHODS

In this randomized, double-blind, phase 3 study, patients received dupilumab (n = 30) or placebo (n = 32) with concomitant topical corticosteroids for 16 weeks, then all patients received dupilumab from 16 to 52 weeks. The primary endpoint was the proportion of patients with ≥75% improvement in Eczema Area and Severity Index (EASI) score from baseline (EASI-75) to Week 16. Key secondary endpoints included changes in EASI score, proportion of patients with investigator global assessment (IGA) scores of 0/1, and changes in worst daily itch numerical rating scale (NRS) scores (evaluated in patients aged ≥6 to <12 years [n = 35]).

RESULTS

At Week 16, more patients achieved EASI-75 with dupilumab than placebo (43.3% vs 18.8%; P = 0.0304), and the least squares mean (LSM) difference in percent change in EASI scores at Week 16 of dupilumab vs placebo was -39.4% (P = 0.0003). However, no significant difference in the proportion of patients achieving IGA scores of 0/1 at Week 16 with dupilumab versus placebo were seen (10.0% vs 9.4%; P = 0.8476). The percent change in worst daily itch NRS scores at Week 16 was higher with dupilumab (LSM difference: -33.3%; nominal P = 0.0117). Dupilumab was well tolerated; no new safety signals were identified.

CONCLUSIONS

Dupilumab showed consistent efficacy and was well tolerated in Japanese patients aged ≥6 months to <18 years with moderate-to-severe atopic dermatitis previously insufficiently controlled with existing therapies.

Pinewood VOC emissions protect from oxazolone-induced inflammation and dysbiosis in a mouse model of atopic dermatitis

Pinewood, increasingly used in construction and interior fittings, emits high amounts of volatile organic compounds (VOCs), which tend to accumulate in indoor air. Whether indoor VOCs affect the development of atopic dermatitis (AD) is a matter of debate. We aimed to evaluate the effects of pinewood VOCs on the development of AD-like inflammatory phenotype and linked microbiome alterations, both hallmarks of AD. An oxazolone-induced mouse model of AD was exposed to three different VOC concentrations emitted by pinewood plates throughout the experiment. The disease course and associated immunological and microbiological changes were evaluated. To validate and translate our results to humans, human keratinocytes were exposed to a synthetic pinewood VOCs mixture in an AD environment. Pinewood emitted mainly terpenes, which at a total concentration of 5 mg/m3 significantly improved oxazolone-induced key AD parameters, such as serum total IgE, transepidermal water loss, barrier gene alteration, inflammation, and dysbiosis. Notably, exposure to pinewood VOCs restored the loss of microbial richness and inhibit Staphylococci expansion characteristic of the oxazolone-induced mouse AD model. Most beneficial effects of pinewood VOCs were dose-dependent. In fact, lower (<3 mg/m3) or higher (>10 mg/m3) pinewood VOC levels maintained only limited beneficial effects, such as preserving the microbiome richness or impeding Staphylococci expansion, respectively. In the human in-vitro model, exposure of keratinocytes grown in an AD environment to a pinewood VOCs mixture reduced the release of inflammatory markers. In conclusion, our results indicate that airborne phytochemicals emitted from pinewood have beneficial effects on an AD-like phenotype and associated dysbiosis. These investigations highlight the effects of terpenes as environmental compounds in the prevention and/or control of atopic skin disease.

Berberine Inhibits the Inflammatory Response Induced by Staphylococcus aureus Isolated from Atopic Eczema Patients via the TNF-α/Inflammation/RAGE Pathways

Atopic eczema patients exhibit high levels of Staphylococcus aureus (S. aureus) skin colonization. S. aureus can stimulate macrophages and the expression of proinflammatory cytokines. Berberine (BBR), an alkaloid, attenuates S. aureus toxin production. This study investigated if BBR suppressed bacterial growth and inflammatory response induced by eczema-patient-derived S. aureus using murine macrophage (RAW 264.7) and human monocyte cell lines (U937). RAW 264.7 and U937 were treated with BBR at different concentrations and stimulated with heat-killed S. aureus (ATCC #33591) or S. aureus derived from severe eczema patients (EC01-EC10), who were undergoing topical steroid withdrawal, for 24 h. TNF-α protein levels were determined by ELISA, gene expression by qRT-PCR, cell cytotoxicity by trypan blue excursion, and reactive oxygen species (ROS) levels by fluorometric assay. BBR showed a bacteriostatic effect in S. aureus (ATCC strain #33591 and clinical isolates (EC01-EC10) and suppressed TNF-α production in RAW 264.7 and U937 cells exposed to heat-killed S. aureus (ATCC and clinical isolates) dose-dependently without any cell cytotoxicity. BBR (20 µg/mL) suppressed >90% of TNF-α production (p < 0.001), downregulated genes involved in inflammatory pathways, and inhibited S. aureus ROS production in U937 and RAW 264.7 cells (p < 0.01). BBR suppresses S. aureus-induced inflammation via inhibition of TNF-α release, ROS production, and expression of key genes involved in the inflammatory pathway.

Pioneering bioinformatics with agent-based modelling: an innovative protocol to accurately forecast skin or respiratory allergic reactions to chemical sensitizers

The assessment of the allergenic potential of chemicals, crucial for ensuring public health safety, faces challenges in accuracy and raises ethical concerns due to reliance on animal testing. This paper presents a novel bioinformatic protocol designed to address the critical challenge of predicting immune responses to chemical sensitizers without the use of animal testing. The core innovation lies in the integration of advanced bioinformatics tools, including the Universal Immune System Simulator (UISS), which models detailed immune system dynamics. By leveraging data from structural predictions and docking simulations, our approach provides a more accurate and ethical method for chemical safety evaluations, especially in distinguishing between skin and respiratory sensitizers. Our approach integrates a comprehensive eight-step process, beginning with the meticulous collection of chemical and protein data from databases like PubChem and the Protein Data Bank. Following data acquisition, structural predictions are performed using cutting-edge tools such as AlphaFold to model proteins whose structures have not been previously elucidated. This structural information is then utilized in subsequent docking simulations, leveraging both ligand-protein and protein-protein interactions to predict how chemical compounds may trigger immune responses. The core novelty of our method lies in the application of UISS-an advanced agent-based modelling system that simulates detailed immune system dynamics. By inputting the results from earlier stages, including docking scores and potential epitope identifications, UISS meticulously forecasts the type and severity of immune responses, distinguishing between Th1-mediated skin and Th2-mediated respiratory allergic reactions. This ability to predict distinct immune pathways is a crucial advance over current methods, which often cannot differentiate between the sensitization mechanisms. To validate the accuracy and robustness of our approach, we applied the protocol to well-known sensitizers: 2,4-dinitrochlorobenzene for skin allergies and trimellitic anhydride for respiratory allergies. The results clearly demonstrate the protocol's ability to differentiate between these distinct immune responses, underscoring its potential for replacing traditional animal-based testing methods. The results not only support the potential of our method to replace animal testing in chemical safety assessments but also highlight its role in enhancing the understanding of chemical-induced immune reactions. Through this innovative integration of computational biology and immunological modelling, our protocol offers a transformative approach to toxicological evaluations, increasing the reliability of safety assessments.

Immune-Molecular Link between Thyroid and Skin Autoimmune Diseases: A Narrative Review

Autoimmune skin disorders, including Psoriasis, Lichen Planus, Vitiligo, Atopic Dermatitis, and Alopecia Areata, arise from a combination of genetic predisposition, external factors, and immunological dysfunction. It is well-documented that there is a strong correlation between autoimmune thyroid diseases and a range of dermatological disorders, especially urticaria. This review investigates possible links between autoimmune thyroiditis and a broader spectrum of autoimmune skin conditions, analyzing shared genetic markers, immunological mechanisms, and clinical correlations. Common pathogenic mechanisms include disrupted immune tolerance and oxidative stress, leading to chronic inflammation. Genetic factors, such as IL-23 receptor gene variants, increase the risk for Psoriasis, Alopecia Areata, and Hashimoto's thyroiditis. Additionally, CTLA-4 mutations enhance susceptibility to autoimmune thyroid and skin disorders. Shared genetic susceptibility was also reported in Lichen Planus and Vitilgo, even if different genetic loci might be involved. The breakdown of the immune system can determine a pro-inflammatory state, facilitating the development of autoimmunity and auto-antibody cross-reactions. The presence of similar antigens in skin cells and thyrocytes might explain why both tissues are affected. The significant overlap between these conditions emphasizes the necessity for a comprehensive diagnosis workup and treatment. Future research should focus on clarifying specific immunological pathways and identifying novel biomarkers.

Clinical Characteristics and Therapeutic Management of Atopic Dermatitis in Elderly Patients Compared with Young Adult Patients: A Prospective Multicentre Study

Atopic dermatitis (AD) is the most common chronic inflammatory dermatitis in developed countries, and has a major impact on those affected. Little is known about AD in elderly patients. This prospective multicentre observational study described the clinical characteristics and burden of AD in elderly subjects ≥ 65 years, as well as the therapeutic options chosen for this population in routine care, and compared findings with those in young adults with AD < 30 years. Cohort data from adult patients with moderate-to-severe AD enrolled in a French national prospective registry (December 2020 to May 2023) were analysed. Patients ≥ 65 years made up 12.5% of the total adult cohort and presented less head-and-neck and extremity involvement, and were less affected by generalized forms than young adult patients. Elderly patients predominantly had late-onset AD and had similar disease severity to younger adults. Although the overall impact of AD appeared to be lower in elderly patients and treatment was initially less used in this age group, the substantial impact on sleep and psychiatric comorbidities was similar in older and younger adult patients. Better understanding of AD in elderly patients and the establishment of age-specific treatment guidelines may help dermatologists manage the disease in older people.

Tapinarof cream 1% once daily: Significant efficacy in the treatment of moderate to severe atopic dermatitis in adults and children down to 2 years of age in the pivotal phase 3 ADORING trials

BACKGROUND

Tapinarof cream 1% once daily (QD), a topical aryl hydrocarbon receptor agonist, downregulates pro-inflammatory Th2 cytokines, upregulates skin-barrier components, and reduces oxidative stress.

OBJECTIVE

To assess tapinarof efficacy and safety in adults and children down to 2 years of age with atopic dermatitis (AD).

METHODS

Eight hundred and thirteen patients were randomized to tapinarof or vehicle QD in two 8-week phase 3 trials.

RESULTS

The primary efficacy endpoint, Validated Investigator Global Assessment for Atopic Dermatitis score of 0 or 1 and ≥2-grade improvement from baseline at Week 8, was met with statistical significance in both trials: 45.4% versus 13.9% and 46.4% versus 18.0% (tapinarof vs vehicle; both P < .0001). Significantly superior Eczema Area and Severity Index 75 (EASI75) responses were also observed with tapinarof versus vehicle at Week 8: 55.8% versus 22.9% and 59.1% versus 21.2% (both P < .0001). Rapid improvements in patient-reported pruritus were also significant with tapinarof versus vehicle. Common adverse events (≥5%) of folliculitis, headache, and nasopharyngitis were mostly mild or moderate, with lower discontinuations due to adverse events in the tapinarof groups than with vehicle.

LIMITATIONS

Long-term efficacy was not assessed.

CONCLUSION

Tapinarof demonstrated highly significant efficacy and favorable safety and tolerability in a diverse population of patients with AD down to 2 years of age.

An Interim Report of a Phase 3, Long-Term, Open-Label Study to Evaluate Efficacy and Safety of Difamilast Ointment in Japanese Infants with Atopic Dermatitis

INTRODUCTION

Difamilast is the first selective phosphodiesterase 4 inhibitor approved for atopic dermatitis (AD) in Japan. A phase 3, 52-week, open-label study is ongoing to establish efficacy and safety of difamilast ointments in infants with AD aged 3 to < 24 months because a clinical study has not been conducted in this population.

METHODS

This study consisted of a 4-week primary evaluation period in which difamilast 0.3% ointment was applied twice daily to Japanese infants aged 3 to < 24 months (n = 41) and an ongoing 48-week long-term extension period in which difamilast 0.3% or 1% ointment was applied based on existing symptoms. The data on efficacy and safety of difamilast were obtained as of an interim report in the study period.

RESULTS

The response rate in Investigator's Global Assessment score was 45.0% at week 1, which was maintained at 56.1% at week 4 and 63.4% at the interim report. Infants achieved the response rate in Eczema Area and Severity Index 75 (improvement of ≥ 75%) of 47.5% at week 1, which further improved to 82.9% at week 4 and 78.1% at the interim report. Adverse events (AEs) were reported in 22 (53.7%) infants in the primary evaluation period: of those the most frequent AE was nasopharyngitis (19.5%) followed by dermatitis contact (7.3%). As of the interim report, 36 (87.8%) infants experienced AEs: of those, nasopharyngitis (70.7%) and gastroenteritis (22.0%) were most frequently observed. The total AEs were mostly mild or moderate in severity. No investigational medicinal product-related AEs and no AEs leading to discontinuation were reported.

CONCLUSION

Difamilast ointments applied twice daily to Japanese infants with AD aged 3 to < 24 months is effective and well tolerated as of the interim report in the study period. The final results will be reported in the near future.

CLINICAL TRIAL REGISTRATION

Clinical Trials. gov identifier: NCT05372653.

Transcriptional Profiling of Staphylococcus aureus during the Transition from Asymptomatic Nasal Colonization to Skin Colonization/Infection in Patients with Atopic Dermatitis

Staphylococcus aureus acts both as a colonizing commensal bacterium and invasive pathogen. Nasal colonization is associated with an increased risk of infection caused by the identical strain. In patients with atopic dermatitis (AD), the degree of S. aureus colonization is associated with the severity of the disease. Here, we comparatively analyzed the in vivo transcriptional profile of S. aureus colonizing the nose and non-diseased skin (non-lesional skin) as opposed to the diseased skin (lesional skin-defined here as infection) of 12 patients with AD. The transcriptional profile during the asymptomatic colonization of the nose closely resembled that of the lesional skin samples for many of the genes studied, with an elevated expression of the genes encoding adhesion-related proteins and proteases. In addition, the genes that modify and remodel the cell wall and encode proteins that facilitate immune evasion showed increased transcriptional activity. Notably, in a subgroup of patients, the global virulence regulator Agr (accessory gene regulator) and downstream target genes were inactive during nasal colonization but upregulated in the lesional and non-lesional skin samples. Taken together, our results demonstrate a colonization-like transcriptional profile on diseased skin and suggest a role for the peptide quorum sensing system Agr during the transition from asymptomatic nasal colonization to skin colonization/infection.

Restoration of Skin Barrier Abnormalities with IL4/13 Inhibitors and Jak Inhibitors in Atopic Dermatitis: A Systematic Review

Background and Objectives: Atopic dermatitis is a chronic inflammatory skin disorder with a significant burden on patients' quality of life. This systematic review aims to evaluate the restoration of skin barrier abnormalities with interleukin-4/interleukin-13 (IL-4/IL-13) inhibitors and Janus kinase (JAK) inhibitors in atopic dermatitis. Materials and Methods: A comprehensive review of the literature was conducted, focusing on studies that assess the use of IL-4/IL-13 inhibitors and JAK inhibitors for atopic dermatitis. We identified eligible studies by searching Medline via PubMed with a special focus on their effect on the restoration of the epidermal barrier. Included studies evaluated the transepidermal water loss (TEWL), the reduction in epidermal thickness (ET), the improvement in ceramide synthesis, and the increase in stratum corneum hydration (SCH) with IL-4/IL-13 inhibitors and JAK inhibitors. The quality of included studies was assessed using the ROBINS-I and the RoB 2.0 tool for assessing the risk of bias. Results: Ten of the included studies concern dupilumab, while two concern JAK inhibitors. Ten were observational studies and two were randomized controlled trials (RCTs). The total number of included participants was 378 concerning dupilumab and 38 concerning JAK inhibitors. Five studies did not include any comparison group, three included healthy volunteers, two were conducted versus placebo, and two compared dupilumab with other treatments. The follow-up period ranged between 29 days and 32 weeks. The results demonstrated a significant decrease in transepidermal water loss (TEWL) and an increase in SCH on eczematous lesions for patients with sustained response to dupilumab treatment and observed improvements in ET and filaggrin (FLG) staining, which further support the efficacy of JAK inhibitors in enhancing skin barrier function. Conclusions: This review underscores the efficacy of IL-4/IL-13 inhibitors in improving skin barrier function. However, the limited number of studies focusing on JAK inhibitors and the overall lack of RCTs highlight the need for further research to establish the definitive role of IL-4/IL-13 inhibitors and JAK inhibitors in the restoration of the skin barrier.

Langerhans cells: Central players in the pathophysiology of atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease worldwide. AD is a highly complex disease with different subtypes. Many elements of AD pathophysiology have been described, but if/how they interact with each other or which mechanisms are important in which patients is still unclear. Langerhans cells (LCs) are antigen-presenting cells (APCs) in the epidermis. Depending on the context, they can act either pro- or anti-inflammatory. Many different studies have investigated LCs in the context of AD and found them to be connected to all major mechanisms of AD pathophysiology. As APCs, LCs recruit other immune cells and shape the immune response, especially adaptive immunity via polarization of T cells. As sentinel cells, LCs are primary sensors of the skin microbiome and are important for the decision of immunity versus tolerance. LCs are also involved with the integrity of the skin barrier by influencing tight junctions. Finally, LCs are important cells in the neuro-immune crosstalk in the skin. In this review, we provide an overview about the many different roles of LCs in AD. Understanding LCs might bring us closer to a more complete understanding of this highly complex disease. Potentially, modulating LCs might offer new options for targeted therapies for AD patients.

Agrimonia coreana Extract Exerts Its Therapeutic Effect through CRAC Channel Inhibition for Atopic Dermatitis Treatment

Atopic dermatitis (AD) is a common allergic inflammatory skin condition marked by severe itching, skin lichenification, and chronic inflammation. AD results from a complex immune response, primarily driven by T lymphocytes and environmental triggers, leading to a disrupted epidermal barrier function. Traditional treatments, such as topical corticosteroids, have limitations due to long-term side effects, highlighting the need for safer alternatives. Here, we aimed to show that Agrimonia coreana extract (ACext) can be used in treating AD-related dermatologic symptoms. ACext could inhibit CRAC (Calcium Release-Activated Calcium) channel activity, reducing Orai1/CRAC currents and decreasing intracellular calcium signaling. This inhibition was further confirmed by the reduced IL-2 levels and T cell proliferation upon ACext treatment. In a mouse model of AD, ACext significantly ameliorates symptoms, improves histological parameters, and enhances skin barrier function, demonstrating its potential for treating AD.

Emu oil alleviates atopic dermatitis-like responses by inhibiting Cdc42 signaling of keratinocyte

Emu oil is the oil extracted from the body fat of the Australian bird emu. Although previous studies have reported that emu oil has anti-inflammatory effects, the effect and mechanism of emu oil on the treatment of atopic dermatitis have not been reported. Here, 2, 4-dinitrofluorobenzene was used to induce atopic dermatitis-like appearance on the back skin of C57BL/6 mice. And then, the effect of emu oil in the atopic dermatitis treatment was evaluated. We found that emu oil reduced the transdermal water loss in the atopic dermatitis model. Additionally, the epidermal thickness treated with emu oil was significantly thinner. The number of mast cells and inflammatory cells were significantly decreased. The thymic stromal lymphopoietin (TSLP), which is secreted by keratinocyte, was decreased significantly after treatment. Moreover, the serum levels of cytokines TSLP, interleukin-4, interleukin-13, and immunoglobulin (Ig) E were decreased after emu oil treatment. Surprisingly, we found that the high level of Cdc42 expression in the atopic dermatitis, which was decreased after emu oil treatment. To detect the role of Cdc42 in atopic dermatitis, we constructed atopic dermatitis model in mice with sustained activation of Cdc42 signaling. Furthermore, we have confirmed that emu oil demonstrates anti-inflammatory effects in atopic dermatitis by inhibiting the expression of Cdc42 signaling in keratinocytes. In conclusion, we discovered a new role of Cdc42 in the development of atopic dermatitis, which mediated the therapeutic effect of emu oil on atopic dermatitis.

Diminished γδ T Cells during Murine Allergic Skin Inflammation Is Mediated by IL-4 Signaling in Keratinocytes

Atopic dermatitis results in diminished barrier function and altered production of antimicrobial peptides. Dendritic epidermal T cells (DETCs) play an important role in the wound repair and inflammation process. Our previous work identified an IL-4-dependent loss of DETCs in Stat6VT mice and in the MC903-induced skin inflammation mouse model. However, the mechanisms through which IL-4 mediates the loss of DETCs are unclear. In this study, we show that IL-4Rα germline knockout mice (Il4ra-/-) have increased DETCs, faster wound healing, and increased epidermal differentiation complex gene and fibronectin expression. The absence of IL-4Rα minimized the MC903-induced loss of DETCs, and reciprocal bone marrow chimera experiments in Il4ra-/- and wild-type mice demonstrated structural nonhematopoietic IL-4-responsive cell-mediated DETC homeostasis. Skin keratinocyte-derived IL-15 decreased dramatically in the MC903 model, while injection of IL-15 rescued DETC loss by promoting DETC proliferation and limiting apoptosis. Conditional deletion of IL-4Rα from keratinocytes using Il4rafl/fl K14-Cre mice showed an increase of DETCs, increased IL-15 production, and diminished skin inflammation following wounding. These results suggest that IL-4-dependent effects on DETCs in allergic skin inflammation are mediated by the IL-4Rα receptor of keratinocytes.

IL-4 acts on skin-derived dendritic cells to promote the TH2 response to cutaneous sensitization and the development of allergic skin inflammation

BACKGROUND

Atopic dermatitis is characterized by scratching and a TH2-dominated local and systemic response to cutaneously encountered antigens. Dendritic cells (DCs) capture antigens in the skin and rapidly migrate to draining lymph nodes (dLNs) where they drive the differentiation of antigen-specific naive T cells.

OBJECTIVE

We sought to determine whether non-T-cell-derived IL-4 acts on skin-derived DCs to promote the TH2 response to cutaneously encountered antigen and allergic skin inflammation.

METHODS

DCs from dLNs of ovalbumin (OVA)-exposed skin were analyzed by flow cytometry and for their ability to polarize OVA-specific naive CD4+ T cells. Skin inflammation following epicutaneous sensitization of tape-stripped skin was assessed by flow cytometry of skin cells and real-time quantitative PCR of cytokines. Cytokine secretion and antibody levels were evaluated by ELISA.

RESULTS

Scratching upregulated IL4 expression in human skin. Similarly, tape stripping caused rapid basophil-dependent upregulation of cutaneous Il4 expression in mouse skin. In vitro treatment of DCs from skin dLNs with IL-4 promoted their capacity to drive TH2 differentiation. DCs from dLNs of OVA-sensitized skin of Il4-/- mice and CD11c-CreIl4rflox/- mice, which lack IL-4Rα expression in DCs (DCΔ/Δll4ra mice), were impaired in their capacity to drive TH2 polarization compared with DCs from controls. Importantly, OVA-sensitized DCΔ/Δll4ra mice demonstrated impaired allergic skin inflammation and OVA-specific systemic TH2 response evidenced by reduced TH2 cytokine secretion by OVA-stimulated splenocytes and lower levels of OVA-specific IgE and IgG1 antibodies, compared with controls.

CONCLUSIONS

Mechanical skin injury causes basophil-dependent upregulation of cutaneous IL-4. IL-4 acts on skin DCs that capture antigen and migrate to dLNs to promote their capacity for TH2 polarization and drive allergic skin inflammation.

Vitamin D and allergic diseases

In recent years, the relationship between vitamin D and allergic diseases has received widespread attention. As a fat-soluble vitamin, vitamin D plays a crucial role in regulating the immune system and may influence the onset and progression of diseases such as atopic dermatitis, allergic rhinitis, and asthma. To understand the underlying mechanisms, we have summarized the current research on the association between vitamin D and allergic diseases. We also discuss the impact of vitamin D on the immune system and its role in the course of allergic diseases, particularly focusing on how vitamin D supplementation affects the treatment outcomes of these conditions. We aim to provide a theoretical basis and practical guidance for optimizing the management and treatment of allergic diseases by modulating vitamin D levels.

Atopic Dermatitis

Atopic dermatitis (AD) is a common, chronic relapsing, and remitting inflammatory skin disease that is characterized by erythematous, scaly, and pruritic lesions often located over the flexural surfaces. Treatment goals of AD include the reduction of itching and burning, as well as the reduction of skin changes. Treatment of AD includes emollients and skin care, topical therapies including topical corticosteroids and steroid-sparing therapies, systemic therapies, and phototherapy.

Pediococcus pentosaceus KF159 alleviates house dust mite-induced atopic dermatitis by promoting IL10 production and regulatory T cell induction

Atopic dermatitis (AD) is a chronic immune disease that requires long-term management owing to its relative ease of recurrence. However, steroid treatment is limited owing to the side effects. Therefore, research on therapeutics with proven safety is required. Here, we evaluated the anti-allergic activity of the probiotic strain Pediococcus pentosaceus KF159 (PPKF159) with an ex vivo mouse model sensitized with ovalbumin (OVA) and a mouse model of AD induced by house dust mites. Changes in pathological symptoms were confirmed based on the clinical status of the AD-induced lesion site and the levels of T helper type 2 (Th2)-derived cytokines and immunoglobulin E (IgE). In addition, cell-mediated responses and related mechanisms were elucidated using various kinds of primary cells including splenocytes, mesenteric lymph nodes, Peyer's patch, and bone marrow-derived dendritic cells (BMDCs) in vitro and ex vivo. Oral administration of PPKF159 alleviated AD-like clinical symptoms such as erythema, edema, hemorrhage, and increased tissue thickness, and suppressed the production of Th2-associated cytokines and serum IgE while increasing T helper type 1 (Th1)-mediated cytokine production. PPKF159 induced tolerogenic dendritic cells (tol-DCs) by increasing the expression of ICOS-L, PD-L1, and IDO which were closely related to Treg induction in PPKF159-treated BMDCs. In addition, BMDCs and naive T cells co-cultured in the presence of PPKF159 had elevated IL10 production and increased proportions of CD4+CD25+Foxp3+ Tregs compared to the absence of PPKF159. This study showed that PPKF159 relieved AD-like clinical symptoms, modulated the Th1/Th2 immune balance, and inhibited IgE production in a mouse AD model. PPKF159 induced the transformation of dendritic cells into tolerogenic versions. These induced tol-DCs directly enhanced the production of IL10 or improved the secretion of IL10 through the induction of CD4+CD25+Foxp3+ Treg cells, thereby improving AD. These results suggest that PPKF159 can be applied as a functional food material for the treatment and prevention of AD.

Atopic Dermatitis Complicated by Recurrent Eczema Herpeticum Is Characterized by Multiple, Concurrent Epidermal Inflammatory Endotypes

A subgroup of patients with atopic dermatitis (AD) suffers from recurrent, disseminated herpes simplex virus skin infection, termed eczema herpeticum. To determine the transcriptional mechanisms of the skin and immune system pathobiology that underlie development of AD with eczema herpeticum (ADEH), we performed RNA-sequencing analysis of nonlesional skin (epidermis, dermis) from AD patients with and without a history of ADEH (ADEH+, n = 15; ADEH-, n = 13) along with healthy controls (n = 15). We also performed RNA sequencing on participants' plasmacytoid dendritic cells infected in vitro with herpes simplex virus 1. ADEH+ patients exhibited dysregulated gene expression, limited in the dermis (14 differentially expressed genes) and more widespread in the epidermis (129 differentially expressed genes). ADEH+-upregulated epidermal differentially expressed genes were enriched in type 2 cytokine (IL4R , CCL22, CRLF2, IL7R), interferon (CXCL10, ICAM1, IFI44, IRF7), and IL-36γ (IL36G) inflammatory gene pathways. All ADEH+ participants exhibited type 2 cytokine and inteferon endotypes, and 87% were IL36G-high. In contrast, these endotypes were more variably expressed among ADEH- participants. ADEH+ skin also had dysregulated epidermal differentiation complex gene expression of the late-cornified envelope, S100A, and small proline-rich gene families, which are involved in skin barrier function and antimicrobial activities. Plasmacytoid dendritic cell transcriptional responses to herpes simplex virus 1 infection were unaltered by ADEH status. The study concluded that the pathobiology underlying ADEH+ risk is associated with a unique, multifaceted epidermal inflammation that accompanies dysregulation of epidermal differentiation complex genes. These findings will help direct future studies that define how these inflammatory patterns may drive risk of eczema herpeticum in AD.

New Insights into the Role of PPARγ in Skin Physiopathology

Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor expressed in many tissues, including skin, where it is essential for maintaining skin barrier permeability, regulating cell proliferation/differentiation, and modulating antioxidant and inflammatory responses upon ligand binding. Therefore, PPARγ activation has important implications for skin homeostasis. Over the past 20 years, with increasing interest in the role of PPARs in skin physiopathology, considerable effort has been devoted to the development of PPARγ ligands as a therapeutic option for skin inflammatory disorders. In addition, PPARγ also regulates sebocyte differentiation and lipid production, making it a potential target for inflammatory sebaceous disorders such as acne. A large number of studies suggest that PPARγ also acts as a skin tumor suppressor in both melanoma and non-melanoma skin cancers, but its role in tumorigenesis remains controversial. In this review, we have summarized the current state of research into the role of PPARγ in skin health and disease and how this may provide a starting point for the development of more potent and selective PPARγ ligands with a low toxicity profile, thereby reducing unwanted side effects.

Multi-ancestry Genome-Wide Association Meta-Analysis Identifies Novel Loci in Atopic Dermatitis

Atopic dermatitis (AD) is a highly heritable and common inflammatory skin condition affecting children and adults worldwide. Multi-ancestry approaches to AD genetic association studies are poised to boost power to detect genetic signal and identify ancestry-specific loci contributing to AD risk. Here, we present a multi-ancestry GWAS meta-analysis of twelve AD cohorts from five ancestral populations totaling 56,146 cases and 602,280 controls. We report 101 genomic loci associated with AD, including 15 loci that have not been previously associated with AD or eczema. Fine-mapping, QTL colocalization, and cell-type enrichment analyses identified genes and cell types implicated in AD pathophysiology. Functional analyses in keratinocytes provide evidence for genes that could play a role in AD through epidermal barrier function. Our study provides new insights into the etiology of AD by harnessing multiple genetic and functional approaches to unveil the mechanisms by which AD-associated variants impact genes and cell types.

Comparative Proteomics Analysis Reveals Distinct Molecular Phenotype and Biomarkers in Patients with Erythrodermic Atopic Dermatitis and Erythrodermic Psoriasis

Erythrodermic atopic dermatitis (EAD) and erythrodermic psoriasis (EP) are rare yet debilitating inflammatory skin disorders that propose challenges in diagnosis and discovering effective therapeutic targets. Despite their clinical and histological similarities, the underlying molecular mechanisms and systemic biomarkers of these diseases are substantially unclear. In this study, we sought to investigate the differential serum proteome of EP and EAD patients and identify biomarkers for these two subtypes of erythroderma. We recruited 14 EAD patients, 14 EP patients and 14 healthy controls. Serum samples were collected and analyzed using the Olink high-throughput platform to assess the levels of 269 inflammation-/immune response-/cardiovascular-related biomarkers. Both EAD and EP patients exhibited enhanced immune activation and dysregulated cardiovascular profiles compared to healthy controls. EAD demonstrated a more pronounced inflammation tone, characterized by Th1/Th2/Th22/IL-1-dominant patterns, as well as increased TNF superfamily, Th17, and apoptosis markers. Conversely, EP displayed inflammation with Th1/Th17/TNF-skewing and mild Th2 upregulation, along with notable increases in epidermal-development markers. Disease severity in EAD was strongly correlated with apoptosis/Th2 markers, while correlated with Th17 markers in EP. Furthermore, a panel of eight markers (IL-17A/IL-17C/PI3/CCL20/SH2D1A/SIRT2/DFFA/IL-13) was identified that effectively discriminated between EP and EAD, with an Area Under the Curve greater than 0.8. Our study comprehensively characterizes the circulating molecular profiles in EAD and EP patients, providing insights into the similarities and complexities of their inflammation phenotypes. The identified serum biomarkers have the potential to differentiate between EP and EAD, which could aid in the diagnosis and guiding tailored therapeutics.

Randomized double-blind placebo-controlled cosmetic trial of a topical first-in-class Neutraligand targeting the chemokine TARC/CCL17 in mild-to-moderate atopic dermatitis

BACKGROUND

Atopic dermatitis has a marked economic impact and affects the quality of life. A cosmetic compound with an innovative strategy is proposed here as a small chemical neutraligand, GPN279 (previously identified as a theophylline derivative), that binds and potently neutralizes the TARC/CCL17 chemokine, activating the Th2 cell-expressed CCR4 receptor.

OBJECTIVE

Our objective was to evaluate the safety and activity of topically applied GPN279 in mild-to-moderate atopic dermatitis patients in a randomized, double-blind, placebo-controlled, parallel group trial. Such cosmetic active ingredient targeting dry skin with an atopic tendency would open a parallel strategy to the pharmaceutical approach, in particular for mild to moderate subjects, as an alternative to reduce the evolution towards severe forms of atopy.

METHODS

This 4-week trial included adults with mild-to-moderate atopic dermatitis, according to the SCORAD index. Patients were randomized into two groups treated by topical applications of either an emulsion containing 0.44% GPN279 in placebo on skin lesions or the placebo (4.56% glycerin). Clinical activity was evaluated with the SCORAD as the primary objective. As secondary objectives, POEM, erythema, skin moisturization, its barrier function (TEWL) and safety were evaluated.

RESULTS

Twenty-one patients in each group completed the study. SCORAD was significantly improved in the GPN279 group vs. placebo. GPN279 also significantly improved POEM, induced a rapid and significant decrease of erythema, and improved skin moisture. GPN279 and placebo were well tolerated throughout the study.

CONCLUSION

A cosmetic cream comprising the CCL17 neutraligand GPN279 improved the skin barrier and physiology criteria in patients with mild-to-moderate atopic dermatitis.

Hand Sanitizer: Stopping the Spread of Infection at a Cost

The recent rise in hand sanitizer use due to the COVID-19 pandemic has had a beneficial impact on stopping the spread of disease, but the potential negative implications of its overuse on the body and the microbiome have yet to be thoroughly reviewed. Epidermal layers absorb hand sanitizer from direct application to the skin, making them some of the most susceptible cells to the adverse effects of overuse. The increased usage of hand sanitizer can affect the variation, quantity, and diversity of the skin microflora, leading to conditions such as eczema, atopic dermatitis, and even systemic toxicity due to colonization of the skin with pathogenic bacteria. Due to the close-knit relationship between the skin and gut, the gastrointestinal system can also incur disruptions due to the negative effects on the skin as a result of excessive hand sanitizer use, leading to gut dysbiosis. Additionally, the accidental ingestion of hand sanitizer, and its abuse or misuse, can be toxic and lead to alcohol poisoning, which is an issue most commonly seen not only in the pediatric population but also in adolescents and adults due to aberrant recreational exposure. As a vulnerable body system, the eyes can also be negatively impacted by hand sanitizer misuse leading to chemical injury, visual impairment, and even blindness. In this review, we aim to highlight the variations in hand sanitizer formulation, the benefits, and how misuse or overuse may lead to adverse effects on the skin, gut, and eyes. In particular, we review the advantages and disadvantages of alcohol-based hand sanitizers (ABHSs) and non-alcohol-based hand sanitizers (NABHSs) and how the components and chemicals used in each can contribute to organ dysbiosis and systemic damage.

Basophils are important for development of allergic skin inflammation

BACKGROUND

Atopic dermatitis skin lesions exhibit increased infiltration by basophils. Basophils produce IL-4, which plays an important role in the pathogenesis of atopic dermatitis.

OBJECTIVE

We sought to determine the role of basophils in a mouse model of antigen-driven allergic skin inflammation.

METHODS

Wild-type mice, mice with selective and inducible depletion of basophils, and mice expressing Il4-driven enhanced green fluorescent protein were subjected to epicutaneous sensitization with ovalbumin or saline. Sensitized skin was examined by histology for epidermal thickening. Cells were analyzed for surface markers and intracellular expression of enhanced green fluorescent protein by flow cytometry. Gene expression was evaluated by real-time reverse transcription-quantitative PCR.

RESULTS

Basophils were important for epidermal hyperplasia, dermal infiltration by CD4+ T cells, mast cells, and eosinophils in ovalbumin-sensitized mouse skin and for the local and systemic TH2 response to epicutaneous sensitization. Moreover, basophils were the major source of IL-4 in epicutaneous-sensitized mouse skin and promote the ability of dendritic cells to drive TH2 polarization of naive T cells.

CONCLUSION

Basophils play an important role in the development of allergic skin inflammation induced by cutaneous exposure to antigen in mice.

Efficacy and safety of purslane (Portulaca oleracea) for mild to moderate chronic hand eczema; A randomized, double-blind, placebo-controlled clinical trial

INTRODUCTION

Chronic hand eczema (CHE) is a common skin inflammation with a complex pathophysiology. Due to its anti-inflammatory properties, Portulaca oleracea L. (purslane) is traditionally used in Persian medicine for skin ailments. This study aimed to evaluate the safety and efficacy of a standardized purslane extract (based on traditional Persian medicine) for adults with mild or moderately severe CHE.

METHODS

A randomized, double-blind, placebo-controlled clinical trial was conducted at Razi Hospital in Iran from January to June 2022. Participants were randomly allocated to receive an oral purslane or placebo syrup plus topical Vaseline for four weeks. Seventy participants were randomly allocated into the intervention (n = 35) and placebo (n = 35) groups. The primary outcomes were the extent and severity of CHE symptoms over the four weeks after adjusting for age, gender and baseline score. Secondary outcomes were quality of life, symptom recurrence, treatment satisfaction, and adverse events.

RESULTS

After 4 weeks of treatment, compared to the placebo group (n = 31), the purslane group (n = 31) had significantly lower physician-reported fissure scores (adjusted mean difference (adjMD): -0.50, 95 %CI -3.93 to -0.34, p = 0.043), participant-reported itching (adjMD -0.51, 95 %CI -2.32 to -0.31, p = 0.041), dryness (adjMD -1.46, 95 %CI -2.89 to -0.03, p = 0.045), and total itching, dryness and thickness (adjMD -2.36, 95 %CI -6.23 to -1.51, p = 0.023) scores. Fourteen participants (purslane n = 10; placebo n = 4, p = 0.068) experienced adverse events of mild to moderate severity.

CONCLUSION

Purslane has some promising effects for reducing the extent and severity of CHE symptoms, and no direct comparisons have been made with commonly used treatments. Future multicenter trials and mechanistic studies are warranted to establish the safety and effectiveness of purslane as a potential therapeutic agent for CHE.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (IRCT20200707048040N1).

Neonatal Vitamin D and Associations with Longitudinal Changes of Eczema up to 25 Years of Age

BACKGROUND

Early-life vitamin D is a potentially modifiable risk factor for the development of eczema, but there is a lack of data on longitudinal associations.

METHOD

We measured 25(OH)D3 levels from neonatal dried blood spots in 223 high-allergy-risk children. Latent class analysis was used to define longitudinal eczema phenotype up to 25 years (4 subclasses). Skin prick tests (SPTs) to 6 allergens and eczema outcomes at 6 time points were used to define eczema/sensitization phenotypes. Associations between 25(OH)D3 and prevalent eczema and eczema phenotypes were assessed using logistic regression models.

RESULTS

Median 25(OH)D3 level was 32.5 nmol/L (P25-P75 = 23.1 nmol/L). Each 10 nmol/L increase in neonatal 25(OH)D3 was associated with a 26% reduced odds of early-onset persistent eczema (adjusted multinomial odds ratio (aMOR) = 0.74, 95% CI = 0.56-0.98) and 30% increased odds of early-onset-resolving eczema (aMOR = 1.30, 95% CI = 1.05-1.62) when compared to minimal/no eczema up to 12 years. Similar associations were seen for eczema phenotype up to 25 years. We did not see any strong evidence for the association between neonatal 25(OH)D3 and prevalent eczema or eczema/sensitization phenotype.

CONCLUSIONS

Higher neonatal 25(OH)D3 levels, a reflection of maternal vitamin D levels in pregnancy, may reduce the risk of early-onset persistent eczema.

Liposome-Hydrogel Composites for Controlled Drug Delivery Applications

Various controlled delivery systems (CDSs) have been developed to overcome the shortcomings of traditional drug formulations (tablets, capsules, syrups, ointments, etc.). Among innovative CDSs, hydrogels and liposomes have shown great promise for clinical applications thanks to their cost-effectiveness, well-known chemistry and synthetic feasibility, biodegradability, biocompatibility and responsiveness to external stimuli. To date, several liposomal- and hydrogel-based products have been approved to treat cancer, as well as fungal and viral infections, hence the integration of liposomes into hydrogels has attracted increasing attention because of the benefit from both of them into a single platform, resulting in a multifunctional drug formulation, which is essential to develop efficient CDSs. This short review aims to present an updated report on the advancements of liposome-hydrogel systems for drug delivery purposes.

Potential Aspects of the Use of Cytokines in Atopic Dermatitis

Atopic dermatitis (AD) is an abnormal inflammatory response in the skin to food, environmental IgE, or non-IgE allergens. This disease belongs to a group of inflammatory diseases that affect both children and adults. In highly developed countries, AD is diagnosed twice as often in children than in adults, which may possibly be connected to increased urbanization. The immune system's pathomechanisms of AD involve humoral mechanisms with IgE, cellular T lymphocytes, dendritic cells occurring in the dermis, Langerhans cells occurring in the epidermis, and other cells infiltrating the site of inflammation (eosinophils, macrophages, mast cells, neutrophils, and basophils). Cytokines are small proteins that affect the interaction and communication between cells. This review characterizes cytokines and potential aspects of the treatment of atopic dermatitis, as well as new strategies that are currently being developed, including targeting cytokines and their receptors.

Papulovesicular Riddle in an Atopic Individual

Atopic dermatitis (AD) characterized by pruritus and eczematous lesions makes individuals susceptible to various viral and bacterial infections. Eczema herpeticum (EH), also known as Kaposi's varicelliform eruption, is a severe herpes simplex virus infection that can be observed in individuals with AD. EH manifests with monomorphic vesicles and "punched-out" erosions accompanied by hemorrhagic crusts, primarily affecting eczematous areas. Misdiagnosis, often as impetigo, can lead to severe complications and even death. Timely diagnosis and treatment with acyclovir are crucial to avert these outcomes. Here we present a case of a 19-year-old male with AD who presented with a monomorphic vesicular rash.

Association between atopic disease and vaccination granulomas: A nested case-control study

BACKGROUND

Vaccination granulomas are observed in 1% of all children vaccinated with an aluminium-adsorbed vaccine. Most children with granulomas also have aluminium contact allergy (CA). CA and atopic diseases are both highly prevalent among children and may be associated.

OBJECTIVE

To investigate the association between vaccination granulomas and atopic dermatitis (AD), asthma and rhinitis in children.

METHODS

We sourced a cohort of all Danish children born from 2009 to 2017 and conducted a nested case-control study, with cases defined as children with vaccination granulomas, matched to controls 1:10 on sex, socioeconomic class, gestational age and season of birth. All cases and controls were vaccinated with aluminium-adsorbed vaccines and followed until their second birthday. We used conditional logistic regression to estimate the odds ratios (ORs).

RESULTS

The study included 2171 cases with vaccination granulomas, and 21 710 controls. Children with a diagnosis of AD had a significantly higher risk of a vaccination granuloma (OR 1.50, 95% confidence intervals [CI] 1.25-1.80). No significant association was found between granulomas and asthma or rhinitis. The association between granulomas and AD was even higher in an additional sensitivity-analysis, following the children until their fourth birthday (OR 2.71, 95% CI 2.36-3.11).

CONCLUSION

AD was significantly associated with vaccination granulomas, but not with other atopic diseases, within both the first 2 and 4 years of life.

Cannabinoids for the treatment of autoimmune and inflammatory skin diseases: A systematic review

In recent years, the medical use of cannabinoids has attracted growing attention worldwide. In particular, anti-inflammatory properties of cannabinoids led to their emergence as potential therapeutic options for autoimmune and inflammatory disorders. Recent studies have also shown that cannabinoid receptors are widely expressed and have endogenous ligands in the skin, suggesting that the skin has its own endocannabinoid system. The aim of this review is to discuss the potential therapeutic effects of cannabinoids in autoimmune and inflammatory skin diseases. Following an overview of cannabinoids and the endocannabinoid system, we describe the cellular and molecular mechanisms of cannabinoids in skin health and disease. We then review the clinical studies of cannabinoids in autoimmune and inflammatory skin diseases including systemic sclerosis (SSc), dermatomyositis (DM), psoriasis (Pso) and atopic dermatitis (AD). A primary literature search was conducted in July 2023, using PubMed and Web of Science. A total of 15 articles were included after excluding reviews, non-human studies and in vitro studies from 389 non-duplicated articles. Available evidence suggests that cannabinoids may be beneficial for SSc, DM, Pso and AD. However, further studies, ideally randomized controlled trials, are needed to further evaluate the use of cannabinoids in autoimmune and inflammatory skin diseases.

A Staphylococcus epidermidis strain inhibits the uptake of Staphylococcus aureus derived from atopic dermatitis skin into the keratinocytes

BACKGROUND

Various bacterial species form a microbiome in the skin. In the past, dead Staphylococcus aureus derived from atopic dermatitis (AD) are taken up by keratinocytes; however, whether live S. aureus can be taken up by keratinocytes is unknown.

OBJECTIVE

This study aimed to examine whether live AD strains of S. aureus internalize into the keratinocytes and how the internalization changes under conditions in which other bacterial species including S. epidermidis are present.

METHODS

HaCaT cells were cultured with live S. aureus and S. epidermidis (live or heat-treated) or their culture supernatants. After coculture, the change in the amount of S. aureus in the cytoplasm of HaCaT cells was analyzed using, a high-throughput imaging system, Opera Phenix™.

RESULTS

Live S. aureus were taken up in the cytoplasm of HaCaT cells. Coculturing live S. aureus with live S. epidermidis or the culture supernatants decreased the abundance of S. aureus in the cytoplasm. The heat-treated culture supernatants of live S. epidermidis or culture supernatants of other S. strains did not decrease the abundance of S. aureus in the cytoplasm.

CONCLUSION

Live S. aureus was internalized into the cytoplasm of HaCaT cells as does heat-treated S. aureus. In addition, the heat-sensitive substances secreted by coculture with S. epidermidis and keratinocytes inhibited the uptake of S. aureus by keratinocytes.

Decreased skin colonization with Malassezia spp. and increased skin colonization with Candida spp. in patients with severe atopic dermatitis

Background

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease in which patients are sensitized towards a plethora of allergens. The hosts fungal microbiota, the mycobiota, that is believed to be altered in patients suffering from AD acts as such an allergen. The correlation context of specific sensitization, changes in mycobiota and its impact on disease severity however remains poorly understood.

Objectives

We aim to enhance the understanding of the specific sensitization towards the mycobiota in AD patients in relation to their fungal skin colonization.

Methods

Sensitization pattern towards the Malassezia spp. and Candida albicans of 16 AD patients and 14 healthy controls (HC) were analyzed with the newly developed multiplex-assay ALEX2® and the established singleplex-assay ImmunoCAP®. We compared these findings with the fungal skin colonization analyzed by DNA sequencing of the internal transcribed spacer region 1 (ITS1).

Results

Sensitization in general and towards Malassezia spp. and C. albicans is increased in AD patients compared to HC with a quantitative difference in severe AD when compared to mild to moderate AD. Further we saw an association between sensitization towards and skin colonization with Candida spp. yet a negative correlation between sensitization towards and skin colonization with Malassezia spp.

Conclusion

We conclude that AD in general and severe AD in particular is associated with increased sensitization towards the hosts own mycobiota. There is positive correlation in Candida spp. skin colonization and negative in Malassezia spp. skin colonization when compared to AD, AD severity as well as to specific sensitization patterns.

Anti-inflammatory effects of neuregulin-1 in HaCaT keratinocytes and atopic dermatitis-like mice stimulated with Der p 38

Neuregulin (NRG)-1 plays fundamental roles in several organ systems after binding to its receptors, ErbB2 and ErbB4. This study examines the role of NRG-1 in atopic dermatitis (AD), a chronic skin disease that causes dryness, pruritus, and inflammation. In mice administered Der p 38, the skin presents AD-like symptoms including filaggrin downregulation and infiltration of neutrophils and eosinophils. Noticeably, there is an increased expression of NRG-1, ErbB2, and ErbB4 in the skin. Upregulation of these proteins is significantly correlated to the clinical skin severity score. In human keratinocyte HaCaT cells, exposure to Der p 38 decreased filaggrin expression, and NRG-1 alone had no effect on the expression. However, co-treatment of Der p 38 with NRG-1 enhanced the filaggrin expression decreased by Der p 38. Pre-treatment with AG879 (an ErbB2 inhibitor) or ErbB4 siRNA blocked the recovery of filaggrin expression in the cells after co-treatment with Der p 38 and NRG-1. Der p 38 treatment enhanced the secretion of interleukin-6 (IL-6), IL-8, and monocyte chemoattractant protein-1 (MCP-1). Co-treatment of Der p 38 with NRG-1 lowered the cytokine secretion increased by Der p 38, although NRG-1 alone was not effective on cytokine alteration. Neutrophil apoptosis was not altered by NRG-1 or supernatants of cells treated with NRG-1, but the cell supernatants co-treated with Der p 38 and NRG-1 blocked the anti-apoptotic effects of Der p 38-treated supernatants on neutrophils, which was involved in the activation of caspase 9 and caspase 3. Taken together, we determined that NRG-1 has anti-inflammatory effects in AD triggered by Der p 38. These results will pave the way to understanding the functions of NRG-1 and in the future development of AD treatment.

Characterization of T-Helper Immune Phenotype in Symmetrical Drug-Related Intertriginous and Flexural Exanthema (SDRIFE) Endorses a Delayed-Type Hypersensitivity Reaction

ABSTRACT

Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) is a cutaneous drug eruption with a characteristic distribution of erythema on the gluteal/inguinal region and intertriginous areas with unclear pathogenesis. In this study, we aimed to characterize the T-helper immune phenotype in SDRIFE in comparison with psoriasis and eczema to further the understanding of the pathophysiology and immune response of this rare disorder. Immunohistochemical staining was performed on 9 skin biopsies each from SDRIFE, psoriasis, and eczema using immunohistochemistry for CD3 and dual CD4/T-bet, CD4/GATA3, and CD4/RORC to quantify the percentage of Th1, Th2, and Th17 cells, respectively. A significant difference was detected in the average percentage of Th1 between all 3 groups with the highest percentage of Th1 cells seen in psoriasis, followed by SDRIFE and eczema. SDRIFE showed significantly lower Th2 expression as compared to both psoriasis and eczema. There was a trend towards a higher average percentage of Th17 in psoriasis and SDRIFE, and the ratio of Th17:Th2 was significantly higher in samples of SDRIFE compared with both eczema and psoriasis. The findings characterize SDRIFE as a Th1 and possibly Th17-driven process, which could inform future therapeutic options and substantiate the model of SDRIFE as a delayed-type hypersensitivity reaction.

Emerging Role of the IL-36/IL-36R Axis in Multiple Inflammatory Skin Diseases

IL-36 is a most recent member of the IL-1 cytokine family, primarily expressed at barrier sites of the body such as the skin, lungs, and intestine. It plays a vital role in inflammation and is implicated in the development of various cutaneous; intestinal; and pulmonary disorders, including psoriasis, inflammatory bowel disease, and chronic obstructive pulmonary disease. IL-36 comprises 4 isoforms: the proinflammatory IL-36α, IL-36β, and IL-36γ and the anti-inflammatory IL-36R antagonist. An imbalance between proinflammatory and anti-inflammatory IL-36 isoforms can contribute to the inflammatory fate of cells and tissues. IL-36 cytokines signal through an IL-36R heterodimer mediating their function through canonical signaling cacade, including the NF-B pathway. Prominent for its role in psoriasis, IL-36 has recently been associated with disease mechanisms in atopic dermatitis, hidradenitis suppurativa, neutrophilic dermatoses, autoimmune blistering disease, and Netherton syndrome. The major cutaneous source of IL-36 cytokines is keratinocytes, pointing to its role in the communication between the epidermis, innate (neutrophils, dendritic cells) immune system, and adaptive (T helper [Th]1 cells, Th17) immune system. Thus, cutaneous IL-36 signaling is crucial for the immunopathological outcome of various skin diseases. Consequently, the IL-36/IL-36R axis has recently been recognized as a promising drug target for the treatment of inflammatory disorders beyond psoriasis. This review summarizes the current update on IL-36 cytokines in inflammatory skin diseases.

Phenotypes, endotypes and genotypes of atopic dermatitis and allergy in populations of African ancestry on the continent and diaspora

Atopic dermatitis is a complex inflammatory condition characterized by synergist interactions between epidermal and immune related genotypes, skin barrier defects and immune dysregulation as well as microbial dysbiosis. Ethnicity-specific variations in clinical presentation, immune endotypes and genetic susceptibility have been described in diverse populations. We summarize available data with specific consideration of AD in populations of African ancestry. Some highlights include the observation of AD lesions on extensor surfaces, lichen planus-like AD, prurigo type AD and follicular AD in African populations. In addition, a consistent absence of dominant filaggrin gene defects has been reported. The detection of normal filaggrin protein content in AD skin implicates the contribution of alternative mechanisms in the pathogenesis of AD in African patients. Markedly high IgE has been described in paediatric and adult African AD. While Th2, Th22 and Th17 activation in African AD skin shares the same direction as with other populations, it has been noted that the magnitude of activation is dissimilar. Reduced Th17 cytokines have been observed in the circulation of moderate to severe paediatric AD.

Heat shock protein 90 inhibition attenuates inflammation in models of atopic dermatitis: a novel mechanism of action

Background

Heat shock protein 90 (HSP90) is an important chaperone supporting the function of many proinflammatory client proteins. Recent studies indicate HSP90 inhibition may be a novel mechanism of action for inflammatory skin diseases; however, this has not been explored in atopic dermatitis (AD).

Objectives

Our study aimed to investigate HSP90 as a novel target to treat AD.

Methods

Experimental models of AD were used including primary human keratinocytes stimulated with cytokines (TNF/IFNγ or TNF/IL-4) and a mouse model established by MC903 applications.

Results

In primary human keratinocytes using RT-qPCR, the HSP90 inhibitor RGRN-305 strongly suppressed the gene expression of Th1- (TNF, IL1B, IL6) and Th2-associated (CCL17, CCL22, TSLP) cytokines and chemokines related to AD. We next demonstrated that topical and oral RGRN-305 robustly suppressed MC903-induced AD-like inflammation in mice by reducing clinical signs of dermatitis (oedema and erythema) and immune cell infiltration into the skin (T cells, neutrophils, mast cells). Interestingly, topical RGRN-305 exhibited similar or slightly inferior efficacy but less weight loss compared with topical dexamethasone. Furthermore, RNA sequencing of skin biopsies revealed that RGRN-305 attenuated MC903-induced transcriptome alterations, suppressing genes implicated in inflammation including AD-associated cytokines (Il1b, Il4, Il6, Il13), which was confirmed by RT-qPCR. Lastly, we discovered using Western blot that RGRN-305 disrupted JAK-STAT signaling by suppressing the activity of STAT3 and STAT6 in primary human keratinocytes, which was consistent with enrichment analyses from the mouse model.

Conclusion

HSP90 inhibition by RGRN-305 robustly suppressed inflammation in experimental models mimicking AD, proving that HSP90 inhibition may be a novel mechanism of action in treating AD.

Atopic Dermatitis Disease Complications

This chapter will describe infectious complications of atopic dermatitis, including bacterial, viral, and fungal infections and the evolving understanding of the relationship between atopic dermatitis and infectious disease. The underlying immunological dysregulation and poor skin barrier function associated with atopic dermatitis not only increase the likelihood of infectious complications but also lend atopic dermatitis skin vulnerable to flares induced by environmental triggers. Thus, this chapter will also highlight the impact of common external environmental agents on precipitating flares of disease. Lastly, this chapter will discuss complications that can arise from treatments and the association of atopic dermatitis with more serious conditions such as lymphoma.

An updated systematic review and meta-analysis of efficacy and safety of Chinese herbal medicine for treating atopic dermatitis

BACKGROUND

This systematic review evaluated the Chinese herbal medicine (CHM) for treating atopic dermatitis (AD).

METHODS

PubMed, EMBASE, the Cochrane library, the Wanfang database, and China National Knowledge Infrastructure (CNKI) were searched for relevant randomized controlled trials (RCTs) from inception to December 2021. Overall recovery rate, disease/symptom severity scoring, quality of life (QoL), recurrence rate, and incidence of adverse events (AEs) were evaluated. STATA SE 14.0 software was used for statistical analysis.

RESULTS

17 RCTs involving 1624 patients were eligible. CHM was associated with a higher overall recovery rate (risk ratio [RR] = 1.15, 95% confidence interval [CI]: 1.05, 1.26, p = .003) and decreased recurrence rate (odds ratio [OR] = 0.19, 95% CI: 0.07, 0.55, p = .002), both confirmed by sensitivity analyses. CHM could decrease scoring atopic dermatitis index (MD = -0.61, 95% CI: -1.12, -0.11, p = .017), however, sensitivity analysis revealed non-robustness. No significant differences were found between the CHM and the control group in Eczema Area and Severity Index, QoL, and the incidence of AEs.

CONCLUSIONS

CHM was effective for treating AD as it could improve the overall recovery rate and decrease the recurrence rate. More studies are required to validate the potential of CHM on disease/symptoms severity and QoL.

Infective endocarditis associated with atopic dermatitis

Infective endocarditis caused by atopic dermatitis is common in young patients and has a high potential for causing embolism. Because of the high risk of mediastinitis postoperatively, minimally invasive cardiac surgery could be effective.