Toll-like receptors: their roles in pathomechanisms of atopic dermatitis.

The skin functions as a physical barrier and represents the first line of the innate immune system. There is increasing evidence that toll-like receptors (TLRs) are involved in the pathomechanisms of not only infectious diseases, but also non-infectious inflammatory diseases. Interestingly, it has been demonstrated that TLRs recognize both exogenous threats, e.g. bacteria and viruses, and endogenous danger signals related to inflammation, cell necrosis, or tissue damage. Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease, which is associated with impaired skin barrier function, increased skin irritability to non-specific stimuli, and percutaneous sensitization. The impairment of skin barrier function in AD allows various stimuli, such as potential allergens and pathogens, to penetrate the skin and activate the innate immune system, including TLR signaling, which can lead to the development of adaptive immune reactions. In this review, I summarize the current understanding of the roles of TLR signaling in the pathogenesis of AD, with special emphasis on skin barrier function and inflammation.

Efficacy of Integrated Online Mindfulness and Self-compassion Training for Adults With Atopic Dermatitis: A Randomized Clinical Trial.

Importance: Quality of life (QOL) of patients with atopic dermatitis (AD) is reported to be the lowest among skin diseases. To our knowledge, mindfulness and self-compassion training has not been evaluated for adults with AD. Objective: To evaluate the efficacy of mindfulness and self-compassion training in improving the QOL for adults with AD. Design, Setting, and Participants: This randomized clinical trial conducted from March 2019 through October 2022 included adults with AD whose Dermatology Life Quality Index (DLQI) score, a skin disease-specific QOL measure, was greater than 6 (corresponding to moderate or greater impairment). Participants were recruited from multiple outpatient institutes in Japan and through the study's social media outlets and website. Interventions: Participants were randomized 1:1 to receive eight 90-minute weekly group sessions of online mindfulness and self-compassion training or to a waiting list. Both groups were allowed to receive any dermatologic treatment except dupilumab. Main Outcomes and Measures: The primary outcome was the change in the DLQI score from baseline to week 13. Secondary outcomes included eczema severity, itch- and scratching-related visual analog scales, self-compassion and all of its subscales, mindfulness, psychological symptoms, and participants' adherence to dermatologist-advised treatments. Results: The study randomized 107 adults to the intervention group (n = 56) or the waiting list (n = 51). The overall participant mean (SD) age was 36.3 (10.5) years, 85 (79.4%) were women, and the mean (SD) AD duration was 26.6 (11.7) years. Among participants from the intervention group, 55 (98.2%) attended 6 or more of the 8 sessions, and 105 of all participants (98.1%) completed the assessment at 13 weeks. The intervention group demonstrated greater improvement in the DLQI score at 13 weeks (between-group difference estimate, -6.34; 95% CI, -8.27 to -4.41; P < .001). The standardized effect size (Cohen d) at 13 weeks was -1.06 (95% CI, -1.39 to -0.74). All secondary outcomes showed greater improvements in the intervention group than in the waiting list group. Conclusions and Relevance: In this randomized clinical trial of adults with AD, integrated online mindfulness and self-compassion training in addition to usual care resulted in greater improvement in skin disease-specific QOL and other patient-reported outcomes, including eczema severity. These findings suggest that mindfulness and self-compassion training is an effective treatment option for adults with AD. Trial Registration: https://umin.ac.jp/ctr Identifier: UMIN000036277.

Topical Betamethasone Treatment of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis with Ocular Involvement in the Acute Phase.

PURPOSE: To clarify the importance of administering topical steroids for the treatment of Stevens-Johnson syndrome (SJS) / toxic epidermal necrolysis (TEN) with ocular involvement in the acute phase. DESIGN: Retrospective case series. METHODS: Using the medical records of acute SJS/TEN patients treated at the Kyoto Prefectural University of Medicine Hospital, Kyoto, Japan, between July 2006 and July 2017, the ocular findings, topical steroid dosage, systemic steroid dosage, and ocular sequelae were retrospectively examined. The level of cytokines in tear fluid and serum samples was also analyzed. RESULTS: This study involved 13 cases. In 10 cases in whom the clinical courses were recorded before the start of steroid therapy, the mean acute ocular severity score (AOSS: 3 = very severe; 2 = severe; 1 = mild; 0 = none) was 2.8 ± 0.4 points in the severest phase. The mean systemic steroid dose after steroid pulse therapy was 694 ± 386 mg and the mean topical steroid (0.1% betamethasone eye drop and ointment) dose was 13.4 ± 3.3 times daily in the severest phase. Analysis of cytokine levels of 4 cases showed that a cytokine storm occurred in the tear fluid after the steroid pulse therapy. At final follow-up, 16 eyes of 8 patients had a logMAR visual acuity of ≤0, and no serious ocular sequelae were observed. CONCLUSIONS: In patients with SJS/TEN, ocular surface inflammation remains strong even after systemic inflammation has improved post steroid pulse therapy, thus suggesting that both systemic and topical steroid therapy should be administered appropriately.

Enhanced early skin treatment for atopic dermatitis in infants reduces food allergy.

BACKGROUND: Early-onset atopic dermatitis is a strong risk factor for food allergy, suggesting that early effective treatment may prevent transcutaneous sensitization. OBJECTIVES: This study tested whether enhanced treatment of atopic dermatitis to clinically affected and unaffected skin is more effective in preventing hen's egg allergy than reactive treatment to clinically affected skin only. METHODS: This was a multicenter, parallel-group, open-label, assessor-blind, randomized controlled trial (PACI [Prevention of Allergy via Cutaneous Intervention] study). This study enrolled infants 7-13 weeks old with atopic dermatitis and randomly assigned infants in a 1:1 ratio to enhanced early skin treatment or conventional reactive treatment using topical corticosteroids (TCSs). The primary outcome was the proportion of immediate hen's egg allergy confirmed by oral food challenge at 28 weeks of age. RESULTS: This study enrolled 650 infants and analyzed 640 infants (enhanced [n = 318] or conventional [n = 322] treatment). Enhanced treatment significantly reduced hen's egg allergy compared with the conventional treatment (31.4% vs 41.9%, P = .0028; risk difference: -10.5%, upper bound of a 1-sided CI: -3.0%), while it lowered body weight (mean difference: -422 g, 95% CI: -553 to -292 g) and height (mean difference: -0.8 cm, 95% CI: -1.22 to -0.33 cm) at 28 weeks of age. CONCLUSIONS: This study highlighted the potential of well-controlled atopic dermatitis management as a component of a hen's egg allergy prevention strategy. The enhanced treatment protocol of this trial should be modified before it can be considered as an approach to prevent hen's egg allergy in daily practice to avoid the adverse effects of TCSs. After remission induction by TCSs, maintenance therapy with lower potency TCSs or other topical therapies might be considered as alternative proactive treatments to overcome the safety concerns of TCSs.

Exploratory analyses of biomarkers in blood and stratum corneum in patients with atopic dermatitis.

BACKGROUND: The pathogenesis of atopic dermatitis (AD) involves various mediators, including cytokines and chemokines, which are produced by immune cells, such as dendritic cells and lymphocytes, and non-immune cells, such as epidermal cells. Several mediators, including thymus and activation-regulated chemokine (TARC), are used as biomarkers for AD severity and activity. However, additional local and systemic biomarkers of AD are required. METHODS: This study will include 10 male patients with AD and 5 healthy adult males (age range: 20-80 years). The Eczema Area and Severity Index will be used to objectively evaluate the clinical findings. In addition, the severity of eruptions will be assessed on a 5-point scale by scoring symptoms (erythema, edema/papules, oozing/crusting, excoriation, lichenification, and xerosis), and the total intensity will be calculated by adding the symptom scores together. Subjective symptoms will be assessed using a peak pruritus numerical rating scale. Laboratory tests, including measurements of peripheral eosinophil count and serum total immunoglobulin E, TARC, and lactate dehydrogenase levels, will be performed. Using blood samples and extracts of stratum corneum samples obtained by tape stripping, we will conduct an exploratory analysis of protein expression using an antibody array to identify mediators whose levels are significantly altered in patients with AD. After 4 to 8 weeks, blood samples and stratum corneum samples will be collected again from AD patients. Moreover, we will examine whether the candidate proteins can be quantified using enzyme-linked immunosorbent assays. DISCUSSION: This is an important study exploring potential local and systemic biomarkers of AD. The results of this study will be clinically meaningful for the discovery of new biomarkers for diagnosing and assessing the severity of AD.

Increased plasma miR-24 and miR-191 levels in patients with severe atopic dermatitis: Possible involvement of platelet activation.

BACKGROUND: Platelets are involved in the pathomechanisms of atopic dermatitis (AD). This study aimed to elucidate the levels of platelet-related miRNAs, (miR-24 and miR-191) in the plasma of AD patients and their relationships with the disease severity and laboratory data. METHODS: miRNAs were detected in the subjects plasma using specifically primed quantitative reverse transcription polymerase chain reaction. RESULTS: The patients with severe AD had significantly higher plasma miR-24 or miR-191 levels than the patients with mild AD, the urticaria patients, and the healthy volunteers. The plasma miR-24 and miR-191 levels of the AD patients were correlated with their serum thymus and activation-regulated chemokine levels. In addition, plasma miR-24 and miR-191 levels were correlated with their plasma levels of platelet factor 4 and ß-thromboglobulin. CONCLUSION: Our findings imply that miR-24 and miR-191 may be involved in the pathomechanisms responsible for the worsening of AD, possibly through their effects on platelet activation.

Patch testing with the Japanese baseline series 2015: A 4-year experience.

BACKGROUND: The Japanese baseline series (JBS), established in 1994, was updated in 2008 and 2015. The JBS 2015 is a modification of the thin-layer rapid-use epicutaneous (TRUE) test (SmartPractice Denmark, Hillerød, Denmark). No nationwide studies concerning the TRUE test have previously been reported. OBJECTIVES: To determine the prevalence of sensitizations to JBS 2015 allergens from 2015 to 2018. METHODS: We investigated JBS 2015 patch test results using the web-registered Skin Safety Care Information Network (SSCI-Net) from April 2015 to March 2019. RESULTS: Patch test results of 5865 patients were registered from 63 facilities. The five allergens with the highest positivity rates were gold sodium thiosulfate (GST; 25.7%), nickel sulfate (24.5%), urushiol (9.1%), p-phenylenediamine (PPD; 8.9%), and cobalt chloride (8.4%). The five allergens with the lowest positivity rates were mercaptobenzothiazole (0.8%), formaldehyde (0.9%), paraben mix (1.1%), mercapto mix (1.1%), and PPD black rubber mix (1.4%). CONCLUSIONS: Nickel sulfate and GST had the highest positivity rates. The JBS 2015, including a modified TRUE test, is suitable for baseline series patch testing.

Positive regulation of innate immune response by miRNA-let-7a-5p.

Background: We have hypothesized that different factors are involved in the severity of ACD and AD because some but not all patients with atopic dermatitis (AD) present with allergic conjunctival disease (ACD) including severe types such as atopic keratoconjunctivitis (AKC) with/without giant papillae. We previously reported that plasma miR-628-3p was up-regulated in AD with severe ACD, but not in severe AD without severe ACD or in our healthy controls. In this study, to investigate the pathogenesis of AD with and without severe ACD, we performed comprehensive plasma miRNA analysis and studied the function of some miRNAs which were significantly up-regulated in ACD. Methods: Transcriptomics analysis of miRNA was performed using the microarray platform from the plasma of nine individuals (AD, severe ACD, controls: n = 3 each). To confirm up-regulation of the 12 miRNAs of the eight miRNA groups we focused on, we performed quantitative miRNA polymerase chain reaction (PCR) assays using 80 plasma samples (AD: 23, severe ACD: 17, controls: 40). To study the function of the eight miRNAs which were significantly up-regulated in ACD, we transfected their mimic to THP-1 cells, a monocyte cell line, and performed comprehensive gene expression analysis of them. The up-regulation of gene expression of interest in transfected THP-1 cells with the hsa-let-7a-5p miRNA mimic was confirmed by quantitative RT-qPCR assay. Results: Quantitative miRNA PCR assays showed that hsa-let-7a-5p, hsa-let-7days-3p, hsa-let-7e-5p, and hsa-miR-151a-5p were significantly up-regulated in both AD-ACD + and AD-ACD - as were hsa-miR-130a-3p, hsa-miR-151a-3p, has-miR-27b-3p, and hsa-miR-146a-5p in AD-ACD + but not in AD-ACD - . The functions of each miRNA were investigated by comprehensive gene expression analysis of THP-1 cells transfected with each miRNA mimic. Of the eight miRNAs, hsa-let-7a-5p, hsa-let-7e-5p, has-miR-27b-3p, and hsa-miR-146a-5p mimic-transfected THP-1 cells showed the up-regulation of CXCL10 (IP-10; interferon gamma-induced protein 10), which might be one of the innate immune-related genes. Quantitative RT-qPCR assays of transfected THP-1 cells with the hsa-let-7a-5p miRNA mimic showed that the 17 genes up-regulated more than 10-fold in the comprehensive gene expression analysis, and TLR3, RIG-I, and MDA5, important innate immune-related genes, were significantly up-regulated. TNFSF13B, AIM2, USP41, STAP1, GBP4, CCL8, and IFI27, reportedly down-regulated by the hsa-miR-628-3p mimic, were also significantly up-regulated in the transfected cells. Conclusion: Hsa-let-7a-5p, which was significantly up-regulated in AD-ACD + and AD-ACD - , could positively regulate the important innate immune-related genes such as TLR3, RIG-I, and MDA5. It is possible that in an allergic disease such as atopic keratoconjunctivitis and/or dermatitis, innate immune responses might be positively regulated by hsa-let-7a-5p in the plasma.

Effects of constant light exposure on allergic and irritant contact dermatitis in mice reared under constant light conditions.

Environmental light levels can affect physiological functions, such as general activity, body temperature and metabolism. Irregular lifestyles, such as those involving exposure to light during the night, can exacerbate the clinical symptoms of several inflammatory skin diseases. However, the effects of constant light exposure on immune responses are not fully understood. This study aimed to elucidate the effects of constant light exposure on two major types of skin reactions, allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD). BALB/c mice were kept under constant light conditions or a normal light and dark cycle, and their ACD and ICD responses were assessed after the topical application of 2,4,6-trinitro-1-chlorobenzene and croton oil, respectively, to the ear skin. Interestingly, in both ACD and ICD, the ear-swelling response and local leukocyte infiltration were aggravated by constant exposure to light, which has previously been shown to severely disturb the behavioural rhythms of mice. In ACD, these findings were accompanied by increases in the numbers of degranulated mast cells and eosinophils. These results suggest that constant light exposure intensifies allergic and non-allergic skin inflammation.

Gender disparities in academic dermatology in Japan: Results from the first national survey.

BACKGROUND: A wide gender gap exists in many fields in Japan, including the academic society of dermatology. Women are substantially underrepresented in the highest academic ranks. OBJECTIVE: We aimed to clarify the possible factors contributing to the current gender gap in the field of academic dermatology and to recommend necessary measures to decrease the gender gap. METHODS: We performed a cross-sectional study of faculty members' academic productivity at the dermatology departments of all the educational institutions in Japan in 2019. RESULTS: Women had significantly lower academic productivity than men. A significant gender difference in academic productivity was found in lecturers and assistant professors but not in associate professor and professor positions. This gender difference was still significant after normalizing the productivity for career length. CONCLUSION: Our findings suggest the need to encourage women lecturers and assistant professors to improve their academic achievement to decrease the gender gap in academic dermatology.