Deep intronic founder mutations identified in the ERCC4/XPF gene are potential therapeutic targets for a high-frequency form of xeroderma pigmentosum.

Xeroderma pigmentosum (XP) is a genodermatosis defined by cutaneous photosensitivity with an increased risk of skin tumors because of DNA repair deficiency. The worldwide prevalence of XP is ~1 to 4 in million, with higher incidence in some countries and regions including Japan (1 in 22,000) and North Africa due to founder mutations and a high degree of consanguinity. Among XP, the complementation group F (XP-F), is a rare form (1% of worldwide XP); however, this is underdiagnosed, because the ERCC4/XPF gene is essential for fetal development and most of previously reported ERCC4/XPF pathogenic variants are hypomorphs causing relatively mild phenotypes. From the largest Japanese XP cohort study, we report 17 XP-F cases bearing two pathogenic variants, both identified in deep intronic regions of the ERCC4/XPF gene. The first variant, located in intron 1, is a Japanese founder mutation, which additionally accounts for ~10% of the entire Japanese XP cases (MAF = 0.00196), causing an aberrant pre-mRNA splicing due to a miss-binding of U1snRNA. The second mutation located in intron eight induces an alternative polyadenylation. Both mutations cause a reduction of the ERCC4/XPF gene expression, resulting in XP clinical manifestations. Most cases developed early-onset skin cancers, indicating that these variants need critical attention. We further demonstrate that antisense oligonucleotides designed for the mutations can restore the XPF protein expression and DNA repair capacity in the patients' cells. Collectively, these pathogenic variants can be potential therapeutic targets for XP.

Efficacy and safety of nemolizumab and topical corticosteroids for prurigo nodularis: Results from a randomised, double-blind, placebo-controlled, phase II/III clinical study in patients aged ≥13 years.

BACKGROUND: Prurigo nodularis, a chronic inflammatory skin condition, adversely affects the quality of life of affected individuals. Current treatment options for prurigo nodularis in Japan are limited. OBJECTIVES: To evaluate the optimal dose, efficacy, and safety of long-term treatment with nemolizumab in patients with prurigo nodularis in Japan. METHODS: In a 16-week, double-blind, phase II/III study, patients aged ≥13 years with prurigo nodularis were randomly assigned (1:1:1) to nemolizumab 30 mg, 60 mg, or placebo groups, with concomitant topical corticosteroids, every 4 weeks. The primary efficacy end point was the percentage change in the weekly mean Peak Pruritus Numerical Rating Scale (PP-NRS) score (range, 0 to 10, with higher scores indicating worse itching) from baseline to week 16. Secondary efficacy end points assessed the impact of treatment on pruritus, prurigo nodularis severity, sleep, and quality of life. RESULTS: At week 16, the least-squares mean percentage change from baseline in the PP-NRS score was -61·1% in the nemolizumab 30 mg group (n = 77), -56·0% in the 60 mg group (n = 76), and -18·6% in the placebo group (n = 76). Differences between both nemolizumab groups and placebo were significant; the difference between the 30 mg and placebo groups was -42·5% (95% confidence interval [CI], -51·9 to -33·1; P<0·0001), and between the 60 mg and placebo groups was -37·4% (95% CI, -46·7 to -28·1; P<0·0001). Nemolizumab-treated patients also had greater improvements in the number and severity of prurigo nodules, and in sleep and quality of life compared with the placebo group. Both nemolizumab doses were well tolerated. CONCLUSIONS: Improvements in prurigo nodularis were greater following nemolizumab treatment, despite continuation of topical corticosteroids in both groups. (Funded by Maruho; jRCT number, 2011200017.).

[RECOMMENDATION FOR ITCH ASSESSMENT FROM THE ATOPIC ITCH CONSENSUS MEETING (AICOM)].

BACKGROUND: Itch is the most troublesome symptom of atopic dermatitis, and it is important to assess it appropriately for optimal treatment. We discussed issues regarding itch and the most appropriate methods of assessment at the Atopic Itch Consensus Meeting (AICOM), attended by physicians and researchers with expertise in itch treatment and research. METHODS: The AICOM participants prepared a draft consensus statement that addressed the most appropriate itch assessment methods for age groups <2 years, 2-6 years, 7-14 years, and ≥15 years. Consensus was defined as agreement by ≥80% of the participants. RESULTS: Votes were cast by 20 participants (8 dermatologists, 7 pediatricians, and 5 researchers), and a consensus on the best current methods of itch assessment was reached with 95% agreement. For infants and preschool children, because subjective evaluation is difficult, a checklist for itch assessment was developed for caregivers. CONCLUSION: For itch assessment, we recommend subjective evaluation by the patient using a rating scale. For infants and preschoolers, evaluation should be done by the caregiver using a checklist, combined with objective evaluation (of skin lesions, for example) by a physician. We anticipate that more objective itch assessment indices will be established in the future.

Immune complexome analysis of a rich variety of serum immune complexes identifies disease-characteristic immune complex antigens in systemic sclerosis.

Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular endothelial dysfunction and skin fibrosis. Recently, the presence and pathogenic role of immune complexes (ICs) of SSc patients were reported. However, the identities of antigens in these ICs are unknown. Therefore, we examined ICs in the serum of SSc patients to elucidate SSc pathogenesis. In this study, IC concentrations in serum samples from SSc and systemic lupus erythematosus (SLE) patients were measured by C1q enzyme-linked immunosorbent assays; immune complex analysis was used for comprehensive identification and comparison of antigens incorporated into ICs (IC-antigens). The expression patterns of SSc-specific IC-antigens in skin sections were investigated by immunohistochemistry. Compared with SLE patients who developed disease because of IC deposition, SSc patients had a greater number of IC-antigens and a smaller difference in IC concentrations, suggesting that SSc pathogenesis is affected by the proteins present in ICs. In contrast, the IC concentration and number of IC-antigens did not significantly differ according to the clinical phenotype of SSc. We identified 478 IC-antigens in SSc patients, including multiple RNAP II-associated proteins that were targeted by antibodies previously associated with SSc pathogenesis. The most frequently detected RNAP II-associated protein, RNA polymerase II transcription subunit 30 (MED30), was strongly expressed at lesion sites and reportedly regulates endothelial differentiation. Therefore, increased expression of MED30 in lesions may have an antigenic effect, and MED30 function may be impaired or inhibited by IC formation. RNAP II-associated proteins may SSc pathogenesis through mechanisms such as the MED30 pathway.

High frequency of HTRA1 AND ABCC6 mutations in Japanese patients with adult-onset cerebral small vessel disease.

BACKGROUND: This study aimed to clarify the frequency and clinical features of monogenic cerebral small vessel disease (mgCSVD) among patients with adult-onset severe CSVD in Japan. METHODS: This study included patients with adult-onset severe CSVD with an age of onset ≤55 years (group 1) or >55 years and with a positive family history (group 2). After conducting conventional genetic tests for NOTCH3 and HTRA1, whole-exome sequencing was performed on undiagnosed patients. Patients were divided into two groups according to the results of the genetic tests: monogenic and undetermined. The clinical and imaging features were compared between the two groups. RESULTS: Group 1 and group 2 included 75 and 31 patients, respectively. In total, 30 patients had NOTCH3 mutations, 11 patients had HTRA1 mutations, 6 patients had ABCC6 mutations, 1 patient had a TREX1 mutation, 1 patient had a COL4A1 mutation and 1 patient had a COL4A2 mutation. The total frequency of mutations in NOTCH3, HTRA1 and ABCC6 was 94.0% in patients with mgCSVD. In group 1, the frequency of a family history of first relatives, hypertension and multiple lacunar infarctions (LIs) differed significantly between the two groups (monogenic vs undetermined; family history of first relatives, 61.0% vs 25.0%, p=0.0015; hypertension, 34.1% vs 63.9%, p=0.0092; multiple LIs, 87.8% vs 63.9%, p=0.0134). CONCLUSIONS: More than 90% of mgCSVDs were diagnosed by screening for NOTCH3, HTRA1 and ABCC6. The target sequences for these three genes may efficiently diagnose mgCSVD in Japanese patients.

The detailed obstetric course of the first Japanese patient with AEBP1-related Ehlers-Danlos syndrome (classical-like EDS, type 2).

We reported a detailed obstetric course of a Japanese patient with Ehlers-Danlos syndrome (EDS) caused by biallelic pathogenic variants in the AEBP1 gene. She was diagnosed with classical EDS at 3 years of age. At 33 years, whole-exome sequencing revealed a homozygous nonsense variant (c.1894C > T:p.Arg632*) in AEBP1. This is the 10th case of AEBP1-related EDS (classical-like EDS type 2) and the first in Japan. She was managed as an inpatient at our hospital beginning at 20 weeks of gestation because of the possibility of high-risk pregnancy. She experienced painful urinary retention, migraines, and threatened premature labor. She delivered a healthy female via elective caesarean section at 32 weeks of gestation. She was treated in the intensive care unit for severe paralytic ileus, postoperatively. Conservative therapy resulted in favorable outcomes, and she was safely discharged on postdelivery day 22nd.

[JAPANESE TRANSLATION AND LINGUISTIC VALIDATION OF THE RECAP OF ATOPIC ECZEMA (RECAP)].

BACKGROUND: The Recap of atopic eczema (RECAP), a new core outcome of the atopic dermatitis trial, was translated into Japanese and linguistically validated. METHODS: Translation into Japanese was accomplished according to the ISPOR (International Society for Pharmacoeconomics and Outcome Research) guidelines and the basic guidelines for scale translation. The translation process included two forward translations, reconciliation with native English speakers, third-party back translation, cognitive debriefing, review and harmonization by the original authors. Twenty-seven atopic dermatitis and pediatric specialists from 21 centers in Japan participated in the translation process. Cognitive debriefing was conducted through face-to-face interviews using a think-aloud method with the interview guide including questions about comprehensibility, relevance, comprehensiveness, recall period and suggested improvements, based on the COSMIN methodology. RESULTS: No linguistic or cultural problems were encountered in the translation into Japanese. Cognitive debriefings were conducted with 10 adult patients and 10 parents of pediatric patients. Some minor modifications were made following discussion and approval by the research team and the original authors. The Japanese version of RECAP was considered to be understandable, comprehensive and relevant for adult patients and families of pediatric patients. CONCLUSION: The Japanese version of the RECAP, which has been validated as linguistically equivalent to the original version, is now available. Further evaluation of the measurement properties is needed in the future.

Cell surface-expressed Ro52/IgG/HLA-DR complex is targeted by autoantibodies in patients with inflammatory myopathies.

Intracellular proteins are often targeted by autoantibodies in autoimmune diseases; however, the mechanism through which intracellular molecules are targeted remains unknown. We previously found that several intracellular misfolded proteins are transported to the cell surface by HLA class II molecules and are recognized by autoantibodies in some autoimmune diseases, such as rheumatoid arthritis, antiphospholipid syndrome, and microscopic polyangiitis. Ro52 is an intracellular Fc receptor that is a target antigen for myositis-associated autoantibodies. We analyzed the role of HLA class II molecules in the autoantibody recognition of Ro52. Ro52 alone was not transported to the cell surface by HLA class II molecules; however, it was transported to the cell surface in the presence of both IgG heavy chain and HLA class II molecules to form a Ro52/IgG/HLA-DR complex. The Ro52/IgG/HLA-DR complex was specifically recognized by autoantibodies from some patients with inflammatory myopathies. We then evaluated 120 patients with inflammatory myopathies with four types of myositis-specific antibodies and analyzed the autoantibodies against the Ro52/IgG/HLA-DR complex. The specific antibodies against the Ro52/IgG/HLA-DR complex were detected in 90% and 93% of patients who were positive for anti-MDA5 and anti-ARS antibodies, respectively. In individual patients with these two inflammatory myopathies, changes in serum titers of anti-Ro52/IgG/HLA-DR-specific antibodies were correlated with the levels of KL-6 (R = 0.51 in anti-MDA5 antibody-positive DM patients, R = 0.67 in anti-ARS antibody-positive PM/DM patients with respiratory symptoms) and CK (R = 0.63 in anti-ARS antibody-positive PM/DM patients with muscle symptoms) over time. These results suggest that antibodies against Ro52/IgG/HLA-DR expressed on the cell surface could be involved in the pathogenesis of inflammatory myopathy subgroups.

Clinical Course of Atopic Dermatitis in an Adult with Amyotrophic Lateral Sclerosis: Aetiological Implications of Voluntary Movements and Dermatitis Severity.

is missing (Short communication).

Exacerbating factors and disease burden in patients with atopic dermatitis.

The number of patients with atopic dermatitis is on the rise worldwide, and Japan is no exception. According to recent estimates of the percentage of patients with atopic dermatitis in Japan by age, the majority of patients are between 20 and 44 years old. Because the peak age of onset of atopic dermatitis is during infancy, many patients may experience prolonged symptoms from infancy to adulthood. A prolonged clinical course also increases the burden of atopic dermatitis on affected patients. Decreased productivity due to work disruptions, reduced daily activity, higher direct medical costs, fatigue, and daytime sleepiness due to sleep disturbances are typical burdens on patients with atopic dermatitis. In order to reduce these burdens, it is necessary to shorten its clinical course and achieve long-term control without relying on medications, possibly by using avoidance or coping measures of aggravating factors. Typical aggravating factors of atopic dermatitis include irritant dermatitis, food allergy in children, sweating, and psychological stress in adults. Food allergy places a heavy burden on the quality of life of affected patients and their families. The effectiveness of educational interventions for sweating and psychological stress is unclear. We must also evaluate the economic burden and cost-effectiveness of interventions on the patient as aggravating factors to be addressed.

Executive summary: Japanese guidelines for atopic dermatitis (ADGL) 2021.

This is an abridged edition of English version of the Clinical Practice Guidelines for the Management of Atopic Dermatitis 2021. Atopic dermatitis (AD) is a disease characterized by relapsing eczema with pruritus as a primary lesion. In Japan, from the perspective of evidence-based medicine, the current strategies for the treatment of AD consist of three primary measures: (i) use of topical corticosteroids, tacrolimus ointment, and delgocitinib ointment as the main treatment of the inflammation; (ii) topical application of emollients to treat the cutaneous barrier dysfunction; and (iii) avoidance of apparent exacerbating factors, psychological counseling, and advice about daily life. In the present revised guidelines, the description about three new drugs, namely, dupilumab, delgocitinib, and baricitinib, has been added. The guidelines present recommendations to review clinical research articles, evaluate the balance between the advantages and disadvantages of medical activities, and optimize medical activity-related patient outcomes with respect to several important points requiring decision-making in clinical practice.

Expression of histidine decarboxylase in melanocytes of the human skin.

Histamine-producing cells include storage-type cells (e.g., mast cells and basophils), which store histamine intracellularly, and inducible-type cells (e.g., keratinocytes and macrophages), which induce histidine decarboxylase (HDC, a key enzyme for histamine biosynthesis) activity but do not have a storage pool of histamine. Most of the studies focused on identifying HDC-expressing cells by using cultured cells, and few on investigating the localization of HDC by using skin tissues. Hence, this study conducted immunohistochemical studies using human healthy skin samples. HDC-positive and cytokeratin 14 (a marker of basal keratinocytes)-negative cells were present around the basal layer of the epidermis. These cells did not immunohistochemically react with mast cell tryptase but expressed tyrosinase (a key enzyme for melanin biosynthesis) and microphthalmia-associated transcription factor (MITF, a transcription factor controlling the expression of tyrosinase genes). Melanin granules were clearly observed around HDC-positive and MITF-positive cells. Moreover, HDC mRNA and protein were both detected in cultured normal human epidermal melanocytes. In conclusion, HDC-positive and cytokeratin 14-negative cells around the basal layer of the epidermis are melanocytes.

Anti-pruritic effect of nemolizumab in hemodialysis patients with uremic pruritus: a phase II, randomized, double-blind, placebo-controlled clinical study.

BACKGROUND: The pathophysiology of uremic pruritus (UP), which is characterized by systemic and intractable itching, remains unclear. As interleukin (IL)-31 may be involved, we conducted a phase II, randomized, controlled study to evaluate nemolizumab (anti-IL-31 receptor A antibody) in Japanese hemodialysis patients with UP. METHODS: Patients were randomly assigned (1:1:1:1:1) to one of four double-blind groups (receiving a single subcutaneous injection of nemolizumab 0.125, 0.5, or 2.0 mg/kg, or placebo on Day 1) or an open-label reference group (receiving oral nalfurafine hydrochloride 2.5-5 µg once daily for 12 weeks). The primary endpoint was the difference in the absolute change in pruritus visual analog scale (VAS) at Week 4 between placebo and each nemolizumab group. RESULTS: The primary efficacy endpoint was not met. The mean change from baseline with all three nemolizumab doses at Week 1, and with 0.5 mg/kg at Week 4, was greater than with placebo. Least square mean differences (95% confidence intervals) in the absolute changes between the placebo arm and each nemolizumab arm were - 2.4 (- 19.7, 14.9) for 0.125 mg/kg, - 8.7 (- 26.6, 9.2) for 0.5 mg/kg, and 0.4 (- 17.0, 17.8) for 2.0 mg/kg. Secondary efficacy parameters including the Shiratori severity score and 5-D itch score failed to show between-group differences. Patients with higher serum IL-31 levels at screening tended to have greater pruritus VAS reductions following nemolizumab treatment. CONCLUSIONS: In this phase II study in patients with UP, the primary efficacy parameter was not met. Nemolizumab was generally well tolerated with no clinically significant safety concerns. CLINICAL TRIAL REGISTRATION: JAPIC: JapicCTI-152961, https://www.clinicaltrials.jp/cti-user/trial/ShowDirect.jsp?japicId=JapicCTI-152961 .

Factors associated with the development of oral allergy syndrome: A retrospective questionnaire survey of Japanese university students.

BACKGROUND: Oral allergy syndrome (OAS) is an IgE-mediated food allergy. Ingestion of causative antigens leads to the development of local symptoms such as numbness of the oral mucosa in most cases and anaphylaxis in a few cases. The prevalence of OAS including in healthy people has not been investigated. Thus, we conducted a questionnaire survey of Japanese university students. METHODS: We conducted a cross-sectional study of 2688 first-year students using a questionnaire survey in marksheet format and examined the epidemiological characteristics of OAS. RESULTS: Only 2.7% of students were aware of the term "oral allergy syndrome". A total of 143 (5.3%) students had OAS. There were significant associations between OAS and other allergic diseases including allergic rhinitis (AR) (OR: 3.8, 95% CI: 2.7-5.5), atopic dermatitis (AD) (OR: 4.6, 95%CI: 3.3-6.6), and bronchial asthma (BA) (OR: 3.0, 95%CI: 2.0-4.5). The onset age of OAS showed bimodal peaks at 0 and 10 years, and the latter peak coincided with the peak onset age of AR. CONCLUSIONS: Awareness of OAS was low in our study, which will make it difficult to treat properly and prevent its development. This survey confirmed the association between OAS and other allergic diseases, especially AR, which suggests that OAS is involved in the allergic march. A novel finding was that sensitization to antigens for OAS occurred around the same time as sensitization to antigens for AR. These results will help medical professionals diagnose OAS and develop lifestyle guidelines to prevent OAS-related symptoms such as anaphylaxis.

Insight into innate immune response in "Yusho": The impact of natural killer cell and regulatory T cell on inflammatory prone diathesis of Yusho patients.

BACKGROUND: In 1968 in western Japan, polychlorinated biphenyl-contaminated "Kanemi rice oil" was used in cooking, causing food poisoning in many people. More than 50 years have passed since the Yusho incident, and although inflammatory disorders such as suppuration have been observed in Yusho patients, the etiology of this inflammation susceptibility remains obscure. OBJECTIVES: To investigate the mechanisms of susceptibility to inflammation in Yusho patients, peripheral immune cell fractions and concentrations of inflammatory cytokines were evaluated in blood samples collected from both Yusho patients and age-matched healthy subjects undergoing medical examination in Nagasaki. METHODS: To exclude diagnostic uncertainty, serum levels of polychlorinated biphenyl (PCB), polychlorinated quarterphenyl (PCQ), and polychlorinated dibenzofuran (PCDF) were measured. Immune cell (e.g. natural killer and regulatory T cell) populations were analyzed by flow cytometry. Serum cytokines involved in immune cell activation were measured by ELISA. RESULTS: The relative proportion of natural killer cells was higher in Yusho patients than in healthy subjects, while the proportion of regulatory T cells did not differ between groups. Serum concentrations of IL-36 and IFN-γ were significantly lower in Yusho patients than in healthy subjects. Conversely, serum cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), which is a cytokine related to activated NK cells, was higher in Yusho patients than in healthy subjects and was positively correlated with PCDF blood levels. CONCLUSION: Increased numbers of NK cells in Yusho patients suggests that the innate immune response has been activated in Yusho patients. The seemingly paradoxical results for CTLA-4 and IFN-γ may reflect counterbalancing mechanisms preventing excessive NK cell activation. This dysregulation of innate immunity might contribute to the inflammation observed in Yusho patients.

Skin Mycobiome of Psoriasis Patients is Retained during Treatment with TNF and IL-17 Inhibitors.

BACKGROUND: Biological treatment relieves refractory skin lesions in patients with psoriasis; however, changes in the fungal microbiome (the mycobiome) on the skin are unclear. METHODS: The skin mycobiome of psoriasis patients treated with TNF inhibitors (TNFi, n = 5) and IL-17 inhibitors (IL-17i, n = 7) was compared with that of patients not receiving systemic therapy (n = 7). Skin swab samples were collected from non-lesional post-auricular areas. Fungal DNA was sequenced by ITS1 metagenomic analysis and taxonomic classification was performed. RESULTS: An average of 37543 reads/sample were analyzed and fungi belonging to 31 genera were detected. The genus Malassezia accounted for >90% of reads in 7/7 samples from the no-therapy group, 4/5 from the TNFi group, and 5/7 from the IL-17i group. Biodiversity was low in those three groups. Few members of the genus trichophyton were detected; the genus Candida was not detected at all. Among the Malassezia species, M. restricta was the major species in 6/7 samples from the no-therapy group, 4/5 from the TNFi group, and 5/7 from the IL-17i group whose the other largest species revealed M. globosa. CONCLUSIONS: The mycobiome is retained on post-auricular skin during systemic treatment with TNF and IL-17 inhibitors.

Consensus statements on pediatric atopic dermatitis from dermatology and pediatrics practitioners in Japan: Goals of treatment and topical therapy.

BACKGROUND: Pediatric atopic dermatitis (PAD) is a pluricausal disease and is frequently seen in dermatological and pediatric practice. Therefore, it is important to find common views in clinical practice and to promote consensus among practitioners. Aiming to obtain common views among dermatologists and pediatricians and to disseminate them widely in clinical practice, we held the PAD Consensus Forums described herein. METHODS: Questionnaire surveys of treatment goals and drug therapy were conducted to prepare topics for discussion at the PAD Consensus Forums. Reaching consensus was defined as agreement among at least 70% of the participants. RESULTS: As a result of discussion among 24 dermatologists and 25 pediatricians, consensus was obtained on 7 topics. These topics configure 3 consensus of treatment goals (Attainment targets were divided into the short/medium term and the long term. Attainment targets were associated with the primary evaluation domains of the Harmonising Outcome Measures for Eczema (HOME) roadmap, etc.) and 4 consensus of drug therapy (The number of applications of topical anti-inflammatory drugs in the acute phase and selection and ideal intervals between applications of topical anti-inflammatory drugs in proactive therapy, etc.). CONCLUSIONS: The consensus is expected to help practitioners set appropriate treatment goals in clinical practice and facilitate the choice of drugs for treatment.

Japanese guidelines for atopic dermatitis 2020.

Atopic dermatitis (AD) is a disease characterized by relapsing eczema with pruritus as a primary lesion, which is frequently encountered in clinical practice. Skin barrier dysfunction leads to enhanced skin irritability to non-specific stimuli and epicutaneous sensitization. In the lesion site, a further inflammation-related reduction in skin barrier function, enhanced irritability and scratching-related stimuli deteriorate eczema, leading to vicious cycle of inflammation. The current strategies to treat AD in Japan from the perspective of evidence-based medicine consist of three primary measures: (i) the use of topical corticosteroids and tacrolimus ointment as the main treatment for the inflammation; (ii) topical application of emollients to treat the cutaneous barrier dysfunction; and (iii) avoidance of apparent exacerbating factors, psychological counseling and advice about daily life. The guidelines present recommendations to review clinical research articles, evaluate the balance between the advantages and disadvantages of medical activities, and optimize medical activity-related patient outcomes with respect to several important points requiring decision-making in clinical practice.

Why does sweat lead to the development of itch in atopic dermatitis?

Sweating plays an important role in maintaining temperature homeostasis in humans. However, under certain circumstances, sweat can cause itching. For example, when excessive sweat accumulates on the skin surface for a long period, miliaria can develop and cause itching. Subjects with dermatoses, such as atopic dermatitis (AD), suffer from itch when exposed to heat or psychological stresses, which are also known perspiration stimuli. Recently, some mechanisms of sweat-induced itch have been revealed. For instance, attenuated sweating ability is observed in subjects with AD, causing heat retention, skin dryness, and high susceptibility to itch. Furthermore, the decreased tight junction of the sweat gland in AD leads to sweat leakage in the dermis, which could be designated as a "sweat endocrine response" and may be the cause of tingling itch during sweating. Additionally, metabolomic analysis of sweat from patients with AD revealed that glucose concentration in sweat increases according to disease severity. Sweat with elevated glucose concentration retards the recovery of the damaged skin barrier and may promote itching. This viewpoint essay outlines the relationship between sweat and itch based on recent evidence.

Involvement of Periostin in Skin Function and the Pathogenesis of Skin Diseases.

Skin is a large organ that is susceptible to damage by external forces, chronic inflammation, and autoimmune reactions. In general, tissue damage causes alterations in both the configuration and type of cells in lesional skin. This phenomenon, called tissue remodeling, is a universal biological response elicited by programmed cell death, inflammation, immune disorders, and tumorigenic, tumor proliferative, and cytoreductive activity. During this process, changes in the components that comprise the extracellular matrix are required to provide an environment that facilitates tissue remodeling. Among these extracellular matrix components, periostin (a glycoprotein secreted predominantly by dermal fibroblasts) has attracted much attention. In normal skin, periostin localizes mainly in the papillary dermis and basement membrane of the epidermis. However, it is expressed at higher levels in the dermis of lesional skin of those with atopic dermatitis, scars, systemic/limited scleroderma, melanoma, and cutaneous T cell lymphoma; expression is also increased by damage caused by allergic/autoimmune responses. Furthermore, periostin induces processes that result in development of dermal fibrosis; it also activates or protracts the immune response. The aim of this review is to summarize recent knowledge about the role of periostin in the pathogenesis of dermatoses.