Hidehisa Saeki

Guidelines for management of atopic dermatitis.

Atopic dermatitis (AD) is a chronic relapsing eczematous skin disease characterized by pruritus and inflammation and accompanied by cutaneous physiological dysfunction (dry and barrier‐disrupted skin). Most of the patients have atopic diathesis. A standard guideline for the management (diagnosis, severity classification and therapy) of AD has been established. In our guideline, the necessity of dermatological training is emphasized in order to assure diagnostic skill and to enable evaluation of the severity of AD. The definitive diagnosis of AD requires the presence of all three features: (i) pruritus; (ii) typical morphology and distribution; and (iii) chronic and chronically relapsing course. For the severity classification of AD, three elements of eruption (erythema/acute papules, exudation/crusts and chronic papules/nodules/lichenification) are evaluated in the most severely affected part of each of the five body regions (head/neck, anterior trunk, posterior trunk, upper limbs and lower limbs). The areas of eruption on the five body regions are also evaluated, and both scores are totaled (maximum 60 points). The present standard therapies for AD consist of the use of topical corticosteroids and tacrolimus ointment as the main treatment for the inflammation, topical application of emollients to treat the cutaneous physiological dysfunction, systemic antihistamines and anti‐allergic drugs as adjunctive treatments for pruritus, avoidance of apparent exacerbating factors, psychological counseling and advice about daily life. Tacrolimus ointment (0.1%) and its low‐density ointment (0.03%) are available for adult patients and 2–15‐year‐old patients, respectively. The importance of the correct selection of topical corticosteroids according to the severity of the eruption is also emphasized. Furthermore, deliberate use of oral cyclosporine for severe recalcitrant adult AD is referred.

Interleukin-12 p40 gene (IL12B) 3'-untranslated region polymorphism is associated with susceptibility to atopic dermatitis and psoriasis vulgaris.

Interleukin-12 (IL-12) is believed to play an important role in inducing Th1-type cytokine profiles. Atopic dermatitis (AD) and psoriasis vulgaris (PsV) are considered to be Th2 and Th1 type disease, respectively. The IL-12 p40 subunit gene (IL12B) is located at chromosome 5q31-33 and linkage findings of AD on 5q31 were reported. Recently single nucleotide polymorphism (SNP) (1188A/C) of IL12B has been reported. In function, it has been reported that this SNP is associated with IL12B mRNA expression levels. To learn whether this SNP is associated with susceptibility to AD or PsV, we investigated the genotype and allele frequencies of the SNP in AD patients, in PsV patients and in controls, examining 164 AD patients, 143 PsV patients and 100 healthy individuals in Japanese population. Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. The A allele was decreased in AD patients (40.9%, p = 0.031) and increased in PsV patients (60.1%, p = 0.035) compared with controls (50.5%). This suggests that IL12B SNP is associated with susceptibility to AD and PsV, presumably by affecting the Th1/Th2 balance.

Genome-wide association study identifies eight new susceptibility loci for atopic dermatitis in the Japanese population.

Atopic dermatitis is a common inflammatory skin disease caused by interaction of genetic and environmental factors. On the basis of data from a genome-wide association study (GWAS) and a validation study comprising a total of 3,328 subjects with atopic dermatitis and 14,992 controls in the Japanese population, we report here 8 new susceptibility loci: IL1RL1-IL18R1-IL18RAP (Pcombined = 8.36 × 10−18), the major histocompatibility complex (MHC) region (P = 8.38 × 10−20), OR10A3-NLRP10 (P = 1.54 × 10−22), GLB1 (P = 2.77 × 10−16), CCDC80 (P = 1.56 × 10−19), CARD11 (P = 7.83 × 10−9), ZNF365 (P = 5.85 × 10−20) and CYP24A1-PFDN4 (P = 1.65 × 10−8). We also replicated the associations of the FLG, C11orf30, TMEM232-SLC25A46, TNFRSF6B-ZGPAT, OVOL1, ACTL9 and KIF3A-IL13 loci that were previously reported in GWAS of European and Chinese individuals and a meta-analysis of GWAS for atopic dermatitis. These findings advance the understanding of the genetic basis of atopic dermatitis.

Fractalkine, a CX3C chemokine, is expressed by dendritic cells and is up‐regulated upon dendritic cell maturation

The lone CX3C chemokine, fractalkine (FK), is expressed in a membrane‐bound form on activated endothelial cells and mediates attachment and firm adhesion of T cells, monocytes and NK cells. We now show that FK is associated with dendritic cells (DC) in epidermis and lymphoid organs. In normal human skin, dual‐color fluorescence microscopy co‐localized FK expression with Langerhans cells expressing CD1a. In tonsil, FK‐positive DC expressed CD83, a marker for mature DC. Human and murine cultured DC up‐regulated FK mRNA expression with maturation. Furthermore, CD40 ligation, but not TNF‐α or lipopolysaccharide treatment, of activated, migratory DC that had migrated from skin explants resulted in a 2.5‐fold increase of surface expression of FK without significant alterations of expression of CD80, CD86, CD54 or MHC class II. Since FK mediates adhesion of T cells to activated endothelial cells, the increased expression of FK during DC maturation (and particularly by CD40 ligation) may play a role in the ability of T cells and mature DC to form conjugates and engage in cell‐cell communication.

Serum macrophage-derived chemokine (MDC) levels are closely related with the disease activity of atopic dermatitis

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease characterized by the predominant infiltration of T cells, eosinophils and macrophages in lesional skin. Recently, macrophage‐derived chemokine (MDC)/CCL22, a CC chemokine, was identified as a selective chemoattractant for CC chemokine receptor 4 (CCR4)‐expressing cells, in addition to thymus and activation‐regulated chemokine (TARC). We have previously reported that serum TARC levels correlate with the severity of AD. In this report, we investigated the participation of MDC in AD. First, we measured serum MDC levels in 45 patients with AD, 25 patients with psoriasis vulgaris and 25 healthy controls. Serum MDC levels in AD patients were significantly higher than those in healthy controls and psoriasis patients. Furthermore, the increases in serum MDC levels in AD patients were greater in the severely affected group than in the moderate or mild groups. We compared serum MDC levels in 11 AD patients, before and after treatment, and observed a significant decrease after treatment. Moreover, the serum MDC levels significantly correlated with the Scoring AD (SCORAD) index, serum soluble (s) E‐selectin levels, serum soluble interleukin‐2 receptor (sIL‐2R) levels, serum TARC levels and eosinophil numbers in peripheral blood. Our study strongly suggests that serum MDC levels have a notable correlation with disease activity and that MDC, as well as the CC chemokine TARC, may be involved in the pathogenesis of AD.

Towards global consensus on outcome measures for atopic eczema research: results of the HOME II meeting

The use of nonstandardized and inadequately validated outcome measures in atopic eczema trials is a major obstacle to practising evidence‐based dermatology. The Harmonising Outcome Measures for Eczema (HOME) initiative is an international multiprofessional group dedicated to atopic eczema outcomes research. In June 2011, the HOME initiative conducted a consensus study involving 43 individuals from 10 countries, representing different stakeholders (patients, clinicians, methodologists, pharmaceutical industry) to determine core outcome domains for atopic eczema trials, to define quality criteria for atopic eczema outcome measures and to prioritize topics for atopic eczema outcomes research. Delegates were given evidence‐based information, followed by structured group discussion and anonymous consensus voting. Consensus was achieved to include clinical signs, symptoms, long‐term control of flares and quality of life into the core set of outcome domains for atopic eczema trials. The HOME initiative strongly recommends including and reporting these core outcome domains as primary or secondary endpoints in all future atopic eczema trials. Measures of these core outcome domains need to be valid, sensitive to change and feasible. Prioritized topics of the HOME initiative are the identification/development of the most appropriate instruments for the four core outcome domains. HOME is open to anyone with an interest in atopic eczema outcomes research.

Significant elevation of serum levels of eotaxin-3/CCL26, but not of eotaxin-2/CCL24, in patients with atopic dermatitis: serum eotaxin-3/CCL26 levels reflect the disease activity of atopic dermatitis

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease characterized by the predominant infiltration of T cells, eosinophils and macrophages in lesional skin. Recently, eotaxin‐2/CCL24 and eotaxin‐3/CCL26 were identified as CC chemokines that signal exclusively via the CCR3 receptor and have eosinophil‐selective chemoattractant activity, as does eotaxin/CCL11. We previously reported that serum levels of thymus and activation‐regulated chemokine (TARC)/CCL17 and macrophage‐derived chemokine (MDC)/CCL22 were correlated with the severity of AD. In this report, we investigated the participation of eotaxin‐2/CCL24 and eotaxin‐3/CCL26 in AD, first measuring the serum levels of eotaxin‐2/CCL24 and eotaxin‐3/CCL26 in 30 patients with AD, 20 patients with psoriasis vulgaris and 20 healthy controls. The serum levels of eotaxin‐3/CCL26 (but not eotaxin‐2/CCL24) were significantly higher in patients with AD than in either healthy controls or patients with psoriasis vulgaris; furthermore, the eotaxin‐3/CCL26 levels in patients with moderate and severe AD were significantly higher than eotaxin‐3/CCL26 levels in patients with mild AD. The serum eotaxin‐3/CCL26 levels tended to decrease after treatment, but there was no significant difference between groups. Moreover, the serum eotaxin‐3/CCL26 levels were significantly correlated with the serum TARC/CCL17 and MDC/CCL22 levels, eosinophil numbers in peripheral blood and the scoring AD (SCORAD) index. Our study strongly suggests that serum levels of eotaxin‐3/CCL26, but not of eotaxin‐2/CCL24, have a notable correlation with disease activity of AD and that eotaxin‐3/CCL26, as well as TARC/CCL17 and MDC/CCL22, may be involved in the pathogenesis of AD.

Interleukin-13 gene polymorphism G4257A is associated with atopic dermatitis in Japanese patients

Interleukin (IL)-13 plays an important role in the induction of immunoglobulin E (IgE) and in the pathogenesis of atopic dermatitis (AD). We investigated the allele and genotype frequencies of three IL-13 single nucleotide polymorphisms (SNPs) (A704C and C1103T in the promoter region and G4257A in exon 4) in Japanese patients with AD. For A704C and C1103T SNPs, there were no significant differences in allele or genotype frequencies between AD patients and controls. For G4257A SNP, A allele was significantly increased in AD patients (39.5%) compared with controls (29.4%) (P = 0.016). The same proportion of each genotype and allele was observed in the patient subgroup with and without asthma. Serum IgE levels and peripheral eosinophil counts were not significantly different among genotypes in G4257A SNP. There was also no significant difference in allele or genotype frequencies between AD patients with mild disease and those with severe disease, between those with family history of AD and those without it, or between those with family history of atopic disorders and those without it. This result suggests that 4257A allele is associated with susceptibility to AD and that it may function in the pathogenesis of AD itself, presumably by other mechanisms than inducing IgE production.

A migratory population of skin-derived dendritic cells expresses CXCR5, responds to B lymphocyte chemoattractant in vitro, and co-localizes to B cell zones in lymph nodes in vivo.

Chemokine receptors on dendritic cells (DC) and chemokines within lymph nodes (LN) contribute to trafficking of DC to appropriate sites within the LN. Here we show that DC that have migrated out of skin ex vivo (migratory DC, migDC) express 50‐fold more CXCR5 mRNA than fresh Langerhans cells and migrate in response to B lymphocyte chemoattractant (BLC) in vitro. When injected into the footpad of mice, migDC emigrate to regional LN where up to 40 % are found in B cell zones. By contrast, murine bone marrow‐derived DC display 14‐fold less CXCR5, do not migrate to BLC in vitro, and migrate strictly to T cell zones in LN. We propose that activated skin DC utilize CXCR5 and BLC as a possible mechanism to home to B cell zones of LN, where they may have direct effects on B cells.

Clinical Practice Guidelines for the Management of Atopic Dermatitis 2016.

Atopic dermatitis (AD) is a disease characterized by relapsing eczema with pruritus as a primary lesion. Most patients have an atopic predisposition. The definitive diagnosis of AD requires the presence of all three features: (i) pruritus; (ii) typical morphology and distribution of the eczema; and (iii) chronic and chronically relapsing course. 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.