Ichiro Katayama

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 60u2003points). 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.

The skin of patients with systemic sclerosis softened during the treatment with anti-IL-6 receptor antibody tocilizumab

Objective. SSc is an autoimmune disease characterized by fibrosis of the skin and internal organs. Although the aetiology remains uncertain, many reports have suggested that IL-6 is involved in SSc pathogenesis. Tocilizumab, an anti-IL-6 receptor antibody, is an anti-arthritis medicine that works through the blockade of IL-6 functions. To examine the effect of tocilizumab on SSc, we administered tocilizumab to two SSc patients. Methods. Two dcSSc patients were administered tocilizumab at 8u2009mg/kg once a month for 6 months. One patient had pulmonary fibrosis assessed by CT and spirometry, and the other had chronic renal failure caused by scleroderma renal crisis. Their skin condition was monitored with a Vesmeter and the modified Rodnan total skin score (mRTSS). Skin biopsies were obtained before and after the tocilizumab treatment to investigate the histological changes. Results. After tocilizumab treatment, both patients showed softening of the skin with reductions of 50.7 and 55.7% in the total z-score of Vesmeter hardness and 51.9 and 23.0% in the mRTSS, respectively. Histological examination showed thinning of the collagen fibre bundles in the dermis. The creatinine clearance in the patient with chronic renal failure improved from 38 to 55u2009ml/min. However, the fibrotic changes in the lung in the other patient remained unchanged. Conclusions. In the two cases of SSc that we report here, softening of the skin was observed during the treatment with tocilizumab.

A randomized double-blind trial of intravenous immunoglobulin for pemphigus

BACKGROUNDnPemphigus is a rare life-threatening intractable autoimmune blistering disease caused by IgG autoantibodies to desmogleins. It has been difficult to conduct a double-blind clinical study for pemphigus partly because, in a placebo group, appropriate treatment often must be provided when the disease flares.nnnOBJECTIVEnA multicenter, randomized, placebo-controlled, double-blind trial was conducted to investigate the therapeutic effect of a single cycle of high-dose intravenous immunoglobulin (400, 200, or 0 mg/kg/d) administered over 5 consecutive days in patients relatively resistant to systemic steroids.nnnMETHODSnWe evaluated efficacy with time to escape from the protocol as a novel primary end point, and pemphigus activity score, antidesmoglein enzyme-linked immunosorbent assay scores, and safety as secondary end points.nnnRESULTSnWe enrolled 61 patients with pemphigus vulgaris or pemphigus foliaceus who did not respond to prednisolone (> or =20 mg/d). Time to escape from the protocol was significantly prolonged in the 400-mg group compared with the placebo group (P < .001), and a dose-response relationship among the 3 treatment groups was observed (P < .001). Disease activity and enzyme-linked immunosorbent assay scores were significantly lower in the 400-mg group than in the other groups (P < .05 on day 43, P < .01 on day 85). There was no significant difference in the safety end point among the 3 treatment groups.nnnLIMITATIONnPrednisolone at 20 mg/d or more may not be high enough to define steroid resistance.nnnCONCLUSIONnIntravenous immunoglobulin (400 mg/kg/d for 5 d) in a single cycle is an effective and safe treatment for patients with pemphigus who are relatively resistant to systemic steroids. Time to escape from the protocol is a useful indicator for evaluation in randomized, placebo-controlled, double-blind studies of rare and serious diseases.

Semaphorins guide the entry of dendritic cells into the lymphatics by activating myosin II

The recirculation of leukocytes is essential for proper immune responses. However, the molecular mechanisms that regulate the entry of leukocytes into the lymphatics remain unclear. Here we show that plexin-A1, a principal receptor component for class III and class VI semaphorins, was crucially involved in the entry of dendritic cells (DCs) into the lymphatics. Additionally, we show that the semaphorin Sema3A, but not Sema6C or Sema6D, was required for DC transmigration and that Sema3A produced by the lymphatics promoted actomyosin contraction at the trailing edge of migrating DCs. Our findings not only demonstrate that semaphorin signals are involved in DC trafficking but also identify a previously unknown mechanism that induces actomyosin contraction as these cells pass through narrow gaps.

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.

Blockade of interleukin-6 receptor alleviates disease in mouse model of scleroderma.

Activation of fibroblasts by interleukin-6 (IL-6) is implicated in the pathogenesis of scleroderma, suggesting that the inhibition of fibroblast activation may be a promising scleroderma treatment. In this study, we used an IL-6 blocking antibody (Ab) and Il-6 knockout (Il-6KO) mice to examine the role of IL-6 in the bleomycin (BLM)-induced mouse model of scleroderma. BLM was administered to C57BL/6 and Il-6KO mice to induce dermal sclerosis. BLM-treated and control phosphate-buffered saline-treated mice were treated with anti-mouse IL-6 receptor monoclonal Ab (MR16-1). Disease severity was evaluated by measuring dermal thickness and skin hardness, by counting the numbers of α-smooth muscle actin-positive cells and mast cells, and by examining the cutaneous draining lymph nodes. C57BL/6 mice with BLM induced scleroderma had elevated serum IL-6 levels and more severe dermal sclerosis than Il-6KO mice. Weekly administration of MR16-1, but not control Ab, prevented and improved dermal sclerosis, and also attenuated swelling of the draining lymph nodes. MR16-1 suppressed α-smooth muscle actin induction in IL-6-stimulated Il-6KO fibroblasts. Our results indicate that IL-6 contributes to BLM induced dermal sclerosis and that IL-6 receptor-specific monoclonal Ab may improve the symptoms of scleroderma by suppressing fibroblast activation.

Periostin, a matricellular protein, accelerates cutaneous wound repair by activating dermal fibroblasts

Abstract:u2002 Cutaneous wound repair is a highly ordered and well‐coordinated process involving various cell lineages and many molecular effectors. Cell–matrix interactions through integrin molecules provide key signals important for wound repair. Periostin is a matricellular protein that may provide signals important during tissue development and remodelling by interacting with several integrin molecules, via the phosphatidylinositol 3‐kinase/Akt and MAP kinase pathways. In this study, we examined the role of periostin in the process of cutaneous wound repair using periostin‐deficient mice and by analysing the effects of periostin on dermal fibroblasts. We first determined the expression profile and localization of periostin in a well‐characterized wound repair model mice. Periostin was robustly deposited in the granulation tissues beneath the extended epidermal wound edges and at the dermal–epidermal junctions in wounded mice. Moreover, periostin‐deficient mice exhibited delayed in vivo wound repair, which could be improved by direct administration of exogenous periostin. In vitro analyses revealed that loss of periostin impaired proliferation and migration of dermal fibroblasts, but exogenous supplementation or enforced periostin expression enhanced their proliferation. Combined, these results demonstrate that periostin accelerates the process of cutaneous wound repair by activating fibroblasts.

Dysregulation of melanocyte function by Th17‐related cytokines: significance of Th17 cell infiltration in autoimmune vitiligo vulgaris

The aim of this study was to determine whether CD4+IL‐17A+Th17 cells infiltrate vitiligo skin and to investigate whether the proinflammatory cytokines related to Th17 cell influence melanocyte enzymatic activity and cell fate. An immunohistochemical analysis showed Th17 cell infiltration in 21 of 23 vitiligo skin samples in addition to CD8+ cells on the reticular dermis. An in vitro analysis showed that the expression of MITF and downstream genes was downregulated in melanocytes by treatment with interleukin (IL)‐17A, IL‐1β, IL‐6, and tumor necrosis factor (TNF)‐α. Treatment with these cytokines also induced morphological shrinking in melanocytes, resulting in decreased melanin production. In terms of local cytokine network in the skin, IL‐17A dramatically induced IL‐1β, IL‐6, and TNF‐α production in skin‐resident cells such as keratinocytes and fibroblasts. Our results provide evidence of the influence of a complex Th17 cell‐related cytokine environment in local depigmentation in addition to CD8+ cell‐mediated melanocyte destruction in autoimmune vitiligo.

Periostin Facilitates Skin Sclerosis via PI3K/Akt Dependent Mechanism in a Mouse Model of Scleroderma

Objective Periostin, a novel matricellular protein, is recently reported to play a crucial role in tissue remodeling and is highly expressed under fibrotic conditions. This study was undertaken to assess the role of periostin in scleroderma. Methods Using skin from patients and healthy donors, the expression of periostin was assessed by immunohistochemistry and immunoblotting analyses. Furthermore, we investigated periostin−/− (PN−/−) and wild-type (WT) mice to elucidate the role of periostin in scleroderma. To induce murine cutaneous sclerosis, mice were subcutaneously injected with bleomycin, while untreated control groups were injected with phosphate-buffered saline. Bleomycin-induced fibrotic changes were compared in PN−/− and WT mice by histological analysis as well as by measurements of profibrotic cytokine and extracellular matrix protein expression levels in vivo and in vitro. To determine the downstream pathway involved in periostin signaling, receptor neutralizing antibody and signal transduction inhibitors were used in vitro. Results Elevated expression of periostin was observed in the lesional skin of patients with scleroderma compared with healthy donors. Although WT mice showed marked cutaneous sclerosis with increased expression of periostin and increased numbers of myofibroblasts after bleomycin treatment, PN−/− mice showed resistance to these changes. In vitro, dermal fibroblasts from PN−/− mice showed reduced transcript expression of alpha smooth actin and procollagen type-I alpha 1 (Col1α1) induced by transforming growth factor beta 1 (TGFβ1). Furthermore, recombinant mouse periostin directly induced Col1α1 expression in vitro, and this effect was inhibited by blocking the αv integrin-mediated PI3K/Akt signaling either with anti-αv functional blocking antibody or with the PI3K/Akt kinase inhibitor LY294002. Conclusion Periostin plays an essential role in the pathogenesis of Bleomycin-induced scleroderma in mice. Periostin may represent a potential therapeutic target for human scleroderma.

Artemin causes hypersensitivity to warm sensation, mimicking warmth-provoked pruritus in atopic dermatitis.

BACKGROUNDnItch impairs the quality of life for many patients with dermatoses, especially atopic dermatitis (AD), and is frequently induced by a warm environment.nnnOBJECTIVEnTo determine the mechanism underlying itch induction by warmth, we focused on artemin, a member of glial cell line-derived neurotrophic factors (GDNFs).nnnMETHODSnA gene array assay revealed that artemin was expressed in substance P-treated dermal fibroblasts. The expression of artemin in healthy and AD-lesional skin was evaluated with immunohistochemistry and in situ hybridization. The impact of fibroblast-derived artemin on the proliferation and morphology of neural cell was investigated inxa0vitro. To confirm the involvement of artemin in skin sensibility, wild-type and GDNF family receptor α3 knockout mice were employed for sensory examination.nnnRESULTSnArtemin-expressing fibroblasts accumulated in skin lesions of patients with AD. Artemin induced cell proliferation of a neuroblastoma cell line inxa0vitro, and intradermal injection of artemin in mice resulted in peripheral nerve sprouting and thermal hyperalgesia. Artemin-treated mice demonstrated scratching behavior in a warm environment, but mice deficient for GDNF family receptor α3, a potent artemin receptor, did not show this behavior. Furthermore, the escaping response to heat stimulus was attenuated in GDNF family receptor α3 knockout mice, suggesting that artemin may contribute to sensitivity to heat.nnnCONCLUSIONnThese data suggest that dermal fibroblasts secrete artemin in response to substance P, leading to abnormal peripheral innvervation and thermal hyperalgesia. We hypothesize that artemin lowers the threshold of temperature-dependent itch sensation and might therefore be a novel therapeutic target for treating pruritic skin disorders, including AD.