Atopic dermatitis

Anti-immunoglobulin E in the treatment of refractory atopic dermatitis

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease affecting > 10% of children and 1-3% of adults, and can cause significant morbidity. The incidence of AD seems to be increasing. Omalizumab, a monoclonal antibody, has recently been suggested as a potential new systemic treatment for patients with recalcitrant AD with elevated IgE levels, based on its efficacy in treating asthma and allergic rhinitis. We report a study of 10 patients with AD (aged 19-35 years) who received anti-IgE treatment for persistent asthma. All patients, regardless of IgE value, were treated with a fixed schedule of eight cycles of omalizumab 300 mg administered subcutaneously at intervals of 2 weeks. Eczema symptoms were scored at baseline and after 2, 4 and 6 months of treatment. There was a steady improvement in the objective SCORAD (SCORing Atopic Dermatitis), with significantly lower scores observed at the 6-month evaluation. At 2 months after the end of treatment, two patients had a very good result (SCORAD reduction of > 50%), five patients had a satisfactory result (reduction of 25-50%), and three patients had no clinically relevant result (reduction of 25-50%). No patient had worsening of the AD (increase of > 25% in SCORAD), and once a clinical improvement occurred, none of the patients experienced worsening of their eczema symptoms while on omalizumab. With the caveats of the financial expense and unknown long-term risks of malignancy associated with omalizumab, this drug should be considered for treatment-resistant patients with AD, particularly patients with high IgE level whose symptoms are not controlled by routine therapies. Omalizumab has proven useful in treating asthma, but it may also prove valuable for other conditions, such as allergic rhinitis, food allergies, chronic urticaria, and AD, as shown by the present study.

Modern methods and approaches to studying the role of neurotransmitters in the pathogenesis of chronic inflammatory skin diseases accompanied with itching

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Management of patients with atopic dermatitis: the role of emollient therapy

Atopic dermatitis is a common inflammatory skin disorder that afflicts a growing number of young children. Genetic, immune, and environmental factors interact in a complex fashion to contribute to disease expression. The compromised stratum corneum found in atopic dermatitis leads to skin barrier dysfunction, which results in aggravation of symptoms by aeroallergens, microbes, and other insults. Infants—whose immune system and epidermal barrier are still developing—display a higher frequency of atopic dermatitis. Management of patients with atopic dermatitis includes maintaining optimal skin care, avoiding allergic triggers, and routinely using emollients to maintain a hydrated stratum corneum and to improve barrier function. Flares of atopic dermatitis are often managed with courses of topical corticosteroids or calcineurin inhibitors. This paper discusses the role of emollients in the management of atopic dermatitis, with particular emphasis on infants and young children.

Atopic dermatitis results in intrinsic barrier and immune abnormalities: implications for contact dermatitis

Atopic dermatitis (AD), as well as irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD), are common skin diseases. These diseases are characterized by skin inflammation mediated by activated innate immunity or acquired immune mechanisms. Although AD, ICD, and ACD can be encountered in pure forms by allergists and dermatologists, patients with AD often present with increased frequency of ICD and ACD. Although a disturbed barrier alone could potentiate immune reactivity in patients with AD through increased antigen penetration, additional immune mechanisms might explain the increased susceptibility of atopic patients to ICD and ACD. This review discusses cellular pathways associated with increased skin inflammation in all 3 conditions and presents mechanisms that might contribute to the increased rate of ICD and ACD in patients with AD.

Effects of schizandrin on the expression of thymic stromal lymphopoietin in human mast cell line HMC-1

AIMS

Thymic stromal lymphopoietin (TSLP) plays an important role in allergic diseases such as asthma and atopic dermatitis. Schizandrin has various effects such as anti-asthmatic, anti-cancer and anti-inflammatory effects. However, the effect of schizandrin on the production of TSLP has not been clarified. Thus, we investigated how schizandrin inhibits the production of TSLP in the human mast cell line HMC-1 cells.

MAIN METHODS

We used enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, luciferase assay, and Western blot analysis to investigate the effects of schizandrin.

KEY FINDINGS

Schizandrin inhibited the production and mRNA expression of TSLP in HMC-1 cells. The maximal inhibition rate of TSLP production by schizandrin (10 μM) was 68.62 ± 3.47%. Schizandrin inhibited the translocation and luciferase activity of nuclear factor-κB induced by phorbol myristate acetate plus A23187. In the activated HMC-1 cells, the activation of caspase-1 was increased, whereas the activation of caspase-1 was decreased by pretreatment with schizandrin.

SIGNIFICANCE

These results suggest that schizandrin can be used to treat inflammatory and atopic diseases through the inhibition of TSLP.

Long term treatment concepts and proactive therapy for atopic eczema

Atopic eczema, also known as atopic dermatitis, is a frequent, highly pruritic, chronic skin disease, which is typically running in flares. The traditional treatment mainly consists of the reactive application of topical anti-inflammatory agents such as topical corticosteroids and topical calcineurin inhibitors. The short term benefit of this approach is well known, but long term remission between flares is difficult to achieve. Therefore, innovative long-term treatment strategies targeting flare prevention and skin barrier stabilization are needed. We and others have shown that normal looking, non-lesional skin of atopic dermatitis patients is immunobiologially not normal but characterized by an invisible inflammation and barrier defect. This has led to the novel concept of proactive therapy, which is defined as long-term, low-dose intermittent application of anti-inflammatory therapy to the previously affected skin, together with an ongoing emollient treatment of unaffected skin. This review article describes the most important long-term treatment options for atopic dermatitis, which includes emollient therapy, the novel concept of proactive treatment, the different ultraviolet light modalities and a selection of systemic immunosuppressive drugs and biologics. Current trial data, licensed indications, off-label use and relevant side effects of the different treatment modalities are summarized.

[Atopic dermatitis]

Atopic dermatitis (AD), or atopic eczema, is a pruriginous inflammatory dermatosis with a genetic predisposition evolving in recurrent flare-ups on a background of chronicity, affecting essentially infants and small children. The clinical phenotype of AD results from interactions between genes and susceptibility, a defect in the cutaneous barrier function (abnormalities in filaggrin and the proteins of the epidermic differentiation complex) and dysfunction of the innate and/or adaptive immune response. With its multifactorial origin, it is dependent on the TH2 lymphocyte system, with a tendency to produce immunoglobulin E (IgE) and the risk of asthma, rhinitis, or allergic conjunctivitis define an atopic susceptibility. Staphylococcus aureus colonization plays a vital role in the perpetuation of the inflammatory phenomena. The disease often regresses in older children. Its prevalence is on the rise in industrialized countries. Diagnosis is clinical, facilitated by certain criteria initially proposed by Hanifin and Rajka and then simplified by Williams. The allergological investigation is reserved for cases that are stubborn, severe, or associated with respiratory symptoms. AD is a dermatosis that evolves in erratic and often unpredictable flare-ups. AD flare-up treatment is based on local corticosteroid therapy. Maintenance therapy attempts to correct the cutaneous dryness with hydrating products whose efficacy has now been proven. Optimal management includes the family's and/or the child's comprehension of the treatment, explaining to them that the goal to reach is not only to relieve the child, but also to attempt to modify the course of the disease. AD is thus a star disease and a public health problem. The major progress made in the comprehension of the physiopathological mechanisms of AD promise targeted therapies from new biotechnologies.

Increased plasma LIGHT levels in patients with atopic dermatitis

LIGHT [the name of which is derived from 'homologous to lymphotoxins, exhibits inducible expression, competes with herpes simplex virus glycoprotein D for herpes simplex virus entry mediator (HVEM), and expressed by T lymphocytes'], is a member of the tumour necrosis factor superfamily that is involved in various inflammatory diseases. We aimed to estimate the relevance of plasma LIGHT levels as a biomarker for atopic dermatitis (AD). In order to understand the putative role of LIGHT in AD pathogenesis, we also investigate the effects of LIGHT on a monocytic cell line, human acute monocytic leukaemia cell line (THP-1). We examined plasma LIGHT levels, total serum IgE, serum value of CCL17 and peripheral blood eosinophil counts in patients with AD and healthy subjects. The effects of LIGHT on activation and apoptosis in THP-1 cells were also investigated. The plasma concentrations of LIGHT in AD patients were significantly higher than those in healthy individuals and the concentrations decreased as the symptoms were improved by treatment. The LIGHT plasma concentrations correlated with IgE levels and the Severity Scoring of AD (SCORAD) index. In addition, LIGHT stimulation increased expression of CD86 and induced production of interleukin-1β in THP-1 cells. Apoptosis was inhibited, the Bcl-2 level increased and the caspase-3 level decreased in THP-1 cells stimulated with LIGHT, compared to unstimulated control cells. These results suggest that plasma LIGHT levels may be one of the promising biomarkers for AD.

Dissecting the causes of atopic dermatitis in children: less foods, more mites

Atopic dermatitis (AD) is a common, chronic or chronically relapsing, multifactorial skin disease that mainly occurs in children but affects also adults. AD usually begins early in life and often concerns people with a personal or family history of asthma and allergic rhinitis. AD is characterized by eczematous changes in the epidermis and originates from a late, T-cell mediated reaction associated to the formation and production of memory T-cell of TH2 type, occurrence of homing receptor at skin level and cutaneous lymphocyte-associated (CLA) antigens. Extrinsic or allergic AD, but not intrinsic AD, shows high total serum IgE levels and the presence of specific IgE for environmental and food allergens. A pivotal role in the pathogenesis of AD is played by filaggrin, a protein contained in the granular layer of the epidermis regulating the aggregation of keratin filaments. Mutation in the filaggrin gene causes decreased barrier function of the corny layers of the epidermis. This favours the enter through the skin of environmental allergens, especially the house dust mite, that further facilitates such entering by the proteolytic activity of its major allergen Der p 1. In fact, recent advances suggest that the dust mite, more than foods, is the major cause of allergic AD. As far as the causal diagnosis of AD is concerned, there is notable evidence supporting the capacity of the atopy patch test (APT) to reproduce the pathophysiologic events of AD. This makes APT a valuable diagnostic tool for AD.

Comparative effectiveness of topical calcineurin inhibitors in adult patients with atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by extreme pruritis and lichenified papules and plaques that may begin in or persist into adulthood. Topical corticosteroids are first-line prescription therapy for AD; they are efficacious and have a well established safety profile. The topical calcineurin inhibitors tacrolimus and pimecrolimus were approved by the US FDA in 2000 and 2001, respectively, as second-line topical therapy for AD. This review evaluates the available studies on the comparative effectiveness, safety, cost, and impact on quality of life of topical corticosteroids and topical calcineurin inhibitors for the treatment of adult AD. Tacrolimus was found to be as effective as class III-V topical corticosteroids for AD of the trunk and extremities, and more effective than low-potency class VI or VII corticosteroids for AD of the face or neck. Pimecrolimus was less effective than both tacrolimus and low-potency topical corticosteroids for moderate to severe AD. The short-term safety studies found that, compared with topical corticosteroid-treated adults, patients treated with topical calcineurin inhibitors had an increased frequency of application-site reactions, an equivalent infection risk, and a decreased risk of skin atrophy. The long-term safety of topical calcineurin inhibitors remains under investigation. Currently published studies that evaluated the comparative cost and quality-of-life effects compared tacrolimus with less potent topical corticosteroids despite the availability of equivalent potency corticosteroids. Further cost and quality-of-life studies are needed that compare topical calcineurin inhibitors with stronger classes of topical corticosteroids over longer time periods. The available clinical trials data do not suggest an efficacy advantage for topical calcineurin inhibitors over topical corticosteroids in adults with AD of the trunk and extremities, and there is not yet adequate evidence to support topical calcineurin inhibitors as first-line therapy for adult AD.

Mechanisms of IFN-γ-induced apoptosis of human skin keratinocytes in patients with atopic dermatitis

BACKGROUND

Enhanced apoptosis of keratinocytes is the main cause of eczema and spongiosis in patients with the common inflammatory skin disease atopic dermatitis (AD).

OBJECTIVE

The aim of the study was to investigate molecular mechanisms of AD-related apoptosis of keratinocytes.

METHODS

Primary keratinocytes isolated from patients with AD and healthy donors were used to study apoptosis by using annexin V/7-aminoactinomycin D staining. Illumina mRNA Expression BeadChips, quantitative RT-PCR, and immunofluorescence were used to study gene expression. In silico analysis of candidate genes was performed on genome-wide single nucleotide polymorphism data.

RESULTS

We demonstrate that keratinocytes of patients with AD exhibit increased IFN-γ-induced apoptosis compared with keratinocytes from healthy subjects. Further mRNA expression analyses revealed differential expression of apoptosis-related genes in AD keratinocytes and skin and the upregulation of immune system-related genes in skin biopsy specimens of chronic AD lesions. Three apoptosis-related genes (NOD2, DUSP1, and ADM) and 8 genes overexpressed in AD skin lesions (CCDC109B, CCL5, CCL8, IFI35, LYN, RAB31, IFITM1, and IFITM2) were induced by IFN-γ in primary keratinocytes. The protein expression of IFITM1, CCL5, and CCL8 was verified in AD skin. In line with the functional studies and AD-related mRNA expression changes, in silico analysis of genome-wide single nucleotide polymorphism data revealed evidence of an association between AD and genetic markers close to or within the IFITM cluster or RAB31, DUSP1, and ADM genes.

CONCLUSION

Our results demonstrate increased IFN-γ responses in skin of patients with AD and suggest involvement of multiple new apoptosis- and inflammation-related factors in the development of AD.

Does "autoreactivity" play a role in atopic dermatitis?

The role of autoimmunity in atopic dermatitis (AD) is unclear. We sought to critically examine the occurrence, correlation with severity, and possible causative role of autoreactivity in patients with AD. Our systematic review of studies identified from MEDLINE included 31 experiments that described autoreactivity in patients with AD. We defined autoreactivity as in vitro or in vivo evidence of immune response to autologous human, generic human, or recombinant human proteins or other tissue/cellular components. Autoreactivity prevalence in patients with AD ranged from 23% to 91% in 14 studies involving 2644 participants, although it did not appear to vary with age, sex, or disease duration. In contrast to studies of AD, IgE autoreactivity was not found in healthy subjects or in those with allergic rhinoconjunctivitis, psoriasis, systemic lupus erythematosus, or other inflammatory diseases (8 studies of 816 participants). Two reports found a positive correlation between autoreactivity and AD severity. We suggest that autoreactivity might be playing a causative role in AD based on the magnitude and specificity of the associations found; plausible mechanisms through IgE autoantibodies, IgG autoantibodies, and T(H)1 autoreactivity; and experimental elicitation of eczematous lesions after provocation. Whether autoantibodies contribute to AD chronicity now needs to be examined in longitudinal studies.

Interplay of filaggrin loss-of-function variants, allergic sensitization, and eczema in a longitudinal study covering infancy to 18 years of age

Background

Immune specific genes as well as genes regulating the formation of skin barrier are major determinants for eczema manifestation. There is a debate as to whether allergic sensitization and filaggrin gene (FLG) variants lead to eczema or FLG variants and eczema increase the risk of allergic sensitization. To investigate the time-order between eczema and allergic sensitization with respect to FLG variants, data from a large prospective study covering infancy to late adolescence were analyzed.

Methodology/Principal Findings

Repeated measurements of eczema and allergic sensitization (documented by skin prick tests) at ages 1, 2, 4, 10, and 18 years were ascertained in the Isle of Wight birth cohort (n = 1,456). Three transition periods were analyzed: age 1-or-2 to 4, 4 to 10, and 10 to 18 years. FLG variants were genotyped in 1,150 participants. Over the three transition periods, in temporal sequence analyses of initially eczema-free participants, the combined effect of FLG variants and allergic sensitization showed a 2.92-fold (95% CI: 1.47–5.77) increased risk ratio (RR) of eczema in subsequent examinations. This overall risk was more pronounced at a younger age (transition period 1-or-2 to 4, RR = 6.47, 95% CI: 1.96–21.33). In contrast, FLG variants in combination with eczema showed a weaker, but significant, risk ratio for subsequent allergic sensitization only up to 10 years of age.

Conclusions/Significance

Taking the time order into account, this prospective study demonstrates for the first time, that a combination of FLG variants and allergic sensitization increased the risk of eczema in subsequent years. Also FLG variants interacted with eczema and increased the risk of subsequent allergic sensitization, which, was limited to the younger age. Hence, early restoration of defective skin barrier could prevent allergic sensitization and subsequently reduce the risk of eczema development.

The lipid alterations in the stratum corneum of dogs with atopic dermatitis are alleviated by topical application of a sphingolipid-containing emulsion

BACKGROUND

Atopic dermatitis (AD) results from an altered skin barrier associated with defects in the lipid composition of the skin. Dogs with AD present similar clinical symptoms to humans, and may be a useful model for investigations into AD.

AIM

To analyse the changes occurring in the lipids of the stratum corneum (SC) of dogs with AE after 3 weeks of topical treatment with an emulsion containing ceramides, free fatty acids (FFAs) and cholesterol (skin lipid complex; SLC).

METHODS

Nonlesional SC was collected by tape stripping from control and treated areas. Free and protein-bound lipids were purified, and the various classes were isolated by column chromatography, analysed by thin-layer chromatography and assayed.

RESULTS

Ceramides, FFA and cholesterol were all found to be lower in the skin of untreated dogs with AD than in normal dogs, and the topical treatment resulted in significantly increased values for ceramides. Conversely, only trace amounts of glucosylceramides were present in normal SC, but a high concentration (27 μg per mg protein) was detected in canine atopic SC, which disappeared after treatment with SLC. There was a heterogeneous distribution of all of the lipids in the different layers of canine atopic SC, which was more pronounced for protein-bound than for free lipids. Following topical treatment, the protein-bound lipid content normalized.

CONCLUSIONS

Topical treatment with SLC resulted in a significant improvement of the lipid biosynthesis of keratinocytes in atopic dogs, thereby potentially enabling the formation of a tighter epidermal barrier.

Amorphous silica nanoparticles size-dependently aggravate atopic dermatitis-like skin lesions following an intradermal injection

Background

Due to the rising use of nanomaterials (NMs), there is concern that NMs induce undesirable biological effects because of their unique physicochemical properties. Recently, we reported that amorphous silica nanoparticles (nSPs), which are one of the most widely used NMs, can penetrate the skin barrier and induce various biological effects, including an immune-modulating effect. Thus, it should be clarified whether nSPs can be a risk factor for the aggravation of skin immune diseases. Thus, in this study, we investigated the relationship between the size of SPs and adjuvant activity using a model for atopic dermatitis.

Results

We investigated the effects of nSPs on the AD induced by intradermaly injected-mite antigen Dermatophagoides pteronyssinus (Dp) in NC/Nga mice. Ear thickness measurements and histopathological analysis revealed that a combined injection of amorphous silica particles (SPs) and Dp induced aggravation of AD in an SP size-dependent manner compared to that of Dp alone. In particular, aggravation was observed remarkably in nSP-injected groups. Furthermore, these effects were correlated with the excessive induction of total IgE and a stronger systemic Th2 response. We demonstrated that these results are associated with the induction of IL-18 and thymic stromal lymphopoietin (TSLP) in the skin lesions.

Conclusions

A particle size reduction in silica particles enhanced IL-18 and TSLP production, which leads to systemic Th2 response and aggravation of AD-like skin lesions as induced by Dp antigen treatment. We believe that appropriate regulation of nanoparticle physicochemical properties, including sizes, is a critical determinant for the design of safer forms of NMs.

IL-33 and ST2 in atopic dermatitis: expression profiles and modulation by triggering factors

In the acute phase of atopic dermatitis (AD), T-helper type 2 (Th2) cytokines characterize the inflammatory response in the skin. IL-33 is a new tissue-derived cytokine, which is mainly expressed by cells of barrier tissues, and is known to activate Th2 lymphocytes, mast cells, and eosinophils. IL-33 signals through a receptor complex consisting of IL-33-specific receptor ST2 and a co-receptor IL-1RAcP. As IL-33 is known to promote Th2-type immunity, we examined expression profiles of IL-33 and its receptor components in human AD skin, in the murine model of AD, and in various cell models. We found increased expression of IL-33 and ST2 in AD skin after allergen or staphylococcal enterotoxin B (SEB) exposure, as well as in the skin of 22-week-old filaggrin-deficient mice. In addition, skin fibroblasts, HaCaT keratinocytes, primary macrophages, and HUVEC endothelial cells efficiently produced IL-33 in response to the combined stimulation of tumor necrosis factor-α and IFN-γ, which was further enhanced by a mimetic of double-stranded RNA. Finally, the increased expression of IL-33 and ST2 caused by irritant, allergen, or SEB challenge was suppressed by topical tacrolimus treatment. These results suggest an important role for IL-33-ST2 interaction in AD and highlight the fact that bacterial and viral infections may increase the production of IL-33.

Emerging applications of nanomedicine in dermatology

BACKGROUND

Nanotechnology is a new branch of engineering consisting of the usage of nanoscale particles (100 nm and smaller). Nanomedicine is the application of nanoscale technologies for diagnostic and therapeutic purposes in medicine. Nanodermatology, nanotechnology applied to dermatology, represents one of the most advanced field for which an increasing interest, both economic and scientific, is rising. The skin is the first point of contact for a whole host of nanomaterials, ranging from topical preparations, articles of clothing and household products, to sporting goods and industrial manufactured goods. Applications of nanomedicine in dermatology include new direction in medical diagnosis, monitoring and treatment. Gold nanoparticle, quantum dots and magnetic nanoparticles are used in non-invasive nanoimaging of high-resolution dermoscopy, microscopy, nanopunch, and spectroscopy, offering advanced diagnostic and therapeutic modalities. Nanotherapeutics has been considered in immunotherapy, genetherapy, and drug therapy. In drug therapy, because of size reduction or encapsulation of drug particles, the therapeutic potential of water insoluble and unstable drugs improve, and also facilitate the delivery of small molecules across blood, skin, nails, and pilosebaceous unit.

AIMS

To review therapeutic applications and benefits of nanomedicine in esthetic dermatology, treatment of malignancies, and inflammatory skin diseases.

Cell-penetrating peptides as antifungals towards Malassezia sympodialis

AIM

To determine whether different antimicrobial peptides (AMPs) and cell-penetrating peptides (CPPs) are able to inhibit the growth of the commensal yeast Malassezia sympodialis, which can act as a trigger factor in different skin disorders, such as atopic eczema (AE), seborrhoeic eczema (SE) and dandruff.

METHODS AND RESULTS

The antifungal activity of 21 different AMPs and CPPs was investigated by microdilution assay and plate counting to determine the number of colony forming units. Five CPPs and one AMP showed fungicidal activity at submicromolar concentrations. Importantly, no membrane damage on human keratinocytes was detected after peptide treatment.

CONCLUSIONS

Several CPPs, while being nontoxic to mammalian cells, possess growth inhibitory activity on the very stringent yeast M. sympodialis.

SIGNIFICANCE AND IMPACT OF STUDY

Our findings that five CPPs and one AMP that are harmless towards mammalian cells act as antifungal agents against M. sympodialis opens up the possibility to use these in the treatment for AE, SE and dandruff. To our knowledge, this is the first time peptides have been identified as antifungal agents against M. sympodialis. Further studies to elucidate the mechanism are warranted.

The suppression of thymic stromal lymphopoietin expression by selenium

Thymic stromal lymphopoietin (TSLP) is a key mediator of allergic diseases such as allergic rhinitis, asthma, and atopic dermatitis. Selenium (Se) has various effects such as antioxidant, antitumor, antiulcer, and anti-inflammatory effects. However, the effect of Se on the production of TSLP has not been clarified. Thus, we investigated how Se inhibits the production of TSLP in the human mast cell line, HMC-1 cells. Se suppressed the production and mRNA expression of TSLP in HMC-1 cells. The maximal inhibition rate of TSLP production by Se (10 μM) was 59.14 ± 1.10%. In addition, Se suppressed the nuclear factor-κB luciferase activity induced by phorbol myristate acetate plus A23187. In the activated HMC-1 cells, the activation of caspase-1 was increased; whereas the activation of caspase-1 was decreased by pretreatment with Se. These results suggest that Se can be used to treat inflammatory and atopic diseases through the suppression of TSLP.

Signaling by IL-31 and functional consequences

Cytokines are key to control cellular communication. Interleukin-31 (IL-31) was recently discovered as a new member of the IL-6 family of cytokines. IL-31 signals through a heterodimeric receptor composed of OSMR and IL-31RA, a complex that stimulates the JAK-STAT, the RAS/ERK and the PI3K/AKT signal transduction pathways. The available data suggests that IL-31 is important for both innate and adaptive immunity in tissues that are in close contact with the environment, i.e. the skin, the airways and the lung, and the lining of the intestine. Enhanced expression of IL-31 is associated with a number of diseases, including pruritic diseases such as atopic dermatitis, but also in allergy and inflammatory bowel disease. In these tissues IL-31 coordinates the interaction of different immune cells, including T-cells, mast cells, and eosinophils, with epithelial cells. In this review we have summarized the available data on IL-31 and its receptor, their expression pattern and how they are regulated. We describe the current state of knowledge of the involvement of IL-31 in diseases, both in humans and in mouse models. From these studies it is becoming clear that IL-31 plays an important role in the proper functioning of the skin and of airway and intestinal epithelia. The findings available suggest that IL-31 might be an interesting target for directed drug therapy.

Epidermal barrier in atopic dermatitis

Atopic dermatitis (AD) is a complex disease that affects up to 20% of children and impacts the quality of patients and families in a significant manner. New insights into the pathophysiology of AD point to an important role of structural abnormalities in the epidermis combined with immune dysregulation. Filaggrin (FLG) is synthesized as a large precursor, profilaggrin, and is expressed in the upper layers of the epidermis. FLG plays a critical role in the epidermal barrier, and FLG mutations cause abnormal epidermal function. FLG mutations are strongly associated with early-onset, and persistent severe AD. In addition, FLG deficiency in the epidermis is related to allergic sensitization and asthma. The basic skin care including repair and protection of the skin barrier with proper hydration and topical anti-inflammatory therapy is important to control the severity of skin disease in patients with AD.

Th2 Cytokines and Atopic Dermatitis

Atopic dermatitis (AD), a chronic relapsing inflammatory skin disease, is increasing in prevalence around the world. Intensive research is ongoing to understand the mechanisms involved in the development of AD and offer new treatment options for patients suffering from AD. In this review, we highlight the importance of allergic Th2 responses in the development of the disease and summarize relevant literature, including genetic studies, studies of human skin and mechanistic studies on keratinocytes and mouse models of AD. We discuss the importance of the skin barrier and review recent findings on the pro-Th2 cytokines TSLP, IL-25, and IL-33, notably their ability to polarize dendritic cells and promote Th2 responses. After a brief update on the contribution of different T-cell subsets to AD, we focus on Th2 cells and the respective contributions of each of the Th2 cytokines (IL-4, IL-13, IL-5, IL-31, and IL-10) to AD. We conclude with a brief discussion of the current gaps in our knowledge and technical limitations.

Clinical features of the extrinsic and intrinsic types of adult-onset atopic dermatitis

Background

Most study concerning the prevalence and dermatological manifestations of the extrinsic and the intrinsic form of atopic dermatitis (AD) were performed in children and adult AD related to the early-onset AD extending to adult life. Adult-onset AD is a subgroup of AD. Apart from the typical eczematous flexural distribution pattern of AD, this group may also have nontypical morphology and localization.

Objective

The purpose of this study was to compare the clinical and diagnostic features of Thai patients with extrinsic and intrinsic type of adult-onset AD.

Methods

We retrospectively studied case records of patients diagnosed as adult-onset AD at the skin allergy clinic, Department of Dermatology, Siriraj Hospital, Mahidol University, Bangkok, Thailand from June, 2006 to May, 2008. The diagnosis of AD was made according to the criteria of Hanifin and Rajka and the severity of AD in each patient were assessed using the eczema area and severity index and the Rajka and Langeland score.

Results

Fifty six patients were enrolled. Eighty-seven percent of patients were extrinsic AD (eAD). Females predominated in both groups. Patients with eAD more commonly had typical lichenified/exudative eczematous lesions, especially on the antecubital and popliteal areas, when compared with patients with intrinsic AD (iAD). Nummular and follicular lesions were more commonly seen in iAD group than the eAD group. The most common area of involvement in the iAD was non-flexural area, followed by flexural area and extensor area. The severity of both iAD and eAD did not show a significant difference.

Conclusion

The eAD type of adult-onset AD was more common than the iAD type. Patients with eAD frequently had flexural lichenification whereas the iAD group tended to have nonflexural area involvement. The severity of both iAD and eAD did not show a significant difference.

Altered peripheral invariant natural killer T cells in atopic dermatitis

BACKGROUND

Conflicting data exist on the number of invariant NKT (iNKT) cells in atopic dermatitis (AD); furthermore, no data have been published on their functional capacity.

METHODS

The frequency and number of circulating CD3+6B11+ iNKT cells and their CD4+ and CD4- subpopulations were evaluated in peripheral blood obtained from 41 patients with AD by four-color flow cytometry. Likewise, functional properties of iNKT cells were measured by five-color intracellular cytokine staining.

RESULTS

The number and percentage of total iNKT cells and their CD4/CD8 subpopulations were significantly lower than the controls. Of further importance, the CD4-CD8- (double negative, DN) iNKT subgroup showed the strongest positive correlation with total iNKT cells. In addition, the DN subgroup exhibited the most pronounced functional alteration with significantly decreased levels of intracellular IFNγ and significantly increased levels of intracellular IL-4 in AD patients compared with the controls.

CONCLUSION

The significantly altered number and cytokine production of iNKT cells from AD patients suggests that these cells may play an important role in the pathogenesis of AD.

Cancer risk in patients with allergic rhinitis, asthma and atopic dermatitis: a nationwide cohort study in Taiwan

It has long been a debate that whether atopy is a risk factor or protective factor for cancer. However, no large-scale study of different cancers in patients with atopic diseases has been conducted among Asians. Here, we conducted a nationwide study to evaluate the cancer risk in patients with allergic rhinitis (AR), asthma and atopic dermatitis (AD). Drawing on Taiwan's National Health Insurance Research Database, 225,315 patients with AR, 107,601 patients with asthma and 34,263 patients with AD without prior cancers were identified in the period from 1996 to 2008. The standard incidence ratio (SIR) of each cancer was calculated. Although the overall cancer risks in patients with atopic symptoms were not increased, the risks were slightly elevated in female patients with AR or asthma (SIR: 1.13 and 1.08, AR and asthma, respectively) and slightly decreased in males patients with AR. Those aged 20-39 years-old possessed the highest risk. A higher risk of developing brain cancer was found in patients with atopic diseases, and patient with AR or asthma also had an elevated risk of developing cancer of kidney and urinary bladder. In contrast, the risk of nonmelanoma skin cancer was lower in patients with AR and asthma. Compared to patients with only one atopic disease, those with more than one atopic disease had lower cancer risks. Our data suggests that the association between atopy and cancer is site-specific.

Skin barrier homeostasis in atopic dermatitis: feedback regulation of kallikrein activity

Atopic dermatitis (AD) is a widely spread cutaneous chronic disease characterised by sensitive reactions (eg. eczema) to normally innocuous elements. Although relatively little is understood about its underlying mechanisms due to its complexity, skin barrier dysfunction has been recognised as a key factor in the development of AD. Skin barrier homeostasis requires tight control of the activity of proteases, called kallikreins (KLKs), whose activity is regulated by a complex network of protein interactions that remains poorly understood despite its pathological importance. Characteristic symptoms of AD include the outbreak of inflammation triggered by external (eg. mechanical and chemical) stimulus and the persistence and aggravation of inflammation even if the initial stimulus disappears. These characteristic symptoms, together with some experimental data, suggest the presence of positive feedback regulation for KLK activity by inflammatory signals. We developed simple mathematical models for the KLK activation system to study the effects of feedback loops and carried out bifurcation analysis to investigate the model behaviours corresponding to inflammation caused by external stimulus. The model analysis confirmed that the hypothesised core model mechanisms capture the essence of inflammation outbreak by a defective skin barrier. Our models predicted the outbreaks of inflammation at weaker stimulus and its longer persistence in AD patients compared to healthy control. We also proposed a novel quantitative indicator for inflammation level by applying principal component analysis to microarray data. The model analysis reproduced qualitative AD characteristics revealed by this indicator. Our results strongly implicate the presence and importance of feedback mechanisms in KLK activity regulation. We further proposed future experiments that may provide informative data to enhance the system-level understanding on the regulatory mechanisms of skin barrier in AD and healthy individuals.

Repressor of GATA negatively regulates murine contact hypersensitivity through the inhibition of type-2 allergic responses

Repressor of GATA (ROG) inhibits Th2 cell differentiation and allergic airway inflammation in the lung. To determine the role of ROG in the pathogenesis of contact hypersensitivity (CHS), a hapten-induced mouse model of CHS using ROG Tg and ROG-deficient (ROG(-/-)) was used. ROG Tg mice showed little ear swelling, while ROG(-/-) mice showed enhanced ear swelling in comparison to wild type mice. Interstitial edema and mast cell degranulation at the local inflammation sites were mild in ROG Tg mice and exacerbated in ROG(-/-) mice. In addition, the serum total IgE and hapten-specific IgG1 levels were increased in ROG(-/-) mice. Adoptive transfer of ROG(-/-) CD4(+) T cells exacerbated CHS in wild type mice, while transfer of ROG Tg CD4(+) T cells resulted in the attenuation of CHS. These results indicate ROG negatively regulates the induction of CHS by controlling the CD4(+) T cell-mediated allergic responses, including IgE generation and mast cell degranulation.

Contrasting pathogenesis of atopic dermatitis and psoriasis--part I: clinical and pathologic concepts

Atopic dermatitis and psoriasis are 2 of the most common inflammatory skin diseases. They are similar in that they are complex inherited diseases involving genes that encode immune components and structural proteins that regulate differentiation of epidermal cells. Each disease is characterized by proliferation of epidermal keratinocytes and abnormal cornification or terminal differentiation in the epidermis; skin lesions contain immune infiltrates of T cells, dendritic cells, and other types of leukocytes. We review similarities between the diseases and differences in epidermal barrier defects and immune cells. We also propose mechanisms of pathogenesis based on differences in the balance of immune cell subsets that could cause the phenotypes that distinguish these diseases. The first part of this 2-part review focuses on the clinical and pathologic features of the diseases; the second part discusses differences in immune cell subsets between atopic dermatitis and psoriasis and recent therapeutic strategies.

Children and adolescents' health-related quality of life in relation to eczema, asthma and hay fever: results from a population-based cross-sectional study

PURPOSE

Several studies have looked at the relationship between childhood atopic disease and health-related quality of life (HRQoL), but existing research is limited by selected populations, small samples or lack to consider each of the three atopic conditions simultaneously.

METHODS

Impact of 4-week and 12-month occurrences of the three conditions on HRQoL were analysed by the use of complex sample general linear models alone and adjusted for the other atopic conditions, sociodemographics and mental health in a population-based sample (n = 6,518) of children and adolescents aged 11-17.

RESULTS

In univariate analyses, total HRQoL was significantly impacted by eczema and hay fever but not asthma with stronger effects for 4-week occurrence. In multivariate analyses, 12-month occurrence of hay fever and 4-week occurrence of eczema and hay fever significantly impacted on total HRQoL. Although most of the variance in HRQoL was explained by mental health, independent effects of the atopic conditions remained.

CONCLUSION

Atopic conditions impact HRQoL over and above mental health. When analysing the relationship between atopic conditions and HRQoL, it is important to consider more immediate versus less immediate effects of the conditions. Extent of impairment and the domains affected appear to vary when different time intervals are used.