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Staphylococcus aureus colonizes patients with atopic dermatitis (AD) and exacerbates disease by promoting inflammation. The present study investigated the safety and mechanisms of action of Staphylococcus hominis A9 (ShA9), a bacterium isolated from healthy human skin, as a topical therapy for AD. ShA9 killed S. aureus on the skin of mice and inhibited expression of a toxin from S. aureus (psm[alpha]) that promotes inflammation. A first-in-human, phase 1, double-blinded, randomized 1-week trial of topical ShA9 or vehicle on the forearm skin of 54 adults with S. aureus-positive AD (NCT03151148) met its primary endpoint of safety, and participants receiving ShA9 had fewer adverse events associated with AD. Eczema severity was not significantly different when evaluated in all participants treated with ShA9 but a significant decrease in S. aureus and increased ShA9 DNA were seen and met secondary endpoints. Some S. aureus strains on participants were not directly killed by ShA9, but expression of mRNA for psm[alpha] was inhibited in all strains. Improvement in local eczema severity was suggested by post-hoc analysis of participants with S. aureus directly killed by ShA9. These observations demonstrate the safety and potential benefits of bacteriotherapy for AD. First-in-human test of topical application of a commensal bacterium on skin of individuals with atopic dermatitis reduces colonization by proinflammatory Staphylococcus aureus., Author(s): Teruaki Nakatsuji [sup.1] , Tissa R. Hata [sup.1] , Yun Tong [sup.1] , Joyce Y. Cheng [sup.1] , Faiza Shafiq [sup.1] , Anna M. Butcher [sup.1] , Secilia S. [...]

Allergic diseases have in common a dysfunctional epithelial barrier, which allows the penetration of allergens and microbes, leading to the release of type 2 cytokines that drive allergic inflammation. The accessibility of skin, compared with lung or gastrointestinal tissue, has facilitated detailed investigations into mechanisms underlying epithelial barrier dysfunction in atopic dermatitis (AD). This Review describes the formation of the skin barrier and analyzes the link between altered skin barrier formation and the pathogenesis of AD. The keratinocyte differentiation process is under tight regulation. During epidermal differentiation, keratinocytes sequentially switch gene expression programs, resulting in terminal differentiation and the formation of a mature stratum corneum, which is essential for the skin to prevent allergen or microbial invasion. Abnormalities in keratinocyte differentiation in AD skin result in hyperproliferation of the basal layer of epidermis, inhibition of markers of terminal differentiation, and barrier lipid abnormalities, compromising skin barrier and antimicrobial function. There is also compelling evidence for epithelial dysregulation in asthma, food allergy, eosinophilic esophagitis, and allergic rhinosinusitis. This Review examines current epithelial barrier repair strategies as an approach for allergy prevention or intervention., Allergic diseases such as atopic dermatitis (AD), food allergy (FA), asthma, and allergic rhinitis affect more than 30% of the population (1-3). These diseases have in common a dysfunctional epithelial [...]

Eczema vaccinatum (EV) is a complication of smallpox vaccination occurring in patients with atopic dermatitis. In affected individuals, vaccinia virus (VV) spreads through the skin, resulting in large primary lesions and satellite lesions, and infects internal organs. BALB/c mice inoculated with VV at sites of Th2-biased allergic skin inflammation elicited by epicutaneous ovalbumin (OVA) sensitization exhibited larger primary lesions that were erosive, more satellite lesions, and higher viral loads in skin and internal organs than mice inoculated in saline-exposed skin, unsensitized skin, or skin sites with Th1-dominant inflammation. VV inoculation in OVA-sensitized skin induced marked local expression of IL-17 transcripts and massive neutrophil infiltration compared to VV inoculation in saline-exposed skin. Treatment with anti-IL-17 decreased the size of primary lesions, numbers of satellite lesions, and viral loads. Addition of IL-17 promoted VV replication in skin explants. These results suggest that IL-17 may be a potential therapeutic target in EV. atopic dermatitis | eczema vaccinatum

OBJECTIVE. Early exposure to solid foods in infancy has been associated with the development of allergy. The aim of this study was to examine the association between cereal-grain exposures (wheat, barley, rye, oats) in the infant diet and development of wheat allergy. METHODS. A total of 1612 children were enrolled at birth and followed to the mean age of 4.7 years. Questionnaire data and dietary exposures were obtained at 3, 6, 9, 15, and 24 months and annually thereafter. The main outcome measure was parent report of wheat allergy. Children with celiac disease autoimmunity detected by tissue transglutaminase autoantibodies were excluded. Wheat-specific immunoglobulin E levels on children reported to have wheat allergy were obtained. RESULTS. Sixteen children (1%) reported wheat allergy. Children who were first exposed to cereals after 6 months of age had an increased risk of wheat allergy compared with children first exposed to cereals before 6 months of age (after controlling for confounders including a family history of allergic disorders and history of food allergy before 6 months of age). All 4 children with detectable wheat-specific immunoglobulin E were first exposed to cereal grains after 6 months. A first-degree relative with asthma, eczema, or hives was also independently associated with an increased risk of wheat-allergy development. CONCLUSIONS. Delaying initial exposure to cereal grains until after 6 months may increase the risk of developing wheat allergy. These results do not support delaying introduction of cereal grains for the protection of food allergy. Key Words food allergy, wheat, solid-food exposure and introduction (timing), infant diet Abbreviations AAP--American Academy of Pediatrics DAISY--Diabetes Autoimmunity Study in the Young IgE--immunoglobulin E OR--odds ratio CI--confidence interval, FLOOD ALLERGIES REPRESENT a significant problem that affects 6% of infants younger than 3 years. (1) The development of food allergy results from the interaction between exposure of a genetically [...]

A monoclonal antibody called TNX-901 may reduce the risk of peanut allergy in susceptible people who are accidentally exposed to peanuts in other products, according to a study of 84 people with a peanut allergy. The antibody decreased their sensitivity to peanuts so they could tolerate up to nine peanuts. Most could only tolerate one peanut or less before taking the antibody.

Objectives. To review epidemiologic correlations between asthma and atopic dermatitis (AD), identify common features in disease pathophysiology, and review steps involved in the development of asthma therapy guidelines to assess the appropriateness of a similar process and approach for AD. Methods. A 7-member panel representing specialists in dermatology, allergy, asthma, immunology, and pediatrics from around the United States convened to review the current literature and evolving data on AD. Participants presented reviews to the panel on the epidemiology of asthma and AD, the genetic predisposition to allergic disease, the current understanding of the immunopathophysiology of AD, interrelationships between the pathologic pathways of asthma and AD, evolving treatment concepts and options in AD, and the applicability of the asthma treatment model and how it may be adapted for guideline development for AD. Commentary and criticism were recorded for use in document preparation. Results. There are clear epidemiologic parallels in asthma and AD. Importantly, AD frequently is the first manifestation of an atopic diathesis, which occurs in genetically predisposed individuals and also includes asthma and allergic rhinitis. Up to 80% of children with AD will eventually develop allergic rhinitis or asthma later in childhood. This classic "atopic triad" has numerous pathophysiologic elements in common, including cyclic nucleotide regulatory abnormalities, immune cell alterations, and inflammatory mediators and allergic triggers. New therapeutic options that target underlying immune mechanisms are available, and their place among treatments for AD is becoming established. Guidelines of care have been developed for asthma. The panel noted that the National Institutes of Health/National Heart, Lung, and Blood Institute guidelines for diagnosis and management of asthma, first issued in 1991, had a tremendous positive impact on many aspects of asthma treatment. It not only created a heightened awareness that asthma is a disease of chronic inflammation, but it also provided unified approaches for therapy and opened new areas of basic science and clinical research. In addition, the guidelines spurred interactions among physicians of various specialties and stimulated a great quantity of research in asthma therapy. It is anticipated that AD therapy guidelines would have similar positive outcomes. Conclusions. The panel concluded that, on the basis of current information and evolving therapeutic options, a clear rationale exists to support AD guideline development. The many parallels between AD and asthma suggest that processes and approaches used for the asthma therapy guidelines would be appropriate for AD. Pediatrics 2003;111:608-616; allergy, asthma, atopic dermatitis, treatment guidelines., ABBREVIATIONS. AD, atopic dermatitis; IgE, immunoglobulin E; NHLBI, National Heart, Lung, and Blood Institute. Epidemiologic studies conducted during the past 2 to 3 decades indicate that the prevalence of atopic [...]

The skin of people with atopic dermatitis appears to produce smaller than normal amounts of proteins that have antibiotic properties. This would explain why people with atopic dermatitis have an increased risk of skin infections. Atopic dermatitis is a chronic inflammation of the skin.

Genome sequences are available for many bacterial strains, but there has been little progress in using these data to understand the molecular basis of pathogen emergence and differences in strain virulence. Serotype M3 strains of group A Streptococcus (GAS) are a common cause of severe invasive infections with unusually high rates of morbidity and mortality. To gain insight into the molecular basis of this high-virulence phenotype, we sequenced the genome of strain MGAS315, an organism isolated from a patient with streptococcal toxic shock syndrome. The genome is composed of 1,900,521 bp, and it shares [approximately equal to] 1.7 Mb of related genetic material with genomes of serotype M1 and M18 strains. Phage-like elements account for the great majority of variation in gene content relative to the sequenced M1 and M18 strains. Recombination produces chimeric phages and strains with previously uncharacterized arrays of virulence factor genes. Strain MGAS315 has phage genes that encode proteins likely to contribute to pathogenesis, such as streptococcal pyrogenic exotoxin A (SpeA) and SpeK, streptococcal superantigen (SSA), and a previously uncharacterized phospholipase [A.sub.2] (designated Sla). Infected humans had anti-SpeK, -SSA, and -Sla antibodies, indicating that these GAS proteins are made in vivo. SpeK and SSA were pyrogenic and toxic for rabbits. Serotype M3 strains with the phage-encoded speK and sla genes increased dramatically in frequency late in the 20th century, commensurate with the rise in invasive disease caused by M3 organisms. Taken together, the results show that phage-mediated recombination has played a critical role in the emergence of a new, unusually virulent clone of serotype M3 GAS. superantigen | streptococcal pyrogenic exotoxin | comparative genomics

The skin provides both physical and immunological protection from the environment. Allergic reactions may produce redness or hives that resolve quickly or with symptomatic treatment. Contact dermatitis from metal in jewelry, poison oak, and cosmetics affects many people. Atopic dermatitis is a common allergic condition, particularly in children, characterized by chronic itching and redness. Mastocytosis describes conditions which produce red-brown lesions and other symptoms caused by excess mast cells in the skin. Pemphigus causes blistering from an immune reaction against the skin., The skin represents a unique immunologic organ poised to protect the host from invading organisms and environmental antigens. The skin is also an important target for a variety of allergic and autoimmune responses. Mast cells are key to the pathogenesis of urticaria, angioedema, and mastocytosis. Atopic dermatitis is the consequence of an immunoregulatory abnormality resulting in a skindirected T helper type 2 response. Allergic contact dermatitis is an example of classic delayed type hypersensitivity. Circulating autoantibodies against the epidermis are a key mechanism by which bullous skin diseases occur. JAMA. 1997;278:1914-1923

Superantigens, such as toxic shock syndrome toxin 1 (TSST-1), have been implicated in the pathogenesis of several autoimmune and allergic diseases associated with polyclonal B cell activation. In this report, we studied the in vitro effects of TSST-1 on B cell activation. We show herein that TSST-1 produced antagonistic effects on Ig synthesis by peripheral blood mononuclear cells (PBMC) from normal subjects, depending on the concentration used; Ig production was inhibited at 1000 pg/ml (P < 0.01) and enhanced at 1 and 0.01 pg/ml (P < 0.01) of toxin. Cultures of PBMC were then examined for morphologic features and DNA fragmentation characteristic for apoptosis. B cells exhibited a significantly higher (P < 0.01) incidence of apoptosis after stimulation with 1000 pg/ml of TSST-1 compared with 1 or 0.01 pg/ml of toxin or medium alone. Abundant expression of Fas, a cell surface protein that mediates apoptosis, was detected on B cells after stimulation with 1000 pg/ml of TSST-1 and was significantly higher on B cells undergoing apoptosis than on live cells (P = 0.01). Additionally, increased Fas expression and B cell death occurred at concentrations of TSST-1 inducing the production of high amounts of [Gamma] interferon (IFN-[Gamma]), and both events could be blocked by neutralizing anti-IFN-[Gamma] antibody. These findings suggest that high concentrations of TSST-1 can induce IFN-[Gamma]-dependent B cell apoptosis, whereas at low concentrations it stimulates Ig synthesis by PBMC from normal subjects. These findings support the concept that staphylococcal toxins have a role in B cell hyperactivity in autoimmunity and allergy.

Studies were carried out to determine whether the acute phase of Kawasaki disease (KD) is associated with the selective expansion of T cells expressing particular beta chain variable (Vbeta) gene segments. It was observed that patients in the acute phase of KD showed significantly elevated levels of Vbeta2- and Vbeta8.1-expressing T cells compared to the other control groups. Thus, the results suggest that KD may be caused by a superantigen.