Presence of IgE antibodies to staphylococcal exotoxins on the skin of patients with atopic dermatitis. Evidence for a new group of allergens

Patho-immunological mechanisms of atopic dermatitis: The role of the three major human microbiomes

Atopic dermatitis (AD) is a genetically predisposed allergic inflammatory dermatosis with chronic, pruritic, and recurrent features. Patients with AD have dry and itchy skin, often accompanied by chronic eczematous lesions, allergic rhinitis, or asthma, which has a considerable impact on their daily lives. With advances in genome sequencing technology, it has been demonstrated that microorganisms are involved in this disease, and the microorganisms associated with AD are attracting considerable research attention. An increasing number of studies conducted in recent years have demonstrated that an imbalanced microbiome in AD patients has substantial impact on disease prognosis, and the causes are closely tied to various immune mechanisms. However, the involvement of microorganisms in the pathogenesis of AD remains poorly understood. In this paper, we review the advances in research on the immunological mechanisms of the skin microbiome, intestinal microbiome, and lung microbiome that are related to AD prognosis and immunotherapy protocols. It is hoped that this approach will lay the foundation for exploring the pathogenesis of and emerging treatments for AD.

Adjuvant-independent airway sensitization and infection mouse models leading to allergic asthma

Asthma is a chronic respiratory disease of global importance. Mouse models of allergic asthma have been instrumental in advancing research and novel therapeutic strategies for patients. The application of relevant allergens and physiological routes of exposure in such models has led to valuable insights into the complexities of asthma onset and development as well as key disease mechanisms. Furthermore, environmental microbial exposures and infections have been shown to play a fundamental part in asthma pathogenesis and alter disease outcome. In this review, we delve into physiological mouse models of allergic asthma and explore literature reports on most significant interplays between microbial infections and asthma development with relevance to human disease.

Atopy in chronic urticaria: an important yet overlooked issue

Chronic urticaria (CU) is one of the most common dermatological diseases and has a significant impact on the quality of life of patients. However, the pathogenesis of this disease remains unclear. Autoimmunity in chronic spontaneous urticaria (CSU) has received considerable attention and has been studied previously. Atopy is an important characteristic of CU; however, it has not been fully recognized. Atopy predisposes individuals to immune responses to allergens, leading to type 2 inflammation and immunoglobulin E (IgE) overproduction. Compared with healthy individuals, patients with CU have a higher proportion of atopy, and an atopic background is correlated with the clinical characteristics of CU. The total IgE levels in patients with CU is significantly higher than those in healthy individuals. Although its level is not higher than that in classic allergic diseases, it is closely related to CU. Exogenous allergens, auto-allergens, and specific IgEs, which are closely related to atopy, have been reported, and their roles in CU pathogenesis are also being studied. Local and systemic atopic inflammation is present in patients with CU. This review summarizes the current knowledge regarding atopy and CU, speculating that there are CU subtypes, such as atopic CSU or atopic chronic inducible urticaria (CIndU) and that atopy may be involved in the pathogenesis of CU. These findings provide a new perspective for a comprehensive understanding of the clinical features of CU and further research regarding its pathogenesis.

Lipidomics and Metabolomics in Infant Atopic Dermatitis: What's the Correlation with Early Nutrition?

To date, the complex picture of atopic dermatitis (AD) has not yet been fully clarified, despite the important prevalence of this disease in the pediatric population (20%) and the possibility of persistence into adulthood, with important implications for the quality of life of those affected, as well as significant social and financial costs. The most recent scientific evidence suggests a new interpretation of AD, highlighting the important role of the environment, particularly that of nutrition in the early stages of development. In fact, the new indications seem to point out the harmful effect of elimination diets, except in rare cases, the uselessness of chrono-insertions during complementary feeding and some benefits, albeit weak, of breastfeeding in those at greater risk. In this context, metabolomics and lipidomics can be necessary for a more in-depth knowledge of the complex metabolic network underlying this pathology. In fact, an alteration of the metabolic contents in children with AD has been highlighted, especially in correlation to the intestinal microbiota. While preliminary lipidomic studies showed the usefulness of a more in-depth knowledge of the alterations of the skin barrier to improve the development of baby skin care products. Therefore, investigating the response of different allergic phenotypes could be useful for better patient management and understanding, thus providing an early intervention on dysbiosis necessary to regulate the immune response from the earliest stages of development.

Association between poly-sensitisation and sensitisation to staphylococcal enterotoxin A and B affecting allergic severity in children

PURPOSE

Accumulating evidence suggests that Staphylococcus aureus plays a significant role as a disease modifier in upper and lower airway diseases. We aimed to assess the association between staphylococcal enterotoxins (SEs) with allergic diseases and the degree of allergen sensitisation in children, which remains unclear.

METHODS

We retrospectively reviewed the medical records of 455 patients aged 3-18 years between March 2018 and March 2022. Clinical history and demographic data were obtained. The baseline study included paranasal sinus X-ray scan, multiple allergen simultaneous test, and ImmunoCAP® for measuring serum total and specific immunoglobulin E (IgE) levels to allergens and staphylococcal enterotoxin A and B (SEA and SEB).

RESULTS

The mean age was 9.77 ± 4.3 years. 133 patients (29.2%) were sensitised to one inhalant allergen, and 188 patients (41.3%) showed polysensitisation. Patients sensitised to SEs showed higher total and specific IgE levels and total eosinophil counts compared to non-SE-sensitised patients. Sensitisation to SEs is closely associated with polysensitisation to inhalant allergens and allergic multimorbidity. When the SE-IgE value was 0.35 or higher, the odds ratio for allergen polysensitisation was significantly higher than when the SE-IgE value was lower than 0.35.

CONCLUSIONS

Association between polysensitisation and sensitisation to SEs in children shows the higher the specific IgE levels for SEs, the higher the likelihood of polysensitisation. Considering the relationship between polysensitisation, high IgE levels, and the severity of allergic morbidity, sensitisation to SEs is thought to be related to allergy severity.

The feline skin microbiome: interrelationship between health and disease

PRACTICAL RELEVANCE

As with other species, the skin microbiome of cats has been assessed over the past few years utilizing modern technologies. This has resulted in the identification of many more bacterial and fungal organisms compared with what had been recorded historically on the skin in various states of health and disease using culture-based studies. This information is expanding the knowledge of how microbial communities are impacted by various changes in the skin health of cats. More specifically, how these microbial communities change in the face of health and disease, and how various therapeutic interventions affect the cutaneous microbiome, lends a greater understanding of disease pathogenesis and provides a growing area of research for correcting dysbiosis and improving feline skin health.

EVIDENCE BASE

Most studies on the feline skin microbiome thus far have been descriptive in nature. These provide a framework for the next level of investigations on how various states of health and disease impact the products produced by the cutaneous microbiome (ie, the cutaneous metabolome), as well as how targeted interventions may promote the restoration of balance.

AIMS

This review aims to summarize what is currently known about the feline cutaneous microbiome and its clinical implications. The role of the skin microbiome in health and disease, the current state of research in this area and the potential for future studies to produce targeted interventions for cats are a particular focus.

Staphylococcus aureus from Atopic Dermatitis Patients: Its Genetic Structure and Susceptibility to Phototreatment

We characterized the population of Staphylococcus aureus from patients with atopic dermatitis (AD) in terms of (i) genetic diversity, (ii) presence and functionality of genes encoding important virulence factors: staphylococcal enterotoxins (sea, seb, sec, sed), toxic shock syndrome 1 toxin (tsst-1), and Panton-Valentine leukocidin (lukS/lukF-PV) by spa typing, PCR, drug resistance profile determination, and Western blot. We then subjected the studied population of S. aureus to photoinactivation based on a light-activated compound called rose bengal (RB) to verify photoinactivation as an approach to effectively kill toxin-producing S. aureus. We have obtained 43 different spa types that can be grouped into 12 clusters, indicating for the first-time clonal complex (CC) 7 as the most widespread. A total of 65% of the tested isolates had at least one gene encoding the tested virulence factor, but their distribution differed between the group of children and adults, and between patients with AD and the control group without atopy. We detected a 3.5% frequency of methicillin-resistant strains (MRSA) and no other multidrug resistance. Despite genetic diversity and production of various toxins, all isolates tested were effectively photoinactivated (bacterial cell viability reduction ≥ 3 log10 units) under safe conditions for the human keratinocyte cell line, which indicates that photoinactivation can be a good option in skin decolonization. IMPORTANCE Staphylococcus aureus massively colonizes the skin of patients with atopic dermatitis (AD). It is worth noting that the frequency of detection of multidrug-resistant S. aureus (MRSA) in AD patients is higher than the healthy population, which makes treatment much more difficult. Information about the specific genetic background of S. aureus accompanying and/or causing exacerbations of AD is of great importance from the point of view of epidemiological investigations and the development of possible treatment options.

Staphylococcal Enterotoxin-Specific IgE Sensitization: A Potential Predictor of Fixed Airflow Obstruction in Elderly Asthma

PURPOSE

Staphylococcus aureus enterotoxin-specific immunoglobulin E (SE-sIgE) sensitization tends to increase with age and is known to be associated with asthma and severity in older adults. However, the long-term impact of SE-sIgE in the elderly remains unknown. This study aimed to examine the relationships between SE-sIgE and fixed airflow obstruction (FAO) in a cohort of elderly asthmatics.

METHODS

A total of 223 elderly asthmatics and 89 controls were analyzed. Patients were assessed for demographics, history of chronic rhinosinusitis (CRS), asthma duration, acute exacerbation frequency, and lung function at baseline and then were prospectively followed up for 2 years. Serum total IgE and SE-sIgE levels were measured at baseline. Airflow obstruction was defined as forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio < 0.7 at baseline and FAO was defined as FEV1/FVC ratio < 0.7 over the 2-year follow-up.

RESULTS

At baseline, the prevalence of airflow obstruction was 29.1%. Patients with airflow obstruction were significantly more likely to be male, and have a positive smoking history, comorbid CRS, and higher levels of SE-sIgE than those without airflow obstruction. Multivariate logistic regression analysis showed that airflow obstruction was significantly associated with current smoking and SE-sIgE sensitization at baseline. After the 2-year follow-up, baseline SE-sIgE sensitization was consistently related to FAO. Meanwhile, the number of exacerbations per year was significantly correlated with SE-sIgE levels.

CONCLUSIONS

Baseline SE-sIgE sensitization was significantly associated with the number of asthma exacerbations and FAO after the 2-year follow-up in elderly asthmatics. These findings warrant further investigation of the direct and mediating roles of SE-sIgE sensitization on airway remodeling.

The Role of Staphylococcus aureus and Its Toxins in the Pathogenesis of Allergic Asthma

Bronchial asthma is one of the most common chronic diseases worldwide and affects more than 300 million patients. Allergic asthma affects the majority of asthmatic children as well as approximately 50% of adult asthmatics. It is characterized by a Th2-mediated immune response against aeroallergens. Many aspects of the overall pathophysiology are known, while the underlying mechanisms and predisposing factors remain largely elusive today. Over the last decade, respiratory colonization with Staphylococcus aureus (S. aureus), a Gram-positive facultative bacterial pathogen, came into focus as a risk factor for the development of atopic respiratory diseases. More than 30% of the world’s population is constantly colonized with S. aureus in their nasopharynx. This colonization is mostly asymptomatic, but in immunocompromised patients, it can lead to serious complications including pneumonia, sepsis, or even death. S. aureus is known for its ability to produce a wide range of proteins including toxins, serine-protease-like proteins, and protein A. In this review, we provide an overview of the current knowledge about the pathophysiology of allergic asthma and to what extent it can be affected by different toxins produced by S. aureus. Intensifying this knowledge might lead to new preventive strategies for atopic respiratory diseases.

Superantigens, a Paradox of the Immune Response

Staphylococcal enterotoxins are a wide family of bacterial exotoxins with the capacity to activate as much as 20% of the host T cells, which is why they were called superantigens. Superantigens (SAgs) can cause multiple diseases in humans and cattle, ranging from mild to life-threatening infections. Almost all S. aureus isolates encode at least one of these toxins, though there is no complete knowledge about how their production is triggered. One of the main problems with the available evidence for these toxins is that most studies have been conducted with a few superantigens; however, the resulting characteristics are attributed to the whole group. Although these toxins share homology and a two-domain structure organization, the similarity ratio varies from 20 to 89% among different SAgs, implying wide heterogeneity. Furthermore, every attempt to structurally classify these proteins has failed to answer differential biological functionalities. Taking these concerns into account, it might not be appropriate to extrapolate all the information that is currently available to every staphylococcal SAg. Here, we aimed to gather the available information about all staphylococcal SAgs, considering their functions and pathogenicity, their ability to interact with the immune system as well as their capacity to be used as immunotherapeutic agents, resembling the two faces of Dr. Jekyll and Mr. Hyde.

Scientific and Practical Innovations in Restoring Skin Barrier Properties in Children with Atopic Dermatitis

Atopic dermatitis (AD) is a multifactorial inflammatory skin disease. Its pathogenetic basis is epidermal barrier dysfunction, immune system dysregulation, as well as skin microbiome diversity decrease that occurs due to genetic predisposition. Considering these factors, the skin of patients with AD requires constant care and use of medications with active regenerative properties. The inclusion of anti-inflammatory components in the composition of modern emollients (zinc sulfate and sucralfate) is crucial for restoring the microbiome and immune mechanisms controlling the skin. This article presents data on pathogenetic applicability and clinical efficacy of emollients with anti-inflammatory compounds in patients with AD.

Characteristics of the Skin Microbiome in Selected Dermatological Conditions: A Narrative Review

The skin is the largest and outermost organ of the human body. The microbial diversity of the skin can be influenced by several variable factors such as physiological state, lifestyle, and geographical locations. Recent years have seen increased interest in research aiming at an improved understanding of the relationship between the human microbiota and several diseases. Albeit understudied, interesting correlations between the skin microbiota and several dermatological conditions have been observed. Studies have shown that a decrease or increase in the abundance of certain microbial communities can be implicated in several dermatological pathologies. This narrative review (i) examines the role of the skin microbiota in the maintenance of skin homeostasis and health, (ii) provides examples on how some common skin diseases (acne inversa, candidiasis, psoriasis) are associated with the dysbiosis of microbial communities, and (iii) describes how recent research approaches used in skin microbiome studies may lead to improved, more sensitive diagnostics and individual therapeutics in the foreseeable future.

Type 2 Inflammation Contributes to Skin Barrier Dysfunction in Atopic Dermatitis

Skin barrier dysfunction, a defining feature of atopic dermatitis (AD), arises from multiple interacting systems. In AD, skin inflammation is caused by host-environment interactions involving keratinocytes as well as tissue-resident immune cells such as type 2 innate lymphoid cells, basophils, mast cells, and T helper type 2 cells, which produce type 2 cytokines, including IL-4, IL-5, IL-13, and IL-31. Type 2 inflammation broadly impacts the expression of genes relevant for barrier function, such as intracellular structural proteins, extracellular lipids, and junctional proteins, and enhances Staphylococcus aureus skin colonization. Systemic anti‒type 2 inflammation therapies may improve dysfunctional skin barrier in AD.

Specific T cells targeting Staphylococcus aureus fibronectin-binding protein 1 induce a type 2/type 1 inflammatory response in sensitized atopic dermatitis patients

BACKGROUND

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases worldwide and Staphylococcus aureus colonization and secondary infections occur in the majority of AD patients. Allergic sensitizations against microbial antigens have been discussed as possible trigger factors of AD. Recently, we reported IgE sensitization against fibronectin-binding protein 1 (FBP1), an essential virulence component in S. aureus, in a subgroup of patients suffering from AD. To expand these findings by investigating delayed-type immune reactions, the objective of this study was to detect and phenotypically characterize FBP1-specific T cells as possible trigger factors in AD.

METHODS

Immunodominant T-cell epitopes were mapped by proliferation testing of patient-derived FBP1-specific T-cell lines after stimulation with single 15mer peptides, which were derived from different functional domains of the FBP1 sequence. Major histocompatibility complex class II tetramers carrying immunodominant epitopes successfully stained T helper cells in 8 out of 8 HLA-matched, IgE-sensitized AD patients.

RESULTS

Cytokine profiling of multimer-sorted cells revealed that predominantly the type 2 cytokines IL-13 and IL-4 were secreted by these cells. In contrast, IL-17, the marker cytokine for response to extracellular pathogens, was scarcely detectable.

CONCLUSIONS

We demonstrate that FBP1 contains immunodominant peptides that induce a specific pro-inflammatory T helper cell response with increased Th2 levels that can drive an allergic inflammation in sensitized AD patients.

Effects of Growth Stage on the Characterization of Enterotoxin A-Producing Staphylococcus aureus‐Derived Membrane vesicles

Virulence factors, such as staphylococcal enterotoxin A (SEA), are contained within membrane vesicles (MVs) in the cell membrane of Staphylococcus aureus. In this study, the effects of the growth stage on quantitative and qualitative changes in the components contained in the MVs of S. aureus SEA-producing strains were examined. Changes in the expression levels of S. aureus genes were examined at each growth stage; phenol-soluble modulin (PSM) gene reached a maximum after 8 h, and the expression of cell membrane-related genes was decreased after 6 h. Based on these gene expression patterns, MVs were prepared at 6, 17, and 24 h. The particle size of MVs did not change depending on the growth stage. MVs prepared after culture for 17 h maintained their particle size when stored at 23 °C. The amount of SEA in the culture supernatant and MVs were not correlated. Bifunctional autolysin, a protein involved in cell wall biosynthesis/degradation, was increased in MVs at 17 h. The expression pattern of inflammation-related genes in human adult low calcium high temperature (HaCaT) cells induced by MVs was different for each growth stage. The inclusion components of S. aureus-derived MVs are selective, depend on the stage of growth, and may play an important role in toxicity.

Multiple Roles for Cytokines in Atopic Dermatitis: From Pathogenic Mediators to Endotype-Specific Biomarkers to Therapeutic Targets

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases, which generally presents with intense itching and recurrent eczematous lesions. AD affects up to 20% of children and 10% of adults in high-income countries. The prevalence and incidence of AD have increased in recent years. The onset of AD mostly occurs in childhood, although in some cases AD may persist in adult life or even manifest in middle age (adult-onset AD). AD pathophysiology is made of a complex net, in which genetic background, skin barrier dysfunction, innate and adaptive immune responses, as well as itch contribute to disease development, progression, and chronicization. One of the most important features of AD is skin dehydration, which is mainly caused by filaggrin mutations that determine trans-epidermal water loss, pH alterations, and antigen penetration. In accordance with the “outside-inside” theory of AD pathogenesis, in a context of an altered epidermal barrier, antigens encounter epidermal antigen presentation cells (APCs), such as epidermal Langerhans cells and inflammatory epidermal dendritic cells, leading to their maturation and Th-2 cell-mediated inflammation. APCs also bear trimeric high-affinity receptors for immunoglobulin E (IgE), which induce IgE-mediated sensitizations as part of pathogenic mechanisms leading to AD. In this review, we discuss the role of cytokines in the pathogenesis of AD, considering patients with various clinical AD phenotypes. Moreover, we describe the cytokine patterns in patients with AD at different phases of the disease evolution, as well as in relation to different phenotypes/endotypes, including age, race, and intrinsic/extrinsic subtypes. We also discuss the outcomes of current biologics for AD, which corroborate the presence of multiple cytokine axes involved in the background of AD. A deep insight into the correlation between cytokine patterns and the related clinical forms of AD is a crucial step towards increasingly personalized, and therefore more efficient therapy.

Model-based meta-analysis to optimise S. aureus-targeted therapies for atopic dermatitis

Several clinical trials of Staphylococcus aureus (S. aureus)‒targeted therapies for atopic dermatitis (AD) have shown conflicting results about whether they improve AD severity scores. This study performs a model-based meta-analysis to investigate the possible causes of these conflicting results and suggests how to improve the efficacies of S. aureus‒targeted therapies. We developed a mathematical model that describes systems-level AD pathogenesis involving dynamic interactions between S. aureus and coagulase-negative Staphylococcus (CoNS). Our model simulation reproduced the clinically observed detrimental effects of the application of S. hominis A9 and flucloxacillin on AD severity and showed that these effects disappeared if the bactericidal activity against CoNS was removed. A hypothetical (modeled) eradication of S. aureus by 3.0 log₁₀ colony-forming unit per cm² without killing CoNS achieved Eczema Area and Severity Index 75 comparable with that of dupilumab. This efficacy was potentiated if dupilumab was administered in conjunction with S. aureus eradication (Eczema Area and Severity Index 75 at week 16) (S. aureus eradication: 66.7%, dupilumab 61.6% and combination 87.8%). The improved efficacy was also seen for virtual dupilumab poor responders. Our model simulation suggests that killing CoNS worsens AD severity and that S. aureus‒specific eradication without killing CoNS could be effective for patients with AD, including dupilumab poor responders. This study will contribute to designing promising S. aureus‒targeted therapy.

Disorders of the skin microbiome in atopic dermatitis and psoriasis

The notion of skin microbiome encompasses a heterogeneous group of microorganisms that belong to various taxonomic units, such as bacteria, archaea, viruses, and fungi. The impact of these microbial community constituents upon the epidermal barrier condition, and upon the immune system functioning, is being intensely scrutinized. There is a particular interest in studying the role that the microorganisms of genus Staphylococcus spp. play in the course of physiological and pathological processes occurring in the skin. This review examines in detail the interaction of the microorganisms of genus Staphylococcus spp. with the microbial community constituents, as well as with the skin immune system in normal condition and in the condition associated with inflammatory dermatoses. There are also the data given on S. aureus pathogenicity factors, the data on the impact of this microorganism upon the course of atopic dermatitis, and upon the course of psoriasis. The review examines the role that coagulase-negative staphylococci, S. epidermidis in particular, play in maintaining the microbiome homeostasis. The review as well examines the impact of the skin microbiome upon the development and activity of the skin immune system, and upon maintaining the integrity of the epidermal barrier.

Updated understanding of Staphylococcus aureus in atopic dermatitis: From virulence factors to commensals and clonal complexes

Atopic dermatitis (AD) is a common inflammatory dermatosis that has multiple contributing factors including genetic, immunologic and environmental. Staphylococcus aureus (SA) has long been associated with exacerbation of AD. SA produces many virulence factors that interact with the human skin and immune system. These superantigens and toxins have been shown to contribute to adhesion, inflammation and skin barrier destruction. Recent advances in genome sequencing techniques have led to a broadened understanding of the multiple ways SA interacts with the cutaneous environment in AD hosts. For example, temporal shifts in the microbiome, specifically in clonal complexes of SA, have been identified during AD flares and remission. Herein, we review mechanisms of interaction between the cutaneous microbiome and SA and highlight known differences in SA clonal complexes that contribute to AD pathogenesis. Detailed knowledge of the genetic strains of SA and cutaneous dysbiosis is becoming increasingly relevant in paving the way for microbiome-modulating and precision therapies for AD.

Keratin 17 in psoriasis: Current understanding and future perspectives

Keratin 17 (K17) is a multifaceted cytoskeletal protein that is not commonly expressed in the epidermis under normal physiological conditions. However, in psoriasis, K17 is overexpressed in the suprabasal layer of the epidermis and plays an important role in the pathogenesis of the disease. In this review, we have summarized our findings and those reported in other studies concerning the pathogenic functions of K17, as well as the mechanisms underlying the increase in K17 expression in psoriasis. K17 exerts both pro-proliferative and pro-inflammatory effects on keratinocytes. Moreover, K17 peptides trigger autoreactive T cells and promote psoriasis-related cytokine production. In turn, these cytokines modulate the expression, stability, and protein-protein interactions of K17 through transcriptional and translational regulation and post-translational modification of K17 in keratinocytes. Thus, a K17/T-cell/cytokine autoimmune loop is implicated in the pathogenesis of psoriasis, which is supported by the fact that therapies targeting K17 have achieved good outcomes in psoriasis-like mouse models. Future perspectives of K17 in psoriasis have also been discussed to provide potential directions for further studies.

Emerging Nanomedicines for the Treatment of Atopic Dermatitis

Globally, the prevalence of Atopic dermatitis (AD) is significantly increasing and affecting around 20% of population including children. Complex interactions amongst abnormality in epidermal barrier function, environment, infectious agents and immunological defects are considered as key factors in the pathogenesis of AD. Although the role of oxidative stress has been studied in some skin diseases, investigation of the same in AD is intermittent. Calcineurin inhibitors and/or topical corticosteroids are currently available; however, it causes atrophy of the skin, burning sensation, and systemic side effects which leads to poor patient compliance. These limitations provoke the strong need to develop an innovative approach in managing AD. Nanomaterials for effective drug delivery to skin conditions such as AD have attracted a lot of attention owing to its ability to encapsulate, protect, and release the cargo at the diseased skin site. However, there are lots of unmet challenges especially in terms of development of non-toxic formulations and clinical translation of established nanomedicines in the form of accessible products. Numerous formulations have emerged as carrier for poorly soluble and permeable drugs, viz., lipidic, polymeric, metal, silica, liposomes, hydrocarbon gels and this field is evolving. This review is intended to provide an insight incidences associated with pathophysiology of AD and challenges with existing treatments of AD. Focus is kept on reviewing current development and emerging nanomedicines for effective treatment of AD. The review also inculcates merits of several nanomedicines in overcoming challenges of existing products and its future implications.

Colonization With Staphylococcus aureus in Atopic Dermatitis Patients: Attempts to Reveal the Unknown

Atopic dermatitis (AD) patients are massively colonized with Staphylococcus aureus (S. aureus) in lesional and non-lesional skin. A skin infection may become systemic if left untreated. Of interest, the incidence of multi-drug resistant S. aureus (MRSA) in AD patients is higher as compared to a healthy population, which makes treatment even more challenging. Information on the specific genetic background of S. aureus accompanying and/or causing AD flares would be of great importance in terms of possible treatment option development. In this review, we summarized the data on the prevalence of S. aureus in general in AD skin, and the prevalence of specific clones that might be associated with flares of eczema. We put our special interest in the presence and role of staphylococcal enterotoxins as important virulence factors in the epidemiology of AD-derived S. aureus. Also, we summarize the present and potentially useful future anti-staphylococcal treatment.

On Two Cases with Autosomal Dominant Hyper IgE Syndrome: Importance of Immunological Parameters for Clinical Course and Follow-Up

Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare disease described in 1966. It is characterized by severe dermatitis, a peculiar face, frequent infections, extremely high levels of serum IgE and eosinophilia, all resulting from a defect in the STAT3 gene. A variety of mutations in the SH2 and DNA-binding domain have been described, and several studies have searched for associations between the severity of the clinical symptoms, laboratory findings, and the type of genetic alteration. We present two children with AD-HIES–a girl with the most common STAT3 mutation (R382W) and a boy with a rare variant (G617E) in the same gene, previously reported in only one other patient. Herein, we discuss the clinical and immunological findings in our patients, focusing on their importance on disease course and management.

Basophil activation test for Staphylococcus aureus enterotoxins in severe asthmatic patients

BACKGROUND

Several studies have shown an association between severe asthma and serum immunoglobulins E (IgE) against Staphylococcus aureus enterotoxins (SEs). SEs-the prototypes being types A (SEA), B (SEB) and toxic shock syndrome toxin 1 (TSST-1)-can induce both polyclonal and specific IgE responses.

OBJECTIVE

The aim of the study was to evaluate the ability of SEs to induce basophil activation in severe asthmatic patients using the basophil activation test (BAT).

METHODS

57 severe asthmatic patients were enrolled. BAT in response to SEA, SEB and TSST-1 was performed in all patients, while serum IgE to SEA, SEB and SEC was available in 49 patients. BAT was considered positive when CD203c+ basophils to SEs were ≥5%, and the stimulation index (SI, ratio between % of CD203c+ basophils to SEs and to negative control) was >2. Two threshold values (>0.1 kU/L and >0.35 kU/L, respectively) were used to assess serum SEsIgE.

RESULTS

36.8% of severe asthmatic patients had a BAT positive for at least one SE (BAT SEs+). Serum SEsIgE >0.35 kU/L (SEs IgE+) was associated with BAT SEs positivity. Among patients with negative skin prick test, 35% were BAT SEs+, 30% SEs IgE+, 55% BAT or IgE- SEs+. A negative correlation between SI of BAT to SEs and both clinical (ACT score) and functional parameters was observed, together with a positive correlation of BAT with asthma exacerbations.

CONCLUSIONS

The positivity of BAT for SEs in a subgroup of severe asthmatic patients further supports the pathogenic role of Staphylococcus aureus in severe asthma.

Role of Antimicrobial Peptides in Skin Barrier Repair in Individuals with Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that exhibits a complex interplay of skin barrier disruption and immune dysregulation. Patients with AD are susceptible to cutaneous infections that may progress to complications, including staphylococcal septicemia. Although most studies have focused on filaggrin mutations, the physical barrier and antimicrobial barrier also play critical roles in the pathogenesis of AD. Within the physical barrier, the stratum corneum and tight junctions play the most important roles. The tight junction barrier is involved in the pathogenesis of AD, as structural and functional defects in tight junctions not only disrupt the physical barrier but also contribute to immunological impairments. Furthermore, antimicrobial peptides, such as LL-37, human b-defensins, and S100A7, improve tight junction barrier function. Recent studies elucidating the pathogenesis of AD have led to the development of barrier repair therapy for skin barrier defects in patients with this disease. This review analyzes the association between skin barrier disruption in patients with AD and antimicrobial peptides to determine the effect of these peptides on skin barrier repair and to consider employing antimicrobial peptides in barrier repair strategies as an additional approach for AD management.

Which Way Do We Go? Complex Interactions in Atopic Dermatitis Pathogenesis

Atopic dermatitis (AD) is a common, chronic, inflammatory skin condition characterized by recurrent and pruritic skin eruptions. Multiple factors contribute to the pathogenesis of AD, including skin barrier dysfunction, microbial dysbiosis, and immune dysregulation. Interactions among these factors form a complex, multidirectional network that can reinforce atopic skin disease but can also be ameliorated by targeted therapies. This review summarizes the complex interactions among contributing factors in AD and the implications on disease development and therapeutic interventions.

Food allergy and atopic dermatitis

Atopic dermatitis (AD), characterized by intense pruritus, eczematous lesions, and a relapsing disease course, is a chronic inflammatory skin disease that affects both children and adults. AD often begins in infancy and is associated with atopic diseases in the personal or family history.1 Environmental factors may trigger AD by affecting the skin barrier and by triggering inflammation. The elicitation of T-helper type 2 cytokines further impairs the epidermal barrier and leads to the penetration of irritants and allergens into the epidermis and thereby perpetuating inflammation. The presence of AD and its severity has been shown to positively correlate with risk of developing food allergy (FA). Children with AD are estimated to be six times more likely to develop FA compared with their healthy peers. It has been reported that nearly 40% of children with moderate-to-severe AD have immunoglobulin E (IgE) mediated FA compared with only 6% in the general population. Although analysis of experimental data has linked skin inflammation in AD to FA, with food challenges reproducing symptoms and avoidance diets improving AD, elimination diets are not known to cure AD and may have unfavorable consequences, such as loss of tolerance, which leads to immediate-type allergy, including anaphylaxis, nutritional deficiencies, growth failure, and reduction of quality of life for the patient and family. Exacerbation of AD can be inaccurately attributed to foods. Individuals with AD are often sensitized to foods with positive testing results, however, able to tolerate the food. In light of widespread ordering and commercial availability of serum specific IgE for FA, testing for FA is recommended only if, from a detailed clinical history, immediate-type allergic symptoms occur with ingestion of food, or in infants with AD who do not improve with optimal skin care.

Histoire naturelle de la dermatite atopique

Atopic dermatitis (AD) is a common frequent chronic inflammatory skin disease which begins frequently in infancy. The clinical expression of AD is a recurrent eczema on a dry skin. AD is a multifactorial disease characterized by two linked abnormalities: a skin barrier defect and a cellular inflammation, with type-2 main components. However, the pathophysiology of AD is not as simple as this description looks like. In this review, we will present a synthesis of current knowledge on natural history of AD and the involved factors, in order to clarify AD care. The evolution of AD is associated with many atopic comorbidities, following the "atopic march" scheme: IgE-mediated food allergy, allergic asthma and rhinitis occurring classically after AD. In fact, this is rarely the case, but the atopic march seems to be associated with AD severity. AD has also many neuropsychological complications which are essential to be detected. Other factors could influence the natural history of AD: genetic mutations on different genes (proteins of skin barrier, innate and adaptive immunity pathways), skin dysbiosis with colonization by Staphylococcus aureus, sensitization against environmental proteins. AD treatment is based on the restauration of the skin barrier using emollients and on anti-inflammatory drugs (notably topical corticosteroids) during the inflammatory flares. It is not recommended to treat the skin colonization by S. aureus, excepted in case of skin infection. The probiotics have no efficiency as curative treatment of AD, but could have an interest for the primary prevention, especially in at-risk populations. © 2019 Elsevier Masson SAS. All rights reserved.

The clinical impact of cross-reactions between allergens on allergic skin diseases

PURPOSE OF REVIEW

The route of allergen sensing via the skin appears to influence the immune system towards mounting a type 2 response, especially in genetically predisposed individuals. Allergens recognized this way may derive from microbial, animal, food, or other plant sources and trigger atopic dermatitis. Allergens can be grouped into families depending on their structure and function, harboring significant structural and sequence similarities. Cross-reactivity between allergens is believed to arise as a consequence, and to underlie the development of further atopic diseases.

RECENT FINDINGS

Especially for the plant allergens of the families of PR10-related proteins and profilins, immune cross-reactions have been described. Actual studies support that food and pollen allergens can aggravate skin lesions in patients suffering from atopic dermatitis. Further on, allergens derived from air-borne or skin-borne fungi belong to common allergen families and bear cross-reactivity potential. Cross-reactivity to human homologous proteins, so-called autoallergens, is discussed to contribute to the chronification of atopic dermatitis.

SUMMARY

Due to high evolutionary conservation, allergic reactions can be triggered by highly homologous members of allergen families on the humoral as well as on the cellular level.

Biotherapeutic Approaches in Atopic Dermatitis

The skin microbiome plays a central role in inflammatory skin disorders such as atopic dermatitis (AD). In AD patients, an imbalance between pathogenic Staphylococcus aureus (S. aureus) and resident skin symbionts creates a state of dysbiosis which induces immune dysregulation and impairs skin barrier function. There are now exciting new prospects for microbiome-based interventions for AD prevention. In the hopes of achieving sustained control and management of disease in AD patients, current emerging biotherapeutic strategies aim to harness the skin microbiome associated with health by restoring a more diverse symbiotic skin microbiome, while selectively removing pathogenic S. aureus. Examples of such strategies are demonstrated in skin microbiome transplants, phage-derived anti-S. aureus endolysins, monoclonal antibodies, and quorum sensing (QS) inhibitors. However, further understanding of the skin microbiome and its role in AD pathogenesis is still needed to understand how these biotherapeutics alter the dynamics of the microbiome community; to optimize patient selection, drug delivery, and treatment duration; overcome rapid recolonization upon treatment cessation; and improve efficacy to allow these therapeutic options to eventually reach routine clinical practice.

Allergy-A New Role for T Cell Superantigens of Staphylococcus aureus?

Staphylococcus aureus superantigens (SAgs) are among the most potent T cell mitogens known. They stimulate large fractions of T cells by cross-linking their T cell receptor with major histocompatibility complex class-II molecules on antigen presenting cells, resulting in T cell proliferation and massive cytokine release. To date, 26 different SAgs have been described in the species S. aureus; they comprise the toxic shock syndrome toxin (TSST-1), as well as 25 staphylococcal enterotoxins (SEs) or enterotoxin-like proteins (SEls). SAgs can cause staphylococcal food poisoning and toxic shock syndrome and contribute to the clinical symptoms of staphylococcal infection. In addition, there is growing evidence that SAgs are involved in allergic diseases. This review provides an overview on recent epidemiological data on the involvement of S. aureus SAgs and anti-SAg-IgE in allergy, demonstrating that being sensitized to SEs—in contrast to inhalant allergens—is associated with a severe disease course in patients with chronic airway inflammation. The mechanisms by which SAgs trigger or amplify allergic immune responses, however, are not yet fully understood. Here, we discuss known and hypothetical pathways by which SAgs can drive an atopic disease.

Epicutaneous sensitization to food allergens in atopic dermatitis: What do we know?

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly affecting children, which has no definitive curative therapy apart from natural outgrowing. AD is persistent in 30%-40% of children. Epithelial barrier dysfunction in AD is a significant risk factor for the development of epicutaneous food sensitization, food allergy, and other allergic disorders. There is evidence that prophylactic emollient applications from birth may be useful for primary prevention of AD, but biomarkers are needed to guide cost-effective targeted therapy for high-risk individuals. In established early-onset AD, secondary preventive strategies are needed to attenuate progression to other allergic disorders such as food allergy, asthma, and allergic rhinitis (the atopic march). This review aims to describe the mechanisms underpinning the development of epicutaneous sensitization to food allergens and progression to clinical food allergy; summarize current evidence for interventions to halt the progression from AD to food sensitization and clinical food allergy; and highlight unmet needs and directions for future research.

Are avoidance diets still warranted in children with atopic dermatitis?

Nearly 40% of children with moderate-to-severe atopic dermatitis (AD) have IgE-mediated food allergy (FA). This clinical observation has been extensively documented by experimental data linking skin inflammation in AD to FA, as well as by food challenges reproducing symptoms and avoidance diets improving AD. Although food avoidance may improve AD, avoidance diets do not cure AD, may even have detrimental effects such as progression to immediate-type allergy including anaphylactic reactions, and may significantly reduce the quality of life of the patient and the family. AD care should focus upon optimal medical management, rather than dietary elimination. Food allergy testing is primarily indicated when immediate-type allergic reactions are a concern. In recalcitrant AD, if food is being considered a possible chronic trigger, a limited panel of foods may be tested. An avoidance diet is only indicated in patients clearly identified as food allergic by an appropriate diagnostic food challenge, and after adequately informing the family of the limited benefits, and possible harms of an elimination diet.

The role of bacterial skin infections in atopic dermatitis: expert statement and review from the International Eczema Council Skin Infection Group

Patients with atopic dermatitis (AD) have an increased risk of bacterial skin infections, which cause significant morbidity and, if untreated, may become systemic. Staphylococcus aureus colonizes the skin of most patients with AD and is the most common organism to cause infections. Overt bacterial infection is easily recognized by the appearance of weeping lesions, honey‐coloured crusts and pustules. However, the wide variability in clinical presentation of bacterial infection in AD and the inherent features of AD – cutaneous erythema and warmth, oozing associated with oedema, and regional lymphadenopathy – overlap with those of infection, making clinical diagnosis challenging. Furthermore, some features may be masked because of anatomical site‐ and skin‐type‐specific features, and the high frequency of S. aureus colonization in AD makes positive skin swab culture of suspected infection unreliable as a diagnostic tool. The host mechanisms and microbial virulence factors that underlie S. aureus colonization and infection in AD are incompletely understood. The aim of this article is to present the latest evidence from animal and human studies, including recent microbiome research, to define the clinical features of bacterial infections in AD, and to summarize our current understanding of the host and bacterial factors that influence microbial colonization and virulence.

The Microbiome and Atopic Dermatitis: A Review

The microbiome is defined as the sum of microbes, their genomes, and interactions in a given ecological niche. Atopic dermatitis is a multifactorial chronic inflammatory skin disease leading to dryness and itchiness of the skin. It is often associated with comorbidities such as allergic rhinoconjunctivitis and asthma. Today, culture-free techniques have been established to define microbes and their genomes that may be both detrimental and beneficial for their host. There are signs that microbes, both on skin and in the gut, may influence the course of atopic dermatitis. Antiseptic treatment has been used for decades, however now, with the help of traditional culture-based methods and modern metagenomics, we are beginning to understand that targeted treatment of dysbiosis may possibly become part of an integrated therapy plan in the future.

Insights into atopic dermatitis gained from genetically defined mouse models

Atopic dermatitis (AD) is characterized by severe pruritus and recurrent eczema with a chronic disease course. Impaired skin barrier function, hyperactivated T_H2 cell-type inflammation, and pruritus-induced scratching contribute to the disease pathogenesis of AD. Skin microbial alterations complicate the pathogenesis of AD further. Mouse models are a powerful tool to analyze such intricate pathophysiology of AD, with a caution that anatomy and immunology of the skin differ between human subjects and mice. Here we review recent understanding of AD etiology obtained using mouse models, which address the epidermal barrier, skin microbiome, T_H2 immune response, and pruritus.

The role of Staphylococcus aureus in atopic dermatitis: microbiological and immunological implications

Introduction

Atopic dermatitis (AD) is an inflammatory disease characterised by chronic and recurrent course. Its predominant symptom is skin pruritus. Therefore, many AD patients have recurrent skin infections and are susceptible to the colonisation of apparently healthy skin and nasal vestibule by Staphylococcus aureus (S. aureus). Some S. aureus strains are capable of producing exotoxins.

Aim

To assess the relation between the total IgE (tIgE) and asIgE targeted against SEA (SEA-sIgE) and SEB (SEB-sIgE), as indicators of the severity of the course of AD, and the presence of S. aureus on apparently healthy skin, in skin lesions and in the nasal vestibule.

Material and methods

The research was performed in a population of 134 AD patients (61 men and 73 women) aged 2–86 years. Three smears were collected for microbiological investigations: from the nasal vestibule, from the skin where lesions appeared at the moment of investigations and from the skin which was free from the eczema. On collection the material was cultured on solid and broth mediums. After incubation each medium was thoroughly analysed for the presence of S. aureus.

Results

There was a statistically significant correlation between healthy skin colonisation by S. aureus and increased SEA-sIgE. The same correlation was proved between healthy skin colonisation by S. aureus and increased SEB-sIgE. There was a statistically significant correlation between colonisation of the nasal vestibule by S. aureus and the SEA-sIgE and SEB-sIgE serum concentration.

Conclusions

It seems that the colonisation of the lesioned skin, healthy skin and the anterior nares by S. aureus is related with higher tIgE serum concentration, which translates to more severe course of the disease. Significantly increased SEA-IgE and SEB-IgE concentrations were observed in the patients whose tIgE serum concentration was statistically higher.

Staphylococcus Aureus in chronic airway diseases: An overview

This review investigates about the role of Staphylococcus Aureus (S. aureus) and S. aureus enterotoxins (SEs) in the pathogenesis of several chronic airway diseases. S. aureus is part of normal human flora and may colonize the skin and the upper airways. SEs acting as superantigens can induce an intense T cell activation and through the release of interleukin (IL) - 4, 5, and 13, can promote a polyclonal IgE response and eosinophilic inflammation. S. aureus can damage epithelial cells inducing the release of the so-called "alarmins" responsible of the activation of Type 2 innate lymphoid cells (ILC-2) linked to an IL-5 mediated airway eosinophilic inflammation. SEs sensitization has been recently associated with the eosinophilic endotypes of both nasal polyps and late onset severe asthma. Studies investigating the effect of biological therapies in SEs sensitized patients should be performed in order to better define the role played by S. aureus in the different endotypes of severe asthma and/or chronic rhinosinusitis.

Basophil-derived tumor necrosis factor can enhance survival in a sepsis model in mice

Basophils are evolutionarily conserved in vertebrates, despite their small numbers and short lifespan, suggesting that basophils have beneficial roles in maintaining health. However, these roles are not fully defined. Here, we demonstrate that basophil-deficient mice exhibited reduced bacterial clearance, and increased morbidity and mortality, in the cecal ligation and puncture (CLP) model of sepsis. Among the several pro-inflammatory mediators we measured, tumor necrosis factor (TNF) was the only cytokine that was significantly reduced in basophil-deficient mice after CLP. In accordance with that observation, we found that mice with genetic ablation of Tnf in basophils exhibited reduced systemic TNF concentrations during endotoxemia. Moreover, during CLP, mice whose basophils could not produce TNF exhibited reduced neutrophil and macrophage TNF production and effector functions, reduced bacterial clearance, and increased mortality. Taken together, our studies show that basophils can enhance the innate immune response against bacterial infection and help prevent sepsis.

Antibiotic choice and methicillin-resistant Staphylococcus aureus rate in children hospitalized for atopic dermatitis

BACKGROUND

Systemic antibiotics are commonly used in hospitalized patients with severe atopic dermatitis (AD) exacerbation. However, the antibiotic prescribing patterns are unclear.

OBJECTIVE

To compare the prescribing patterns of antibiotics for children who were hospitalized for AD exacerbation and infectious complications.

METHODS

Electronic medical records were reviewed for patients younger than 18 years who were hospitalized for AD exacerbation or infectious complications based on International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, Tenth Revision, Clinical Modification codes from 2003 to 2018. The following information was obtained: history, physical examination findings, physician discharge summary, antibiotic treatments, serum tests, and wound cultures. The t test was used to compare clinical and laboratory features.

RESULTS

A total of 174 patients with AD were included. Seventy patients had AD exacerbation and 104 had infectious complications, including cellulitis, abscesses, invasive infections, and eczema herpeticum. The differences between these 2 groups of patients were further verified by length of stay, serum total IgE level, and inflammatory markers (C-reactive protein and erythrocyte sedimentation rate). A total of 56 of 70 patients (80%) with AD exacerbation were treated with a systemic antibiotic. Clindamycin and vancomycin together accounted for 88% of antibiotics on admission for both groups, whereas clindamycin and sulfamethoxazole-trimethoprim were prescribed at similar rates for both groups at discharge. Wound culture results showed that the methicillin-resistant Staphylococcus aureus (MRSA) rate was significantly lower in children with AD exacerbation (22%) vs infectious complications (39%).

CONCLUSION

Children were treated with a high frequency of anti-MRSA antibiotics for inpatient AD exacerbation and infectious complications. However, the rate of MRSA was significantly lower in children with AD exacerbation. Thus, empiric antibiotic choice for infectious complications may not be appropriate for AD exacerbation.

The impact of lifestyle factors on evolution of atopic dermatitis: An alternative approach

Atopic dermatitis (AD) is a multifactorial chronic inflammatory disease with an incompletely understood etiopathogenesis. With a significant impact on the quality of life of patients, AD has attracted the interest of many research studies aiming to investigate the complex cellular and molecular mechanisms and to identify new therapeutic pathways. Various studies have focused on psycho-immunology, emphasizing the involvement of stress, defined as a general response of the body to external or internal challenges to the AD pathology. Factors like lifestyle and leisure activities may change the behavior of immune cells in AD with a strong impact on the evolution of the disease. Moreover, the poor adherence of AD patient to standard treatment approach has led to the necessity to combine different therapies in the field of complementary and alternative medicine. Although there are still not enough data to conclude that adjuvant therapies are effective in a conventional sense, there are already promising results suggesting that alternative therapeutic strategies could be a main subject of further research.

Role of Superantigens in Allergic Inflammation: Their Relationship to Allergic Rhinitis, Chronic Rhinosinusitis, Asthma, and Atopic Dermatitis

OBJECTIVES

Our intention was to review all material published to date regarding superantigens (SAgs) and allergy from an otorhinolaryngological viewpoint to understand this association more clearly.

METHODS

We identified all materials published mentioning both SAg and allergic rhinitis (AR), chronic sinusitis, asthma, and atopic dermatitis (AD) that are indexed on PubMed, Google, or the ProQuest Central databases.

RESULTS

Staphylococcus aureus is a significant bacterial pathogen in humans and has the ability to produce enterotoxins with superantigenic features. The inflammatory response in allergy seen in both B cell and T cell may be attributed to SAgs. Sufferers of both allergic asthma with rhinitis and AR alone produce serological evidence of immunoglobulin E formation to SAgs produced by S. aureus. Perennial AR sufferers carry S. aureus more frequently and the presence of the organism within the nasal cavity may exacerbate perennial AR. SAg produced by S. aureus potentially worsens the asthmatic inflammatory response within the airway and may lead to the airways becoming hyperresponsive, as well as possibly activating T cells if asthmatic control is poor. Staphylococcal SAgs potentially increase the risk of developing chronic rhinosinusitis with nasal polyposis, additionally being a marker for more severe disease. If SAgs bring about chronic inflammatory responses in the nose and sinuses, then T cells excreting interferon-gamma may be a crucial mediator. In allergic dermatitis, S. aureus could be a key player in exacerbation of the condition. Even in younger pediatric patients with allergic dermatitis, allergic hypersensitivity to SAgs is frequent and may be a factor explaining how severe the condition becomes.

CONCLUSION

Just as SAgs are known to feature in many allergic conditions, they play their part in AR, chronic rhinosinusitis, asthma, and AD. Further research is required before the relationship between SAgs and allergy can be adequately explained.

In chronic spontaneous urticaria, IgE against staphylococcal enterotoxins is common and functional

BACKGROUND

Chronic spontaneous urticaria (CSU) is a frequent disorder with recurrent itchy wheals and/or angioedema. Despite the known effectiveness of omalizumab therapy, the relevant IgE antigens are largely unknown. Recently, increased rates of elevated levels of IgE towards Staphylococcus aureus enterotoxins (SEs) were described in CSU.

AIM

To assess the prevalence and functional relevance of IgE to SEs in CSU.

METHOD

We investigated serum levels of IgE against SEs in 49 CSU patients and in 15 CSU patients additional specific IgE to SE components and basophil histamine release (BHR). Sera of 15 healthy controls (HCs) served as control group.

RESULTS

Twenty-five (51%) of the CSU patients had detectable levels of SE-IgE as compared to 5 (33%) of HCs. Specific IgE to one of the SEs, Staphylococcus enterotoxin B (SEB), was present in 5 (33%) of 15 randomly selected CSU patients vs 3 (20%) of HC. Total IgE serum levels in CSU patients were significantly correlated with SE-IgE (r = .52, P < .001) and SEB-IgE (r = .54, P = .04) serum concentrations. Interestingly, SEB-IgE levels were strongly correlated with disease activity (UASday) in CSU patients (r = .657, P = .01). Furthermore, BHR in response to SEB was significantly higher in basophils loaded with the serum of CSU patients compared to HC (P < .05) and was clinically correlated with duration of disease (r > .51, P < .05).

DISCUSSION

IgE against SEs may contribute to the pathogenesis of CSU in a subpopulation of patients. Its role and relevance in the pathophysiology of CSU need to be further analysed.

Chronic Sinusitis with Nasal Polyps: Staphylococcal Exotoxin Immunoglobulin E and Cellular Inflammation

Background

The etiology of chronic sinusitis with nasal polyposis (CS/NP) remains enigmatic. Frequently, Staphylococcus aureus is present in the nose of CS/NP patients, although the significance is unclear. Recent reports have suggested the hypothesis that these bacteria may secrete exotoxins triggering the inflammatory mucosal changes seen in CS/NP. This mechanism of immunopathology has been established in other diseases associated with Staphylococcus colonization and exotoxin secretion such as atopic dermatitis. In atopic dermatitis, the exotoxins incite a local superantigen response in which clonal T-cell activation and massive cytokine release occur in the affected skin. Second, these exotoxins can act as traditional allergens, stimulating a typical immunoglobulin E (IgE) response in the serum, which has been correlated with disease severity. This study is designed to begin the assessment of the hypothesis that a similar mechanism takes place in CS/NP.

Methods

Serum was drawn from patients with CS/NP undergoing endoscopic sinus surgery as well as 13 atopic and nonatopic control subjects without sinusitis. IgE levels to S. aureus exotoxins A (SEA), SE exotoxins B (SEB), and toxic shock syndrome toxin 1 were measured using enzyme-linked immunosorbent assay. Tissue eosinophilia and the presence of lymphocytes on hemotoxylin and eosin-stained sections of polyps were scored by a blinded pathologist and correlated to presence of toxin IgE in the serum.

Results

Staphylococcal exotoxin (SE)-specific IgE was found in the serum of 5/10 (50%) of the patients with CS/NP. In contrast, 0/13 control patients had IgE to the exotoxins (p = 0.031). Polyp eosinophil, lymphocyte, and mononuclear cell counts were compared in IgE exotoxin-positive and -negative subjects. A trend toward increased eosinophil counts in patients with SE IgE (SE IgE+) was present, but not statistically significant.

Conclusion

These results indicate that a high percentage of CS/NP patients show a systemic IgE response to S. aureus exotoxins in comparison with controls without CS/NP. Although these results are consistent with the actions of Staphylococcus toxins in other diseases, additional work is necessary to establish a local superantigen response in the nasal mucosa of CS/NP patients. (American Journal of Rhinology 18, 273–278, 2004)