Staphylococcal toxins augment specific IgE responses by atopic patients exposed to allergen

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.

Staphylococcus aureus nasal colonization increases the risk of cedar pollinosis

Background

One‐third of the people in Japan are colonized with Staphylococcus aureus (S. aureus) and suffer from virulence factor‐mediated subclinical inflammation of the nares. We investigated whether subclinical inflammation contributed to cedar pollinosis affecting 20 million people annually.

Methods

The study participants were 814 inhabitants of the A or B prefectures. We compared the colonization rate and population structure of S. aureus, in association with the prevalence of cedar pollinosis, between participants in these two areas.

Results

A prefecture had twice the annual amount of airborne cedar pollen compared with B. The prevalence of cedar pollinosis was significantly higher in A (23.5%) than in B (13.1%) (p = 0.0004). Moreover, the prevalence of cedar pollinosis was higher in female participants (23.3%) than in male participants (14.7%) (p = 0.003). In addition, the prevalence of cedar pollinosis was higher in S. aureus carriers (24.2%) than in S. aureus noncarriers (17.9%) (p = 0.03). The isolation rate of clonal complex (CC) 508 was higher in the A group (21%) than in the B group (7%) (p = 0.015).

Conclusion

Nasal colonization of S. aureus is a major risk factor for cedar pollinosis. However, the direct mechanism of this risk is currently unknown.

The prevalence of cedar pollinosis in the research area was proportional to the amount of cedar pollen. The prevalence of cedar pollinosis was higher in S. aureus carriers (24.2%) than in S. aureus noncarriers (17.9%) (p = 0.03). The prevalence of cedar pollinosis was higher in female participants (23.3%) than in male participants (14.7%) (p = 0.003).

Staphylococcal Phage in Combination with Staphylococcus Epidermidis as a Potential Treatment for Staphylococcus Aureus-Associated Atopic Dermatitis and Suppressor of Phage-Resistant Mutants

Atopic dermatitis is accompanied by the abnormal overgrowth of Staphylococcus aureus, a common cause of skin infections and an opportunistic pathogen. Although administration of antibiotics is effective against S. aureus, the resulting reduction in healthy microbiota and the emergence of drug-resistant bacteria are of concern. We propose that phage therapy can be an effective strategy to treat atopic dermatitis without perturbing the microbiota structure. In this study, we examined whether the S. aureus phage SaGU1 could be a tool to counteract the atopic exacerbation induced by S. aureus using an atopic mouse model. Administration of SaGU1 to the back skin of mice reduced both S. aureus counts and the disease exacerbation caused by S. aureus. Furthermore, the S. aureus-mediated exacerbation of atopic dermatitis with respect to IgE plasma concentration and histopathological findings was ameliorated by the application of SaGU1. We also found that Staphylococcus epidermidis, a typical epidermal symbiont in healthy skin, significantly attenuated the emergence of SaGU1-resistant S. aureus under co-culture with S. aureus and S. epidermidis in liquid culture infection experiments. Our results suggest that phage therapy using SaGU1 could be a promising clinical treatment for atopic dermatitis.

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.

Staphylococcal Exotoxins and Nasal Polyposis: Analysis of Systemic and Local Responses

Background

Staphylococcal exotoxins have been implicated in the pathogenesis of several chronic inflammatory diseases including atopic dermatitis (AD), asthma, and, most recently, chronic rhinosinusitis with nasal polyposis (CRS/NP). In severe AD, these toxins act both as superantigens (SAg), triggering massive T-cell activation, and as conventional allergens, triggering toxin-specific immunoglobulin E (IgE) in the serum. In CRS/NP, evidence for both processes has been reported but it is unclear whether these processes are linked. The aim of this study was to correlate SAg activity as inferred by staphylococcal-specific T-cell receptor (TCR) V-β expansion in the polyp and blood of CRS/NP patients with staphylococcal-specific anti-IgE antibodies in the serum.

Methods

IgE antibodies to staphylococcal exotoxin A (SEA), staphylococcal exotoxin B (SEB), and toxic shock syndrome toxin (TSST) 1 were measured in the serum of 12 individuals with CRS/NP before functional endoscopic sinus surgery. Flow cytometry was used to analyze the SEA, SEB, and TSST-1–specific TCR V-β domains on the T cells from the polyp and blood of these patients.

Results

Serum SEA-, SEB-, and TSST-1-specific IgE antibodies were detected in 0/12 (0%), 6/12 (50.0%), and 9/12 (75%) of CRS/NP patients, respectively. Evidence of SAg effect in the polyp lymphocytes (TCR V-β expansion in both CD4+ and CD8+ subsets) was noted in 7/12 (58.3%) patients. Five of 6 CRS/NP patients had overlapping evidence of a systemic IgE response and TCR V-β expansion, suggestive of exposure to the same exotoxin. No patients had evidence a SAg effect in blood lymphocytes. Nine of 12 subjects also had coexistent asthma.

Conclusion

These results provide evidence for a local SAg effect in 7/12 (58.3%) polyp patients and establish a positive correlation of V-β expansion with the presence of corresponding toxin-specific IgE in the serum.

Presence and Characterization of Sensitization to Staphylococcal Enterotoxins in Patients with Allergic Rhinitis

Exotoxins derived from Staphylococcus aureus appear to be involved in the pathogenesis of allergic diseases, especially atopic dermatitis (AD). However, little is known about sensitization to enterotoxins in cases of respiratory allergies. Because the nasal cavity is a primary site of colonization by S. aureus, we sought to determine the prevalence and role of serum immunoglobulin E (IgE) antibodies against staphylococcal enterotoxin A (SEA) and SEB in patients with allergic rhinitis (AR). The presence of SEA- and SEB-specific IgE was determined in 40 patients with AR and 16 healthy control subjects. In the rhinitis group, nasal symptom score, total serum IgE, sensitization to other inhaled allergens and the presence of sinusitis were determined. Twenty-five percent of patients with AR were sensitized to SEA/SEB whereas 6.3% of controls were sensitized to the toxins. Sensitization to SEB was predominant relative to SEA. There were no significant differences in the severity of nasal symptoms and complications of other allergic diseases including AD and bronchial asthma, between patients with or without sensitization to SEA/SEB. However, patients sensitized to these toxins were likely to show increased total serum IgE and polyvalent sensitization, suggesting that exposure and subsequent sensitization to SEA/SEB may be involved in polyvalent sensitization.

Superantigens: The Good, the Bad, and the Ugly

Increasing evidence suggests that superantigens play a role in Immune-mediated diseases. Superantigens are potent activators of CD4* T cells, causing rapid and massive proliferation of cells and cytokine production. This characteristic of superantigens can be exploited in diseases where strong immunologic responses are required, such as in the B16F10 animal model of melanoma. Superantigen administration is able to significantly enhance Ineffective anti-tumor Immune responses, resulting in potent and long-lived protective anti-tumor immunity. However, superantigens are more well-known for the role they play in diseases. Studies using an animal model for neurologic demy-elinatlng diseases such as multiple sclerosis show that superantigens can induce severe relapses and activate auto-reactive T cells not involved in the Initial bout of disease. This may also involve epitope spreading of disease. Superantigens have also been implicated in acute diseases such as food poisoning and TSS, and in chronic diseases such as psoriasis and rheumatoid arthritis. Viral superantigens are also involved in the disease process, including superantigens derived from human Immunodeficiency virus and mouse mammary tumor virus. Finally, immunotherapies that ameliorate the role played by superantigens in disease are discussed.

AllergenOnline: A peer-reviewed, curated allergen database to assess novel food proteins for potential cross-reactivity

SCOPE

Increasingly regulators are demanding evaluation of potential allergenicity of foods prior to marketing. Primary risks are the transfer of allergens or potentially cross-reactive proteins into new foods. AllergenOnline was developed in 2005 as a peer-reviewed bioinformatics platform to evaluate risks of new dietary proteins in genetically modified organisms (GMO) and novel foods.

METHODS AND RESULTS

The process used to identify suspected allergens and evaluate the evidence of allergenicity was refined between 2010 and 2015. Candidate proteins are identified from the NCBI database using keyword searches, the WHO/IUIS nomenclature database and peer reviewed publications. Criteria to classify proteins as allergens are described. Characteristics of the protein, the source and human subjects, test methods and results are evaluated by our expert panel and archived. Food, inhalant, salivary, venom, and contact allergens are included. Users access allergen sequences through links to the NCBI database and relevant references are listed online. Version 16 includes 1956 sequences from 778 taxonomic-protein groups that are accepted with evidence of allergic serum IgE-binding and/or biological activity.

CONCLUSION

AllergenOnline provides a useful peer-reviewed tool for identifying the primary potential risks of allergy for GMOs and novel foods based on criteria described by the Codex Alimentarius Commission (2003).

Pathophysiology of chronic rhinosinusitis, pharmaceutical therapy options

Research in immunology has brought great progress in knowledge of inflammatory processes in the last 2 decades, which also has an impact on the upper airways. Our understanding of the pathophysiology of chronic rhinosinusitis developed from a rather mechanistic point of view with a focus on narrow clefts and mucociliary clearance to the appreciation of a complex network of immunological pathways forming the basis of disease. We today differentiate various forms of inflammation, we start to understand complex immune-regulatory networks and the reasons for their failure, and have already developed innovative approaches for therapy for the most severely ill subjects. Due to this new knowledge in inflammation and remodeling processes within mucosal tissue, specifically on the key driving factors, new diagnostic tools and therapeutic approaches for chronic rhinosinusitis have developed; the differentiation of endotypes based on pathophysiological principles will be crucial for the use of innovative therapies, mostly humanized monoclonal antibodies. Several hundred of those antibodies are currently developed for various indications and will impact our specialty as well as pneumology to a great extent.

Molecular analysis of staphylococcal superantigens

Staphylococcal superantigens (SAgs) comprise a large family of exotoxins produced by Staphylococcus aureus strains. These exotoxins are important in a variety of serious human diseases, including menstrual and nonmenstrual toxic shock syndrome (TSS), staphylococcal pneumonia and infective endocarditis, and recently described staphylococcal purpura fulminans and extreme pyrexia syndrome. In addition, these SAg exotoxins are being increasingly recognized for their possible roles in many other human diseases, such as atopic dermatitis, Kawasaki syndrome, nasal polyposis, and certain autoimmune disorders. To clarify the full spectrum of human diseases caused by staphylococcal SAgs, it is necessary to have assays for them. At present there are 23 characterized, serologically distinct SAgs made by S. aureus: TSS toxin-1(TSST-1); staphylococcal enterotoxins (SEs) A, B (multiple variant forms exist), C (multiple minor variant forms exist), D, E, and G; and SE-like H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, and X. The most straightforward way to analyze S. aureus strains for SAgs is through polymerase chain reaction for their genes; we provide here our method for this analysis. Although it would be ideal to confirm that all of the same SAgs are produced by S. aureus strains that have the genes, antibody reagents for SAg detection are only available for TSST-1; SEs A-E and G; and enterotoxin-like proteins H, I, Q, and X. We provide a Western immunoblot procedure that allows in vitro quantification of these SAgs.

Chronic rhinosinusitis and asthma: novel understanding of the role of IgE 'above atopy'

Chronic rhinosinusitis (CRS) affects more than 10% of the European population and is often associated with asthma. Phenotypes of CRS can be differentiated based on mucosal remodelling and inflammatory patterns. Understanding the role of central mediators, such as interleukin-5, in these different phenotypes may lead to the development of specific therapeutic approaches. The impact of staphylococcal superantigens has been shown to further modify the immune response, contributing to persistent severe disease via the activation of T and B cells and the formation of local IgE. It is clear that these mechanisms are involved in the systemic spread of upper airway disease with resulting asthma comorbidity, when IgE antibodies to staphylococcal enterotoxins are present at measurable levels in serum. Recent findings point to superantigens as possible causal agents in the intrinsic form of severe asthma, and an anti-IgE strategy has shown promising therapeutic potential in nonatopic patients with nasal polyps and asthma. These findings should lead to a clinically relevant endotyping of patients with upper and lower airway disease and to a new understanding of the role of IgE 'above atopy'.

Rhinosinusitis and asthma: a link for asthma severity

The term rhinosinusitis describes an inflammation of the mucosal lining of the nose and sinuses; however, recent evidence points to the need to differentiate patients with chronic rhinosinusitis without nasal polyps from those with nasal polyps. Asthma comorbidity is especially common in nasal polyp disease and may be associated with aspirin-exacerbated respiratory disease. Of interest, asthma comorbidity is uncommon in some parts of the world but common in others. A further analysis of the inflammatory patterns also revealed that nasal polyps do not represent one single entity; interleukin (IL)-5-positive nasal polyps can be differentiated from IL-5-negative forms by different inflammatory patterns (predominance of eosinophils vs neutrophils). Staphylococcus aureus superantigens frequently colonize IL-5-positive nasal polyps and may amplify the eosinophilic inflammation, induce a polyclonal local IgE formation, and increase the risk of asthma comorbidity. Recent findings in severe asthma patients confirm the role of superantigens in lower airway disease.

Staphylococcus aureus enterotoxin B facilitates allergic sensitization in experimental asthma

BACKGROUND

Staphylococcus aureus Enterotoxin B (SEB) has immunomodulatory effects in allergic airway disease. The potential contribution of SEB to the sensitization process to allergens remains obscure.

OBJECTIVE

In order to study the effects of staphylococcal-derived toxins on the sensitization to ovalbumin (OVA) and induction of allergic airway inflammation, we have combined the nasal application of OVA with different toxins.

METHODS

Nasal applications of OVA and saline, SEA, SEB, toxic shock syndrome toxin (TSST)-1, protein A or lipopolysaccharide (LPS) were performed on alternate days from day 0 till 12. On day 14, mice were killed for the evaluation of OVA-specific IgE, cytokine production by mediastinal lymph node (MLN) cells and bronchial hyperreactivity (BHR) to inhaled metacholine. The effect of SEB on dendritic cell (DC) migration and maturation, and on T cell proliferation was evaluated.

RESULTS

Concomitant endonasal application of OVA and SEB resulted in OVA-specific IgE production, whereas this was not found with SEA, TSST-1, protein A, LPS or OVA alone. Increased DC maturation and migration to the draining lymph nodes were observed in OVA/SEB mice, as well as an increased T cell proliferation. Bronchial inflammation with an influx of eosinophils and lymphocytes was demonstrated in OVA/SEB mice, together with hyperresponsiveness and the production of IL-4, IL-5, IL-10 and IL-13 by MLN stimulated with OVA.

CONCLUSIONS

Our data demonstrate that SEB facilitates sensitization to OVA and consecutive bronchial inflammation with features of allergic asthma. This is likely due to augmentation of DC migration and maturation, as well as the allergen-specific T cell proliferation upon concomitant OVA and SEB application.

Infective dermatitis has similar immunological features to human T lymphotropic virus-type 1-associated myelopathy/tropical spastic paraparesis

Human T lymphotropic virus-type 1 (HTLV-1) is the causal agent of the HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), adult T cell leukaemia/lymphoma and infective dermatitis associated with HTLV-1 (IDH). Over-production of proinflammatory cytokines and an increase in HTLV-1 proviral load are features of HAM/TSP, but the immunological basis of IDH has not been established. In addition to severe cutaneous manifestations, the importance of IDH relies on the observation that up to 30% of children with IDH develop HAM/TSP in childhood and adolescence. In this study we determined the immune response in patients with IDH measuring interleukin (IL)-4, IL-5, IL-10, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha levels as well as the HTLV-1 proviral load. Additionally, regulatory cytokines and anti-cytokines were added to cultures to evaluate the ability of these molecules to down-modulate TNF-alpha and IFN-gamma synthesis. HTLV-1 carriers and patients with HAM/TSP served as controls. TNF-alpha and IFN-gamma levels were higher in IDH than in HTLV-1 carriers. There was no difference in IFN-gamma and TNF-alpha concentrations in IDH and HAM/TSP patients. There was a tendency for higher IL-4 mRNA expression and immunoglobulin E (IgE) levels in IDH than in HTLV-1 carriers, but the difference did not reach statistical significance. The HTLV-1 proviral load was significantly higher in IDH patients than in HTLV-1 carriers. IDH is characterized by an exaggerated Th1 immune response and high HTLV-1 proviral load. The similarities between the immunological response in patients with IDH and HAM/TSP and the high proviral load observed in IDH provide support that IDH is a risk factor for development of HAM/TSP.

Association of specific IgE to staphylococcal superantigens with the phenotype of chronic urticaria

It has been well established that bacterial superantigens lead to the induction and aggravation of chronic inflammatory skin diseases. We investigated the clinical significance of serum specific immunoglobulin E (lgE) to the staphylococcal superantigens staphylococcal enterotoxin A (SEA), staphylococcal enterotoxin B (SEB), and toxic shock syndrome toxin (TSST)-1 in patients with chronic urticaria (CU), focusing on the differences in these prevalences between aspirin-intolerant CU (AICU) and aspirin-tolerant CU (ATCU) patients. Aspirin sensitivity was confirmed by oral aspirin provocation test. There were 66 patients AICU and 117 patients ATCU in the study. Serum IgE antibodies specific for SEA, SEB, and TSST-1 were measured by the ImmunoCAP test and the patients were compared with 93 normal controls (NC). The prevalences of serum specific IgE to staphylococcal superantigens were significantly higher in CU than in NC patients (IgE to SEA, 13.7% vs. 5.4%; IgE to SEB, 12.0% vs. 4.3%; IgE to TSST-1, 18.0% vs. 6.5%; p<0.05, respectively). The patients with specific IgE to SEA, SEB, and TSST-1 had higher serum total IgE levels and higher rates of atopy. Significant associations were noted between the prevalence of specific IgE to SEA and SEB and the HLA DQB1*0609 and DRB1*1302 alleles in the AICU group. We confirmed that a sub-population of patients with CU possesses serum IgE antibodies to SEA, SEB, and TSST- 1. Particularly, the IgE immune response to TSST-1 is associated with aspirin sensitivity in CU patients.

T(H)2 adjuvants: implications for food allergy

A persistent question for immunologists studying allergic disease has been to define the characteristics of a molecule that make it allergenic. There has been substantial progress elucidating mechanisms of innate priming of T(H)2 immunity in the past several years. These accumulating data demonstrate that T(H)2 immunity is actively induced by an array of molecules, many of which were first discovered in the context of antihelminthic immune responses. Similar intrinsic or associated activities are now known to account for the T(H)2 immunogenicity of some allergens, and may prove to play a role for many more. In this review, we discuss what has been discovered regarding molecules that induce innate immune activation and the pathways that promote T(H)2-polarized immune responses generally, and specifically what role these mechanisms may play in food allergy from models of food allergy and the study of T(H)2 gastrointestinal adjuvants.

Role of staphylococcal superantigens in upper airway disease

PURPOSE OF REVIEW

Chronic rhinosinusitis with nasal polyps often represents a chronic severe inflammatory disease of the upper airways and may serve as a model for lower airway diseases such as late-onset intrinsic asthma. Enterotoxins derived from Staphylococcus aureus have been implicated in the pathophysiology of nasal polyps as disease-modifying factors; recent findings using therapeutic proof-of-concept approaches support this hypothesis.

RECENT FINDINGS

Nasal polyps (chronic rhinosinusitis with nasal polyps) are characterized by a T-helper-2 dominated cytokine pattern that includes interleukin-5 and formation of immunoglobulin E. This is in contrast to chronic rhinosinusitis without polyps, which exhibits T-helper-1 biased cytokine release. It is now evident that the cytokine environment is decisive regarding the impact of S. aureus derived enterotoxins, which function as superantigens. S. aureus enterotoxin B further shifts the cytokine pattern in nasal polyps toward T-helper-2 cytokines (increases greater than twofold for interleukin-2, interleukin-4 and interleukin-5), but it disfavours the T-regulatory cytokines interleukin-10 and transforming growth factor-beta1. Furthermore, S. aureus derived enterotoxins influence local immunoglobulin synthesis and induce polyclonal immunoglobulin E production, which may contribute to severe inflammation via activation of mast cells.

SUMMARY

From this new understanding of chronic rhinosinusitis with nasal polyps, new therapeutic approaches emerge such as anti-interleukin-5, anti-immunoglobulin E, and antibiotic treatment. These may enlarge the nonsurgical armentarium.

Functional endoscopic sinus surgery in china

The functional endoscopic sinus surgery (FESS) technique was introduced in China at the beginning of the 1980s and popularized gradually. Now its application has extended to the management of skull base lesions, orbital lesions and sinonasal tumors. This paper will review the application and relevant research of nasal endoscopic surgery and discuss its further perspectives in China.

Role of bacterial pathogens in atopic dermatitis

The skin of atopic dermatitis (AD) patients exhibits a striking susceptibility to colonization and infection with Staphylococcus aureus. This review summarizes our understanding about the role of S. aureus in AD. Indeed, S. aureus colonization is both a cause and a consequence of allergic skin inflammation. The mechanisms that allergic skin inflammation of AD promotes the increase of S. aureus colonization include skin barrier dysfunction, increased synthesis of the extracellular matrix adhesins for S. aureus, and defective innate immune responses due to decreased production of endogenous antimicrobial peptides. On the other hand, the exotoxins secreted by S. aureus are superantigens. Staphylococcal superantigens (SsAgs) may penetrate the skin barrier and contribute to the persistence and exacerbation of allergic skin inflammation in AD through the stimulation of massive T cells, the role of allergens, direct stimulation of antigen-presenting cells and keratinocytes, the expansion of skin-homing cutaneous lymphocyte-associated antigen-positive T cells, and the augmentation of allergen-induced skin inflammation. SsAgs also induce corticosteroid resistance. In therapeutic interventions, anti-inflammatory therapy alone is very effective in reducing S. aureus colonization on the skin, but antibiotic treatment alone is unable to improve the allergic skin inflammation of AD. Therefore, we recommend the combination therapy of anti-inflammatory drugs and antibiotics in the AD patients with secondary bacterial infection, exacerbated AD, or poorly controlled AD. However, when AD is well controlled by anti-inflammatory drugs alone, we do not recommend the antibiotic therapy.

Staphylococcus aureus skin colonization in atopic dermatitis children is associated with decreased IFN-gamma production by peripheral blood CD4+ and CD8+ T cells

Atopic dermatitis (AD) is a chronic inflammatory skin disorder, which is associated with an increased expression of Th2 cytokines with concomitant decrease in IFN-gamma production by circulating CD4+ and CD8+ T cells. The skin of patients with AD is often colonized by Staphylococcus aureus, which may reflect in changes in immunological parameters. The aim of the study was flow cytometric measurement of some peripheral blood lymphocyte subsets expressing naive/memory marker (RA/RO) and activation marker (CD25) as well as intracellular production of IFN-gamma by peripheral blood CD4+ and CD8+ T cells from varied severity AD children and determine the impact of S. aureus skin colonization on cytokines profiles. There was a significant increase in the percentage of CD4+ and CD8+ T cells producing IL-4 and IL-13 and decrease in the percentage of CD4+ and CD8+ T cells producing IFN-gamma upon in vitro stimulation with phorbol 12-myristate 13-acetate and ionomycin in children with AD compared to healthy ones. The absolute number of CD4+ and CD8+ T cells expressing memory marker CD45RO was elevated as compared with controls. The severity of AD was positively correlated with the percentage of lymphocyte subsets: CD45RO+, CD4+CD45RO+, and the percentage of CD3+ and CD4+ expressing CD25 as well as the number of S. aureus on the skin. In conclusion, both CD4+ and CD8+ memory T cells are involved in the immunopathogenesis of AD. S. aureus skin colonization is related with disease severity and changes in expression of CD45RO and CD25 on T cells. A decrease in the percentage of CD4+ and CD8+ T cells producing IFN-gamma in AD children may explain propensity for skin infection.

Molecular analysis of staphylococcal superantigens

Staphylococcal superantigens (SAgs) comprise a large family of exotoxins produced by Staphylococcus aureus strains. These exotoxins are important in a variety of serious human diseases, including menstrual and nonmenstrual toxic shock syndrome (TSS), staphylococcal pneumonias, and a recently described staphylococcal purpura fulminans. In addition, these SAg exotoxins are being increasingly recognized for their possible roles in many other human diseases, such as atopic dermatitis, Kawasaki syndrome, nasal polyposis, and certain autoimmune disorders. To clarify the full spectrum of human diseases caused by staphylococcal SAgs, it is necessary to have assays for them. At present there are 17 well-characterized, serologically distinct SAgs made by S. aureus: TSS toxin-1; staphylococcal enterotoxins (SEs) A, B, C (multiple minor variant forms exist), D, E, and I; and SE-like G, H, J, K, L, M, N, O, P, and Q. In addition, SE-like proteins R, S, T, and U have been identified but remain poorly characterized. The most straightforward way to analyze S. aureus strains for the well-characterized SAgs is through polymerase chain reaction for their genes; we provide here our method for this analysis. Although it would be ideal to confirm that all of the same SAgs are produced by S. aureus strains that have the genes, antibody reagents for SAg detection are only available for TSS toxin-1; SEs A-E; and enterotoxin-like proteins G, H, and Q. We provide a Western immunoblot procedure that allows in vitro quantification of these SAgs.

Aggravation of bronchial eosinophilia in mice by nasal and bronchial exposure to Staphylococcus aureus enterotoxin B

BACKGROUND

The role of bacterial enterotoxins like Staphylococcus aureus enterotoxin B (SEB) in allergic asthma remains unknown. We used a mouse model of airway allergy to study the effects of nasal or bronchial contact with SEB on bronchial allergic inflammation.

METHODS

The features of allergic asthma were induced in ovalbumin (OVA)-sensitized mice (days 1-13) by repeated exposures to nebulized OVA (days 33-37). Nasal or bronchial application of SEB was performed on three occasions (days 33-35-37), and the effects on bronchial inflammation, IgE titres and expression levels of mRNA for T helper type 2 cytokines and other inflammatory mediators were evaluated.

RESULTS

Both nasal and bronchial SEB enhanced the allergen-induced bronchial inflammation, as reflected by more eosinophilic inflammation in the airway lumen and in bronchial tissue. Aggravation of experimental asthma correlated with higher expression of mRNA for IL-5, IL-4, IFN-gamma, IL-12 p40, eotaxin-1 and TGF-beta in bronchi. In addition, nasal SEB elevated concentrations of IL-4, IL-5 and IFN-gamma in serum and bronchial SEB increased titres of OVA-specific and total IgE in serum.

CONCLUSION

Our data illustrate the potential of both nasal as well as bronchial SEB to aggravate several features of allergic asthma in a mouse model.

Atopic dermatitis

Atopic dermatitis is an especially common and frustrating condition, and the prevalence is increasing. The disease can adversely affect the quality of life of patients and caregivers. Significant advances in our understanding of the pathogenesis have led to improvements in therapy. Patient and caregiver education, avoidance of potential triggering factors, optimal skin care, and pharmacotherapy offer the potential for good control for most patients.

Immune responses to Staphylococcus aureus and Psoroptes ovis in sheep infected with P. ovis — the sheep scab mite

In sheep, lesions caused by Psoroptes ovis, the sheep scab mite, may become colonized by Staphylococcus aureus. The present study compares clinical signs, lesional area and the immune response to P. ovis and S. aureus in P. ovis-infested sheep with and without secondary S. aureus infection. No differences were detected in the clinical signs or lesional areas in the S. aureus-positive and -negative sheep. However, 6 weeks after infestation an IgG but not IgE isotype antibody response to S. aureus was detected in the S. aureus-positive but not the S. aureus-negative group of sheep. This response targeted S. aureus antigens with molecular weights of approximately 36, 38, 50 and 65 kDa. In addition, 6 weeks after infestation an IgE response to P. ovis was detected in the S. aureus-positive but not the S. aureus-negative group of sheep.

Factors responsible for differences between asymptomatic subjects and patients presenting an IgE sensitization to allergens. A GA2LEN project

The synthesis of allergen-specific IgE is required for the development of allergic diseases including allergic rhinitis and allergic asthma (patients), but many individuals with allergen-specific IgE do not develop symptoms (asymptomatic subjects). Differences may exist between asymptomatic subjects and patients. Whether the presence of allergen-specific IgE translates into clinical allergy most likely depends on a complex interplay of multiple factors. These include a family history of atopy, the levels of total serum IgE and, allergen-specific IgE or IgG, epitope-specificity of IgE and their degree of polyclonality (mono- vs polysensitized), as yet unidentified serum factors, the balance of T regulatory cells (Treg) and Th1/Th2 cells, the polymorphisms of the high affinity receptor for IgE (FcepsilonRI) and other factors regulating the activation of FcepsilonRI-bearing cells. Asymptomatic subjects may be more often monosensitized than patients who may be more often polysensitized. There are many unanswered important questions that need to be addressed in order to better understand how IgE sensitization translates into clinical allergy. The assessment of differences between the asymptomatic and symptomatic groups of subjects represent one of the scientific programs of Global Allergy and Asthma European Network funded by the European Union and the hypotheses underlying these differences are presented in this paper.

Chronic rhinosinusitis and superantigens

This article discusses the potential role of bacterial superantigens (SAgs) in chronic rhinosinusitis with nasal polyposis (CRS/NP). First, it briefly describes SAgs, focusing on how they interact with the immune system by binding to T-cell receptors (TCR) and major histocompatibility complex (MHC) class II molecules. Second, it discusses the role of SAgs in other chronic inflammatory diseases.Finally, it presents evidence for the role of SAgs in the pathogenesis and maintenance of CRS/NP focusing on current research and future considerations.

Nasal carriage of Staphylococcus aureus in house dust mite allergic patients and healthy controls

BACKGROUND

Staphylococcal colonization may influence the course of allergic diseases such as atopic dermatitis or allergic rhinitis. The frequency of Staphylococcus aureus (SA) nasal carriage and its possible influence on persistent allergic rhinitis was investigated.

METHODS

In nasal lavages from 22 patients with house dust mite allergy and 18 healthy controls, the number of SA colony forming units per ml were assessed and related to nasal symptom scores, the concentrations of three inflammatory cell activation markers, nasal total IgE and 17 cytokines in nasal secretions.

RESULTS

SA was found in 15/22 allergic patients and 4/18 controls (P < 0.01). Comparing allergic SA carriers with allergic noncarriers, nasal symptom scores tended to be higher (P < 0.1), and the cell activation markers ECP (10(2.23+/-0.33)vs 10(1.45+/-0.50) ng/ml; P < 0.05) and elastase (10(2.70+/-0.21)vs 10(2.12+/-0.34) ng/ml; P < 0.01), and nasal total IgE-levels (10(1.66+/-0.38)vs 10(1.2+/-0.28) kU/ml; P < 0.05) were significantly higher in allergic SA carriers. Nasal SA carriers had a higher nasal IL-13/IFN-gamma ratio (P < 0.01), and this was correlated with higher nasal total IgE in allergic patients (r = 0.6, P < 0.05).

CONCLUSION

Nasal SA carriage is frequent in patients with persistent allergic rhinitis. The data of this study suggest that they are not only secondary bystanders, but actively modulate the disease by promoting local IgE production.

Increased levels of serum-specific immunoglobulin e to staphylococcal enterotoxin a and B in patients with allergic rhinitis and bronchial asthma

BACKGROUND

The association between staphylococcal enterotoxins and atopic dermatitis (AD) is well characterized. We aim to evaluate the association between sensitization to staphylococcal enterotoxin A (SEA) and/or B (SEB) and the development of allergic airway disease.

METHODS

Two hundred and seventy-four patients were grouped into allergic rhinitis (AR) and/or bronchial asthma (BA) only, AD only and AR/BA+AD. The AR/BA only group was further divided into AR only, AR and airway hyperresponsiveness (AR+AHR) and BA. The allergen-specific and total immunoglobulin E (IgE) antibodies were determined by the CAP system. The associations of sensitization to SEA/SEB with allergic airway disease were analyzed by logistic regression analysis.

RESULTS

The overall rate of sensitization to SEA/SEB was 25.7%, whereas the rate of the AD only group (45.5%) was significantly higher than that of the AR/BA only group (24.5%, chi2=8.1). After sensitization to SEA/SEB, the geometric mean total IgE levels were significantly elevated in patients with AR+AHR and BA, but not in those with AR only. BA patients had higher geometric mean values of SEA- and SEB-specific IgE than AR only and AR+AHR patients. Logistic regression revealed that AR/BA only was more associated with sensitization to SEA/SEB (odds ratio 6.57) than AD only and AR/BA+AD (odds ratio 2.44 and 1.72).

CONCLUSIONS

Atopic status after sensitization to SEA/SEB was more closely associated with BA than with other airway allergy, implying that SEA/SEB may play a role in exacerbating airway allergy and increasing the risk of allergic airway disease. Our study suggests that staphylococcal enterotoxins play a prominent role in the pathogenesis of allergic airway disease as well as AD.

Atopic dermatitis: beyond the itch that rashes

The prevalence of atopic dermatitis is increasing, and more than 50% of children with atopic dermatitis go on to develop asthma and allergies. A better understanding of the underlying immune abnormalities of this complex chronic relapsing skin disease is needed. Although the optimal treatment approach remains to be defined, several recent studies suggest a rationale for using topical calcineurin inhibitors as early intervention and adding topical corticosteroids as rescue therapy if needed.

A clinician's paradigm in the treatment of atopic dermatitis

Successful management of atopic dermatitis requires a multipronged approach that includes skin barrier function care, use of topical or systemic agents, and identification and elimination of precipitating or exacerbating factors. Because the origin of atopic dermatitis is multifactorial and trigger factors differ among patients, treatment plans must be specific to the individual patient. This article offers an example of a permutational, or flexible, treatment paradigm. The approach utilizes 4 topical regimens--high-potency topical corticosteroids, lowest effective potency topical corticosteroids, topical calcineurin inhibitors (TCIs), or topical corticosteroid/TCI combinations--as initial therapy in a variety of induction protocols, as determined by the severity of a patient's condition and history. The paradigm permits treatment to progress from a chosen induction therapy to maintenance therapy. During the patient's induction therapy, as soon as an acceptable level of clearance is achieved, therapy should be adjusted to a maintenance regimen, such as monotherapy with either a TCI or a lowest effective potency topical corticosteroid (the latter used intermittently) or an alternation of the two agents. If there is no clearance or positive response with the initial induction protocol, the clinician should move to one of the alternative regimens.

Nasal exposure to Staphylococcal enterotoxin enhances the development of allergic rhinitis in mice

BACKGROUND

Staphylococcal enterotoxins (SEs) appear to play a role in the pathogenesis of allergic disease. However, little is known whether the nasal exposure to SE affects the development of allergic rhinitis (AR).

OBJECTIVE

We sought to determine the in vivo effect of nasal exposure to SE on the development of AR using mouse model.

METHODS

BALB/c mice were intranasally sensitized with Schistosoma mansoni egg antigen (SmEA) in the presence or absence of staphylococcal enterotoxin B (SEB). Control mice were intranasally sensitized with either SEB or SmEA alone. The production of antigen-specific antibodies including IgE, nasal eosinoplilia and cytokines by nasal mononuclear cells was compared among mice that had or had not received SEB treatment.

RESULTS

Nasal exposure to SEB enhanced the development of AR in SmEA-sensitized mice, as manifested by SmEA-specific IgE production, nasal eosinophilia, and IL-4 and IL-5 production by nasal mononuclear cells after Ag challenge. This treatment also elicited IFN-gamma production by SmEA-primed cells. In addition, these mice produced SEB-specific IgE whereas mice treated with SEB without SmEA sensitization did not produce SEB-specific IgE or demonstrate nasal eosinophilia.

CONCLUSION

These results suggest that the nasal exposure to SEB enhances susceptibility to AR although the exposure to SE solely does not induce AR.

Bactericidal activity of flucloxacillin against Staphylococcus aureus in primary keratinocyte cultures of lesional and unaffected skin of patients suffering from atopic dermatitis

More than 90% of patients with atopic dermatitis (AD) are colonized by Staphylococcus aureus. Due to prevalent multi-resistant strains, it is highly difficult to eliminate S. aureus contamination of primary cell cultures of human AD skin by means of the antibiotics commonly used in cell culture. Therefore, an anti-staphylococcal treatment was investigated by which sterile proliferating keratinocyte cultures are attained from lesional and unaffected skin of AD patients by applying flucloxacillin, which in general is systemically used in vivo. The treatment with 1% flucloxacillin for 20 min included both colonized skin samples and contaminated primary cell cultures. In the case of persistent contamination, this step was repeated as often as required until complete decontamination without any cytotoxic indications was achieved. Antibacterial treatment with flucloxacillin permitted the cultivation of sterile, vital, and proliferating primary cultures of human skin keratinocytes from lesional and unaffected skin of AD patients with S. aureus colonization. The method increased the success rate of isolation of AD keratinocytes from 30 to 90%, representing on average 3 vs. 9 successfully isolated, sterile and proliferating cultures out of 10 contaminated skin biopsies, which is comparable to normal human keratinocyte isolation rates.

Organization of secondary lymphoid tissue and local IgE formation to Staphylococcus aureus enterotoxins in nasal polyp tissue

BACKGROUND

Bilateral nasal polyposis (NP) is characterized by high concentrations of IgE in NP tissue, which show no relation to the atopic status. We aimed to study the relationship between systemic and local IgE formation, nasal carriage of Staphylococcus aureus and nasal polyposis.

METHODS

In serum and nasal tissue homogenates from 24 NP patients and 12 controls, we determined concentrations of total IgE and IgE antibodies to inhalant allergens and S. aureus enterotoxins (SAEs; A,B,C,D,E,TSST) by ImmunoCAP. Tissue cryosections were stained for CD3, CD20, CD38, CD23, FcepsilonRI, IgE and SEA/SEB.

RESULTS

We demonstrated a higher incidence of S. aureus colonization (17/24) and IgE antibodies to SAEs in NP tissue (12/24) compared with controls (3/12 and 0/12, respectively). Total IgE and IgE antibodies in serum and NP tissue were dissociated because of local polyclonal IgE formation in NP tissue. Staining of NP tissue revealed follicular structures characterized by B and T cells, and lymphoid accumulations with diffuse plasma cell infiltration.

CONCLUSIONS

We demonstrated the organization of secondary lymphoid tissue in polyp tissue and a polyclonal hyper-immunoglobulinemia E associated with the presence of IgE antibodies to SAEs, colonization with S. aureus, and tissue eosinophilia in a relevant subgroup of polyp patients.

Rhinosinusitis: establishing definitions for clinical research and patient care

Background

There is a need for more research on all forms of rhinosinusitis. Progress in this area has been hampered by a lack of consensus definitions and the limited number of published clinical trials.

Objectives

To develop consensus definitions for rhinosinusitis and outline strategies useful in clinical trials.

Methods

Five national societies, The American Academy of Allergy, Asthma and Immunology; The American Academy of Otolaryngic Allergy; The American Academy of Otolaryngology Head and Neck Surgery; The American College of Allergy, Asthma and Immunology; and the American Rhinologic Society formed an expert panel from multiple disciplines. Over two days, the panel developed definitions for rhinosinusitis and outlined strategies for design of clinical trials.

Results

Committee members agreed to adopt the term “rhinosinusitis” and reached consensus on definitions and strategies for clinical research on acute presumed bacterial rhinosinusitis, chronic rhinosinusitis without polyposis, chronic rhinosinusitis with polyposis, and classic allergic fungal rhinosinusitis. Symptom and objective criteria, measures for monitoring research progress, and use of symptom scoring tools, quality-of-life instruments, radiologic studies, and rhinoscopic assessment were outlined for each condition.

Conclusion

The recommendations from this conference should improve accuracy of clinical diagnosis and serve as a starting point for design of rhinosinusitis clinical trials.

Rhinosinusitis: Establishing definitions for clinical research and patient care

Background

There is a need for more research on all forms of rhinosinusitis. Progress in this area has been hampered by a lack of consensus definitions and the limited number of published clinical trials.

Objectives

To develop consensus definitions for rhinosinusitis and outline strategies useful in clinical trials.

Study design

Five national societies, The American Academy of Allergy, Asthma and Immunology; The American Academy of Otolaryngic Allergy; The American Academy of Otolaryngology Head and Neck Surgery; The American College of Allergy, Asthma and Immunology; and the American Rhinologic Society formed an expert panel from multiple disciplines. Over two days, the panel developed definitions for rhinosinusitis and outlined strategies for design of clinical trials.

Results

Committee members agreed to adopt the term “rhinosinusitis” and reached consensus on definitions and strategies for clinical research on acute presumed bacterial rhinosinusitis, chronic rhinosinusitis without polyposis, chronic rhinosinusitis with polyposis, and classic allergic fungal rhinosinusitis. Symptom and objective criteria, measures for monitoring research progress, and use of symptom scoring tools, quality-of-life instruments, radiologic studies, and rhinoscopic assessment were outlined for each condition.

Conclusions

The recommendations from this conference should improve accuracy of clinical diagnosis and serve as a starting point for design of rhinosinusitis clinical trials.

Increased IgE-antibodies to Staphylococcus aureus enterotoxins in patients with COPD

Recent evidence suggests that Staphylococcus aureus enterotoxins (SAEs) could modify airway disease by acting as superantigens, an immune response that can be monitored by detection of IgE antibodies to SAEs. We studied the expression of total IgE and specific IgE to SAEs using the Uni-CAP system in healthy controls, smokers without COPD and COPD patients. Only 1/10 controls (10%) and 1/16 smokers (6.3%) had IgE to SAEs compared to 7/18 patients with stable COPD (38.9%) and 21/54 patients with exacerbated COPD (38.9%). The IgE levels to SAEs of the patients with stable COPD (0.18 [0.05-26.2]kUA/l) and the patients with exacerbated COPD (0.09 [0.05-18.6]kUA/l) were significantly higher than those of smokers (n = 16; 0.05 [0.05-0.82]kUA/l) and controls (n = 11; 0.05 [0.05 0.9]kUA/l, P<0.05). IgE to SAEs decreased significantly in the exacerbated patients during hospitalization (0.13 [0.05-18.3] vs. 0.05 [0.05-11]kUA/l, P<0.001) going along with a significant increase in FEV1 (38.1 [16.9-79.5] vs. 51.6 [15-80]%predicted, P<0.001). Similarly to severe asthma, we found significantly elevated IgE to SAE in COPD patients. Our data for the first time suggest differences between healthy subjects, smokers and patients with established COPD regarding the role of bacterial products and point to a possible disease modifying role of SAEs.

Canine atopic dermatitis: new targets, new therapies

Atopic dermatitis is a common allergic skin disease of complex etiopathogenesis in both humans and dogs. Immediate-type hypersensitivity to environmental allergens that arises as a result of environmental and genetic factors is a major part of the pathogenesis in most but not all patients. Alterations in epidermal barrier function, priming of cutaneous antigen-presenting cells with IgE, intrinsic keratinocyte defects, and even development of autoimmunity are also factors that contribute to the primary disease. Secondary factors, especially infections with Staphylococcus and yeast organisms, strongly influence the course of this skin disease. The relatively recent understanding of the complexities of atopic dermatitis has resulted in changes in diagnostic and therapeutic strategies for the disease. We now know that the best therapeutic approach is to use combinations of multiple modalities individualized for each patient over the course of his or her lifetime.

Superantigens and nasal polyps

Nasal polyps represent an often severe T-cell-orchestrated eosinophilic upper airway disease with currently unknown pathogenesis, often associated with lower airway disease, such as asthma. Superantigens, predominantly derived from Staphylococcus aureus, are potent activators of T cells, induce the synthesis of IgE in B cells, and have direct effects on pro-inflammatory cells, such as eosinophils. IgE antibodies to S. aureus enterotoxins have been described in polyp tissue, linked to a local polyclonal IgE production and an aggravation of eosinophilic inflammation. Furthermore, such IgE antibodies have also been described in the sera of patients with asthma, and linked to severity of disease and steroid insensitivity. This review summarizes our current understanding of the possible role of S. aureus enterotoxins in chronic severe airway disease, such as nasal polyposis.

High prevalence of superantigens associated with the egc locus in Staphylococcus aureus isolates from patients with atopic eczema

The present study was aimed at identifying a possible correlation between disease severity and colonization with superantigen-producing Staphylococcus aureus strains in patients with atopic eczema. To this end, Staphylococcus aureus strains from 91 patients with atopic eczema were screened for various staphylococcal superantigens such as SEA, SEB, SEC, SED, TSST1, the recently described enterotoxin gene cluster egc (which encodes the enterotoxins SEG, SEI, SEK, SEM, and SEO), and the see, seh, and sej loci. Swabs were taken from seven different sites in each patient. The rate of colonization with Staphylococcus aureus was 87.9%. Of those patients colonized, 35% were colonized with more than one different strain. Of the 120 genetically different strains investigated, the egc locus was found in 48.3% and the sej locus in 7.5%. The see and seh loci were not found in any strain. The presence of the classical superantigens SEA-SED or TSST1 was found in 38.3%. Overall, 71.3% of the Staphylococcus aureus-positive patients harbored at least one superantigen-producing strain on their skin. There was no difference in the prevalence of superantigens between atopic eczema patients and healthy volunteers. Moreover, there was no difference in the extent of disease expression between patients colonized by superantigen-positive Staphylococcus aureus strains and those with superantigen-negative strains as measured by the SCORAD system. However, patients colonized with Staphylococcus aureus had a significantly higher SCORAD score than those not colonized.

Tacrolimus ointment for the management of atopic dermatitis

The management of atopic dermatitis is set for a major shift with the introduction of the first new topical treatment for the condition in 40 years--the non-steroidal topical immunomodulator tacrolimus (Protopic). Backed by strong clinical data, tacrolimus ointment is a valuable addition to topical steroids in the management of moderate-to-severe atopic dermatitis.