Role of staphylococcal superantigens in upper airway disease

Staphylococcal enterotoxin specific IgE and asthma: a systematic review and meta-analysis

BACKGROUND

Recent literature suggests that Staphylococcal enterotoxin specific IgE may be a risk factor for asthma.

OBJECTIVE

To investigate the associations between Staphylococcal enterotoxin sensitization and asthma.

METHODS

A systematic review and meta-analysis was performed for relevant case-control or population-based studies, published in the peer-reviewed journals until February 2013. Data were extracted on study designs, subjects, definitions and the prevalence of Staphylococcal enterotoxin sensitization.

RESULTS

A total of 683 studies were initially identified, of which 7 studies finally met the inclusion criteria (5 case-control and 2 population-based studies). All the included studies reported higher prevalence of the sensitization in asthmatics than in controls, despite clinical and methodological heterogeneity. In a meta-analysis, the pooled odds ratio of the sensitization for asthma was 2.95 (95% confidence intervals 2.28-3.82).

CONCLUSION

Staphylococcal enterotoxin sensitization was significantly associated with asthma. The mechanisms of associations warrant further elucidation.

The adjuvant-like activity of staphylococcal enterotoxin B in a murine asthma model is independent of IL-1R signaling

BACKGROUND

Staphylococcal enterotoxin B (SEB) is a superantigen known to be a modulator of chronic airway inflammation in mice and humans, yet little is known about the mechanisms that regulate its interaction with the innate immune system. We investigated this mechanism in a murine model of allergic airway inflammation induced by OVA (ovalbumin) in the presence of SEB.

METHODS

Superantigen-induced allergic inflammation was studied in IL-1R knockout (KO) mice exposed to OVA+SEB. Multicolor flow cytometry was used to analyze the inflammatory cell profile in airways and lymph nodes. Production of IL-4, IL-5, IL-10, and IL-13 in lymph nodes was assessed by Luminex technology.

RESULTS

In wild-type mice, endonasal instillation of OVA+SEB induced a pulmonary inflammation, characterized by an increase in the number of eosinophils, T cells, and dendritic cells and in the production of Th2 cytokines and OVA-specific IgE. In IL-1R KO mice exposed to OVA+SEB, attraction of CD4+ cells and production of Th2 cytokines were reduced. However, knocking out IL-1R did not affect any of the features of allergic airway inflammation, such as bronchial eosinophilia, OVA-specific IgE production and goblet cell metaplasia.

CONCLUSION

We provide new insights into the mechanisms of airways allergy development in the presence of bacterial superantigen. The asthma features induced by OVA+SEB, such as bronchial eosinophilia, goblet cell proliferation, production of OVA-specific IgE and increase in inflammatory dendritic cells, are IL-1R independent. Yet, IL-1R signaling is crucial for CD4 cell accumulation and Th2 cytokine production.

Staphylococcus aureus toxins--their functions and genetics

The outcome of encounters between Staphylococcus (S.) aureus and its human host ranges from life-threatening infection through allergic reactions to symptom-free colonization. The pan-genome of this bacterial species encodes numerous toxins, known or strongly suspected to cause specific diseases or symptoms. Three toxin families are in the focus of this review, namely (i) pore-forming toxins, (ii) exfoliative toxins and (iii) superantigens. The majority of toxin-encoding genes are located on mobile genetic elements (MGEs), resulting in a pronounced heterogeneity in the endowment with toxin genes of individual S. aureus strains. Recent population genomic analysis have provided a framework for an improved understanding of the temporal and spatial scales of the motility of MGEs and their associated toxin genes. The distribution of toxin genes among clonal lineages within the species S. aureus is not random, and phylogenetic (sub-)lineages within clonal complexes feature characteristic toxin signatures. When studying pathogenesis, this lineage association, which is caused by the clonal nature of S. aureus makes it difficult to discriminate effects of specific toxins from contributions of the genetic background and/or other associated genetic factors.

Role of bacterial and fungal biofilms in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a very common condition that remains poorly understood from a pathogenic standpoint. Recent interest has been sparked by a potential role for biofilms in this process, with a significant body of evidence implicating them in inciting sinonasal inflammation. Biofilms are clearly present on the sinus mucosa of CRS patients, and their presence there is associated with severe disease characteristics and surgical recalcitrance. We are beginning to understand the importance of the species within these biofilms, but there may be other as-yet-unidentified factors at play in influencing disease outcomes. Recent exciting research has emerged documenting the immune response to the presence of biofilms-research that will ultimately solidify the nature and extent of the contribution of biofilms in CRS pathogenesis. Future research should focus on evidence-based antibiofilm treatments with reference to efficacy and timing of treatment.

A genetic effect of IL-5 receptor α polymorphism in patients with aspirin-exacerbated respiratory disease

Persistent eosinophil activation in both the upper and lower airway mucosa is a central feature of aspirin-exacerbated respiratory disease (AERD). Eosinophil activation and survival are profoundly influenced by interleukin 5 (IL-5) and its receptor, IL-5R. In patients susceptible to allergic disorders, IL-5 receptor α (IL5RA) polymorphisms have been reported; however, an association with AERD remains unclear. We hypothesize that IL5RA polymorphisms may contribute to eosinophil activation in AERD patients. We recruited 139 AERD patients, 171 aspirin-tolerant asthma patients and 160 normal controls. IL5RA polymorphisms (−5993G>A, −5567C>G and −5091G>A) were genotyped and functional activity of polymorphism was assessed by luciferase reporter assay and electrophoretic mobility shift assay (EMSA). There was no significant difference in the genotype frequency of the three polymorphisms among the three groups. AERD patients carrying the AA genotype at −5993G>A had a significantly higher presence of serum-specific immunoglobulin E (IgE) to staphylococcal enterotoxin A (P=0.008) than those with the GG/GA genotype. In vitro, the −5993A allele had a higher promoter activity compared with the −5993G allele in human mast cell (HMC-1; P=0.030) and human promyelocytic leukemia (HL-60; P=0.013) cells. In EMSA, a −5993A probe produced a specific shifted band than the −5993G had. These findings suggest that a functional polymorphism in IL5RA may contribute to eosinophil and mast cell activation along with specific IgE responses to staphylococcal enterotoxin A in AERD patients.

Airway exposure to staphylococcal enterotoxin A potentiates allergen-induced bone marrow eosinophilia and trafficking to peripheral blood and airways

Bone marrow (BM) eosinopoiesis is a common feature during allergen exposure in atopic individuals. Airway exposure to staphylococcal superantigens aggravates allergic airway disease and increases the output of BM eosinophils. However, the exact mechanisms regulating eosinophil mobilization and trafficking to the peripheral circulation and airways remain to be elucidated. Therefore, this study aimed to investigate the mechanisms determining the BM eosinopoiesis in allergic mice under exposure to staphylococcal enterotoxin A (SEA). Ovalbumin (OVA)-sensitized male BALB/C mice were intranasally exposed to SEA (1 μg), and at 4, 12, 24, and 48 h later animals were challenged with OVA (10 μg, twice a day). Measurement of IL-5, eotaxin, and granulocyte-macrophage colony-stimulating factor (GM-CSF) levels, flow cytometry for CCR3(+), VLA4(+), and CCR3(+)VLA4(+), as well as adhesion assays to VCAM-1 were performed in BM. Prior airway exposure to SEA time dependently increased the BM eosinophil number in OVA-challenged mice. Eosinophils gradually disappear from peripheral blood, being recruited over time to the airways, where they achieve a maximal infiltration at 24 h. SEA exposure increased the levels of IL-5 and eotaxin (but not GM-CSF) in BM of OVA-challenged mice. Marked increases in CCR3(+) and CCR3(+)VLA4(+) expressions in BM eosinophils of OVA-challenged mice were observed, an effect largely reduced by prior exposure to SEA. Adhesion of BM eosinophils to VCAM-1 was increased in OVA-challenged mice, but prior SEA exposure abrogated this enhanced cell adhesion. Accumulation of BM eosinophils by airway SEA exposure takes place through IL-5- and CCR3-dependent mechanisms, along with downregulation of CCR3/VL4 and impaired cell adhesion to VCAM-1.

Nontuberculous Mycobacteria in household plumbing as possible cause of chronic rhinosinusitis

Millions of Americans live with chronic sinus infection. Most infections are caused by either bacteria or fungi. Some of these infections can be hard to treat, eluding medical and surgical treatment and persisting for months or even years. A recent study in New York found that some patients with a chronic sinus infection had tuberculosis-like organisms (mycobacteria) in their sinuses and that the same organisms were also in the tap water at their homes. These mycobacteria can be resistant to commonly used antimicrobial drugs. Doctors should check for mycobacteria in patients with treatment-resistant sinus infection. Patients who flush their sinuses at home should use sterile saline, not tap water.

Symptoms of chronic rhinosinusitis (CRS) often persist despite treatment. Because nontuberculous mycobacteria (NTM) are resistant to commonly used antimicrobial drugs and are found in drinking water that patients may use for sinus irrigation, we investigated whether some CRS patients were infected with NTM in New York, New York, USA, during 2001–2011. Two approaches were chosen: 1) records of NTM-infected CRS patients were reviewed to identify common features of infection and Mycobacterium species; 2) samples from plumbing in households of 8 NTM-infected patients were cultured for NTM presence. In 3 households sampled, M. avium sharing rep-PCR and pulsed field gel electrophoresis fingerprints identified M. avium isolates clonally related to the patients’ isolates. We conclude that patients with treatment-resistant CRS may be infected with NTM and should have cultures performed for NTM so appropriate therapy can be instituted. In addition, the results suggest that CRS patients can be infected by NTM in their household plumbing.

Local receptor revision and class switching to IgE in chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (NP) and allergic rhinitis (AR) is characterized by local Th2 inflammation and up-regulation of IgE; however, IgE in NP is 'polyclonal' and allergen specific, whereas IgE in AR is 'oligoclonal' and allergen specific. Germinal center (GC) reactions occur in AR, while only the formation of GC-like structures in NP is described. The aim of this study was to investigate the involvement of local IgE production, class switch recombination, and receptor revision in NP.

METHODS

We compared the levels of local IgE, germline gene transcripts, and mature Ig mRNA expression, recombination activating gene (RAG1 and RAG2), key markers of Th2 inflammation, and GC reactions in NP tissue vs AR and control tissue. Nasal mucosa was immunostained for the co-expression of RAG1 and RAG2 in B cells, plasma cells, and T cells, using dual or triple immunofluorescence (IF).

RESULTS

In NP, local IgE level and key markers of local class switching are increased compared with AR and normal controls (NC). In NP, switch circle transcripts reveal ongoing local class switch recombination to IgE. Up to 30% of B cells, plasma cells, and T cells in nasal polyps re-express both RAG1 and RAG2, required for receptor revision. RAG1 and RAG2 mRNA concentrations are increased in NP and correlated with the magnitude of inflammation and the presence of S. aureus enterotoxin (superantigen)-specific IgE in the nasal polyp mucosa.

CONCLUSION

Our results provide the first evidence of local receptor revision and class switching to IgE, and B-cell differentiation into IgE-secreting plasma cells in NP.

Expression of dual oxidases and secreted cytokines in chronic rhinosinusitis

BACKGROUND

The airway epithelium generates reactive oxygen species (ROS) as a first line of defense. Dual oxidases (DUOX1 and DUOX2) are the H2 O2 -producing isoforms of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family in the airway epithelium. The purpose of this study was to explore the molecular expression, function, and regulation of DUOXs in chronic rhinosinusitis (CRS).

METHODS

Human nasal tissue samples and nasal secretions were collected from 3 groups of patients undergoing sinus surgery (normal, n = 7; CRS with polyposis [CRSwP], n = 6; CRS without polyposis [CRSsP], n = 6). Nasal secretions were studied for cytokine and H2 O2 content. Tissue samples were used to determine DUOX mRNA and protein expression.

RESULTS

DUOX1 mRNA level (80.7 ± 60.5) was significantly increased in CRSwP compared to normal (2.7 ± 1.2) and CRSsP (2.3 ± 0.5, p = 0.042). DUOX2 mRNA levels were increased in both CRSwP (18.6 ± 9.9) and CRSsP (4.0 ± 1.3) compared to normal (1.1 ± 0.3; p = 0.008). DUOX protein was found in the apical portion of the nasal epithelium and protein expression was increased in CRSwP and CRSsP. H2 O2 production was significantly higher in CRSwP (160.9 ± 59.4 nM) and CRSsP (81.7 ± 5.6 nM) compared to normal (53.5 ± 11.5 nM, p = 0.032). H2 O2 content of nasal secretions correlated tightly with DUOX expression (p < 0.001). Cytokines (eotaxin, monokine-induced by interferon γ [MIG], tumor necrosis factor [TNF]-α, interleukin [IL]-8) showed significantly higher levels in nasal secretions from CRSwP compared to normal (p < 0.05). Levels of eotaxin, MIG, and TNF-α correlated closely with DUOX expression.

CONCLUSION

DUOX1 and DUOX2 were identified as factors upregulated in CRS. Close correlations between DUOX expression and H2 O2 release, and correlation between key inflammatory cytokines and DUOX expression, indicate DUOX in the inflammatory response in CRS.

Topical steroids for nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) represents inflammatory changes throughout the nose and sinuses from a group of disorders which all lead to swelling and overgrowth of the nasal mucosa. Topical corticosteroids have been the most widely used treatment, with each clinician using different regimes, at different doses, in different settings and with or without sinus surgery. CRSwNP requires ongoing medical management to prevent recurrence.

OBJECTIVES

To assess the effects of topical corticosteroids on CRSwNP and to analyse various subgroups, including patients who had sinus surgery immediately prior to the delivery of the corticosteroids, surgery any time prior to the topical corticosteroids or patients who had never had previous surgery. Also to assess the most effective dose and delivery methods for topical corticosteroids.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the search was 10 April 2012.

SELECTION CRITERIA

Randomised controlled trials studying topical corticosteroids for patients with CRSwNP.

DATA COLLECTION AND ANALYSIS

At least two authors reviewed the search results and selected trials meeting the eligibility criteria, obtaining full texts and contacting authors. We documented our justification for the exclusion of studies. At least two authors extracted data using a pre-determined, standardised data form.

MAIN RESULTS

Forty studies (3624 patients) met the inclusion criteria. The trials were at low (21 trials), medium (13 trials) and high (six trials) risk of bias. The primary outcomes were sino-nasal symptoms, polyp size and polyp recurrence after surgery. When compared to placebo, topical corticosteroids improved overall symptom scores (standardised mean difference (SMD) -0.46; 95% confidence interval (CI) -0.65 to -0.27, P < 0.00001; seven trials, n = 445) and had a higher proportion of patients whose symptoms improved (responders) (risk ratio (RR) 1.71; 95% CI 1.29 to 2.26, P = 0.0002; four trials, n = 234). Topical corticosteroids also decreased the polyp score (SMD -0.73; 95% CI -1.00 to -0.46, P < 0.00001; three trials, n = 237) and had a greater proportion of patients with a reduction in polyp size (responders) (RR 2.09; 95% CI 1.65 to 2.64, P < 0.00001; eight trials, n = 785) when compared to placebo. Topical corticosteroids also prevented polyp recurrence after surgery (RR 0.59; 95% CI 0.45 to 0.79, P = 0.0004; six trials, n = 437). Subgroup analyses by sinus surgery status revealed a greater benefit in reduction of polyp score when topical steroid was administered any time after sinus surgery (SMD -1.19; 95% CI -1.54 to -0.83) compared to patients who had never had surgery (SMD -0.13; 95% CI -0.53 to 0.28, P < 0.00001). There was no difference between groups in terms of adverse events.

AUTHORS' CONCLUSIONS

Topical corticosteroids are a beneficial treatment for CRSwNP and the adverse effects are minor, with benefits outweighing the risks. They improve symptoms, reduce polyp size and prevent polyp recurrence after surgery. Patients having sinus surgery may have a greater response to topical corticosteroids but further research is required.

Environmental bacteria and childhood asthma

BACKGROUND

We have previously found an inverse association of bacterial diversity with childhood asthma. It remains unclear whether certain bacteria account for the protective effect.

METHODS

The high variability of the bacterial 16S rRNA gene allows assessing diversity and specificity of bacterial communities by single-strand configuration polymorphism (SSCP). DNA was extracted from mattress dust samples of 489 school-age children from rural and suburban regions in Germany. A fragment of the bacteria-specific 16S rRNA gene was amplified by PCR, digested to single-strand DNA, and subjected to electrophoresis. The resulting band patterns reflect the underlying DNA sequences. The individual bands were tested for associations with asthma, hay fever, and atopy in quantitative and qualitative multivariable analyses. Significantly associated bands were isolated and sequenced. The sequences were compared to a database, and distinct bacteria were identified.

RESULTS

Seven of 76 independent bands were found to be inversely associated with asthma, atopic sensitization, and hay fever with odds ratios ranging from 0.17 to 0.73. The bands contained the sequences of Acinetobacter sp., Lactobacillus spp., Neisseria spp., Staphylococcus sciuri, Jeotgalicoccus sp., Corynebacterium spp., and others.

CONCLUSIONS

In a diverse microbial environment, certain bacteria may account for the protective effect on the development of asthma and atopy.

Differences in airway inflammation according to atopic status in patients with chronic rhinitis

Background

Chronic rhinitis is a heterogeneous group of diseases that cause nasal inflammation. And the nose may be a window into the lung in the concept of "one airway one disease."

Objective

This study was conducted to evaluate differences between the different forms of chronic rhinitis in terms of lower airway inflammation.

Methods

Patients that attended the allergy clinic and presented with moderate/severe persistent rhinitis symptoms for more than 1 year were enrolled. The patients with chronic rhinitis were classified into two groups (house dust mites [HDM]-sensitive allergic rhinitis [AR] or non-allergic rhinitis [NAR]) according to the presence of atopy, and additionally according to nasal polyposis and airway hyperresponsiveness, respectively. Medical records were reviewed and the mRNA expression levels of IL-5, IFN-γ, TGF-β1, IL-17A, and IL-25 were evaluated in induced sputum samples in each group.

Results

Induced sputum samples of 53 patients were evaluated. Patients with NAR were significantly older than patients with HDM-sensitive AR (p < 0.05). Nasal polyposis was more prevalent in NAR patients than in HDM-sensitive AR patients (10.2% vs. 62.5%, p < 0.001). The expression levels of IL-17A mRNA were higher in NAR patients, regardless of the presence of airway hyperresponsiveness (p = 0.005).

Conclusion

These results suggest that patients with different forms of chronic rhinitis could have different inflammatory environments in their lower airway and NAR patients might have bronchial inflammation related to the elevated levels of IL-17A compared to HDM-sensitive AR patients.

Pathophysiology, favoring factors, and associated disorders in otorhinosinusology

The pathogenesis of rhinosinusitis (RS) is related to inflammation, caused by infections in the acute form of the disease but also by other agents in the chronic forms. Cytology allows to evaluate the defensive components, such as hair cells and muciparous cells, while the presence in the nasal mucosa of eosinophils, mast cells, bacteria and/or fungal hyphae, or spores indicates the nasal pathology. The anatomic and physiologic characteristics of the otorhinosinusal system account for the frequent concomitant involvement of the different components. The pivotal pathophysiologic sites are the ostiomeatal complex, the spheno-ethmoidal recess, and the Eustachian tube. The latter is the link with acute otitis media (AOM), which is the most common disease in infants and children and has major medical, social, and economic effects. Moreover, because of the strict relationship between upper and lower airways, nasal sinus disease may contribute to asthma and sinusitis may be considered as an independent factor associated with frequent severe asthma exacerbations. Concerning the role of allergy, the available data do not permit to attribute a central role to atopy in sinusitis and thus allergy testing should not be a routine procedure, while an allergologic evaluation may be indicated in children with OM, especially when they have concomitant rhinitis.

Bacteriology and antibiotic resistance in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a prevalent health care problem that may be commonly encountered in patients desiring aesthetic or reconstructive rhinoplasty. The purpose of this article is to review the common bacterial pathogens associated with CRS, as well as patterns of bacterial resistance in this patient subset. Close understanding of microbial pathogens involved in CRS and their associated resistance patterns will guide facial plastic surgeons in optimally managing this important potential comorbidity, and in turn positively influence the outcome of rhinoplasty.

Rhinosinusitis and aspirin-exacerbated respiratory disease

Rhinosinusitis is a feature of aspirin-exacerbated respiratory disease (AERD), which in the initial phase is manifested as nasal congestion, mostly affecting females at the age of around 30 years on average. Subsequently, nasal inflammation progresses to chronic eosinophilic rhinosinusitis, asthma, nasal polyposis, and intolerance to aspirin and to other NSAIDs. While it has been long established that NSAIDs cause inhibition of cyclooxygenase-1 (COX-1), leading to excessive metabolism of arachidonic acid (AA) to cysteinyl-leukotrienes (cys-LTs), there is now evidence that both cytokines and staphylococcus superantigens amplify the inflammatory process exacerbating the disease. This paper gives a brief overview of the development of chronic rhinosinusitis (CRS) in sensitive patients, and we share our experience in the diagnosis and management of CRS in AERD.

Herpes simplex virus type 1 infection facilitates invasion of Staphylococcus aureus into the nasal mucosa and nasal polyp tissue

BACKGROUND

Staphylococcus aureus (S. aureus) plays an important role in the pathogenesis of severe chronic airway disease, such as nasal polyps. However the mechanisms underlying the initiation of damage and/or invasion of the nasal mucosa by S. aureus are not clearly understood. The aim of this study was to investigate the interaction between S. aureus and herpes simplex virus type 1 (HSV1) in the invasion of the nasal mucosa and nasal polyp tissue.

METHODOLOGY/PRINCIPAL FINDINGS

Inferior turbinate and nasal polyp samples were cultured and infected with either HSV1 alone, S. aureus alone or a combination of both. Both in turbinate mucosa and nasal polyp tissue, HSV1, with or without S. aureus incubation, led to focal infection of outer epithelial cells within 48 h, and loss or damage of the epithelium and invasion of HSV1 into the lamina propria within 72 h. After pre-infection with HSV1 for 24 h or 48 h, S. aureus was able to pass the basement membrane and invade the mucosa. Epithelial damage scores were significantly higher for HSV1 and S. aureus co-infected explants compared with control explants or S. aureus only-infected explants, and significantly correlated with HSV1-invasion scores. The epithelial damage scores of nasal polyp tissues were significantly higher than those of inferior turbinate tissues upon HSV1 infection. Consequently, invasion scores of HSV1 of nasal polyp tissues were significantly higher than those of inferior turbinate mucosa in the HSV1 and co-infection groups, and invasion scores of S. aureus of nasal polyp tissues were significantly higher than those of inferior turbinate tissues in the co-infection group.

CONCLUSIONS/SIGNIFICANCE

HSV1 may lead to a significant damage of the nasal epithelium and consequently may facilitate invasion of S. aureus into the nasal mucosa. Nasal polyp tissue is more susceptible to the invasion of HSV1 and epithelial damage by HSV1 compared with inferior turbinate mucosa.

Chronic rhinosinusitis in children--bacteriological analysis in terms of cytological examination

INTRODUCTION

The mechanisms of inflammatory response occurring in chronic rhinosinusitis in children are multifactorial. Besides the history and a physical examination, amongst diagnostic tools there are cytological and bacteriological examinations.

OBJECTIVES

1 Determining the nature of the bacterial flora present in the nasal cavities and paranasal sinuses in children with chronic rhinosinusitis amongst patients of The Department of Paediatric Otolaryngology,Warsaw Medical University. 2 Determining the relation between bacterial strains and cytological examination of nasal mucosa in children with chronic rhinosinusitis.

MATERIALS AND METHODS

The study group included 64 patients with chronic rhinosinusitis without polyps. The control group included 30 randomly chosen children. Diagnostic tests performed in both groups were: middle meatal culture and cytological examination from the inferior nasal concha and middle meatus. Statistical analysis was accomplished with Statistica 8.0.

CONCLUSIONS

Damage to the respiratory epithelial surface is understood as damage to the innate immune barrier, and repeated antibiotic therapy with the subsequent repopulation of the epithelium accidentally by various bacteria can become responsible for the pathogenic effect of bacteria in chronic rhinosinusitis.

Staphylococcus aureus induces eosinophil cell death mediated by α-hemolysin

Staphylococcus aureus, a major human pathogen, exacerbates allergic disorders, including atopic dermatitis, nasal polyps and asthma, which are characterized by tissue eosinophilia. Eosinophils, via their destructive granule contents, can cause significant tissue damage, resulting in inflammation and further recruitment of inflammatory cells. We hypothesised that the relationship between S. aureus and eosinophils may contribute to disease pathology. We found that supernatants from S. aureus (SH1000 strain) cultures cause rapid and profound eosinophil necrosis, resulting in dramatic cell loss within 2 hours. This is in marked contrast to neutrophil granulocytes where no significant cell death was observed (at equivalent dilutions). Supernatants prepared from a strain deficient in the accessory gene regulator (agr) that produces reduced levels of many important virulence factors, including the abundantly produced α-hemolysin (Hla), failed to induce eosinophil death. The role of Hla in mediating eosinophil death was investigated using both an Hla deficient SH1000-modified strain, which did not induce eosinophil death, and purified Hla, which induced concentration-dependent eosinophil death via both apoptosis and necrosis. We conclude that S. aureus Hla induces aberrant eosinophil cell death in vitro and that this may increase tissue injury in allergic disease.

Comorbidities between nose and skin allergy

PURPOSE OF REVIEW

This review focuses on comorbidities between nose and skin allergies. For this purpose, allergic rhinitis and chronic rhinosinusitis (CRS) were selected as examples of nasal disorders and atopic dermatitis and urticaria as examples of allergic skin disorders and the individual entities of both localizations were evaluated and compared in relation to their prevalence and coincidence, underlying pathophysiological mechanisms, genetic data and shared therapy options.

RECENT FINDINGS

The inter-relationships between atopic dermatitis and allergic rhinitis are the best studied, but even for the other comorbidities it was possible to demonstrate comparable pathomechanisms in addition to a high prevalence and coincidence, particularly in the case of atopically assisted forms. In this context, the interactions of IgE, mast cells and eosinophils play a special role, but genetic issues, the significance of epithelial barrier defects and colonization with Staphylococcus aureus are also important sharing issues.

SUMMARY

Allergic skin disorders such as atopic dermatitis and urticaria are frequently associated with comorbidities of the nose as well as allergic rhinitis and CRS. By contrast, different manifestations of these diseases involve the nose and the skin. These are not separate diseases but are linked by complex and currently unclear/insufficiently defined inter-relationships.

Pathophysiology of allergic inflammation

Allergic inflammation is due to a complex interplay between several inflammatory cells, including mast cells, basophils, lymphocytes, dendritic cells, eosinophils, and sometimes neutrophils. These cells produce multiple inflammatory mediators, including lipids, purines, cytokines, chemokines, and reactive oxygen species. Allergic inflammation affects target cells, such as epithelial cells, fibroblasts, vascular cells, and airway smooth muscle cells, which become an important source of inflammatory mediators. Sensory nerves are sensitized and activated during allergic inflammation and produce symptoms. Allergic inflammatory responses are orchestrated by several transcription factors, particularly NF-κB and GATA3. Inflammatory genes are also regulated by epigenetic mechanisms, including DNA methylation and histone modifications. There are several endogenous anti-inflammatory mechanisms, including anti-inflammatory lipids and cytokines, which may be defective in allergic disease, thus amplifying and perpetuating the inflammation. Better understanding of the pathophysiology of allergic inflammation has identified new therapeutic targets but developing effective novel therapies has been challenging. Corticosteroids are highly effective with a broad spectrum of anti-inflammatory effects, including epigenetic modulation of the inflammatory response and suppression of GATA3.

Mepolizumab, a humanized anti-IL-5 mAb, as a treatment option for severe nasal polyposis

BACKGROUND

Approximately 85% of nasal polyps (NPs) in white subjects are characterized by prominent eosinophilia. IL-5 is the key driver of eosinophilic differentiation and survival.

OBJECTIVE

We sought to investigate the therapeutic potential of inhibiting IL-5 with a humanized mAb as treatment for severe nasal polyposis.

METHODS

Thirty patients with severe nasal polyposis (grade 3 or 4 or recurrent after surgery) refractory to corticosteroid therapy were randomized in a double-blind fashion to receive either 2 single intravenous injections (28 days apart) of 750 mg of mepolizumab (n = 20) or placebo (n = 10). Change from baseline in NP score was assessed monthly until 1 month after the last dose (week 8). Computed tomographic scans were also performed at week 8.

RESULTS

Twelve of 20 patients receiving mepolizumab had a significantly improved NP score and computed tomographic scan score compared with 1 of 10 patients receiving placebo at week 8 versus baseline.

CONCLUSION

Mepolizumab achieved a statistically significant reduction in NP size for at least 1 month after dosing in 12 of 20 patients. IL-5 inhibition is a potential novel therapeutic approach in patients with severe eosinophilic nasal polyposis.

The Role of IgE Production in the Pathophysiology of Rhinitis and Rhinosinusitis

A multitude of potential etiologies exist for rhinitis and rhinosinusitis. These sinonasal disorders are heterogeneous entities that are best understood by evaluating the causative factors in each individual patient. More precise diagnosis permits accurate and effective treatment. The association of allergy with sinonasal symptoms has been described for decades; however, the specific relationship between allergy, rhinitis, and rhinosinusitis is complex. Considering allergy in terms of a systemic atopic disorder, along with a local inflammatory process mediated by IgE production in sinonasal tissues, is helpful in unveiling the complex connection between allergy, rhinitis, and rhinosinusitis. This article reviews recent literature regarding local IgE and sinonasal inflammatory conditions.

Genetics of rhinosinusitis

Suggestion for a potential genetic basis to chronic rhinosinusitis (CRS) is afforded by degree of inheritability suggested from family and twin studies, existence of CRS in simple mendelian diseases, and development of sinusitis as part of the phenotype of certain gene "knockout" murine models. Genetic association studies are expected to identify novel genes associated with CRS and suggest novel mechanisms implicated in disease development. Although these studies are subject to methodologic difficulties, associations of CRS and polymorphisms in more than 30 genes have been published, with single nucleotide polymorphisms in 3 (IL1A, TNFA, AOAH) replicated. While the individual risk conferred by these single nucleotide polymorphisms remains modest, taken as a group, they suggest an important implication of pathways of innate immune recognition and in regulation of downstream signaling in the development of CRS. In a demonstration of these techniques' potential to identify new targets for research, the authors present a functional investigation of LAMB1, the top-rated gene from a pooling-based genome-wide association study of CRS. Upregulation of gene expression in LAMB1 and associated laminin genes in primary epithelial cells from CRS patients implicates the extracellular matrix in development of CRS and offers a new avenue for further study.

Oral antifungal therapy for Fusarium-associated chronic rhinosinusitis

BACKGROUND

Fusarium is commonly reported as an organism found in fungus-associated chronic rhinosinusitis (CRS) yet it is known to be resistant to commonly used antifungal therapies. The goals of this work are to report the incidence of Fusarium-associated CRS in fungal cultures and to describe the treatment experience with oral antifungal agent aimed at this problem.

METHODS

Patients with sinus cultures obtained from 2005 through 2008 were retrospectively identified and their medical records were evaluated. Cultures were obtained in patients with recalcitrant rhinosinusitis when purulent discharge was observed. Patient response to the therapy was measured upon the basis of self reported symptom improvements and endoscopic examination.

RESULTS

In this 4-year period 2,570 outpatient fungal cultures were obtained and 194 (7.5%) were positive for Fusarium. These 194 positive cultures appeared in 94 individuals. Thirty-four tested positive multiple times. Twenty-three (24.5%) had severe recalcitrant CRS poorly responsive to standard therapies warranting antifungal therapy aimed at Fusarium. Fifteen individuals were treated with voriconazole, 5 with posaconazole, and 3 with both at separate times. Endoscopic evidence of initial improvement on therapy was evident in 16 of 23 patients (69.6%). Of 18 patients who could comment on their experience with the antifungal treatments, nearly 90% of them reported substantial improvement with the therapy. Nine (9/23; 39.1%) were forced to discontinue oral antifungal therapy due to untoward effects.

CONCLUSION

Fusarium appears in 7.55% of outpatient cultures of CRS. Of the patients testing positive for Fusarium, 25% received oral antifungal therapy. A positive response was seen in 16 of 23 (69.6%) while receiving other standard therapies. Since Fusarium is not routinely sensitive to commonly used antifungal agents, it warrants special attention.

Chronic rhinosinusitis with nasal polyps: elevated serum immunoglobulin E is associated with Staphylococcus aureus on culture

BACKGROUND

Recent data has implicated Staphylococcus aureus (SA) superantigen as a potential disease modifier in patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP). The objective of this work was to compare total serum immunoglobulin E (IgE) and serum eosinophils in patients with CRSwNP and CRS without nasal polyps (CRSsNP) based on culture results of the 3 most commonly isolated bacteria.

METHODS

Retrospective review at a tertiary rhinology referral center of patients with CRS over a 4-year period.

RESULTS

Bacterial cultures and immunologic data were obtained from 62 patients with CRSwNP and 34 patients with CRSsNP. SA was the most prevalent bacteria in the CRSwNP group, isolated in 19 patients (31%). Patients with elevated total serum IgE (>114 IU/mL) were more likely to have SA on culture (p = 0.04) in this population. The percent serum eosinophil levels in the SA+ group compared with the SA- group was not significant (6.0 vs 5.1, p = 0.17). Lund-Mackay computed tomography (CT) scores, but not Sino-Nasal Outcome Test 20 (SNOT-20) scores were significantly higher in the SA+ vs SA- group (p = 0.03) in patients with CRSwNP. The CRSsNP group demonstrated no difference in IgE or serum eosinophils between different bacterial groups.

CONCLUSION

Our findings suggest that there is an association between SA sinonasal presence and elevated total serum IgE in patients with CRSwNP. In addition, SA+ patients had higher Lund-Mackay CT scores, indicating a higher objective burden of disease in this group of patients.

Superantigen-induced glucocorticoid insensitivity in the recurrence of chronic rhinosinusitis with nasal polyps

OBJECTIVE

To investigate a potential mechanism by which superantigens could induce glucocorticoid insensitivity in chronic rhinosinusitis (CRS) patients.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary medical center.

SUBJECTS AND METHODS

Sinonasal polyps were obtained from CRS patients with nasal polyps (CRSwNP; 20 without recurrence, 18 with recurrent NP followed for 1.5-2.0 years) and nasal mucosa from 16 CRS patients without nasal polyps (CRSsNP). Specimens were tested by enzyme-linked immunosorbent assay for staphylococcal exotoxins (SEs) including SEA, SEB, SEC, SED, and toxic shock syndrome toxin type-1 (TSST-1) and assessed by immunohistochemistry for glucocorticoid receptor (GR) α and β, and the GRβ/GRα ratio was analyzed.

RESULTS

In CRSwNP, 13 of 18 (72.22%) subjects with subsequently recurrent NP, 11 of 20 (55.00%) subjects without NP recurrence, and 1 of 16 (6.25%) CRSsNP subjects with positive reactions for SEs were obtained. There were no positive results in controls. The expressions of GRβ in 3 CRS groups and controls were significantly different (all P < .05), and a similar increasing tendency of the GRβ/GRα ratio was found among groups besides the comparison of CRSwNP versus recurrent NP groups (P = .053). Furthermore, there was a clear trend of increased GRβ expression in the enzyme-linked immunosorbent assay (ELISA)-positive samples compared with ELISA-negative samples. Concerning GRα, the expression was enhanced significantly just in toxin-positive recurrent NP versus controls (P = .048), but the relative induction of GRβ was much higher, thereby leading to a higher GRβ/GRα ratio.

CONCLUSIONS

Bacterial superantigens may contribute to glucocorticoid insensitivity through induction of GRβ, which appears to be a marker of steroid insensitivity in CRSwNP.

Exacerbation of cigarette smoke-induced pulmonary inflammation by Staphylococcus aureus enterotoxin B in mice

Background

Cigarette smoke (CS) is a major risk factor for the development of COPD. CS exposure is associated with an increased risk of bacterial colonization and respiratory tract infection, because of suppressed antibacterial activities of the immune system and delayed clearance of microbial agents from the lungs. Colonization with Staphylococcus aureus results in release of virulent enterotoxins, with superantigen activity which causes T cell activation.

Objective

To study the effect of Staphylococcus aureus enterotoxin B (SEB) on CS-induced inflammation, in a mouse model of COPD.

Methods

C57/Bl6 mice were exposed to CS or air for 4 weeks (5 cigarettes/exposure, 4x/day, 5 days/week). Endonasal SEB (10 μg/ml) or saline was concomitantly applied starting from week 3, on alternate days. 24 h after the last CS and SEB exposure, mice were sacrificed and bronchoalveolar lavage (BAL) fluid and lung tissue were collected.

Results

Combined exposure to CS and SEB resulted in a raised number of lymphocytes and neutrophils in BAL, as well as increased numbers of CD8⁺ T lymphocytes and granulocytes in lung tissue, compared to sole CS or SEB exposure. Moreover, concomitant CS/SEB exposure induced both IL-13 mRNA expression in lungs and goblet cell hyperplasia in the airway wall. In addition, combined CS/SEB exposure stimulated the formation of dense, organized aggregates of B- and T- lymphocytes in lungs, as well as significant higher CXCL-13 (protein, mRNA) and CCL19 (mRNA) levels in lungs.

Conclusions

Combined CS and SEB exposure aggravates CS-induced inflammation in mice, suggesting that Staphylococcus aureus could influence the pathogenesis of COPD.

Staphylococci and staphylococcal superantigens in asthma and rhinitis: a systematic review and meta-analysis

BACKGROUND

There is a need for new treatment options of allergic respiratory diseases based on a better knowledge of their pathogenesis. An association between bacterial products and allergic airway diseases has been suggested by the results of human and animal studies that describe a link between Staphylococcus aureus enterotoxins and atopic diseases. The aim of the systematic review is to assess the evidence for a role of Staphylococcus aureus enterotoxins, as an environmental risk factor, for the development and/or the severity of asthma and allergic rhinitis.

METHODS

We performed a systematic review of controlled clinical studies in adults and/or children affected by asthma/early wheeze and/or allergic rhinitis. To be eligible, studies had to use reproducible methods to provide evidence of exposure to S. aureus, clinical outcome and disease severity.

RESULTS

Ten studies, published between 2000 and 2007, fulfilled all eligibility criteria. Patients with asthma or allergic rhinitis showed an increased prevalence of positivity for measures of exposure to S. aureus in nine studies: differences were statistically significant (P < 0.05) in seven studies. In a meta-analysis of study results, patients with asthma were more likely than controls to have serum-specific IgE to Staphylococcus aureus enterotoxins (OR = 3.3, 95% CI: 1.6-7.1, P = 0.002); similarly, patients with allergic rhinitis were more likely than controls to test positive for local or systemic exposure to Staphylococcus aureus and/or or its enterotoxins (OR = 2.4, 95% CI: 1.3-4.7, P = 0.008).

CONCLUSIONS

A potential role of S. aureus superantigens in allergic respiratory diseases is supported by results of this meta-analysis of clinical studies.

The role of anti-infectives in the treatment of refractory asthma

Refractory asthma not only has a significant effect on quality of life, but also imposes an economic burden on society. Increasing evidence suggests that there is a pathophysiologic interaction between infection and allergic disease in patients with severe or refractory asthma. Therapeutic trials of macrolides and azoles are being utilized in some patients with refractory asthma who fail to respond to standard therapy. In this article we review the definition of refractory asthma and the potential pathophysiologic interactions between infection and allergic disease. Emerging data suggest that microorganisms and their byproducts may be a therapeutic target in the therapy of patients with severe or refractory asthma.

Actual concepts in rhinosinusitis: a review of clinical presentations, inflammatory pathways, cytokine profiles, remodeling, and management

Rhinosinusitis (RS) is a heterogeneous group of diseases. It is a significant and increasing health problem that affects about 15% of the population in Western countries. It has a substantial impact on patients' health-related quality of life and daily functioning and represents a huge financial burden to society and the health care system as a result of the direct and indirect costs. In addition, RS is not well-understood, and little is known about the etiology and pathophysiology. In the past decade, many papers have been published that have changed our understanding of RS. RS is commonly classified into acute and chronic RS based on symptom duration. In acute RS, an inflammatory reaction initiated by a viral infection characterizes most uncomplicated, mild to moderate cases. Therefore, the first line of treatment for these cases are intranasal steroids and not antibiotics. In severe and complicated cases, antibiotics combined with topical steroids remain the treatment of choice. On the other hand, chronic RS is actually subdivided into two distinct entities (chronic rhinosinusitis with and without polyps), as growing evidence indicates that these entities have specific inflammatory pathways and cytokine profiles. The authors review recent data regarding the clinical presentations, cytokine profiles, tissue remodeling, and modalities of treatment for each form of RS.

Is chronic rhinosinusitis caused by persistent respiratory virus infection?

Background

Many chronic rhinosinusitis (CRS) patients recall an upper respiratory tract infection as the inciting event of their chronic illness. Viral infections have been shown to cause obstruction of the osteomeatal complex, which is likely to be a critical step in the development of CRS. There is clear overlap between the pathogenesis of CRS and asthma. Infections with respiratory viruses in childhood increase the risk of subsequently developing asthma. Viral infections in established asthmatics are associated with acute exacerbations. We sought to determine whether respiratory viruses could be detected within the sinonasal mucosa of CRS patients using polymerase chain reaction (PCR) techniques.

Methods

Sinus mucosa was sampled from 13 patients with CRS and 2 patients with normal sinuses. PCR was used to look for common respiratory viruses (parainfluenza 1, 2, and 3; respiratory syncytial virus [RSV]; human metapneumovirus [hMPV]; adenovirus [ADV]; rhinovirus; coronavirus; bocavirus [BoV]; cytomegalovirus [CMV]; and influenza A and B).

Results

No respiratory viruses were detected in any of the samples.

Conclusion

Persistence of respiratory viruses within the sinonasal mucosa is unlikely to be a cause of ongoing inflammation in CRS. The possibility remains that a transient viral infection provides the initial inflammatory stimulus. © 2011 ARS‐AAOA, LLC.

Evidence-based management of nasal polyposis by intranasal corticosteroids: from the cause to the clinic

BACKGROUND

Nasal polyposis is an inflammatory disorder involving the mucosa of the nose and paranasal sinuses and affecting approximately 2-4% of the general population.

METHODS

A literature search of Medline and Embase was conducted to obtain an overview of the epidemiology, pathophysiology, and current treatment of nasal polyposis, focusing on evidence-based efficacy of intranasal corticosteroids (INSs) as primary and postoperative therapy. Recent research on INSs in nasal polyp treatment, along with notable historic findings, was reviewed.

RESULTS

Nasal polyps are mostly characterized by eosinophil infiltration, a complex inflammation of nasal mucosa, and possibly production of polyclonal IgE. Current treatment modalities include INSs, oral corticosteroids, and surgery; surgery is generally limited to those with an insufficient response to medical treatment. Because of their effects on eosinophil-dominated inflammation, INSs and oral corticosteroids are the primary medical treatment strategies. The very low (≤1%) systemic bioavailability of newer INSs minimizes the systemic adverse effects seen with oral corticosteroids.

CONCLUSION

Based on randomized, controlled trials, guidelines recommend INSs as first-line therapy for nasal polyps and for care after polypectomy. Clinical data suggest INSs are effective in reducing polyp size and relieving nasal symptoms. INS treatment has also reduced nasal polyp recurrence in patients undergoing functional endoscopic sinus surgery. Treatment with these mainstay options has been found to improve quality of life, which, along with symptom improvement, is a key factor in disease treatment.

T cell inflammatory response, Foxp3 and TNFRS18-L regulation of peripheral blood mononuclear cells from patients with nasal polyps-asthma after staphylococcal superantigen stimulation

BACKGROUND

Staphylococcal superantigens may modulate airway inflammatory disease.

OBJECTIVE

We assessed the effect of Staphylococcus aureus enterotoxin B (SEB) on T cell activation in patients with nasal polyps and asthma, and its possible link to aspirin hypersensitivity.

METHODS

Leucocytes were isolated from five healthy subjects (controls), five asthmatics with nasal polyps without (NP-ATA) and five with aspirin-induced asthma (NP-AIA). Cells were incubated with increasing concentrations of SEB for 4 and 18 h. Release of T(H)1/T(H)2 cytokines was assessed by Cytometric Bead-Array. Foxp3 and TNFRS18-L expression were analysed by qPCR and flow cytometry.

RESULTS

After 4 and 18 h, SEB significantly increased IFN-gamma, IL-4, TNF-alpha, IL-5 and IL-2 concentrations in supernatants of both NP polyp groups compared with controls. Baseline Foxp3 was significantly decreased in both NP-asthma groups. Incubation with SEB for 4 h induced a limited up-regulation of Foxp3 in NP-AIA patients, which was switched off consecutively. Foxp3 was significantly up-regulated in the control group after 18 h, but not in the NP-asthmatic groups. In parallel, TNFRS18-L mRNA significantly increased after 18 h in the NP-asthma groups compared with control subjects. This molecule was highly expressed in CD11c(+)CD14(+) cells and its levels increased after 18 and 24 h culture in the NP-asthma patients.

CONCLUSION

SEB induces both T(H)1 and T(H)2 pro-inflammatory responses in patients with nasal polyps and asthma regardless of the presence of aspirin hypersensitivity. The nature of this response may be linked to a basal deficiency of Foxp3 observed in the NP-asthmatic patients and/or to the up-regulation of TNFRS18-L on monocytes/dendritic cell precursors.

Generation, characterization, and epitope mapping of neutralizing and protective monoclonal antibodies against staphylococcal enterotoxin B-induced lethal shock

T-cell stimulating activity of Staphylococcal enterotoxin B (SEB) is an important factor in the pathogenesis of certain staphylococcal diseases including SEB mediated shock. SEB is one of the most potent superantigens known and treatment of SEB induced shock remains a challenge. We generated and characterized murine monoclonal antibodies (mAbs) to SEB in mice. We tested mAbs neutralize mitogenic effects of SEB in vitro and in vivo with T-cell proliferation assays and 2 murine models for SEB induced lethal shock (SEBILS). Epitope mapping suggests that all these mAbs recognize conformational epitopes that are destroyed by deleting the C terminus of the protein. Further site-directed mutagenesis identified potential residues involved in binding to SEB that differ between Methicillin resistant and sensitive Staphylococcus aureus strains. Only mAb 20B1 was effective as a monotherapy in treating SEBILS in HLA DR3 transgenic mice, which exhibit enhanced sensitivity to SEB. It is noteworthy that mAbs, 14G8 and 6D3 were not protective when given alone in the HLA DR3 mice but their efficacy of protection could be greatly enhanced when mAbs were co-administered simultaneously. Our data suggest combinations of defined mAbs may constitute a better treatment strategy and provide a new insight for the development of passive immunotherapy.

Clinical and immunological determinants of severe/refractory asthma (SRA): association with Staphylococcal superantigen-specific IgE antibodies

BACKGROUND

Demographic and immunological determinants of severe refractory asthma (SRA) are not well characterized. Because Staphylococcus aureus enterotoxins with superantigenic activity have been associated with upper and lower airway inflammation, we aimed to evaluate the association of sensitization to Staphylococcal enterotoxins with asthma severity and various asthma phenotypes.

METHODS

The study included 109 patients with SRA diagnosed according to the American Thoracic Society Workshop 2000, and 101 patients with nonsevere asthma, followed for at least 12 months. Specific IgE to Staphylococcus enterotoxins and total IgE and eosinophil cationic protein concentrations were measured in serum with immunoassays.

FINDINGS

A significant risk for severe asthma was associated with female gender [Odds Ratio (OR) = 2.04], history of wheezing in childhood (OR = 2.47), presence of hypersensitivity to aspirin (OR = 1.96) and with body mass index (OR = 3.08). The mean level of enterotoxin-specific IgE was 3-fold higher in patients with severe asthma when compared to patients with nonsevere asthma (P = 0.01). Serum-specific IgE to enterotoxins was significantly associated with low respiratory function parameters (FEV₁, FEV₁/FVC and MEF 25/75) and increased airway reversibility in response to albuterol. The presence of specific IgE to enterotoxin carried a significant risk for patients to have serum total IgE level above 100 kU/l (OR = 7.84).

INTERPRETATION

Specific immunological response to enterotoxins is associated with clinical and immunological parameters of asthma severity, suggesting a role for Staphylococcal enterotoxins in the asthma pathogenesis.

Presence of IL-5 protein and IgE antibodies to staphylococcal enterotoxins in nasal polyps is associated with comorbid asthma

BACKGROUND

Nasal polyps often are associated with asthma. The phenotype of these patients is unknown.

OBJECTIVE

To identify the mucosal factors associated with asthma comorbidity, we analyzed the inflammatory patterns of nasal polyps.

METHODS

Nasal polyps from 70 Belgian patients, 34% with asthma, were analyzed for type of inflammation, T-cell cytokines, and IgE antibodies to Staphylococcus aureus enterotoxins. The same investigations were repeated in 93 Chinese patients with polyps, a group with a low asthma comorbidity rate (8%).

RESULTS

In Belgian patients with polyps, 54% of samples showed eosinophilic inflammation. A classification tree evaluation identified IL-5 as the main positive determinant. Enterotoxin IgE in tissue (37%) was associated with significantly increased total IgE and eosinophil cationic protein concentrations. Expression of enterotoxin IgE, total IgE at greater than 1,442 kU/L, and eosinophil cationic protein at greater than 17,109 μg/L in samples with a total IgE concentration of greater than 246 kU/L significantly predicted asthma (odds ratio, 5.8-13). Only 7.5% of the samples from Chinese patients with polyps showed eosinophilic inflammation. IL-5 was confirmed as a positive determinant of eosinophilic inflammation, and enterotoxin IgE in tissue (17% of patients) was associated with significantly increased total IgE and eosinophil cationic protein concentrations. The expression of IL-5 or total IgE at greater than 790 kU/L in samples with an IL-5 concentration of greater than 194 pg/mL significantly predicted comorbid asthma (odds ratio, 17.2-96).

CONCLUSION

Mucosal inflammation in nasal polyps orchestrated by T(H)2 cytokines and amplified by S aureus enterotoxins is characterized by an increased eosinophilic inflammation and formation of IgE antibodies. This phenotype is associated with comorbid asthma in white and Asian patients with nasal polyps.

Staphylococcus aureus invades the epithelium in nasal polyposis and induces IL-6 in nasal epithelial cells in vitro

BACKGROUND

Staphylococcus aureus has been associated with chronic rhinosinusitis with nasal polyps (CRSwNP) pathogenesis but its role is still controversially discussed. Here, we demonstrate S. aureus detection in the mucosa of CRSwNP. In addition, intracellular residency of S. aureus in nasal polyp epithelial cells (NPECs) and its capability to induce TH-2 cytokines were analyzed in vitro.

METHODS

Staphylococcus aureus detection in CRSwNP (n = 25), CRS without polyps (CRSsNP, n = 5), and turbinate mucosa (TM, n = 10) was performed by peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) and microbial cultivation from tissue biopsies. Intracellular residency was examined by intracellular persistence assay and electron microscopy. IL-6 and IL-13 responses to S. aureus infection and supernatants were quantified by ELISA.

RESULTS

Peptide nucleic acid-fluorescence in situ hybridization positive bacterial cells were significantly increased in the epithelium of CRSwNP (17/25) compared to CRSsNP (0/5) and TM (1/10). Good concordance of PNA-FISH results and S. aureus cultivation was found applying Cohen's κ for CRSwNP (κ = 0.841) and TM (κ = 1.0). Intracellular persistence assay with S. aureus strain Newman and its corresponding small-colony variant mutant strain III33 demonstrated intracellular survival and replication of S. aureus within NPECs. Both S. aureus strains significantly induced IL-6 but not IL-13 in infected NPECs and in NPECs challenged with corresponding staphylococcal supernatants.

CONCLUSION

Invasion of the epithelium by S. aureus was a phenomenon seen predominantly in CRSwNP. Regardless of an intra- or extracellular localization in the epithelium, S. aureus is capable to induce IL-6 synthesis in vitro and thus may contribute to the TH-2 cytokine pattern in CRSwNP.

Staphylococcal enterotoxins

Staphylococcus aureus (S. aureus) is a Gram positive bacterium that is carried by about one third of the general population and is responsible for common and serious diseases. These diseases include food poisoning and toxic shock syndrome, which are caused by exotoxins produced by S. aureus. Of the more than 20 Staphylococcal enterotoxins, SEA and SEB are the best characterized and are also regarded as superantigens because of their ability to bind to class II MHC molecules on antigen presenting cells and stimulate large populations of T cells that share variable regions on the β chain of the T cell receptor. The result of this massive T cell activation is a cytokine bolus leading to an acute toxic shock. These proteins are highly resistant to denaturation, which allows them to remain intact in contaminated food and trigger disease outbreaks. A recognized problem is the emergence of multi-drug resistant strains of S. aureus and these are a concern in the clinical setting as they are a common cause of antibiotic-associated diarrhea in hospitalized patients. In this review, we provide an overview of the current understanding of these proteins.

Staphylococcus aureus enterotoxin B augments granulocyte migration and survival via airway epithelial cell activation

BACKGROUND

Staphylococcus aureus enterotoxin B (SEB) has recently been postulated to be involved in the pathology of granulocyte-dominated disease. Studying the immunologic interaction between SEB and airway epithelial cells in immortalized cell lines or long-term epithelial cell cultures has obvious disadvantages.

METHODS

We used a novel technique of freshly isolated and purified human nasal epithelial cells (HNEC) from healthy, nonallergic individuals, which were incubated for 24 h without/with SEB at different concentrations. Chemokine production was evaluated in the supernatant using Cytometric Bead Array. The chemotactic activity of the supernatant was studied in vitro using a Boyden chamber. Survival was evaluated with flow cytometry, using propidium iodide to identify dead cells.

RESULTS

Staphylococcus aureus enterotoxin B showed a dose-dependent induction of interferon-inducible protein-10, monokine induced by interferon-gamma, regulated upon activation normal T cell expressed and secreted, monocyte chemoattractant protein 1 (MCP-1) and granulocyte colony stimulating factor production by epithelial cells in vitro. The supernatant of epithelial cells had chemotactic activity for granulocytes in vitro, which was enhanced in the supernatant of SEB-stimulated epithelial cells. Reduced number of propidium iodide positive granulocytes was found in the conditions where supernatant of SEB-stimulated epithelial cells was applied.

CONCLUSION

Staphylococcus aureus enterotoxin B exerts a direct pro-inflammatory effect on HNEC, with induction of chemokine and growth factor release, resulting in the migration and prolonged survival of granulocytes in vitro.

Incidence of staphylococcal colonization and of the 753Q Toll-like receptor 2 variant in nasal polyposis

BACKGROUND

The impact of Staphylococcus aureus on the development of chronic sinusitis with nasal polyps (nasal polyposis [NP]) is a controversial discussion because different S. aureus colonization rates have been reported. Aside from the presence of a microbial stimulus, elements of innate immunity such as Toll-like receptors (TLRs) and/or impaired TLR function could be relevant for the development of this disease. Because the 753Q TLR2 variant may predispose to staphylococcal infection, we simultaneously analyzed staphylococcal colonization and the R753Q TLR2 single nucleotide polymorphism (SNP) in NP.

METHODS

Sixty-eight patients with NP (47 men and 21 women; mean age [+/-SD], 51.8 years [16.3]) and 51 controls (32 men and 19 women; mean age [+/-SD], 36.3 years [12.2]) were included. Patient characteristics studied included status of allergy, asthma, aspirin intolerance, and endoscopic and CT polyp score. For detection of bacteria, standard procedures of bacteriology and 16S rRNA gene sequencing were used. The R753Q TLR2 polymorphism was studied by allelic discrimination assay.

RESULTS

Overall, 128 isolates were cultured from 68 NP specimens, with Staphylococcus epidermidis and S. aureus being the most frequent bacterial isolates. Other bacterial species were infrequently detected. Fifty-nine isolates were cultured from 51 controls. Similarly, S. epidermidis and S. aureus were the most frequent bacterial isolates. S. aureus colonization was significantly increased in NP (p < 0.05). However, SNP genotyping results showed no association of the 753Q TLR2 variant with NP.

CONCLUSION

Although S. aureus detection was increased in NP, nasal polyp pathology is not related to the 753Q TLR2 variant.

Characterization of bacterial and fungal biofilms in chronic rhinosinusitis

BACKGROUND

Conclusive evidence exists that biofilms are present on the mucosa of chronic rhinosinusitis (CRS) patients. Less is known about the species constituting these biofilms. This study developed a fluorescence in situ hybridization (FISH) protocol for characterization of bacterial and fungal biofilms in CRS.

METHODS

Fifty CRS patients and 10 controls were recruited. Bacteria FISH probes for Staphylococcus aureus, Haemophilus influenzae, and Pseudomonas aeruginosa and a universal probe for fungi were applied to sinus mucosal specimens and then analyzed using confocal scanning laser microscopy.

RESULTS

Thirty-six of 50 CRS patients had biofilms present in contrast to 0/10 controls, suggesting a role for biofilms in the pathogenesis of this disease. S. aureus was the most common biofilm-forming organism. Eleven of 50 CRS patients had characteristic fungal biofilms present.

CONCLUSION

This is the largest study of biofilms in CRS. It has validated mucosal tissue cryopreservation for delayed biofilm analysis. Fungal biofilms have been identified and the importance of S. aureus biofilms in the polymicrobial etiology of CRS is highlighted.