Staphylococcus aureus controls interleukin-5 release in upper airway inflammation

Sensitization to Staphylococcus Enterotoxin: Relationship with Aspects of Disease Severity

Background/Objective: Sensitization to specific IgE Staphylococcus aureus enterotoxins (SEs) is associated with an increased risk for severe asthma development. Limited data exist regarding the association of seropositivity for specific IgE SEs and the different aspects of severe asthma. We aimed to determine whether the presence of SEs is associated with asthma-related parameters such as inflammatory cells in the airways, features of airway remodeling, and other variables relating to asthma assessment and severity. Methods: Fifty patients with severe asthma were recruited in the study. Demographics, comorbidities, asthma duration, and asthma medication were recorded by treating physicians. Specific IgE SE measurement, lung function, atopic status, asthma control test (ACT), sputum induction, bronchoscopy with BAL, and indices of airway remodeling were also assessed. Results: Twelve patients were positive to enterotoxin sensitization. Patients seropositive to specific IgE SEs significantly differed in regard to FEV1% pred and FEV1/FVC ratio compared to seronegative ones. Analyzing the inflammatory variables obtained from induced sputum, BAL, and endobronchial biopsies, the only significant difference was that of smooth muscle area (SMA), which was greater in specific IgE SE seropositive patients. The multivariate linear regression analysis showed two significant associations of specific IgE SE seropositivity. We found a negative with FEV1% pred with beta standardized coefficient 95%CI -0.054 (-0.083, -0.031), p < 0.001, and a positive with SMA with beta standardized coefficient 95%CI 0.054 (0.081, 0.037), p < 0.001. Conclusions: Seropositivity to specific IgE SEs in severe asthma is associated with more severe airflow limitation, obstruction, and upregulation in SMA, indicating a possible role in the remodeling process.

The Impact of Antibiotics and Steroids on the Nasal Microbiome in Patients with Chronic Rhinosinusitis: A Systematic Review According to PICO Criteria

BACKGROUND

The nasal microbiome represents the main environmental factor of the inflammatory process in chronic rhinosinusitis (CRS). Antibiotics and steroids constitute the mainstay of CRS therapies. However, their impact on microbial communities needs to be better understood. This systematic review summarizes the evidence about antibiotics' and steroids' impact on the nasal microbiota in patients with CRS.

METHODS

The search strategy was conducted in accordance with the PRISMA guidelines for systematic reviews. The authors searched all papers in the three major medical databases (PubMed, Scopus, and Cochrane Library) using the PICO tool (population, intervention, comparison, and outcomes). The search was carried out using a combination of the key terms "Microbiota" or "Microbiome" and "Chronic Rhinosinusitis".

RESULTS

Overall, 402 papers were identified, and after duplicate removal (127 papers), excluding papers off-topic (154) and for other structural reasons (110), papers were assessed for eligibility; finally, only 11 papers were included and summarized in the present systematic review. Some authors used only steroids, other researchers used only antibiotics, and others used both antibiotics and steroids. With regard to the use of steroids as exclusive medical treatment, topical mometasone and budesonide were investigated. With regard to the use of antibiotics as exclusive medical treatments, clarithromycin, doxycycline, roxithromycin, and amoxicillin clavulanate were investigated. Regarding the use of both antibiotics and steroids, two associations were investigated: systemic prednisone combined with amoxicillin clavulanate and topical budesonide combined with azithromycin.

CONCLUSIONS

The impact that therapies can have on the nasal microbiome of CRS patients is very varied. Further studies are needed to understand the role of the nasal microbiome, prevent CRS, and improve therapeutic tools for personalized medicine tailored to the individual patient.

Pathophysiology and management of Staphylococcus aureus in nasal polyp disease

INTRODUCTION

Staphylococcus aureus (S. aureus) is a common pathogen that frequently colonizes the sinonasal cavity. Recent studies demonstrated the essential role of Staphylococcus aureus in the pathophysiology of uncontrolled severe chronic rhinosinusitis with nasal polyps (NP) by initiating an immune response to the germ and its products, resulting in type 2 inflammation.

AREAS COVERED

This review aims to summarize the evidence for the role of S. aureus in the development of NP disease including S. aureus-related virulence factors, the pathophysiologic mechanisms used by S. aureus, and the synergistic effects of S. aureus and other pathogens. It also describes the current management of S. aureus associated with NPs as well as potential therapeutic strategies that are used in clinical practice.

EXPERT OPINION

S. aureus is able to damage the nasal mucosal epithelial barrier, impair the clearance of the host immune system, and trigger adaptive and innate immune reactions which lead to the formation of inflammation and nasal polyp growth. Further studies should focus on the development of novel therapeutic strategies, such as biologics, bacteriophages, probiotics, and nanomedicine, which could be used to treat S. aureus and its immunological consequences in the future.

Disturbed microbiota-metabolites-immune interaction network is associated with olfactory dysfunction in patients with chronic rhinosinusitis

Purpose

Olfactory dysfunction (OD) is a debilitating symptom frequently reported by patients with chronic rhinosinusitis (CRS) and it is associated with a dysregulated sinonasal inflammation. However, little information is available about the effect of the inflammation-related nasal microbiota and related metabolites on the olfactory function in these patients. Therefore, the current study aimed to investigate the nasal microbiota-metabolites-immune interactions and their role in the pathogenesis of OD in CRS patients.

Methods

23 and 19 CRS patients with and without OD, respectively, were enrolled in the present study. The "Sniffin' Sticks" was used to measure the olfactory function, while the metagenomic shotgun sequencing and the untargeted metabolite profiling were performed to assess the differences in terms of the nasal microbiome and metabolome between the two groups. The levels of nasal mucus inflammatory mediators were investigated by a multiplex flow Cytometric Bead Array (CBA).

Results

A decreased diversity in the nasal microbiome from the OD group compared to the NOD group was evidenced. The metagenomic analysis revealed a significant enrichment of Acinetobacter johnsonii in the OD group, while Mycoplasma arginini, Aeromonas dhakensis, and Salmonella enterica were significantly less represented (LDA value > 3, p < 0.05). The nasal metabolome profiles were significantly different between the OD and NOD groups (P < 0.05). The purine metabolism was the most significantly enriched metabolic subpathway in OD patients compared with NOD patients (P < 0.001). The expressions of IL-5, IL-8, MIP-1α, MCP-1, and TNF were statistically and significantly increased in the OD group (P < 0.05). All these data, including the dysregulation of the nasal microbiota, differential metabolites, and elevated inflammatory mediators in OD patients demonstrated a clear interaction relationship.

Conclusion

The disturbed nasal microbiota-metabolite-immune interaction networks may be implicated in the pathogenesis of OD in CRS patients and the underlying pathophysiological mechanisms need to be further investigated in future studies.

Treatment Strategy of Uncontrolled Chronic Rhinosinusitis with Nasal Polyps: A Review of Recent Evidence

Chronic rhinosinusitis (CRS) is recognized as a heterogeneous disease with a wide range of clinical features, resulting in significant morbidity and cost to the healthcare system. While the phenotypic classification is determined by the presence or absence of nasal polyps and comorbidities, the endotype classification has been established based on molecular biomarkers or specific mechanisms. Research on CRS has now developed based on information based on three major endotypes: types 1, 2, and 3. Recently, biological therapies targeting type 2 inflammation have been clinically expanded and may be applied to other inflammatory endotypes in the future. The purpose of this review is to discuss the treatment options according to the type of CRS and summarize recent studies on new therapeutic approaches for patients with uncontrolled CRS with nasal polyps.

Translating the biology of β common receptor-engaging cytokines into clinical medicine

The family of cytokines that comprises IL-3, IL-5, and GM-CSF was discovered over 30 years ago, and their biological activities and resulting impact in clinical medicine has continued to expand ever since. Originally identified as bone marrow growth factors capable of acting on hemopoietic progenitor cells to induce their proliferation and differentiation into mature blood cells, these cytokines are also recognized as key mediators of inflammation and the pathobiology of diverse immunologic diseases. This increased understanding of the functional repertoire of IL-3, IL-5, and GM-CSF has led to an explosion of interest in modulating their functions for clinical management. Key to the successful clinical translation of this knowledge is the recognition that these cytokines act by engaging distinct dimeric receptors and that they share a common signaling subunit called β-common or βc. The structural determination of how IL-3, IL-5, and GM-CSF interact with their receptors and linking this to their differential biological functions on effector cells has unveiled new paradigms of cell signaling. This knowledge has paved the way for novel mAbs and other molecules as selective or pan inhibitors for use in different clinical settings.

The Changes in Bacterial Microbiome Associated with Immune Disorder in Allergic Respiratory Disease

Allergic respiratory disease is a worldwide and increasingly prevalent health problem. Many researchers have identified complex changes in the microbiota of the respiratory and intestinal tracts in patients with allergic respiratory diseases. These affect immune response and influence the progression of disease. However, the diversity of bacterial changes in such cases make it difficult to identify a specific microorganism to target for adjustment. Recent research evidence suggests that common bacterial variations present in allergic respiratory disease are associated with immune disorders. This finding could lead to the discovery of potential therapeutic targets in cases of allergic respiratory disease. In this review, we summarize current knowledge of bacteria changes in cases of allergic respiratory disease, to identify changes commonly associated with immune disorders, and thus provide a theoretical basis for targeting therapies of allergic respiratory disease through effective modulation of key bacteria.

Chronic Rhinosinusitis, S. aureus Biofilm and Secreted Products, Inflammatory Responses, and Disease Severity

Chronic rhinosinusitis (CRS) is a persistent inflammation of the nasal cavity and paranasal sinuses associated with tissue remodelling, dysfunction of the sinuses' natural defence mechanisms, and induction of different inflammatory clusters. The etiopathogenesis of CRS remains elusive, and both environmental factors, such as bacterial biofilms and the host's general condition, are thought to play a role. Bacterial biofilms have significant clinical relevance due to their potential to cause resistance to antimicrobial therapy and host defenses. Despite substantial medical advances, some CRS patients suffer from recalcitrant disease that is unresponsive to medical and surgical treatments. Those patients often have nasal polyps with tissue eosinophilia, S. aureus-dominant mucosal biofilm, comorbid asthma, and a severely compromised quality of life. This review aims to summarise the contemporary knowledge of inflammatory cells/pathways in CRS, the role of bacterial biofilm, and their impact on the severity of the disease. Here, an emphasis is placed on S. aureus biofilm and its secreted products. A better understanding of these factors might offer important diagnostic and therapeutic perceptions for recalcitrant disease.

Periostin as a biomarker in chronic rhinosinusitis: A contemporary systematic review

BACKGROUND

The role of periostin, a matricellular protein encoded by the POSTN gene, in chronic rhinosinusitis with nasal polyposis (CRSwNP) is reviewed. Periostin is considered a potential biomarker of endotype and may be useful for evaluating response to treatment.

METHODS

Search terms in PubMed and Web of Science (1990-March 2022) included: ((periostin) OR (POSTN)) AND ((sinusitis) OR (nasal polyp) OR (CRSwNP) OR (CRS). The primary outcomes were differences in tissue, serum, and nasal lavage between CRSwNP and CRS without NP (CRSsNP) or controls. Associated factors reported to affect periostin expression, data regarding participants' clinical characteristics, disease endotypes, laboratory methods, and samples' origin were also pooled. Studies on <10 patients were excluded.

RESULTS

Out of 101 records harvested through database searching, 29 prospective cross-sectional or case-control studies were eligible for review and qualitative analysis. Tissue sample origin, concurrent infection, current and past medication, primary or recurrent disease, allergic rhinitis, and smoking status should be considered as confounding factors for periostin levels. Periostin and POSTN messenger RNA (mRNA) levels were consistently and significantly higher in CRSwNP than CRSsNP and controls. Despite the distinctly different inflammation patterns among CRSwNP endotypes, periostin-related remodeling patterns seemed to be similar.

CONCLUSION

Tissue and serum periostin levels, and POSTN expression appear elevated in CRSwNP, especially in eosinophilic inflammation, compared to CRSsNP and controls. Disease severity and comorbidities are also reflected in periostin and POSTN values. Carefully designed prospective studies may establish the role of periostin as a biomarker in CRSwNP and allow its incorporation in clinical practice.

S. aureus and IgE-mediated diseases: pilot or copilot? A narrative review

INTRODUCTION

S. aureus is a major opportunistic pathogen that has been implicated in the pathogenesis of several chronic inflammatory diseases including bronchial asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), chronic spontaneous urticaria (CSU), and atopic dermatitis. S. aureus can induce the production of both polyclonal and specific IgE that can elicit an inflammatory cascade.

AREAS COVERED

The link between the sensitization to S. aureus enterotoxins and the severity of several chronic inflammatory diseases is reviewed in detail, as well as its therapeutic implications.

EXPERT OPINION

An anti-IgE strategy to inhibit S. aureus enterotoxins would be a valid approach to treat several endotypes of severe asthma, CRSwNP and CSU in which IgE against S. aureus enterotoxins should represent, not only a marker of severity of the diseases but also a target of a treatment.

Endotypes of chronic rhinosinusitis: Relationships to disease phenotypes, pathogenesis, clinical findings, and treatment approaches

Chronic rhinosinusitis (CRS) is a common clinical syndrome that produces significant morbidity and costs to our health system. The study of CRS has progressed from an era focused on phenotype to include endotype-based information. Phenotypic classification has identified clinical heterogeneity in CRS based on endoscopically observed features such as presence of nasal polyps, presence of comorbid or systemic diseases, and timing of disease onset. More recently, laboratory-based findings have established CRS endotype based upon specific mechanisms or molecular biomarkers. Understanding the basis of widespread heterogeneity in the manifestations of CRS is advanced by findings that the three main endotypes, Type 1, 2, and 3, orchestrate the expression of three distinct large sets of genes. The development and use of improved methods of endotyping disease in the clinic are ushering in an expansion of the use of biological therapies targeting Type 2 inflammation now and perhaps other inflammatory endotypes in the near future. The purpose of this review is to discuss the phenotypic and endotypic heterogeneity of CRS from the perspective of advancing the understanding of the pathogenesis and improvement of treatment approaches and outcomes.

Enhancing Human Superorganism Ecosystem Resilience by Holistically ‘Managing Our Microbes’

Microbes in the 21st century are understood as symbionts ‘completing’ the human ‘superorganism’ (Homo sapiens plus microbial partners-in-health). This paper addresses a significant paradox: despite the vast majority of our genes being microbial, the lack of routine safety testing for the microbiome has led to unintended collateral side effects from pharmaceuticals that can damage the microbiome and inhibit innate ‘colonization resistance’ against pathobionts. Examples are discussed in which a Microbiome First Medicine approach provides opportunities to ‘manage our microbes’ holistically, repair dysbiotic superorganisms, and restore health and resilience in the gut and throughout the body: namely, managing nosocomial infections for Clostridioides difficile and Staphylococcus aureus and managing the gut and neural systems (gut–brain axis) in autism spectrum disorder. We then introduce a risk analysis tool: the evidence map. This ‘mapping’ tool was recently applied by us to evaluate evidence for benefits, risks, and uncertainties pertaining to the breastmilk ecosystem. Here, we discuss the potential role of the evidence map as a risk analysis methodology to guide scientific and societal efforts to: (1) enhance ecosystem resilience, (2) ‘manage our microbes’, and (3) minimize the adverse effects of both acute and chronic diseases.

The Expression and Regulation of Na+-K+-ATPase in Nasal Epithelial Cells of Chronic Rhinosinusitis with Nasal Polyps

OBJECTIVE

Na+-K+-ATPase (NKA) is essential in maintaining cell permeability, reserving potential energy, and preventing cellular edema. Nevertheless, how NKA expression is altered and regulated in chronic rhinosinusitis with nasal polyps (CRSwNPs) remain uncertain. Therefore, the present study aimed to explore the expression and regulation of NKA in CRSwNP.

METHODS

NKA immunolabeling was assessed by the immunohistochemistry method, NKA protein levels were detected with the Western blotting method, and mRNA levels of NKA and aquaporin-5 (AQP5) were assayed by real-time PCR in nasal tissues from CRSwNP and control subjects. The co-localization of NKA with inflammatory cells was evaluated by immunofluorescence staining. In addition, human nasal epithelial cells (HNECs) were cultured and stimulated using various stimulators to evaluate the regulation of NKA.

RESULTS

We found significantly decreased NKA positive cells, NKA protein levels, and mRNA levels of NKA and AQP5 in nasal tissues from CRSwNP patients compared to control subjects, especially in eosinophilic CRSwNP. Furthermore, NKA mRNA levels in HNECs were downregulated by staphylococcal enterotoxin B (SEB), lipopolysaccharides (LPSs), inflammatory cytokine (IFN)-γ, IL-4, IL-13, and IL-1β.

CONCLUSION

NKA and AQP5 expressions were decreased in CRSwNP. NKA in HNECs could be suppressed by SEB, LPS, IFN-γ, IL-4, IL-13, and IL-1β. Impairment of NKA may contribute to the genesis and development of CRSwNP via inducing AQP5 downregulation and edema.

Infection outcome needs two to tango: human host and the pathogen

Infectious diseases are potential drivers for human evolution, through a complex, continuous and dynamic interaction between the host and the pathogen/s. It is this dynamic interaction that contributes toward the clinical outcome of a pathogenic disease. These are modulated by contributions from the human genetic variants, transcriptional response (including noncoding RNA) and the pathogen’s genome architecture. Modern genomic tools and techniques have been crucial for the detection and genomic characterization of pathogens with respect to the emerging infectious diseases. Aided by next-generation sequencing (NGS), risk stratification of host population/s allows for the identification of susceptible subgroups and better disease management. Nevertheless, many challenges to a general understanding of host–pathogen interactions remain. In this review, we elucidate how a better understanding of the human host-pathogen interplay can substantially enhance, and in turn benefit from, current and future applications of multi-omics based approaches in infectious and rare diseases. This includes the RNA-level response, which modulates the disease severity and outcome. The need to understand the role of human genetic variants in disease severity and clinical outcome has been further highlighted during the Coronavirus disease 2019 (COVID-19) pandemic. This would enhance and contribute toward our future pandemic preparedness.

The Potential Role of Bacteriophages in the Treatment of Recalcitrant Chronic Rhinosinusitis

Chronic rhinosinusitis is a common condition affecting 5-12% of the general population worldwide. In a limited number of cases, the disease is recalcitrant to medical and surgical interventions, causing a major impact on physical, social and emotional well-being and increasing pressure on healthcare systems. Biofilm formation and dysbiosis caused by Staphylococcus aureus and Pseudomonas aeruginosa play a role in the pathogenesis of recalcitrant chronic rhinosinusitis. In these cases, a promising treatment alternative is the application of bacteriophages, which are viruses that infect and lyse bacteria. In this review, we appraise the evidence for the use of bacteriophages in the treatment of recalcitrant chronic rhinosinusitis. Additionally, (dis)advantages of bacteriophages and considerations for implementation of phage therapy in otorhinolaryngology practice will be discussed.

Th2 inflammatory responses in the development of nasal polyps and chronic rhinosinusitis

PURPOSE OF REVIEW

Pathogenesis of nasal polyp has been largely studied based on innate and adaptive immunity of sinonasal mucosa. So far, various factors have been identified that trigger an inflammatory response in the pathogenesis of nasal polyps. In this review, we summarized recently updated information in the understanding of mechanisms in the development of chronic rhinosinusitis with nasal polyp (CRSwNP) focusing on Th2 inflammation.

RECENT FINDINGS

Endotype of CRSwNP presented mainly Th2-skewed inflammation, and it has been associated with refractoriness and comorbidities. Staphylococcus aureus can drive Th2 inflammation by producing enterotoxins and serine protease-like protein. Moreover, S. aureus directly affected mucosal barrier function and enhanced Th2 cytokine production by fast induction of epithelial-derived innate cytokines. Epithelial-derived innate cytokines, including TSLP, IL-25, and IL-33, promote Th2 responses via the development of innate lymphoid cells. Mast cell expresses IL-5, IL-13, and periostin, and it plays a role in the pathogenesis of nasal polyps through orchestrating eosinophil infiltration. Formation of eosinophil extracellular traps and Charcot-Leyden crystals is strongly associated with disease severity and viscous mucus plug production. Therefore, it needs to be investigated mechanistically. The role of neutrophils in Th2 inflammation has been poorly understood but appears to enhance Th2 inflammation and make it more resistant to steroid therapy.

SUMMARY

There is growing evidence of the role of S. aureus in innate and adaptive immunity, which contribute to Th2 inflammation in CRSwNP. Innate immunity, including epithelial-derived cytokines, plays a crucial role in the development of CRSwNP by inducing various pathways and need to be investigated more as Th2-targeted biomarkers. Recently, the role of neutrophilic inflammation in Th2 inflammation has started to be studied but still remains unclear.

What is the contribution of IgE to nasal polyposis?

Taking a novel approach, this narrative review collates knowledge about nasal polyposis and the biological functions of IgE in several diseases (allergic rhinitis, allergic asthma, nonsteroidal anti-inflammatory drugs-exacerbated respiratory disease, and chronic spontaneous urticaria) to consider which IgE-mediated mechanisms are relevant to nasal polyposis pathology. A type 2 eosinophil-dominated inflammatory signature is typical in nasal polyp tissue of European patients with nasal polyposis, with a shift toward this endotype observed in Asian populations in recent years. Elevated polyclonal IgE is present in the nasal tissue of patients with and without allergy. It is derived from many different B-cell clones and, importantly, is functional (proinflammatory). Staphylococcus aureus enterotoxins are thought to act as superantigens, inducing production of polyclonal IgE via B-cell and T-cell activation, and triggering release of inflammatory mediators. In some patients, exposure to antigens/triggers leads to production of high levels of antigen-specific IgE, which mediates cross-linking of the high-affinity IgE receptor on various cells, causing release of inflammatory mediators. The efficacy of omalizumab confirms IgE as an important inflammatory mediator in nasal polyposis. By blocking IgE, omalizumab targets the T2 inflammation in nasal polyposis, reduces nasal polyp score and improves symptoms.

Monoclonal Antibodies and Airway Diseases

Monoclonal antibodies, biologics, are a relatively new treatment option for severe chronic airway diseases, asthma, allergic rhinitis, and chronic rhinosinusitis (CRS). In this review, we focus on the physiological and pathomechanisms of monoclonal antibodies, and we present recent study results regarding their use as a therapeutic option against severe airway diseases. Airway mucosa acts as a relative barrier, modulating antigenic stimulation and responding to environmental pathogen exposure with a specific, self-limited response. In severe asthma and/or CRS, genome-environmental interactions lead to dysbiosis, aggravated inflammation, and disease. In healthy conditions, single or combined type 1, 2, and 3 immunological response pathways are invoked, generating cytokine, chemokine, innate cellular and T helper (Th) responses to eliminate viruses, helminths, and extracellular bacteria/fungi, correspondingly. Although the pathomechanisms are not fully known, the majority of severe airway diseases are related to type 2 high inflammation. Type 2 cytokines interleukins (IL) 4, 5, and 13, are orchestrated by innate lymphoid cell (ILC) and Th subsets leading to eosinophilia, immunoglobulin E (IgE) responses, and permanently impaired airway damage. Monoclonal antibodies can bind or block key parts of these inflammatory pathways, resulting in less inflammation and improved disease control.

The Role of Biologics in Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common and heterogeneous inflammatory disease of the upper respiratory tract. This article provides expert opinion and points of view from both allergists and rhinologists who specialize in CRSwNP. Despite the potential value of biomarker-based endotyping to provide guidance regarding optimal care and treatment choices for patients with CRSwNP, current practice is largely not biomarker-based. In general, there is agreement that for patients with symptomatic CRSwNP who have failed a trial of a course of at least 3 months of intranasal steroids and a short course of oral corticosteroids, a surgical intervention will often be the next treatment of choice. Biologics may be considered before an initial surgery in patients with comorbid severe asthma and in those for whom surgery is less available, refused by the patient, or likely to be associated with a higher-than-average complication rate. Biologic use immediately following surgery may be considered in patients who have a history of nasal polyp recurrence within 12 months of a prior surgery. For many patients with recalcitrant disease, a combination of sinus surgery and use of a biologic that is targeted to their precise endotype may be the optimal treatment strategy, though which surgical approach and which biologics are best for each patient are debates that remain ongoing.

Staphylococcus aureus and its IgE-inducing enterotoxins in asthma: current knowledge

While immunoglobulin (Ig) E is a prominent biomarker for early-onset, its levels are often elevated in non-allergic late-onset asthma. However, the pattern of IgE expression in the latter is mostly polyclonal, with specific IgEs low or below detection level albeit with an increased total IgE. In late-onset severe asthma patients, specific IgE to Staphylococcal enterotoxins (se-IgE) can frequently be detected in serum, and has been associated with asthma, with severe asthma defined by hospitalisations, oral steroid use and decrease in lung function. Recently, se-IgE was demonstrated to even predict the development into severe asthma with exacerbations over the next decade. Staphylococcus aureus manipulates the airway mucosal immunology at various levels via its proteins, including superantigens, serine-protease-like proteins (Spls), or protein A (SpA) and possibly others. Release of IL-33 from respiratory epithelium and activation of innate lymphoid cells (ILCs) via its receptor ST2, type 2 cytokine release from those ILCs and T helper (Th) 2 cells, mast cell degranulation, massive local B-cell activation and IgE formation, and finally eosinophil attraction with consequent release of extracellular traps, adding to the epithelial damage and contributing to disease persistence via formation of Charcot-Leyden crystals are the most prominent hallmarks of the manipulation of the mucosal immunity by S. aureus In summary, S. aureus claims a prominent role in the orchestration of severe airway inflammation and in current and future disease severity. In this review, we discuss current knowledge in this field and outline the needs for future research to fully understand the impact of S. aureus and its proteins on asthma.

Pre-treatment with IL2 gene therapy alleviates Staphylococcus aureus arthritis in mice

BACKGROUND

Staphylococcus aureus (S. aureus) arthritis is one of the most detrimental joint diseases known and leads to severe joint destruction within days. We hypothesized that the provision of auxiliary immunoregulation via an expanded compartment of T regulatory cells (Tregs) could dampen detrimental aspects of the host immune response whilst preserving its protective nature. Administration of low-dose interleukin 2 (IL2) preferentially expands Tregs, and is being studied as a treatment choice in several autoimmune conditions. We aimed to evaluate the role of IL2 and Tregs in septic arthritis using a well-established mouse model of haematogenously spred S. aureus arthritis.

METHODS

C57BL/6 or NMRI mice we intravenously (iv) injected with a defined dose of S. aureus LS-1 or Newman and the role of IL2 and Tregs were assessed by the following approaches: IL2 was endogenously delivered by intraperitoneal injection of a recombinant adeno-associated virus vector (rAAV) before iv S. aureus inoculation; Tregs were depleted before and during S. aureus arthritis using antiCD25 antibodies; Tregs were adoptively transferred before induction of S. aureus arthritis and finally, recombinant IL2 was used as a treatment starting day 3 after S. aureus injection. Studied outcomes included survival, weight change, bacterial clearance, and joint damage.

RESULTS

Expansion of Tregs induced by IL2 gene therapy prior to disease onset does not compromise host resistance to S. aureus infection, as the increased proportions of Tregs reduced the arthritis severity as well as the systemic inflammatory response, while simultaneously preserving the host's ability to clear the infection.

CONCLUSIONS

Pre-treatment with IL2 gene therapy dampens detrimental immune responses but preserves appropriate host defense, which alleviates S. aureus septic arthritis in a mouse model.

Anterior Nares Diversity and Pathobionts Represent Sinus Microbiome in Chronic Rhinosinusitis

It is generally believed that the microbiome plays a role in the pathophysiology of chronic rhinosinusitis (CRS), though its exact contribution to disease development and severity remains unclear. Here, samples were collected from the anterior nares, nasopharynx, and maxillary and ethmoid sinuses of 190 CRS patients and from the anterior nares and nasopharynx of 100 controls. Microbial communities were analyzed by Illumina sequencing of the V4 region of 16S rRNA. The phenotype and patient characteristics were documented, and several serum inflammatory markers were measured. Our data indicate a rather strong continuity for the microbiome in the different upper respiratory tract (URT) niches in CRS patients, with the microbiome in the anterior nares being most similar to the sinus microbiome. Bacterial diversity was reduced in CRS patients without nasal polyps compared to that in the controls but not in CRS patients with nasal polyps. Statistically significant differences in the presence/absence or relative abundance of several taxa were found between the CRS patients and the healthy controls. Of these, Dolosigranulum pigrum was clearly more associated with URT samples from healthy subjects, while the Corynebacterium tuberculostearicum, Haemophilus influenzae/H. aegyptius, and Staphylococcus taxa were found to be potential pathobionts in CRS patients. However, CRS versus health as a predictor explained only 1 to 2% of the variance in the microbiome profiles in an adonis model. A history of functional endoscopic sinus surgery, age, and sex also showed a minor association. This study thus indicates that functional studies on the potential beneficial versus pathogenic activity of the different indicator taxa found here are needed to further understand the pathology of CRS and its different phenotypes. (This study has been registered at ClinicalTrials.gov under identifier NCT02933983.)IMPORTANCE There is a clear need to better understand the pathology and specific microbiome features in chronic rhinosinusitis patients, but little is known about the bacterial topography and continuity between the different niches of the upper respiratory tract. Our work showed that the anterior nares could be an important reservoir for potential sinus pathobionts. This has implications for the diagnosis, prevention, and treatment of CRS. In addition, we found a potential pathogenic role for the Corynebacterium tuberculostearicum, Haemophilus influenzae/H. aegyptius, and Staphylococcus taxa and a potential beneficial role for Dolosigranulum Finally, a decreased microbiome diversity was observed in patients with chronic rhinosinusitis without nasal polyps compared to that in healthy controls but not in chronic rhinosinusitis patients with nasal polyps. This suggests a potential role for the microbiome in disease development or progression of mainly this phenotype.

Eosinophilic chronic rhinosinusitis

Eosinophilic chronic rhinosinusitis (ECRS) is a subgroup of chronic rhinosinusitis with nasal polyps (CRSwNP), which is associated with severe eosinophilic infiltration and intractable. Its symptoms include dysosmia, nasal obstruction, and visous nasal discharge. The cause of ECRS is not clear, although it is thought that Staphylococcus aureus and its enterotoxins are involved in stimulating the Th2 system to promote IgE production and eosinophil infiltration through various pathways. While, the coagulation system is activated and the fibrinolytic system is suppressed, leading to deposition of fibrinous networks in nasal polyps. Therefore, a fibrin-degrading agent could be a new treatment for ECRS. Genetic analysis of nasal polyp cells using next-generation sequencing has identified some of the factors involved in ECRS, including periostin, which can be used as a biomarker of this condition. A protease inhibitor could be a therapeutic agent for ECRS. Regarding the role of eosinophils, many researchers have been interested in the mechanism of ETosis. However, the mechanism leading to development of nasal polyps is unknown. In Japan (as well as in East Asia), the incidence of non-ECRS is decreasing and that of ECRS is increasing, but the reason is also unknown. Thanks to the development of biologics therapy, it is thought that there will be a shift to precision medicine in the future.

Sensitisation to staphylococcal enterotoxins and asthma severity: a longitudinal study in the EGEA cohort

INTRODUCTION

Evidence is accumulating that Staphylococcus aureus plays an important role as disease modifier in upper and lower airway diseases. Sensitisation to S. aureus enterotoxins (SEs) was associated with an increased risk of severe asthma in previous cross-sectional studies, but evidence from longitudinal studies is lacking. We aimed to assess associations between SE-sensitisation and the subsequent risk for asthma severity and exacerbations.

METHODS

This is a nested case-control study from the 20-year Epidemiological Study of the Genetics and Environment of Asthma (EGEA) cohort, including 225 adults (75 without asthma, 76 with mild asthma and 74 with severe asthma) in EGEA2 (2003-2007). For 173 of these individuals, SE-sensitisation was measured on samples collected 11 years earlier (EGEA1). Cross-sectional associations were conducted for EGEA1 and EGEA2. Longitudinal analyses estimated the association between SE-sensitisation in EGEA1 and the risk of severe asthma and asthma exacerbations assessed in the follow-up. Models were adjusted for sex, age, smoking, parental asthma/allergy and skin-prick test to house dust mite.

RESULTS

SE-sensitisation varied between 39% in controls to 58% and 76% in mild and severe asthma, respectively, in EGEA1. An adjusted cross-sectional association showed that SE-sensitisation was associated with an increased risk of severe, but not for mild asthma. SE-sensitisation in EGEA1 was associated with severe asthma (adjusted OR 2.69, 95% CI 1.18-6.15) and asthma exacerbations (adjusted OR 4.59, 95% CI 1.40-15.07) assessed 10-20 years later.

CONCLUSION

For the first time, this study shows that being sensitised to SEs is associated with an increased subsequent risk of severe asthma and asthma exacerbations.