COX/PGE(2) axis critically regulates effects of LPS on eosinophilia-associated cytokine production in nasal polyps

Pathogenesis-based application of biologics for chronic rhinosinusitis: Current and future perspectives

Chronic rhinosinusitis (CRS) is heterogeneous and contains diverse pathogenesis including type 1, type 2, and/or type 3 inflammation. For severe type 2 CRS especially CRS with nasal polyps (CRSwNP), biologics that target inflammatory molecules have recently been applied along with further changes in the treatment algorithm for CRS. Currently, a completed phase 3 clinical trial for biologics for severe CRSwNP with inadequate response to surgery and/or intranasal corticosteroids, including omalizumab (anti-IgE), mepolizumab (anti-IL-5), benralizumab (anti-IL-5Rα), and dupilumab (anti-IL-4Rα), have all shown efficacy. Similar phase 3 clinical trials for tezepelumab (anti-TSLP) and etokimab (anti-IL-33) are now underway and completed, respectively. Further studies need to evaluate how to optimally and cost-effectively use biologics for CRS and determine if any biomarkers are indicative of which biologics should be administered. A definition of complete and/or clinical remission of CRS is also needed to determine when to reduce or discontinue biologics. In addition, more precise basic research on CRS, such as endotyping and genotyping, will need to be undertaken in order to determine novel targets for biologics.

Middle meatus microbiome in patients with eosinophilic chronic rhinosinusitis in a Japanese population

BACKGROUND

Chronic rhinosinusitis (CRS) is a common chronic inflammatory disease and is subdivided into eosinophilic and noneosinophilic forms. There are few reports investigating the nasal microbiome and its pathological functions in patients with CRS.

OBJECTIVE

We sought to analyze factors contributing to variations of the nasal microbiome in CRS, and on the basis of these factors, to elucidate whether the bacterial metabolites were related to the pathogenesis.

METHODS

Nasal swabs were collected, and the V3 to V4 variable region of the 16S ribosomal RNA gene was amplified and sequenced. Factors contributing to variations of the nasal microbiome in patients with CRS were compared. The most influential factor was whether CRS was eosinophilic, and we compared α- and β-diversity, bacterial species, and predictive bacterial functions between the 2 patient groups. In addition, the metabolites of the key bacteria were extracted, and we evaluated the predicted bacterial functions in airway epithelial cells.

RESULTS

In total, 110 patients with CRS and 33 control subjects were enrolled. On the basis of the factors of variation, it was found that patients with eosinophilic CRS (n = 65) had different microbiomes with weighted UniFrac β-diversity and lower α-diversity compared with those with noneosinophilic CRS (n = 45). A higher abundance of Fusobacterium nucleatum and an increased LPS pathway were observed in patients with noneosinophilic CRS compared with those with eosinophilic CRS. In airway epithelial cells, LPS derived from F nucleatum suppressed the expression levels of ALOX15 induced by TH2 cytokines.

CONCLUSIONS

The differences in the nasal microbiome may play a key role in the pathophysiology of CRS.

Macroarray expression analysis of cytokines and prostaglandin metabolism-related genes in chronic rhinosinusitis

Background

Chronic rhinosinusitis (CRS) can be divided into endotypes by functional or pathophysiologic findings.

Objective

The aim of this study was to analyze the expression of cytokines, prostaglandin (PG) synthases, and their receptors related to the pathogenesis of CRS, especially those contributing to nasal polyp (NP) formation.

Methods

NPs and uncinate tissue (UT) samples were collected from 90 patients who underwent endoscopic sinus surgery. They included 75 patients with CRS (including 45 with eosinophilic CRS [eCRS] and 30 with non-eCRS) and 15 patients without CRS. A total of 30 genes were selected for our original DNA array plate to analyze the levels of expression of 10 cytokines (IFN-γ, IL-4, IL-5, IL-10, IL-13, IL-17A, IL-22, IL-25, IL-33, and TSLP), 4 prostaglandin synthases (prostaglandin D2 [PGD2] synthase, prostaglandin E2 synthase, COX-1, and COX-2), and their 16 receptors. Clustering analysis was performed according to the expression results, and clinical findings of patients from each cluster were investigated.

Results

The samples could be divided into 3 clusters. Cluster 1 showed elevated levels of expression of IL4, IL5, IL13, TSLP, IL1RL1 (ST2 [an IL-33 receptor]), HPGDS, and GPR44 (CRTH2, a PGD2 receptor); cluster 2 showed elevated levels of expression of IL17A and PTGES; and cluster 3 showed an elevated level of expression of IL25. Regarding clinical features, the main characteristics of each cluster were as follows: NPs from patients with eCRS for cluster 1, NPs and/or UT samples from patients with non-eCRS for cluster 2, and UTs from patients with non-CRS for cluster 3.

Conclusion

The results suggest that there are associations between type 2 inflammation/PGD2 and eCRS and also between type 3 inflammation/prostaglandin E2 and non-eCRS.

Serum metabolomics profiling of improved metabolic syndrome is characterized by decreased pro-inflammatory biomarkers: A longitudinal study in Chinese male adults

Metabolic syndrome (MetS) is a serious global health concern. The objective of this study is to dynamically investigate the changes of metabolic profiles and metabolites in Chinese male MetS subjects after an 18 months diet and exercise intervention. Fifty male MetS patients defined according to International Diabetes Federation 2005 guidelines were subjected to diet and exercise counseling for 18 months. Serum samples were taken at baseline, 12 months, and 18 months, respectively, for clinical evaluation and metabolomics analyses. Diet and exercise intervention for 18 months achieved significant improvements in the metabolic profiles of all participants. Nineteen subjects (38.0%) exhibited MetS remission at the end of the study. A total of 812 relative features were characterized and 61 were successfully identified. Furthermore, 17 differential metabolites were of significance at both time points (baseline-12 months, baseline-18 months) and presented nonlinear trends through time. Eight metabolites (47.1%) were predominantly converged to inflammation and oxidative stress. Pro-inflammatory biomarkers were remarkably decreased after 18 months of intervention, and prostaglandin E2, neuroprotectin D1, and taxiphyllin in combination were firstly found to demonstrate a fair discriminative power (area under curve = 0.911) to predict the improvement of MetS undergone diet and exercise intervention. The significant shift of metabolomic profiling after 18 months of lifestyle counseling provide a novel insight and reveal that earlier inflammation control may be of potential benefit in MetS management.

Bcl2 like protine-12 (Bcl2L12) facilitates experimental airway allergic inflammation by inducing autocrine eotaxin in eosinophils

BACKGROUND

The pathogenesis of airway allergic disorders (AAD) needs to be further investigated. Eosinophils (Eos) are the canonical effector cells in AAD attacks. Bcl2 like protein-12 (Bcl2L12) is an apoptosis inhibitor and an immune regulator. Eos have the defects of apoptosis. This study aims to investigate the role of Bcl2L12 in the AAD pathogenesis by regulating Eo activities.

METHODS

Human nasal lavage fluids (NLF) and mouse bronchoalveolar lavage fluids (BALF) was collected. Eos in NLF and BALF were analyzed by flow cytometry. A murine AAD model was developed with ovalbumin as a specific antigen.

RESULTS

We found that Eos isolated from NLF or BALF of AAD subjects expressed high levels of Bcl2L12 and showed defects of apoptosis. The Bcl2L12 expression in Eos was positively correlated with the AAD response. High lipopolysaccharide levels were detected in the AAD airways, that promoted the Bcl2L12 expression in Eos. Bcl2L12 mediated the LPS-induced autocrine eotaxin 1 expression in Eos through activating the MAPK p38/STAT6/NF-κB signal pathway. Depletion of Bcl2L12 in Eos suppressed experimental AAD in mice.

CONCLUSIONS

AAD Eos express high levels of Bcl2L12, the latter is associated with AAD response by regulating the autocrine eotaxin 1 in Eos. Depletion of Bcl2L12 in Eos attenuates experimental AAD, suggesting that to suppress the Bcl2L12 Eos has the translational potential in the treatment of AAD.

Increased lipopolysaccharide content is positively correlated with glucocorticoid receptor-beta expression in chronic rhinosinusitis with nasal polyps

Introduction

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common and frequently occurring disease of the upper respiratory tract. The nasal instillation of the Gram‐negative (G⁻) bacterial product lipopolysaccharide (LPS) can induce not only acute sinusitis but also the development of CRSwNP in animal models. Nevertheless, the expression and distribution of LPS in patients with CRSwNP have not been investigated. And the study was to investigate the expression of LPS and its relationship with glucocorticoid receptors (GRs) in CRSwNP.

Methods

Multiple methods, including bacterial culture and immunohistochemistry, were used to detect and analyze nasal bacteria, plasma LPS content, and the levels of LPS and GR‐α/β, cluster of differentiation 68 (CD68), and myeloperoxidase (MPO) expression, as well as their relationship in CRSwNP.

Results

The number of G⁻ bacteria and Escherichia coli (E. coli) was not significantly different between CRSwNP subjects and the controls. However, the positive rate of LPS was much higher than that of E. coli in CRSwNP subjects and was significantly higher in noneosinophilic CRSwNP subjects than in eosinophilic CRSwNP subjects. Moreover, the LPS levels were positively correlated with GR‐β but not GR‐α expression in CRSwNP. Immunofluorescence assays showed that LPS was mainly detected in CD68⁺ macrophages and MPO⁺ neutrophils, in addition to histiocytes, in CRSwNP.

Conclusions

Persistent LPS in CRSwNP can lead to unresolved mucosal inflammation, eventually leading to tissue remodeling and the development of CRSwNP. Our findings suggest that increased LPS content and possible resistance to glucocorticoids may be one of the important pathogenic mechanisms of G⁻ bacteria in CRSwNP.

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.

COX-1 mediates IL-33-induced extracellular signal-regulated kinase activation in mast cells: Implications for aspirin sensitivity

BACKGROUND

Classical FcεRI-induced mast cell (MC) activation causes synthesis of arachidonic acid (AA)-derived eicosanoids (leukotriene [LT] C₄, prostaglandin [PG] D₂, and thromboxane A₂), which mediate vascular leak, bronchoconstriction, and effector cell chemotaxis. Little is known about the significance and regulation of eicosanoid generation in response to nonclassical MC activation mechanisms.

OBJECTIVES

We sought to determine the regulation and significance of MC-derived eicosanoids synthesized in response to IL-33, a cytokine critical to innate type 2 immunity.

METHODS

We used an ex vivo model of mouse bone marrow-derived mast cells and an IL-33-dependent in vivo model of aspirin-exacerbated respiratory disease (AERD).

RESULTS

IL-33 potently liberates AA and elicits LTC₄, PGD₂, and thromboxane A₂ production by bone marrow-derived mast cells. Unexpectedly, the constitutive function of COX-1 is required for IL-33 to activate group IVa cytosolic phospholipase A₂ with consequent AA release for synthesis of all eicosanoids, including CysLTs. In contrast, COX-1 was dispensable for FcεRI-driven CysLT production. Inhibition of COX-1 prevented IL-33-induced phosphorylation of extracellular signal-related kinase, an upstream effector of cytosolic phospholipase A₂, which was restored by exogenous PGH₂, implying that the effects of COX-1 required its catalytic function. Administration of a COX-1-selective antagonist to mice completely prevented the generation of both PGD₂ and LTC₄ in a model of AERD in which MC activation is IL-33 driven.

CONCLUSIONS

MC-intrinsic COX-1 amplifies IL-33-induced activation in the setting of innate type 2 immunity and might help explain the phenomenon of therapeutic desensitization to aspirin by nonselective COX inhibitors in patients with AERD.

Association between impaired IL-10 production following exposure to Staphylococcus aureus enterotoxin B and disease severity in eosinophilic chronic rhinosinusitis

BACKGROUND

IL-10 is a major anti-inflammatory cytokine that prevents inflammation-mediated tissue damage. We characterized the production of IL-10 by sinonasal tissue cells following exposure to Staphylococcus aureus enterotoxin B (SEB), which elicits cellular responses and is associated with the pathogenesis of eosinophilic chronic rhinosinusitis (ECRS).

METHODS

Dispersed nasal polyp (NP) cells and uncinate tissue (UT) cells were prepared from patients with CRS with and without NP, respectively. Cells were incubated with SEB, and then the levels of IL-10 in the cell supernatants were determined. The effect of neutralizing IL-10 on SEB-induced IL-5, IL-13, IFN-γ, and IL-17A production was examined. Expression of IL-10 in NPs was also determined.

RESULTS

IL-10 was expressed in infiltrating inflammatory cells in NPs. NP cells, especially non-adherent NP cells, produced substantial amounts of IL-10 in response to SEB. Although baseline production of IL-10 was significantly higher in NP cells than UT cells, the degree of IL-10 response to SEB was not significantly different between the cell types. The degree of IL-10 production was negatively correlated with the degree of eosinophilia both in tissues and peripheral blood whereas positively correlated with the 1-s forced expiratory volume/forced vital capacity ratio. Patients with severe ECRS displayed a significant decrease in IL-10 production compared with those with non-ECRS. IL-10 neutralization significantly augmented SEB-induced IL-13 and IFN-γ production by NP cells.

CONCLUSIONS

Impaired IL-10 production in response to SEB in NP may exacerbate the pathophysiology of ECRS including eosinophilia and lower airway obstruction.

IL-22/IL-22R1 signaling regulates the pathophysiology of chronic rhinosinusitis with nasal polyps via alteration of MUC1 expression

BACKGROUND

IL-22 is an IL-10-family cytokine that regulates chronic inflammation. We investigated the role of IL-22 and its receptor, IL-22R1, in the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP).

METHODS

IL-22 and IL-22R1 protein and mRNA expression in NP and in uncinate tissues (UT) from CRS and non-CRS patients was examined using immunohistochemistry and real-time PCR, respectively. Dispersed NP and UT cells were cultured with the Staphylococcus aureus exotoxins, staphylococcal enterotoxin B and alpha-toxin, following which exotoxin-induced IL-22 levels and their association with clinicopathological factors were analyzed. Effects of IL-22 on MUC1 expression and cytokine release in NP cells were also determined.

RESULTS

IL-22 and IL-22R1 in NP were mainly expressed in infiltrating inflammatory cells and in epithelial cells, respectively. IL-22 mRNA levels in NP were significantly higher than those in UTs from non-CRS patients whereas IL-22R1 levels were conversely lower in NPs. NP cells produced substantial amounts of IL-22 in response to exotoxins. Exotoxin-induced IL-22 production by NP cells significantly and negatively correlated with the degree of local eosinophilia and postoperative computed tomography (CT) score, whereas conversely it positively correlated with the forced expiratory volume in 1s (FEV1)/forced vital capacity (FVC) ratio. IL-22 significantly enhanced MUC1 mRNA expression in NP cells. IL-22-induced MUC1 mRNA levels were significantly and positively correlated with IL-22R1 mRNA levels in NPs.

CONCLUSIONS

These data suggest that imbalance of IL-22/IL-22R1 signaling regulates the pathogenesis of CRSwNP, including local eosinophilia, via alteration of MUC1 expression.

Role of Interleukin-10 on Nasal Polypogenesis in Patients with Chronic Rhinosinusitis with Nasal Polyps

Background and Objectives

Interleukin 10 (IL-10) is a potent anti-inflammatory cytokine. The dysregulation of IL-10 is associated with an enhanced immunopathologic response to infection, as well as with an increased risk for developing numerous autoimmune diseases. In this study, we investigated IL-10 expression in chronic rhinosinusitis with nasal polyps (CRSwNP) and assessed the possible role of IL-10 in the pathogenesis of CRSwNP.

Materials and Methods

Thirty-five patients with CRSwNP, 12 patients with chronic rhinosinusitis without NP (CRSsNP) and 10 control subjects were enrolled in this study. NP tissues and uncinated tissues (UT) were collected for analysis. Dispersed NP cells (DNPCs) were cultured in the presence or absence of IL-25 and IL-10, and a flow cytometric assay was performed to identify the constitutive cell populations of the DNPCs. Murine NP (n = 18) models were used for the in vivo experiments. Real-time PCR, immunohistochemistry, western blotting analysis and ELISA were performed to measure the expression levels of the selected inflammatory cytokines and inflammation-associated molecules.

Results

The mRNA expression levels of IL-10, IL-5, IL-17A, IL-25 and interferon gamma (IFN-γ) were significantly higher in the NP tissues than in the UT tissues. Strong positive correlations were observed between IL-10 and a variety of inflammatory cytokines (IL-5, IL-17A, IL-25, IFN-γ) and inflammation-associated molecules (B-cell activating factor; BAFF, CD19). Other than the IL-25 to IL-10 ratio, the expression ratios of the other measured inflammatory cytokines to IL-10 were significantly lower in the CRSwNP group than in the CRSsNP or control groups. Administrating IL-25 into the cultured DNPCs significantly increased the production of IL-10, but administrating IL-10 had no effect on the production of IL-25.

Conclusion

Increased expression of IL-10, IL-10 related inflammatory cytokine, and IL-10 related B cell activation indicated that IL-10, a potent anti-inflammatory cytokine, has a pivotal role in the pathogenesis of CRSwNPs.

Regulatory effect of TLR3 signaling on staphylococcal enterotoxin-induced IL-5, IL-13, IL-17A and IFN-γ production in chronic rhinosinusitis with nasal polyps

BACKGROUND

Toll-like receptor 3 (TLR3) is expressed in upper airways, however, little is known regarding whether Toll-like receptor 3 (TLR3) signals exert a regulatory effect on the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP), especially on eosinophilic inflammation. We sought to investigate the effect of Poly(IC), the ligand for TLR3, on cytokine production by dispersed nasal polyp cells (DNPCs).

METHODS

DNPCs were pretreated with or without Poly(IC), and were then cultured in the presence or absence of staphylococcal enterotoxin B (SEB), following which the levels of IL-5, IL-10, IL-13, IL-17A and interferon (IFN)-γ in the supernatant were measured. To determine the involvement of IL-10 and cyclooxygenase in Poly(IC)-mediated signaling, DNPCs were treated with anti-IL-10 monoclonal antibody and diclofenac, the cyclooxygenase inhibitor, respectively. Poly(IC)-induced prostaglandin E2 (PGE2) production was also determined.

RESULTS

Exposure to Poly(IC) induced a significant production of IL-10, but not of IL-5, IL-13, IL-17A or IFN-γ by DNPCs. Pretreatment with Poly(IC) dose-dependently inhibited SEB-induced IL-5, IL-13 and IL-17A, but not IFN-γ production. Neutralization of IL-10 significantly abrogated the inhibitory effect of Poly(IC). Treatment with diclofenac also abrogated the inhibitory effect of Poly(IC) on SEB-induced IL-5 and IL-13 production. However, unlike exposure of diclofenac-treated DNPCs to lipopolysaccharide, the ligand for TLR4, exposure of these cells to Poly(IC) did not enhance IL-5 or IL-13 production. Poly(IC) did not significantly increase PGE2 production by DNPCs.

CONCLUSIONS

These results suggest that TLR3 signaling regulates eosinophilia-associated cytokine production in CRSwNP, at least in part, via IL-10 production.

Picfeltarraenin IA inhibits lipopolysaccharide-induced inflammatory cytokine production by the nuclear factor-κB pathway in human pulmonary epithelial A549 cells

The present study aimed to investigate the effect of picfeltarraenin IA (IA) on respiratory inflammation by analyzing its effect on interleukin (IL)-8 and prostaglandin E2 (PGE2) production. The expression of cyclooxygenase 2 (COX2) in human pulmonary adenocarcinoma epithelial A549 cells in culture was also examined. Human pulmonary epithelial A549 cells and the human monocytic leukemia THP-1 cell line were used in the current study. Cell viability was measured using a methylthiazol tetrazolium assay. The production of IL-8 and PGE2 was investigated using an enzyme-linked immunosorbent assay. The expression of COX2 and nuclear factor-κB (NF-κB)-p65 was examined using western blot analysis. Treatment with lipopolysaccharide (LPS; 10 µg/ml) resulted in the increased production of IL-8 and PGE2, and the increased expression of COX2 in the A549 cells. Furthermore, IA (0.1-10 µmol/l) significantly inhibited PGE2 production and COX2 expression in cells with LPS-induced IL-8, in a concentration-dependent manner. The results suggested that IA downregulates LPS-induced COX2 expression, and inhibits IL-8 and PGE2 production in pulmonary epithelial cells. Additionally, IA was observed to suppress the expression of COX2 in THP-1 cells, and also to regulate the expression of COX2 via the NF-κB pathway in the A549 cells, but not in the THP-1 cells. These results indicate that IA regulates LPS-induced cytokine release in A549 cells via the NF-κB pathway.

Phospholipase A2-dependent Release of Inflammatory Cytokines by Superantigen-Stimulated Nasal Polyps of Patients with Chronic Rhinosinusitis

Background

Chronic rhinosinusitis (CRS) is an inflammatory/allergic disease with unclear pathophysiology, but it has been linked to an imbalance in the production of eicosanoids, which are metabolites of arachidonic acid, and results from phospholipids hydrolysis by phospholipase A2 (PLA2). As of yet, the role of PLA2 in CRS has hardly been studied, except for a report that group II PLA2 expression is elevated in interleukin (IL) 1β or tumor necrosis factor α-stimulated CRS nasal tissues with and without polyps. The PLA2 families include extracellular (secretory) and intracellular isoforms, which are involved in the regulation of inflammatory processes in different ways. Here we comprehensively investigated the expression of PLA2s, particularly those reported to be involved in respiratory disorders, in superantigen (SAE)-stimulated nasal polyps from patients with CRS with polyps, and determined their role in inflammatory cytokine production by inhibition of PLA2 expression.

Methods

The release of IL-5, IL-13, IL-17, and interferon γ by nasal polyps dispersed cells (NPDC) was determined concomitantly with PLA2 messenger RNA expression, under SAE stimulation, with or without dexamethasone, as a regulator of PLA2 expression.

Results

Stimulation of NPDCs by SAE-induced cytokine secretion with enhanced expression of several secretory PLA2 and Ca2+-independent PLA2, while suppressing cytosolic PLA2 expression. All these were reverted to the level of unstimulated NPDCs on treatment with dexamethasone.

Conclusion

This study further supports the key role of secretory PLA2 in the pathophysiology of respiratory disorders and presents secretory PLA2 inhibition as a therapeutic strategy for the treatment of CRS and airway pathologies in general.

Staphylococcal protein A-formulated immune complexes suppress enterotoxin-induced cellular responses in nasal polyps

BACKGROUND

Recent studies have revealed that Staphylococcus aureus and its components participate in the pathogenesis of eosinophilic airway diseases, such as chronic rhinosinusitis with nasal polyps.

OBJECTIVE

We sought to determine whether staphylococcal protein A (SpA) from S aureus regulated cellular responses in nasal polyps, especially when coupled to immunoglobulins in immune complexes (ICs).

METHODS

Dispersed nasal polyp cells (DNPCs) or peripheral blood monocytes were cultured in vitro with SpA in the presence or absence of IgG, and IL-5, IL-13, IFN-γ, IL-17A, and IL-10 levels were measured in the supernatants. The effect of SpA exposure on staphylococcal enterotoxin B-induced cytokine production by DNPCs in the presence and absence of IgG, IgA, and autologous serum was also examined.

RESULTS

Exposure to SpA induced DNPCs to produce significantly higher IL-10, IL-13, and IL-17A levels than DNPCs without SpA, although the magnitude of the IL-17A increase was less than that of IL-10 and IL-13. SpA induced IL-10 production mainly from adherent DNPCs, and this was significantly enhanced in the presence of IgG; similar results were observed in peripheral blood monocytes. IC formation between SpA and IgG (SpA-IgG ICs) was confirmed by using native polyacrylamide gel electrophoresis. SpA-IgG ICs, but not SpA alone, almost completely suppressed staphylococcal enterotoxin B-induced IL-5, IL-13, IFN-γ, and IL-17A production by DNPCs; similar inhibition was observed in DNPCs treated with SpA in the presence of either IgA or autologous serum.

CONCLUSIONS

Our results suggest that SpA can regulate the pathogenesis of enterotoxin-induced inflammation in patients with chronic rhinosinusitis with nasal polyps through coupling to immunoglobulins.

Cellular responses to Staphylococcus aureus alpha-toxin in chronic rhinosinusitis with nasal polyps

BACKGROUND

In contrast to Staphylococcus aureus-derived superantigenic exotoxins, the role of non-superantigenic exotoxins in the pathogenesis of eosinophilic airway diseases remains obscure. We sought to characterize S. aureus alpha-toxin-induced cellular responses in chronic rhinosinusitis with nasal polyps (CRSwNP).

METHODS

Dispersed nasal polyp cells and uncinate tissue cells were prepared from patients with CRS with and without nasal polyps, respectively. Cells were incubated with various concentrations of alpha-toxin or staphylococcal enterotoxin B and then the levels of IL-5, IL-13, IFN-γ, IL-17A, and IL-10 in the cell supernatants were determined. The pathophysiological significance of alpha-toxin-induced cytokine production was also determined including radiological severity of rhinosinusitis, tissue and blood eosinophilia, serum total IgE level, and 1-s forced expiratory volume/forced vital capacity ratio (FEV1/FVC).

RESULTS

Nasal polyp cells produced substantial amounts of IL-5, IL-13, IFN-γ, IL-17A, and IL-10 in response to alpha-toxin. Cytokine production was higher in nasal polyp cells than in uncinate tissue cells. The potency of alpha-toxin in stimulating IL-5, IL-13, and IL-10 production was comparable to that of enterotoxin. Alpha-toxin-induced IFN-γ, IL-17A, and IL-10 production significantly and negatively correlated with the degree of eosinophil infiltration into nasal polyps. Conversely, alpha-toxin-induced IFN-γ and IL-10 production significantly and positively correlated with FEV1/FVC. IL-10 production was significantly lower in asthmatic patients compared to non-asthmatics

CONCLUSIONS

S. aureus-derived alpha-toxin can provoke cellular responses in nasal polyps. These responses, especially failure to synthesize IL-10, may play a role in the pathophysiology of CRSwNP.

Developments in the field of allergy in 2012 through the eyes of Clinical & Experimental Allergy

In 2012, we received 683 submissions and published 20 editorials, 38 reviews, 11 letters and 128 original articles. This represents an acceptance rate for original papers in the range of 20%. About 30% of original papers were triaged not to go out to review, either because the editors did not feel they had sufficient priority for publication or because the topic did not feel right for the readers of the journal. We place great emphasis on obtaining sufficient high-quality reviews to make our decisions on publication fair and consistent. Inevitably, however, there is a degree of luck about what gets published and which papers miss out, and we are always happy to receive an appeal on our decisions either at the triage stage or after review. This gives us the opportunity to revisit the decision and revise it or explain in more detail to the authors the basis for the decision. Once again in 2012, we were delighted by the quality of the papers submitted and the breadth and depth of research into allergic disease that it revealed. The pattern of papers submitted was similar in previous years with considerable emphasis on all aspects of asthma and rhinitis. We were particularly pleased with our special issue on severe asthma. Elucidating mechanisms using either animal models or patients has always been a major theme of the journal, and the excellent work in these areas has been summarized by Harissios Vliagoftis with a particularly interesting section on early-life events guiding the development of allergic disease, which understandably continue to be a major theme of research. Magnus Wickman summarized the papers looking at the epidemiology of allergic disease including work from birth cohorts, which are an increasingly rich source of data on risk factors for allergic disease, and two papers on the epidemiology of anaphylaxis. Giovanni Passalacqua discussed the papers in the clinical allergy section of the journal, and Adriano Mari who runs the excellent Allergome website discussed the papers looking at allergens including characterization and the relative usefulness of allergen arrays versus single extracts in diagnosis and management.