Local Immunoglobulin E in nasal polyps: Role and modulation

Molecular mimicry-driven autoimmunity in chronic rhinosinusitis with nasal polyps

BACKGROUND

The pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) remains a subject of discussion. Although both microbial infection and autoimmunity have been proposed as potential contributors to CRSwNP pathobiology, their respective roles and intricate interactions in disease progression remain unclear owing to the limited knowledge regarding dysregulated humoral immunity in CRSwNP.

OBJECTIVE

To deepen understanding of CRSwNP, we sought to identify the precise humoral antigens targeted by dominant B-cell clones within the disease environments.

METHODS

Immunoglobulin repertoire sequencing was performed to identify dominant B-cell clones in CRSwNP tissues. These immunoglobulin clones were reconstructed as antibodies, which were then used in immunoprecipitation and antigen array experiments for hypothesis-free global antigen profiling of autogenous and exogenous antigens.

RESULTS

From analysis of 13 patients with CRSwNP, 31 antibodies were reconstructed from dominant B-cell clones identified in 9 patients. Seven novel protein autoantigens were identified, 5 of which were nucleic acid-binding proteins, and all were associated with autoimmune diseases. Additionally, 9 microbial antigens, including various viruses, bacteria, and fungi, were discovered. Notably, 2 antibodies demonstrated dual reactivity, simultaneously recognizing both microbial and human proteins. For example, 1 antibody targeted cytomegalovirus, Clostridium tetani, and human PLEC, whereas another recognized Aspergillus niger and human DLAT, through molecular mimicry of shared amino acid homologies.

CONCLUSION

Our data indicate the possibility that the pathobiology of CRSwNP involves autoreactive humoral immunity, with a subset of cases potentially exhibiting molecular mimicry-driven autoimmune features triggered by microbial infections. Nevertheless, this hypothesis requires further investigation.

Biological therapy in chronic rhinosinusitis with nasal polyps

INTRODUCTION

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogeneous disease. High proportions of patients with CRSwNP characterized by type 2 inflammation fail to gain adequate control with conventional treatment. The application of biologics in clinics and assessments of novel biologics in clinical trials are blooming in expectations to fulfill the unmet medical needs of patients with CRSwNP with type 2 inflammation.

AREAS COVERED

After an extensive search of PubMed, Medline, and EMBASE for the most recent evidence, we thoroughly summarize current advances in biological therapies for treating patients with CRSwNP.

EXPERT OPINION

In recent years, biological therapy has been in the spotlight in clinical studies on CRSwNP. Biologics have proven to be efficacious in reducing nasal polyp size, alleviating CRSwNP-related symptoms, improving quality of life, and reducing the need for systemic corticosteroids or endoscopic sinus surgery for nasal polyps. The considerable efficacy and safety profile of biologics has offered patients with refractory CRSwNP another treatment option. However, some concerns remain to be addressed. Aspects such as the position of biological therapy in the management of CRSwNP, traits of patients suitable for certain biologics, etc. necessitate efforts to elucidate these unknowns in order to provide patients with tailored therapy.

Relationship between serum ECP and TIgE levels and the risk of postoperative recurrence in patients with chronic rhinosinusitis with nasal polyps

Objective

This study was undertaken to assess the association between the likelihood of surgical recurrence and serum ECP and TIgE levels in chronic rhinosinusitis with nasal polyps (CRSwNP).

Methodology

Clinical information was gathered retrospectively from 166 cases of surgically treated CRSwNP as well as 60 cases of chronic rhinosinusitis without nasal polyps (CRSsNP). A comparative analysis on serum levels of total immunoglobulin E (TIgE) and eosinophil cationic protein (ECP) was carried out between the two groups. The CRSwNP patients were assigned into recurrence and non-recurrence groups based on the absence/presence of disease recurrence after a 2-year follow-up. An analysis was conducted on the correlation between the patients' clinical data and their serum ECP and TIgE levels. Receiver operating characteristic (ROC) curves were utilized to assess the clinical utility of these two biomarkers.

Results

The CRSwNP participants had higher serum levels of ECP and TIgE (4.28 ± 0.81 > 3.58 ± 0.77 ng/L, P < 0.001; 52.99 ± 8.62 > 15.65 ± 3.25 KU/L, P < 0.001) compared to CRSsNP participants. Univariate analysis indicated that neutrophil ratio, lymphocyte ratio, Lund-Kennedy score, Lund-Mackay score, SNOT-22 score, olfactory function score, and postoperative recurrence were significantly correlated with serum ECP and TIgE levels. Higher serum levels of TIgE and ECP (4.89 ± 0.79 < 4.11 ± 0.72, P < 0.001; 58.74 ± 8.27 < 51.40 ± 8.04, P < 0.001) were detected in the recurrence groups vs. the non-recurrence group. Multivariate analysis showed that serum ECP and TIgE were independent risk factors for recurrence of CRSwNP. Serum ECP and TIgE levels were found to be predictive of postoperative recurrence risk in CRSwNP patients (AUC: 0.77, 0.74, 0.84; P < 0.05) according to ROC curve analysis. Significant differences were not observed in any general clinical data.

Conclusion

The findings suggest that elevated serum ECP and TIgE levels in patients with CRSwNP can be as good predictors for the risk of recurrence after endoscopic sinus surgery.

[Immunoglobulin E in nasal secretions]

Diagnosis of allergic disease is primarily verified by IgE blood serum analysis. Determination in nasal secretions is technically more difficult, particularly due to a low specimen volume and the method of sample collection. Nasal secretions are frequently collected by lavage, which allows qualitative diagnostics, whereas swabs with defined amounts of mucus enable quantitative analyses. In the case of negative skin and serum tests, detection of IgE in nasal mucus combined with nasal provocation testing aids differentiation between local allergic and nonallergic rhinitis.

Whence and wherefore IgE?

Despite the near ubiquitous presence of Ig-based antibodies in vertebrates, IgE is unique to mammals. How and why it emerged remains mysterious. IgE expression is greatly constrained compared to other IgH isotypes. While other IgH isotypes are relatively abundant, soluble IgE has a truncated half-life, and IgE plasma cells are mostly short-lived. Despite its rarity, IgE is consequential and can trigger life-threatening anaphylaxis. IgE production reflects a dynamic steady state with IgG memory B cells feeding short-lived IgE production. Emerging evidence suggests that IgE may also potentially be produced in longer-lived plasma cells as well, perhaps as an aberrancy stemming from its evolutionary roots from an antibody isotype that likely functioned more like IgG. As a late derivative of an ancient systemic antibody system, the benefits of IgE in mammals likely stems from the antibody system's adaptive recognition and response capability. However, the tendency for massive, systemic, and long-lived production, common to IgH isotypes like IgG, were likely not a good fit for IgE. The evolutionary derivation of IgE from an antibody system that for millions of years was good at antigen de-sensitization to now functioning as a highly specialized antigen-sensitization function required heavy restrictions on antibody production-insufficiency of which may contribute to allergic disease.

Epithelium-derived kallistatin promotes CD4+ T-cell chemotaxis to TH2-type inflammation in chronic rhinosinusitis

BACKGROUND

The function of kallistatin in airway inflammation, particularly chronic rhinosinusitis with nasal polyps (CRSwNP), has not been elucidated.

OBJECTIVE

We sought to investigate the role of kallistatin in airway inflammation.

METHODS

Kallistatin and proinflammatory cytokine expression levels were detected in nasal polyps. For the in vivo studies, we constructed the kallistatin-overexpressing transgenic mice to elucidate the role of kallistatin in airway inflammation. Furthermore, the levels of plasma IgE and proinflammatory cytokines in the airways were evaluated in the kallistatin-/- rat in vivo model under a type 2 inflammatory background. Finally, the Notch signaling pathway was explored to understand the role of kallistatin in CRSwNP.

RESULTS

We showed that the expression of kallistatin was significantly higher in nasal polyps than in the normal nasal mucosa and correlated with IL-4 expression. We also discovered that the nasal mucosa of kallistatin-overexpressing transgenic mice expressed higher levels of IL-4 expression, associating to TH2-type inflammation. Interestingly, we observed lower IL-4 levels in the nasal mucosa and lower total plasma IgE of the kallistatin-/- group treated with house dust mite allergen compared with the wild-type house dust mite group. Finally, we observed a significant increase in the expression of Jagged2 in the nasal epithelium cells transduced with adenovirus-kallistatin. This heightened expression correlated with increased secretion of IL-4, attributed to the augmented population of CD4+CD45+Notch1+ T cells. These findings collectively may contribute to the induction of TH2-type inflammation.

CONCLUSIONS

Kallistatin was demonstrated to be involved in the CRSwNP pathogenesis by enhancing the TH2 inflammation, which was found to be associated with more expression of IL-4, potentially facilitated through Jagged2-Notch1 signaling in CD4+ T cells.

Intranasal delivery of low-dose anti-CD124 antibody enhances treatment of chronic rhinosinusitis with nasal polyps

Frequent injections of anti-CD124 monoclonal antibody (αCD124) over long periods of time are used to treat chronic rhinosinusitis with nasal polyps (CRSwNP). Needle-free, intranasal administration (i.n.) of αCD124 is expected to provide advantages of localized delivery, improved efficacy, and enhanced medication adherence. However, delivery barriers such as the mucus and epithelium in the nasal tissue impede penetration of αCD124. Herein, two novel protamine nanoconstructs: allyl glycidyl ether conjugated protamine (Nano-P) and polyamidoamine-linked protamine (Dendri-P) were synthesized and showed enhanced αCD124 penetration through multiple epithelial layers compared to protamine in mice. αCD124 was mixed with Nano-P or Dendri-P and then intranasally delivered for the treatment of severe CRSwNP in mice. Micro-CT and pathological changes in nasal turbinates showed that these two nano-formulations achieved ∼50 % and ∼40 % reductions in nasal polypoid lesions and eosinophil count, respectively. Both nano-formulations provided enhanced efficacy in suppressing nasal and systemic Immunoglobulin E (IgE) and nasal type 2 inflammatory biomarkers, such as interleukin 13 (IL-13) and IL-25. These effects were superior to those in the protamine formulation group and subcutaneous (s.c.) αCD124 given at a 12.5-fold higher dose. Intranasal delivery of protamine, Nano-P, or Dendri-P did not induce any measurable toxicities in mice.

Visual and bibliometric analysis of chronic rhinosinusitis and nasal polyps

Background

Chronic rhinosinusitis (CRS) is a heterogeneous disease characterized by persistent sinonasal inflammation and sinus microbiome dysbiosis. Nasal polyps (NPs) are one of the main manifestations that cause diverse clinical symptoms of CRS.

Objective

We sought to conduct a bibliometric and visual analysis of articles on CRS and NPs published between 2003 and 2022 to provide researchers with the current state of research and potential directions.

Methods

We searched relevant articles from 2003 to 2022 in the Web of Science database. VOSviewer and the Bibliometrix R package were used to perform the bibliometric analysis.

Results

A total of 3907 publications were retrieved. The United States made the highest contributions to global research, followed by China. Northwestern University had the most publications. The most published author was C. Bachert, followed by R. P. Schleimer and R. J. Schlosser. The authors with the most co-citations were C. Bachert, W. J. Fokkens, and P. Gevaert. Moreover, the journal with the most publications was the International Forum of Allergy & Rhinology, and the Journal of Allergy and Clinical Immunology was the most cited. "Covid-19," "biologics," and "type 2 inflammation" were the top current research hotspots.

Conclusions

The United States and Northwestern University were the leading country and institution in researching CRS and NPs. C. Bachert was the most influential expert. The International Forum of Allergy & Rhinology and the Journal of Allergy and Clinical Immunology were leading journals. "Covid-19," "biologics," and "type 2 inflammation" were the trending topics.

Aberrant follicular regulatory T cells associate with immunoglobulin hyperproduction in nasal polyps with ectopic lymphoid tissues

BACKGROUND

Ectopic lymphoid tissues (eLTs) and associated follicular helper T (TFH) cells contribute to local immunoglobulin hyperproduction in nasal polyps (NPs). Follicular regulatory T (TFR) cells in secondary lymphoid organs counteract TFH cells and suppress immunoglobulin production; however, the presence and function of TFR cells in eLTs in peripheral diseased tissues remain poorly understood.

OBJECTIVE

We sought to investigate the presence, phenotype, and function of TFR cells in NPs.

METHODS

The presence, abundance, and phenotype of TFR cells in NPs were examined using single-cell RNA sequencing, immunofluorescence staining, and flow cytometry. Sorted polyp and circulating T-cell subsets were cocultured with autologous circulating naïve B cells, and cytokine and immunoglobulin production were measured by ELISA.

RESULTS

TFR cells were primarily localized within eLTs in NPs. TFR cell frequency and TFR cell/TFH cell ratio were decreased in NPs with eLTs compared with NPs without eLTs and control inferior turbinate tissues. TFR cells displayed an overlapping phenotype with TFH cells and FOXP3+ regulatory T cells in NPs. Polyp TFR cells had reduced CTLA-4 expression and decreased capacity to inhibit TFH cell-induced immunoglobulin production compared with their counterpart in blood and tonsils. Blocking CTLA-4 abolished the suppressive effect of TFR cells. Lower vitamin D receptor expression was observed on polyp TFR cells compared with TFR cells in blood and tonsils. Vitamin D treatment upregulated CTLA-4 expression on polyp TFR cells and restored their suppressive function in vitro.

CONCLUSIONS

Polyp TFR cells in eLTs have decreased CLTA-4 and vitamin D receptor expression and impaired capacity to suppress TFH cell-induced immunoglobulin production, which can be reversed by vitamin D treatment in vitro.

IgE directly affects eosinophil migration in chronic rhinosinusitis with nasal polyps through CCR3 and predicts the efficacy of omalizumab

BACKGROUND

Whether IgE affects eosinophil migration in chronic rhinosinusitis with nasal polyps (CRSwNP) remains largely unclear. Moreover, our understanding of local IgE, eosinophils, and omalizumab efficacy in CRSwNP remains limited.

OBJECTIVE

We investigated whether IgE acts directly on eosinophils and determined its role in omalizumab therapy.

METHODS

Eosinophils and their surface receptors were detected by hematoxylin and eosin staining and flow cytometry. IgE and its receptors, eosinophil peroxidase (EPX), eosinophilic cationic protein, and CCR3 were detected by immunohistochemistry and immunofluorescence. Functional analyses were performed on blood eosinophils and polyp tissues. Logistic regression was performed to screen for risk factors. Receiver operating characteristic curve was generated to evaluate the accuracy.

RESULTS

Both FcεRI and CD23 were expressed on eosinophils. The expression of FcεRI and CD23 on eosinophil in nasal polyp tissue was higher than in peripheral blood (both P < .001). IgE and EPX colocalized in CRSwNP. IgE directly promoted eosinophil migration by upregulating CCR3 in CRSwNP but not in healthy controls. Omalizumab and lumiliximab were found to be effective in restraining this migration, indicating CD23 was involved in IgE-induced eosinophil migration. Both IgE+ and EPX+ cells were significantly reduced after omalizumab treatment in those who experienced response (IgE+ cells, P = .001; EPX+ cells, P = .016) but not in those with no response (IgE+ cells, P = .060; EPX+ cells, P = .151). Baseline IgE+ cell levels were higher in those with response compared to those without response (P = .024). The baseline local IgE+ cell count predicted omalizumab efficacy with an accuracy of 0.811.

CONCLUSIONS

IgE directly promotes eosinophil migration, and baseline local IgE+ cell counts are predictive of omalizumab efficacy in CRSwNP.

Real-Life Effects of Omalizumab on Chronic Rhinosinusitis with Nasal Polyposis

Chronic rhinosinusitis with nasal polyposis (CRSwNP) is an inflammatory disease of the nasal and sinus mucosa. This inflammatory process is supported by a multitude of cytokines, including IL-4, IL-5, and IL-13 produced by Th2 cells, as well as by IgE produced by B lymphocytes in response to a stimulus. Omalizumab is an anti-IgE monoclonal antibody with well-recognized roles in allergic asthma and chronic spontaneous urticaria. The aim of this study was to evaluate the clinical efficacy of omalizumab in a cohort of 13 patients suffering from chronic rhinosinusitis with CRSwNP. The inclusion criteria considered were as follows: 18 years of age, with a diagnosis of chronic rhinosinusitis with severe nasal polyposis expressed by an NPS greater than or equal to 5 and/or a SNOT-22 greater than or equal to 50. In addition, in the enrolled patients, the classic treatment with corticosteroids had to have been suspended due to recurrence after surgery or lack of response. Our results highlighted that omalizumab treatment for 16 weeks improved the parameters analyzed: SNOT-22, NPS, NRS, and NCS. The clinical efficacy of omalizumab was further strengthened by a significant improvement in respiratory function as well as reductions in the nasal polyps' size and in the associated symptoms.

Exploring causal relationships between inflammatory cytokines and allergic rhinitis, chronic rhinosinusitis, and nasal polyps: a Mendelian randomization study

Objectives

Previous research has suggested connections between specific inflammatory cytokines and nasal conditions, including Allergic Rhinitis (AR), Chronic Rhinosinusitis (CRS), and Nasal Polyps (NP). However, a lack of robust research establishing the causal underpinnings of them. This Mendelian Randomization (MR) study aims to evaluate the causal relationships between 41 inflammatory cytokines and the incidence of AR, CRS and NP.

Methods

This study employed a two-sample MR design, harnessing genetic variations derived from publicly accessible genome-wide association studies (GWAS) datasets. AR data was sourced from a GWAS with 25,486 cases and 87,097 controls (identifier: ukb-b-7178). CRS data originated from a GWAS encompassing 1,179 cases and 360,015 controls (identifier: ukb-d-J32). NP data was extracted from a GWAS involving 1,637 cases and 335,562 controls (identifier: ukb-a-541). The data for 41 inflammatory cytokines were obtained from an independent GWAS encompassing 8,293 participants. Inverse variance weighted (IVW), MR Egger regression and Weighted median were used to evaluate the causalities of exposures and outcomes. A range of sensitivity analyses were implemented to assess the robustness of the results.

Results

The results revealed significant associations between elevated circulating levels of MIP-1α (odds ratio, OR: 1.01798, 95% confidence interval, CI: 1.00217-1.03404, p = 0.02570) and TNF-α (OR: 1.01478, 95% CI: 1.00225-1.02746, p = 0.02067) with an augmented risk of AR in the IVW approach. Heightened levels of circulating IL-2 exhibited a positive correlation with an increased susceptibility to NP in the IVW approach (OR: 1.00129, 95% CI: 1.00017-1.00242, p = 0.02434), whereas elevated levels of circulating PDGF-BB demonstrated a decreased risk of NP (OR: 0.99920, 95% CI: 0.99841-0.99999, p = 0.047610). The MR analysis between levels of 41 inflammatory cytokines and the incidence of CRS yielded no positive outcomes.

Conclusion

This investigation proposes a potential causal association between elevated levels of MIP-1α and TNF-α with an elevated risk of AR, as well as an increased risk of NP linked to elevated IL-2 levels. Furthermore, there appears to be a potential association between increased levels of circulating PDGF-BB and a reduced risk of NP.

Comprehensive analysis of mitophagy-related genes in diagnosis and heterogeneous endothelial cells in chronic rhinosinusitis: based on bulk and single-cell RNA sequencing data

Background: Chronic rhinosinusitis (CRS) is a complex inflammatory disorder affecting the nasal and paranasal sinuses. Mitophagy, the process of selective mitochondrial degradation via autophagy, is crucial for maintaining cellular balance. However, the role of mitophagy in CRS is not well-studied. This research aims to examine the role of mitophagy-related genes (MRGs) in CRS, with a particular focus on the heterogeneity of endothelial cells (ECs). Methods: We employed both bulk and single-cell RNA sequencing data to investigate the role of MRGs in CRS. We compiled a combined database of 92 CRS samples and 35 healthy control samples from the Gene Expression Omnibus (GEO) database and we explored the differential expression of MRGs between them. A logistic regression model was built based on seven key genes identified through Random Forests and Support Vector Machines - Recursive Feature Elimination (SVM-RFE). Consensus cluster analysis was used to categorize CRS patients based on MRG expression patterns and weighted gene co-expression network analysis (WGCNA) was performed to find modules of highly correlated genes of the different clusters. Single-cell RNA sequencing data was utilized to analyze MRGs and EC heterogeneity in CRS. Results: Seven hub genes-SQSTM1, SRC, UBA52, MFN2, UBC, RPS27A, and ATG12-showed differential expression between two groups. A diagnostic model based on hub genes showed excellent prognostic accuracy. A strong positive correlation was found between the seven hub MRGs and resting dendritic cells, while a significant negative correlation was observed with mast cells and CD8+ T cells. CRS could be divided into two subclusters based on MRG expression patterns. WGCNA analysis identified modules of highly correlated genes of these two different subclusters. At the single-cell level, two types of venous ECs with different MRG scores were identified, suggesting their varying roles in CRS pathogenesis, especially in the non-eosinophilic CRS subtype. Conclusion: Our comprehensive study of CRS reveals the significant role of MRGs and underscores the heterogeneity of ECs. We highlighted the importance of Migration Inhibitory Factor (MIF) and TGFb pathways in mediating the effects of mitophagy, particularly the MIF. Overall, our findings enhance the understanding of mitophagy in CRS, providing a foundation for future research and potential therapeutic developments.

IgE receptor of mast cells signals mediator release and inflammation via adaptor protein 14-3-3ζ

BACKGROUND

Mast cells (MCs) are tissue-resident immune cells that mediate IgE-dependent allergic responses. Downstream of FcεRI, an intricate network of receptor-specific signaling pathways and adaptor proteins govern MC function. The 14-3-3 family of serine-threonine phosphorylation-dependent adapter proteins are known to organize intracellular signaling. However, the role of 14-3-3 in IgE-dependent activation remains poorly defined.

OBJECTIVE

We sought to determine whether 14-3-3 proteins are required for IgE-dependent MC activation and whether 14-3-3 is a viable target for the treatment of MC-mediated inflammatory diseases.

METHODS

Genetic manipulation of 14-3-3ζ expression in human and mouse MCs was performed and IgE-dependent mediator release assessed. Pharmacologic inhibitors of 14-3-3 and 14-3-3ζ knockout mice were used to assess 14-3-3ζ function in a MC-dependent in vivo passive cutaneous anaphylaxis (PCA) model of allergic inflammation. Expression and function of 14-3-3ζ were assessed in human nasal polyp tissue MCs.

RESULTS

IgE-dependent mediator release from human MCs was decreased by 14-3-3ζ knockdown and increased by 14-3-3ζ overexpression. Deletion of the 14-3-3ζ gene decreased IgE-dependent activation of mouse MCs in vitro and PCA responses in vivo. Furthermore, the 14-3-3 inhibitor, RB-11, which impairs dimerization of 14-3-3, inhibited cultured MC and polyp tissue MC activation and signaling downstream of the FcεRI receptor and dose-dependently attenuated PCA responses.

CONCLUSION

IgE/FcεRI-mediated MC activation is positively regulated by 14-3-3ζ. We identify a critical role for this p-Ser/Thr-binding protein in the regulation of MC FcεRI signaling and IgE-dependent immune responses and show that this pathway may be amenable to pharmacologic targeting.

Type 2 chronic inflammatory diseases: targets, therapies and unmet needs

Over the past two decades, significant progress in understanding of the pathogenesis of type 2 chronic inflammatory diseases has enabled the identification of compounds for more than 20 novel targets, which are approved or at various stages of development, finally facilitating a more targeted approach for the treatment of these disorders. Most of these newly identified pathogenic drivers of type 2 inflammation and their corresponding treatments are related to mast cells, eosinophils, T cells, B cells, epithelial cells and sensory nerves. Epithelial barrier defects and dysbiotic microbiomes represent exciting future drug targets for chronic type 2 inflammatory conditions. Here, we review common targets, current treatments and emerging therapies for the treatment of five major type 2 chronic inflammatory diseases - atopic dermatitis, chronic prurigo, chronic urticaria, asthma and chronic rhinosinusitis with nasal polyps - with a high need for targeted therapies. Unmet needs and future directions in the field are discussed.

Molecular Basis of Plant Profilins' Cross-Reactivity

Profilins are ubiquitous allergens with conserved structural elements. Exposure to profilins from different sources leads to IgE-cross-reactivity and the pollen-latex-food syndrome. Monoclonal antibodies (mAbs) that cross-react with plant profilins and block IgE-profilin interactions are relevant for diagnosis, epitope mapping, and specific immunotherapy. We generated IgGs mAbs, 1B4, and 2D10, against latex profilin (anti-rHev b 8) that inhibit the interaction of IgE and IgG4 antibodies from sera of latex- and maize-allergic patients by 90% and 40%, respectively. In this study, we evaluated 1B4 and 2D10 recognition towards different plant profilins, and mAbs recognition of rZea m 12 mutants by ELISAs. Interestingly, 2D10 highly recognized rArt v 4.0101 and rAmb a 8.0101, and to a lesser extent rBet v 2.0101, and rFra e 2.2, while 1B4 showed recognition for rPhl p 12.0101 and rAmb a 8.0101. We demonstrated that residue D130 at the α-helix 3 in profilins, which is part of the Hev b 8 IgE epitope, is essential for the 2D10 recognition. The structural analysis suggests that the profilins containing E130 (rPhl p 12.0101, rFra e 2.2, and rZea m 12.0105) show less binding with 2D10. The distribution of negative charges on the profilins' surfaces at the α-helices 1 and 3 is relevant for the 2D10 recognition, and that may be relevant to explain profilins' IgE cross-reactivity.

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

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