Clinical Significance of Cytoplasmic IgE-Positive Mast Cells in Eosinophilic Chronic Rhinosinusitis

Gαi1/3 signaling mediates IL-5-induced eosinophil activation and type 2 inflammation in eosinophilic chronic rhinosinusitis

Background

Uncontrolled severe eosinophilic chronic rhinosinusitis (eCRS) is associated with elevated levels of Th2 cells and raised immunoglobulin concentrations in nasal polyp tissue. eCRS is characterized by high eosinophilic infiltration and type 2 inflammation. Gαi1/3 proteins participate in allergic inflammation by regulating immune cells. Whether Gαi1/3 proteins have a role in the development of eCRS remains unknown.

Objectives

To investigate the association between Gαi1/3 expression levels and CRS and the underlying mechanisms.

Methods

Western blotting and immunohistology were used to detect Gαi1/3 expression. Correlations between Gαi1/3 and immune cells and clinical parameters were analyzed. Signaling pathway activation in IL-5-induced Gαi1/3-knockout or knockdown mouse embryonic fibroblasts (MEFs) and eosinophils (EoL-1 cells) was detected by western blotting. EdU/DAPI was used to evaluate the proliferation of EoL-1 cells. A CRS model was established using Gαi1/3-knockout mice, and histological analysis and inflammatory cytokine measurements were performed.

Results

Compared with the non-eCRS subset, the eCRS subset showed significantly increased Gαi1/3 expression levels. High nasal tissue Gαi1/3 levels were linked to high tissue eosinophil infiltration, and high disease severity and allergic conditions in CRS patients. Gαi1/3 were required for IL-5-induced Akt-mTOR and Erk activation in MEFs. In EoL-1 cells, Gαi1/3 was associated with IL-5-activated IL-5Rα, promoting IL-5Rα endocytosis and transducing downstream signaling. IL-5-induced EoL-1 cell proliferation and degranulation were suppressed after Gαi1/3 silencing. In a CRS murine model, immune cell infiltration and type 2 inflammation were largely impaired in Gαi1/3-double-knockout mice.

Conclusion

Increased Gαi1/3 expression levels in nasal tissue are linked to eosinophil infiltration and increased disease severity in CRS patients. Gαi1/3 contributes to eosinophil activation and participates in regulating allergic inflammation in CRS patients.

Personalized Medicine in Chronic Rhinosinusitis: Treatable Traits Using Biologics for Unmet Needs

Chronic rhinosinusitis (CRS) is a prevalent airway disease, leading to health, social, and economic burdens, and substantially impairs quality of life. As CRS is heterogeneous and contains diverse pathogenesis, treatment outcomes and prognosis vary from curative to intractable. Inflammatory endotypes of CRS are divided into 3 types-type 1, type 2 and type 3-based on cytokines promoted. Tissue/blood eosinophilia seems to be the most reliable and feasible biomarker for type 2 CRS in clinical settings, although the cutoff level of eosinophilia remains to be elucidated. In East Asia, the predominant pathogenesis has changed from neutrophilic type 3 inflammation to eosinophilic type 2 inflammation over the past decades. The treatment strategy for CRS has also evolved from classical phenotype-based "reliever-controller" treatment to endotype-based "treatable traits" treatment. "Treatable traits" treatment is a personalized approach for the management of airway disease with complex and heterogeneous conditions. In CRS, traits can be grouped into sinonasal, extra-nasal and risk factor/behavioral domains. Type 2 CRS is one of the sinonasal traits, and biologics targeting immunoglobulin E, interleukin (IL)-5 and its receptor, IL-4/IL-13 receptor (IL-4/IL-13R) and thymic stromal lymphopoietin are the corresponding treatments for this trait. Proper use of these biologics can achieve high efficacy with patient satisfaction, leading to clinical remission. However, some cases show marked hypereosinophilia after the reduction or discontinuation of systemic corticosteroid or the switching of biologics from anti-IL-5/IL-5R to anti-IL-4Rα monoclonal antibody. More precise research on CRS targeting endotype, genotype, regiotype and theratype is needed to address the unmet needs and refine the "treatable traits" treatment of CRS.

Update on the Biological and Clinical Relevance of Mast Cells in Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common inflammatory disorder whose complex immunopathogenesis has yet to be fully elucidated. Endotype-2 CRSwNP is the most common form of disease where eosinophils are the main drivers of inflammation. Traditional treatments for CRSwNP have centered around intranasal or systemic corticosteroids and endoscopic sinus surgery (ESS). However, recent advancements in targeted therapies have introduced novel biological agents that specifically target key inflammatory mediators such as IL-4, IL-5, and IL-13. These biologics offer promising options for patients with CRSwNP, particularly those who do not respond adequately to conventional treatments. Nonetheless, some patients do not satisfactorily respond to these drugs because of an insufficient blockade of the inflammatory process. The mast cell (MC) is another important (and somehow neglected) actor in the pathogenesis of CRSwNP, and the latest clinical and translational evidence in this field has been reviewed in the present paper.

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.

WLJP-025p, a homogeneous Lonicera japonica polysaccharide, attenuates atopic dermatitis by regulating the MAPK/NFκB/AP-1 axis via Act1

Atopic dermatitis (AD) is usually treated with steroids, but long-term use is not an effective cure because side effects and disease aggravation. Therefore, more effective and safer treatments are needed. Using dexamethasone as the positive control, the mechanism of action of water-extracted homogeneous honeysuckle Lonicera japonica polysaccharide (WLJP-025p) to alleviate AD was studied. Mice were administered 2,4-dinitrochlorobenzene in their bare back and right ear to mimic an AD model. The efficacy of WLJP-025p in AD was assessed by measuring right ear thickness and skin lesion scores, pathological observation (haematoxylin-eosin and toluidine blue staining), and serum IgE and IL-1β concentrations. The expression of relevant genes and proteins in the serum and back skin was detected using RT-qPCR, ELISA, western blotting, and immunofluorescence. Molecular docking and dynamic simulation of WLJP-025p and Act1 were performed. WLJP-025p considerably alleviated skin hyperplasia and pathological abnormalities in AD mice and inhibited the expression of Act1, Nucleus-P65, Nucleus-AP-1, and MAPK-related proteins in skin tissues. WLJP-025p formed a stable conformation with Act1, inhibited splenic Th17 differentiation, IL-17 release, and upregulated the expression of related skin barrier proteins. In conclusion, WLJP-025p affects the inflammation regulation via the MAPK/NFκB/AP-1 axis by binding to Act1, promotes the recovery of epithelial barrier function, and alleviates AD in mice.

Clinical feature-based diagnosis criteria of eosinophil and non-eosinophil chronic rhinosinusitis in Taiwan

Background

The prevalence of eosinophilic chronic rhinosinusitis (ECRS) has increased in Taiwan with a higher recurrence rate of nasal polyps after surgery. Therefore, we aimed to formulate the pre-operative diagnostic criteria for patients with ECRS in Taiwan.

Methods

This case-control study included patients diagnosed with CRS with nasal polyps (CRSwNP) who underwent functional endoscopic sinus surgery (FESS) at a tertiary hospital in Taiwan. The patients were classified into ECRS and non-eosinophilic CRS (NECRS) groups based on their histopathology. Demographic data, symptom severity scores, and computed tomography findings of the two groups were analyzed. We utilized receiver operating characteristic curve (ROC) analysis to evaluate parameters that could predict the diagnosis of ECRS.

Results

Total 408 CRSwNP patients were enrolled (ECRS group: 163; NECRS group: 245). ECRS group was strongly associated with asthma (6.1% vs. 2.0%, p = .03), higher blood eosinophil counts (4.3% vs. 2.7%, p < .01), higher serum IgE (285.3 vs. 50.2 IU/mL, p = .02), and higher 22-item Sino-Nasal Outcome Test (SNOT-22) score (40.5 vs. 36.7, p = .03). The ECRS criteria based on ROC curve included the SNOT-22 (>45, 2 points), serum eosinophil count percentage (>4%, 4 points), asthma (4 points), total serum IgE (>140 IU/mL, 4 points), Lund-Mackay score (>9.5, 4 points), and ethmoid-to-maxillary opacification ratio on CT (>1.5, 5 points). The cutoff score was 14 points (sensitivity, 70.2%; specificity, 93.3%).

Conclusions

Clinical-feature-based criteria may predict the diagnosis of ECRS before FESS in Taiwan.

Level of Evidence

Level 3.

Involvement of CD40-CD40L and ICOS-ICOSL in the development of chronic rhinosinusitis by targeting eosinophils

Background

Chronic rhinosinusitis (CRS), whose prevalence and pathogenesis are age-related, is characterized by nasal tissue eosinophil infiltration. CD40-CD40 ligand (CD40L) pathway involves in the eosinophil-mediated inflammation, and inducible co-stimulator (ICOS)-ICOS ligand (ICOSL) signal can strengthen CD40-CD40L interaction. Whether CD40-CD40L and ICOS-ICOSL have a role in the development of CRS remains unknown.

Objectives

The aim of this study is to investigate the association of CD40-CD40L and ICOS-ICOSL expression with CRS and underlying mechanisms.

Methods

Immunohistology detected the expression of CD40, CD40L, ICOS, and ICOSL. Immunofluorescence was performed to evaluate the co-localizations of CD40 or ICOSL with eosinophils. Correlations between CD40-CD40L and ICOS-ICOSL as well as clinical parameters were analyzed. Flow cytometry was used to explore the activation of eosinophils by CD69 expression and the CD40 and ICOSL expression on eosinophils.

Results

Compared with the non-eCRS subset, ECRS (eosinophilic CRS) subset showed significantly increased CD40, ICOS, and ICOSL expression. The CD40, CD40L, ICOS, and ICOSL expressions were all positively correlated with eosinophil infiltration in nasal tissues. CD40 and ICOSL were mainly expressed on eosinophils. ICOS expression was significantly correlated with the expression of CD40-CD40L, whereas ICOSL expression was correlated with CD40 expression. ICOS-ICOSL expression positively correlated with blood eosinophils count and disease severity. rhCD40L and rhICOS significantly enhanced the activation of eosinophils from patients with ECRS. Tumor necrosis factor-α (TNF-α) and interleukin-5 (IL-5) obviously upregulated CD40 expression on eosinophils, which was significantly inhibited by the p38 mitogen-activated protein kinase (MAPK) inhibitor.

Conclusions

Increased CD40-CD40L and ICOS-ICOSL expressions in nasal tissues are linked to eosinophils infiltration and disease severity of CRS. CD40-CD40L and ICOS-ICOSL signals enhance eosinophils activation of ECRS. TNF-α and IL-5 regulate eosinophils function by increasing CD40 expression partly via p38 MAPK activation in patients with CRS.

Spotlight on a Short-Time Treatment with the IL-4/IL-13 Receptor Blocker in Patients with CRSwNP: microRNAs Modulations and Preliminary Clinical Evidence

Already used for the treatment of some allergic and inflammatory diseases, such as asthma or atopic dermatitis, dupilumab has also been approved as add-on therapy for patients with CRSwNP, and it could represent the keystone to reducing the remission time as well as to improve healing and quality of life. On the other hand, the role of miRNAs as potential biomarkers of immune modulation is emerging. We analyzed the effects of a short-time treatment with dupilumab in patients with CRSwNP, analyzing the immune response modification as well as miRNAs modulations. First, in this early observation stage, all patients experienced remarkable improvement and were clinically stable. Indeed, we observed a significant decrease in CD4+ T cells and a significant reduction in total IgE (p < 0.05) and serum IL-8 levels (p < 0.01), indicating a reduction in the general inflammatory condition. In addition, we analyzed a panel of about 200 circulating miRNAs. After treatment, we noted a significant downregulation of hsa-mir-25-3p (p-value = 0.02415) and hsa-mir-185-5p (p-value = 0.04547), two miRNAs involved in the proliferation, inflammation, and dug-resistance, in accordance with the clinical status of patients. All these preliminary data aimed to identify new biomarkers of prognosis, identifiable with non-invasive procedures for patients. Further, these patients are still under observation, and others with different levels of responsiveness to treatment need to be enrolled to increase the statistical data.

The Percentage of PNAd-Expressing Vessels is Correlated with Disease Severity in Eosinophilic Chronic Rhinosinusitis

BACKGROUND

Eosinophilic chronic rhinosinusitis (ECRS) is a chronic inflammatory condition of the paranasal sinuses characterized by intractable nasal polyps with prominent eosinophil infiltration. These eosinophils are presumably recruited from peripheral blood via vessels expressing peripheral lymph node addressin (PNAd), a set of glycoproteins decorated with 6-sulfo sialyl Lewis x (sLe^x) glycans that serve as L-selectin ligands. Based on the severity classification algorithm proposed by the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) study group, ECRS is divided into mild, moderate and severe groups; however, as yet there are few reports comparing the clinicopathological differences among these groups.

OBJECTIVE

Our goal was to elucidate clinicopathological differences among the three different severities of ECRS with special reference to eosinophils and PNAd-expressing vessels.

METHODS

We performed quantitative immunohistochemical analysis of PNAd-expressing vessels using surgical specimens of nasal polyps from patients exhibiting varying severity of ECRS (n = 35) and from individuals with non-ECRS (n = 10). To this end, we immunostained tissue sections with anti-PNAd and anti-CD34 monoclonal antibodies, and then determined the number of vessels immunolabeled with each antibody.

RESULTS

The number of eosinophils infiltrating nasal polyps was correlated with ECRS severity. We also found that the PNAd + /CD34 + vessel ratio, namely, the percentage of PNAd-expressing vessels among all vessels, was positively correlated not only with ECRS severity but also with the number of eosinophils infiltrating nasal polyps formed in ECRS.

CONCLUSION

These results strongly suggest that PNAd-expressing vessels play at least a partial role in eosinophil recruitment to nasal polyps and consequent severity of ECRS.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.