Subepithelial inflammatory load and basement membrane thickening in refractory chronic rhinosinusitis with nasal polyposis: a histopathological study

ALOX15+ M2 macrophages contribute to epithelial remodeling in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Epithelial remodeling is a prominent feature of eosinophilic chronic rhinosinusitis with nasal polyps (eCRSwNP), and infiltration of M2 macrophages plays a pivotal role in the pathogenesis of eCRSwNP, but the underlying mechanisms remain undefined.

OBJECTIVE

We sought to investigate the role of ALOX15+ M2 macrophages in the epithelial remodeling of eCRSwNP.

METHODS

Digital spatial transcriptomics and single-cell sequencing analyses were used to characterize the epithelial remodeling and cellular infiltrate in eCRSwNP. Hematoxylin and eosin staining, immunohistochemical staining, and immunofluorescence staining were used to explore the relationship between ALOX15+ M2 (CD68+CD163+) macrophages and epithelial remodeling. A coculture system of primary human nasal epithelial cells (hNECs) and the macrophage cell line THP-1 was used to determine the underlying mechanisms.

RESULTS

Spatial transcriptomics analysis showed the upregulation of epithelial remodeling-related genes, such as Vimentin and matrix metalloproteinase 10, and enrichment of epithelial-mesenchymal transition (EMT)-related pathways, in the epithelial areas in eCRSwNP, with more abundance of epithelial basal, goblet, and glandular cells. Single-cell analysis identified that ALOX15+, rather than ALOX15-, M2 macrophages were specifically highly expressed in eCRSwNP. CRSwNP with high ALOX15+ M2THP-1-IL-4+IL-13 macrophages had more obvious epithelial remodeling features and increased genes associated with epithelial remodeling and integrity of epithelial morphology versus that with low ALOX15+ M2THP-1-IL-4+IL-13 macrophages. IL-4/IL-13-polarized M2THP-1-IL-4+IL-13 macrophages upregulated expressions of EMT-related genes in hNECs, including Vimentin, TWIST1, Snail, and ZEB1. ALOX15 inhibition in M2THP-1-IL-4+IL-13 macrophages resulted in reduction of the EMT-related transcripts in hNECs. Blocking chemokine (C-C motif) ligand 13 signaling inhibited M2THP-1-IL-4+IL-13 macrophage-induced EMT alteration in hNECs.

CONCLUSIONS

ALOX15+ M2 macrophages are specifically increased in eCRSwNP and may contribute to the pathogenesis of epithelial remodeling via production of chemokine (C-C motif) ligand 13.

Histopathologic features of biologic therapy nonresponders in chronic rhinosinusitis with nasal polyposis

BACKGROUND

Biologics are effective for chronic rhinosinusitis with nasal polyposis (CRSwNP) by reducing type 2 inflammation. Nonresponders often require functional endoscopic sinus surgery (FESS) and represent a challenging population potentially due to non-type 2 pathophysiology. This study characterizes the histopathologic features of biologic nonresponders.

METHODS

A retrospective review of 257 CRSwNP patients undergoing FESS was conducted. The biologic nonresponder group included patients with prior biologic therapy who exhibited persistent symptoms and polyp burden. Those with CRSwNP not prescribed biologic therapy were selected as controls. Demographics, comorbidities, and structured histopathology consisting of 13 variables were collected.

RESULTS

Of 257 CRSwNP patients, 20 were on biologics prior to FESS. Fourteen patients (70.0%) received dupilumab, one (5.0%) received mepolizumab, one (5.0%) received omalizumab, and four (20.0%) tried multiple biologics. The mean age for the biologic nonresponder group was 45.8 years compared to 50.4 years for the controls. Nonresponders had a significantly increased incidence of reduced tissue eosinophilia, defined as <5 per high power field (55% vs. 31.2%, p = 0.044) and increased basement membrane thickening (100% vs. 78.1%, p = 0.019). The remaining 11 variables did not reach statistical significance.

CONCLUSION

Histopathologic analysis of biologic nonresponders demonstrates decreased eosinophilia and thickened basement membranes. These findings, particularly low tissue eosinophils, are consistent with a non-type 2 CRSwNP that may be recalcitrant to biologic therapies. Histopathologic analysis done in conjunction with FESS may aid clinicians in understanding response to biologic therapies in patients with CRSwNP who have persistent symptom burden necessitating FESS.

Endotyping Difficult-to-Treat Chronic Rhinosinusitis with Nasal Polyps by Structured Histopathology

INTRODUCTION

This study aimed to identify the histopathologic characteristics associated with difficult-to-treat chronic rhinosinusitis with nasal polyps (CRSwNPs), enabling physicians to predict the risk of poor outcome after endoscopic sinus surgery (ESS).

METHODS

A prospective cohort study performed at the First Affiliated Hospital of Sun Yat-sen University between January 2015 and December 2018 with CRSwNP patients who underwent ESS. Polyp specimens were collected during surgery and were subjected to structured histopathological evaluation. Difficult-to-treat CRSwNPs were determined at 12-15 months post-operation according to the European Position Paper. Multiple logistic regression model was used to assess the association between histopathological parameters and the difficult-to-treat CRSwNP.

RESULTS

Among 174 subjects included in the analysis, 49 (28.2%) were classified with difficult-to-treat CRSwNP, which had higher numbers of total inflammatory cells, tissue eosinophils, and percentages of eosinophil aggregates and Charcot-Leyden crystals (CLC) formation but a lower number of interstitial glands than the nondifficult-to-treat CRSwNP. Inflammatory cell infiltration (adjusted OR: 1.017), tissue eosinophilia (adjusted OR: 1.005), eosinophil aggregation (adjusted OR: 3.536), and CLC formation (adjusted OR: 6.972) were independently associated with the difficult-to-treat outcome. Furthermore, patients with tissue eosinophil aggregation and CLC formation had an increasingly higher likelihood of uncontrolled disease versus those with tissue eosinophilia.

CONCLUSION

The difficult-to-treat CRSwNP appears to be characterized by increased total inflammatory infiltrates, tissue eosinophilia, eosinophil aggregation, and CLC formation in structured histopathology.

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.

Current evaluation and management of patients with chronic rhinosinusitis and nasal polyps

INTRODUCTION

A clear understanding of the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP) and its close association with other airway pathologies, especially asthma, helps to comprehend the concept of the united airway and the importance of a multidisciplinary approach and the actual roll of biologic therapy.

AREAS COVERED

This expert review is the synthesis of a working group on the current state of the art of the evaluation and management of CRSwNP. A thorough analysis of the literature has been conducted for the latest studies and results, specially the European (EPOS 2020) and American (ICAR-RS 2021) guidelines.

EXPERT OPINION

The roles of optimal medical treatment and indications for surgery are becoming clearer, but much research is still needed regarding the extent and radicality when surgery is indicated. The main objectives of this review were to provide a clear and updated description of treatments, their indication, follow-up, and response criteria. These steps are considering the broad spectrum of inflammation endophenotypes and the biologic therapy available. Understanding the role and limitations of each specialty is key for providing greatest benefit to the patient.

Deep Learning-Based Prediction of Treatment Prognosis from Nasal Polyp Histology Slides

BACKGROUND

Histopathology of nasal polyps contains rich prognostic information, which is difficult to objectively extract. In the present study, we aimed to develop a prognostic indicator of patient outcomes by analyzing scanned conventional haematoxylin and eosin (H&E) -stained slides alone using deep learning.

METHODS

An interpretable supervised deep learning model was developed using 185 H&E-stained whole-slide images (WSIs) of nasal polyps, each from a patient randomly selected from the pool of 232 patients who underwent endoscopic sinus surgery at the First Affiliated Hospital of Sun Yat-sen University (internal cohort). We internally validated the model on a holdout dataset from the internal cohort (47 H&E-stained WSIs) and externally validated the model on 122 H&E-stained WSIs from the Seventh Affiliated Hospital of Sun Yat-sen University and the University of Hong Kong-Shenzhen Hospital (external cohort). A poor prognosis score (PPS) was established to evaluate patient outcomes, and then risk activation mapping was applied to visualize the histopathological features underlying PPS.

RESULTS

The model yielded a patient-level sensitivity of 79.5%, and specificity of 92.3%, with areas under the receiver operating characteristic curve of 0.943, on the multi-center external cohort. The predictive ability of PPS was superior to that of conventional tissue eosinophil number. Notably, eosinophil infiltration, goblet cell hyperplasia, glandular hyperplasia, squamous metaplasia, and fibrin deposition were identified as the main underlying features of PPS.

CONCLUSIONS

Our deep learning model is an effective method for decoding pathological images of nasal polyps, providing a valuable solution for disease prognosis prediction and precise patient treatment. This article is protected by copyright. All rights reserved.

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.

Defining the Allergic Endotype of Chronic Rhinosinusitis by Structured Histopathology and Clinical Variables

BACKGROUND

Atopy has a strong association with chronic rhinosinusitis (CRS).

OBJECTIVE

To understand whether patients with atopy and CRS can be defined by markers of tissue histopathology, systemic biomarkers, and clinical factors, which may guide their response to new pharmacologic agents.

METHODS

In a retrospective cohort of CRS patients who underwent functional endoscopic sinus surgery, a structured histopathology report consisting of 12 variables, comorbid conditions, preoperative total serum IgE levels, and preoperative modified Lund-Kennedy endoscopic and sinonasal outcome test (SNOT-22) scores were compared between atopic CRS (aCRS) and non-aCRS control patients in a multivariable model.

RESULTS

A total of 380 CRS patients were enrolled, 286 of whom had comorbid atopy (aCRS). Compared with non-aCRS, aCRS patients had significantly higher preoperative total SNOT-22 scores (40.45 ± 22.68 vs 29.70 ± 20.68, P = .015) and symptom-specific SNOT-22 scores in all domains except psychological dysfunction. Relative to non-aCRS, aCRS patients had increased tissue eosinophilia (P < .0001), eosinophil aggregates (P < .0001), Charcot-Leyden crystals (P < .04), fibrosis (P < .02), total serum IgE levels (P < .04), polyploid disease (P < .001), and a prevalence of comorbid asthma (P < .0001) and aspirin exacerbated respiratory disease (AERD) (P < .003). Patients with aCRS demonstrated increased tissue eosinophilia compared with non-aCRS patients even after controlling for polypoid disease, asthma, and AERD.

CONCLUSION

In the context of CRS, atopy appears to be a specific predictor of CRS severity linked to specific histopathologic variables, including enhanced eosinophilic aggregates. Moving forward, allergic status may be a useful way to identify an atopic endotype of CRS patients. Furthermore, after surgery, patients are often maintained on intranasal corticosteroids. In patients whose disease is unresponsive to steroids, we may look to atopic status to identify another management therapy. Atopic CRS patients, irrespective of polyp and asthmatic status, could be optimal candidates for biologic agents such as T-helper cell, eosinophil, and/or IgE-targeted therapies.

Alteration of Histopathology in Recurrent Nasal Polyps

OBJECTIVE

The objective of this study was to analyze the histopathologic changes in recurrent nasal polyps (NPs) in terms of tissue inflammatory cells infiltration and mucosal remodeling.

METHODS

Thirty-five patients with primary NPs requiring a revision surgery during follow-up and a matched control group of 35 primary NP patients without recurrence were retrospectively enrolled. Histopathologic examination was performed of tissue inflammatory cells, subepithelial edema, epithelial cell hyperplasia, basement membrane thickness, and fibrosis.

RESULTS

The mean eosinophil and neutrophil counts, proportions of eosinophil and neutrophil, as well as total inflammatory cell count were significantly higher in the recurrent group than those in the controls. Higher subepithelial edema was seen in the recurrent group. Within the recurrent group, the mean tissue eosinophil count and relative eosinophilia reduced from the first operation to revision surgery, whereas neutrophil count and proportion, and total inflammatory cell counts remained unchanged. Subepithelial edema and epithelial cell hyperplasia were significantly reduced after the first surgical procedure.

CONCLUSION

NP recurrence is associated with higher inflammatory grade (especially in eosinophilia and neutrophilia). Surgical and corticoid treatments may have an impact on mucosal histopathologic changes but need further certification.

Distinct Patterns of Tissue Remodeling and Their Prognostic Role in Chronic Rhinosinusitis

INTRODUCTION

Tissue remodeling refers to structural changes that occur in damaged tissue and is associated with disease severity in asthma. However, the characteristics of tissue remodeling and its prognostic role in chronic rhinosinusitis (CRS) remain unclear. In this report, we evaluated the clinical implications of tissue remodeling in CRS.

METHODS

We performed a retrospective cohort study of adult patients who underwent endoscopic sinus surgery for bilateral CRS. The histopathology of sinus mucosa was determined by evaluating the inflammatory cell count and tissue remodeling markers (squamous metaplasia, subepithelial gland proliferation, basement membrane [BM] thickening, stromal edema, and fibrosis). Eosinophilic CRS (ECRS) was defined as an eosinophil count >15/high-power field in the biopsied tissue. Patient characteristics, allergy test grade, preoperative Lund-Mackay score (LMS), and pre- and postoperative Lund-Kennedy scores (LKSs) were analyzed.

RESULTS

Of the identified patients, 59.1% were classified as ECRS and the remaining 40.9% as non-ECRS. Regarding tissue remodeling markers, stromal edema was seen in 90.9%, BM thickening in 63.6%, and stromal fibrosis in 34.1% of patients. In cases with stromal edema and BM thickening, greater tissue eosinophilia was observed, while stromal fibrosis decreased tissue eosinophilia (p < 0.05). Prognostically, subepithelial gland proliferation alone was an independent risk factor for poor postoperative endoscopic findings (odds ratio: 8.250, 95% confidence interval: 1.128-60.319, p = 0.038).

CONCLUSIONS

Tissue eosinophilia was commonly associated with BM thickening and stromal edema. Subepithelial gland proliferation predicted a poor surgical prognosis in CRS. These findings imply that tissue remodeling provides additional information not only on the CRS endotype but also on the postsurgical prognosis.

Changes in Clinical and Histological Characteristics of Nasal Polyps in Northern China over the Past 2-3 Decades

INTRODUCTION

Recent studies have shown that inflammatory patterns of nasal polyps from patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) in East Asia have changed over time. However, to date there is a marked lack of similar data for CRSwNP in Northern China. This study thus aimed to assess the changes in the clinical and histological characteristics of CRSwNP patients from Northern China over the past 2-3 decades.

METHODS

This was a retrospective study, which examined data from 2 groups of 150 CRSwNP patients each, who had undergone endoscopic sinus surgery in Beijing Tongren Hospital from 1993 to 1995 (group A) and from 2015 to 2019 (group B). All relevant data for demographic, clinical, and histological parameters were collected for each patient from the 2 groups and compared for overall changes between the 2 groups.

RESULTS

The comorbidity of CRSwNP and asthma increased over time and the cellular phenotype of CRSwNPchanged significantly; in particular, the proportion of eosinophil-dominant CRSwNP increased, lymphocyte-dominant and plasma-dominant CRSwNP decreased significantly, and the proportions of neutrophil-dominant and mixed CRSwNP were not altered. The rate of polyp recurrence increased in CRSwNP but did not in eosinophilic CRSwNP. Smoking and age did not significantly impact the inflammatory patterns of CRSwNP.

CONCLUSIONS

The inflammatory patterns of CRSwNP patients have changed and comorbidity of asthma significantly increased in CRSwNP patients in Northern China over the past 2-3 decades.

Metallothionein-3 is a clinical biomarker for tissue zinc levels in nasal mucosa

OBJECTIVE

Recently, depleted tissue zinc levels were found in nasal mucosa from patients with chronic rhinosinusitis (CRS) in correlation with tissue eosinophilia, however, no clinical biomarkers for tissue zinc levels have been identified. Metallothionein-3 (MT3) is an intracellular zinc chelator and previous data showed MT3 mRNA levels to be reduced in CRS patients with nasal polyps (CRSwNP). In this study, we examined the correlation between MT3 expression and zinc levels in nasal mucosa and primary human nasal epithelial cells (HNECs) to investigate whether MT3 could be a clinical biomarker for tissue zinc levels.

METHOD

Tissue was harvested from 36 patients and mounted on tissue micro-array (TMA) slides. MT3 expression and tissue zinc fluorescence intensity were measured at different areas within the mucosa (surface epithelium and lamina propria) and compared between controls, CRSwNP and CRS without nasal polyps (CRSsNP) patients. MT3 mRNA and protein expression were examined in zinc-depleted HNECs by qPCR and immunofluorescence microscopy.

RESULTS

MT3 expression in CRSwNP was significantly decreased in both surface epithelium (p<0.001 to controls) and lamina propria (p = 0.0491 to controls). There was a significant positive correlation between tissue zinc levels and MT3 expression in nasal mucosa (r = 0.45, p = 0.007). In zinc-deplete HNECs, MT3 expression was significantly decreased at mRNA (p = 0.02) and protein level (p<0.01). There was a significant positive correlation between tissue zinc levels and MT3 expression within individual HNECs (r = 0.59, p<0.001).

CONCLUSIONS

MT3 expression reflects intramucosal zinc levels in both nasal mucosa and HNECs indicating MT3 could be used as a clinical biomarker for monitoring intracellular zinc levels in the nasal mucosa.

Predictive significance of arachidonate 15-lipoxygenase for eosinophilic chronic rhinosinusitis with nasal polyps

Background

Eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) exhibits a poorer outcome compared with non-eosinophilic chronic rhinosinusitis with nasal polyps (nonECRSwNP), so it is significant to identify effective markers to differentiate ECRSwNP in guiding the treatment strategies of these patients. Although arachidonate 15-lipoxygenase (ALOX15) is positioned as a marker of eosinophilic inflammation, its study in differentiating ECRSwNP has not been reported. The aim of this study is to assess the potential of ALOX15 in distinguishing and predicting ECRSwNP.

Methods

Forty-eight patients with chronic rhinosinusitis with nasal polyps (CRSwNP), including 30 ECRSwNP and 18 nonECRSwNP patients, were enrolled. ALOX15 mRNA level was determined in polyps by real-time polymerase chain reaction (RT-PCR). The patients’ baseline characteristics were evaluated and analyzed for correlations with ALOX15. Receiver operating characteristic (ROC) curve was used to assess the predictive significance of the potential predictors for ECRSwNP.

Results

ALOX15 mRNA level was significantly higher in ECRSwNP patients than in nonECRSwNP patients (P < 0.001). ALOX15 mRNA was significantly correlated with tissue and blood eosinophil percentages (r = 0.565, P < 0.001 and r = 0.395, P = 0.006), olfaction scores (r = 0.400, P = 0.005), total visual analogue scale (VAS) symptom scores (r = 0.383, P = 0.007), ethmoid/maxillary sinus (E/M) ratio (r = 0.463, P = 0.001), and endoscopy scores (r = 0.409, P = 0.004). Logistic regression analysis showed ALOX15 mRNA level and percentage of blood eosinophils to be predictive factors for ECRSwNP (P = 0.004 and P = 0.036, respectively). ROC curve indicated ALOX15 to have high predictive accuracy for ECRSwNP (area under the curve (AUC) = 0.909), which was further improved by combination of ALOX15 with percentage of blood eosinophils (AUC = 0.933).

Conclusions

The relative ALOX15 mRNA level alone or in combination with blood eosinophils might be a reliable biomarker for predicting a diagnosis of ECRSwNP.

Guidance for contemporary use of biologics in management of chronic rhinosinusitis with nasal polyps: discussion from a National Institutes of Health-sponsored workshop

BACKGROUND

Biologic medications are emerging as options for treating chronic rhinosinusitis with nasal polyps (CRSwNP). Several questions remain regarding patient selection, indications, clinical efficacy, and cost effectiveness.

METHODS

In November 2019, a group of physicians and scientists gathered to consider strategies for future studies regarding biologics. During the discussion, gaps in knowledge highlighted a need for a consensus on the present day use of biologics in polyp patients.

RESULTS

The goal of this guideline is to propose recommendations for the current use of biologics in CRSwNP as new evidence continues to emerge and inform practice.

CONCLUSION

We suggest that physicians evaluate patients on an individual basis and closely monitor for improvement due to the high cost and unknown long-term effects of biologics.

Histopathological characteristics of surgical tissue from primary vs recurrent chronic rhinosinusitis with nasal polyposis patients

OBJECTIVE

The histopathological characteristics of primary vs recurrent nasal polyps in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) have not been studied comprehensively. Identification of these features may be helpful for prognostication, postoperative management, and consideration of novel eosinophil-targeting biologic therapy. This study investigates the histopathological differences in primary vs recurrent CRSwNP tissue.

METHODS

Patients undergoing endoscopic sinus surgery for CRSwNP were included if all 13 histopathological and mucin characteristics on a standardized report were available. Histopathology parameters were compared in surgical tissue and mucin from primary vs recurrent CRSwNP.

RESULTS

Complete structured histopathology reports were available for 96 patients (39 primary polyps and 57 recurrent polyps). Compared to primary polyp tissue, recurrent CRSwNP mucin was significantly more likely to feature eosinophil aggregates (57.9% vs 35.9%; P = .047). Tissue eosinophilia (using a threshold >10 per high power field [HPF]) was not significantly different in primary and recurrent CRSwNP tissue. Other histopathologic parameters and clinical characteristics were similar.

CONCLUSION

Eosinophil aggregates on histopathology are significantly more likely to be present in recurrent CRSwNP. In the limited series, tissue eosinophilia (>10 per HPF) was not significantly different in primary and recurrent CRSwNP. Therefore, in addition to the study of tissue eosinophilia levels, Rhinologic surgeons should also direct attention to CRSwNP mucin. Mucin eosinophilic aggregates are an independent marker of severe inflammation that is associated more likely with recurrent vs primary polyposis. Further study of this marker may help determine its role of choice of postoperative medical therapies, including anti-eosinophilic biologics.

LEVEL OF EVIDENCE

4.

Current and Future Treatments of Rhinitis and Sinusitis

Advances in understanding the pathogenic mechanisms of both rhinitis and chronic rhinosinusitis have resulted in new treatment options, especially for chronic rhinosinusitis. A review of relevant medical and surgical clinical studies shows that intranasal corticosteroids, antihistamines, and allergen immunotherapy continue to be the best treatments for chronic rhinitis. Dupilumab is the first biologic approved for chronic rhinosinusitis with polyps. Omalizumab, mepolizumab, and benralizumab may have a future role in the treatment of chronic rhinosinusitis. Novel corticosteroid delivery devices such as an exhalation delivery system for fluticasone and bioabsorbable sinus implants provide enhanced and localized distribution of corticosteroids. Surgical management tailored to the underlying disease process improves clinical outcomes in chronic rhinosinusitis with or without nasal polyposis. Advances in the understanding of the heterogeneous nature of rhinitis and rhinosinusitis have resulted in more precise treatments. Improving the understanding of different endotypes should provide better knowledge to determine appropriate current and new therapies to treat these diseases.

Prognostic Significance of Serum Complement Component 3 in Chronic Rhinosinusitis with Nasal Polyps

OBJECTIVE

The aim of this study was to assess the relationship between serum complement component 3 (C3) levels and disease recurrences in patients with chronic rhinosinusitis with nasal polyps (NPs).

METHODS

Ninety-seven patients with NPs and 30 controls were recruited. Clinical features were collected. Serum concentrations of C3 and C4 were measured before and after endoscopic sinus surgery.

RESULTS

Compared to the controls, increased C3 levels were found in patients with NPs. Patients with polyp recurrences had higher pre- and postoperative serum C3 levels than patients without polyp recurrences. Serum C3 levels dropped after surgery. After polyp regrowth, the mean C3 level in the recurrent group elevated again to the degree similar to that before surgery. When patients were stratified by tissue eosinophilia, no significant difference was seen in pre-/postoperative, absolute change after surgery, and post-recurrent C3 levels between patients without and with eosinophilic NPs in the group with disease recurrences.

CONCLUSION

Serum C3 may be involved in the pathogenesis of NPs. Higher serum C3 levels may pinpoint patients at high risk of recurrence as an independent factor. Furthermore, the change in C3 levels after surgery may have the potential to serve as a predictor for polyp progression. Adding serum C3 measurement to the routine walk-up in the clinical management of NPs is worth further investigation and may help physicians make a more rational diagnostic and/or therapeutic decision regarding this disease.

The Association of Serum Eosinophilia with Structured Histopathology in Chronic Rhinosinusitis

Background:

Prior studies have demonstrated associations between serum eosinophilia and chronic rhinosinusitis (CRS) pathogenesis. However, the association of serum eosinophilia with histopathology profiling in CRS has not been fully delineated and may help better characterize CRS disease burden prior to surgery.

Methods:

A structured histopathology report of 13 variables was utilized to analyze sinus tissue removed during functional endoscopic sinus surgery (FESS). Complete blood count (CBC) with differential was drawn within 4 weeks prior to FESS. Serum eosinophilia was defined as >6.0% (>0.60 th/μL). Histopathology variables were compared among patients.

Results:

A total of 177 CRS patients (37 with serum eosinophilia and 140 with normal serum eosinophilia) were analyzed. Compared to CRS patients with normal serum eosinophil counts, CRS patients with serum eosinophilia demonstrated increased polypoid disease (67.6% vs 35.0%, P < .001), eosinophil aggregates (45.9% vs 20.7%, P = .003), and eosinophils per high-power field (>5/HPF) (67.6% vs 40.7%, P = .003).

Conclusion:

CRS patients with serum eosinophilia demonstrated severe disease burden on histopathology with high levels of polypoid disease and tissue eosinophilia. However, a considerable number of patients without serum eosinophilia demonstrated eosinophilic disease on histopathology, indicating that preoperative serum eosinophilia alone could not be reliably used to predict eosinophilic CRS.

Level of evidence:

4

A structured histopathology-based analysis of surgical outcomes in chronic rhinosinusitis with and without nasal polyps

Objectives

Structured histopathology reporting has been recently described for detailing immunopathological characteristics of chronic rhinosinusitis (CRS), and can be utilized for subtyping CRS and personalizing management. This study scrutinized elements of structured histopathology to identify characteristics that prognosticate outcomes following endoscopic sinus surgery (ESS) for CRS patients with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP).

Methods

Outcomes following ESS were measured using the patient‐reported 22‐item sinonasal outcome test (SNOT‐22). Changes in total SNOT‐22 scores at 6 and 12 months postoperatively were analyzed. Thirteen parameters reported in structured histopathology of sinus surgical tissue were studied for association with outcomes postsurgery. The overall cohort of all CRS patients was studied, along with subgroup analyses of CRSwNP and CRSsNP patients.

Results

In the entire CRS cohort (n = 171), eosinophil count >10 per high power field (HPF) was associated with greater improvement in SNOT‐22 scores at 6 months post‐ESS (P = .039). At 12 months follow‐up, no histopathological characteristic was associated with change in total SNOT‐22 score. In the CRSwNP (n = 66) subgroup, the presence of fibrosis (P = .006) and eosinophil count ≤10 per HPF (P = .025) were associated with less favorable changes in SNOT‐22 scores at 12 months follow‐up. Fibrosis remained statistically significant in multivariable analysis (P = .007).

Conclusions

At 6 months post‐ESS, tissue eosinophilia is associated with significantly higher improvement in SNOT‐22 scores, but this difference is diluted by 12 months. Fibrosis was associated with less favorable outcomes in SNOT‐22 scores for CRSwNP patients at 12 months and may be a prognosticator for poorer long‐term outcomes.

Level of Evidence

4

Histopathologic analysis in chronic rhinosinusitis: Impact on quality of life outcomes

OBJECTIVE

This study investigates the impact of histopathologic parameters on quality of life outcomes in patients with chronic rhinosinusitis.

SETTING

Hospital of Zhejiang University.

STUDY DESIGN

Retrospective analysis of collected data.

SUBJECTS AND METHODS

One hundred and twenty patients with chronic rhinosinusitis (CRS) who underwent endoscopic sinus surgery were recruited. Clinical features, CT evaluation, pre and postoperative SNOT-22 scores and histopathologic findings were collected. Tissue eosinophils and mucosal remodeling were analyzed relative to clinical features and outcomes 12 months postoperatively.

RESULTS

Symptom improvement was seen for the entire population. Eosinophilic CRS had significantly worse preoperative and postoperative SNOT-22 scores than non- eosinophilic CRS. Symptom improvement in eosinophilic CRS after surgery was less than that of non-eosinophilic CRS. There was no significant association between preoperative and postoperative SNOT-22 scores and remodeling markers. However, patients with basement membrane thickening showed less reductions of SNOT-22 score postoperatively.

CONCLUSIONS

Presence of mucosal eosinophilia and basal membrane thickening appear to be the main factors adversely affect the symptom control of surgical intervention. Routine histopathology analysis can provide meaningful information for prognostication of surgical outcome.

Immunological Characteristics in Refractory Chronic Rhinosinusitis with Nasal Polyps Undergoing Revision Surgeries

Purpose

Despite medical and surgical treatments, some cases of nasal polyps (NP) exhibit recidivism. However, the endotype of refractory chronic rhinosinusitis with NP (CRSwNP) remains unclear. Therefore, the objective of this study was to characterize the immunological profile of refractory CRSwNP.

Methods

The control (n =23), primary NP group (pNP, n =70) and refractory NP group (rNP, n =86) were enrolled in this study. Patients who underwent revision surgeries due to failed maximal medical treatment after primary surgery were defined as the rNP group. A total of 18 inflammatory markers were investigated in nasal tissues using multiplex cytokine assay or enzyme-linked immunosorbent assay.

Results

The clinical characteristics of rNP included more extensive disease and worse clinical course after surgery. Additionally, rNP subjects showed higher infection rate (mucopurulence and culture-positive rate), more frequent use of antibiotics and suffered from symptomatic bacterial infection, increased asthma morbidity compared to pNP. Cytokine profile analysis showed that levels of Th17-associated mediators (myeloperoxidase, interleukin (IL)-8, IL-17A and IL-23), B-cell activating factor (BAFF) and Th1 cytokine (interferon-γ) were up-regulated in rNP compared to controls and pNP. Human neutrophil elastase-positive cells were also enhanced in rNP compared with pNP. Upregulation of Th17/Th1mediators and BAFF were observed in rNP, regardless of tissue eosinophilia or asthmatic comorbidity. Interestingly, eosinophilic markers, such as eosinophil cationic protein and C-C motif chemokine ligand 24, were up-regulated in asthmatic rNP compared to pNP and controls. Levels of anti-dsDNA immunoglobulin (Ig) G and IgA were up-regulated in rNP and highest in asthmatic eosinophilic rNP among subtypes of rNP.

Conclusions

Our results suggest that Th17/Th1-associated mediators and BAFF may play a role and be a potential therapeutic target in refractory CRSwNP. Additionally, eosinophilic markers and autoantibodies may contribute to refractoriness in asthmatic rNP.

Local IL-25 contributes to Th2-biased inflammatory profiles in nasal polyps

BACKGROUND

IL-25 has been proposed to play a key role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). This study aimed to evaluate the association of IL-25 with the Th2-biased inflammatory profiles in CRSwNP.

METHODS

Nasal polyp (NP) tissues and control uncinate process tissues were collected from 92 patients with CRSwNP, 20 patients with chronic rhinosinusitis without nasal polyps (CRSsNP), and 16 normal control subjects. IL-25 expression was examined using immunohistochemistry and immunofluorescence staining, flow cytometry, RT-qPCR, and ELISA. The inflammatory profiles and clinical characteristics of 2 NP subtypes (IL-25^high and IL-25^low ) were evaluated, and the effects of IL-25 on Th2 cytokine production in cultured dispersed polyp cells were examined in vitro.

RESULTS

The mRNA and protein levels of IL-25 were significantly increased in the polyp tissues compared with the control uncinate process tissues. The IL-25^high subtype showed greater computed tomography scores, endoscopic scores, and Th2 response. Exposure to IL-25 activated type 2 innate lymphoid cells and Th2 cells in NP simultaneously which further increased Th2 cytokine production in vitro.

CONCLUSIONS

Local IL-25 plays a crucial role in promoting Th2-biased inflammatory profiles in NP and may serve as a promising therapeutic target in CRSwNP patients.

The role of cysteinyl leukotrienes and their receptors in refractory nasal polyps

Leukotriene signaling is essential in many diseases, including asthma, allergic rhinitis, atherosclerosis and inflammatory bowel disease. Nevertheless, the expression of cysteinyl leukotrienes (CysLTs) and its receptors (CYSLTRs) in different types of nasal polyps (NPs), and the role of their antagonist in the treatment of refractory chronic rhinosinusitis with nasal polyps (CRSwNP) are not well understood. The following study investigates the expression of CysLTs and CYSLTRs in different types of NPs, as well as the role of leukotriene receptor antagonist (montelukast) in refractory NPs. Our data showed that CysLTs and CYSLTRs were significantly elevated in CRSwNP group (p < 0.05), particularly in IL-5⁺NP patients^, compared to patients with chronic rhinosinusitis but without NPs (CRSsNP) and the control group. Furthermore, montelukast have shown the ability to inhibit the expression of MUC5AC, TSLP, IL-4, IL-5, IL-13, and TGF-β in NP explants after treatment with Staphylococcal Enterotoxins B (SEB). In addition, the patients treated by additional montelukast have better outcomes compared to those with INCS only. To conclude, our results demonstrate that the inhibition of CysLTs signaling by montelukast decreases the expression of cytokines and mucin in polyp explants, and in turn promotes the recovery in patients with refractory CRSwNP.

Inflammatory infiltrate and mucosal remodeling in chronic rhinosinusitis with and without polyps: structured histopathologic analysis

BACKGROUND

Chronic rhinosinusitis (CRS) is commonly classified into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Structured histopathologic reporting has the potential to identify salient histologic markers to differentiate subtypes and provide insights into pathophysiologic mechanisms in CRS.

METHODS

A structured histopathology report of 13 variables was prospectively employed to analyze ethmoid sinus tissue removed during endoscopic sinus surgery for 99 patients, including 43 CRSsNP and 56 CRSwNP. These variables were compared in association with presence of nasal polyps, radiographic computed tomography scores (Lund-Mackay Score [LMS]), subjective symptoms scores (SNOT-22), duration of CRS, comorbid asthma, and atopy.

RESULTS

Overall inflammation did not differentiate between CRSsNP and CRSwNP (p < 0.26). Compared to CRSsNP, CRSwNP had statistically significant increase in basement membrane thickening (76.8% vs 48.8%, p < 0.004), subepithelial edema (19.6% vs 2.3%, p < 0.01), fibrosis (58.9% vs 27.9%, p < 0.002), hyperplastic/papillary changes (12.5% vs 0.0%, p < 0.016), eosinophilia (41.1% vs 18.6%, p < 0.047), and eosinophilic aggregates (30.4% vs 11.6%, p < 0.022). Higher LMS was associated with increased eosinophilia (p < 0.001), eosinophil aggregates (p < 0.000), inflammation (p < 0.023), basement membrane thickening (p < 0.037), hyperplastic/papillary changes (p < 0.040) and fibrosis (p < 0.000). SNOT-22 scores were not associated with any histologic parameters.

CONCLUSION

Significant histopathologic differences were evident in patients with CRSwNP and CRSsNP. No single feature reliably differentiated between the 2 subtypes, underscoring the heterogeneity of CRS and limitation of this phenotypic classification system. Eosinophilic aggregates were associated with significantly worse disease, possibly signifying a unique subtype. Further studies are needed to understand the relationship of histopathologic features to disease outcome.

Th17 Cytokines Disrupt the Airway Mucosal Barrier in Chronic Rhinosinusitis

Cytokine mediated changes in paracellular permeability contribute to a multitude of pathological conditions including chronic rhinosinusitis (CRS). The purpose of this study was to investigate the effect of interferons and of Th1, Th2, and Th17 cytokines on respiratory epithelium barrier function. Cytokines and interferons were applied to the basolateral side of air-liquid interface (ALI) cultures of primary human nasal epithelial cells (HNECs) from CRS with nasal polyp patients. Transepithelial electrical resistance (TEER) and permeability of FITC-conjugated dextrans were measured over time. Additionally, the expression of the tight junction protein Zona Occludens-1 (ZO-1) was examined via immunofluorescence. Data was analysed using ANOVA, followed by Tukey HSD post hoc test. Our results showed that application of interferons and of Th1 or Th2 cytokines did not affect the mucosal barrier function. In contrast, the Th17 cytokines IL-17, IL-22, and IL-26 showed a significant disruption of the epithelial barrier, evidenced by a loss of TEER, increased paracellular permeability of FITC-dextrans, and discontinuous ZO-1 immunolocalisation. These results indicate that Th17 cytokines may contribute to the development of CRSwNP by promoting a leaky mucosal barrier.