Basophils are elevated in nasal polyps of patients with chronic rhinosinusitis without aspirin sensitivity

Correlation between peripheral blood basophils and chronic sinusitis with nasal polyps in different age groups

PURPOSE

Despite improved surgical and medical therapies, it remains a disease entity that is difficult to cure chronic rhinosinusitis with nasal polyps (CRSwNP), given a recently-reported incidence up to 4% of the population severely affects patients' quality of life. In this retrospective study, we attempted to assess the role of another important inflammatory cell, the blood basophil, in a large series of patients with CRSwNP (n = 316) across three different age groups.

METHODS

The investigation concerned 316 consecutive patients undergoing endoscopic sinus surgery (ESS) for CRSwNP. We divided these patients into three groups according to age, of which, 46 consecutive geriatric patients ( ≧ 61y), 243 consecutive young adult CRSwNP patients (19-60y), and 27 pediatric patients (≤ 18y) were enrolled.

RESULTS

Compared between groups, WBC and eosinophil counts in peripheral blood were not statistically different among the three groups, while blood basophil (p = 0.016), lymphocyte (p < 0.001), monocyte (p = 0.031) counts and LM scores (p = 0.025) were statistically different between groups, all of which were significantly different between pediatric and adult groups, pediatric and elderly groups. Spearman correlation analysis revealed blood basophil counts were positively correlated with blood eosinophils, leukocytes, lymphocytes, monocyte counts, and LM scores overall in the sample as a whole (p < 0.001).

CONCLUSION

The heterogeneous role of blood basophils identified in different age sub-cohorts of CRSwNP supports the hypothesis that blood basophil count may reflect the severity of inflammation in CRSwNP patients. In addition, we should pay attention to the long-term follow-up of pediatric patients with CRSwNP.

Endotyping in Chronic Rhinosinusitis-An EAACI Task Force Report

Chronic rhinosinusitis (CRS) is a clinical syndrome defined by typical sinonasal symptoms persisting for at least 12 weeks. CRS is divided into two distinct phenotypes, CRS with nasal polyps (CRSwNP) and without (CRSsNP). The aim of the review is to provide an update on the current knowledge in CRS endotypes. The prevailing hypothesis regarding the pathogenesis of CRS suggests that dysfunctional interactions between the host and environmental stressors at the mucosal surface drive the diverse inflammatory mechanisms. Genetic and epigenetic variations in the mucosal immune system are believed to play a significant role in the pathomechanisms of CRS. Various environmental agents (such as microbes and irritants) have been implicated in CRS. In a healthy state, the sinonasal mucosa acts as a barrier, modulating environmental stimulation and mounting appropriate immune responses against pathogens with minimal tissue damage. Different endotypes may exist based on the specific mechanistic pathways driving the chronic tissue inflammation of CRS. There is a need to understand endotypes in order to better predict, diagnose, and treat CRS. This literature review provides an update on the role of the endotypes in CRS and the limitations of endotyping CRS in clinical practice. Understanding of the pathogenesis and optimal management of CRS has progressed significantly in the last decades; however, there still are several unmet needs in endotype research.

Biologics in Chronic Rhinosinusitis: Current and Emerging

Chronic rhinosinusitis (CRS) is categorized phenotypically into CRS with and without nasal polyps (CRSwNP, CRSsNP). Endotyping categorizes the disease based on immune cell activity and inflammatory mechanisms into Type 1, Type 2, and Type 3. The Type 2 endotype is the most researched and associated with asthma, atopic disease, and severe CRSwNP. For patients with poorly controlled CRSwNP, there are 3 approved biologic treatments: omalizumab, dupilumab, and mepolizumab. Many other biologics are being tested in Type 2, non-Type 2, and mixed endotypes in CRSwNP and CRSsNP. These studies will play a significant role in shaping the future of CRS management.

Pharmacokinetics/pharmacodynamics of benralizumab in chronic rhinosinusitis with nasal polyps: Phase III, randomized, placebo-controlled OSTRO trial

AIMS

Benralizumab, a humanized, afucosylated monoclonal antibody against the interleukin 5 receptor, α subunit, causes rapid depletion of eosinophils by antibody-dependent cellular cytotoxicity. We investigated the pharmacokinetic and pharmacodynamic effects of benralizumab in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) from the phase III OSTRO trial.

METHODS

Patients received a placebo or 30 mg of benralizumab by subcutaneous injection every 8 weeks (first three doses every 4 weeks) to week 48; a subset of patients continued in an extended follow-up period to assess treatment durability to week 80. Serum benralizumab concentrations and blood eosinophil and basophil counts were assessed to week 80. Biomarker assessments were performed on nasal polyp tissue biopsies at week 56 and nasal lining fluid at weeks 24 and 56 to examine changes in immune cells and inflammatory mediators.

RESULTS

Among 185 patients in this analysis, 93 received benralizumab. Serum benralizumab concentrations reached a steady state by week 24 (median concentration 385.52 ng mL-1); blood eosinophils were almost fully depleted and blood basophils were reduced between weeks 16 and 56. Nasal polyp tissue eosinophils decreased with benralizumab from 57.6 cells mm-2 at baseline to 0 cells mm-2 at week 56 (P < .001 vs placebo), and tissue mast cells were numerically reduced. In nasal lining fluid, eosinophil-derived neurotoxin was significantly reduced at weeks 24 and 56 (P < .001) and interleukin-17 at week 56 (P < .05) with benralizumab.

CONCLUSION

Benralizumab treatment led to rapid, sustained, nearly complete depletion of eosinophils from blood and nasal polyp tissue in patients with CRSwNP.

Prevalence of Laryngopharyngeal Reflux Related Symptoms in Patients With Allergy

OBJECTIVE

To describe the prevalence of laryngopharyngeal reflux (LPR)-related symptoms in allergy patient using the Reflux Symptom Index (RSI) by Belafsky et al and the Reflux Symptom Score (RSS) by Lechien et al. SUBJECTS AND METHODS: A total of 84 patients were enrolled in this study. Fifty-two consecutive patients were asked to fill RSI. Similarly, 32 patients were asked to fill RSS. Demographic data included age, gender, history of smoking, family history for eczema, atopy, asthma, food and drug allergy.

RESULTS

Fifty-seven of the 84 patients were positive for at least one allergen and hence were diagnosed with allergy. Of the 52 patients who received the RSI, 36 patients were allergic to at least one allergen (36/52). Of the 32 patients who filled the RSS, 21 tested positive for at least one allergen (21/32). There was no significant difference in the number of positive RSI scores (>13) between patients with allergy to at least one allergen in comparison to patients with no allergy (P = 0.329). There was a significant difference in the number of positive RSS scores (>13) between patients with allergy to at least one allergen in comparison to patients with no allergy (P-value 0.0345). The odds of having RSS >13 in an allergic patient was significant (OR = 5.6, CI 95% = 1.15-27.37).

CONCLUSION

The results of this study provide evidence that patients with allergy have increased incidence of LPR related symptoms using the RSS. The cross-cutting in the clinical picture of patients with allergy and LPR stresses the need for objective testing such as double probe Ph-metry and impedance to diagnose this latter. Future studies are needed to explore further the cause-effect relationship between allergy and LPR.

Neuroimmune interplay during type 2 inflammation: Symptoms, mechanisms, and therapeutic targets in atopic diseases

Type 2 inflammation is characterized by overexpression and heightened activity of type 2 cytokines, mediators, and cells that drive neuroimmune activation and sensitization to previously subthreshold stimuli. The consequences of altered neuroimmune activity differ by tissue type and disease; they include skin inflammation, sensitization to pruritogens, and itch amplification in atopic dermatitis and prurigo nodularis; airway inflammation and/or hyperresponsiveness, loss of expiratory volume, airflow obstruction and increased mucus production in asthma; loss of sense of smell in chronic rhinosinusitis with nasal polyps; and dysphagia in eosinophilic esophagitis. We describe the neuroimmune interactions that underlie the various sensory and autonomic pathologies in type 2 inflammatory diseases and present recent advances in targeted treatment approaches to reduce type 2 inflammation and its associated symptoms in these diseases. Further research is needed to better understand the neuroimmune mechanisms that underlie chronic, sustained inflammation and its related sensory pathologies in diseases associated with type 2 inflammation.

S. aureus biofilm metabolic activity correlates positively with patients' eosinophil frequencies and disease severity in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a persistent inflammation of the sinus mucosa. Recalcitrant CRS patients are unresponsive to medical and surgical interventions and often present with nasal polyps, tissue eosinophilia, and Staphylococcus aureus dominant mucosal biofilms. However, S. aureus sinonasal mucosal colonisation occurs in the absence of inflammation, questioning the role of S. aureus in CRS pathogenesis. Here, we aimed to investigate the relationship between S. aureus biofilm metabolic activity and virulence genes, innate immune cells, and disease severity in CRS. Biospecimens, including sinonasal tissue and nasal swabs, and clinical datasets, including disease severity scores, were obtained from CRS patients and non-CRS controls. S. aureus isolates were grown into biofilms in vitro, characterised, and sequenced. The patients' innate immune response was evaluated using flow cytometry. S. aureus was isolated in 6/19 (31.58%) controls and 23/53 (43.40%) CRS patients of 72 recruited patients. We found increased S. aureus biofilm metabolic activity in relation to increased eosinophil cell frequencies and disease severity in recalcitrant CRS cases. Mast cell frequencies were higher in tissue samples of patients carrying S. aureus harbouring lukF.PV, sea, and fnbB genes. Patients with S. aureus harbouring lukF.PV and sdrE genes had more severe disease. This offers insights into the pathophysiology of CRS and could lead to the development of more targeted therapies.

Unraveling the Role of Epithelial Cells in the Development of Chronic Rhinosinusitis

The pathophysiology of CRS is multifactorial and complex yet needs to be completed. Recent evidence emphasizes the crucial part played by epithelial cells in the development of CRS. The epithelial cells act as physical barriers and play crucial roles in host defense, including initiating and shaping innate and adaptive immune responses. This review aims to present a comprehensive understanding of the significance of nasal epithelial cells in CRS. New research suggests that epithelial dysfunction plays a role in developing CRS through multiple mechanisms. This refers to issues with a weakened barrier function, disrupted mucociliary clearance, and irregular immune responses. When the epithelial barrier is compromised, it can lead to the passage of pathogens and allergens, triggering inflammation in the body. Furthermore, impaired mucociliary clearance can accumulate pathogens and secretions of inflammatory mediators, promoting chronic inflammation. Epithelial cells can release cytokines and chemokines, which attract and activate immune cells. This can result in an imbalanced immune response that continues to cause inflammation. The interaction between nasal epithelial cells and various immune cells leads to the production of cytokines and chemokines, which can either increase or decrease inflammation. By comprehending the role of epithelial cells in CRS, we can enhance our understanding of the disease's pathogenesis and explore new therapeutics.

Aspirin-exacerbated respiratory disease: Updates in the era of biologics

OBJECTIVE

Aspirin-exacerbated respiratory disease (AERD) is a chronic respiratory condition characterized by severe chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic asthma, and respiratory reactions to cyclooxygenase inhibitors. The management of AERD has evolved recently with the availability of respiratory biologics for treatment of severe asthma and CRSwNP. The objective of this review is to provide an update on the management of AERD in the era of respiratory biologic therapy.

DATA SOURCES

A literature review of pathogenesis and treatment of AERD, with a specific focus on biologic therapies in AERD, was performed through publications gathered from PubMed.

STUDY SELECTIONS

Original research, randomized controlled trials, retrospective studies, meta-analyses, and case series of high relevance are selected and reviewed.

RESULTS

Aspirin therapy after desensitization (ATAD) and respiratory biologic therapies targeting interleukin (IL)-4Rα, IL-5, IL-5Rα, and immunoglobulin E, all have some efficacy in the treatment of CRSwNP and asthma in patients with AERD. There are currently no head-to-head studies comparing ATAD vs respiratory biologic therapy, or specific respiratory biologics, for asthma and CRSwNP in patients with AERD.

CONCLUSION

Advances in our understanding of the fundamental drivers of the chronic respiratory inflammation in asthma and CRSwNP have led to the identification of several potential therapeutic targets for these diseases that can be used in patients with AERD. Further study of the use of ATAD and biologic therapy, independently and together, will help to inform future treatment algorithms for patients with AERD.

Mechanistic and clinical updates in AERD: 2021-2022

Aspirin-exacerbated respiratory disease (AERD) is a unique and often clinically severe disease affecting a subgroup of adults with asthma and chronic rhinosinusitis with nasal polyposis. Works published in 2021-2022 confirmed the critical role of lipid mediator dysregulation and mast cell activation and expanded our understanding of basophils, macrophages, fibrin dysregulation, and the 15-lipoxygenase pathway in disease pathogenesis. Translational studies established inflammatory heterogeneity in the upper and lower airway at baseline and during aspirin-induced respiratory reactions. Clinical cohorts provided insights into the mechanistic actions of frequently utilized biologic therapies in AERD. These advances are already changing clinical care delivery and affecting patient outcomes. Despite this, further work is needed to improve clinical tools to reliably diagnose AERD and identify factors that could prevent development of the disease altogether. Additionally, the impact of inflammatory heterogeneity on clinical trajectories and the utility and safety of combination biologic and daily aspirin therapies remains unanswered.

Blood Basophils Relevance in Chronic Rhinosinusitis with Aspirin-Exacerbated Respiratory Disease

Aspirin-exacerbated respiratory disease (AERD) is characterized by eosinophilic asthma, chronic rhinosinusitis with nasal polyps (CRSwNP) and intolerance to cyclooxygenase-1 inhibitors. Interest is emerging in studying the role of circulating inflammatory cells in CRSwNP pathogenesis and its course, as well as their potential use for a patient-tailored approach. By releasing IL-4, basophils play a crucial role in activating the Th2-mediated response. The main aim of this study was to, first, investigate the level of the pre-operative blood basophils' values, blood basophil/lymphocyte ratio (bBLR) and blood eosinophil-to-basophil ratio (bEBR) as predictors of recurrent polyps after endoscopic sinus surgery (ESS) in AERD patients. The secondary aim was to compare the blood basophil-related variables of the AERD series (study group) with those of a control group of 95 consecutive cases of histologically non-eosinophilic CRSwNP. The AERD group showed a higher recurrence rate than the control group (p < 0.0001). The pre-operative blood basophil count and pre-operative bEBR were higher in AERD patients than in the control group (p = 0.0364 and p = 0.0006, respectively). The results of this study support the hypothesis that polyps removal may contribute to reducing the inflammation and activation of basophils.

[Correlation between chronic sinusitis subtypes and basophil levels in peripheral blood]

Objective:To explore the clinical correlation between peripheral blood basophil levels and chronic sinusitis （CRS） subtypes. Methods:One hundred and twenty-six patients with CRS and 103 healthy cases from physical examination admitted to the First Affiliated Hospital of Soochow University from January 2021 to October 2022 were retrospectively analyzed. According to the histopathological classification, CRS patients were divided into eosinophilic chronic sinusitis （eCRS） group （47 cases） and non eosinophilic chronic sinusitis （non-eCRS） group （79 cases）. The differences among the three groups in peripheral blood inflammation cell counts, eosinophils-to-basophils ratio（bEBR）, basophils-to-neutrophils ratio（BNR）, basophils-to-lymphocytes ratio（BLR）, basophils-to-monocytes ratio（BMR） were compared, and study the correlation between each index and Lund-Mackay score, and the correlation between basophils in peripheral blood and other inflammatory cells. Results:The counts of basophils in the peripheral blood of the healthy control group, eCRS group and non-eCRS group were 0.03±0.01, 0.04±0.02, 0.03±0.02, respectively, the eosinophils-to-basophils ratio（bEBR） were 5.64±4.22, 8.38±5.95, 4.55±3.90, the basophils-to-neutrophils ratio（BNR） were 0.01±0, 0.01±0.01, 0.01±0.01, and the basophils-to-lymphocytes ratio（BLR） were 0.01±0.01, 0.02±0.01, and 0.02±0.01, respectively, the basophils-to-monocytes ratio（BMR） were 0.08±0.04, 0.11±0.06, and 0.08 ±0.04 respectively. There was a statistically significant difference between eCRS group and healthy control group, non-eCRS group（P<0.01）, while there was no statistically significant difference between non-eCRS group and healthy control group（P>0.05）. Basophil counts （r=0.185 5, P<0.05）, BLR（r=0.226 9, P<0.05）, BMR（r=0.228 1, P<0.01） in patients with CRS were positively correlated with Lund Makey score. In addition, basophils were also positively correlated with eosinophils（r=0.479 2, P<0.01）, lymphocytes（r=0.259 4, P<0.01）, and monocytes（r=0.256 4, P<0.01） in patients with CRS. Conclusion:The peripheral blood basophil count, BLR and BMR were significantly increased in eCRS, and were significantly positively correlated with Lund -Makey score. It has the potential to develop into disease biomarkers and new therapeutic targets of eCRS.

Pathogenesis of Nasal Polyposis: Current Trends

Chronic Rhinosinusitis (CRS) is characterized by edema of the sub-epithelial layers, but, only specific types of CRS are developing polyps. Nasal polyposis may develop under different pathogenetic mechanisms rendering the typical macroscopic classification of CRS, with or without nasal polyps, rather deficient. Currently, we approach nasal polyposis, in terms of diagnosis and treatment, according to its endotype, which means that we focus on the specific cells and cytokines that are participating in its pathogenesis. It appears that the molecular procedures that contribute to polyp formation, initiating with a Th-2 response of the adaptive immune system, are local phenomena occurring in the sub-epithelial layers of the mucosa. Several hypotheses are trying to approach the etiology that drives the immune response towards Th-2 type. Extrinsic factors, like fungi, Staphylococcus superantigens, biofilms, and altered microbiome can contribute to a modified and intense local reaction of the immune system. Some hypotheses based on intrinsic factors like the elimination of Treg lymphocytes, low local vitamin-D levels, high levels of leukotrienes, epithelial to mesenchymal transition (EMT) induced by hypoxia, and altered levels of NO, add pieces to the puzzle of the pathogenesis of nasal polyposis. Currently, the most complete theory is that of epithelial immune barrier dysfunction. Intrinsic and extrinsic conditions can damage the epithelial barrier rendering sub-epithelial layers more vulnerable to invasion by pathogens that trigger a Th-2 response of the adaptive immune system. Th2 cytokines, subsequently, induce the accumulation of eosinophils and IgE together with the remodeling of the stroma in the sub-epithelial layers leading, eventually, to the formation of nasal polyps.

Endotyping Chronic Rhinosinusitis with Nasal Polyps: Understanding Inflammation Beyond Phenotypes

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a heterogenous group of inflammatory conditions impacting the nose and paranasal sinuses. Our understanding of the underlying pathobiology of CRSwNP has substantially improved due to ongoing translational research efforts. Advances in treatment options, including targeted respiratory biologic therapy for CRSwNP, allow for more personalized approaches for CRSwNP patient care. Patients with CRSwNP are typically classified to one or more endotype based on the presence of type 1, type 2, and type 3 inflammation. This review will discuss recent advances in our understanding of CRSwNP and how this may impact current and future treatment approaches for patients with CRSwNP.

Atopic dermatitis and risk of gastroesophageal reflux disease: A nationwide population-based study

BACKGROUND

As atopic dermatitis (AD) has been found to be related to various comorbidities as well as substantial patient burden, questions of a possible relationship between AD and nonallergic diseases beyond allergic diseases have also been raised.

OBJECTIVE

The aim of this nationwide matched cohort study was to evaluate whether AD would increase the development of gastroesophageal reflux disease (GERD).

METHODS

Patients diagnosed with AD were identified from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) 2.0 database in South Korea from 2002 to 2015. Finally, 9,164 adults with AD (≥20 years old) and age, sex, household income, region of residence, disability, and baseline year-matched 9,164 controls were included in the analysis. Hazard ratio (HR) with 95% confidence interval (CI) for the development of GERD was estimated using a Cox proportional hazard regression model.

RESULTS

Overall, 12.3% of the patients in the AD group developed GERD, whereas 10.4% of the individuals in the control group developed GERD. The results of the adjusted model revealed that patients with AD had a significantly increased risk of developing GERD (adjusted HR, 1.15; 95% CI, 1.06-1.26) compared with the matched controls. Increased risk of developing GERD was consistent in subgroup analyses by sex or age groups under 60 years old as well as all the sensitivity analyses performed.

CONCLUSIONS

This study suggested that appropriate management should be considered in adults with AD to prevent GERD, because AD was found to be associated with an increased risk of subsequent GERD.

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

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

Role of Basophils in a Broad Spectrum of Disorders

Basophils are the rarest granulocytes and have long been overlooked in immunological research due to their rarity and similarities with tissue-resident mast cells. In the last two decades, non-redundant functions of basophils have been clarified or implicated in a broad spectrum of immune responses, particularly by virtue of the development of novel analytical tools for basophils. Basophils infiltrate inflamed tissues of patients with various disorders, even though they circulate in the bloodstream under homeostatic conditions. Depletion of basophils results in the amelioration or exaggeration of inflammation, depending on models of disease, indicating basophils can play either beneficial or deleterious roles in a context-dependent manner. In this review, we summarize the recent findings of basophil pathophysiology under various conditions in mice and humans, including allergy, autoimmunity, tumors, tissue repair, fibrosis, and COVID-19. Further mechanistic studies on basophil biology could lead to the identification of novel biomarkers or therapeutic targets in a broad range of diseases.

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.

Elevated Serum Leptin Levels in Patients With Eosinophilic Chronic Rhinosinusitis

Background: Eosinophilic chronic sinusitis (ECRS) is a subtype of CRS with nasal polyps (CRSwNP) that is frequently comorbid with asthma. Notably, ECRS patients often show a high recurrence of NPs after surgical resection. Leptin is a hormone produced by adipocytes that has been implicated in airway inflammatory diseases. However, to date, the role of leptin in ECRS has not been investigated. Objective: To determine whether the serum levels of leptin are altered in patients with ECRS. Methods: In total, 40 patients with ECRS, 15 patients with non-eosinophilic CRS (non-ECRS), and 12 individuals without CRS (control) were included in this study. Patient's serum leptin levels were assessed, and the number of eosinophils in their NPs were measured through a histological evaluation of the three densest areas with cellular infiltrate beneath the epithelial surface. Finally, nasal fibroblast cultures established from NPs were stimulated with varying concentrations of recombinant leptin in vitro to determine whether leptin affects eotaxin-3 (Chemokine (C-C motif) ligand 26 :26: CCL26) expression. Results: The serum leptin levels in both the ECRS and non-ECRS groups were significantly higher than those in the control subjects (p < 0.0001 vs. ECRS; p < 0.05 vs. non-ECRS). Furthermore, ECRS patients displayed significantly elevated serum leptin levels compared to non-ECRS patients (p < 0.001), although there was no difference in body mass index between the groups. Notably, serum leptin levels were correlated with the proportion of eosinophils in peripheral blood (r = 0.3575, p < 0.01) and the number of eosinophils in NPs (r = 0.5109, p < 0.0001). Serum leptin levels were also correlated with eotaxin-3 mRNA expression in NPs (r = 0.5374, p < 0.01). Finally, leptin significantly augmented eotaxin-3 expression in nasal fibroblasts established in vitro from NPs in a leptin receptor-dependent manner (p < 0.05). Conclusion: Leptin levels are elevated in ECRS patients and may both promote and indicate the severity of ECRS as well as systemic type 2-biased inflammatory responses. Combined, these data indicate that circulating leptin may play a significant role in the development of eosinophilic inflammation in NPs.

Pathophysiological and Clinical Aspects of Chronic Rhinosinusitis: Current Concepts

Adult chronic rhinosinusitis (CRS) is a chronic inflammation of the mucosa of the nose and paranasal sinuses. According to the latest EPOS guidelines CRS should be regarded as primary or secondary with distinction between diffuse and localized disease. Further pathophysiologic research identified different inflammatory patterns leading to the term “endotyping of CRS.” The primary focus of endotyping is to define a dominant inflammatory type allowing for better orientation of therapy. The current approach proposes the differentiation between type 2 (eosinophilic) and non-type 2 inflammatory responses. In this review pathophysiological concepts of CRS will be discussed, focusing on the different inflammatory endotypes of T cells with special attention to the eosinophilic type 2 inflammatory response. The contribution of innate and adaptive immune system responses is presented. The possibility of endotyping based on sinonasal secretions sampling is brought to attention because it is indicative of corticosteroid responsiveness and available to most ENT surgeons. Furthermore, the clinical aspects of the three distinct phenotypes are analyzed in view of their characteristics, the related endoscopic findings, typical radiological imaging, histopathology findings, their relation toward allergy and obvious therapeutical implications. This overview will enable clinicians to relate pathophysiological patterns with clinical observations by explaining the different inflammatory mechanisms, hence providing a better understanding of therapy.

Yardstick for the medical management of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is an inflammatory condition of the paranasal sinuses defined by classic symptoms, imaging findings, or endoscopic findings. There are a growing number of emerging pharmacologic therapies being evaluated to treat patients with CRS, some of which have gained indication status in the United States. There have not been updated treatment guidelines published in the United States however since 2014. This document is meant to serve as an updated expert consensus document for the pharmacologic management of patients with CRS. We review available data focusing on prospective clinical trials on oral and intranasal corticosteroids, nasal irrigation, biologics, antibiotics, and allergy immunotherapy for CRS both with and without nasal polyposis, including specific therapies for aspirin-exacerbated respiratory disease-associated CRS and allergic fungal CRS. There are multiple options to treat CRS, and clinicians should be knowledgeable on the efficacy and risks of these available therapies. Allergists-immunologists now have various therapies available to treat patients with CRS.

Innate immune cell dysregulation drives inflammation and disease in aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is a complex inflammatory disorder that is not generally viewed as a disease involving the adaptive immune system but instead one largely driven by the innate immune system. This article focuses on the cellular dysregulation involving 4 central cell types: eosinophils, basophils, mast cells, and innate lymphoid type 2 cells. AERD can be envisioned as involving a self-perpetuating vicious circle in which mediators produced by a differentiated activated epithelial layer, such as IL-25, IL-33, and thymic stromal lymphopoietin, engage and activate each of these innate immune cells. The activation of these innate immune cells with their production of additional cytokine/chemokine and lipid mediators leads to further recruitment and activation of these innate immune cells. More importantly, numerous mediators produced by these innate immune cells provoke the epithelium to induce further inflammation. This self-perpetuating cycle of inflammation partially explains both current interventions suggested to ameliorate AERD (eg, aspirin desensitization, leukotriene modifiers, anti-IL-5/IL-5 receptor, anti-IL-4 receptor, and anti-IgE) and invites exploration of novel targets as specific therapies for this condition (prostaglandin D₂ antagonists or cytokine antagonists [IL-25, IL-33, thymic stromal lymphopoietin]). Several of these interventions currently show promise in small retrospective analyses but now require definite clinical trials.

A murine model of eosinophilic chronic rhinosinusitis using the topical application of a vitamin D3 analog

BACKGROUND

Eosinophilic chronic rhinosinusitis (ECRS) is a chronic inflammatory disease, characterized by eosinophilic infiltration, T-helper type 2 (Th2-type) response, and olfactory dysfunction. A master regulator of Th2-type inflammation, thymic stromal lymphopoietin (TSLP), is important for basophil activation. TSLP-elicited basophils are a key factor in the pathogenesis of ECRS.

METHODS

In order to elucidate the mechanisms of ECRS in humans, we aimed to establish a murine model of ECRS based on TSLP production in response to the topical application of MC903 (a vitamin D3 analog) and the subsequent TSLP-induced basophil activation. Histological analyses were performed to assess immune cell infiltration into the nasal mucosa and to explore the impact of eosinophilic inflammation on the olfactory epithelium. The status of Th2-type inflammation was evaluated by quantitative real-time PCR and enzyme-linked immunosorbent assay (ELISA).

RESULTS

Eosinophils, basophils, and M2 macrophages increased significantly in the nasal mucosa of the mice treated with MC903 and ovalbumin (OVA), compared to those treated with OVA alone or the controls. Quantitative real-time PCR and ELISA revealed elevated expression of interleukin (IL)-4, IL-5, IL-13, TSLP, the chemokine CCL11, and CCL24 in the nasal mucosa of the ECRS mice. In parallel, thinned olfactory epithelium and decreased mature olfactory sensory neurons were observed in the ECRS mice.

CONCLUSIONS

Our model of ECRS displayed Th2-type inflammation in the sinonasal region, including both eosinophil infiltration and basophil infiltration. Additionally, olfactory epithelium turned out to be affected by eosinophilic inflammation. These features are consistent with the characteristics of the human ECRS.

Studies of the role of basophils in aspirin-exacerbated respiratory disease pathogenesis

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is characterized by the triad of chronic rhinosinusitis with nasal polyps (CRSwNP), asthma, and intolerance to cyclooxygenase-1 enzyme inhibitors. The underlying mechanisms contributing to AERD pathogenesis are not fully understood, but AERD is characterized by an enhanced type 2 inflammatory phenotype. Basophils are potent type 2 effector cells, but their involvement in AERD pathophysiology remains unclear.

OBJECTIVE

We sought to characterize the systemic and local basophil responses in patients with AERD compared with patients with CRSwNP.

METHODS

Sinonasal tissues including inferior turbinate and/or nasal polyps (NPs) and peripheral blood were collected from controls, patients with AERD, and patients with CRSwNP. Expression of cell surface (CD45, FcεRI, CD203c), activation (CD63), and intracellular (2D7) markers associated with basophils was characterized using flow cytometry. Clinical data including Lund-Mackay scores and pulmonary function were obtained.

RESULTS

The mean number of basophils (CD45⁺CD203c⁺FcεRI⁺CD117^-) detected in AERD NPs (147 ± 28 cells/mg tissue) was significantly elevated compared with that detected in CRSwNP NPs (69 ± 20 cells/mg tissue; P = .01). The number of circulating basophils was significantly elevated in patients with AERD (P = .04). Basophils in NPs had significantly higher CD203c and CD63 mean fluorescence intensity compared with blood in both conditions (P < .01). Basophils from AERD NPs had lower expression of the granule content marker 2D7 compared with those from matched blood (P < .01) or NPs of patients with CRSwNP (P = .06), suggesting ongoing degranulation. Basophil 2D7 mean fluorescence intensity significantly correlated with pulmonary function (r = 0.62; P = .02) and inversely correlated with sinonasal inflammation (r = -0.56; P = .004).

CONCLUSIONS

Increased basophil numbers and extent of ongoing degranulation in NPs of patients with AERD compared with patients with CRSwNP may contribute to the exaggerated disease pathogenesis and severity unique to AERD.

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.

Targetable pathogenic mechanisms in nasal polyposis

Chronic rhinosinusitis with nasal polyps (CRSwNP) represents a challenging disease entity with significant rates of recurrence following appropriate medical and surgical therapy. Recent approval of targeted biologics in CRSwNP compels deeper understanding of underlying disease pathophysiology. Both of the approved biologics for CRSwNP modulate the type 2 inflammatory pathway, and the majority of drugs in the clinical trials pathway are similarly targeted. However, there remain multiple other pathogenic mechanisms relevant to CRSwNP for which targeted therapeutics already exist in other inflammatory diseases that have not been studied directly. In this article we summarize pathogenic mechanisms of interest in CRSwNP and discuss the results of ongoing clinical studies of targeted therapeutics in CRSwNP and other related human inflammatory diseases.

[Management strategies for chronic rhinosinusitis with nasal polyps in adults]

INTRODUCTION

Chronic rhinosinusitis with nasal polyps (CRSwNP) is one of the categories of chronic rhinosinusitis and is defined by the presence of bilateral polyps. It is frequently associated with other conditions (asthma, atopy, aspirin intolerance), which worsen its prognosis.

STATE OF ART

The pathophysiology of CRSwNP is still poorly understood. The genesis of polyps is thought to be based on an initial epithelial lesion caused by environmental factors in the context of self-maintained chronic local inflammation. Multiple local and general factors can be involved in this inflammation, which is mainly of Th2 type in Europe. Abnormalities of the epithelial barrier and the immune system (eosinophilia, cytokines, T and B lymphocytes), genetic factors and pathogens, including Staphylococcus aureus, have been incriminated. The treatment of CRSwNP is mainly based on the application of local corticosteroids. Surgery remains an important part of patient management where CRSwNP becomes resistant to topical therapy. The management of CRSwNP may be at a turning point thanks to the arrival of biological therapies (anti-IgE, anti-IL-5, anti-IL-4/IL-13) the initial results of which are promising.

PERSPECTIVES/CONCLUSIONS

With the new concept of endotypes, current avenues of research are moving towards a better understanding of the inflammatory mechanisms of CRSwNP. Immunotherapy appears to be a promising future for the treatment of CRSwNP.

Mechanisms and biomarkers of inflammatory endotypes in chronic rhinosinusitis without nasal polyps

BACKGROUND

Chronic rhinosinusitis (CRS) without nasal polyps (CRSsNP) is a common disease that is characterized by multiple inflammatory endotypes. However, the molecular mechanisms in CRSsNP are poorly understood compared with those of polypoid CRS.

OBJECTIVE

Our aim was to identify mechanisms and biomarkers associated with inflammatory endotypes underpinning CRSsNP.

METHODS

Ethmoid tissues and nasal lavage fluids (NLFs) were obtained from control patients and patients with CRS. The gene expression profiles were determined by microarray analysis and quantitative RT-PCR, and expression of proteins was measured by ELISA and Luminex analysis.

RESULTS

Microarray found that compared with their levels of expression in control tissue, the levels of expression of 126, 241, and 545 genes were more than 3-fold and significantly elevated in CRSsNP with type 1 (T1) endotype, type 2 (T2) endotype, and type 3 (T3) endotype, respectively. Selected identified genes were confirmed by RT-PCR. Gene set enrichment analysis suggested that T1 CRSsNP was associated with IFN-γ signaling and antiviral immunity controlled by T cells (T_H1 and CD8⁺), natural killer cells, and antigen-presenting cells; T2 CRSsNP was associated with STAT6 signaling and IgE-mediated activation controlled by eosinophils, mast cells, T_H2 cells, group 2 innate lymphoid cells, and antigen-presenting cells; and T3 CRSsNP was associated with IL-17 signaling, acute inflammatory response, complement-mediated inflammation, and infection controlled by neutrophils, T_H17 cells, B cells, and antigen-presenting cells. The results suggest that T1 (CXCL9 and CXCL10), T2 (eosinophilic proteins and CCL26), and T3 (CSF3) endotypic biomarkers in NLF may be able to distinguish tissue endotypes in CRSsNP.

CONCLUSIONS

Inflammatory endotypes in CRSsNP were controlled by different molecular mechanisms. NLF biomarker assays may allow for more precise and personalized medical treatments in CRS.

WITHDRAWN: Dupilumab: A review of potential in the treatment of Chronic rhinosinusitis with nasal polyps (CRSwNP)

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Allergic rhinitis as a key factor for the development of gastroesophageal reflux disease in children

BACKGROUND

Gastroesophageal reflux disease (GERD) may cause airway symptoms and some airway diseases exacerbate GERD symptoms. Asthma and allergic rhinitis (AR) have been identified as united airway disease because of their similar epidemiology and pathophysiology. Asthma has been considered a risk factor to develop GERD. However, the association between AR and GERD is not clear. We tried to investigate whether AR could increase the development of GERD.

METHODS

Children diagnosed as AR without a prior history of GERD were conducted from the National Health Insurance Research Database between 2000 and 2005. After propensity score matching, we enrolled 36,588 children with AR and 36,588 non-AR children as the controls. Cox regression models were adopted to calculate the hazard ratio (HR) of GERD.

RESULTS

AR children had a significantly increased risk of GERD than non-AR children (adjusted HR 1.91, 95% CI = 1.73-2.11, p < 0.001), especially in the age less than 6 years old (adjusted HR 2.68, 95% CI = 1.64-4.38, p < 0.001). The risk factor related to increased risk of GERD including age, gender, and chronic sinusitis.

CONCLUSION

AR is a risk factor associated with the development of GERD in children.

Chinese Society of Allergy and Chinese Society of Otorhinolaryngology-Head and Neck Surgery Guideline for Chronic Rhinosinusitis

The current document is based on a consensus reached by a panel of experts from the Chinese Society of Allergy and the Chinese Society of Otorhinolaryngology-Head and Neck Surgery, Rhinology Group. Chronic rhinosinusitis (CRS) affects approximately 8% of Chinese adults. The inflammatory and remodeling mechanisms of CRS in the Chinese population differ from those observed in the populations of European descent. Recently, precision medicine has been used to treat inflammation by targeting key biomarkers that are involved in the process. However, there are no CRS guidelines or a consensus available from China that can be shared with the international academia. The guidelines presented in this paper cover the epidemiology, economic burden, genetics and epigenetics, mechanisms, phenotypes and endotypes, diagnosis and differential diagnosis, management, and the current status of CRS in China. These guidelines-with a focus on China-will improve the abilities of clinical and medical staff during the treatment of CRS. Additionally, they will help international agencies in improving the verification of CRS endotypes, mapping of eosinophilic shifts, the identification of suitable biomarkers for endotyping, and predicting responses to therapies. In conclusion, these guidelines will help select therapies, such as pharmacotherapy, surgical approaches and innovative biotherapeutics, which are tailored to each of the individual CRS endotypes.

Persistence of Sinonasal Disease Despite Mepolizumab

The treatment paradigm for the management of chronic rhinosinusitis with nasal polyposis (CRSwNP) is currently undergoing a rapid evolution with the development of monoclonal antibody therapies targeted at type 2 inflammatory pathways. The use of these biologic therapies in asthmatic patients, and more recently, patients with CRSwNP has produced promising results, especially for patients with severe disease. Many questions regarding the appropriate timing of these medications, whether or not these new treatment strategies should be used as a monotherapy or in conjunction with traditional therapies such as sinus surgery, the role of appropriate phenotyping, and identification of biomarkers, remain unanswered. We herein present a case of a patient with severe eosinophilic asthma and comorbid CRSwNP who failed to achieve control of his respiratory symptomology and ultimately progressed to sinus surgery despite treatment with an anti-interleukin 5 monoclonal antibody therapy (mepolizumab). Consideration is given to the mechanistic underpinnings of the reported patient's failure. This case highlights the need for further understanding of the optimal usage of these novel therapeutics in the management of CRSwNP and in the need to better understand the pathophysiology of CRSwNP.

Efficacy of Budesonide Nasal Spray on Neutrophilic Chronic Rhinosinusitis with Nasal Polyps: A Combined Clinical and Experimental Study

BACKGROUND

Neutrophilic chronic rhinosinusitis with nasal polyps (CRSwNP) occur predominantly in Asian subjects. Appropriate treatments for this endotype have not been elucidated. This study aimed to evaluate the efficacy of budesonide nasal spray on neutrophilic CRSwNP.

MATERIALS AND METHODS

Fifteen neutrophilic CRSwNP patients were included, and then they received budesonide nasal spray treatment for 3 months. Biopsies of nasal polyps (NPs) were obtained from these subjects. Their clinical indexes were scored using Visual Analog Scale (VAS), Sino-Nasal Outcome Test (SNOT)-22, and Endoscopic Appearances (EAs). Histological analyses were used to assess numbers of neutrophils, goblet cells, and submucosal gland cells in NPs. Percentages of CD8+ T cells and CD4+CD25+Foxp3+ regulatory T cells (Tregs) were evaluated using flow cytometry. Mucin 5AC (MUC5AC), MUC5B, myeloperoxidase (MPO), interferon (IFN)-γ, and interleukin (IL)-1β and their mRNAs were also examined. After that, we cultured NP tissues in vitro and evaluated the abovementioned inflammatory parameters before and after the administration of budesonide.

RESULTS

Budesonide nasal spray did not improve clinical evaluations including VAS, SNOT-22, and EA scores. Numbers of neutrophils and goblet cells, the score of submucosal gland cells, percentages of CD8+ T cells and Tregs, MUC5AC, MUC5B, MPO, IFN-γ, and IL-1β and their mRNAs were not decreased in NPs after the budesonide treatment. Furthermore, the administration of budesonide into NP cultures also did not reduce their levels in comparison with those before the treatment.

CONCLUSION

These findings demonstrate that budesonide treatment may not alleviate the inflammatory condition in neutrophilic CRSwNP.

Increased thrombin-activatable fibrinolysis inhibitor levels in patients with chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease subdivided based on the presence or absence of nasal polyps (NPs). Histologic features of chronic rhinosinusitis with nasal polyps (CRSwNP) include inflammatory cell infiltration and excessive fibrin deposition in NPs. Thrombin-activatable fibrinolysis inhibitor (TAFI) is an enzyme that plays an antifibrinolytic role in the body. The significance of TAFI has been documented in patients with chronic inflammatory diseases, including chronic lung disease; however, it has not been evaluated in the pathogenesis of NPs.

OBJECTIVE

The objective of this study was to evaluate the potential role of TAFI in the pathogenesis of NPs.

METHODS

Nasal lavage fluid was collected from control subjects and patients with CRS. We measured levels of thrombin/anti-thrombin complex (TATc) and TAFI protein using an ELISA.

RESULTS

TATc levels in nasal lavage fluid were significantly increased in patients with CRSwNP and patients with chronic rhinosinusitis without nasal polyps (CRSsNP) compared with control subjects, and TAFI levels in nasal lavage fluid were also significantly increased in patients with CRSwNP compared with those in control subjects and patients with CRSsNP. There was a significant correlation between TATc and TAFI levels in nasal lavage fluid. Interestingly, patients with CRS and asthma showed increased TATc and TAFI levels in nasal lavage fluid compared with those in patients with CRS without asthma, especially patients with CRSwNP.

CONCLUSIONS

Increased TATc and TAFI levels in nasal passages of patients with CRSwNP might participate in fibrin deposition in NPs and might play a role in the pathogenesis of CRSwNP and asthma.

Allergic rhinitis is a risk factor of gastro-esophageal reflux disease regardless of the presence of asthma

Gastroesophageal reflux disease (GERD) can cause several upper airway symptoms and alter the physiology of nasopharyngeal mucosa, while upper airway diseases in turn might also exacerbate GERD symptoms. For a long time, asthma was considered a risk factor of GERD in the literature. Asthma and allergic rhinitis (AR) are usually identified as united airway disease according to similar epidemiology and pathophysiology; however, the association between AR and GERD is less elucidated. We aimed to evaluate whether AR would increase the development of GERD. Patients diagnosed as AR were identified from the National Health Insurance Research Database between January 1, 2000 and December 31, 2005 without prior history of gastroesophageal reflux disease. The outcome of interest was new-onset GERD. Cox regression models were applied to calculate the hazard ratio (HR) of GERD. We analyzed the data of 193,810 AR patients aged 18 years or older and being free of AR at baseline. The AR cohort (n = 96,905) had a significantly increased risk of GERD over a non-AR cohort (n = 96905) (adjusted HR (aHR) 1.94; 95% CI = 1.88–1.99, p < 0.001). AR may have stronger correlation with GERD than does asthma, although asthma might increase GERD risk by means of certain pathways shared with AR.

The use of biologics in children with allergic rhinitis and chronic rhinosinusitis: Current updates

The therapeutic goals of the treatment of allergic rhinitis (AR) and chronic rhinosinusitis (CRS) are symptom relief, avoiding complications, and improving quality of life. In the treatment of AR and CRS, several limitations of currently prescribed medicines have been identified. Antihistamine administration (both oral and topical) together with intranasal corticosteroids bring relief to the majority of patients, but their dependency on the medications and a necessity to maintain strict compliance with regular medication regimes pose a challenge. Immunotherapeutic agents are an option in some patients, but polysensitized patients, the risk of anaphylaxis, and the need for daily administration for years are limiting it from becoming the main therapy modality. Immunotherapy in any form requires commitment by the patient, which renders adherence and compliance issues particularly relevant. The procedure involved are generally time-consuming and entail an associated risk of severe adverse reactions. The use of biologics could overcome the limitations of other therapeutic modalities. They could be used as a monotherapy or combined with pre-existing medications. The benefits of targeted therapy include less adverse effects and optimal efficacy. The aim of the present review was to investigate the collective literature to date pertaining to the role of biologics in managing children with AR and CRS.

A call for cost-effectiveness analysis for biologic therapies in chronic rhinosinusitis with nasal polyps

OBJECTIVE

To identify the need for cost-effectiveness analysis of biologic therapies in the treatment of chronic rhinosinusitis (CRS).

DATA SOURCES

Clinical trials of monoclonal antibodies (omalizumab, benralizumab, mepolizumab and dupilumab) for nasal polyposis or chronic rhinosinusitis published on PubMed.

STUDY SELECTIONS

Clinical trials of biologic therapies in CRS and nasal polyposis.

RESULTS

No cost-effectiveness analyses of biologic therapies in CRS have been performed.

CONCLUSION

As more clinical trials of biologic therapies for CRS are conducted, there is a need for cost-effectiveness analysis. Future analyses should consider these therapies as part of medical therapeutic options compared with surgery. To increase generalizability, analyses should include samples from allergy and primary care clinics rather than only otolaryngology clinics.

[Immunology of chronic rhinosinusitis with nasal polyps as a basis for treatment with biologicals]

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous and multifactorial inflammation of the nasal and paranasal mucosa. Until now, no internationally standardized classification could be developed. In most cases, CRS is phenotypically classified according to chronic rhinosinusitis with (CRScNP) and without nasal polyps (CRSsNP). However, recent studies could show that there are numerous endotypes within these phenotypes based on different inflammatory mechanisms. This review describes the important immunological mechanisms of CRScNP and highlights modern treatment options with biologicals directly addressing particular immunological processes.

METHODS

Current knowledge on immunological and molecular processes of CRS, particularly CRScNP, was extracted from Medline, PubMed, national and international study- and guideline-registers, and the Cochrane library by a systematic review of the literature.

RESULTS

Based on current literature, various immunological mechanisms for CRS and CRScNP could be identified. Relevant studies for the treatment of eosinophilic conditions such as asthma or CRScNP are presented and, if available, results of these studies are discussed.

CONCLUSION

The growing insight into the underlying immunological mechanisms of CRScNP could pave the way for new personalized treatment options such as biologicals in the future.

Sinus Infections, Inflammation, and Asthma

There is an important link between the upper and lower respiratory tracts whereby inflammation in one environment can influence the other. In acute rhinosinusitis, pathogen exposures are the primary driver for inflammation in the nose, which can exacerbate asthma. In chronic rhinosinusitis, a disease clinically associated with asthma, the inflammation observed is likely from a combination of an impaired epithelial barrier, dysregulated immune response, and potentially infection (or colonization) by specific pathogens. This review explores the associations between rhinosinusitis and asthma, with particular emphasis placed on the role of infections and inflammation.

Role of blood inflammatory cells in chronic rhinosinusitis with nasal polyps

BACKGROUND/OBJECTIVE

The pathophysiological and prognostic role of blood inflammatory cells in chronic rhinosinusitis with nasal polyps (CRSwNP) emerging from recent studies was investigated.

MATERIAL AND METHODS

The main available evidence and largely-recent publications were critically analyzed.

RESULTS

Several authors reported a direct association between blood eosinophilia and CRSwNP recurrence rates. In some large series, a direct association between recurrent CRSwNP and blood basophil values emerged too. CRSwNP patients' blood eosinophil and basophil values were strongly related. It was also found that preoperative neutrophil-to-lymphocyte, eosinophil-to-lymphocyte, and basophil-to-lymphocyte ratios were significantly higher in patients who experienced a disease relapse than in those who did not. In histologically-confirmed eosinophilic-type CRSwNP treated with endoscopic sinus surgery, mean blood eosinophil values dropped significantly from before to after the surgical procedure.

CONCLUSIONS/SIGNIFICANCE

CRSwNP endotypes have different inflammatory profiles reflected in the relative proportions of different types of blood cells. The available data support the theory that blood eosinophil and basophil levels should be included in the routine preoperative work-up of CRSwNP patients in order to give patients accurate prognostic information, adopt rational follow-up protocols after surgery, and provide dedicated postoperative medical treatments.

Non-Eosinophilic Chronic Rhinosinusitis With Nasal Polyps: Eosinophil, Basophil, and Neutrophil Blood Counts Before and After Surgery

OBJECTIVES

Research selectively investigating non-eosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP) is lacking. The inflammatory patterns seen in non-eosinophilic CRSwNP are still poorly understood. The present study is the first to compare blood eosinophil, basophil, and neutrophil counts before/after surgery in patients with non-eosinophilic CRSwNP stratified by their clinical features.

METHODS

The study concerned 107 consecutive patients with histologically confirmed non-eosinophilic CRSwNP who underwent endoscopic sinus surgery (ESS).

RESULTS

Statistical analysis ruled out any significant change in mean blood eosinophil, basophil, and neutrophil counts after ESS. A significant positive correlation emerged between blood eosinophil and basophil counts in both pre- and post-ESS laboratory tests. In the subcohort of allergic patients, a significant negative correlation was found after ESS between eosinophil and neutrophil levels and between basophil and neutrophil levels.

CONCLUSIONS

In eosinophilic CRSwNP, ESS can clear polyps, remove inflammatory tissue, and reduce the inflammatory cytokines it generates, with a consequent reduction in blood eosinophil levels. The different results in non-eosinophilic CRSwNP support the conviction that the 2 types of CRSwNP are entities with distinct inflammatory response patterns.

Severe refractory asthma: current treatment options and ongoing research

Patients with severe asthma have a greater risk of asthma-related symptoms, morbidities, and exacerbations. Moreover, healthcare costs of patients with severe refractory asthma are at least 80% higher than those with stable asthma, mainly because of a higher use of healthcare resources and chronic side effects of oral corticosteroids (OCS). The advent of new promising biologicals provides a unique therapeutic option that could achieve asthma control without OCS. However, the increasing number of available molecules poses a new challenge: the identification and selection of the most appropriate treatment. Thanks to a better understanding of the basic mechanisms of the disease and the use of predictive biomarkers, especially regarding the Th2-high endotype, it is now easier than before to tailor therapy and guide clinicians toward the most suitable therapeutic choice, thus reducing the number of uncontrolled patients and therapeutic failures. In this review, we will discuss the different biological options available for the treatment of severe refractory asthma, their mechanism of action, and the overlapping aspects of their usage in clinical practice. The availability of new molecules, specific for different molecular targets, is a key topic, especially when considering that the same targets are sometimes part of the same phenotype. The aim of this review is to help clarify these doubts, which may facilitate the clinical decision-making process and the achievement of the best possible outcomes.

Chronic Rhinosinusitis-Could Phenotyping or Endotyping Aid Therapy?

OBJECTIVES

We reviewed the phenotyping and endotyping of chronic rhinosinusitis (CRS) and treatment options.

METHODS

We searched PubMed, Google, Google Scholar, and the Proquest Central Database of the Kırıkkale University Library.

RESULTS

Phenotypes are observable properties of an organism produced by the environment acting upon the genotype, that is, patients with a particular disorder are subgrouped according to common characteristics. Currently, CRS is usually phenotyped as being with (CRSwNP) or without (CRSsNP) nasal polyps. However, this is not immutable as some individuals progress from nonpolyp to polypoid CRS over time. Phenotypes of CRS are also based on inflammatory patterns, generally CRSwNP is eosinophilic, CRSsNP neutrophilic; but there is a spectrum, rather than a clear-cut division into 2 types. An endotype is a subtype of a condition defined by a distinct functional or pathobiological mechanism. Endotypes of CRS can be (1) nontype Th2, (2) moderate type Th2, and (3) severe type Th2 immune reactions, based on cytokines and mediators such as IL4, 5, 13. CRS endotyping can also include a (1) type 2 cytokine-based approach, (2) eosinophil-mediated approach, (3) immunoglobulin E-based approach, and (4) cysteinyl leukotriene-based approach. Subdivisions of CRSwNP can be made into nonsteroidal anti-inflammatory drug-exacerbated respiratory disease, allergic fungal sinusitis, and eosinophil pauci-granulomatous arteritis by testing. General treatment for all CRS is nasal douching. The place of surgery needs careful reconsideration. Endotype-directed therapies include glucocorticosteroids, antibiotics, aspirin, antifungals, anticytokines, and immunoglobulin replacement. The recognition of united airways and the co-occurrence of CRSwNPs and severe asthma should lead to common endotyping of both upper and lower airways in order to better direct therapy.

CONCLUSION

Endotyping can allow for the identification of groups of patients with CRS with a high likelihood of successful treatment, such as patients with a moderate type 2 immune reaction or those with acquired immune deficiency.

High frequency of macrophages expressing elevated level of CD80, PD-Ls and TLR1 in nasal polyps of CRS patients

Identification of the association between tissue biomarkers, their surrogates in blood and clinical features, could provide new diagnostic tools and facilitate adequate choices of therapeutic interventions for selected patients suffering from CRS. The aim of present study was the assessment of macrophages in the polyp tissue and monocytes in the peripheral blood in the course of CRSwNP, and their functional immunophenotype. We analyzed 31 patients with CRSwNP. Nasal mucosa tissue was obtained via functional endoscopic sinus surgery (FESS). The control group included 10 patients with deviated nasal septum (DNS). Fluorochrome stained cells were proceed to acquisition using FACS Canto flow cytometer, and the results were analyzed using the software FACS Diva. In our study, we observed a significantly higher level of CD80, CD274, CD273 and TLR1 in nasal polyps compared to blood samples from patients with CRSwNP. This finding may suggest the importance of the PD-1 pathway as a therapeutic target in CRS and an important role for TLR1 in nasal polyp formation and maintenance. Our results may provide some insight into potential future targets of recurrent nasal polyp treatment and contribute to a better understanding of the inflammatory process in Chronic Rhinosinusitis.

Pathophysiologic mechanisms of chronic rhinosinusitis and their roles in emerging disease endotypes

OBJECTIVE

Chronic rhinosinusitis (CRS) is a heterogeneous disorder with distinct pathophysiologic mechanisms. Based on transcription factor expression and cytokine production patterns in different innate lymphoid cell (ILC) types, in parallel with those of adaptive CD4⁺ T-helper (T_H) cells and CD8⁺ cytotoxic T (Tc) cells, new perspectives on endotypes of patients are emerging for the immune response deviation into type 1 (orchestrated by ILC1s and Tc1, and T_H1 cells), type 2 (characterized by ILC2s and Tc2 and T_H2 cells), and type 3 (mediated by ILC3s and Tc17 and T_H17 cells). In addition, cluster analysis has been applied to endotyping of CRS in recent years, which has provided additional novel insights into CRS pathogenesis. This review assessed pathologic mechanisms of CRS based on type 1, 2, and 3 immune responses and how they inform us to begin to understand CRS endotypes. This review also assessed recent cluster analysis studies of CRS endotypes. The impact of endotype on therapeutic management of CRS also is summarized.

DATA SOURCES

Review of published literature.

STUDY SELECTIONS

Relevant literature concerning CRS endotypes and possible underlying mechanisms was obtained from a PubMed search and summarized.

RESULTS AND CONCLUSION

CRS with and without nasal polyps are composed of distinct endotypes with distinct deviated immune responses, pathogenic mechanisms, and different responses to medical and surgical treatment. An endotype of CRS with prominent type 2 immune responses is the best-studied endotype and generally can benefit from treatment with steroids and specific type 2 disrupting biologics.

Nasal polyposis pathophysiology: Endotype and phenotype open issues

PURPOSE

Endotyping chronic rhinosinusitis with nasal polyps (CRSwNP) poses a challenge for rhinologists nowadays. Phenotyping CRSwNP proved inappropriate as an approach to their classification because of their common clinical features. Endotyping, being based on the pathogenic mechanism, provides a precise picture more appropriate for use in clinical practice. Patients' treatment and follow-up can thus be tailored to cope with the degree of aggressiveness of a specific CRSwNP endotype. The aim of this study was to analyze the available information about the main currently accepted endotypes of CRSwNP; furthermore, we reported and commented evidence regarding some clinical conditions associated with nasal polyposis which could be related with new endotypes.

MATERIALS AND METHODS

Pubmed and Scopus electronic database were searched. The main available studies about CRSwNP endotyping published predominantly in the last 5 years were critically analyzed.

RESULTS

The pathophysiological features of some asthma-related CRSwNP (allergic fungal rhinosinusitis, aspirin-exacerbated respiratory disease) are quite well understood, including them among known endotypes of CRSwNP. On the other hand, because of their known pathophysiological mechanisms, some well-known diseases associated with aggressive forms of CRSwNP, such as eosinophilic granulomatosis with polyangiitis, primary ciliary dyskinesia and cystic fibrosis, should be investigated as potentially related with CRSwNP endotypes.

CONCLUSIONS

CRSwNP comprises several inflammatory endotypes defined by different pathogenic mechanisms. These endotypes correlate with the disease's clinical manifestations and behavior. A thorough understanding of CRSwNP endotypes will enable targeted medical therapies and tailored follow-up protocols.

Blood Eosinophil and Basophil Values Before and After Surgery for Eosinophilic-type Sinonasal Polyps

Background Blood eosinophil and basophil levels have recently been considered for the purpose of endotyping chronic rhinosinusitis with nasal polyps (CRSwNP). Histologically, eosinophilic-type CRSwNPs have been associated with high recurrence rates after treatment. Objective The present study was the first to compare blood eosinophil and basophil counts in eosinophilic-type CRSwNP patients before and after endoscopic sinus surgery. Methods The study concerned 79 consecutive patients with histologically confirmed eosinophilic-type CRSwNP treated with endoscopic sinus surgery. Results A significant drop in mean blood eosinophil counts and percentages occurred from before to after endoscopic sinus surgery in the cohort as a whole. Mean blood eosinophil counts and percentages were also reduced after surgery in the subcohorts of CRSwNP patients with (i) asthma, (ii) aspirin-exacerbated respiratory disease (AERD), and (iii) no allergy. Although blood eosinophil and basophil counts correlated directly before and after surgery, a statistical reduction in blood basophil counts and percentages after surgery emerged only in the subcohort of nonallergic CRSwNP patients. Conclusion Endoscopic sinus surgery can clear polyps, remove inflammatory tissue, and reduce inflammatory cytokine levels. Consistently with the biological mechanism described, endoscopic sinus surgery could coincide with a reduction in blood eosinophils in eosinophilic-type CRSwNP.

Short-chain fatty acids induce tissue plasminogen activator in airway epithelial cells via GPR41&43

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous chronic inflammatory disease generally divided based on the presence or absence of nasal polyps (NPs). One of the features of NPs is excessive fibrin deposition, which is associated with down-regulation of tissue plasminogen activator (t-PA) in NPs. As t-PA is expressed in epithelial cells, and epithelium is readily accessible to topical therapies, identifying compounds that can mediate the induction of t-PA would be a potential new strategy for the treatment of NPs.

OBJECTIVE

The objective of this study was to determine whether short-chain fatty acids (SCFAs) can induce t-PA in airway epithelial cells via their known receptors GPR41 and GPR43.

METHODS

We performed immunohistochemistry (IHC) to determine whether receptors for SCFAs, known as G protein-coupled receptor 41/free fatty acid receptor 3 (GPR41/FFAR3) and GPR43/FFAR2, are expressed in nasal tissue. Primary normal human bronchial epithelial (NHBE) cells were stimulated with different concentrations of SCFAs to test induction of t-PA, which was analysed by expression of mRNA and protein. Mediation of responses by SCFA receptors was evaluated by specific receptor gene silencing with siRNA.

RESULTS

Immunohistochemistry study revealed that airway epithelial cells expressed GPR41 and GPR43. Acetic acid, propionic acid, butyric acid and valeric acid significantly induced t-PA expression from two- to tenfolds. The strongest inducer of t-PA from NHBE cells was propionic acid; cells stimulated with propionic acid released t-PA into the supernatant in its active form. Gene silencing of GPR41 and GPR43 revealed that induction of t-PA by SCFAs was dependent upon both GPR41 and GPR43.

CONCLUSIONS AND CLINICAL RELEVANCE

Short-chain fatty acids were shown to induce airway epithelial cell expression of t-PA via GPR41 and GPR43. Topical delivery of potent compounds that activate these receptors may have value by reducing fibrin deposition and shrinking nasal polyp growth.