Nasal interleukin 25 as a novel biomarker for patients with chronic rhinosinusitis with nasal polyps and airway hypersensitiveness: A pilot study

Non-Type 2 and Mixed Inflammation in Chronic Rhinosinusitis and Lower Airway Disease

OBJECTIVE

The aim was to discuss the role of non-type 2 inflammation in patients diagnosed with chronic rhinosinusitis (CRS) and comorbid lower airway disease.

DATA SOURCES

Medline, Embase, National Institute for Health and Care Excellence, TRIP Database, ProQuest, Clinicaltrials.gov, Cochrane Central Registry of Controlled Trials, Web of Science, government and health organizations, and graduate-level theses.

REVIEW METHODS

This scoping review followed PRISMA-ScR guidelines. Search strategy was peer-reviewed by medical librarians. Studies were included if they utilized airway sampling, non-type 2 cytokines, and patients with CRS and lower airway disease.

RESULTS

Twenty-seven from 7060 articles were included. In patients with CRS and comorbid asthma, aspirin-exacerbated respiratory disease (AERD), and chronic obstructive pulmonary disease (COPD)/bronchiectasis, 60% (n = 12), 33% (n = 2), and 100% (n = 1), respectively, demonstrated mixed or non-type 2 endotypes. Comorbid CRS and asthma produced type 1 (n = 1.5), type 2 (n = 8), type 3 (n = 1), mixed type 1/2 (n = 1), and mixed type 1/2/3 (n = 8.5) endotype shifts. AERD demonstrated type 2 (n = 4), mixed type 2/3 (n = 1), and mixed type 1/2/3 (n = 1) endotype shifts. CRS with COPD or bronchiectasis demonstrated a mixed 1/2 (n = 1) endotype shift.

CONCLUSION

Type 2 disease has been extensively reviewed due to advent biologics targeting type 2 inflammation, but outcomes may be suboptimal due to the presence of non-type 2 inflammation. A proportion of patients with CRS and comorbid lower airway disease demonstrated mixed and non-type 2 endotype shifts. This emphasizes that patients with unified airway disease may have forms of inflammation beyond classical type 2 disease which could inform biologic development. Laryngoscope, 134:1005-1013, 2024.

Systematic Review of Protein Biomarkers in Adult Patients With Chronic Rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous condition characterized by differing inflammatory endotypes. The identification of suitable biomarkers could enable personalized approaches to treatment selection.

OBJECTIVE

This study aimed to identify and summarize clinical studies of biomarkers in adults with CRS in order to inform future research into CRS endotypes.

METHODS

We conducted systematic searches of MEDLINE and Web of Science from inception to January 30, 2022 and included all clinical studies of adult CRS patients and healthy controls measuring biomarkers using enzyme-linked immunosorbent assays or Luminex immunoassays. Outcomes included the name and tissue type of identified biomarkers and expression patterns within CRS phenotypes. Study quality was assessed using the National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies. A narrative synthesis was performed.

RESULTS

We identified 78 relevant studies involving up to 9394 patients, predominantly with CRS with nasal polyposis. Studies identified 80 biomarkers from nasal tissue, 25 from nasal secretions, 14 from nasal lavage fluid, 24 from serum, and one from urine. The majority of biomarkers found to distinguish CRS phenotypes were identified in nasal tissue, especially in nasal polyps. Serum biomarkers were more commonly found to differentiate CRS from controls. The most frequently measured biomarker was IL-5, followed by IL-13 and IL-4. Serum IgE, IL-17, pentraxin-3 and nasal phospho-janus kinase 2, IL-5, IL-6, IL-17A, granulocyte-colony stimulating factor, and interferon gamma were identified as correlated with disease severity.

CONCLUSION

We have identified numerous potential biomarkers to differentiate a range of CRS phenotypes. Future studies should focus on the prognostic role of nasal tissue biomarkers or expand on the more limited studies of nasal secretions and nasal lavage fluid.We registered this study in PROSPERO (CRD42022302787).

The Diagnostic and Prognostic Role of Biomarkers in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) refers to an inflammatory disease of the sinonasal mucosa, with a significant economic burden and impact on quality of life. The diagnosis of CRS is conventionally made on careful history and physical examination, including nasoendoscopic assessment which requires technical expertise. There has been increasing interest in using biomarkers in the non-invasive diagnosis and prognostication of CRS, tailored to the disease inflammatory endotype. Potential biomarkers currently being studied can be isolated from peripheral blood, exhaled nasal gases or nasal secretions, as well as sinonasal tissue. In particular, various biomarkers have revolutionized the way in which CRS is managed, revealing new inflammatory pathways where novel therapeutic drugs are employed to curb the inflammatory process, which may be different from one patient to the next. Biomarkers that have been extensively studied in CRS, such as eosinophil count, IgE, and IL-5, have been associated with a T_H2 inflammatory endotype which correlates with an eosinophilic CRSwNP phenotype that predicts a poorer prognosis, tends to recur after conventional surgical treatment, but responds to glucocorticoid treatment. Newer biomarkers that demonstrate potential, such as nasal nitric oxide, can support a diagnosis of CRS with or without nasal polyps, especially when invasive tests such as nasoendoscopy are unavailable. Other biomarkers such as periostin can be used to monitor disease course after treatment of CRS. With a personalized treatment plan, the management of CRS can be individualized, optimizing treatment efficiency and reducing adverse outcomes. As such, this review aims to compile and summarize the existing literature regarding the utility of biomarkers in CRS in terms of diagnosis and prognostication, and also makes recommendations for further studies to fill current knowledge gaps.

TSLP, IL-33, and IL-25: Not just for allergy and helminth infection

The release of cytokines from epithelial and stromal cells is critical for the initiation and maintenance of tissue immunity. Three such cytokines, thymic stromal lymphopoietin, IL-33, and IL-25, are important regulators of type 2 immune responses triggered by parasitic worms and allergens. In particular, these cytokines activate group 2 innate lymphoid cells, TH2 cells, and myeloid cells, which drive hallmarks of type 2 immunity. However, emerging data indicate that these tissue-associated cytokines are not only involved in canonical type 2 responses but are also important in the context of viral infections, cancer, and even homeostasis. Here, we provide a brief review of the roles of thymic stromal lymphopoietin, IL-33, and IL-25 in diverse immune contexts, while highlighting their relative contributions in tissue-specific responses. We also emphasize a biologically motivated framework for thinking about the integration of multiple immune signals, including the 3 featured in this review.

TLR Signals in Epithelial Cells in the Nasal Cavity and Paranasal Sinuses

The respiratory tract is constantly at risk of invasion by microorganisms such as bacteria, viruses, and fungi. In particular, the mucosal epithelium of the nasal cavity and paranasal sinuses is at the very forefront of the battles between the host and the invading pathogens. Recent studies have revealed that the epithelium not only constitutes a physical barrier but also takes an essential role in the activation of the immune system. One of the mechanisms equipped in the epithelium to fight against microorganisms is the Toll-like receptor (TLR) response. TLRs recognize common structural components of microorganisms and activate the innate immune system, resulting in the production of a plethora of cytokines and chemokines in the response against microbes. As the epithelia-derived cytokines are deeply involved in the pathogenesis of inflammatory conditions in the nasal cavity and paranasal sinuses, such as chronic rhinosinusitis (CRS) and allergic rhinitis (AR), the molecules involved in the TLR response may be utilized as therapeutic targets for these diseases. There are several differences in the TLR response between nasal and bronchial epithelial cells, and knowledge of the TLR signals in the upper airway is sparse compared to that in the lower airway. In this review, we provide recent evidence on TLR signaling in the upper airway, focusing on the expression, regulation, and responsiveness of TLRs in human nasal epithelial cells (HNECs). We also discuss how TLRs in the epithelium are involved in the pathogenesis of, and possible therapeutic targeting, for CRS and AR.

Epithelial miR-206 targets CD39/extracellular ATP to upregulate airway IL-25 and TSLP in type 2-high asthma

The epithelial cell–derived cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) initiate type 2 inflammation in allergic diseases, including asthma. However, the signaling pathway regulating these cytokines expression remains elusive. Since microRNAs are pivotal regulators of gene expression, we profiled microRNA expression in bronchial epithelial brushings from type 2–low and type 2–high asthma patients. miR-206 was the most highly expressed epithelial microRNA in type 2–high asthma relative to type 2–low asthma but was downregulated in both subsets compared with healthy controls. CD39, an ectonucleotidase degrading ATP, was a target of miR-206 and upregulated in asthma. Allergen-induced acute extracellular ATP accumulation led to miR-206 downregulation and CD39 upregulation in human bronchial epithelial cells, forming a feedback loop to eliminate excessive ATP. Airway ATP levels were markedly elevated and strongly correlated with IL-25 and TSLP expression in asthma patients. Intriguingly, airway miR-206 antagonism increased Cd39 expression; reduced ATP accumulation; suppressed IL-25, IL-33, and Tslp expression and group 2 innate lymphoid cell expansion; and alleviated type 2 inflammation in a mouse model of allergic airway inflammation. In contrast, airway miR-206 overexpression had opposite effects. Overall, epithelial miR-206 upregulates airway IL-25 and TSLP expression by targeting the CD39–extracellular ATP axis, which represents a potentially novel therapeutic target in type 2–high asthma.

Evaluation of Sensitivity and Specificity of Interleukins 25 and 33 in Diagnosis of Pediatric Asthma

The roles of interleukin 25 (a member of the interleukin 17 family) and interleukin 33 (a member of the interleukin 1 family) in asthma and airway hyperresponsiveness are yet to be fully understood. The aim of this study was to investigate the roles of IL- 25 and IL- 33 in the diagnosis of pediatric asthma and their association with severity and treatment of the disease. This was a case-control study comprising 74 children with asthma as the patient group and 75 healthy children as the control group. The age of the participants ranged from 1 to 15 years. Levels of IL- 25 and IL- 33 in the serum were measured using ELISA kits. The highest positive predictive values (88.9%) occurred in IL- 25 with sensitivity and specificity of about 97.3% and 88.0% respectively, while the sensitivity and specificity of IL- 33 were about 51.4% and 66.0% respectively, with a positive predictive value of about (60.3%). The present study thus found that IL- 25 had higher diagnostic sensitivity and specificity values than IL- 33 in children with asthma. In addition, both interleukins were found to have a statistical significance regarding treatment of the disease in children.

Gene Expression Profiles of Circular RNAs and MicroRNAs in Chronic Rhinosinusitis With Nasal Polyps

Introduction: Chronic rhinosinusitis (CRS) is often classified primarily on the basis of the absence or presence of nasal polyps (NPs), that is, as CRS with nasal polyps (CRSwNP) or CRS without nasal polyps (CRSsNP). Additionally, according to the percentage of eosinophils, CRSwNP can be further divided into eosinophilic CRSwNP (ECRSwNP) and non-ECRSwNP. CRSwNP is a significant public health problem with a considerable socioeconomic burden. Previous research reported that the pathophysiology of CRSwNP is a complex, multifactorial disease. There have been many studies on its etiology, but its pathogenesis remains unclear. Dysregulated expression of microRNAs (miRNAs) has been shown in psoriasis, rheumatoid arthritis, pulmonary fibrosis, and allergic asthma. Circular RNAs (circRNAs) are also involved in inflammatory diseases such as rheumatoid arthritis, septic acute kidney injury, myocardial ischemia/reperfusion injury, and sepsis-induced liver damage. The function of miRNAs in various diseases, including CRSwNP, is a research hotspot. In contrast, there have been no studies on circRNAs in CRSwNP. Overall, little is known about the functions of circRNAs and miRNAs in CRSwNP. This study aimed to investigate the expression of circRNAs and miRNAs in a CRSwNP group and a control group to determine whether these molecules are related to the occurrence and development of CRSwNP. Methods: Nine nasal mucosa samples were collected, namely, three ECRSwNP samples, three non-ECRSwNP samples, and three control samples, for genomic microarray analysis of circRNA and microRNA expression. All of the tissue samples were from patients who were undergoing functional endoscopic sinus surgery in our department. Then we selected some differentially expressed miRNAs and circRNAs for qPCR verification. Meanwhile, GO enrichment analysis and KEGG pathway analysis were applied to predict the biological functions of aberrantly expressed circRNAs and miRNAs based on the GO and KEGG databases. Receiver operating characteristic (ROC) curve analysis and principal component analysis (PCA) were performed to confirm these molecules are involved in the occurrence and development of CRSwNP. Results: In total, 2,875 circRNAs showed significant differential expression in the CRSwNP group. Specifically, 1794 circRNAs were downregulated and 1,081 circRNAs were upregulated. In the CRSwNP group, the expression of 192 miRNAs was significantly downregulated, and none of the miRNAs were significantly upregulated. GO and KEGG analysis showed differential circRNAs and miRNAs were enriched in "amoebiasis," "salivary secretion," "pathways in cancer," and "endocytosis." Through qRT-PCR verification, the expression profiles of hsa-circ-0031593, hsa-circ-0031594, hsa-miR-132-3p, hsa-miR-145-5p, hsa-miR-146a-5p, and hsa-miR-27b-3p were shown to have statistical differences. In addition, ROC curve analysis showed that the molecules with the two highest AUCs were hsa-circ-0031593 with AUC 0.8353 and hsa-miR-145-5p with AUC 0.8690. Through PCA with the six ncRNAs, the first principal component explained variance ratio was 98.87%. The AUC of the six ncRNAs was 0.8657. Conclusion: In our study, the expression profiles of ECRSwNP and non-ECRSwNP had no statistical differences. The differentially expressed circRNAs and miRNAs between CRSwNP and control may play important roles in the pathogenesis of CRSwNP. Altered expression of hsa-circ-0031593 and hsa-miR-145-5p have the strongest evidence for involvement in the occurrence and development of CRSwNP because their AUCs are higher than the other molecules tested in this study.

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.

Manifesto on united airways diseases (UAD): an Interasma (global asthma association - GAA) document

OBJECTIVE

The large amount of evidence and the renewed interest in upper and lower airways involvement in infectious and inflammatory diseases has led Interasma (Global Asthma Association) to take a position on United Airways Diseases (UAD).

METHODS

Starting from an extensive literature review, Interasma executive committee discussed and approved this Manifesto developed by Interasma scientific network (INES) members.

RESULTS

The manifesto describes the evidence gathered to date and defines, states, advocates, and proposes issues on UAD (rhinitis, rhinosinusitis and nasal polyposis), and concomitant/comorbid lower airways disorders (asthma, chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis, obstructive sleep apnoea) with the aim of challenging assumptions, fostering commitment, and bringing about change. UAD refers to clinical pictures characterized by the coexistence of upper and lower airways involvement, driven by a common pathophysiological mechanism, leading to a greater burden on patient's health status and requiring an integrated diagnostic and therapeutic plan. The high prevalence of UAD must be taken into account. Upper and lower airways diseases influence disease control and patient's quality of life.

CONCLUSIONS

Patients with UAD need to have a timely and adequate diagnosis, treatment, and, when recommended, referral for management in a specialized center. Diagnostic testing including skin prick or serum specific IgE, lung function, fractional exhaled nitric oxide (FeNO), polysomnography, allergen-specific immunotherapies, biological therapies and home based continuous positive airway pressure (CPAP) whenever these are recommended, should be part of the management plan for UAD. Education of medical students, physicians, health professionals, patients and caregivers on the UAD is needed.

Prognostic and pharmacologic value of cystatin SN for chronic rhinosinusitis with nasal polyps

BACKGROUND

Integrated care pathways improve the management of patients with chronic rhinosinusitis with nasal polyps (CRSwNP). The application of integrated care pathways requires development of endotype-based biomarkers to stratify patients. The value of cytokines and markers induced by cytokines for the management of CRSwNP is largely unknown.

OBJECTIVES

Our aim was to determine the prognostic and pharmacologic value of type 2, non-type 2 cytokines, and markers associated with type 2 inflammation, including CCL26, periostin, and cystatin SN, in nasal secretions for CRSwNP.

METHODS

This retrospective study assigned 151 patients with CRSwNP to the discovery and validation phases. Concentrations of cytokines, CCL26, periostin, and cystatin SN in nasal secretions were determined by using Luminex and ELISA. Predictive significance was assessed with receiver-operating characteristic curves. Survival analysis was performed by using Kaplan-Meier curves and Cox regression models.

RESULTS

Cystatin SN was an independent predictor of the uncontrolled status of CRSwNP over a 2-year follow-up after adjustment for other risk factors (hazard ratio = 1.168 and 1.132 in the discovery and validation phases, respectively; both P < .001). Patients with high cystatin SN concentrations presented with a faster onset and higher rate of uncontrolled status than did those with low levels (P < .001). Enhanced medical treatment for patients with high cystatin SN levels postponed the uncontrolled status in the discovery (P = .016) and validation (P = .002) phases but did not completely abolish it by the end of the follow-up.

CONCLUSION

Cystatin SN levels in nasal secretions hold strong prognostic value and can facilitate medical instructions for managing CRSwNP.

Relationship between chemokines and T lymphocytes in the context of respiratory allergies (Review)

Allergic diseases have been classified in the last decades using various theories. The main classes of the newest classification in allergic respiratory diseases focus on the characterization of the endotype (which takes into account biomarkers related to determinant pathophysiological mechanisms) and of the phenotype (based on the description of the disease). Th2, Th1 and Th17 lymphocytes and the type of inflammatory response mediated by them represent the basis for Th2 and non-Th2 endotype classification. In addition, new lymphocytes were also used to characterize allergic diseases: Th9 lymphocytes, Th22 lymphocytes, T follicular helper cells (T_FH) lymphocytes and invariant natural killer T (iNKT) lymphocytes. In the last decade, a growing body of evidence focused on chemokines, chemoattractant cytokines, which seems to have an important contribution to the pathogenesis of this pathology. This review presents the interactions between chemokines and Th lymphocytes in the context of Th2/non-Th2 endotype classification of respiratory allergies.

Epithelial cell function and remodeling in nasal polyposis

OBJECTIVE

To review the latest discoveries on airway epithelial cell diversity and remodeling in type 2 inflammation, including nasal polyposis.

DATA SOURCES

Reviews and primary research manuscripts were identified from PubMed, Google, and Bioarchives, using the search words airway epithelium, nasal polyposis, or chronic rhinosinusitis with nasal polyposis AND basal cell, ciliated cell, secretory cell, goblet cell, neuroendocrine cell, pulmonary neuroendocrine cell, ionocyte, brush cell, solitary chemosensory cell, microvillus cell, or tuft cell.

STUDY SELECTIONS

Studies were selected based on novelty and likely relevance to airway epithelial innate immune functions or the pathobiology of type 2 inflammation.

RESULTS

Airway epithelial cells are more diverse than previously appreciated, with specialized subsets, including ionocytes, solitary chemosensory cells, and neuroendocrine cells that contribute to important innate immune functions. In chronic rhinosinusitis with nasal polyposis, the composition of the epithelium is significantly altered. Loss of ciliated cells and submucosal glands and an increase in basal airway epithelial progenitors leads to loss of innate immune functions and an expansion of proinflammatory potential. Type 2 cytokines play a major role in driving this process.

CONCLUSION

Airway epithelial remodeling in chronic rhinosinusitis is extensive, leading to loss of innate immune function and enhanced proinflammatory potential. The mechanisms driving airway remodeling and its sequelae deserve further attention before restitution of epithelial differentiation can be considered a reasonable therapeutic target.

Novel findings in immunopathophysiology of chronic rhinosinusitis and their role in a model of precision medicine

Our understanding of the pathophysiology of chronic rhinosinusitis (CRS) is continuously evolving. The traditional description of CRS in terms of two phenotypes based on the presence or absence of nasal polyps belies the underlying intricate immunopathophysiological processes responsible for this condition. CRS is being increasingly recognized as a disease spectrum encompassing a range of inflammatory states in the sinonasal cavity, with non-type 2 inflammatory disease on one end, type 2 inflammatory, eosinophil-heavy disease on the other and an overlap of both in different proportions in between. Abundance in research on the immune mechanisms of CRS has revealed various new endotypes that hold promise as biomarkers for the development of targeted therapies in severe, uncontrolled CRS. The introduction of precision medicine to manage this chronic, complex condition is a step forward in providing individualized care for all patients with CRS. In this review, the latest research on the pathophysiology of CRS with a focus on potential novel biomarkers and treatment options over the last 2 years are summarized and integrated into a suggested model of precision medicine in CRS.

Key role of the epithelium in chronic upper airways diseases

The respiratory epithelium of the upper airways is a first-line defence against inhaled irritants, pathogens and allergens. It ensures a physical barrier provided by apical junctions and mucociliary clearance to avoid excessive activation of the immune system. The epithelium also forms a chemical and immunological barrier, extensively equipped to protect the airways against external aggressions before the adaptive immune system is required. Under normal circumstances, the epithelium is capable of recovering rapidly after damage. This manuscript reviews these main properties of the upper airway epithelium as well as its reported impairments in chronic inflammatory diseases. The knowledge on normal epithelial functions and their dysregulation in upper airway diseases should help to design new epithelial-targeted treatments.

IL-25 Orchestrates Activation of Th Cells via Conventional Dendritic Cells in Tissue to Exacerbate Chronic House Dust Mite-Induced Asthma Pathology

House dust mite (HDM) extract is a common trigger of asthma in humans. Chronic exposure to HDM also induces asthma-like pathology in mice. Allergic responses to HDM and other allergens are linked to release of IL-25, IL-33, and TSLP by epithelial cells; these cytokines, especially IL-33, target innate lymphoid cells type 2 to produce type 2 cytokines. To what extent and by what mechanisms IL-25 contributes to chronic HDM-induced pathology is not well understood. In humans, elevated levels of IL-25 appear to be associated with cases of uncontrolled asthma and exacerbated attacks. In this article, we demonstrate that blockade of IL-25 signaling in either lung conventional dendritic cells or in T cells resulted in similar decreases in production of IL-13 and IL-9 by T cells, reduced mast cell accumulation and tissue remodeling, and improved lung function but had only modest effects on eosinophilia. Stimulation of conventional dendritic cells by IL-25 promoted proximal accumulation of Th cells, and stimulation of Th cells by IL-25 locally promoted IL-13 and IL-9 production. IL-25 made notable contributions to chronic HDM-induced allergic asthma pathology by facilitating clustering and cross-stimulation of different cell types in tissue. Therapeutic targeting of IL-25 in combination with other treatments may be beneficial.

Topical Corticosteroids Decrease IL-25 Expression by Immunohistochemistry

BACKGROUND

Interleukin-25 (IL-25) is an important contributing factor in the pathogenesis of allergic rhinitis. It leads to increasing peripheral and infiltrating eosinophilia as well as serum IgE, IgG, and Th2 cytokines (IL-4, IL-5, IL-13), which are responsible for the allergic symptoms. Intranasal steroids (INS) are effective in treating allergic rhinitis, but their effect on IL-25 release has not been studied. We aimed to study the link between IL-25 and the pathophysiology of allergic rhinitis as well as the effect of INS on its release.

METHODOLOGY

This was a cohort, prospective, nonrandomized study that included 60 patients, 35 allergic rhinitis patients and 25 controls. We studied the effect of INS on IL-25 release.

RESULTS

Of allergic rhinitis patients 68.6% had strong cytoplasmic stain of IL-25 in the epithelial layer, while 25.7% had intermediate stain. INS caused significantly reduced IL-25 stain as only 14.3% of patients had intermediate stain and 85.7% had weak stain. Moreover, a correlation was found between nasal smear eosinophilia and the degree of IL-25 staining in the epithelial layer.

CONCLUSION

Intranasal corticosteroids appear to be effective in the downregulation of IL-25, which may explain some of the utility of intranasal corticosteroid treatment in improving allergic rhinitis symptoms.

Recent advances in understanding chronic rhinosinusitis endotypes

Chronic rhinosinusitis (CRS) is a heterogeneous inflammatory disease with an as-yet-undefined etiology. The management of CRS has historically been phenotypically driven, and the presence or absence of nasal polyps has frequently guided diagnosis, prognosis, and treatment algorithms. Research over the last decade has begun to question the role of this distinction in disease management, and renewed attention has been placed on molecular and cellular endotyping and a more personalized approach to care. Current research exploring immunologic mechanisms, inflammatory endotypes, and molecular biomarkers has the potential to more effectively delineate distinct and clinically relevant subgroups of CRS. The focus of this review will be to discuss and summarize the endotypic characterization of CRS and the potential diagnostic and therapeutic implications of this approach to disease management.

Biomarkers in Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis is a complex disease that exists along the inflammatory spectrum between types 1 and 2 inflammation. The classic phenotypic differentiation of chronic rhinosinusitis based on the presence or absence of inflammatory polyps remains one of the best differentiators of response to therapy. Development of biologics for the treatment of atopic disease and asthma and topical therapies for sinusitis have placed renewed emphasis on understanding the pathophysiology of polyp disease. Identification of key markers of polyposis will allow for better stratification of inflammatory polyp disease endotypes to objectively identify medical therapies and track response to treatment.

The concepts of asthma endotypes and phenotypes to guide current and novel treatment strategies

INTRODUCTION

Asthma, a common, non-communicable chronic disease affects over 300 million individuals worldwide. The Western world lifestyle is claimed to be responsible for this high and increasing prevalence. Asthma has been defined as a syndrome with various phenotypes and endotypes, allergic asthma and type 2 asthma being the most frequent. A great increase in prevalence of allergic diseases has necessitated intensive investigations both for understanding the underlying mechanisms and for the development of novel therapy options with long-term efficacy and limited side-effects. Allergic patients demonstrate unique presentations with variable visible characteristics and disease outcomes depending on different molecular mechanisms, related to influence of genes and epigenetic control by micro- and macro-environment. Areas covered: This article reviews the definition of asthma phenotypes and possible endotypes, advances in allergy-immunology field and contemporary personalized therapy options for asthma. Expert commentary: Better understanding of the complex immune network of allergic inflammation and key players of immunity is continuously being provided for clarification of asthma sub-types. Successful therapy of asthma requires better definition of underlying pathogenesis, which sequentially could end up with 'custom-tailored' individualized, evidence-based and more precise therapy options; a new era termed as 'precision medicine'. Endotype, phenotype, theratype and biomarker terms arise as major keywords in precision/personalized medicine.

Solitary chemosensory cells producing interleukin-25 and group-2 innate lymphoid cells are enriched in chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is commonly characterized by type-2 inflammation. It is established that group-2 innate lymphoid cells (ILC2s) are a subset of immune cells important in orchestrating mucosal type-2 response. IL-25 is an epithelial-derived cytokine that is a critical activator of ILC2s. Recent evidence demonstrates that specialized taster epithelial cells, such as solitary chemosensory cells (SCCs), may be producers of IL-25. To elucidate the relationship between SCCs and ILC2s in CRSwNP, we sought to quantify ILC2s and SCCs to determine if these cell types are enriched in nasal polyps compared to healthy sinonasal mucosa.

METHODS

We quantified SCCs and ILC2s using multicolor flow cytometry in nasal polyps and non-inflamed turbinate mucosa from seven patients and investigated the role of IL-13 and dexamethasone on SCC frequency using tissue explants of nasal polyps and turbinate mucosa.

RESULTS

SCCs were found to be the primary source of IL-25. Nasal polyps demonstrated higher populations of SCCs (33.0% vs 5.6%, p < 0.001) and ILC2s (2.40% vs 0.19%, p = 0.008) compared to patient-matched nonpolypoid turbinates. In cultured polyp explants, exogenous IL-13 increased the proportion of epithelial SCCs (40.2% IL-13 condition vs 28.9% untreated, p = 0.012), and this effect was reversed by addition of dexamethasone (40.2% vs 8.9%, p < 0.0005).

CONCLUSION

These data support SCC and ILC2 expansion as well as increased IL-25 production in nasal polyps and may represent early events in the pathogenesis of CRSwNP. IL-13 stimulates proliferation of SCC in a feed-forward loop, a process that is steroid-sensitive.