Pathogenesis of aspirin-exacerbated respiratory disease and reactions

Severe Type 2 Inflammation Leads to High Platelet-Activating-Factor-Associated Pathology in Chronic Rhinosinusitis with Nasal Polyps-A Hierarchical Cluster Analysis Using Bulk RNA Barcoding and Sequencing

Platelet-activating factor (PAF) is a phospholipid-derived inflammatory mediator that triggers various inflammatory conditions, including eosinophil activation and recruitment. This study aimed to evaluate the expressions of PAF-metabolism-associated genes, namely genes coding the enzymes involved in PAF synthesis (LPCAT1, LPCAT2, LPCAT3, and LPCAT4), PAF degradation (PAFAH1B2, PAFAH1B3, and PAFAH2), and the gene for the PAF receptor (PTAFR) in subtypes of CRSwNP classified by clinical- or hierarchal-analysis-based classifications. Transcriptomic analysis using bulk RNA barcoding and sequencing (BRB-seq) was performed with CRSwNP, including eosinophilic CRS (ECRS) (n = 9), nonECRS (n = 8), ECRS with aspirin-exacerbated respiratory disease (Asp) (n = 3), and controls with a normal uncinate process mucosa (n = 6). PTAFR was only upregulated in ECRS and nonECRS. In the hierarchical cluster analysis with clusters 1 and 2 reflecting patients with low-to-moderate and high levels of type 2 inflammation, respectively, cluster 1 exhibited a significant downregulation of LPCAT2 and an upregulation of PTAFR expression, while cluster 2 showed an upregulation of LPCAT1, PAFAH1B2, and PTAFR and downregulation of PAFAH2 expression. Understanding this strong PAF-associated pathophysiology in the severe type 2 inflammation group could provide valuable insights into the treatment and management of CRSwNP.

Genomics of Treatable Traits in Asthma

The astounding number of genetic variants revealed in the 15 years of genome-wide association studies of asthma has not kept pace with the goals of translational genomics. Moving asthma diagnosis from a nonspecific umbrella term to specific phenotypes/endotypes and related traits may provide insights into features that may be prevented or alleviated by therapeutical intervention. This review provides an overview of the different asthma endotypes and phenotypes and the genomic findings from asthma studies using patient stratification strategies and asthma-related traits. Asthma genomic research for treatable traits has uncovered novel and previously reported asthma loci, primarily through studies in Europeans. Novel genomic findings for asthma phenotypes and related traits may arise from multi-trait and specific phenotyping strategies in diverse populations.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Inheritance of NSAID-Exacerbated Respiratory Disease

Nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (N-ERD) has been considered an acquired condition. Positive first-degree family history has been reported in 1% of cases. The geographic and genetic isolation of the Finnish population offers exceptional opportunities for inheritance studies. In this questionnaire study, we explored the familial aggregation of N-ERD in 66 Finnish families of patients with N-ERD. The majority of patients (67%) had a positive family history of NSAID intolerance, asthma, nasal polyposis, or N-ERD. Furthermore, 55% had a positive first-degree family history of asthma, 21% nasal polyposis, 20% NSAID intolerance, and 11% N-ERD. The prevalence of asthma, nasal polyposis, NSAID intolerance, and N-ERD among first-degree relatives was 13%, 5%, 4%, and 2%, respectively. We present the pedigrees of the 44 affected families. According to our findings, Finnish patients with N-ERD seem to have a genetic susceptibility to it.

The role of oxylipins in NSAID-exacerbated respiratory disease (N-ERD)

Nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (N-ERD) is characterized by nasal polyp formation, adult-onset asthma, and hypersensitivity to all cyclooxygenase-1 (COX-1) inhibitors. Oxygenated lipids are collectively known as oxylipins and are polyunsaturated fatty acids (PUFA) oxidation products. The most extensively researched oxylipins being the eicosanoids formed from arachidonic acid (AA). There are four major classes of eicosanoids including leukotrienes, prostaglandins, thromboxanes, and lipoxins. In N-ERD, the underlying inflammatory process of the upper and lower respiratory systems begins and occurs independently of NSAID consumption and is due to the overproduction of cysteinyl leukotrienes. Leukotriene mediators all induce edema, bronchoconstriction, and airway mucous secretion. Thromboxane A2 is a potent bronchoconstrictor and induces endothelial adhesion molecule expression. Elevated Prostaglandin D2 metabolites lead to vasoconstriction, additionally impaired up-regulation of prostaglandin E2 leads to symptoms seen in N-ERD as it is essential for maintaining homeostasis of inflammatory responses in the airway and has bronchoprotective and anti-inflammatory effects. A characteristic feature of N-ERD is diminished lipoxin levels, this decreased capacity to form endogenous mediators with anti-inflammatory properties could facilitate local inflammatory response and expose bronchial smooth muscle to relatively unopposed actions of broncho-constricting substances. Treatment options, such as leukotriene modifying agents, aspirin desensitization, biologic agents and ESS, appear to influence eicosanoid pathways, however more studies need to be done to further understand the role of oxylipins. Besides AA-derived eicosanoids, other oxylipins may also pay a role but have not been sufficiently studied. Identifying pathogenic N-ERD mechanism is likely to define more effective treatment targets.

Retinoic acid promotes fibrinolysis and may regulate polyp formation

BACKGROUND

Patients with aspirin-exacerbated respiratory disease (AERD) regularly exhibit severe nasal polyposis. Studies suggest that chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by excessive fibrin deposition associated with a profound decrease in epithelial tissue plasminogen activator (tPA). Retinoids, including vitamin A and its active metabolite retinoic acid (RA), are necessary for maintaining epithelial function and well-known inducers of tPA in endothelial cells.

OBJECTIVES

This study sought to determine whether endogenous retinoids are involved in NP pathophysiology and disease severity in patients with CRSwNP and AERD.

METHODS

NP tissue was collected from patients with AERD or CRSwNP, and concentrations of retinoids and fibrinolysis markers were measured using ELISA. Normal human bronchial epithelial cells were stimulated alone or in combination with RA and IL-13 for 24 hours.

RESULTS

This study observed lower retinoid levels in nasal polyps of patients with AERD than those with CRSwNP or healthy controls (P < .01). Levels of the fibrin-breakdown product d-dimer were the lowest in AERD polyps (P < .01), which is consistent with lower tPA expression (P < .01). In vitro, all-trans RA upregulated tPA levels in normal human bronchial epithelial cells by 15-fold and reversed the IL-13-induced attenuation of tPA expression in cultured cells (P < .01).

CONCLUSIONS

RA, a potent inducer of epithelial tPA in vitro, is reduced in tissue from patients with AERD, a finding that may potentially contribute to decreased levels of tPA and fibrinolysis in AERD. RA can induce tPA in epithelial cells and can reverse IL-13-induced tPA suppression in vitro, suggesting the potential utility of RA in treating patients with CRSwNP and/or AERD.

The Role of Omalizumab in NSAID-Exacerbated Respiratory Disease: A Narrative Review

Nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD) is a condition characterized by the triad of chronic rhinosinusitis with nasal polyps, bronchial asthma, and hypersensitivity to nonsteroidal anti-inflammatory drugs. This article explores the current knowledge on the various pathological mechanism(s) of N-ERD-such as arachidonic acid metabolism, cysteinyl leukotrienes, prostaglandins, platelets, IgE, mast cells, eosinophils, basophils, and innate immune system-and the role of omalizumab in its management. The authors dive deep into the role of IgE in N-ERD and its potential as a therapeutic target. IgE plays a significant role in mediating allergic reactions, is intricately linked with mast cells, interacts with multiple immunopathological pathways involved in N-ERD, and tends to be elevated in patients with N-ERD. Multiple real-world studies, observational studies, and case series, as well as 2 phase III trials, have demonstrated the effectiveness of omalizumab in the management of N-ERD. For a disease with such a well-documented history, the pathophysiology of N-ERD and the most effective ways to manage it remain a mystery. With this background, the authors ask-is IgE a missing piece of the N-ERD puzzle, thus explaining the efficacy of omalizumab in the treatment of the disease?

Endoscopic outcomes in patients with AERD treated with topical antibiotics and intranasal corticosteroids

Background

Identifying effective therapy for recalcitrant chronic rhinosinusitis with nasal polyposis (CRSwNP) is a major challenge; and subtypes such as aspirin-exacerbated respiratory disease (AERD) are even more difficult to treat. Evidence on topical antibiotics use in (CRSwNP) is lacking. Current consensus guidelines recommend against its routine use, but recent reviews show some benefit when managing recalcitrant disease after endoscopic sinus surgery (ESS).

Objective

Evaluate the effect of culture-directed topical antibiotics on sinonasal outcomes in AERD patients with a positive perioperative sinonasal bacterial culture who have undergone ESS.

Methods

A retrospective cohort study of AERD patients with positive sinonasal culture, who underwent ESS from 2016 to 2021 was performed. Forty-four patients were identified and stratified based on their postoperative medical treatment. Twenty-six underwent postoperative intranasal corticosteroids (INCS) alone, while eighteen underwent INCS plus a 4-weeks treatment with topical antibiotics. SNOT-22 and Lund-Kennedy score (LKS) were assessed preoperatively and at 4-weeks and 4-6 months after ESS.

Results

A statistically significant improvement in the 4-weeks and 4-6 months postoperative SNOT-22 and LKS were noted within both groups (p&lt;0.05). However, only a statistically significant difference was found in the 4-weeks postoperative LKS when comparing between treatment groups (p=0.01). Our linear regression model demonstrated a relationship between the use of combined therapy with INCS and topical antibiotics and the LKS 4-weeks post ESS (p=0.015).

Conclusion

In AERD patients with a confirmed sinus infection, the combination of culture-directed topical antibiotics and intranasal corticosteroid irrigations in the postoperative period can provide a short-term improvement in endoscopic scores.

Steroid affected cytokines in aspirin exacerbated respiratory disease

BACKGROUND

Patients with aspirin exacerbated respiratory disease (AERD) are among the most challenging rhinologic patients to treat. AERD has a complex inflammatory milieu of lipid mediators and cytokines. In this study we evaluated cytokine differences in the complex AERD environment at the mucus, epithelial and tissue levels.

METHODS

Samples were acquired at the time of sinus surgery from twenty-one patients (7 steroid-treated, 14 untreated) with aspirin challenge-confirmed AERD. Three methods (sponge adsorption, epithelial brushing, tissue biopsy) were used to acquire samples from the respective sinus sampling sites (mucus, polyp epithelium, and full thickness polyp) of each patient. We measured and compared 16 cytokine concentrations in AERD patients with or without prednisone treatment using the Luminex platform.

RESULTS

In most sampling sites, IL-5, IL-6, IL-10, IL-13, IL-33, CCL20, and TNF-α were detected at higher concentrations than IFN-γ, IL-1β, IL-17A, IL-4, IL-22, IL-17E/IL25 and GM-CSF. Each sampling site had a different pattern of cytokine levels and except for IL-5 and IL-25 there was no correlation among sampling methods for each cytokine tested. The most notable and significant decreases in cytokines from those treated with prednisone were observed in the epithelium for IL-5, IL-10, IL-33, and IFN-γ.

CONCLUSIONS

In the epithelial samples, type 2 associated cytokines IL-5 and IL-33, the anti-inflammatory cytokine IL-10, and IFN-γ were lower in AERD patients treated with prednisone. This work serves as a basis to assess therapeutic-induced mucosal cytokine responses in AERD and indicates that the site of cytokine measurement is an important consideration when assessing results. This article is protected by copyright. All rights reserved.

Obliterative sinusitis: An underreported clinical entity

Obliterative paranasal sinusitis is a rare sequela and end stage of chronic rhinosinusitis, which is often overlooked on imaging. It is an exuberant form of neo-osteogenesis characterized by complete or partial obliteration of the sinus cavity by new bone formation. This article presents a series of cases of obliterative sinusitis involving the sphenoid and maxillary sinuses. It is important to comment on the presence of obliterative sinusitis in the radiology report and not confuse it for native bone, fibro-osseous lesion, or arrested pneumatization, as this may have clinical implications for patients being considered for surgery. Given its potential implications for severity of sinusitis as well as prognostic significance for outcomes following endoscopic sinus surgery, awareness and timely identification of this entity is important to guide referring clinicians.

Asthma Phenotypes as a Guide for Current and Future Biologic Therapies

Asthma has been increasingly recognized as being a heterogeneous disease with multiple distinct mechanisms and pathophysiologies. Evidence continues to build regarding the existence of different cell types, environmental exposures, pathogens, and other factors that produce a similar set of symptoms known collectively as asthma. This has led to a movement from a "one size fits all" symptom-based methodology to a more patient-centered, individualized approach to asthma treatment targeting the underlying disease process. A significant contributor to this shift to more personalized asthma therapy has been the increasing availability of numerous biologic therapies in recent years, providing the opportunity for more targeted treatments. When targeted biologics began to be developed for treatment of asthma, the hope was that distinct biomarkers would become available, allowing the clinician to determine which biologic therapy was best suited for which patients. Presence of certain biomarkers, like eosinophilia or antigen-specific IgE, is important features of specific asthma phenotypes. Currently available biomarkers can help with decision making about biologics, but are generally too broad and non-specific to clearly identify an asthma phenotype or the single biologic best suited to an asthmatic. Identification of further biomarkers is the subject of intense research. Yet, identifying a patient's asthma phenotype can help in predicting disease course, response to treatment, and biologic therapies to consider. In this review, major asthma phenotypes are reviewed, and the evidence for the utility of various biologics, both those currently on the market and those in the development process, in each of these phenotypes is explored.

The Emerging Role of COX-2, 15-LOX and PPARγ in Metabolic Diseases and Cancer: An Introduction to Novel Multi-target Directed Ligands (MTDLs)

Emerging evidence supports an intertwining framework for the involvement of different inflammatory pathways in a common pathological background for a number of disorders. Of importance are pathways involving arachidonic acid metabolism by cyclooxygenase-2 (COX-2) and 15-lipoxygenase (15-LOX). Both enzyme activities and their products are implicated in a range of pathophysiological processes encompassing metabolic impairment leading to adipose inflammation and the subsequent vascular and neurological disorders, in addition to various pro- and antitumorigenic effects. A further layer of complexity is encountered by the disparate, and often reciprocal, modulatory effect COX-2 and 15-LOX activities and metabolites exert on each other or on other cellular targets, the most prominent of which is peroxisome proliferator-activated receptor gamma (PPARγ). Thus, effective therapeutic intervention with such multifaceted disorders requires the simultaneous modulation of more than one target. Here, we describe the role of COX-2, 15-LOX, and PPARγ in cancer and complications of metabolic disorders, highlight the value of designing multi-target directed ligands (MTDLs) modifying their activity, and summarizing the available literature regarding the rationale and feasibility of design and synthesis of these ligands together with their known biological effects. We speculate on the potential impact of MTDLs in these disorders as well as emphasize the need for structured future effort to translate these early results facilitating the adoption of these, and similar, molecules in clinical research.

Untapped Potential: Therapeutically Targeting Eicosanoids and Endocannabinoids in the Lung

Inflammation of the airway involves the recruitment of highly active immune cells to combat and clear microbes and toxic factors; however, this inflammatory response can result in unintended damage to lung tissue. Tissue damage resulting from inflammation is often mitigated by resolving factors that limit the scope and duration of the inflammatory response. Both inflammatory and resolving processes require the actions of a vast array of lipid mediators that can be rapidly synthesized through a variety of airway resident and infiltrating immune cells. Eicosanoids and endocannabinoids represent two major classes of lipid mediators that share synthetic enzymes and have diverse and overlapping functions. This review seeks to provide a summary of the major bioactive eicosanoids and endocannabinoids, challenges facing researchers that study them, and their roles in modulating inflammation and resolution. With a special emphasis on cystic fibrosis, a variety of therapeutics are discussed that have been explored for their potential anti-inflammatory or proresolving impact toward alleviating excessive airway inflammation and improving lung function.

The dental management of the asthmatic patients

Asthma is the most common chronic respiratory condition characterized by airway inflammation and obstruction. Our increased knowledge and understanding of the etiology and pathogenesis of this condition has widely assisted us in delivering effective therapies. Physicians strive to provide the best treatment modality to achieve symptom-control and minimize the adverse effects of medication use. Nonetheless, patients continue to endure oral complications from the use of asthma medications. As dentists, it is prudent to address these oral complications and promote the oral health of these patients by way of early preventive and therapeutic dental intervention. This must be accomplished by adhering to certain precautionary measures for the sake of avoiding intraoperative problems while optimizing oral care. In this article, we discuss the diagnosis, oral findings, dental care, and emergency management of the asthmatic patients.

NSAID-Exacerbated Respiratory Disease (NERD): From Pathogenesis to Improved Care

Nonsteroidal antiinflammatory drug (NSAID)-exacerbated respiratory disease (NERD) is characterized by moderate-to-severe asthma and a higher prevalence of chronic rhinosinusitis/nasal polyps, but is a highly heterogeneous disorder with various clinical manifestations. Two major pathogenic mechanisms are: (1) overproduction of cysteinyl leukotrienes with dysregulation of arachidonic acid metabolism and (2) increased type 2 eosinophilic inflammation affected by genetic mechanisms. Aspirin challenge is the gold standard to diagnose NERD, whereas reliable in vitro biomarkers have yet not been identified. Therapeutic approaches have been done on the basis of disease severity with the avoidance of culprit and cross-reacting NSAIDs, and when indicated, aspirin desensitization is an effective treatment option. Biologic approaches targeting Type 2 cytokines are emerging as potential therapeutic options. Here, we summarize the up-to-date evidence of pathophysiologic mechanisms and diagnosis/management approaches to the patients with NERD with its phenotypic classification.

A Comparison of Sphenoid Sinus Osteoneogenesis in Aspirin-Exacerbated Respiratory Disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is characterized by excessive leukotriene production, diffuse polyp burden and osteitic bone changes. These bony changes have not been previously characterized.

OBJECTIVE

The aim of this radiographic study is to characterize the bony changes noted on computed tomography (CT) scans of the sphenoid sinus in patients with AERD compared to other diseased sinonasal inflammatory states and non-diseased controls.

METHODS

A retrospective review of 43 patients with clinically confirmed AERD were included and compared to 22 non-diseased, 9 allergic fungal sinusitis, and 43 chronic rhinosinusitis controls (23 without polyps and 18 with polyps). Comparative measurements were performed using fine-cut CT scans. Sites of comparison were the intersinus septum, the left and right lateral sphenoid wall, the roof, and left and right floor of the sphenoid sinus. Standardized measurements were averaged by two separate rhinologists.

RESULTS

Patients with AERD had an average statistically significant increase in bone thickness compared to healthy and diseased controls in nearly every site with the most pronounced changes in the intersinus septum (p < 0.05).

CONCLUSION

Patients with AERD have significantly increased thickness of the sphenoid bone compared to control groups with the most pronounced difference in the intersinus septum. These findings may help clinicians increase suspicion for a diagnosis of AERD who clinically have diffuse nasal polyposis.

Associations between TMEM196 polymorphisms and NSAID-exacerbated respiratory disease in asthma

BACKGROUND

We previously found differences in the minor allele frequency (MAF) of single-nucleotide polymorphisms (SNPs) in transmembrane protein 196 (TMEM196) between 995 patients with aspirin-tolerant asthma (ATA) and 141 asthmatic patients with NSAID-exacerbated respiratory disease (NERD). In this study, we statistically analyzed the distributions of the genotypes and haplotypes of these SNPs to determine the exact association between TMEM196 genetic variants and the risk for NERD.

MATERIALS AND METHODS

Lewontin's D' and r values were used to measure linkage disequilibrium between the biallelic loci having MAFs more than 0.05, and haplotypes were inferred using the PHASE algorithm (version 2.0). The genotype distribution was analyzed by logistic regression models using age of onset, smoking status (nonsmoker=0, ex-smoker=1, smoker=2), and BMI as covariates. Regression analysis of the association between SNPs and the risk of NERD was analyzed using SPSS version 12.0 and PLINK version 1.9.

RESULTS

The MAF of rs9886152 C>T was significantly lower in NERD than in ATA [24.8 vs. 34.0%, odds ratio=0.64 (0.48-0.85), P=2.07×10, Pcorr=0.048]. The rate of the rs9886152 C>T minor allele was significantly lower in NERD than in ATA [44.0 vs. 56.4% in the codominant model, P=0.002, Pcorr=0.049, odds ratio=0.64 (0.48-0.85)]. An additional three SNPs (rs9639334 A>G, rs9638765 A>G, and rs2097811 G>A) showed similar associations with the risk of NERD. NERD patients had lower frequencies of the rs9639334 A>G minor allele (51.1 vs. 64.4%, P=0.002, Pcorr=0.043), rs9638765 A>G (49.7 vs. 64.2%, P=0.001, Pcorr=0.017), and rs2097811 G>A (51.1 vs. 64.5%, P=0.002, Pcorr=0.04) compared with ATA patients. Patients homozygous for the minor alleles of the four SNPs showed significantly less of an aspirin-induced decrease in forced expiratory volume in one second compared with those homozygous for the common alleles (P=0.003-0.012).

CONCLUSION

The minor alleles of the four SNPs in TMEM196 may exert a protective effect against the development of NERD and may be useful genetic markers to predict the risk of NERD.

The time course of nasal cytokine secretion in patients with aspirin-exacerbated respiratory disease (AERD) undergoing aspirin desensitization: preliminary data

PURPOSE

Aspirin-exacerbated respiratory disease (AERD) is a severe form of chronic rhinosinusitis with nasal polyps (CRSwNP) accompanied by asthma and an aspirin intolerance. The underlying pathomechanism of AERD still remains unclear, recent data suggest a complex inflammatory imbalance. In the present study, we investigated the cytokine patterns in AERD, CRSwNP and healthy control patients. Furthermore, we describe the change in cytokine level in the course of aspirin desensitization (AD) with continuous intake of aspirin.

METHODS

The study included a total of 104 participants, 48 healthy controls, 45 patients with nasal polyps and 11 patients with AERD undergoing AD. Nasal secretions were analyzed for IL-1β, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17, THF-α, IFN-γ, eotaxin and ECP using Bio-Plex Human Cytokine Assay and Uni-CAP FEIA. Baseline measurements of cytokine levels were performed in all 104 patients; in patients with AERD, follow-up was performed 1-6 and 6-24 months after the initiation of AD.

RESULTS

Our preliminary results show a T_H2 dominated, eosinophilic milieu in AERD patients, which decreased in the first weeks of AD. However, after 6 months of AD, proinflammatory cytokines show a tendency to increase again. Also, T_H1 as well as T_reg associated cytokine seem to increase over time.

CONCLUSIONS

For the first time, the present work shows the cytokine pattern in nasal secretions of AERD patients before and during AD. Further investigation of the complex interaction of inflammatory cytokines during AD might reveal important insights into the disease entity of AERD and open up new horizons for a targeted therapy.

The Role of Leukotrienes as Potential Therapeutic Targets in Allergic Disorders

Leukotrienes (LTs) are lipid mediators that play pivotal roles in acute and chronic inflammation and allergic diseases. They exert their biological effects by binding to specific G-protein-coupled receptors. Each LT receptor subtype exhibits unique functions and expression patterns. LTs play roles in various allergic diseases, including asthma (neutrophilic asthma and aspirin-sensitive asthma), allergic rhinitis, atopic dermatitis, allergic conjunctivitis, and anaphylaxis. This review summarizes the biology of LTs and their receptors, recent developments in the area of anti-LT strategies (in settings such as ongoing clinical studies), and prospects for future therapeutic applications.

Aspirin Exacerbated Respiratory Disease: Epidemiology, Pathophysiology, and Management

The correlation between aspirin sensitivity, asthma, and nasal polyposis was recognized in the early 20th century. Today, this classic triad of symptoms, eponymously named Samter's Triad, is known as aspirin exacerbated respiratory disease (AERD). Aspirin exacerbated respiratory disease affects approximately 0.3⁻0.9% of the general population in the USA and approximately 7% of asthmatic patients. The management of AERD is challenging as no single modality has proven to have high rates of symptom control. Consequently, disease management typically involves a multimodality approach across both medical and surgical disciplines. This review describes the epidemiology of AERD and the current state-of-the-art as it relates to the underlying pathophysiologic mechanisms of this disease process. A significant proportion of the review is focused on the appropriate diagnostic workup for AERD patients including the utility of aspirin provocation testing. The spectrum of medical treatments, including aspirin desensitization and recently introduced immunotherapies, are discussed in detail. Furthermore, surgical approaches to disease control, including advanced endoscopic techniques, are reviewed and treatment outcomes presented.

Differential Diagnosis of Asthma

Asthma is one of the most common chronic syndromes worldwide (Moorman et al., Vital Health Stat 3(35), 2012). It is not a diagnosis but a clinical syndrome based on a constellation of signs and symptoms (Li et al., Ann Allergy Asthma Immunol 81:415–420(IIa), 1998). The classic symptoms of asthma include chest tightness, wheeze, cough, and dyspnea (Moorman et al., Vital Health Stat 3(35), 2012). The term asthma encompasses a spectrum of pulmonary diseases sharing the hallmark of reversible airway obstruction and can be classified as allergic or non-allergic (Löwhagen, J Asthma. 52(6):538–44, 2015). Asthma designated allergic is due to an immunoglobulin E (IgE)-mediated process, but as noted not all asthma is allergic in etiology (Romanet-Manent et al., Allergy 57:607–13, 2002). The differential diagnosis for asthma is broad and requires a detailed history with supportive pulmonary function tests to be properly diagnosed.

Epithelial folliculin enhances airway inflammation in aspirin-exacerbated respiratory disease

BACKGROUND

Clinical features of aspirin-exacerbated respiratory disease (AERD) are characterized by overproduction of cysteinyl leukotrienes (LT) and eosinophil activation, in which epithelial cells contribute to eosinophilic airway inflammation. Folliculin (FLCN) helps maintain the integrity of epithelial barrier, but little is known about FLCN in AERD.

OBJECTIVE

We investigated the role of FLCN in the pathogenic mechanisms of AERD.

METHODS

We recruited 178 subjects with AERD, 276 subjects with aspirin-tolerant asthma (ATA) and 71 normal healthy controls (NC) at Ajou Medical Center. Levels of FLCN and interleukin (IL)-8 in sera and supernatants were measured by ELISA. Peripheral blood eosinophils isolated from asthmatic patients were cocultured with human airway epithelial cells (HAECs) pretreated with LTE₄ , dexamethasone and montelukast. The intracellular expressions of FLCN, tight (TJ) (occludins, claudin-1) and adherens (AJ) junctions (E-cadherin) were analysed by Western blotting. shRNA was used to down-regulate FLCN (shFLCN) in HAECs.

RESULTS

Serum FLCN levels were significantly higher in AERD group than in ATA and NC groups (all P < 0.001). The cut-off value of 56.6 pg/mL was used to define the high FLCN phenotype (highFLCN). Asthmatic patients with highFLCN were associated with increased airway hyperresponsiveness to methacholine (P = 0.015). The serum FLCN level could discriminate AERD group from NC group with 82% sensitivity (AUC = 0.793, P < 0.001). When HAECs were exposed to LTE₄ , FLCN release was increased significantly (P < 0.05), which were amplified along with disruption of TJ and AJ expressions when HAECs were cocultured with eosinophils and LTE₄ (all P < 0.05); these effects were suppressed by dexamethasone and montelukast. FLCN knockdown reduced IL-8 release and occludin expression from shFLCN HAECs.

CONCLUSIONS

Our findings suggest that high LT and airway eosinophilia increased FLCN release from HAECs, which enhance epithelial activation and disruption. Modulation of FLCN may be a potential target for AERD.

MS4A2-rs573790 Is Associated With Aspirin-Exacerbated Respiratory Disease: Replicative Study Using a Candidate Gene Strategy

Aspirin exacerbated respiratory disease (AERD) is a set of diseases of the unified airway, and its physiopathology is related to disruption of the metabolism of arachidonic acid (AA). Genetic association studies in AERD had explored single nucleotide polymorphism (SNPs) in several genes related to many mechanisms (AA metabolism, inflammation, drug metabolism, etc.) but most lack validation stages in second populations. Our aim is to evaluated whether contribution to susceptibility of SNPs reported in other populations are associated with AERD in Mexican Mestizo patients. We developed a replicative study in two stages. In the first, 381 SNPs selected by fine mapping of associated genes, (previously reported in the literature), were integrated into a microarray and tested in three groups (AERD, asthma and healthy controls -HC-) using the GoldenGate array. Results associated to risk based on genetic models [comparing: AERD vs. HC (comparison 1, C1), AERD vs. asthma (C2), and asthma vs. HC (C3)] were validated in the second stage in other population groups using qPCR. In the first stage, we identified 11 SNPs associated with risk in C1.The top SNPs were ACE-rs4309C (p = 0.0001) and MS4A2-rs573790C (p = 0.0002). In C2, we detected 14 SNPs, including ACE-rs4309C (p = 0.0001). In C3, we found MS4A2-rs573790C (p = 0.001). Using genetic models, C1 MS4A2-rs57370 CC (p = 0.001), and ACE-rs4309 CC (p = 0.002) had associations. In C2 ACE-rs4309 CC (p = 0.0001) and C3 MS4A2-rs573790 CC (p = 0.001) were also associate with risk. In the second stage, only MS4A2-rs573790 CC had significance in C1 and C3 (p = 0.008 and p = 0.03). We concluded that rs573790 in the MS4A2 gene is the only SNP that supports an association with AERD in Mexican Mestizo patients in both stages of the study.

COX-1 mediates IL-33-induced extracellular signal-regulated kinase activation in mast cells: Implications for aspirin sensitivity

BACKGROUND

Classical FcεRI-induced mast cell (MC) activation causes synthesis of arachidonic acid (AA)-derived eicosanoids (leukotriene [LT] C₄, prostaglandin [PG] D₂, and thromboxane A₂), which mediate vascular leak, bronchoconstriction, and effector cell chemotaxis. Little is known about the significance and regulation of eicosanoid generation in response to nonclassical MC activation mechanisms.

OBJECTIVES

We sought to determine the regulation and significance of MC-derived eicosanoids synthesized in response to IL-33, a cytokine critical to innate type 2 immunity.

METHODS

We used an ex vivo model of mouse bone marrow-derived mast cells and an IL-33-dependent in vivo model of aspirin-exacerbated respiratory disease (AERD).

RESULTS

IL-33 potently liberates AA and elicits LTC₄, PGD₂, and thromboxane A₂ production by bone marrow-derived mast cells. Unexpectedly, the constitutive function of COX-1 is required for IL-33 to activate group IVa cytosolic phospholipase A₂ with consequent AA release for synthesis of all eicosanoids, including CysLTs. In contrast, COX-1 was dispensable for FcεRI-driven CysLT production. Inhibition of COX-1 prevented IL-33-induced phosphorylation of extracellular signal-related kinase, an upstream effector of cytosolic phospholipase A₂, which was restored by exogenous PGH₂, implying that the effects of COX-1 required its catalytic function. Administration of a COX-1-selective antagonist to mice completely prevented the generation of both PGD₂ and LTC₄ in a model of AERD in which MC activation is IL-33 driven.

CONCLUSIONS

MC-intrinsic COX-1 amplifies IL-33-induced activation in the setting of innate type 2 immunity and might help explain the phenomenon of therapeutic desensitization to aspirin by nonselective COX inhibitors in patients with AERD.

Asthma Phenotypes and Endotypes: Implications for Personalised Therapy

Asthma is increasingly recognised as a heterogeneous group of diseases with similar clinical presentations rather than a singular disease entity. Asthma was historically categorised by clinical symptoms; however, newer methods of subgrouping, describing and categorising the disease have sub-defined asthma. These sub-definitions are intermittently called phenotypes or endotypes, but the real meanings of these words are poorly understood. Novel treatments are currently and increasingly available, partly in the monoclonal antibody environment, and also some physical therapies (bronchial thermoplasty), but additionally small molecules are not far away from clinical practice. Understanding the disease pathogenesis and the mechanism of action more completely may enable identification of treatable traits, biomarkers, mediators and modifiable therapeutic targets. However, there remains a danger that clinicians become preoccupied with the concept of endotypes and biomarkers, ignoring therapies that are hugely effective but have no companion biomarker. This review discusses our understanding of the concept of phenotypes and endotypes in appreciating and managing the heterogeneous condition that is asthma. We consider the role of functional imaging, physiology, blood-, sputum- and breath-based biomarkers and clinical manifestations that could be used to produce a personalised asthma profile, with implications on prognosis, pathophysiology and most importantly specific therapeutic responses. With the advent of increasing numbers of biological therapies and other interventional options such as bronchial thermoplasty, the importance of targeting expensive therapies to patients with the best chance of clinical response has huge health economic importance.

Anaphylaxis in the 21st century: phenotypes, endotypes, and biomarkers

Anaphylaxis is the most serious of all allergic reactions and can be fatal. The diagnosis is frequently delayed, and misdiagnosis often occurs with asthma or urticaria. Biomarkers such as tryptase are not routinely checked, and appropriate treatment with epinephrine is not administered in a majority of cases, increasing the risk of poor outcomes. The objective of this review is to provide a better understanding of the pathophysiology of anaphylaxis with a description of phenotypes, endotypes, and biomarkers available in both the clinical and research settings. Expanding knowledge with regard to the presentation, causes, and triggers for anaphylaxis among health care providers will improve its diagnosis and management, increase patient safety, and decrease morbidity and mortality.

Immunoglobulin G4 sinusitis in association with aspirin-exacerbated respiratory disease

BACKGROUND

Immunoglobulin G4 (IgG4) related disease is a systemic inflammatory disease characterized by tumor-like tissue infiltration with IgG4 positive (IgG4+) plasma cells. Aspirin-exacerbated respiratory disease (AERD) is defined as asthma, chronic rhinosinusitis with nasal polyposis, and hypersensitivity to cyclooxygenase-1 inhibitors.

OBJECTIVE

We described a case of a non-smoking 61-year-old male with prior NSAID sensitivity who presented with a 1-year history of left eye proptosis associated with chronic nasal symptoms, ultimately identified as concurrent AERD and IgG4 sinusitis.

METHODS

The patient was evaluated in the clinic and diagnosed by using clinical, radiographic, and surgical biopsy findings.

RESULTS

Although initial concern was greatest for malignancy, a biopsy specimen confirmed the presence of a dense lymphoplasmacytic infiltrate and storiform fibrosis, associated with increased IgG4+ plasma cells. Therefore, IgG4-related disease (RD) was identified in this patient with AERD.

CONCLUSION

Shared type II inflammation may be responsible for the coexistence of IgG4-RD and AERD as observed in our patient. Health care workers must be cognizant of the simultaneous presentation of both IgG4-RD and AERD.

The Biological Activities of Oleocanthal from a Molecular Perspective

Oleocanthal is a minor constituent of olive oil with strong anti-inflammatory activities. Since the pathogenesis of many chronic diseases involves inflammatory and oxidative components, oleocanthal is a promising agent to prevent these conditions. This review aimed to summarise the current beneficial health effects of oleocanthal and the molecular basis of its biological actions. The anti-inflammatory, antioxidative, antimicrobial, anticancer and neuroprotective activities of oleocanthal have been examined by previous studies. Of these, studies on the anticancer effects have been the most extensive. Oleocanthal was reported to suppress melanoma, breast, liver, and colon cancer cells. Neurological studies focused on the effects of oleocanthal against Alzheimer’s disease. Oleocanthal improved clearance of the amyloid beta protein from neurons and reduced the inflammation of astrocytes. Despite the positive results, validation of the biological effects of oleocanthal in animal disease models is limited and should be emphasized in the future. As a conclusion, oleocanthal may act together with other bioactive compounds in olive oil to achieve its therapeutic potential. The use of oleocanthal alone as a single therapeutic measure awaits validation from future studies.

Aspirin-exacerbated respiratory disease: an update

PURPOSE OF REVIEW

The pathophysiology of aspirin-exacerbated respiratory disease (AERD) is not fully understood and diagnostic methods and so far, treatments for AERD have not been standardized. We summarize recent research into the pathological mechanisms of AERD, diagnostic methods, and treatments for AERD patients.

RECENT FINDINGS

In AERD pathophysiology, not only the reduced expression of E prostanoid 2 but also the dysfunction of its pathway could be involved. Moreover, eosinophils of AERD patients could be directly activated by aspirin to produce prostaglandin D2. Platelet activations are well known to be involved in AERD; however, plasma markers do not change during aspirin challenge tests. Additionally, novel genetic polymorphisms, such as P2RY12 and dipeptidyl peptidase 10 gene, and epigenetic predispositions of AERD were found. In AERD diagnosis, bronchial and nasal aspirin challenges have been applied in addition to oral challenge. Serum periostin has been suggested as a potential biomarker for AERD. Apart from standard pharmacological treatment and aspirin desensitization, biologics, including omalizumab and mepolizumab, as well as CRTH2 antagonists have been suggested as promising therapies for AERD treatment.

SUMMARY

AERD is usually associated with severe asthma phenotypes. AERD pathophysiology mainly involves the dysregulation of eicosanoid metabolisms, activations of effector cells, which could be influenced by genetic/epigenetic factors. Understanding the pathophysiology of AERD is key to improve the diagnostic methods and proper management of AERD patients.

Role of lipid mediators and control of lymphocyte responses in type 2 immunopathology

Type 2 immunopathology is a cardinal feature of allergic diseases and involves cooperation between adaptive immunity and innate effector responses. Virtually all cell types relevant to this pathology generate leukotriene and/or prostaglandin mediators that derive from arachidonic acid, express receptors for such mediators, or both. Recent studies highlight prominent functions for these mediators in communication between the innate and adaptive immune systems, as well as amplification or suppression of type 2 effector responses. This review focuses on recent advances and insights, and highlights existing and potential therapeutic applications of drugs that target these mediators or their receptors, with a special emphasis on their regulation of the innate and adaptive lymphocytes relevant to type 2 immunopathology.

Genetic and Epigenetic Components of Aspirin-Exacerbated Respiratory Disease

Aspirin-exacerbated respiratory disease (AERD) severity and its clinical phenotypes are characterized by genetic variation within pathways for arachidonic acid metabolism, inflammation, and immune responses. Epigenetic effects, including DNA methylation and histone protein modification, contribute to regulation of many genes that contribute to inflammatory states in AERD. The development of noninvasive, predictive clinical tests using data from genetic, epigenetic, pharmacogenetic, and biomarker studies will improve precision medicine efforts for AERD and asthma treatment.

Acquired Immunity in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a prevalent disease that is associated with significant costs and quality of life impairments. Currently, patients are classified into subgroups based on clinical characteristics, most often the presence or absence of nasal polyps. However, despite medical and surgical treatment, many of these patients continue to have symptoms. Recent efforts have focused on gaining a more complete understanding of the inflammatory mechanisms that drive pathogenesis in CRS, and it is becoming clear that the inflammatory processes in CRS are quite complex. As our understanding of these complex phenotypes improves, it may become possible to classify patients into endotypes based on unique inflammatory patterns within the sinus mucosa. This information may also lead to the identification of appropriate targeted therapies for different endotypes. This review will discuss our current understanding of endotypes in CRS along with the unique adaptive immune responses that may contribute to these different endotypes and, finally, some potential targeted therapeutics for the next generation of CRS treatment strategies.

Diagnosis and management of anaphylaxis in precision medicine

Anaphylaxis is the most severe and frightening of the allergic reactions, placing patients at high risk and demanding prompt recognition and immediate management by health care providers. Yet because its symptoms imitate those of other diseases, such as asthma and urticaria, current data suggest that its diagnosis is often missed, with underuse of tryptase measurement; its treatment is delayed, with little use of epinephrine; and its underlying cause or causes are poorly investigated. Deaths from anaphylaxis are difficult to investigate because of miscoding. Surprisingly, patients treated with new and powerful chemotherapy agents and humanized mAbs present with nonclassical symptoms of anaphylaxis, and patients may present with unrecognized clonal mast cell disorders with KIT mutations may present as Hymenoptera-induced or idiopathic anaphylaxis. The goal of this review is to recognize the presentations of anaphylaxis with the description of its current phenotypes, to provide new insight and understanding of its mechanisms and causes through its endotypes, and to address its biomarkers for broad clinical use. Ultimately, the aim is to empower allergists and heath care providers with new tools that can help alleviate patients' symptoms, preventing and protecting them against anaphylaxis.

Platelet-Eosinophil Interactions As a Potential Therapeutic Target in Allergic Inflammation and Asthma

The importance of platelet activation during hemostasis is well understood. An understanding of these mechanisms has led to the use of several classes of anti-platelet drugs to inhibit aggregation for the prevention of thrombi during cardiovascular disease. It is now also recognized that platelets can function very differently during inflammation, as part of their role in the innate immune response against pathogens. This dichotomy in platelet function occurs through distinct physiological processes and alternative signaling pathways compared to that of hemostasis (leading to platelet aggregation) and is manifested as increased rheological interactions with leukocytes, the ability to undergo chemotaxis, communication with antigen-presenting cells, and direct anti-pathogen responses. Mounting evidence suggests platelets are also critical in the pathogenesis of allergic diseases such as asthma, where they have been associated with antigen presentation, bronchoconstriction, bronchial hyperresponsiveness, airway inflammation, and airway remodeling in both clinical and experimental studies. In particular, platelets have been reported bound to eosinophils in the blood of patients with asthma and the incidence of these events increases after both spontaneous asthma attacks in a biphasic manner, or after allergen challenge in the clinic. Platelet depletion in animal models of allergic airway inflammation causes a profound reduction in eosinophil recruitment to the lung, suggesting that the association of platelets with eosinophils is indeed an important event during eosinophil activation. Furthermore, in cases of severe asthma, and in animal models of allergic airways inflammation, platelet–eosinophil complexes move into the lung through a platelet P-selectin-mediated, eosinophil β1-integrin activation-dependent process, while platelets increase adherence of eosinophils to the vascular endothelium in vitro, demonstrating a clear interaction between these cell types in allergic inflammatory diseases. This review will explore non-thrombotic platelet activation in the context of allergy and the association of platelets with eosinophils, to reveal how these phenomena may lead to the discovery of novel therapeutic targets.

Lipid Mediators of Allergic Disease: Pathways, Treatments, and Emerging Therapeutic Targets

Bioactive lipids are critical regulators of inflammation. Over the last 75 years, these diverse compounds have emerged as clinically-relevant mediators of allergic disease pathophysiology. Animal and human studies have demonstrated the importance of lipid mediators in the development of asthma, allergic rhinitis, urticaria, anaphylaxis, atopic dermatitis, and food allergy. Lipids are critical participants in cell signaling events which influence key physiologic (bronchoconstriction) and immune phenomena (degranulation, chemotaxis, sensitization). Lipid-mediated cellular mechanisms including: (1) formation of structural support platforms (lipid rafts) for receptor signaling complexes, (2) activation of a diverse family of G-protein coupled receptors, and (3) mediating intracellular signaling cascades by acting as second messengers. Here, we review four classes of bioactive lipids (platelet activating factor, the leukotrienes, the prostanoids, and the sphingolipids) with special emphasis on lipid synthesis pathways and signaling, atopic disease pathology, and the ongoing development of atopy treatments targeting lipid mediator pathways.

Clinical Characteristics of Patients with Chronic Rhinosinusitis with Nasal Polyps, Asthma, and Aspirin-Exacerbated Respiratory Disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) comprises the triad of chronic rhinosinusitis with nasal polyps (CRSwNP), asthma, and intolerance to inhibitors of the cyclooxygenase-1 (COX-1) enzyme. The prevalence of AERD remains unclear, and few studies have compared the clinical characteristics of patients with AERD to those with CRSwNP alone, asthma alone, or both CRSwNP and asthma.

OBJECTIVE

To determine the prevalence of AERD within a tertiary care setting, and to identify unique clinical features that could distinguish these patients from those with both CRSwNP and asthma or with CRSwNP alone.

METHODS

Electronic medical records of patients at Northwestern in Chicago, Illinois, were searched by computer algorithm and then manual chart review to identify 459 patients with CRSwNP alone, 412 with both CRSwNP and asthma, 171 with AERD, and 300 with asthma only. Demographic and clinical features including sex, atopy, and sinus disease severity were characterized.

RESULTS

The prevalence of AERD among patients with CRSwNP was 16%. Patients with AERD had undergone 2-fold more sinus surgeries (P < .001) and were significantly younger at the time of their first surgery (40 ± 13 years) than were patients with CRSwNP (43 ± 14 years; P < .05). Atopy was significantly more prevalent in patients with AERD (84%) or asthma (85%) than in patients with CRSwNP (66%, P < .05). More patients with AERD (13%) had corticosteroid-dependent disease than patients with both CRSwNP and asthma (4%, P < .01) or asthma (1%, P < .001).

CONCLUSIONS

AERD is common among patients with CRSwNP; even though patients with AERD have CRSwNP and asthma, the clinical course of their disease is not the same as of patients who have CRSwNP and asthma but are tolerant to COX-1 inhibitors.

Cyclooxygenase 2: its regulation, role and impact in airway inflammation

Cyclooxygenase 2 (COX-2: official gene symbol - PTGS2) has long been regarded as playing a pivotal role in the pathogenesis of airway inflammation in respiratory diseases including asthma. COX-2 can be rapidly and robustly expressed in response to a diverse range of pro-inflammatory cytokines and mediators. Thus, increased levels of COX-2 protein and prostanoid metabolites serve as key contributors to pathobiology in respiratory diseases typified by dysregulated inflammation. But COX-2 products may not be all bad: prostanoids can exert anti-inflammatory/bronchoprotective functions in airways in addition to their pro-inflammatory actions. Herein, we outline COX-2 regulation and review the diverse stimuli known to induce COX-2 in the context of airway inflammation. We discuss some of the positive and negative effects that COX-2/prostanoids can exert in in vitro and in vivo models of airway inflammation, and suggest that inhibiting COX-2 expression to repress airway inflammation may be too blunt an approach; because although it might reduce the unwanted effects of COX-2 activation, it may also negate the positive effects. Evidence suggests that prostanoids produced via COX-2 upregulation show diverse actions (and herein we focus on prostaglandin E2 as a key example); these can be either beneficial or deleterious and their impact on respiratory disease can be dictated by local concentration and specific interaction with individual receptors. We propose that understanding the regulation of COX-2 expression and associated receptor-mediated functional outcomes may reveal number of critical steps amenable to pharmacological intervention. These may prove invaluable in our quest towards future development of novel anti-inflammatory pharmacotherapeutic strategies for the treatment of airway diseases.

Dietary modifications for refractory chronic rhinosinusitis? Manipulating diet for the modulation of inflammation

BACKGROUND

An endotype of chronic rhinosinusitis (CRS) refractory to medical and surgical management is characterized by persistent T-helper 1/T-helper 17 inflammation of the sinus mucosa, which potentially facilitates colonization with dysbiotic microbial flora. Dietary interventions that target reduction of systemic inflammation are increasingly recommended as adjuncts to ongoing medical therapy in chronic disorders with a strong inflammatory component, such as cardiac disease, diabetes, and metabolic syndrome. Inflammation-reducing dietary modifications may thus be of benefit in patients with refractory CRS (RCRS).

OBJECTIVE

To identify nonpharmacologic approaches that implicate modification of dietary factors, potentially reducing systemic level of inflammation in RCRS.

METHODS

A systematic review of the literature was undertaken to identify dietary strategies for reducing inflammation in metabolic syndrome, diabetes, and cardiac disease. Mechanistic-based strategies for reducing systemic inflammation were identified and categorized to identify potential therapeutic avenues, which would be applicable to RCRS.

RESULTS

Principal mechanisms for altering inflammation at the systemic level via dietary manipulation center around (1) increased consumption of foods with anti-inflammatory properties, and (2) modulation of the gut microbiome to reduce short-chain fatty acid secretion by dysbiotic gut flora. Recommended dietary modifications to reduce systemic markers of inflammation or to improve RCRS include alteration of macronutrient intake, alterations in consumption of meat and fats, consumption of prebiotics and probiotics, and a low-salicylate diet in the context of aspirin-exacerbated respiratory disease.

CONCLUSION

Dietary modifications may offer a potential nonpharmacologic means of reducing inflammation in patients with RCRS and hence may represent a complementary adjunct to existing medical therapies. Additional prospective studies are required to further validate the concept of dietary modifications in patients with RCRS to support the findings.

Montelukast, current indications and prospective future applications

INTRODUCTION

Montelukast is recommended for the treatment of asthma, exercise -induced bronchospasm and allergic rhinitis. Several trials demonstrated potential therapeutic effects in other respiratory conditions, and different animal-model-based studies explored potential pharmacological actions in non-respiratory conditions.

AREAS COVERED

Clinical investigations on the pharmacotherapeutic effects of montelukast, in addition to in-vivo studies on animal models of non-respiratory diseases. The data discussed in this review were mainly obtained from clinical randomized trials, real-life studies, and studies based on animal models as approve of concept. As a condition, all of the discussed articles were published in journals cited by Pubmed. Expert commentary: The current clinical data are in favor of montelukast use in the management of chronic asthma as an add-on or alternative therapy to the inhaled corticosteroids. Further clinical trials are required to confirm the effectiveness and feasibility of montelukast for the treatment of conditions other than the current clinical indications.

Chronic Rhinosinusitis with Nasal Polyps

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an important clinical entity diagnosed by the presence of both subjective and objective evidence of chronic sinonasal inflammation. Symptoms include anterior or posterior rhinorrhea, nasal congestion, hyposmia, and/or facial pressure or pain that last for a duration of more than 12 weeks. Nasal polyps are inflammatory lesions that project into the nasal airway, are typically bilateral, and originate from the ethmoid sinus. Males are more likely to be affected than females, but no specific genetic or environmental factors have been strongly linked to the development of this disorder to date. CRSwNP is frequently associated with asthma and allergic rhinitis, but the cellular and molecular mechanisms that contribute to the clinical symptoms are not fully understood. Defects in the sinonasal epithelial cell barrier, increased exposure to pathogenic and colonized bacteria, and dysregulation of the host immune system are all thought to play prominent roles in disease pathogenesis. Additional studies are needed to further explore the clinical and pathophysiological features of CRSwNP so that biomarkers can be identified and novel advances can be made to improve the treatment and management of this disease.

Immediate hypersensitivity reactions to ibuprofen and other arylpropionic acid derivatives

BACKGROUND

Although ibuprofen and other arylpropionic acid derivatives (APs) are the most common medicines involved in hypersensitivity drug reactions (HDRs) to NSAIDs, no patient series studies have been performed regarding immediate selective reactions (SRs) to these drugs.

OBJECTIVE

To characterize patients with immediate selective HDRs to ibuprofen and other APs through clinical history and challenge.

METHODS

Subjects who developed an HDR to APs less than 1 h after drug intake were included. Tolerance to aspirin was assessed and challenge was performed with ibuprofen in all cases, and additionally with the culprit drug (if different) in those patients that tolerated ibuprofen. Serum tryptase levels and tryptase immunohistochemical staining in skin biopsies were also assessed in some patients with a positive DPT to ibuprofen.

RESULTS

From a total of 245 patients with a confirmed history of HDRs to APs, 17% were classified as selective immediate hypersensitivity reactors by both clinical history and challenge. A selective response to naproxen and dexketoprofen with tolerance to ibuprofen was found in 16 of 20 cases. Significant differences in serum tryptase levels were observed between 2 and 24 h in the 11 cases that were studied further.

CONCLUSIONS

Within the group of patients with HDRs to NSAIDs, APs can induce immediate SRs. Within this group, selective responses to a single drug or responders to several APs may exist, suggesting potential immunological cross-reactivity.

Insights into Group 2 Innate Lymphoid Cells in Human Airway Disease

Recent discoveries have led to the identification of a novel group of immune cells, the innate lymphoid cells (ILCs). The members of this group are divided into three subpopulations: ILC1s, ILC2s, and ILC3s. ILC2s produce Th2 cytokines, IL-4, IL-5, and IL-13, upon activation by epithelial cell-derived cytokines, lipid mediators (cysteinyl leukotrienes and prostaglandin D2), and TNF family member TL1A and promote structural and immune cell responses in the airways after antigen exposure. In addition, ILC2 function is also influenced by inducible T cell costimulator (ICOS)/ICOS-ligand (ICOS-L) interactions via direct contact between immune cells. The most common airway antigens are allergens and viruses which are highly linked to the induction of airway diseases with underlying type 2 inflammation including asthma and allergic rhinitis. Based on recent findings linking ILC2s and airway Th2 responses, there is intensive investigation into the role of ILC2s in human disease with the hope of a better understanding of the pathophysiology and the discovery of novel potential therapeutic targets. This review summarizes the recent advances made in elucidating ILC2 involvement in human Th2 airway disease.

Cytokines in Chronic Rhinosinusitis. Role in Eosinophilia and Aspirin-exacerbated Respiratory Disease

RATIONALE

The mechanisms that underlie the pathogenesis of chronic rhinosinusitis without nasal polyps (CRSsNP), chronic rhinosinusitis with nasal polyps (CRSwNP), and aspirin-exacerbated respiratory disease (AERD) are not clear.

OBJECTIVES

To first evaluate the inflammatory profiles of CRSsNP and CRSwNP tissues and then to investigate whether clinical differences observed between CRSwNP and AERD are in part secondary to differences in inflammatory mediator expression within nasal polyp (NP) tissues.

METHODS

Expression levels of numerous inflammatory mediators were determined by quantitative real-time polymerase chain reaction, ELISA, and multiplex immunoassay.

MEASUREMENTS AND MAIN RESULTS

CRSwNP NP had increased levels of type 2 mediators, including IL-5 (P < 0.001), IL-13 (P < 0.001), eotaxin-2 (P < 0.001), and monocyte chemoattractant protein (MCP)-4 (P < 0.01), compared with sinonasal tissue from subjects with CRSsNP and control subjects. Expression of IFN-γ messenger RNA or protein was low and not different among the chronic rhinosinusitis subtypes examined. Compared with CRSwNP, AERD NP had elevated protein levels of eosinophil cationic protein (ECP) (P < 0.001), granulocyte-macrophage colony-stimulating factor (GM-CSF) (P < 0.01), and MCP-1 (P = 0.01), as well as decreased gene expression of tissue plasminogen activator (tPA) (P = 0.02). Despite the higher eosinophilia in AERD, there was no associated increase in type 2 mediator protein levels observed.

CONCLUSIONS

CRSwNP was characterized by a predominant type 2 inflammatory environment, whereas CRSsNP did not reflect a classic type 1 milieu, as has been suggested previously. AERD can be distinguished from CRSwNP by elevated ECP levels, but this enhanced eosinophilia is not associated with elevations in traditional type 2 inflammatory mediators associated with eosinophil proliferation and recruitment. However, other factors, including GM-CSF, MCP-1, and tPA, may be important contributors to AERD pathogenesis.

Low E-prostanoid 2 receptor levels and deficient induction of the IL-1β/IL-1 type I receptor/COX-2 pathway: Vicious circle in patients with aspirin-exacerbated respiratory disease

BACKGROUND

We hypothesized that the 2 reported alterations in aspirin-exacerbated respiratory disease (AERD), reduced expression/production of COX-2/prostaglandin (PG) E2 and diminished expression of E-prostanoid (EP) 2 receptor, are closely linked.

OBJECTIVE

We sought to determine the mechanisms involved in the altered regulation of the COX pathway in patients with AERD.

METHODS

Fibroblasts were obtained from nasal mucosa; samples of control subjects (NM-C, n = 8) and from nasal polyps from patients with aspirin-exacerbated respiratory disease (NP-AERD, n = 8). Expression of the autocrine loop components regulating PGE2 production and signaling, namely IL-1 type I receptor (IL-1RI), COX-2, microsomal prostaglandin E synthase 1 (mPGES-1), and EP receptors, was assessed at baseline and after stimulation with IL-1β, PGE2, and specific EP receptor agonists.

RESULTS

Compared with NM-C fibroblasts, basal expression levels of IL-1RI and EP2 receptor were lower in NP-AERD fibroblasts. IL-1β-induced IL-1RI, COX-2, and mPGES-1 expression levels were also lower in these cells. Levels of IL-1RI positively correlated with COX-2 and mPGES-1 expression in both NM-C and NP-AERD fibroblasts. Incubation with either exogenous PGE2 or selective EP2 agonist significantly increased expression of IL-1RI in NM-C fibroblasts and had hardly any effect on NP-AERD fibroblasts. Alterations in IL-1RI, COX-2, and mPGES-1 expression that were found in NP-AERD fibroblasts were corrected when EP2 receptor expression was normalized by transfection of NP-AERD fibroblasts.

CONCLUSION

Altered expression of EP2 in patients with AERD contributes to deficient induction of IL-1RI, reducing the capacity of IL-1β to increase COX-2 and mPGES-1 expression, which results in low PGE2 production. This impairment in the generation of PGE2 subsequently reduces its ability to induce IL-1RI.

Pathogenesis of nasal polyposis

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex inflammatory condition that affects a large proportion of the population world-wide and is associated with high cost of management and significant morbidity. Yet, there is a lack of population-based epidemiologic studies using current definitions of CRSwNP, and the mechanisms that drive pathogenesis in this disease remain unclear. In this review, we summarize the current evidence for the plethora of factors that likely contribute to CRSwNP pathogenesis. Defects in the innate function of the airway epithelial barrier, including diminished expression of antimicrobial products and loss of barrier integrity, combined with colonization by fungi and bacteria likely play a critical role in the development of chronic inflammation in CRSwNP. This chronic inflammation is characterized by elevated expression of many key inflammatory cytokines and chemokines, including IL-5, thymic stromal lymphopoietin and CCL11, that help to initiate and perpetuate this chronic inflammatory response. Together, these factors likely combine to drive the influx of a variety of immune cells, including eosinophils, mast cells, group 2 innate lymphoid cells and lymphocytes, which participate in the chronic inflammatory response within the nasal polyps. Importantly, however, future studies are needed to demonstrate the necessity and sufficiency of these potential drivers of disease in CRSwNP. In addition to the development of new tools and models to aid mechanistic studies, the field of CRSwNP research also needs the type of robust epidemiologic data that has served the asthma community so well. Given the high prevalence, costs and morbidity, there is a great need for continued research into CRS that could facilitate the development of novel therapeutic strategies to improve treatment for patients who suffer from this disease.