Update on Aspirin-Exacerbated Respiratory Disease

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?

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.

IL-4/IFN-γ inflammatory cytokine profile induces a deficient regulation of the IL-1β/IL-1RI/EP2/COX-2 pathway in nasal mucosa

BACKGROUND

We hypothesized that the peculiar mixed interleukin-4 (IL-4/Th2) and interferon gamma INF-γ (INF-γ/Th1) inflammatory milieu found in the airways of patients with aspirin-exacerbated respiratory disease (AERD) is responsible for the altered regulation of the IL-1β/IL-1RI-/EP₂/COX-2 autocrine loop also found in these patients. The objective of the study is to demonstrate that IL-4 and INF-γ cytokines, are capable of inducing in healthy nasal mucosa (NM) the dysregulation of the autocrine loop of COX reported in AERD.

SUBJECTS AND METHODS

Fibroblasts were obtained from NM (n = 8). To evaluate the role of IL-4 and IFN-γ on the autocrine loop, fibroblasts were incubated with or without IL-1β, in the presence or absence of IL-4 and/or IFN-γ for 48 h. After this period, the expression of EP₂, EP₃, EP₄, IL-1RI, COX-2 and mPGES-1 was measured by Western blot.

RESULTS

Stimulation of fibroblasts with IL-1β significantly increased the expression of EP₂, but had no effects on EP₃ and EP₄ expression Incubation with IL-4 or IFN-γ alone was not able to modify the expression of any of the components of the autocrine loop. In contrast, co-treatment with IL-4 and IFN-γ was able to significantly inhibit IL-1β-induced EP₂, IL-1RI, COX-2 and mPGES-1.

CONCLUSION

These results suggest that the mixed Th1/Th2 inflammatory pattern found in the airways of AERD patients might be responsible for the altered regulation of the COX pathway also reported in these asthma patients.

Characteristics of NSAID-induced hypersensitivity reactions in childhood

Non-steroidal anti-inflammatory drugs (NSAIDs) are available as over-the-counter drugs, and they are commonly used in children for their antipyretic, analgesic, and anti-inflammatory effects. NSAIDs are among the most frequently reported drugs associated with hypersensitivity reactions and even with anaphylaxis. A complete evaluation of the patients based on reported clinical manifestations, timing of the reaction, the presence of underlying disease, and reactions to other NSAIDs allows clinicians to stratify children with a history of reaction to NSAIDs. Although NSAID-induced hypersensitivity reactions have mainly been investigated in adults, recent studies have aimed to explore their epidemiology in the pediatric population. This review will cover the current understanding of clinical manifestations, the risk factors, and the different phenotypes of NSAID-induced hypersensitivity reactions with a comprehensive overview of the epidemiologic data from past to present and the practical approach to the management of NSAID hypersensitivity in children and adolescents.

Airway innate lymphoid cells in the induction and regulation of allergy

The recent discovery of innate lymphoid cells has revolutionized our understanding of the pathogenesis of immune diseases including allergy and asthma. Innate lymphoid cells (ILCs) are a heterogeneous collection of lymphocytes that lack antigen-specificity (non-T, non-B cells) and potently produce characteristic cytokines of T cell subsets (Th1, Th2, Th17). ILCs are divided into group 1 (ILC1s), group 2 (ILC2s), or group 3 (ILC3s). Similar to Th2 cells, ILC2s produce IL-4, IL-5, and IL-13, among others, and are present in increased numbers in samples from patients with many allergic disorders including asthma and chronic rhinosinusitis (CRS). Animal models have identified that ILC2s contribute to eosinophilic tissue infiltration, airway hyperresponsiveness, mucus production, as well as coordinate adaptive immune responses. Finally, recent studies support regulation of ILC2s by neuro-immune mechanisms as well as demonstrate a significant degree of plasticity between ILC subsets that may impact the immune responses in asthma and allergic airway diseases. Here, we review the current literature on ILC2s in human asthma and allergic airway diseases, as well as highlight some recent mechanistic insights into ILC2 function from in vitro studies and in vivo animal models.

Role of group 2 innate lymphocytes in aspirin-exacerbated respiratory disease pathogenesis

Aspirin-exacerbated respiratory disease (AERD) is characterized by chronic eosinophilic nasal polyps, asthma, and airway reactions upon cyclooxygenase (COX) 1 inhibition. AERD is present in up to 7% of adult patients with asthma and the underlying pathogenesis remains largely elusive but prostaglandin D2, cysteinyl leukotrienes, mast cells, and type 2 cytokines are thought to contribute. A wealth of studies have recently implicated group 2 innate lymphoid cells (ILC2), a novel lineage-negative lymphocyte population that produces type 2 cytokines, in human allergic disease pathogenesis. Importantly, our recent work identified that ILC2s are recruited to the nasal mucosa of patients on AERD after COX-1 inhibitor administration. Here, we review the potential impact of ILC2s in the development and propagation of type 2 inflammation in AERD.

Contribution of Host Defence Proteins and Peptides to Host-Microbiota Interactions in Chronic Inflammatory Lung Diseases

The respiratory tract harbours a variety of microorganisms, collectively called the respiratory microbiota. Over the past few years, alterations in respiratory and gut microbiota composition have been associated with chronic inflammatory diseases of the lungs. How these changes influence disease development and progression is an active field of investigation. Identifying and understanding host-microbiota interactions and factors contributing to these interactions could promote the development of novel therapeutic strategies aimed at restoring host-microbiota homeostasis. In this review, we discuss recent literature on host-microbiota interactions in the respiratory tract, with a specific focus on the influence of endogenous host defence peptides and proteins (HDPs) on the composition of microbiota populations in vivo and explore possible HDPs-related therapeutic approaches targeting microbiota dysbiosis in chronic inflammatory lung diseases.

Cortactin expression in nasal polyps of Aspirin-Exacerbated Respiratory Disease (AERD) patients

PURPOSE

The term aspirin-exacerbated respiratory disease (AERD) refers to a combination of asthma, chronic rhinosinusitis with nasal polyposis (CRSwNP), and acute respiratory tract reactions to nonsteroidal anti-inflammatory drugs. AERD has now been included among the CRSwNP endotypes, and is considered one of the most aggressive in terms of disease recurrence. Cortactin is a multi-domain protein with a part in several cellular mechanisms involving actin assembly and cytoskeleton arrangement. Cortactin seems to have a role in inflammatory responses and to be implicated in human airway secretion and contraction mechanisms. The novel aim of the present study was to examine cortactin expression in nasal polyps of a consecutive cohort of AERD patients and in nasal mucosa of a control group of patients.

MATERIALS AND METHODS

Cortactin expression was assessed immunohistochemically in nasal polyps from 18 consecutive AERD patients who underwent endoscopic sinus surgery and in nasal mucosa of 19 patients without chronic rhinosinusitis.

RESULTS

Concomitant allergy was found in 11 AERD patients, most of them male (8 cases; p = 0.02). Cortactin expression in nasal polyps was definitely high (+3) in 17 out of 18 cases, in both epithelial cells (cytoplasmic and membranous immunoreactivity) and activated fibroblasts. A higher cortactin expression was seen in female than in male AERD patients (p = 0.05).

CONCLUSIONS

Given this preliminary evidence of cortactin upregulation in the polyps of AERD patients, prospective studies could further investigate the role of cortactin in the biology of AERD, and the potential role of cortactin-targeted approaches in integrated AERD treatments.

Factors correlated with repeated aspirin dosing during aspirin desensitization

BACKGROUND

Aspirin desensitization is an appropriate procedure for many patients with aspirin-exacerbated respiratory disease (AERD). Patients can require aspirin re-dosing, which prolongs the desensitization process. The frequency of this is not widely reported, nor is it known which patients will require multiple re-dosing.

OBJECTIVE

To determine the frequency of and factors associated with repeat aspirin re-dosing during desensitization.

METHODS

Charts of aspirin desensitization procedures from 2011 to 2016 at the University of Michigan Allergy/Immunology Clinic were reviewed. Reactions with provoking doses and number of dose repetitions were characterized. Previous AERD history, medical history, medications, and baseline spirometry were also recorded. Bivariate correlation and multivariate logistic regression were used to analyze associations between patient characteristics and need for repeated dosing of aspirin.

RESULTS

A total of 84 positive-reacting patients during desensitization were identified. Of these patients, 33% required 2 or more aspirin dose repetitions during desensitization. Requiring 2 or more repeat doses during desensitization was associated with male gender (odds ratio = 6.194, P = .008), forced expiratory volume in 1 second (FEV₁) decrease during desensitization (odds ratio = 1.075 per percent point drop, P = .021), and initial aspirin provoking dose during desensitization of 81 mg or lower (odds ratio = 11.111, P = .003). No association was found with pre-desensitization medications, asthma severity, AERD duration, or number/character of reported previous aspirin reactions.

CONCLUSION

During aspirin desensitization for AERD, approximately one third of our patients require multiple repeat doses. Risk factors for multiple repeated doses include male gender, drop in FEV₁, and lower aspirin provoking doses during desensitization. This information can help inform which patients may require multiple re-dosing for desensitization.

Aspirin challenge and desensitization: how, when and why

PURPOSE OF REVIEW

To investigate the current approach to aspirin challenge (drug provocation) and/or desensitization in patients with histories of hypersensitivity reactions to it, particularly in those with cardiovascular diseases.

RECENT FINDINGS

The literature indicates that patients with coronary artery disease (CAD), including those with an acute coronary syndrome, may safely undergo low-dose aspirin challenge and/or desensitization. Recently, flowcharts regarding challenge/desensitization procedures with aspirin in patients with CAD and histories of aspirin hypersensitivity reactions have become available. Aspirin desensitization and continuous aspirin therapy constitute an effective option in patients with nonsteroidal anti-inflammatory drug-exacerbated respiratory diseases (NERD) who have suboptimally controlled asthma or rhinosinusitis, or require multiple revision polypectomies.

SUMMARY

The use of aspirin has proven to reduce morbidity and mortality associated with CAD. There is a general consensus on aspirin's effectiveness in secondary prevention of CAD. Therefore, aspirin desensitization is necessary in patients with CAD and histories of hypersensitivity reactions to it. The effectiveness of aspirin desensitization and continuous therapy in patients with NERD has been shown in numerous studies. However, shared selection criteria of candidates for aspirin challenge/desensitization procedures, and simple and homogeneous protocols are necessary. Moreover, preventive safety measures are still needed in order to reduce the potential risks of these procedures.

Asthma in the elderly and late-onset adult asthma

Elderly asthmatics are at a higher risk for morbidity and mortality from their asthma than younger patients. There are important age-related physiologic and immunologic changes that complicate the presentation, diagnosis, and management of asthma in the aged population. Evidence suggests that elderly asthmatics are more likely to be underdiagnosed and undertreated. Additionally, elderly patients with asthma have highest rates of morbidity and mortality from their disease than younger patients. The underlying airway inflammation of asthma in this age group likely differs from younger patients and is felt to be non-type 2 mediated. While elderly patients are underrepresented in clinical trials, subgroup analysis of large clinical trials suggests they may be less likely to respond to traditional asthma therapies (ie, corticosteroids). As the armamentarium of pharmacologic asthma therapies expands, it will be critical to include elderly asthmatics in large clinical trials so that therapy may be better tailored to this at-risk and growing population.

Aspirin exacerbated respiratory disease: Current topics and trends

Aspirin-exacerbated respiratory disease is a chronic and treatment-resistant disease, characterized by the presence of eosinophilic rhinosinusitis, nasal polyposis, bronchial asthma, and nonsteroidal anti-inflammatory drugs hypersensitivity. Alterations in arachidonic acid metabolism may induce an imbalance between pro-inflammatory and anti-inflammatory substances, expressed as an overproduction of cysteinyl leukotrienes and an underproduction of prostaglandin E2. Although eosinophils play a key role, recent studies have shown the importance of other cells and molecules in the development of the disease like mast cells, basophils, lymphocytes, platelets, neutrophils, macrophages, epithelial respiratory cells, IL-33 and thymic stromal lymphopoietin, making each of them promissory diagnostic and treatment targets. In this review, we summarize the most important clinical aspects of the disease, including the current topics about diagnosis and treatment, like provocation challenges and aspirin desensitization. We also discuss recent findings in the pathogenesis of the disease, as well as future trends in diagnosis and treatment, including monoclonal antibodies and a low salicylate diet as a treatment option.

Cytokine and Lipid Mediator Regulation of Group 2 Innate Lymphoid Cells (ILC2s) in Human Allergic Airway Disease

The recent discovery of group 2 innate lymphoid cells (ILC2s) has caused a paradigm shift in the understanding of allergic airway disease pathogenesis. Prior to the discovery of ILC2s, Th2 cells were largely thought to be the primary source of type 2 cytokines; however, activated ILC2s have since been shown to contribute significantly, and in some cases, dominantly to type 2 cytokine production. Since the discovery of ILC2s in 2010, many mediators have been shown to regulate their effector functions. Initial studies identified the epithelial derived cytokines IL-25, IL-33, and TSLP as activators of ILC2s, and recent studies have identified many additional cytokine and lipid mediators that are involved in ILC2 regulation. ILC2s and their mediators represent novel therapeutic targets for allergic airway diseases and intensive investigation is underway to better understand ILC2 biology and upstream and downstream pathways that lead to ILC2-driven airway pathology. In this review, we will focus on the cytokine and lipid mediators that regulate ILC2s in human allergic airway disease, as well as highlight newly discovered mediators of mouse ILC2s that may eventually translate to humans.

Prostaglandins and Their Receptors in Eosinophil Function and As Therapeutic Targets

Of the known prostanoid receptors, human eosinophils express the prostaglandin D₂ (PGD₂) receptors DP1 [also D-type prostanoid (DP)] and DP2 (also chemoattractant receptor homologous molecule, expressed on Th2 cells), the prostaglandin E₂ receptors EP2 and EP4, and the prostacyclin (PGI₂) receptor IP. Prostanoids can bind to either one or multiple receptors, characteristically have a short half-life in vivo, and are quickly degraded into metabolites with altered affinity and specificity for a given receptor subtype. Prostanoid receptors signal mainly through G proteins and naturally activate signal transduction pathways according to the G protein subtype that they preferentially interact with. This can lead to the activation of sometimes opposing signaling pathways. In addition, prostanoid signaling is often cell-type specific and also the combination of expressed receptors can influence the outcome of the prostanoid impulse. Accordingly, it is assumed that eosinophils and their (patho-)physiological functions are governed by a sensitive prostanoid signaling network. In this review, we specifically focus on the functions of PGD₂, PGE₂, and PGI₂ and their receptors on eosinophils. We discuss their significance in allergic and non-allergic diseases and summarize potential targets for drug intervention.