Aspirin sensitivity: Lessons in the regulation (and dysregulation) of mast cell function

Acetylsalicylic acid aggravates anaphylaxis in a PGE2-dependent manner

Acetylsalicylic acid (ASA) can exert proanaphylactic effects, but the extent of this phenomenon and its underlying mechanisms are undefined. Yet, low homeostatic prostaglandin E2 (PGE2) levels have been associated with anaphylaxis. In this study, we investigated whether the proanaphylactic effect of ASA is PGE2 dependent. We assessed the effect of ASA in experimental anaphylaxis models, analyzed a large dataset of patients with anaphylaxis, and performed titrated allergen challenges in ASA-treated allergic individuals. Registry data indicated an increased risk for severe anaphylaxis in patients with ASA comedication. ASA pretreatment aggravated allergen-dependent anaphylaxis in mice, whereas histamine-induced anaphylaxis remained unaffected. Exacerbation was due to reduced PGE2, as its stabilization or the use of prostanoid E receptor (EP) agonists reversed the proanaphylactic effects of ASA. EP2-, EP3-, and EP4 receptor-deficient mice revealed that each receptor individually contributed to ASA susceptibility. In patients with allergy, prior ASA intake increased skin responsiveness to allergen but not to histamine. Conversely, the responses of basophils to ex vivo FcεRI aggregation remained unaltered, indicating that ASA operated by enhancing the stimulability of mast cells in a PGE2-dependent manner. Collectively, our data reveal a central role of the PGE2 network in ASA-aggravated anaphylaxis. EP receptors could be potential targets to prevent or alter the outcome of anaphylaxis.

Critical pathomechanisms of NSAID-exacerbated respiratory disease (N-ERD) clarified by treatment with omalizumab, an anti-IgE antibody

Characteristic symptoms of NSAID-exacerbated respiratory disease (N-ERD) include asthma, chronic eosinophilic rhinosinusitis with nasal polyposis, cysteinyl LT (CysLT) overproduction and NSAIDs hypersensitivity. Some N-ERD patients present with episodic treatment-resistant extra-respiratory symptoms (CysLT-associated coronary artery vasospasm, gastroenteritis, or skin rash). Even when using standard treatments for respiratory and extra-respiratory symptoms, including systemic corticosteroids and aspirin desensitization, it is difficult to control the clinical symptoms and severe type 2 inflammation involved with mast cells, eosinophils, ILC2s, and platelet activation. Few treatment options are applicable in a clinical setting. Therefore, identifying effective treatments is essential for managing N-ERD patients who suffer from these conditions. Our previous observational study demonstrated 12-month omalizumab treatment of N-ERD was clinically effective against respiratory symptoms. Despite the remaining eosinophilia, omalizumab significantly reduced urinary LTE4 and PGD2 metabolites to near normal levels at steady state. Based on the preliminary study, we demonstrated that omalizumab induced tolerance to aspirin in N-ERD patients 3 months after therapy initiation and suppressed activation of mast cells during 24 h of initiation in a randomized manner. Moreover, omalizumab had significant efficacy against extra-respiratory symptoms at baseline (lacking aspirin exposure) as well as throughout aspirin challenge. This review addresses the latest discoveries related to N-ERD pathogenesis and the significant effectiveness of omalizumab on N-ERD as a mast cell stabilizer. Our findings regarding omalizumab-associated mast cell inhibitory effects are indirect evidence that mast cell dysregulation and, possibly, IgE are pivotal components of N-ERD.

Aspirin Hypersensitivity in Patients With Atherosclerotic Cardiovascular Disease

Low-dose aspirin remains the most commonly used antiplatelet agent among patients with atherosclerotic cardiovascular disease. Aspirin hypersensitivity occurs in 1% to 5% of patients and is among the most frequent causes for prohibiting the use of aspirin, posing a significant dilemma on how to manage these patients in clinical practice. Aspirin hypersensitivity is often misinterpreted and confused with aspirin intolerance, with treatment approaches being often unclear and lacking specific recommendations. Aspirin desensitization and low-dose aspirin challenge have emerged as pragmatic, effective, and safe approaches in patients with suspected or confirmed aspirin hypersensitivity who require aspirin therapy, but they are underused systematically in clinical practice. Furthermore, there is confusion over alternative antiplatelet agents to be used in these patients. The pathophysiological mechanisms and classification of aspirin hypersensitivity, as well as alternative strategies and practical algorithms to overcome the need for aspirin use in patients with atherosclerotic cardiovascular disease with suspected aspirin hypersensitivity, are discussed.

Management of Aspirin-Exacerbated Respiratory Disease: What Does the Future Hold?

Aspirin-exacerbated respiratory disease (AERD) is a subtype of chronic rhinosinusitis with polyps (CRSwNP) and asthma with higher recurrence of nasal polyps after surgery and severe asthma. Patients with CRSwNP and asthma should be screened for AERD by detailed history of aspirin/nonsteroidal anti-inflammatory drug reactions and review of medications that may mask aspirin reaction or directly by aspirin challenge. Treatment of AERD may require more intensive therapy, including endoscopic sinus surgery, daily aspirin therapy, leukotriene modifiers, or biologics.

Mast Cells in Aspirin-Exacerbated Respiratory Disease

PURPOSE OF REVIEW

Aspirin-exacerbated respiratory disease (AERD) is a syndrome of high type 2 inflammation and is known to critically involve mast cell activation. The mast cell is an important cell in the baseline inflammatory processes in the upper and lower airway by maintaining and amplifying type 2 inflammation. But it also is prominent in the hypersensitivity reaction to COX-1 inhibition which defines this condition.

RECENT FINDINGS

Recent work highlights the mast cell as a focal point in AERD pathogenesis. Using AERD as a specific model of both high type 2 asthma and chronic sinusitis, the role of mast cell activity can be better understood in other aspects of airway inflammation. Further dissecting out the mechanism of COX-1-mediated mast cell activation in AERD will be an important next phase in our understanding of NSAID-induced hypersensitivity as well as AERD pathophysiology.

Hypersensitivity to intravenous succinate corticosteroids in patients with nonsteroidal anti-inflammatory drug-exacerbated respiratory disease

Although there are many case reports of asthma exacerbations with intravenous corticosteroids, especially hydrocortisone succinate, in nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD), the frequency and mechanism remain unclear. We hypothesized that N-ERD patients are potentially hypersensitive to succinates, especially succinate corticosteroids, based on the results of previous provocation studies and considered specific mechanisms. The objective of this study was to determine the frequency and mechanism of succinate corticosteroids hypersensitivity in patients with N-ERD. Eleven patients with stable, moderate to severe N-ERD were tested with hydrocortisone sodium succinate (HCs), hydrocortisone sodium phosphate (HCp), methylprednisolone sodium succinate (MPSLs), prednisolone sodium succinate (PSLs), and chloramphenicol sodium succinate (CPs, without a steroidal chemical structure) at doses below the normal dose through intravenous administration using a single-blind test. As a comparison, seven patients with aspirin-tolerant asthma (ATA) also underwent an intravenous provocation test of HCs. The positive intravenous provocation test rates of HCs 100-500 mg, HCp 500 mg, MPSLs 80 mg, PSLs 20 mg, and CPs 500 mg in N-ERD patients were 82% (9/11), 9% (1/11), 50% (5/10), 33% (1/3), and 86% (6/7), respectively. Most positive reactions began with a severe cough within 5 min of intravenous injection. The course of these hypersensitivity symptoms differed from those seen with the usual aspirin challenge test. The HCs 100-500 mg intravenous test was negative in all seven patients with ATA. In conclusion, patients with N-ERD have high rates of potential hypersensitivity to the succinate ester structure, which is not linked to the corticosteroid structure, but to the succinate ester structure. We hypothesized that the mechanism of hypersensitivity observed during rapid intravenous administration of succinate corticosteroids is mast cell activation via succinate receptor stimulation, rather than due to the corticosteroid itself.

Dupilumab increases aspirin tolerance in NSAID-exacerbated respiratory disease

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (N-ERD) comprises the triad of chronic rhinosinusitis with nasal polyps, asthma and intolerance to NSAIDs. Dupilumab treatment, targeting the interleukin-4 (IL-4) receptor α, significantly reduces polyp burden as well as asthma symptoms. Here we aimed to investigate the effect of dupilumab on aspirin intolerance, burden of disease and nasal cytokine profiles in patients with N-ERD.

METHODS

In this open-label trial, adult patients with confirmed N-ERD were treated with dupilumab for 6 months. Clinical parameters (e.g. total polyp scores, quality of life questionnaires, smell test, spirometry), oral aspirin provocation testing and blood, nasal and urine sampling were monitored at regular intervals for up to 6 months after starting dupilumab therapy.

RESULTS

Of the 31 patients included in the study, 30 completed both aspirin provocation tests. After 6 months of treatment with dupilumab, 23% of patients (n=7 of 30) developed complete aspirin tolerance and an additional 33% of patients (n=10 of 30) tolerated higher doses. Polyp burden was significantly reduced (total polyp score: -2.68±1.84, p<0.001), while pulmonary symptoms (asthma control test: +2.34±3.67, p<0.001) and olfactory performance improved (University of Pennsylvania Smell Identification Test: +11.16±9.54, p<0.001) in all patients after therapy. Patients with increased aspirin tolerance showed a significant decrease in urinary leukotriene E4 levels and their improvement in clinical parameters was associated with a reduction of eotaxin-1, C-C motif chemokine ligand 17, IL-5, IL-17A and IL-6.

CONCLUSION

In this study, 57% of N-ERD patients tolerated higher doses of aspirin under dupilumab therapy.

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?

Updates on treatment options in aspirin exacerbated respiratory disease

PURPOSE OF REVIEW

The aim is to describe why this review is timely and relevant. Acetylsalicylic acid exacerbated respiratory disease (AERD) is a clinically significant disease affecting approximately 7% of all asthmatics or around 1,400,000 persons in the United States alone. A large portion of these patients remain undiagnosed. This review summarizes up to date knowledge on the pathophysiology, treatment opinions and provides an expert opinion on how to approach the AERD patient.

RECENT FINDINGS

Findings describe the main themes in the literature covered by the article. Review of the current knowledge in terms of the key cells, cytokines/chemokines contributing to the acquired disease state of AERD. It also provides clinical approach toward the AERD patient with regards to current treatment options.

SUMMARY

Summary describes the implications of the findings for clinical practice or research. This is an up-to-date review of the current literature, with insight into how to approach the management of an AERD patient.

Mediator production and severity of aspirin-induced respiratory reactions: Impact of sampling site and body mass index

BACKGROUND

Patients with aspirin-exacerbated respiratory disease can experience severe reactions during aspirin challenge that are associated with high levels of mast cell mediators. The tissue source and clinical factors contributing to systemic mediator levels are unknown.

OBJECTIVE

To determine the concordance between respiratory tract and systemic inflammatory mediator levels and identify clinical factors associated with these mediators.

METHODS

We performed an oral aspirin challenge in 30 subjects with aspirin-exacerbated respiratory disease. Respiratory symptoms and function, nasal mucosal fluid, blood, and urine were collected at baseline, at the onset of a respiratory reaction and over a 3-hour observation period. Changes in nasal and systemic mediator levels were compared.

RESULTS

Neither tryptase nor leukotriene E₄ levels in nasal fluid correlated with serum tryptase or urinary leukotriene E₄ at baseline or during reactions. We observed no association between the baseline or aspirin-induced change in nasal versus urinary leukotriene E₄ and serum tryptase levels. Body mass index inversely correlated with baseline and aspirin-induced urinary leukotriene E₄, prostaglandin D₂ metabolite, and serum tryptase levels, as well as with aspirin-induced symptoms and respiratory function, but not with nasal mediators.

CONCLUSION

The levels of nasal and systemic aspirin-induced mast cell products are discordant in aspirin-exacerbated respiratory disease. Systemically detected levels are likely derived from mast cells outside of the sinonasal cavity and do not accurately reflect upper respiratory tract production. Increased body mass index decreases systemic mast cell mediator production and reaction severity, supporting a contribution of metabolic regulation in aspirin-induced systemic reactions.

Biomarkers for predicting response to aspirin therapy in aspirin-exacerbated respiratory disease

Background

Aspirin desensitization followed by daily aspirin use is an effective treatment for aspirin‐exacerbated respiratory disease (AERD).

Objective

To assess clinical features as well as genetic, immune, cytological and biochemical biomarkers that might predict a positive response to high‐dose aspirin therapy in AERD.

Methods

We enrolled 34 AERD patients with severe asthma who underwent aspirin desensitization followed by 52‐week aspirin treatment (650 mg/d). At baseline and at 52 weeks, clinical assessment was performed; phenotypes based on induced sputum cells were identified; eicosanoid, cytokine and chemokine levels in induced sputum supernatant were determined; and induced sputum expression of 94 genes was assessed. Responders to high‐dose aspirin were defined as patients with improvement in 5‐item Asthma Control Questionnaire score, 22‐item Sino‐Nasal Outcome Test (SNOT‐22) score and forced expiratory volume in 1 second at 52 weeks.

Results

There were 28 responders (82%). Positive baseline predictors of response included female sex (p = .002), higher SNOT‐22 score (p = .03), higher blood eosinophil count (p = .01), lower neutrophil percentage in induced sputum (p = .003), higher expression of the hydroxyprostaglandin dehydrogenase gene, HPGD (p = .004) and lower expression of the proteoglycan 2 gene, PRG2 (p = .01). The best prediction model included Asthma Control Test and SNOT‐22 scores, blood eosinophils and total serum immunoglobulin E. Responders showed a marked decrease in sputum eosinophils but no changes in eicosanoid levels.

Conclusions and Clinical Relevance

Female sex, high blood eosinophil count, low sputum neutrophil percentage, severe nasal symptoms, high HPGD expression and low PRG2 expression may predict a positive response to long‐term high‐dose aspirin therapy in patients with AERD.

Mechanisms of Drug Desensitization: Not Only Mast Cells

Drug desensitization (DD) allows transient clinical tolerance to the drug in reactive patients and it is frequently and successfully used in the management of both IgE and non IgE-mediated hypersensitivity reactions (HRs). The underlying mechanisms behind this process is not well understood. The desensitization procedure is associated with the inhibition of mast cells degranulation and cytokine production, that, is attributable, at least partially, to the abrogation of Ca2+ mobilization; in vitro findings and in vivo mouse models of rapid desensitization show that the organization and spatial distribution of actin is critical for Ca2+ mobilization. Some clinical observations may suggest the induction of a longer memory of tolerance by DD and they raise the suspicion that other cells and mechanisms are involved in DD. Some data are emerging about the modifications of immune responses during DD in patients with previous immediate HRs. In particular, an increase of regulatory cytokines, mainly represented by IL-10, has been shown, and more importantly, the appearance of IL-35 producing T regulatory cells has been described during DD. The release of controlled cellular mediators by mast cells over time and the development of the antigen-specific regulation of adaptive response allow to safely and successfully reach the target dose of a first line drug during DD.

Adult-onset eosinophilic airway diseases

Eosinophilic airway inflammation is one of the cardinal features of allergic airway diseases such as atopic asthma and allergic rhinitis. These childhood-onset conditions are mediated by allergen and allergen-specific IgE and often accompanied by other allergic diseases including food allergy and eczema. They can develop consecutively in the same patient, which is referred to as an allergic march. In contrast, some phenotypes of asthma, nonsteroidal anti-inflammatory drugs-exacerbated airway disease (N-ERD), chronic rhinosinusitis with nasal polyps (CRSwNP)/eosinophilic CRS and allergic bronchopulmonary aspergillosis/mycosis (ABPA/ABPM) are adult-onset airway diseases, which are characterized by prominent peripheral blood eosinophilia. Most of these conditions, except for ABPA/ABPM, are nonatopic, and the coexistence of multiple diseases, including an adult-onset eosinophilic systemic disease, eosinophilic granulomatosis with polyangiitis (EGPA), is common. In this review, we focus on eosinophil biology, genetics and clinical characteristics and the pathophysiology of adult-onset eosinophilic asthma, N-ERD, CRSwNP/eosinophilic CRS, ABPA/ABPM and EGPA, while exploring the common genetic, immunological and pathological conditions among these adult-onset eosinophilic diseases.

Systematic review of outcomes for endoscopic sinus surgery and subsequent aspirin desensitization in aspirin-exacerbated respiratory disease

Objective

To review and evaluate outcomes of patients with aspirin-exacerbated respiratory disease (AERD) following endoscopic sinus surgery and subsequent aspirin desensitization.

Methods

Electronic searches of OVID MEDLINE (1948 to September 10, 2019), EMBASE (1980 to September 10, 2019), and PubMed were performed on September 10, 2019. A systematic review of the literature was performed using the 2009 PRISMA guidelines. Studies with both preoperative and postoperative data for patients with AERD who underwent sinus surgery and aspirin desensitization were considered appropriate for inclusion. Publications were written in English and included patients aged 18 years or older.

Results

Six studies met inclusion criteria for this systematic review. The primary outcome measure was change in symptom profile measured by patient-reported quality of life scores. The results demonstrate statistically significant improvement in symptoms following endoscopic sinus surgery, with sustained improvement following aspirin desensitization. Revision surgery rates were significantly lower in patients maintained on aspirin therapy.

Conclusion

This review suggests that surgery followed by aspirin desensitization results in improvement in both subjective and objective outcome measures. The adjunctive use of aspirin desensitization allows for long-term stability in symptom scores. Recurrence of polyps and worsening symptoms requiring revision surgery occurs when aspirin maintenance therapy is interrupted.

Effects of Omalizumab Treatment in Patients With Recalcitrant Nasal Polyposis and Mild Asthma: A Multicenter Retrospective Study

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a clinical entity with specific features that impacts significantly on patient quality of life (QoL). CRSwNP is often associated with asthma and is difficult to control and manage despite pharmacological and/or surgical treatment. Omalizumab, a monoclonal anti-IgE antibody, has emerged as a putative therapeutic option.

OBJECTIVE

To evaluate the effects of omalizumab on nasal polyp (NP) size and QoL assessed by Sino-Nasal Outcome Test-22 (SNOT-22) in patients with recalcitrant CRSwNP and mild asthma.

METHODS

A multicenter retrospective analysis of patient data from the Community of Valencia (Spain) was performed. Adult patients with recalcitrant CRSwNP and comorbid mild asthma receiving compassionate use of omalizumab were included. NP size measured by total nasal endoscopic polyp score (TPS) and QoL evaluated through the SNOT-22 questionnaire were assessed at baseline and monthly over 12 months. An ordinal regression model was built to analyze the results.

RESULTS

A total of 23 CRSwNP patients with a mean age (± SD) of 54.78 ± 9.46 years were included. Nineteen suffered from aspirin-exacerbated respiratory disease (AERD). In all patients, a significant and sustained reduction in TPS was observed over time, accompanied by improvements in QoL reflected in lower SNOT-22 scores. In the ordinal regression model, time but not total IgE, age or tissue eosinophilia impacted on NP size and SNOT-22 outcomes. Additionally, improvements in QoL were not explained by reductions in the size of polyps.

CONCLUSION

Omalizumab was effective for the treatment of patients with recalcitrant CRSwNP and mild asthma, even when AERD was present, by reducing NP size and improving QoL; treatment time was a key factor. SNOT-22 improvements were not explained by decreases in TPS, indicating that omalizumab may be effective in all patients, regardless of polyp size.

Immune-Related Adverse Drug Reactions and Immunologically Mediated Drug Hypersensitivity

Biologic and other therapies used for the treatment of immune-mediated hypersensitivity conditions, and in people with immune-mediated hypersensitivity, can trigger a wide variety of immune-related adverse drug reactions and immunologically mediated drug hypersensitivities. These range from acute-onset immunoglobulin E-mediated allergies to delayed-onset T-cell-mediated hypersensitivities. Certain therapeutic and diagnostic agents can directly activate mast cells. Biologic agents used to treat immune-mediated hypersensitivity can also globally upregulate or downregulate the immune system leading to pathologic reactions, including cytokine storm and hypogammaglobulinemia.

Omalizumab for Aspirin Hypersensitivity and Leukotriene Overproduction in Aspirin-exacerbated Respiratory Disease. A Randomized Controlled Trial

Rationale: Aspirin-exacerbated respiratory disease is characterized by severe asthma, nonsteroidal antiinflammatory drug hypersensitivity, nasal polyposis, and leukotriene overproduction. Systemic corticosteroid therapy does not completely suppress lifelong aspirin hypersensitivity. Omalizumab efficacy against aspirin-exacerbated respiratory disease has not been investigated in a randomized manner.

Objectives: To evaluate omalizumab efficacy against aspirin hypersensitivity, leukotriene E₄ overproduction, and symptoms during an oral aspirin challenge in patients with aspirin-exacerbated respiratory disease using a randomized design.

Methods: We performed a double-blind, randomized, crossover, placebo-controlled, single-center study at Sagamihara National Hospital between August 2015 and December 2016. Atopic patients (20–79 yr old) with aspirin-exacerbated respiratory disease diagnosed by systemic aspirin challenge were randomized (1:1) to a 3-month treatment with omalizumab or placebo, followed by a >18-week washout period (crossover design). The primary endpoint was the difference in area under logarithm level of urinary leukotriene E₄ concentration versus time curve in the intent-to-treat population during an oral aspirin challenge.

Measurements and Main Results: Sixteen patients completed the study and were included in the analysis. The area under the logarithm level of urinary leukotriene E₄ concentration versus time curve during an oral aspirin challenge was significantly lower in the omalizumab phase (median [interquartile range], 51.1 [44.5–59.8]) than in the placebo phase (80.8 [interquartile range, 65.4–87.8]) (P < 0.001). Ten of 16 patients (62.5%) developed oral aspirin tolerance up to cumulative doses of 930 mg in the omalizumab phase (P < 0.001).

Conclusions: Omalizumab treatment inhibited urinary leukotriene E₄ overproduction and upper/lower respiratory tract symptoms during an oral aspirin challenge, resulting in aspirin tolerance in 62.5% of the patients with aspirin-exacerbated respiratory disease.

Aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) classically presents with severe asthma, nasal polyposis, and respiratory exacerbations in response to cyclooxygenase (COX)-1 inhibition. Recent advances in our understanding of AERD have revealed multiple facets of immune dysregulation, including diminished prostaglandin E2 (PGE₂) function and elevated levels of both cysteinyl leukotrienes (CysLTs) and innate cytokines such as interleukin 33 (IL-33). Inflammatory mediators in AERD heighten the recruitment and activation of innate lymphoid cells type 2 (ILC2), mast cells, eosinophils, and platelet-adherent leukocytes. This contributes to a cyclical pattern of type 2 inflammation. Here, we highlight current understanding of the immunopathogenesis of AERD.