Diagnostic Utility of Urinary LTE4 in Asthma, Allergic Rhinitis, Chronic Rhinosinusitis, Nasal Polyps, and Aspirin Sensitivity

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.

Pharmacometabolomics of Asthma as a Road Map to Precision Medicine

Pharmacometabolomics applies the principles of metabolomics to therapeutics in order to elucidate the biological mechanisms underlying the variation in responses to drugs between groups and individuals. Asthma is associated with broad systemic effects and heterogeneity in treatment response and as such is ideally suited to pharmacometabolomics. In this chapter, we discuss the state of the emerging field of asthma pharmacometabolomics, with a particular focus on studies of steroids, bronchodilators, and leukotriene inhibitors. We also consider those studies concerned with subtyping cases to better understand the pharmacology of those groups and those looking to leverage pharmacometabolomics for asthma prevention. We finish with a discussion of the challenges and opportunities of asthma pharmacometabolomics and reflect upon where this field must go next in order to realize its precision medicine potential.

Levels of eicosanoids in nasal secretions associated with nasal polyp severity in chronic rhinosinusitis

Severe nasal polyposis and mucosal inflammation, in patients with chronic rhinosinusitis (CRS) may include a dysregulated eicosanoid profile, but a clinical role for eicosanoids in CRS with nasal polyps (NP; CRSwNP) remains to be elucidated. This study focused on assessing levels and clinical implications of inflammatory mediators in nasal secretions and urine from patients with different NP severity or Aspirin Exacerbated Respiratory Disease (AERD). Levels of leukotrienes E₄ and B₄, prostaglandins D₂ and E₂ as well as 15(S)-hydroxyeicosatetraenoic acid were measured with enzyme immunoassays and cytokines with magnetic bead immunoassays. Patients with CRSwNP were subdivided based on NP score; CRSwNP-low (NP score ≤ 4, n = 11) or CRSwNP-high (NP score ≥ 5, n = 32) and compared to CRS without polyps (CRSsNP, n = 12), CRSwNP-AERD (n = 11) and individuals without CRS (n = 25). Smell test score, fractional exhaled nitric oxide (FeNO), blood eosinophils and Sinonasal outcome test-22 were assessed as clinical markers. Leukotriene E₄, prostaglandin D₂ and 15(S)-hydroxyeicosatetraenoic acid in nasal secretions correlated with NP score. Nasal leukotriene E₄ also correlated with FeNO and smell test score, with highest levels found in CRSwNP-AERD. Levels of prostaglandin D₂ in nasal secretion as well as urinary levels of the prostaglandin D₂ metabolite 11β-prostaglandin F_2α differed between CRSNP-high and CRSwNP-low. Urinary 11β-prostaglandin F_2α was associated with asthma comorbidity whereas a similar association with prostaglandin D₂ in nasal secretions was not observed. In conclusion, subdividing patients based on NP severity in combination with analysis of eicosanoids in non-invasively collected nasal secretions, may have clinical implications when assessing CRS disease severity.

Emerging Biomarkers Beyond Leukotrienes for the Management of Nonsteroidal Anti-inflammatory Drug (NSAID)-Exacerbated Respiratory Disease

Nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD) is a unique condition characterized by aspirin/NSAID hypersensitivity, adult-onset asthma, and/or chronic rhinosinusitis with nasal polyps. Arachidonic acid metabolism dysregulation and intense eosinophilic/type 2 inflammation are central mechanisms in NERD. Studies have been conducted on various biomarkers, and urinary leukotriene E4 is considered the most available biomarker of NERD. However, the pathophysiology of NERD is heterogeneous and complex. Epithelial cells and platelets can interact with immune cells in NERD, and novel biomarkers related to these interactions have recently been investigated. We summarize emerging novel biomarkers of NERD and discuss their roles in the management of NERD.

Urine Leukotriene E4: Implications as a Biomarker in Chronic Rhinosinusitis

OBJECTIVE

To provide a comprehensive state-of-the-art review of the emerging role of urine leukotriene E4 (uLTE4) as a biomarker in the diagnosis of chronic rhinosinusitis (CRS), aspirin-exacerbated respiratory disease (AERD), and asthma.

DATA SOURCES

Ovid MEDLINE(R), Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus.

REVIEW METHODS

A state-of-the-art review was performed investigating the role of uLTE4 as a diagnostic biomarker, predictor of disease severity, and potential marker of selected therapeutic efficacy.

CONCLUSIONS

uLTE4 has been shown to be a reliable and clinically relevant biomarker for CRS, AERD, and asthma. uLTE4 is helpful in ongoing efforts to better endotype patients with CRS and to predict disease severity.

IMPLICATIONS FOR PRACTICE

Aside from being a diagnostic biomarker, uLTE4 is also able to differentiate aspirin-tolerant patients from patients with AERD and has been associated with objective disease severity in patients with CRS with nasal polyposis. uLTE4 levels have also been shown to predict response to medical therapy, particularly leukotriene-modifying agents.

Noninvasive and minimally invasive techniques for the diagnosis and management of allergic diseases

Allergic diseases of the (upper and lower) airways, the skin and the gastrointestinal tract, are on the rise, resulting in impaired quality of life, decreased productivity, and increased healthcare costs. As allergic diseases are mostly tissue-specific, local sampling methods for respective biomarkers offer the potential for increased sensitivity and specificity. Additionally, local sampling using noninvasive or minimally invasive methods can be cost-effective and well tolerated, which may even be suitable for primary or home care sampling. Non- or minimally invasive local sampling and diagnostics may enable a more thorough endotyping, may help to avoid under- or overdiagnosis, and may provide the possibility to approach precision prevention, due to early diagnosis of these local diseases even before they get systemically manifested and detectable. At the same time, dried blood samples may help to facilitate minimal-invasive primary or home care sampling for classical systemic diagnostic approaches. This EAACI position paper contains a thorough review of the various technologies in allergy diagnosis available on the market, which analytes or biomarkers are employed, and which samples or matrices can be used. Based on this assessment, EAACI position is to drive these developments to efficiently identify allergy and possibly later also viral epidemics and take advantage of comprehensive knowledge to initiate preventions and treatments.

Urinary leukotrienes and histamine in patients with varying severity of acute dengue

Background

Vascular leak is a hallmark of severe dengue, and high leukotriene levels have been observed in dengue mouse models, suggesting a role in disease pathogenesis. We sought to explore their role in acute dengue, by assessing levels of urinary LTE4 and urinary histamine in patients with varying severity of acute dengue.

Methods

Urinary LTE4_, histamine and creatinine were measured by a quantitative ELISA, in healthy individuals (n = 19), patients with dengue fever (DF = 72) and dengue haemorrhagic fever DHF (n = 48). The kinetics of LTE4 and histamine and diurnal variations were assessed in a subset of patients.

Results

Urinary LTE4 levels were significantly higher (p = 0.004) in patients who proceed to develop DHF when compared to patients with DF during early illness (≤ 4 days) and during the critical phase (p = 0.02), which continued to rise in patients who developed DHF during the course of illness. However, LTE4 is unlikely to be a good biomarker as ROCs gave an AUC value of 0.67 (95% CI 0.57 and 0.76), which was nevertheless significant (p = 0.002). Urinary LTE4 levels did not associate with the degree of viraemia, infecting virus serotype and was not different in those with primary vs secondary dengue. Urinary histamine levels were significantly high in patients with acute dengue although no difference was observed between patients with DF and DHF and again did not associate with the viraemia. Interestingly, LTE4, histamine and the viral loads showed a marked diurnal variation in both patients with DF and DHF.

Conclusions

Our data suggest that LTE4 could play a role in disease pathogenesis and since there are safe and effective cysteinyl leukotriene receptor blockers, it would be important to assess their efficacy in reducing dengue disease severity.

Elevated Urine Leukotriene E4 Is Associated With Worse Objective Markers in Nasal Polyposis Patients

OBJECTIVES

Urine leukotriene E4 (uLTE4) is a biomarker of leukotriene synthesis and is elevated in patients with aspirin-exacerbated respiratory disease (AERD). It can also be useful to help delineate aspirin-tolerant chronic rhinosinusitis with nasal polyposis (CRSwNP) patients from AERD patients. The purpose of this study is to determine if uLTE4 biomarker levels are associated with objective and subjective markers of disease severity in patients with CRSwNP.

METHODS

A retrospective analysis of CRSwNP patients who underwent uLTE4 testing was completed to determine the association of uLTE4 levels to markers of disease severity. uLTE4 levels, as well as presenting subjective (Sinonasal Outcome Test 22 [SNOT22] scores, asthma control test [ACT] scores) and objective data (Lund-Mackay CT score, spirometry and lab values) were collected.

RESULTS

Among the 157 CRSwNP patients who met inclusion criteria, uLTE4 levels were associated with history of asthma (P < .001), aspirin sensitivity (P < .001), worse Lund-Mackay CT scores (P = .002) and other objective markers of disease severity including serum IgE (P = .05), presenting blood eosinophil level (P < .001), and the highest recorded eosinophil level (P < .001). In subgroup analysis, associations of uLTE4 to disease markers had stronger correlations in the aspirin sensitive CRSwNP group (R range 0.31-0.52) than the aspirin tolerant CRSwNP group (R range -0.30-0.24). uLTE4 levels were not associated with subjective symptom scores (SNOT22 and ACT scores).

CONCLUSION

Elevated uLTE4 biomarker levels are associated with worsened objective markers of disease severity in CRSwNP patients but not patient-reported symptom measures.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:961-966, 2021.

Artificial neural network identifies nonsteroidal anti-inflammatory drugs exacerbated respiratory disease (N-ERD) cohort

Background

To date, there has been no reliable in vitro test to either diagnose or differentiate nonsteroidal anti‐inflammatory drug (NSAID)–exacerbated respiratory disease (N‐ERD). The aim of the present study was to develop and validate an artificial neural network (ANN) for the prediction of N‐ERD in patients with asthma.

Methods

This study used a prospective database of patients with N‐ERD (n = 121) and aspirin‐tolerant (n = 82) who underwent aspirin challenge from May 2014 to May 2018. Eighteen parameters, including clinical characteristics, inflammatory phenotypes based on sputum cells, as well as eicosanoid levels in induced sputum supernatant (ISS) and urine were extracted for the ANN.

Results

The validation sensitivity of ANN was 94.12% (80.32%‐99.28%), specificity was 73.08% (52.21%‐88.43%), and accuracy was 85.00% (77.43%‐92.90%) for the prediction of N‐ERD. The area under the receiver operating curve was 0.83 (0.71‐0.90).

Conclusions

The designed ANN model seems to have powerful prediction capabilities to provide diagnosis of N‐ERD. Although it cannot replace the gold‐standard aspirin challenge test, the implementation of the ANN might provide an added value for identification of patients with N‐ERD. External validation in a large cohort is needed to confirm our results.

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.

NSAID-ERD Syndrome: the New Hope from Prevention, Early Diagnosis, and New Therapeutic Targets

PURPOSE OF REVIEW

This review summarizes the latest information on the appropriate identification, evaluation, and treatment of patients with nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NSAID-ERD), also known as aspirin-exacerbated respiratory disease (AERD). Within the framework of our understanding of the underlying pathophysiology of NSAID-ERD, we also provide an update regarding new surgical techniques and newly available or upcoming medical therapies that may benefit these patients.

RECENT FINDINGS

There have been considerable developments regarding recommendations for both the extent and timing of sinus surgery for NSAID-ERD. The last few years have also given us several new biologic medications that warrant consideration in the treatment of patients with recalcitrant NSAID-ERD. Further clinical trials are underway to investigate additional medications that may decrease the type 2 inflammation that dominates this disease. Despite the severe lower respiratory inflammation and recurrent nature of the nasal polyps in patients with NSAID-ERD, significant recent advances now afford much-improved quality of life for these patients. Careful collaboration between Allergy/Immunology and Rhinology specialists is imperative to ensure proper treatment of patients with NSAID-ERD.

Chronic rhinosinusitis with nasal polyposis: the role of personalized and integrated medicine

Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a frequent disorder. From a clinical and an immunopathological point of view, different phenotypes and endotypes have been identified. The frequent comorbidity with asthma allowed to pave the way to the use of biological agents for the treatment of CRSwNP. Biological agents are targeted to antagonize IgE, interleukin (IL) 4, IL-5, and IL-13 at present. However, a correct and appropriate workup is mandatory, mainly concerning the exact definition of the specific pheno-endotype. The preliminary outcomes are promising, even though there is a need for well-established indications, criteria of responsiveness, duration, and safety. On the other hand, this personalized medicine could be fruitfully integrated with gold-standard medications, such as intranasal corticosteroids. As CRSwNP is a chronic disorder, treatment should be long-lasting, so complementary anti-inflammatory treatments could be opportunely integrated and/or alternated to steroids. (www.actabiomedica.it)

Update on the Management of Nonsteroidal Anti-Inflammatory Drug Hypersensitivity

The clinical phenotypes of nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity are heterogeneous with various presentations including time of symptom onset, organ involvements, and underlying pathophysiology. Having a correct diagnosis can be challenging. Understanding their respective mechanisms as well as developing a comprehensive classification and diagnostic algorithm are pivotal for appropriate management strategy. Treatment modalities are based on the subtypes and severity of hypersensitivity reactions. Insights into the phenotypes and endotypes of hypersensitivity reactions enable personalized management in patients with suboptimal control of disease. This review updated the recent evidence of pathophysiology, classification, diagnostic algorithm, and management of NSAID hypersensitivity reactions.

Eosinophilic Asthma

Asthma endotypes are constantly evolving. Currently, there are no universally accepted criteria to define endotypes. The T_H2-high endotype can have either allergic or nonallergic underpinnings and is typically characterized by some degree of eosinophilic airway inflammation. Unbiased clustering analyses have led to the identification of pediatric and adult phenotypes characterized by T_H2 inflammation and associated endotypes with eosinophilic inflammation. Aspirin-exacerbated respiratory disease has also long been recognized as a unique asthma phenotype. An approach to identify these groups with biomarkers and subsequently choose a targeted therapeutic modality, particularly in severe disease requiring biologic agents, is outlined.

Establishing Urinary Leukotriene E4 as a Diagnostic Biomarker for Chronic Rhinosinusitis with Comorbid Asthma and Atopy

OBJECTIVE

While urinary leukotriene E₄ (uLTE₄) is a validated biomarker for the cysteinyl leukotriene pathway, which is central to the pathophysiology of asthma, atopy, and chronic rhinosinusitis (CRS), the contributions of comorbid asthma and atopy to uLTE₄ levels in various CRS subtypes have not been previously characterized. We sought to (1) identify reference values for uLTE₄ in subjects with and without CRS and (2) determine how the presence of comorbid atopy and asthma affects uLTE₄ levels in CRS.

SETTING

Tertiary referral medical center.

SUBJECTS AND METHODS

A prospective case-control study was conducted to compare uLTE₄ levels between patients with CRS and healthy controls. Urinary LTE₄ levels were measured by enzyme immunoassay and were adjusted for urinary creatinine concentrations (pg/mg Cr). Patients with CRS were stratified by the clinical comorbidities to determine normative uLTE₄ values for patients with CRS with and without comorbid asthma or atopy.

RESULTS

A total of 153 patients (mean age, 47.3; 47.1% female) were included in the study. Patients with CRS demonstrated significantly higher concentrations of uLTE₄ than healthy controls (1652 vs 1065 pg/mg Cr, P = .032). Within the group of patients with CRS, comorbid asthma also individually correlated with elevated uLTE₄ levels (1597 pg/mg Cr, P = .0098). Patients with CRS who did not have comorbid allergy and asthma, in contrast, did not have statistically higher uLTE₄ levels than healthy controls (1142 pg/mg Cr, P = .61).

CONCLUSION

Urinary LTE₄ serves as a noninvasive measure of the inflammatory state in CRS. Comorbid asthma and atopy contribute to elevated uLTE₄ levels in CRS.

Understanding Asthma Phenotypes, Endotypes, and Mechanisms of Disease

The model of asthma as a single entity has now been replaced by a much more complex biological network of distinct and interrelating inflammatory pathways. The term asthma is now considered an umbrella diagnosis for several diseases with distinct mechanistic pathways (endotypes) and variable clinical presentations (phenotypes). The precise definition of these endotypes is central to asthma management due to inherent therapeutic and prognostic implications. This review presents the molecular mechanisms behind the heterogeneity of airway inflammation in asthmatic patients. Asthma endotypes may be broadly regarded as type 2 (T2) high or T2-low. Several biologic agents have been approved for T2-high asthma, with numerous other therapeutics that are incipient and similarly targeted at specific molecular mechanisms. Collectively, these advances have shifted existing paradigms in the approach to asthma to tailor novel therapies.

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.

Prostaglandin E2 decrease in induced sputum of hypersensitive asthmatics during oral challenge with aspirin

BACKGROUND

A special regulatory role for prostaglandin E₂ (PGE₂ ) has been postulated in nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD).

OBJECTIVE

To investigate the effect of systemic aspirin (acetylsalicylic acid) administration on airway PGE₂ biosynthesis in induced sputum supernatant (ISS) among subjects with NERD or aspirin-tolerant asthma with chronic rhinosinusitis with nasal polyposis (ATA-CRSwNP), as well as healthy controls (HC).

METHODS

Induced sputum (IS) was collected from patients with NERD (n = 26), ATA-CRSwNP (n = 17), and HC (n = 21) at baseline and after aspirin challenge. Sputum differential cell count and IS supernatant (ISS) levels of prostanoids, PGE₂ , 8-iso-PGE₂ , tetranor-PGE-M, 8-iso-PGF₂ α, and leukotriene C₄ , D₄ , and E₄ , were determined using mass spectrometry. Urinary excretion of LTE₄ was measured by ELISA.

RESULTS

NERD subjects had elevated sputum eosinophilic count as compared to ATA-CRSwNP and HC (median NERD 9.1%, ATA-CRSwNP 2.1%, and HC 0.4%; P < 0.01). Baseline ISS levels of PGE₂ were higher in asthmatics as compared to HC at baseline (NERD vs HC P = 0.04, ATA-CRSwNP vs HC P < 0.05). Post-challenge ISS levels of PGE₂ compared to baseline significantly decreased in NERD and HC (P < 0.01 and P = 0.01), but not in ATA-CRSwNP. In NERD, a similar decrease in PGE₂ as in HC resulted from 2.8 times lower dose of aspirin.

CONCLUSION

Aspirin-precipitated bronchoconstriction is associated with a decrease in airway PGE₂ biosynthesis. These results support the mechanism of PGE₂ biosynthesis inhibition as a trigger for bronchoconstriction in NERD.

Precision Medicine in Rhinosinusitis

PURPOSE OF REVIEW

Our scope is the presentation of research and clinical progresses in relation to precision medicine that are expected to alter our clinical practice in relation to chronic rhinosinusitis (CRS). Current knowledge on phenotypes and endotypes, biomarkers, and clinical markers for diagnosis, medical and surgical therapy, and prognosis is presented as well as the role of precision medicine in United Airway Disease and SCUAD (severe-uncontrolled chronic upper airway inflammation).

RECENT FINDINGS

Current technological progresses, mostly in relation to molecular biology and information technology, have permitted more detailed pathophysiological assessments and multidimensional approaches in airways diseases. Based on the concept of united airways diseases, new classification schemes, called endotypes, have been proposed for CRS. In addition, novel biological treatments that have been introduced for the treatment of asthma show great promise as well for severe uncontrolled cases of CRS with nasal polyps. Central to this approach are new biomarkers that are being examined in relation to complex bio-clinical traits of CRS. As this narrative review of the aforementioned precision medicine initiatives in relation to CRS advances, a modification of current practice is expected not only for severe chronic upper airways diseases in tertiary centers but also for milder and more common cases that are being encountered in the community.

Prostaglandin E2 in NSAID-exacerbated respiratory disease: protection against cysteinyl leukotrienes and group 2 innate lymphoid cells

PURPOSE OF REVIEW

The purpose of this review is to describe the recent advances that have been made in understanding the protective role of prostaglandin E2 (PGE2) in aspirin-exacerbated respiratory disease (AERD), known in Europe as NSAID-exacerbated respiratory disease (N-ERD).

RECENT FINDINGS

Decreased PGE2 signaling through the EP2 receptor in patients with AERD leads to an increase in leukotriene synthesis and signaling. Leukotriene signaling not only directly activates group 2 innate lymphoid cells and mast cells, but it also increases production of IL-33 and thymic stromal lymphopoietin. These cytokines drive Th2 inflammation in a suspected feed-forward mechanism in patients with AERD.

SUMMARY

Recent discoveries concerning the role of PGE2 in leukotriene synthesis and signaling in AERD, as well as downstream effects on group 2 innate lymphoid cells and mast cells, allow for a more comprehensive understanding of the pathogenesis of this disease. These discoveries also identify new paths of potential investigation and possible therapeutic targets for AERD.

Sinus Surgery Is Associated with a Decrease in Aspirin-Induced Reaction Severity in Patients with Aspirin Exacerbated Respiratory Disease

BACKGROUND

Nasal polyps influence the burden of aspirin-exacerbated respiratory disease (AERD) by contributing to eicosanoid production. AERD is diagnosed through graded aspirin challenges. It is not known how sinus surgery affects aspirin challenge outcomes.

OBJECTIVE

To investigate the effects of endoscopic sinus surgery (ESS) on aspirin-induced reaction severity and on the levels of eicosanoids associated with these reactions.

METHODS

Twenty-eight patients with AERD were challenged with aspirin before and 3 to 4 weeks after ESS. Respiratory parameters and plasma and urine levels of eicosanoids were compared before and after challenges.

RESULTS

Before ESS, AERD diagnosis was confirmed in all study patients by aspirin challenges that resulted in hypersensitivity reactions. After ESS, reactions to aspirin were less severe in all patients and 12 of 28 patients (43%, P < .001) had no detectable reaction. A lack of clinical reaction to aspirin was associated with lower peripheral blood eosinophilia (0.1 K/μL [interquartile range (IQR) 0.1-0.3] vs 0.4 K/μL [IQR 0.2-0.8]; P = .006), lower urinary leukotriene E₄ levels after aspirin challenge (98 pg/mg creatinine [IQR 61-239] vs 459 pg/mg creatinine [IQR 141-1344]; P = .02), and lower plasma prostaglandin D₂ to prostaglandin E₂ ratio (0 [±0] vs 0.43 [±0.2]; P = .03), compared with those who reacted.

CONCLUSIONS

Sinus surgery results in decreased aspirin sensitivity and a decrease in several plasma and urine eicosanoid levels in patients with AERD. Diagnostic aspirin challenges should be offered to patients with suspected AERD before ESS to increase diagnostic accuracy. Patients with established AERD could undergo aspirin desensitizations after ESS as the severity of their aspirin-induced hypersensitivity reactions lessens.

Urine concentrations changes of cysteinyl leukotrienes in non-obese children with obstructive sleep apnea undergoing adenotonsillectomy

OBJECTIVE

The main objective of the study was to compare preoperative to postoperative levels of urine-Cysteinyl leukotrienes (uCysLT) in children undergoing adenotonsillectomy (AT) for obstructive sleep apnea (OSA) in order to investigate whether exaggerated leukotriene activity is the cause or consequence of OSA.

METHODS AND MATERIALS

A prospective study was conducted on non-obese children (4-10 years old) referred for overnight PSG. Children with moderate/severe OSA treated with AT were included. A second PSG study performed 2 months postoperatively to confirm OSA resolution, and those with residual OSA were excluded. Morning urine specimens after both PSG studies were obtained and pre-operative uCysLT levels were compared to postoperative levels.

RESULTS

27 children fulfilled the criteria and underwent a post-operative PSG study with three exclusions for residual OSA (postop-AHI>2), so the study group consisted of 24 children (mean age: 5.7 ± 2.1 years). Mean preoperative and postoperative AHI was 10.96 ± 5.93 and 1.44 ± 0.56 respectively. Mean preop-uCysLT were 21.14 ± 4.65, while after AT they significantly reduced to 12.62 ± 2.67 (P < 0.01).

CONCLUSION

uCysLT levels are significantly reduced after AT in non-obese children with moderate/severe OSA, suggesting that exaggerated leukotriene activity is mainly a consequence of OSA.

Recent developments and highlights in biomarkers in allergic diseases and asthma

The potential of precision medicine in allergy and asthma has only started to be explored. A significant clarification in the pathophysiology of rhinitis, chronic rhinosinusitis, asthma, food allergy and drug hypersensitivity was made in the last decade. This improved understanding led to a better classification of the distinct phenotypes and to the discovery of new drugs such as biologicals, targeting phenotype-specific mechanisms. Nevertheless, many conditions remain poorly understood such as non-eosinophilic airway diseases or non-IgE-mediated food allergy. Moreover, there is a need to predict the response to specific therapies and the outcome of drug and food provocations. The identification of patients at risk of progression towards severity is also an unmet need in order to establish adequate preventive or therapeutic measures. The implementation of precision medicine in the clinical practice requires the identification of phenotype-specific markers measurable in biological matrices. To become useful, these biomarkers need to be quantifiable by reliable systems, and in samples obtained in an easy, rapid and cost-efficient way. In the last years, significant research resources have been put in the identification of valid biomarkers for asthma and allergic diseases. This review summarizes these recent advances with focus on the biomarkers with higher clinical applicability.

The utility of biomarkers in diagnosis of aspirin exacerbated respiratory disease

Background

Aspirin-exacerbated respiratory disease (AERD) is a distinct eosinophilic phenotype of severe asthma with accompanying chronic rhinosinusitis, nasal polyposis, and hypersensitivity to aspirin. Urinary 3-bromotyrosine (uBrTyr) is a noninvasive marker of eosinophil-catalyzed protein oxidation. The lack of in vitro diagnostic test makes the diagnosis of AERD difficult. We aimed to determine uBrTyr levels in patients with AERD (n = 240) and aspirin-tolerant asthma (ATA) (n = 226) and to assess whether its addition to urinary leukotriene E₄ (uLTE₄) levels and blood eosinophilia can improve the prediction of AERD diagnosis.

Methods

Clinical data, spirometry and blood eosinophilis were evaluated. UBrTyr and uLTE₄ levels were measured in urine by HPLC and ELISA, respectively.

Results

Both groups of asthmatics (AERD, n = 240; ATA, n = 226) had significantly higher uBrTyr, uLTE₄ levels, and blood eosinophils than healthy controls (HC) (n = 71) (p < 0.05). ULTE₄ levels and blood eosinophils were significantly higher in AERD as compared to ATA (p = 0.004, p < 0.0001, respectively). whereas uBrTyr levels were not significantly different between both asthma phenotypes (p = 0.34). Asthmatics with high levels of uBrTyr (> 0.101 ng/mg Cr), uLTE₄ levels (> 800 pg/mg Cr) and blood eosinophils (> 300 cells/ul) were 7 times more likely to have AERD.. However, uBrTyr did not increase the benefit for predicting AERD when uLTE₄ and blood eosinophils were already taken into account (p = 0.57).

Conclusion

UBrTyr levels are elevated both in AERD and ATA as compared to HC, but they could not differentiate between these asthma phenotypes suggesting a similar eosinophilic activation. The addition of uBrTyr to elevated uLTE4 levels and blood eosinophils did not statistically enhance the prediction of AERD diagnosis.

Urinary Leukotriene E4 as a Biomarker of Exposure, Susceptibility, and Risk in Asthma: An Update

Measurement of urinary leukotriene E₄ (uLTE₄) is a sensitive and noninvasive method of assaying total body cysteinyl leukotriene (CysLT) production and changes in CysLT production. Recent studies have reported on novel LTE4 receptor interactions and genetic polymorphisms causing CysLT variability. The applications of uLTE₄ as a biomarker continue to expand, including evaluation of environmental exposures, asthma severity risk, aspirin sensitivity, predicting atopy in preschool age children, obstructive sleep apnea, and predicting susceptibility to leukotriene receptor antagonists.

Towards precision medicine in severe asthma: Treatment algorithms based on treatable traits

Asthma is a common disease, and although its clinical manifestations may be similar among patients, recent research discoveries have shown that it consists of several distinct clinical clusters or phenotypes, each with different underlying molecular pathways yielding different treatment responses. Based on these observations, an alternative approach - known as 'precision medicine' - has been proposed for the management of patients with severe asthma. Precision medicine advocates identification of treatable traits, linking them to therapeutic approaches targeting genetic, immunological, environmental, and/or lifestyle factors in individual patients. The main "goal" of this personalised approach is to enable choosing a treatment which will be more likely to produce a beneficial response in the individual patient rather than a 'one size fits all' approach. The aim of the present review is to discuss different ways of phenotyping asthma and to provide a rationale for treatment algorithms based on principles of precision medicine.

Future Horizons in Allergy

There are several advances in diagnosis and management for the otolaryngologist treating allergy. These include new technologies and the refinement of current techniques, and reflect overall trends in health care toward personalized medicine. Local immunoglobulin, urinary leukotriene E4, lipidomics, microRNA within extracellular vesicles, and optical rhinometry all offer to improve the diagnostic accuracy of allergy and related nonallergic conditions. New delivery systems for intranasal steroids and antihistamines, recombinant allergens, advances in allergen immunotherapy delivery, and biologics will improve current management options. These developments will aid the otolaryngologist in diagnosing and treating allergy and related diseases.

Diagnostic Accuracy of Urinary LTE4 Measurement to Predict Aspirin-Exacerbated Respiratory Disease in Patients with Asthma

BACKGROUND

Patients with aspirin-exacerbated respiratory disease (AERD) are distinguished from patients with aspirin-tolerant asthma (ATA) by significantly higher baseline concentrations of urinary leukotriene E₄ (uLTE₄). However, an overlap between the individual values of the groups exists.

OBJECTIVE

The objective of this study was to estimate the discriminative value of uLTE₄ concentration in differentiating between patients with AERD and patients with ATA and evaluate the diagnostic accuracy of uLTE₄ measurement alone and added to clinical parameters to predict AERD diagnosis in patients with asthma.

METHODS

Clinical data were collected from questionnaires. Spirometry, skin prick tests, total IgE, and blood eosinophilia were evaluated. ULTE₄ concentrations were measured in morning urine samples by enzyme-linked immune assay (ELISA).

RESULTS

Patients with AERD (n = 247) had significantly higher uLTE₄ concentrations than those with ATA (n = 239). The uLTE₄ concentration of 800.0 pg/mg creatinine as measured by ELISA on a spot sample best discriminated the 2 groups (area under the curve 0.7; 95% confidence interval 0.66-0.74, sensitivity 49%, specificity 81%). The positive predictive value and negative predictive value (NPV), after considering the prevalence of AERD in the population of asthmatics, were 16% and 96%, respectively. Nasal polyps, upper airway symptoms, nasal corticosteroid treatment, asthma exacerbations, forced expiratory volume in the 1 second predicted, and age of asthma onset were independent predictors of AERD diagnosis. The addition of elevated uLTE₄ concentration to the set of clinical parameters enhanced slightly the prediction of AERD diagnosis beyond the level predicted by clinical parameters (P = .036).

CONCLUSIONS

A set of typical clinical parameters has a superior accuracy in prediction of AERD diagnosis than the measurement of uLTE₄ concentration alone. The addition of uLTE₄ concentration to clinical parameters slightly enhances the prediction of AERD diagnosis, especially due to a high NPV.

Potential Biomarkers for NSAID-Exacerbated Respiratory Disease

Asthma is a common chronic disease with several variant phenotypes and endotypes. NSAID-exacerbated respiratory disease (NERD) is one such endotype characterized by asthma, chronic rhinosinusitis (CRS) with nasal polyps, and hypersensitivity to aspirin/cyclooxygenase-1 inhibitors. NERD is more associated with severe asthma than other asthma phenotypes. Regarding diagnosis, aspirin challenge tests via the oral or bronchial route are a standard diagnostic method; reliable in vitro diagnostic tests are not available. Recent studies have reported various biomarkers of phenotype, diagnosis, and prognosis. In this review, we summarized the known potential biomarkers of NERD that are distinct from those of aspirin-tolerant asthma. We also provided an overview of the different NERD subgroups.

Urinary Leukotriene E4 to Determine Aspirin Intolerance in Asthma: A Systematic Review and Meta-Analysis

BACKGROUND

Urinary leukotriene E4 (ULTE4) may be a biomarker that distinguishes aspirin-intolerant asthma from other asthma subtypes.

OBJECTIVE

To estimate the diagnostic testing accuracy of ULTE4 as a marker of aspirin intolerance in patients with asthma using previously published studies.

METHODS

We identified relevant clinical studies from a systematic review of English and non-English articles using MEDLINE, EMBASE, and CENTRAL (inception to February 10, 2015). Articles were screened at the abstract and full-text level by 2 independent reviewers. We included previously published studies that analyzed ULTE4 in human subjects with asthma characterized as having or not having aspirin intolerance on the basis of a specified definition: convincing history of aspirin intolerance, positive aspirin challenge, or both as the criterion standard. Individual-level data points from all included studies were obtained and analyzed.

RESULTS

The search strategy identified 867 potential articles, of which 86 were reviewed at the full-text level and 10 met criteria for inclusion. The sensitivity, specificity, positive predictive value, and negative predictive values of ULTE4 to determine aspirin intolerance in subjects with asthma were 0.55, 0.82, 0.75, and 0.66 (Amersham-enzyme immunoassay); 0.76, 0.77, 0.70, and 0.78 (Cayman-enzyme immunoassay); 0.70, 0.81, 0.86, and 0.79 (mass spectrometry); and 0.81,0.79, 0.65, and 0.88 (radioimmunoassay) at optimal thresholds of 192, 510, 167 to 173, and 66 to 69 pg/mg Cr, respectively. The diagnostic odds ratio for each methodology was 6.0, 11.9, 10.5, and 19.1, respectively.

CONCLUSIONS

ULTE4 is a marker for aspirin-intolerant asthma and could potentially be used as a clinical test to identify the risk of aspirin intolerance in subjects with asthma.

The Journal of Allergy and Clinical Immunology: In Practice - 2016 Year in Review

As editors, we concluded that it would be helpful to our readers to write a Year in Review article that highlights the Review, Original, and Clinical Communication articles published in 2016 in The Journal of Allergy and Clinical Immunology: In Practice. We summarized articles on the topics of asthma, rhinitis/rhinosinusitis, food allergy, anaphylaxis, drug allergy, urticarial/angioedema, eosinophilic disorders, and immunodeficiency. Within each topic, epidemiologic findings are presented, relevant aspects of prevention are described, and diagnostic and therapeutic advances are enumerated. Diagnostic tools described include history, skin tests, and in vitro tests. Treatments discussed include behavioral therapy, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We hope this review will help you, our readers, consolidate and use this extensive and practical knowledge for the benefit of your patients.

Aspirin-exacerbated respiratory disease: Prevalence, diagnosis, treatment, and considerations for the future

Aspirin-exacerbated respiratory disease (AERD) is a late onset condition characterized by the Samter triad (aspirin sensitivity [as well as sensitivity to any nonselective cyclooxygenase inhibitor], nasal polyps, asthma) and additional features, including eosinophilic chronic rhinosinusitis, hypereosinophilia, anosmia, frequent absence of atopy, and, intolerance to ingestion of red wine and other alcoholic beverages. The diagnosis is rare, and, because of this, it is also often missed by physicians. However, it is highly overexpressed in patients with severe asthma (and severe chronic rhinosinusitis with nasal polyps), which makes its recognition essential. For this review, we considered mechanisms involved in the pathogenesis of this disease and discussed the clinical symptoms of AERD. We also discussed the role of aspirin desensitization in the treatment of AERD. Also, we considered medications (e.g, leukotriene modifiers) and surgical interventions that have a role in the treatment of AERD.

A Review of Classification Schemes for Chronic Rhinosinusitis with Nasal Polyposis Endotypes

Objective

The recent development of endotypes to categorize disease variants of chronic rhinosinusitis (CRS) reflects an evolving understanding of the various pathophysiologic and pathogenetic mechanisms that contribute to the clinical heterogeneity of CRS manifestations. This review highlights popular endotype‐based criteria used to define different CRS with nasal polyposis (CRSwNP) subtypes and further discusses the emerging therapeutic advances for each classificatory approach.

Data Sources

PubMed literature review.

Methods

A review of the current literature was conducted to determine present‐day uses of immunologic and molecular profiles in the CRSwNP disease spectrum to identify specific endotypes.

Results

Four distinct but overlapping classification schemes have emerged to define endotypes within the CRSwNP phenotype: 1) type 2 cytokine‐based approach, 2) eosinophil‐based approach, 3) immunoglobulin (Ig)E‐based approach, and 4) cysteinyl based approach. The identification of key inflammatory biomarkers related to these CRSwNP endotypes has broadened the classification of CRS beyond common phenotypic expressions. Furthermore, CRSwNP endotypes may improve the selection of CRSwNP patients who are suitable candidates for biomarker‐specific treatment options, such as anti‐interleukin‐5; anti‐IgE; and platelet‐directed therapies.

Conclusion

Chronic rhinosinusitis endotyping with key biomarker patterns of inflammation allows for improved diagnostic and potentially therapeutic classifications of CRSwNP variants.