Possible involvement of mast-cell activation in aspirin provocation of aspirin-induced asthma

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.

Omalizumab ameliorates extrarespiratory symptoms in patients with aspirin-exacerbated respiratory disease

BACKGROUND

Omalizumab, an anti-IgE antibody, has clinical efficacy against respiratory symptoms of aspirin-exacerbated respiratory disease (AERD). However, some patients with AERD also present with extrarespiratory (chest, gastrointestinal, and/or cutaneous) symptoms, which are resistant to conventional treatment but can be alleviated by systemic corticosteroids.

OBJECTIVE

We evaluated the efficacy of omalizumab on extrarespiratory symptoms related to AERD.

METHODS

In study 1, a total of 27 consecutive patients with AERD initially prescribed omalizumab at Sagamihara National Hospital between July 2009 and March 2019 were retrospectively studied. Frequency of exacerbations of AERD-related extrarespiratory symptoms was compared before and after omalizumab treatment. In study 2, we reported 3 AERD cases with aspirin challenge-induced extrarespiratory symptoms among patients studied in our previous randomized trial (registration UMIN000018777), which evaluated the effects of omalizumab on hypersensitivity reactions during aspirin challenge to AERD patients. Extrarespiratory symptoms induced during the aspirin challenge were compared between placebo and omalizumab phases.

RESULTS

In study 1, omalizumab treatment was associated with decrease in frequency of exacerbation of chest pain (no. [%] of patients with exacerbation frequency ≥1 time per year, 6 [22.2%] vs 0; P < .001), gastrointestinal symptoms (9 [33.3%] vs 2 [7.4%]; P = .016), and cutaneous symptoms (16 [59.3%] vs 2 [7.4%]; P < .001), even under conditions of treatment-related reduction in systemic corticosteroid dose. Omalizumab also attenuated all the extrarespiratory symptoms during aspirin challenge in study 2.

CONCLUSION

Omalizumab ameliorated extrarespiratory symptoms at baseline (without aspirin exposure) and during aspirin challenge.

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.

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.

Nontryptase Urinary and Hematologic Biomarkers of Mast Cell Expansion and Mast Cell Activation: Status 2022

Quantitation of urinary metabolites of histamine, prostaglandin D₂, and leukotriene E₄ can fill the gap in our current efforts to improve diagnosis and management of symptomatic patients with systemic mastocytosis, and/or mast cell activation syndrome, In addition, patients symptomatic due to mast cell activation but who do not meet all the criteria for mast cell activation syndrome can have elevated baseline mediator metabolites. Serum tryptase levels have been the workhorse in diagnosing these disorders, but it has several drawbacks including the need to obtain acute and baseline samples, which require 2 visits to health care facilities and 2 venipunctures. Recently, increased baseline tryptase level has been reported in hereditary alpha tryptasemia, complicating diagnostic possibilities of an increased baseline tryptase level. Furthermore, no treatment can specifically be targeted at tryptase itself. In contrast, the finding of 1 or more elevated urinary levels of histamine, prostaglandin D₂, and/or leukotriene E₄ metabolites (1) greatly narrows diagnostic possibilities for causes of symptoms; (2) informs the practitioner what specific metabolic pathways are involved; and (3) targets the treatment in a specific, direct fashion. As a bonus, baseline spot/random urine samples can be obtained by the patients themselves and repeated at exactly the correct time when symptoms occur.

Urinary Leukotriene E4 as a Biomarker in NSAID-Exacerbated Respiratory Disease (N-ERD): a Systematic Review and Meta-analysis

PURPOSE OF REVIEW

Non-steroidal exacerbated respiratory disease (N-ERD) currently requires aspirin challenge testing for diagnosis. Urinary leukotriene E4 (uLTE₄) has been extensively investigated as potential biomarker in N-ERD. We aimed to assess the usefulness of uLTE₄ as a biomarker in the diagnosis of N-ERD.

RECENT FINDINGS

N-ERD, formerly known as aspirin-intolerant asthma (AIA), is characterised by increased leukotriene production. uLTE₄ indicates cysteinyl leukotriene production, and a potential biomarker in N-ERD. Although several studies and have examined the relationship between uLTE₄ and N-ERD, the usefulness of uLTE₄ as a biomarker in a clinical setting remains unclear.

FINDINGS

Our literature search identified 38 unique eligible studies, 35 were included in the meta-analysis. Meta-analysis was performed (i.e. pooled standardised mean difference (SMD) with 95% confidence intervals (95% CI)) and risk of bias assessed (implementing Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy (Cochrane DTA)). Data from 3376 subjects was analysed (1354 N-ERD, 1420 ATA, and 602 HC). uLTE₄ was higher in N-ERD vs ATA (n = 35, SMD 0.80; 95% CI 0.72-0.89). uLTE4 increased following aspirin challenge in N-ERD (n = 12, SMD 0.56; 95% CI 0.26-0.85) but not ATA (n = 8, SMD 0.12; CI - 0.08-0.33). This systematic review and meta-analysis showed that uLTE₄ is higher in N-ERD than ATA or HC. Likewise, people with N-ERD have greater increases in uLTE₄ following aspirin challenge. However, due to the varied uLTE₄ measurement and result reporting practice, clinical utility of these findings is limited. Future studies should be standardised to increase clinical significance and interpretability of the results.

Triggers of Exacerbation in Chronic Urticaria and Recurrent Angioedema-Prevalence and Relevance

Patients with urticaria and angioedema often have triggers that cause an outbreak or a swelling episode or worsen their chronic condition. Exploring these factors with each patient may result in better understanding and control of their disease. Patients should be advised to avoid known triggers, if feasible, or prepare to prevent or control an exacerbation with appropriate pretreatment if avoidance is not possible. In this review, we describe and discuss a variety of factors for which there is evidence that they cause or exacerbate chronic spontaneous urticaria and angioedema. These potentially exacerbating factors include drugs, food additives, and naturally occurring pseudoallergens, mental stress, and trauma.

Aspirin Actions in Treatment of NSAID-Exacerbated Respiratory Disease

Non-steroidal Anti-inflammatory drugs (NSAID)-exacerbated respiratory disease (N-ERD) is characterized by nasal polyposis, chronic rhinosinusitis, adult-onset asthma and hypersensitive reactions to cyclooxygenase-1 (COX-1) inhibitors. Among the available treatments for this disease, a combination of endoscopic sinus surgery followed by aspirin desensitization and aspirin maintenance therapy has been an effective approach. Studies have shown that long-term aspirin maintenance therapy can reduce the rate of nasal polyp recurrence in patients with N-ERD. However, the exact mechanism by which aspirin can both trigger and suppress airway disease in N-ERD remains poorly understood. In this review, we summarize current knowledge of aspirin effects in N-ERD, cardiovascular disease, and cancer, and consider potential mechanistic pathways accounting for the effects of aspirin in N-ERD.

Divergent PGD2 and leukotriene C4 metabolite excretion following aspirin therapy: Ten patients with systemic mastocytosis

Aspirin-exacerbated respiratory disease and some cases of chronic idiopathic urticaria are disorders in which increased baseline urinary excretion of leukotriene(LT)E4 further increases following aspirin administration. Increased urinary excretion of the metabolites of prostaglandin D2, 11β-prostaglandin(PG)F2α and (2,3-dinor)-11β-PGF2α, have been documented in systemic mastocytosis (SM) and in mast cell activation syndrome (MCAS). Symptoms due to increased baseline and/or episodic release of PGD2 can be prevented with aspirin, an inhibitor of cyclooxygenase (COX)1 and COX2. Here by retrospective chart review we discovered 8 of 10 patients with SM in whom normalization of an elevated urinary (2,3-dinor)-11β-PGF2α occurred with aspirin therapy also had a parallel increased excretion of LTE4 by an average of nearly 13-fold. How widespread this phenomenon occurs in SM is unknown; however, this occurrence needs to be considered when interpreting changes in these urinary mast cell mediator metabolites during aspirin therapy.

Genetic Variants in Cytosolic Phospholipase A2 Associated With Nonsteroidal Anti-Inflammatory Drug-Induced Acute Urticaria/Angioedema

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the main triggers of drug hypersensitivity reactions, probably due to their high consumption worldwide. The most frequent type of NSAID hypersensitivity is NSAID cross-hypersensitivity, in which patients react to NSAIDs from different chemical groups in the absence of a specific immunological response. The underlying mechanism of NSAID cross-hypersensitivity has been linked to cyclooxygenase (COX)-1 inhibition causing an imbalance in the arachidonic acid pathway. Despite NSAID-induced acute urticaria/angioedema (NIUA) being the most frequent clinical phenotype, most studies have focused on NSAID-exacerbated respiratory disease. As NSAID cross-hypersensitivity reactions are idiosyncratic, only appearing in some subjects, it is believed that individual susceptibility is under the influence of genetic factors. Although associations with polymorphisms in genes from the AA pathway have been described, no previous study has evaluated the potential role of cytosolic phospholipase A2 (cPLA2) variants. This enzyme catalyzes the initial hydrolysis of membrane phospholipids to release AA, which can be subsequently metabolized into eicosanoids. Here, we analyzed for the first time the overall genetic variation in the cPLA2 gene (PLA2G4A) in NIUA patients. For this purpose, a set of tagging single nucleotide polymorphisms (tagSNPs) in PLA2G4A were selected using data from Europeans subjects in the 1,000 Genomes Project, and genotyped with the iPlex Sequenom MassArray technology. Two independent populations, each comprising NIUA patients and NSAID-tolerant controls, were recruited in Spain, for the purposes of discovery and replication, comprising a total of 1,128 individuals. Fifty-eight tagSNPs were successfully genotyped in the discovery cohort, of which four were significantly associated with NIUA after Bonferroni correction (rs2049963, rs2064471, rs12088010, and rs12746200). These polymorphisms were then genotyped in the replication cohort: rs2049963 was associated with increased risk for NIUA after Bonferroni correction under the dominant and additive models, whereas rs12088010 and rs12746200 were protective under these two inheritance models. Our results suggest a role for PLA2G4A polymorphisms in NIUA. However, further studies are required to replicate our findings, elucidate the mechanistic role, and evaluate the participation of PLA2G4A variants in other phenotypes induced by NSAID cross-hypersensitivity.

Platelet-Adherent Leukocytes Associated With Cutaneous Cross-Reactive Hypersensitivity to Nonsteroidal Anti-Inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most highly consumed drugs worldwide and the main triggers of drug hypersensitivity reactions. The most frequent reaction, named cross-reactive NSAID-hypersensitivity, is due to the pharmacological activity of these drugs by blocking the cyclooxygenase-1 enzyme. Such inhibition leads to cysteinyl-leukotriene synthesis, mainly LTE4, which are responsible for the reaction. Although the complete molecular picture of the underlying mechanisms remains elusive, the participation of platelet-adherent leukocytes (CD61⁺) and integrins have been described for NSAID-exacerbated respiratory disease (NERD). However, there is a lack of information concerning NSAID-induced urticaria/angioedema (NIUA), by far the most frequent clinical phenotype. Here we have evaluated the potential role of CD61⁺ leukocytes and integrins (CD18, CD11a, CD11b, and CD11c) in patients with NIUA, and included the other two phenotypes with cutaneous involvement, NSAID-exacerbated cutaneous disease (NECD) and blended reactions (simultaneous skin and airways involvement). A group NSAID-tolerant individuals was also included. During the acute phase of the reaction, the three clinical phenotypes showed increased frequencies of CD61⁺ neutrophils, eosinophils, and monocytes compared to controls, which correlated with urinary LTE4 levels. However, no correlation was found between these variables at basal state. Furthermore, increased expressions of CD18 and CD11a were found in the three CD61⁺ leukocytes subsets in NIUA, NECD and blended reactions during the acute phase when compared with CD61^-leukocyte subpopulations. During the acute phase, CD61⁺ neutrophils, eosinophils and monocytes showed increased CD18 and CD11a expression when compared with CD61⁺ leukocytes at basal state. No differences were found when comparing controls and CD61⁺ leukocytes at basal state. Our results support the participation of platelet-adherent leukocytes and integrins in cutaneous cross-hypersensitivity to NSAIDs and provide a link between these cells and arachidonic acid metabolism. Our findings also suggest that these reactions do not involve a systemic imbalance in the frequency of CD61⁺ cells/integrin expression or levels of LTE4, which represents a substantial difference to NERD. Although further studies are needed, our results shed light on the molecular basis of cutaneous cross-reactive NSAID-hypersensitivity, providing potential targets for therapy through the inhibition of platelet-leukocyte interactions.

Increased Basal Blood Histamine Levels in Patients with Self-Reported Hypersensitivity to Non-Steroidal Anti-Inflammatory Drugs

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) represent one of the most prevalent causes of drug hypersensitivity reactions (DHRs), yet the underlying processes are far from clear. Despite the established role of histamine in allergic reactions, its precise implication in DHRs is elusive.

OBJECTIVES

This study aimed to explore the connection of basal blood histamine levels to the reported NSAID hypersensitivity.

METHODS

Sixteen patients reporting hypersensitivity reactions to a single or multiple NSAIDs and/or paracetamol and 18 healthy volunteers serving as the normal control group enrolled in the study. The medical history was recorded and histamine was quantified spectrophotofluorometrically in whole peripheral blood and plasma.

RESULTS

Compared to the normal group, plasma but not whole blood histamine levels were significantly higher in patients (p < 0.001), mainly in the subgroup reporting hypersensitivity to a single agent (p < 0.001). Plasma histamine levels were significantly correlated with the culprit drug selectivity for cyclooxygenase (COX) isozymes (p < 0.001), with higher levels being obtained in patients reporting reactions to COX-1 than to COX-2 selective inhibitors (p < 0.05).

CONCLUSIONS

The findings provide first evidence connecting basal blood histamine levels to the reported NSAID-triggered DHRs. Prospective studies are expected to decipher the contribution of histamine-associated parameters to the mechanisms underlying DHRs.

Aspirin-exacerbated respiratory disease (AERD): Current understanding of AERD

The characteristics in AERD are severe adult-onset asthma, eosinophilic rhinosinusitis with nasal polyposis, and CysLT overproduction. The cause of AERD have remained unclear, however the decrease in the production of PGE2 caused by the reduction in COX-2 activity is considered to main pathological mechanism of AERD. The mast cell activation and the interaction between platelets and granulocytes are lead to the CysLT overproduction and severe eosinophilic inflammation. The ongoing activation of mast cells is important key pathogenesis in not only stable AERD but exacerbated AERD by aspirin and NSAIDs. In recent years, type 2 inflammation caused by ILC2 activation in patients with AERD have been attracting attention. Omalizumab is effective option for AERD via suppression of mast cell activation and CysLT overproduction. Dupilumab improves sinus symptoms especially in patients with AERD. In near future, anti-platelet drug, CRTH2 antagonist, and anti-TSLP antibody may be useful candidates of therapeutic options in patients with AERD.

Eicosanoid mediator profiles in different phenotypes of nonsteroidal anti-inflammatory drug-induced urticaria

BACKGROUND

The role of arachidonic acid metabolites in NSAID-induced hypersensitivity has been studied in depth for NSAID-exacerbated respiratory disease (NERD) and NSAID-exacerbated cutaneous disease (NECD). However, no information is available for NSAID-induced urticarial/angioedema (NIUA), despite it being the most frequent clinical entity induced by NSAID hypersensitivity. We evaluated changes in leukotriene and prostaglandin metabolites for NIUA patients, using patients with NECD and single-NSAID-induced urticaria/angioedema or anaphylaxis (SNIUAA) for comparison.

METHODS

Urine samples were taken from patients with confirmed NSAID-induced urticaria and healthy controls, at baseline and at various time intervals after ASA administration. Eicosanoid measurement was performed using high-performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

RESULTS

No differences were found between groups at baseline. Following ASA administration, LTE4 and 9α,11β-PGF2 levels were increased in both NIUA and NECD patients compared to baseline, rising initially, before decreasing toward initial levels. In addition, the levels of these metabolites were higher in NIUA and NECD when compared with the SNIUAA and control groups after ASA administration. No changes were found with respect to baseline values for SNIUAA and control groups.

CONCLUSIONS

We present for the first time data regarding the role of COX-1 inhibition in NIUA. Patients with this entity show a similar pattern eicosanoid levels following ASA challenge to those with NECD. Further studies will help ascertain the cell populations involved and the underlying molecular mechanisms.

Pathogenesis of NSAID-induced reactions in aspirin-exacerbated respiratory disease

It is well-established that following ingestion of aspirin or any other inhibitor of cyclooxygenase-1, patients with Samter's disease, or aspirin-exacerbated respiratory disease (AERD) develop the sudden onset of worsening respiratory clinical symptoms, which usually involves nasal congestion, rhinorrhea, wheezing and bronchospasm. Gastrointestinal distress, nausea, a pruritic rash and angioedema can also occasionally develop. However, the underlying pathologic mechanism that drives these clinical reactions remains elusive. Pretreatment with medications that inhibit the leukotriene pathway decreases the severity of clinical reactions, which points to the involvement of cysteinyl leukotrienes (cysLTs) in the pathogenesis of these aspirin-induced reactions. Furthermore, studies of aspirin challenges in carefully-phenotyped patients with AERD have confirmed that both proinflammatory lipid mediators, predominantly cysLTs and prostaglandin (PG) D₂, and the influx of effector cells to the respiratory tissue, contribute to symptom development during aspirin-induced reactions. Mast cells, which have been identified as the major cellular source of cysLTs and PGD₂, are likely to be major participants in the acute reactions, and are an attractive target for future pharmacotherapies in AERD. Although several recent studies support the role of platelets as inflammatory effector cells and as a source of cysLT overproduction in AERD, it is not yet clear whether platelet activation plays a direct role in the development of the aspirin-induced reactions. To further our understanding of the pathogenesis of aspirin-induced reactions in AERD, and to broaden the pharmacotherapeutic options available to these patients, additional investigations with targeted clinical trials will be required.

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.

Smoking Cessation as a Possible Risk Factor for the Development of Aspirin-Exacerbated Respiratory Disease in Smokers

BACKGROUND

The pathogenesis of aspirin-exacerbated respiratory disease (AERD) is characterized by the low expression of cyclooxygenase-2 (COX-2) in airway epithelia, which decreases the production of prostaglandin E₂ (PGE₂). Conversely, cigarette smoke stimulates COX-2 expression in airway epithelia. Therefore, it was hypothesized that the development of AERD would be suppressed by elevated PGE₂ levels in smokers, and smoking cessation might increase susceptibility to AERD.

OBJECTIVE

The objective of this study was to evaluate the relationship between smoking and the risk of AERD development.

METHODS

The smoking status of patients with AERD (n = 114) was compared with 2 control groups with aspirin-tolerant asthma (ATA), patients diagnosed by a systemic aspirin provocation test (ATA-1, n = 83) and outpatients randomly selected from a large-scale dataset (ATA-2, n = 914), as well as a healthy control group (HC, n = 2313).

RESULTS

At the age of asthma onset, there was a low frequency of current smokers (9.7%), but a high frequency of past smokers (20.2%) in the AERD group compared with the ATA-1 (20.5% and 12.0% for current and past smokers, respectively), ATA-2 (24.5% and 10.3%, respectively), and HC group (26.2% and 12.6%, respectively). After adjustment for confounding variables, AERD was positively associated with smoking cessation between 1 and 4 years before disease onset compared with the ATA-2 group (adjusted odds ratio [aOR] 4.63, 95% confidence interval [CI]: 2.16-9.93) and the HC group (aOR 4.09, 95% CI: 2.07-8.05), implying that smoking cessation was followed by the development of AERD.

CONCLUSION

Smoking cessation may be a risk factor for the development of AERD.

Copy number variation in ALOX5 and PTGER1 is associated with NSAIDs-induced urticaria and/or angioedema

OBJECTIVE

Cross-intolerance to NSAIDs is a class of drug hypersensitivity reaction, of which NSAIDs-induced urticaria and/or angioedema (NIUA) are the most frequent clinical entities. They are considered to involve dysregulation of the arachidonic acid pathway; however, this mechanism has not been confirmed for NIUA. In this work, we assessed copy number variations (CNVs) in eight of the main genes involved in the arachidonic acid pathway and their possible genetic association with NIUA.

MATERIALS AND METHODS

CNVs in ALOX5, LTC4S, PTGS1, PTGS2, PTGER1, PTGER2, PTGER3, and PTGER4 were analyzed using TaqMan copy number assays. Genotyping was carried out by real-time quantitative PCR. Individual genotypes were assigned using the CopyCaller Software. Statistical analysis was carried out using GraphPad prism 5, PLINK, EPIDAT, and R version 3.1.2.

RESULTS AND CONCLUSION

A total of 151 cases and 139 controls were analyzed during the discovery phase and 148 cases and 140 controls were used for replication. CNVs in open reading frames were found for ALOX5, PTGER1, PTGER3, and PTGER4. Statistically significant differences in the CNV frequency between NIUA and controls were found for ALOX5 (Pc=0.017) and PTGER1 (Pc=1.22E-04). This study represents the first analysis showing an association between CNVs in exonic regions of ALOX5 and PTGER1 and NIUA. This suggests a role of CNVs in this pathology that should be explored further.

Mast cells in asthma--state of the art

Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.

FCERI and Histamine Metabolism Gene Variability in Selective Responders to NSAIDS

The high-affinity IgE receptor (Fcε RI) is a heterotetramer of three subunits: Fcε RIα, Fcε RIβ, and Fcε RIγ (αβγ2) encoded by three genes designated as FCER1A, FCER1B (MS4A2), and FCER1G, respectively. Recent evidence points to FCERI gene variability as a relevant factor in the risk of developing allergic diseases. Because Fcε RI plays a key role in the events downstream of the triggering factors in immunological response, we hypothesized that FCERI gene variants might be related with the risk of, or with the clinical response to, selective (IgE mediated) non-steroidal anti-inflammatory (NSAID) hypersensitivity. From a cohort of 314 patients suffering from selective hypersensitivity to metamizole, ibuprofen, diclofenac, paracetamol, acetylsalicylic acid (ASA), propifenazone, naproxen, ketoprofen, dexketoprofen, etofenamate, aceclofenac, etoricoxib, dexibuprofen, indomethacin, oxyphenylbutazone, or piroxicam, and 585 unrelated healthy controls that tolerated these NSAIDs, we analyzed the putative effects of the FCERI SNPs FCER1A rs2494262, rs2427837, and rs2251746; FCER1B rs1441586, rs569108, and rs512555; FCER1G rs11587213, rs2070901, and rs11421. Furthermore, in order to identify additional genetic markers which might be associated with the risk of developing selective NSAID hypersensitivity, or which may modify the putative association of FCERI gene variations with risk, we analyzed polymorphisms known to affect histamine synthesis or metabolism, such as rs17740607, rs2073440, rs1801105, rs2052129, rs10156191, rs1049742, and rs1049793 in the HDC, HNMT, and DAO genes. No major genetic associations with risk or with clinical presentation, and no gene-gene interactions, or gene-phenotype interactions (including age, gender, IgE concentration, antecedents of atopy, culprit drug, or clinical presentation) were identified in patients. However, logistic regression analyses indicated that the presence of antecedents of atopy and the DAO SNP rs2052129 (GG) were strongly related (P < 0.001 and P = 0.005, respectively) with selective hypersensitivity to ibuprofen. With regard to patients with selective hypersensitivity to ASA, men were more prone to develop such a reaction than women (P = 0.011), and the detrimental DAO SNP rs10156191 in homozygosity increased the risk of developing such hypersensitivity (P = 0.039).

[Adaptive desensitization for acetylsalicylic acid hypersensitivity: A success story?]

BACKGROUND

Adaptive desensitization still remains the only causative therapy for acetylsalicylic acid (ASA) hypersensitivity and is carried out nearly worldwide. To date there are hardly any data available on disease development under current desensitization therapy and longitudinal data in particular are missing.

STUDY DESIGN

Out of a large collective of patients with proven hypersensitivity to ASA, 194 patients with initiated desensitization treatment were observed for periods up to 5 years (average 32 months).

RESULTS

Patients with immediate reactions to systemic challenge tests revealed a response rate of 77% after 12 months of therapy. In this period 12% reached complete remission, 38% showed a clear reduction in symptoms, 32% reached partial remission, 13% remained unchanged and 5% suffered from disease progression.

CONCLUSION

Adaptive desensitization therapy for hypersensitivity to ASA has been shown to be an effective causative therapy and chronic hyperplastic sinusitis as well as bronchial asthma could be improved. For the determination of maintenance dosages and required time periods more data are needed.

Platelet activation markers overexpressed specifically in patients with aspirin-exacerbated respiratory disease

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD) is characterized by respiratory reactions on ingestion of COX-1 inhibitors and cysteinyl leukotriene overproduction. The hypersensitivity reaction is induced by low doses of aspirin that inhibit COX-1 in platelets.

OBJECTIVE

We sought to explore the role of platelets in the pathogenesis of AERD in patients under stable conditions and during an aspirin challenge test.

METHODS

Stable patients with AERD (n = 30), aspirin-tolerant asthma (ATA; n = 21), or idiopathic chronic eosinophilic pneumonia (n = 10) were enrolled. Platelet activation was estimated based on expression levels of P-selectin (CD62P), CD63, CD69, and GPIIb/IIIa (PAC-1) in peripheral platelets; percentages of circulating platelet-adherent leukocytes; and plasma levels of soluble P-selectin (sP-selectin) and soluble CD40 ligand (sCD40L).

RESULTS

In the stable condition, expression of all surface markers on platelets, the percentage of platelet-adherent eosinophils, and the plasma levels of sP-selectin and sCD40L were significantly higher in patients with AERD compared with those in patients with ATA. P-selectin and CD63 expression on platelets and plasma sP-selectin and sCD40L levels were positively correlated with the percentage of platelet-adherent eosinophils. Among these markers, P-selectin expression and plasma sP-selectin levels positively correlated with urinary concentrations of leukotriene E4. Additionally, plasma sP-selectin and sCD40L levels were negatively correlated with lung function. In contrast, platelet activation markers in patients with AERD did not change during the aspirin challenge test.

CONCLUSION

Peripheral platelets were activated more in patients with stable AERD compared with those in patients with stable ATA, patients with idiopathic chronic eosinophilic pneumonia, and control subjects. Platelet activation was involved in cysteinyl leukotriene overproduction and persistent airflow limitations in patients with AERD.

9α,11β-PGF2, a Prostaglandin D2 Metabolite, as a Marker of Mast Cell Activation in Bee Venom-Allergic Patients

Mast cell (MC) mediators, among them prostaglandin D₂ (PGD₂) and 9α,11β-PGF₂, PGD₂’s metabolite, play a key role in allergic reactions, including bee venom anaphylaxis (BVA). Assessment of these mediators has never been performed in BVA. The aim of the study was to assess the activation of MC during in vivo provocation with bee venom (BV) and to measure PGD₂ and 9α,11β-PGF₂ in the course of an allergen challenge. The second aim was to determine if assessment of these mediators could be useful for predicting adverse events during venom immunotherapy (VIT). In 16 BV-VIT patients and 12 healthy subjects, levels of PGD₂ and 9α,11β-PGF₂ were assessed during BV provocation by means of the skin chamber method. Chamber fluids, collected at 5 and 15 min, were analyzed for both mediators by gas chromatography mass spectrometry negative ion chemical ionization. BVA in comparison to non-allergic patients had a significantly higher ratio of 9α,11β-PGF₂ in allergen-challenged chambers to 9α,11β-PGF₂ in allergen-free chambers after 15 min of provocation (p = 0.039). Allergen challenge resulted in a significant increase of 9α,11β-PGF₂ levels between 5 and 15 min after provocation only in BVA patients (p < 0.05). Analysis of log-transformed PGD2 levels showed significant difference between changes in PGD₂ concentration between BVA and healthy subjects. No study patient developed adverse reactions during. 9α,11β-PGF₂ is actively generated during the early allergic response to BV. Skin chamber seems to be a promising, non-invasive and safe model of in vivo allergen provocation in BV-allergic patients. High or low levels of both mediators do not predict occurrence of adverse events during VIT.

Aspirin desensitization: useful treatment for chronic rhinosinusitis with nasal polyps (CRSwNP) in aspirin-exacerbated respiratory disease (AERD)?

Aspirin intolerance syndrome is due to disturbances in the arachidonic acid metabolism implicating both the lipoxygenase and cyclooxygenase pathways. This results in imbalances of eicosanoid, leukotriene and prostaglandin synthesis. Thus, preinflammatory cysteinyl leukotrienes increase and antiinflammatory prostaglandins (PG) such as PGE2 decrease. Clinically, intolerance reactions to nonsteroidal antiinflammatory drugs (NSAIDs) can lead to different clinical manifestations; five phenotypes of the aspirin intolerance syndrome are listed in the ENDA classification. Aspirin-exacerbated respiratory disease (AERD) is the most common phenotype characterized by an eosinophil-dominated inflammatory disease of the airways that presents clinically with nasal polyps, chronic sinusitis and bronchial asthma. About 34 % of patients with aspirin-induced asthma and rhinosinusitis are thought to have AERD. Important biochemical findings in many AERD patients are increased basal leukotriene levels (at least in cell cultures) that excessively increase after intake of COX-1 inhibitors. Aspirin desensitization uses the repetitive application of aspirin to induce a tolerance to NSAIDs, especially COX-1 inhibitors. After a dose-increase phase reaching a threshold dose, a dose-continuation phase is performed. For application, the nasal, bronchial, oral and intravenous routes have been described. Aspirin desensitization has been proven to be efficacious and safe and was able to reduce the need for other medications in AERD patients.

Variability in histamine receptor genes HRH1, HRH2 and HRH4 in patients with hypersensitivity to NSAIDs

Aim: Histamine plays an important role in the pathogenesis of allergic diseases. Genetic variations in histamine receptors (HRH) may influence the expression of allergic diseases. This study analyzes the association between HRH variants and NSAID hypersensitivity reactions. Patients & methods: The authors analyzed copy number variations (CNVs) and common functional SNPs in genes HRH1, HRH2 and HRH4 in 442 unrelated patients with hypersensitivity to NSAIDs and in 414 healthy unrelated controls. Results: The authors identified, both in patients and control subjects, individuals carrying CNVs in HRH genes. The most common genotype corresponded to two copies of each gene, but carriers of one or three copies of HRH1 (5% of individuals), HRH2 (1.1%) and HRH4 genes (0.9%) were also identified. Conclusion: For the first time, we describe CNVs in human HRH genes. Neither common functional SNPs in HRH genes nor CNVs influenced the risk of developing hypersensitivity to NSAIDs.

Original submitted 31 May 2013; Revision submitted 7 August 2013

Pathogenesis of aspirin-exacerbated respiratory disease and reactions

Physiologic and pharmacologic studies support the hypothesis that aspirin-exacerbated respiratory disease (AERD) involves fundamental dysregulation in the production of and end-organ responsiveness to both antiinflammatory eicosanoids (prostaglandin E2) and proinflammatory effectors (cysteinyl leukotrienes). The acquired nature of AERD implies a disturbance in a potential epigenetic control mechanism of the relevant mediator systems, which may be a result of incompletely clarified environmental factors (eg, viral or bacterial infections, inhaled pollutants).

Biochemical pathogenesis of aspirin exacerbated respiratory disease (AERD)

Aspirin exacerbated respiratory disease (AERD) is a distinct clinical entity characterized by eosinophilic rhinosinusitis, asthma and often nasal polyposis. Exposure to aspirin or other nonsteroid anti-inflammatory drugs (NSAIDs) exacerbates bronchospasms with asthma and rhinitis. Disease progression suggests a skewing towards TH2 type cellular response along with moderate to severe eosinophil and mast cell infiltration. Alterations in upper and lower airway cellular milieu with abnormalities in eicosanoid metabolism and altered eicosanoid receptor expression are the key features underlying AERD pathogenesis. Dysregulation of arachidonic acid (AA) metabolism, notably reduced prostaglandin E2 (PGE2) synthesis compared to their aspirin tolerant counterpart and relatively increased PGD2 production, a TH2/eosinophil chemoattractant are reported in AERD. Underproduced PGE2 is metabolized by overexpression of 15 prostaglandin dehydrogenase (15-PGDH) to inactive products further reducing PGE2 at real time. This relives the inhibitory effect of PGE2 on 5-lipoxygenase (5-LOX) resulting in overproduction of cysteinyl leukotrienes (CysLTs). Diminished formation of CysLT antagonists called lipoxins (LXs) also augments CysLTs responsiveness. Occasional intake of NSAIDs favors even more 5-LOX product formation, further narrowing the bronchoconstrictive bottle neck, resulting in acute asthmatic exacerbations along with increased mucus production. This review focuses on abnormalities in biochemical and molecular mechanisms in eicosanoid biosynthesis, eicosanoid receptor dysregulation and associated polymorphisms with special reference to arachidonic acid metabolism in AERD.

The diamine oxidase gene is associated with hypersensitivity response to non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are the drugs most frequently involved in hypersensitivity drug reactions. Histamine is released in the allergic response to NSAIDs and is responsible for some of the clinical symptoms. The aim of this study is to analyze clinical association of functional polymorphisms in the genes coding for enzymes involved in histamine homeostasis with hypersensitivity response to NSAIDs. We studied a cohort of 442 unrelated Caucasian patients with hypersensitivity to NSAIDs. Patients who experienced three or more episodes with two or more different NSAIDs were included. If this requirement was not met diagnosis was established by challenge. A total of 414 healthy unrelated controls ethnically matched with patients and from the same geographic area were recruited. Analyses of the SNPs rs17740607, rs2073440, rs1801105, rs2052129, rs10156191, rs1049742 and rs1049793 in the HDC, HNMT and DAO genes were carried out by means of TaqMan assays. The detrimental DAO 16 Met allele (rs10156191), which causes decreased metabolic capacity, is overrepresented among patients with crossed-hypersensitivity to NSAIDs with an OR  = 1.7 (95% CI  = 1.3–2.1; Pc  = 0.0003) with a gene-dose effect (P = 0.0001). The association was replicated in two populations from different geographic areas (Pc  = 0.008 and Pc  = 0.004, respectively).

Aspirin-intolerant asthma (AIA) assessment using the urinary biomarkers, leukotriene E4 (LTE4) and prostaglandin D2 (PGD2) metabolites

The clinical syndrome of aspirin-intolerant asthma (AIA) is characterized by aspirin/nonsteroidal anti-inflammatory drug intolerance, bronchial asthma, and chronic rhinosinusitis with nasal polyposis. AIA reactions are evidently triggered by pharmacological effect of cyclooxygenase-1 inhibitors. Urine sampling is a non-invasive research tool for time-course measurements in clinical investigations. The urinary stable metabolite concentration of arachidonic acid products provides a time-integrated estimate of the production of the parent compounds in vivo. AIA patients exhibits significantly higher urinary concentrations of leukotriene E(4) (LTE(4)) and 1,15-dioxo-9α-hydroxy-2,3,4,5-tetranorprostan-1,20-dioic acid (tetranor-PGDM), a newly identified metabolite of PGD(2), at baseline. This finding suggests the possibility that increased mast cell activation is involved in the pathophysiology of AIA even in a clinically stable condition. In addition, lower urinary concentrations of primary prostaglandin E(2) and 15-epimer of lipoxin A(4) at baseline in the AIA patients suggest that the impaired anti-inflammatory elements may also contribute to the severe clinical outcome of AIA. During the AIA reaction, the urinary concentrations of LTE(4) and PGD(2) metabolites, including tetranor-PGDM significantly and correlatively increase. It is considered that mast cell activation probably is a pathophysiologic hallmark of AIA. However, despite the fact that cyclooxygenease-1 is the dominant in vivo PGD(2) biosynthetic pathway, the precise mechanism underlying the PGD(2) overproduction resulting from the pharmacological effect of cyclooxygenease-1 inhibitors in AIA remains unknown. A comprehensive analysis of the urinary concentration of inflammatory mediators may afford a new research target in elucidating the pathophysiology of AIA.

Aspirin sensitivity and chronic rhinosinusitis with polyps: a fatal combination

Aspirin-exacerbated respiratory disease (AERD) refers to aspirin sensitivity, chronic rhinosinusitis (CRS), nasal polyposis, asthma, eosinophil inflammation in the upper and lower airways, urticaria, angioedema, and anaphylaxis following the ingestion of NSAIDs. Epidemiologic and pathophysiological links between these diseases are established. The precise pathogenesis remains less defined, even though there is some progress in the understanding of several molecular mechanisms. Nevertheless, these combinations of diseases in patients classified by AERD constitute a fatal combination and may be difficult to treat with standard medical and surgical interventions. This paper reviews in brief the epidemiology, clinical features, diagnosis, molecular pathogenesis, and specific therapies of patients classified by AERD and postulates future attempts to gain new insights into this disease.

Challenge of isolated sputum cells supports in vivo origin of intolerance reaction to aspirin/non-steroidal anti-inflammatory drugs in asthma

BACKGROUND

There is no in vitro test to diagnose aspirin-intolerant asthma (AIA). The aim of this study was to test if challenge with aspirin of sputum cells from subjects with AIA triggers the release of cysteinyl leukotrienes (CysLTs), known to be mediators of bronchoconstriction in AIA.

METHODS

Sputum induction was performed at baseline and at another visit 2 h after a lysine-aspirin bronchoprovocation in 10 subjects with AIA and 9 subjects with aspirin-tolerant asthma (ATA). The isolated sputum cells were incubated for ex vivo challenge.

RESULTS

Release of CysLTs by sputum cells from patients with AIA was not induced by lysine-aspirin ex vivo, neither when cells were collected at baseline nor in sputum cells recovered after lysine-aspirin-induced bronchoconstriction, whereas release of CysLTs from sputum cells was triggered by an ionophore on both occasions. However, the CysLT levels elicited by the ionophore were higher in the AIA group both at baseline (AIA vs. ATA: 3.3 vs. 1.6 ng/million cells; p < 0.05) and after the lysine-aspirin bronchoprovocation (3.9 vs. 1.7 ng/million cells; p < 0.05). This difference in the amount of CysLTs released between the groups appeared to be related to the number of eosinophils.

CONCLUSIONS

Intolerance to aspirin could not be triggered in sputum cells isolated from subjects with AIA. Together with the previous inability to demonstrate intolerance to non-steroidal anti-inflammatory drugs in isolated blood cells, these results support the requirement of tissue-resident cells in the adverse reaction. However, ex vivo stimulation of sputum cells may be developed into a new test of capacity for LT release in inflammatory cells recovered from airways.

Obesity and aspirin intolerance are risk factors for difficult-to-treat asthma in Japanese non-atopic women

BACKGROUND

Asthma is a clinical syndrome characterized by variabilities in disease expression and severity. The pathophysiological mechanism underlying anti-asthma treatment resistance is also assumed to be different between disease phenotypes.

OBJECTIVE

To elucidate the effect of gender and atopic phenotype on the relationship between clinical factors and the risk of treatment resistance.

METHODS

We compared outpatients with difficult-to-treat asthma (DTA; n = 486) in a tertiary hospital for allergic diseases in central Japan with those with controlled severe asthma (n = 621) with respect to clinical factors including body mass index (BMI) and aspirin intolerance using multivariate logistic regression analysis stratified by gender and atopic phenotype.

RESULTS

When analysis was performed on the entire study populations, obesity (BMI ≥ 30 kg/m(2); adjusted odds ratio (OR) 1.92; 95% confidence interval (95% CI: 1.07-3.43) and aspirin intolerance (OR: 2.56, 95% CI: 1.44-4.57) were found to be the significant risk factors for DTA. However, after the stratification by gender and atopic phenotype, the association between obesity and DTA was significant only in women (OR: 2.76, 95% CI: 1.31-5.78), but not in men (OR: 1.03, 95% CI: 0.38-2.81), and only in non-atopics (OR: 4.03, 95% CI: 1.15-14.08), but not in atopics (OR: 1.54, 95% CI: 0.79-3.02). The similar gender and phenotypic differences were also observed in the association between aspirin intolerance and DTA: namely, the association was significant only in women (OR: 3.96, 95% CI: 1.84-8.50), but not in men (OR: 1.19, 95% CI: 0.46-3.05); and only in non-atopics (OR: 5.49, 95% CI: 1.98-15.19), but not in atopics (OR: 1.39, 95% CI: 0.65-2.98).

CONCLUSIONS AND CLINICAL RELEVANCE

Significant associations of obesity and aspirin intolerance with DTA were observed only in women and in non-atopics. These findings suggest that a phenotype-specific approach is needed to treat patients with DTA.

Urinary concentrations of 15-epimer of lipoxin A(4) are lower in patients with aspirin-intolerant compared with aspirin-tolerant asthma

BACKGROUND

Although an abnormality in arachidonic acid metabolism may be responsible for aspirin-intolerant asthma (AIA), there is little knowledge about the concentrations of urinary lipoxin A(4) (LXA(4)) and the 15-epimer of LXA(4) (15-epi-LXA(4)) in relation to asthma severity in AIA subjects.

OBJECTIVE

The purpose of this study is to estimate urinary LXA(4) and the 15-epimer concentrations to investigate lipoxins in AIA.

METHODS

In this study, we examined AIA, aspirin-tolerant asthma (ATA) and healthy control groups. The AIA and ATA groups were subdivided into the severe asthma and non-severe asthma subgroups. Urinary LXA(4), 15-epi-LXA(4) and leukotriene E(4) (LTE(4) ) were quantified using enzyme immunoassay after separating these compounds using high-performance liquid chromatography.

RESULTS

The urinary LXA(4) concentration was significantly lower than the 15-epi-LXA(4) concentration in the asthmatic subjects. The AIA group showed significantly lower urinary 15-epi-LXA(4) (P < 0.01) and higher urinary LTE(4) concentrations (P < 0.05) than the ATA group. Comparison of 15-epi-LXA(4) concentrations between the severe asthmatic and non-severe asthmatic subjects in the AIA and ATA groups revealed that the decreased 15-epi-LXA(4) concentration may be related to aspirin intolerance, but not asthma severity. Receiver operator characteristic curves demonstrated that the concentration ratio of LTE(4) to 15-epi-LXA(4) was superior to 15-epi-LXA(4) concentration and LTE(4) concentration as a predictive factor for aspirin intolerance.

CONCLUSIONS AND CLINICAL RELEVANCE

We have demonstrated for the first time that urinary 15-epi-LXA(4) concentration is significantly higher than LXA(4) concentration in both the AIA and ATA groups. 15-Epi-LXA(4) concentration was significantly lower in the AIA group with an increased urinary LTE(4) concentration than in the ATA group. An imbalance between proinflammatory cysteinyl-leukotrienes and anti-inflammatory 15-epi-LXA(4) may be involved in AIA pathogenesis.

NSAIDs, Mitochondria and Calcium Signaling: Special Focus on Aspirin/Salicylates

Aspirin (acetylsalicylic acid) is a well-known nonsteroidal anti-inflammatory drug (NSAID) that has long been used as an anti-pyretic and analgesic drug. Recently, much attention has been paid to the chemopreventive and apoptosis-inducing effects of NSAIDs in cancer cells. These effects have been thought to be primarily attributed to the inhibition of cyclooxygenase activity and prostaglandin synthesis. However, recent studies have demonstrated unequivocally that certain NSAIDs, including aspirin and its metabolite salicylic acid, exert their anti-inflammatory and chemopreventive effects independently of cyclooxygenase activity and prostaglandin synthesis inhibition. It is becoming increasingly evident that two potential common targets of NSAIDs are mitochondria and the Ca²⁺ signaling pathway. In this review, we provide an overview of the current knowledge regarding the roles of mitochondria and Ca²⁺ in the apoptosis-inducing effects as well as some side effects of aspirin, salicylates and other NSAIDs, and introducing the emerging role of L-type Ca²⁺ channels, a new Ca²⁺ entry pathway in non-excitable cells that is up-regulated in human cancer cells.

Profile of eicosanoid generation in aspirin-intolerant asthma and anaphylaxis assessed by new biomarkers

BACKGROUND

It has recently demonstrated that a free radical-mediated pathway generates prostaglandins (PGs) and the corresponding prostaglandin enantiomers (ent-PGs). Aspirin-intolerant asthma and anaphylaxis accompany PGD(2) overproduction, possibly associated with mast cell activation via the COX pathway. However, free radical-mediated PG generation in the pathophysiology of these diseases, which can be demonstrated by measuring urinary ent-PGF(2)alpha, has not been reported.

OBJECTIVES

To evaluate the characteristic profile of eicosanoid generation via the COX and/or free radical-mediated pathway underlying aspirin-intolerant asthma and anaphylaxis.

METHODS

A comparative group analysis consisted of asthma (n = 17) and anaphylaxis (n = 8, none with aspirin-induced anaphylaxis) cases. Urinary eicosanoid concentrations were quantified as follows: 2,3-dinor-9alpha,11beta-PGF(2) by gas chromatography-mass spectrometry; leukotriene E(4), 9alpha,11beta-PGF(2), and PGs by enzyme immunoassay.

RESULTS

2,3-Dinor-9alpha,11beta-PGF(2) is a more predominant PGD(2) metabolite in urine than 9alpha,11beta-PGF(2). At baseline, the aspirin-intolerant asthma group (n = 10) had significantly higher leukotriene E(4) and lower PGE(2) concentrations in urine than the aspirin-tolerant asthma group. During the reaction, the urinary concentrations of leukotriene E(4) and PGD(2) metabolites correlatively increased, but with markedly different patterns of the mediator release, in the aspirin-intolerant asthma group and the anaphylaxis group, respectively. The urinary PGD(2) metabolites and primary PGs were significantly decreased in the aspirin-tolerant asthma group. Urinary ent-PGF(2)alpha concentrations were significantly increased in the anaphylaxis group but not the aspirin-intolerant asthma group.

CONCLUSIONS

When assessed by urinary 2,3-dinor-9alpha,11beta-PGF(2), PGD(2) overproduction during aspirin-intolerant bronchoconstriction was clearly identified, regardless of COX inhibition. It is evident that free radical-mediated PG generation is involved in the pathophysiology of anaphylaxis.

L-type Ca2+ channels: a new player in the regulation of Ca2+ signaling, cell activation and cell survival in immune cells

Ca(2+) is a highly versatile intracellular second messenger in many cell types, and regulates many complicated cellular processes, including cell activation, proliferation and apoptosis. Influx of Ca(2+) from the extracellular fluid is required for sustained elevation of the cytosolic Ca(2+) concentration and full activation of Ca(2+)-dependent processes. It is widely accepted that Ca(2+) release-activated Ca(2+) channels are the major routes of Ca(2+) influx in electrically non-excitable cells, including hematopoietic cells, whereas voltage-gated Ca(2+) channels such as L-type Ca(2+) channels (LTCCs) serve as the principal routes of Ca(2+) entry into electrically excitable cells such as neurons and myocytes. However, recent pharmacological and molecular genetic studies have revealed the existence of functional LTCCs and/or LTCC-like channels in a variety of immune cells including mast cells. In this article, we review recent advances in our understanding of Ca(2+) signaling in immune cells with a special interest in mast cells. We highlight roles for LTCCs in antigen receptor-mediated mast cell activation and survival.

Analysis of the mechanism for the development of allergic skin inflammation and the application for its treatment: aspirin modulation of IgE-dependent mast cell activation: role of aspirin-induced exacerbation of immediate allergy

Aspirin (acetylsalicylic acid) is a well-known nonsteroidal anti-inflammatory drug that can potentiate some acute allergies and causes adverse immunological reactions collectively referred to as aspirin intolerance, a disorder that induces urticaria, asthma, and anaphylaxis in response to oral administration of the drug. Aspirin also potentiates some acute allergies such as food-dependent exercise-induced anaphylaxis (FDEIA), a food allergy induced by physical exercise. The anti-inflammatory actions as well as the adverse immunological effects have been thought to be primarily due to inhibition of cyclooxygenase activity. However, a growing body of evidence suggests that mechanisms unrelated to inhibition of prostaglandin synthesis are involved. One key feature of aspirin intolerance is the overproductions of cysteinyl leukotrienes (LTs), in which mast cells have been implicated to play a role. In this review, we provide an overview of our current knowledge about the regulatory mechanisms of LTC(4) secretion in mast cells and its modulation by aspirin, with a special emphasis on the role of Ca(2+) signals. We also introduced our recent findings that mast cells express dihydropyridine-sensitive L-type Ca(2+) channels (LTCCs) and that Ca(2+) channels of this kind mediate aspirin modulation of LTC(4) secretion in mast cells.

Association of TNF-alpha promoter polymorphisms with aspirin-induced urticaria

OBJECTIVE

Although the pathogenesis of aspirin-induced urticaria (AIU) is not fully understood, mast cell activation has been noted in patients with AIU. Tumour necrosis factor (TNF)-alpha, a potent pro-inflammatory cytokine, is released by human skin mast cells and other inflammatory cells in patients with urticaria. To investigate the role of TNF-alpha promoter polymorphisms in the development of AIU, we performed an association study of TNF-alpha promoter polymorphisms with AIU phenotype.

METHODS

Two hundred thirty-nine patients with AIU consisting of 120 patients with aspirin intolerant chronic urticaria (AICU) and 119 with aspirin-intolerant acute urticaria (AIAU), and 524 normal controls were enrolled. AIU was confirmed by oral aspirin challenge test. Five SNPs in the TNF-alpha gene (-1031T>C, -863C>A, -857C>T, -308G>A, -238G>A) were genotyped by a single-base extension method. Haplotype analyses were done.

RESULTS

The genotype frequencies of TNF-1031T>C and TNF-863C>A were significantly higher in the AIU patients than in the normal controls in both co-dominant (P = 0.014, P = 0.007) and dominant (P = 0.007, P = 0.004) models. The frequency of TNF-ht2[CACGG] containing a genotype in the AIU group was significantly higher in the normal controls with both co-dominant (P = 0.004, Pc = 0.02) and dominant models (P = 0.002, Pc = 0.01).

CONCLUSIONS

These findings suggest that the two promoter polymorphisms of TNF-alpha at -1031T>C and -863C>A may contribute to the development of AIU.

[A cyclooxygenase-2 selective inhibitor worsens respiratory function and enhances mast cell activity in ovalbumin-sensitized mice]

BACKGROUND

Cyclooxygenase (COX)-2 activity has been said to have a protective effect in asthmatic patients as a result of prostaglandin E(2) production. In order to elucidate the mechanisms involved, we evaluated the impact of selective inhibition of COX-2 with rofecoxib during ovalbumin challenge, assessing mast cell activity and airway response in a murine model of asthma.

MATERIAL AND METHODS

Mice were sensitized to ovalbumin (10 microg injected intraperitoneally) and further challenged with 0.5% intranasal ovalbumin. Half the sensitized animals were treated orally with rofecoxib (15 mg/kg/d during the challenge phase). Lung function was measured by whole body plethysmography before and after exposure to ovalbumin. The severity of airway inflammation was evaluated by means of a scoring system. Finally, the serum level of mouse mast cell protease-1 was determined as an indicator of mucosal mast cell activity.

RESULTS

Sensitized mice treated with rofecoxib exhibited 2.4-fold greater airway hyperresponsiveness than did vehicle-treated mice at a methacholine concentration of 100mg/ml. A clear trend toward worsening airway inflammation in the presence of rofecoxib was observed, although the difference between rofecoxib-treated and vehicle-treated animals was not significant. These changes were accompanied by a significant increase in mucosal mast cell activity.

CONCLUSIONS

Selective pharmacological inhibition of COX-2 during the challenge phase worsens airway function in the ovalbumin -induced murine model of acute asthma. We suggest that this effect might be at least partially explained by the increase in airway mast cell activity.

Aspirin and salicylates modulate IgE-mediated leukotriene secretion in mast cells through a dihydropyridine receptor-mediated Ca(2+) influx

Aspirin is a well-known nonsteroidal anti-inflammatory drug (NSAID) that may potentiate some acute allergies and causes adverse immunological reactions collectively referred to as aspirin intolerance. Aspirin intolerance is accompanied by increased leukotriene (LT) synthesis, and high levels of serum IgE are a risk factor for NSAID sensitivity. Here we demonstrate that aspirin modulates LTC(4) secretion in mast cells. Therapeutic levels of aspirin and salicylates (<or=0.3 mM, i.e., the concentrations observed in vivo in the use of antipyretic analgesic) increased IgE-mediated LTC(4) secretion. Aspirin-induced stimulation was accompanied by increased Ser-505 phosphorylation of cytosolic phospholipase A(2), which occurred independently of extracellular signal-regulated protein kinase-1/2 and p38 mitogen-activated protein kinase pathways. Aspirin also increased IgE-mediated Ca(2+) influx, whereas aspirin at concentrations of >or=0.3 mM dose-dependently reduced Ca(2+) store emptying and Ca(2+) release-activated Ca(2+) channel activation. Instead, aspirin facilitated a dihydropyridine receptor-mediated Ca(2+) influx, resulting in increased LTC(4) secretion. This novel action of aspirin may play roles in exacerbation of immediate allergy and aspirin intolerance.

PGE suppresses excessive anti-IgE induced cysteinyl leucotrienes production in mast cells of patients with aspirin exacerbated respiratory disease

BACKGROUND

Aspirin causes bronchospasm in patients with aspirin exacerbated respiratory disease (AERD). The contribution of mast cells to the increased cysteinyl-leucotrienes (cys-LTs) detected in AERD patients is however not defined.

AIMS OF THE STUDY

Effects of prostaglandin (PG) E(2) and inhibitors of cyclooxygenase (COX) and lipoxygenase (LO) pathways on mediator release from cultured mast cells of normal subjects, aspirin tolerant asthma (ATA) and AERD patients were compared to better define the role of mast cells in AERD.

METHODS

Mast cells were cultured from peripheral blood progenitors and were activated by anti-IgE. Histamine, PGD(2) and cys-LTs released were then determined.

RESULTS

Basal release of all three mediators was similar in all subjects. Although the release of all three mediators was increased by anti-IgE, mast cells from AERD patients produced significantly more cys-LTs (6.9 +/- 2.0 ng/10(6) cells) than normal and ATA subjects (2.3 +/- 0.8 and 1.7 +/- 0.5 ng/10(6) cells, respectively). While COX and LO pathway inhibitors did not affect anti-IgE induced histamine release, they significantly suppressed the production of PGD(2) and cys-LTs, respectively, in all patients. PGE(2) significantly enhanced anti-IgE induced histamine and PGD(2) release from mast cells of normal subjects but not those of ATA and AERD patients. In contrast, PGE(2) suppressed only anti-IgE induced cys-LTs release from mast cells of AERD patients.

CONCLUSION

We speculate that overproduction of cys-LTs is unique to mast cells of AERD patients and is particularly sensitive to suppression by PGE(2). Consequently reduction of PGE(2) production by aspirin removes this endogenous control of cys-LTs overproduction, resulting in asthma attack.

Aspirin induces the production of the inflammatory mediator 8-epi-PGF in mast cells

Recently it has been shown that mast cells, through release of their pro-inflammatory mediators, are involved in aspirin attacks in aspirin-sensitive patients. To date, little information is available concerning 8-isoprostane (8-epi-prostaglandin F) production by mast cells. Therefore, we examined whether exposure of mast cells to aspirin can lead to isoprostane production. In this study we show that in mast cells, IgE and antigen stimulates an intracellular oxidative burst inducing H(2)O(2) and 8-epi-PGF production. Moreover, we show that exposure of mast cells to aspirin directly induces the production of 8-epi-PGF. Our study suggests that production of 8-epi-PGF by mast cells could contribute to the inflammatory response in e.g. aspirin-sensitive asthma patients.