Emerging Hop Japanese Pollinosis in Asia

Hop Japanese (Hop J) pollen has been considered one of the major causative pollen allergens in Far East Asia in the autumn season. The sensitization rate, pollen count, and allergenicity of Hop J pollens are increasing in this region because of increased air pollution and global warming. However, commercial skin test agents for the diagnosis and allergen extracts for the allergen immunotherapy are not available. This review summarizes recent data on clinical impact of Hop J pollinosis in order to facilitate the development of diagnostic and therapeutic agents for this region.

Down-regulated surfactant protein B in obese asthmatics

BACKGROUND

Obesity is a common comorbid condition in adult asthmatics and known as a feature of asthma severity. However, the molecular mechanism under obesity-induced inflammation has not yet been fully understood.

OBJECTIVE

Considering the essential role of hydrophobic surfactant protein B (SP-B) in lung function, SP-B was targeted to examine its involvement in the development of obesity-induced airway inflammation in asthmatics.

METHODS

The aim was to examine an alteration in circulating SP-B according to obesity in adult asthmatics, 129 asthmatics were enrolled and classified into 3 groups (obese, overweight and normal-weight groups) according to body mass index (BMI). Circulating SP-B levels were determined by enzyme-linked immunosorbent assay. Four single nucleotide polymorphisms of SFTPB gene were genotyped. Serum ceramide levels were measured by liquid chromatography-tandem mass spectrometry.

RESULTS

Significantly lower serum SP-B levels were noted in the obese group than in the overweight or normal-weight group (p = .002). The serum SP-B level was significantly correlated with serum levels of C18:0 ceramide and transforming growth factor beta 1 as well as BMI (r = -0.200; r = -0.215; r = -0.332, p < .050 for all). An inverse correlation was noted between serum SP-B and fractional exhaled nitric oxide levels in female asthmatics (r = -0.287, p = .009). Genetic predisposition of the SFTPB gene at 9306 A>G to the obese and overweight groups was noted.

CONCLUSION

Obesity altered ceramide metabolism leading to pulmonary surfactant dysfunction and impaired resolution of airway inflammation, finally contributing to the phenotypes of obese asthmatics.

The burden of symptomatic patients with chronic spontaneous urticaria: a real-world study in Korea

BACKGROUND/AIMS

Chronic spontaneous urticaria (CSU) poses a considerable burden both on the quality of life (QoL) of individual patients and on healthcare systems. Real‑world data evaluating the disease burden of CSU are limited in this country. This study evaluated the disease burden and healthcare resource utilization (HRU) among symptomatic CSU patients.

METHODS

This multicenter, noninterventional, retrospective, and cross-sectional study assessed CSU patients symptomatic for more than 6 months despite step-wise H1-antihistamine medications. Primary outcomes included Urticaria Activity Score over 7 days (UAS7) and Chronic Urticaria QoL scale (CU-QoL). Secondary outcomes included EuroQol 5-Dimension 5-Level (EQ-5D-5L), Dermatology Life Quality Index (DLQI), association of disease activity with QoL, medications used for the past 6 months, and HRU.

RESULTS

Five hundred patients with CSU were enrolled. Mean disease duration was 3.7 years. Based on UAS7, 22.2% of patients were in well-controlled status and 31.2%, 28.4%, and 18.2% of them had mild, moderate, and severe disease, respectively. Mean CU-QoL and DLQI scores were 57.5 ± 29.7 and 10.2 ± 7.6, respectively, while the EQ-5D-5L utility score was 0.8 ± 0.2. H1-antihistamines were prescribed to 95% of patients, while omalizumab was prescribed to 33% of patients. Most patients (98%) had outpatient visits in the past 6 months. Negative correlations were noted between UAS7 and CU-QoL, EQ-5D-5L, EQ-5D-5L visual analog scale scores, but a positive correlation was noted with DLQI score (p < 0.001 for all). The number of outpatient department visits increased with disease activity (p = 0.001).

CONCLUSION

CSU affects QoL, leading to increased HRU, particularly in patients with severe disease.

Extracellular Traps: A Novel Therapeutic Target for Severe Asthma

Asthma is a complicated disease defined by a combination of clinical symptoms and physiological characteristics. Typically, asthma is diagnosed by the presence of episodic cough, wheezing, or dyspnea triggered by variable environmental factors (allergens and respiratory infections), and reversible airflow obstruction. To date, the majority of asthmatic patients have been adequately controlled by anti-inflammatory/bronchodilating agents, but those with severe asthma (SA) have not been sufficiently controlled by high-dose inhaled corticosteroids-long-acting beta-agonists plus additional controllers including leukotriene modifiers. Accordingly, these uncontrolled patients provoke a special issue, because they consume high healthcare resources, requiring innovative precision medicine solutions. Recently, phenotyping based on biomarkers of airway inflammation has led to elucidating the pathophysiological mechanism of SA, where emerging evidence has highlighted the significance of eosinophil or neutrophil extracellular traps contributing to the development of SA. Here, we aimed to provide current findings about extracellular traps as a novel therapeutic target for asthma to address medical unmet needs.

Effectiveness of Maintenance and Reliever Therapy Using Inhaled Corticosteroid–Formoterol in Asthmatics

BACKGROUND

Real-world evidence on the effectiveness of maintenance and reliever therapy (MART) using inhaled corticosteroids plus long-acting beta-2 agonist (ICS-LABA) is sparse.

OBJECTIVE

This study aimed to evaluate the clinical effectiveness of MART (ICS-formoterol) by comparing its effectiveness with that of ICS-LABA plus as-needed short-acting beta-2 agonist (SABA) in adult asthmatics.

METHODS

We retrospectively retrieved data from the medical records of the Ajou University Medical Center, Korea, to compare clinical outcomes between patients treated with MART (the MART group) and those treated with ICS-LABA plus SABA (the non-MART group). Propensity score matching was performed and hazard ratios (HRs) with 95% confidence intervals were calculated using the Cox proportional hazards model. Severe asthma exacerbation (SAEx) was the primary end point, and asthma exacerbation (AEx), hospitalization, and pneumonia were secondary end points. Corticosteroid requirement was also analyzed.

RESULTS

After propensity score matching, the MART and the non-MART groups included 231 and 512 adult asthmatics, respectively. The risk of SAEx and AEx was significantly lower in the MART group than in the non-MART group (HR [95% CI] 0.39 [0.18-0.77] and 0.61 [0.37-0.99], respectively). There was no significant difference in hospitalization and pneumonia risk between the 2 groups (HR [95% CI] 0.88 [0.55-1.37] and 0.63 [0.03-4.51], respectively). Corticosteroid requirements were lower in the MART group than in the non-MART group (median [interquartile range], 190.0 [97.9-420.0] and 411.0 [143.0-833.0] mg/person-year, respectively; P < .01).

CONCLUSIONS

The MART strategy of ICS-formoterol was associated with lower risk of AEx and reduced corticosteroid requirement.

Mono-n-butyl phthalate regulates nuclear factor erythroid 2-related factor 2 and nuclear factor kappa B pathway in an ovalbumin-induced asthma mouse model

Recent studies have emphasized the role of endocrine-disrupting chemicals in asthma development, especially in eosinophilic asthma. However, the exact mechanism was unknown. Among all the endocrine-disrupting chemicals, mono-n-butyl phthalate (MnBP) was a chemical that was most frequently detected in human urine. Our study was performed with the aim of investigating the harmful effects of MnBP on airway epithelial cells (AECs), T cells, and eosinophils by using eosinophilic asthma mouse models. Mice that received OVA with MnBP had higher levels of airway hyperresponsiveness, total and eosinophil cell counts, as well as T cell proliferation and T helper 2 cytokine release than those which only received OVA. Moreover, MnBP contributed to directly enhancing the eosinophilic activation which was shown in. Long-term exposure MnBP activated AECs through the nuclear factor kappa B (NF-kB) pathway, decreased nuclear factor erythroid 2-related factor 2 (Nrf2) expression, and increased interleukin-33 expression. Additionally, MnBP can induce human eosinophil activation to release eosinophil extracellular traps (EETs). Taken together, our study suggested the roles of MnBP exposure increase the risk of asthma development and severity. Furthermore, vitamin E treatment (anti-inflammatory and antioxidant effects) can reduce MnBP-induced harmful effects through inhibiting EETs, restoring Nrf2, and suppressing the NF-kB pathway.

Immunoregulatory effects of Lactococcus lactis-derived extracellular vesicles in allergic asthma

Background

Probiotics have been shown to prevent various allergic diseases by producing extracellular vesicles (EVs). However, the role of EVs in allergic asthma has not yet been completely determined.

Methods

Gut microbial composition, mainly genera related to probiotics, was investigated in allergic asthmatic mice. Moreover, EVs were isolated from Lactococcus lactis (L. lactis, a selected bacterium) and EV proteins were identified by peptide mass fingerprinting. EV functions in immune responses were evaluated in vivo or ex vivo. Furthermore, the levels of specific IgG antibodies (an alternative marker for EV quantification) to L. lactis‐EVs were measured by ELISA in the sera of 27 asthmatic patients and 26 healthy controls.

Results

Allergic asthmatic mice showed a lower proportion of Lactococcus compared to healthy mice. L. lactis was cultured and its EVs abundantly contained pyruvate kinase. When allergic asthmatic mice were intranasally treated with EVs, airway hyperresponsiveness, eosinophil number, cytokine secretion, and mucus production were significantly decreased. Moreover, L. lactis‐EV treatment shifted immune responses from Th2 to Th1 by stimulating dendritic cells to produce IL‐12. In addition, significantly lower levels of serum specific IgG4 (but not IgG1) to L. lactis‐EVs were noted in asthmatic patients than in healthy controls. A positive correlation between the levels of EV‐specific IgG4 and FEV₁ (%), but a negative correlation between the levels of EV‐specific IgG4 and IL‐13 were observed.

Conclusion

These findings suggest that L. lactis‐EVs may have immune‐regulating effects on airway inflammation mediated by dendritic cell activation, providing a potential benefit for allergic asthma.

Increased serum free IgE levels in patients with chronic spontaneous urticaria (CSU)

Background

IgE bound on the surface of mast cells contributes to the pathogenesis of chronic spontaneous urticaria (CSU). Atopy is a predisposing factor for CSU, where omalizumab is a widely used monoclonal antibody to control urticaria symptoms via capturing serum free IgE. However, the role of serum free IgE is not clarified in CSU. The present study evaluated the clinical relevance of serum free IgE in patients with CSU.

Methods

Eighty-eight patients with CSU and 76 healthy controls (HCs) were enrolled in this study. Serum total and Dermatophagoides pteronyssinus (Der p)-specific IgE levels were measured by ImmunoCAPs. The serum free IgE levels were measured by ELISA using a novel IgETRAP, and their associations with clinical parameters, including urticaria activity score (UAS), were evaluated. Changes in serum free and total IgE levels after omalizumab treatment were observed in 23 CSU patients in comparison between responders (≥50% reduction in UAS) and non-responders (<50% reduction).

Results

Significantly higher serum free/total IgE levels were noted in CSU patients than in HCs with a positive correlation between the 2 values (rho = 0.87, P < 0.001). Among CSU patients, atopics had significantly higher serum free IgE levels than non-atopics, while no associations were noted with UAS, urticaria duration, or the results of serum ANA or autologous serum skin tests. In addition, there were no significant changes in serum free IgE levels during 12 months of omalizumab treatment. No significant differences were noted in serum free/total IgE levels or clinical parameters between responders and non-responders, while responders have higher serum Der p-specific IgE level and its ratio to serum free/total IgE level than non-responders (P < 0.05, respectively).

Conclusions

These findings suggest that increased serum free IgE may be involved in the development of CSU by activating mast cells, especially in atopics. High Der p-specific IgE level and its ratio to serum free IgE level may be a potential biomarker for predicting favorable responses to omalizumab in CSU.

Role of Thymus and Activation-Regulated Chemokine in Allergic Asthma

Background

Objective

Methods

Results

Conclusion

Serum Amyloid A1: A Biomarker for Neutrophilic Airway Inflammation in Adult Asthmatic Patients

Purpose

We evaluated the role of serum amyloid A1 (SAA1) in the pathogenesis of airway inflammation according to the phenotype of asthma.

Methods

One hundred twenty-two asthmatic patients and 60 healthy control subjects (HCs) were enrolled to measure SAA1 levels. The production of SAA1 from airway epithelial cells (AECs) and its effects on macrophages and neutrophils were investigated in vitro and in vivo.

Results

The SAA1 levels were significantly higher in sera of asthmatic patients than in those of HCs (P = 0.014); among asthmatics, patients with neutrophilic asthma (NA) showed significantly higher SAA1 levels than those with non-NA (P < 0.001). In vitro, polyinosinic:polycytidylic acid (Poly I-C) treatment markedly enhanced the production of SAA1 from AECs, which was further augmented by neutrophils; SAA1 could induce the production of interleukin (IL)-6, IL-8, and S100 calcium-binding protein A9 from AECs. Additionally, SAA1 activated neutrophils and macrophages isolated from peripheral blood of asthmatics, releasing neutrophil extracellular traps (NETs) and secreting proinflammatory cytokines presenting M1 phenotype, respectively. In ovalbumin-induced asthma mice, Poly I-C treatment significantly increased SAA1 levels as well as IL-17A/interferon-gamma/IL-33 levels in bronchoalveolar lavage fluid (BALF), leading to airway hyperresponsiveness and inflammation. The highest levels of SAA1 and neutrophilia were noted in the BALF and sera of the NA mouse model, followed by the mixed granulocytic asthma (MA) model. Especially, SAA1 induced IL-17/retinoic acid receptor-related orphan receptor γt expression from activated CD4+ T lymphocytes in asthmatic mice.

Conclusions

The results show that SAA1 could induce neutrophilic airway inflammation by activating neutrophils along with NET formation, M1 macrophages, and Th2/Th17 predominant cells, contributing to the phenotype of NA or MA.

The Role of Di(2-Ethylhexyl) Phthalate as an Exacerbating Factor in Chronic Spontaneous Urticaria

Phthalates are one of the most commonly used endocrine disruptors and have been considered a risk factor for respiratory disease including asthma. However, it is not yet known how they are related to urticaria. We investigated the association between phthalate exposure and urticaria in 10 healthy controls and 20 adult patients with active urticaria. The urinary levels of mono-n-butyl phthalate (MnBP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), mono-(2-ethyl-5-oxohexyl) phthalate, and mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) were measured by using high performance liquid chromatography tandem mass spectrometry, and mast cell releasability was determined after phthalate treatment. The levels of phthalate metabolites, especially di-ethylhexyl phthalate (DEHP), are significantly increased in the urine of patients with urticaria compared to the healthy controls. The release of β-hexosaminidase in human mast cells is more significantly increased by MnBP, mono-benzyl phthalate, MEHHP, and MECPP compared to the negative controls; interestingly, the highest secretion of β-hexosaminidase is observed after the lowest stimulation of MECPP. Phthalates, including DEHP, may act as aggravating factors for chronic spontaneous urticaria and can be used as potential therapeutic targets in future studies.

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.

Persistent Eosinophilic Inflammation in Adult Asthmatics with High Serum and Urine Levels of Leukotriene E4

Background

Cysteinyl leukotrienes (CysLTs) are key mediators for bronchoconstriction, eosinophil recruitment and mucus production in the airways of asthmatic patients. To better understand the role of CysLTs in different asthma phenotypes, we compared the levels of arachidonic acid metabolites in relation to asthma control status and phenotypes in adult asthmatics on regular anti-asthma medications.

Methods

A total of 137 adult asthmatics (47 with aspirin-exacerbated respiratory disease [AERD] and 90 asthmatics with aspirin-tolerant asthma [ATA]) and 20 healthy controls were enrolled. Arachidonic acid metabolites in serum and urine were analyzed using LC-MS/MS methods, and clinical data, including asthma control status, exhaled NO (FeNO) and lung function tests, were collected.

Results

Urine LTE₄ levels were significantly higher in AERD patients on inhaled corticosteroid-long-acting β₂- agonist plus leukotriene receptor antagonist (LTRA) treatment than in ATA patients (P=0.001). No differences were found in the serum or urine levels of 15-HETE, TXB_2, or PGF_2α. High serum LTE₄ levels were associated with lower FEV1% and uncontrolled status in AERD patients (P=0.006 and P=0.002, respectively), but not in ATA patients. Multivariate analysis demonstrated that blood eosinophil counts, FeNO levels and aspirin hypersensitivity were significant factors affecting urine LTE₄ levels.

Conclusion

Despite LTRA treatment in AERD, the LTE₄ levels remained high and showed close associations with blood eosinophilia, high FeNO levels and impaired disease control. Our real-world evidence indicates that control of asthma is not fully achieved by blocking the CysLT pathway with LTRA. Thus, introduction of treatment modalities targeting eosinophilia could be a better option for patients with high CysLTs.

Recent update on the management of anaphylaxis

Anaphylaxis is a life-threatening systemic allergic reaction presenting various clinical manifestations. Its prevalence has increased in almost all age groups and both sexes. Food, venom, and drugs are major causes in both children and adults; a higher prevalence of food-induced anaphylaxis is noted in children, while a higher prevalence of drug-induced anaphylaxis is noted in adults. The pathogenic mechanism is mediated by immunologic and nonimmunologic mechanisms, where mast cells and basophils are key cells that release mediators. A diagnosis of anaphylaxis is mainly based on clinical symptoms and physical findings; however, an increased serum tryptase level is a useful biomarker. Epinephrine is the first-line drug to treat acute symptoms, and an epinephrine auto-injector should be prescribed for each patient. Antihistamines and systemic corticosteroids are used to relieve symptoms. This review updates current issues in the management of anaphylaxis as well as the new guidelines for proper diagnosis and treatment.

Effect of TGF-β1 on eosinophils to induce cysteinyl leukotriene E4 production in aspirin-exacerbated respiratory disease

Cysteinyl leukotriene (cysLT) overproduction and eosinophil activation are hallmarks of aspirin-exacerbated respiratory disease (AERD). However, pathogenic mechanisms of AERD remain to be clarified. Here, we aimed to find the significance of transforming growth factor beta 1 (TGF-β1) in association with cysteinyl leukotriene E4 (LTE4) production, leading to eosinophil degranulation. To evaluate levels of serum TGF-β1, first cohort enrolled AERD (n = 336), ATA (n = 442) patients and healthy control subjects (HCs, n = 253). In addition, second cohort recruited AERD (n = 34) and ATA (n = 25) patients to investigate a relation between levels of serum TGF-β1 and urinary LTE4. The function of TGF-β1 in LTE4 production was further demonstrated by ex vivo (human peripheral eosinophils) or in vivo (BALB/c mice) experiment. As a result, the levels of serum TGF-β1 were significantly higher in AERD patients than in ATA patients or HCs (P = .001; respectively). Moreover, levels of serum TGF-β1 and urinary LTE4 had a positive correlation (r = 0.273, P = .037). In the presence of TGF-β1, leukotriene C4 synthase (LTC4S) expression was enhanced in peripheral eosinophils to produce LTE4, which sequentially induced eosinophil degranulation via the p38 pathway. When mice were treated with TGF-β1, significantly induced eosinophilia with increased LTE4 production in the lung tissues were noted. These findings suggest that higher levels of TGF-β1 in AERD patients may contribute to LTE4 production via enhancing LTC4S expression which induces eosinophil degranulation, accelerating airway inflammation.

Contribution of dipeptidyl peptidase 10 to airway dysfunction in patients with NSAID-exacerbated respiratory disease

BACKGROUND

Genetic variants of dipeptidyl peptidase 10 (DPP10) have been suggested to contribute to the development of NSAID-exacerbated respiratory disease (NERD). However, the mechanisms of how DPP10 contributes to NERD phenotypes remain unclear.

OBJECTIVE

To demonstrate the exact role of DPP10 in the pathogenesis of NERD.

METHODS

Patients with NERD (n = 110), those with aspirin-tolerant asthma (ATA, n = 130) and healthy control subjects (HCs, n = 80) were enrolled. Clinical characteristics were analysed according to the serum DPP10 levels in both NERD and ATA groups. The function of DPP10 in airway inflammation and remodelling was investigated with in vitro, ex vivo and in vivo experiments.

RESULTS

NERD patients had higher levels of serum DPP10 and TGF-β1 with lower FEV₁ than ATA patients or HCs (p < .05 for each). NERD patients with higher DPP10 levels had higher TGF-β1, but lower FEV₁ (p < .05 for all), whilst no differences were noted in ATA patients. Moreover, the seum DPP10 levels had a positive correlation with TGF-β1 (r = 0.384, p < .001), but a negative correlation with FEV₁ (r = -0.230, p = .016) in NERD patients. In in vitro studies, expression of DPP10 in airway epithelial cells was enhanced by TGF-β1 treatments. Furthermore, DPP10 was found to be produced from immune cells and this molecule induced the ERK phosphorylation in airway epithelial cells, which was suppressed by anti-DPP10 treatment. In asthmatic mouse models, increased levels of DPP10 in the serum and TGF-β1 in the bronchoalveolar lavage fluid were noted, which were suppressed by anti-DPP10 treatment. Moreover, anti-DPP10 treatment inhibited the ERK phosphorylation and extracellular matrix deposition in the lungs.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings suggest that increased production of DPP10 may contribute to TGF-β1-mediated airway dysfunction in NERD patients, where blockade of DPP10 may have potential benefits.

Update on latex allergy: New insights into an old problem

Despite the efforts made to mitigate the consequences of this disease, natural rubber latex allergy (NRLA) continues to be a global health problem and is still considered one of the main worries in the working environment in many countries throughout the world. Due to thousands of products containing latex, it is not surprising that the current statistics suggest that prevalence remains high among healthcare workers and susceptible patients. In developed countries, reduction in the prevalence of IgE-mediated allergy to latex proteins from gloves may lead to lax attention by health care personnel. On the other hand, this situation is different in developing countries where there is a lack of epidemiological data associated with a deficit in education and awareness of this issue. The aim of this review is to provide an update of the current knowledge and practical recommendations regarding NRLA by allergologists from different parts of the world with experience in this field.

Effect of omalizumab as add-on therapy to Quality of Life Questionnaire for Korean Asthmatics (KAQLQ) in Korean patients with severe persistent allergic asthma

BACKGROUND/AIMS

Omalizumab is the first biologic known to be effective in patients with severe allergic asthma.

METHODS

This study was conducted as a multicenter, single-group, open trial to evaluate the improvement in the quality of life with the additional administration of omalizumab for 24 weeks in Korean patients with severe persistent allergic asthma.

RESULTS

Of the 44 patients, 31.8% were men and the mean age was 49.8 ± 11.8 years. A score improvement of 0.5 points or more in the Quality of Life Questionnaire for Korean Asthmatics (KAQLQ) was noted in 50.0% (22/44) of the patinets. In the improved group, the baseline total immunoglobulin E (IgE) level and the amount of omalizumab used were higher, and the day and night asthma symptoms were more severe, compared to those in the non-improved group. According to the Global Evaluation of Treatment Effectiveness, favorable outcomes were found in 78.6% of patients. The Korean asthma control test (p < 0.005) and forced expiratory volume in 1 second % predicted (FEV1%; p < 0.01) improved significantly in patients who received omalizumab treatment, compared to that at week 0, and the total dose of rescue systemic corticosteroids significantly decreased (p < 0.05). The improved group on KAQLQ showed a significant improvement in FEV1% (p < 0.001).

CONCLUSION

Omalizumab can be considered a biological treatment for Korean patients with severe allergic asthma. It is recommended to consider omalizumab as add-on therapy in patients with high baseline total IgE levels and severe asthma symptoms.

S100A9 in adult asthmatic patients: a biomarker for neutrophilic asthma

The biomarkers and therapeutic targets of neutrophilic asthma (NA) are poorly understood. Although S100 calcium-binding protein A9 (S100A9) has been shown to correlate with neutrophil activation, its role in asthma pathogenesis has not been clarified. This study investigated the mechanism by which S100A9 is involved in neutrophil activation, neutrophil extracellular trap (NET)-induced airway inflammation, and macrophage polarization in NA. The S100A9 levels (by ELISA) in sera/culture supernatant of peripheral blood neutrophils (PBNs) and M0 macrophages from asthmatic patients were measured and compared to those of healthy controls (HCs). The function of S100A9 was evaluated using airway epithelial cells (AECs) and PBNs/M0 macrophages from asthmatic patients, as well as a mouse asthma model. The serum levels of S100A9 were higher in NA patients than in non-NA patients, and there was a positive correlation between serum S100A9 levels and sputum neutrophil counts (r = 0.340, P = 0.005). Asthmatic patients with higher S100A9 levels had lower PC20 methacholine values and a higher prevalence of severe asthma (SA) (P < .050). PBNs/M0 macrophages from SA released more S100A9 than those from non-SA patients. PBNs from asthmatic patients induced S100A9 production by AECs, which further activated AECs via the extracellular signal-regulated kinase (ERK) pathway, stimulated NET formation, and induced M1 macrophage polarization. Higher S100A9 levels in sera, bronchoalveolar lavage fluid, and lung tissues were observed in the mouse model of NA but not in the other mouse models. These results suggest that S100A9 is a potential serum biomarker and therapeutic target for NA.

Potential Metabolic Biomarkers in Adult Asthmatics

Asthma is the most common chronic airway inflammation, with multiple phenotypes caused by complicated interactions of genetic, epigenetic, and environmental factors. To date, various determinants have been suggested for asthma pathogenesis by a new technology termed omics, including genomics, transcriptomics, proteomics, and metabolomics. In particular, the systematic analysis of all metabolites in a biological system, such as carbohydrates, amino acids, and lipids, has helped identify a novel pathway related to complex diseases. These metabolites are involved in the regulation of hypermethylation, response to hypoxia, and immune reactions in the pathogenesis of asthma. Among them, lipid metabolism has been suggested to be related to lung dysfunction in mild-to-moderate asthma. Sphingolipid metabolites are an important mediator contributing to airway inflammation in obese asthma and aspirin-exacerbated respiratory disease. Although how these molecular variants impact the disease has not been completely determined, identification of new causative factors may possibly lead to more-personalized and precise pathway-specific approaches for better diagnosis and treatment of asthma. In this review, perspectives of metabolites related to asthma and clinical implications have been highlighted according to various phenotypes.

Pharmacogenomics of Hypersensitivity to Non-steroidal Anti-inflammatory Drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are extensively prescribed in daily clinical practice. NSAIDs are the main cause of drug hypersensitivity reactions all over the world. The inhibition of cyclooxygenase enzymes by NSAIDs can perpetuate arachidonic acid metabolism, shunting to the 5-lipoxygenase pathway and its downstream inflammatory process. Clinical phenotypes of NSAID hypersensitivity are diverse and can be classified into cross-reactive or selective responses. Efforts have been made to understand pathogenic mechanisms, in which, genetic and epigenetic backgrounds are implicated in various processes of NSAID-induced hypersensitivity reactions. Although there were some similarities among patients, several genetic polymorphisms are distinct in those exhibiting respiratory or cutaneous symptoms. Moreover, the expression levels, as well as the methylation status of genes related to immune responses were demonstrated to be involved in NSAID-induced hypersensitivity reactions. There is still a lack of data on delayed type reactions. Further studies with a larger sample size, which integrate different genetic pathways, can help overcome current limitations of gen etic/epigenetic studies, and provide valuable information on NSAID hypersensitivity reactions.