Type 2-high Asthma Research Articles

High-CBD Extract (CBD-X) in Asthma Management: Reducing Th2-Driven Cytokine Secretion and Neutrophil/Eosinophil Activity.

Asthma is a chronic inflammatory disorder of the airways affecting over 10% of the global population. It is characterized by airway inflammation, mucus hypersecretion, and bronchial hyperresponsiveness, driven predominantly by type 2 helper T cells (Th2) and type 2 innate lymphoid cells (ILC2s) in a subset of patients. However, a significant portion of asthmatic individuals present with "type 2-low" asthma that is often refractory to standard inhaled corticosteroid (ICS) therapy. Therefore, developing innovative therapeutic strategies has become essential. Recent studies have highlighted cannabidiol (CBD) as a promising anti-inflammatory agent capable of modulating immune responses. This study investigates the therapeutic potential of a high-CBD extract (CBD-X) in asthma. We evaluated the effects of CBD-X on cells involved in asthma pathogenesis using primary human Th2 cells, neutrophils, and asthma mouse model. Our findings indicate that CBD-X extract inhibits Th2 differentiation and reduces the secretion of IL-5 and IL-13, which are crucial cytokines in asthma. Additionally, CBD-X significantly reduces pro-inflammatory cytokines IL-8 and IL-6 in neutrophils and impairs their migration, a critical step in airway inflammation. In a murine asthma model, CBD-X administration led to marked downregulation of IgE and pro-asthmatic cytokines, along with reduced leukocyte, eosinophil, and neutrophil infiltration in lung tissues. These results suggest that CBD-X extract could offer a novel and complementary approach to managing both type 2-high and type 2-low asthma by targeting key inflammatory pathways and modulating immune cell behavior.

A partial loss-of-function variant in STAT6 protects against T2 asthma

BackgroundSignal Transducer and Activator of Transcription 6 (STAT6) is central to Type 2 (T2) inflammation and common non-coding variants at the STAT6 locus associate with various T2 inflammatory traits, including diseases, and its pathway is widely targeted in asthma treatment. ObjectiveTo test the association of a rare missense variant in STAT6, p.L406P, with T2 inflammatory traits, including the risk of asthma and allergic diseases, and to characterize its functional consequences in cell culture. MethodsWe tested association of p.L406P with plasma protein levels, white blood cell counts and the risk of asthma and allergic phenotypes. We tested significant associations in other cohorts using a burden test. The effects of p.L406P on STAT6 protein function were examined in cell lines and by comparing CD4+ T-cell responses from carriers and non-carriers of the variant. Resultsp.L406P associated with reduced plasma levels of STAT6 and IgE as well as with lower eosinophil and basophil counts in blood. It also protected against asthma, mostly driven by severe T2 high asthma. We showed that p.L406P led to lower IL-4-induced activation in luciferase reporter assays and lower levels of STAT6 in CD4+ T cells. We identified multiple genes with expression that was affected by the p.L406P genotype upon IL-4 treatment of CD4+ T cells; the effect was consistent with a weaker IL-4 response in carriers than non-carriers of p.L406P. ConclusionsWe report a partial loss-of-function variant in STAT6, resulting in dampened IL-4 responses and protection from T2 high asthma, implicating STAT6 as an attractive therapeutic target.

Bioinformatics analysis of G protein subunit gamma transduction protein 2-autophagy axis in CD11b+ dendritic cells as a potential regulator to skew airway neutrophilic inflammation in asthma endotypes.

Asthma is a heterogeneous inflammatory disease with two main clinical endotypes: type 2 (T2) high and low asthma. The plasticity and autophagy in dendritic cells (DCs) influence T helper (Th)2 or Th17 differentiation to regulate asthma endotypes. Enhanced autophagy in DCs fosters Th2 differentiation in allergic environments, while reduced autophagy favors Th17 cell differentiation in sensitized and infected environments. Autophagy regulation in DCs involves interaction with various pathways like G protein-coupled receptor (GPCR), mammalian target of rapamycin (mTOR), or phosphoinositide 3-kinase (PI3K) pathway. However, specific molecules within DCs influencing asthma endotypes remain unclear. Gene expression data series (GSE) 64896, 6858, 2276, and 55247 were obtained from gene expression omnibus (GEO) database. Differentially expressed genes (DEGs) between CD103+ and CD11b+ DCs after induction by ovalbumin (OVA) and lipopolysaccharide (LPS) were analyzed using GEO2R. DEGs were examined through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) analyses. The hub gene network was construct with STRING database and Cytoscape. Autophagy differences in DCs and the selected hub gene in GSE6858, GSE2276, and GSE55247 were evaluated using student t tests. Our analysis identified 635 upregulated and 360 downregulated genes in CD11b+ DCs, compared to CD103+ DCs. These DEGs were associated with "PI3K-AKT signaling pathway," "Ras signaling pathway," and so forth. Thirty-five hub genes were identified, in which G protein subunit gamma transduction protein 2 (Gngt2) in CD11b+ DCs exhibited a relatively specific increase in expression associated with autophagy defects under the induction environment similar to T2 low asthma model. No significant difference was found in lung Gngt2 expression between T2 high asthma model and control group. Our analysis suggested Gngt2 acted as an adapter molecule that inhibited autophagy, promoting Th17-mediated airway inflammation via the GPCR pathway in a T2 low asthma mice model. Targeting this pathway provides new asthma treatment strategies in preclinical research.

A single infusion of engineered long-lived and multifunctional T cells confers durable remission of asthma in mice.

Asthma, the most prevalent respiratory disease, affects more than 300 million people and causes more than 250,000 deaths annually. Type 2-high asthma is characterized by interleukin (IL)-5-driven eosinophilia, along with airway inflammation and remodeling caused by IL-4 and IL-13. Here we utilize IL-5 as the targeting domain and deplete BCOR and ZC3H12A to engineer long-lived chimeric antigen receptor (CAR) T cells that can eradicate eosinophils. We call these cells immortal-like and functional IL-5 CAR T cells (5TIF) cells. 5TIF cells were further modified to secrete an IL-4 mutein that blocks IL-4 and IL-13 signaling, designated as 5TIF4 cells. In asthma models, a single infusion of 5TIF4 cells in fully immunocompetent mice, without any conditioning regimen, led to sustained repression of lung inflammation and alleviation of asthmatic symptoms. These data show that asthma, a common chronic disease, can be pushed into long-term remission with a single dose of long-lived CAR T cells.

Effects of biological therapies on patients with Type-2 high asthma and comorbid obesity.

Over 20 million adults and 6 million children in the United States (US) have asthma, a chronic respiratory disease characterized by airway inflammation, bronchoconstriction, and mucus hypersecretion. Obesity, another highly prevalent disease in the US, is a major risk factor for asthma and a significant cause of diminished asthma control, increased submucosal eosinophilia, and reduced quality of life. A large subgroup of these patients experiences severe symptoms and recurrent exacerbations despite maximal dosage of standard asthma therapies. In the past two decades, the development of biological therapies has revolutionized the field and advanced our understanding of type 2 inflammatory biomarkers. However, patients with obesity and comorbid asthma are not principally considered in clinical trials of biologics. Large landmark cluster analyses of patients with asthma have consistently identified specific asthma phenotypes that associate with obesity but may be differentiated by age of asthma onset and inflammatory cell profiles in sputum. These patterns suggest that biologic processes driving asthma pathology are heterogenous among patients with obesity. The biological mechanisms driving pathology in patients with asthma and comorbid obesity are not well understood and likely multifactorial. Future research needs to be done to elicit the cellular and metabolic functions in the relationship of obesity and asthma to yield the best treatment options for this multiplex condition. In this review, we explore the key features of type 2 inflammation in asthma and discuss the effectiveness, safety profile, and research gaps regarding the currently approved biological therapies in asthma patients with obesity.

Pharmacologic Treatment of Type 2-High Severe Asthma

Asthma is a common and heterogeneous disease whose treatment has considerably changed over the last decades. While inhaled therapies based on inhaled corticosteroids and long acting β2 agonists are effective in controlling asthma in the majority of patients, about 5% of asthmatics poorly respond to inhaled steroids or inhaled steroids/long acting β2 agonists combinations. These patients are affected by “severe asthma”, which is associated with need of oral corticosteroids, progression of the disease, increased use of healthcare services, deterioration of quality of life, and a significant economic burden on society. Asthma is no longer considered a single disease, but a respiratory syndrome with complex biological network of distinct and interrelating inflammatory and remodeling pathways (endotypes) that are associated with different clinical manifestations (phenotypes) both in the lungs (asthma) and other organs (e.g. nose and skin). Severe asthma endotypes may be broadly regarded as Type 2-high and Type 2-low, a model that has become central to asthma management with the development of novel treatments for the Type 2-high endotypes. The hallmark feature of Type 2-high asthma is eosinophilic inflammation, often associated with increased serum IgE, increased exhaled nitric oxide (FeNO) and blood eosinophilia. The discovery of the main key drivers of Type 2-high inflammation (IgE, cytokines such as interleukin IL-5, -4 and -13) enabled the development of new biological agents directed towards specific molecular targets. These advances have shifted the existing paradigm “one drug fits all” to “patient-tailored” novel therapies. The monoclonal antibodies direct to IgE (omalizumab), IL-5 and IL-5 receptor (mepolizumab, benralizumab, reslizumab), and to the α chain of the IL-4 and IL-13 combined receptor (dupilumab), and more recently, to the thymic stromal lymphopoietin (tezepelumab) have been shown in both clinical trials and real-life studies to control symptoms, reduce asthma exacerbations and improve lung function in severe asthmatics not controlled by full inhalation therapies. More recently, the Single Inhaler Triple Therapy (SITT) containing inhaled steroids, long acting β2 agonists and muscarinic antagonists has been developed, slightly improving the effectiveness/safety of the inhalation therapy. This report aims to review available therapeutic opportunities for patients with severe asthma focusing on patients with Type 2-high severe asthma and how to position these new therapeutic alternatives in clinical practice.

Update on Inflammatory Biomarkers for Defining Asthma Phenotype.

Asthma is a chronic heterogeneous disease characterized by various symptoms and persistent airway inflammation, resulting in progressive lung function decline. Classifying asthma phenotypes/endotypes is crucial because the underlying mechanisms and long-term outcomes vary from patient to patient. Recent trials have identified several biomarkers for classifying asthma phenotypes/endotypes, and current treatments have been developed on the basis of these biomarkers. Conventional biomarkers, including immunoglobulin E, blood/sputum eosinophil counts, airway obstruction or reversibility, and fractional exhaled nitric oxide, are widely used to diagnose asthma. However, these markers have some limitations, necessitating the discovery of additional biomarkers. Therefore, this review summarizes recently suggested biomarkers for representing type 2-high (eosinophilic) vs. type 2-low (neutrophilic) asthma, non-steroidal anti-inflammatory drug-exacerbated respiratory disease, and severe asthma. Additionally, we discuss the potential benefits of these biomarkers in classifying specific phenotypes/endotypes and managing asthmatic patients.

Real-World Characteristics of Patients with Severe Asthma prior to Starting Dupilumab: The ProVENT Study

Introduction: Dupilumab is approved for the treatment of severe type 2 (T2) asthma; however, the characteristics of patients receiving dupilumab in routine clinical practice are incompletely understood. This study describes the characteristics of patients with severe asthma before dupilumab treatment in a real-world setting. Methods: This interim analysis of an ongoing real-life study of dupilumab assessed baseline characteristics of the first patient cohort enrolled in the ProVENT study. Results: A total of 99 patients (59% females) were analyzed (17% received another biologic before dupilumab treatment and 15% were on maintenance oral corticosteroid treatment). Adult-onset asthma (>18 years) and an allergic phenotype were documented in 58% and 48% of patients, respectively. Median (interquartile range) age was 54 (40–61) years; the median number of exacerbations in the last 24 months was 1 (0–3); median fractional exhaled nitric oxide (FeNO) value was 38 (23–64) ppb; and median blood eosinophils (bEOS) count was 184 (8–505) cells/µL. According to the United Kingdom Severe Asthma Registry classification, 53% of patients had T2 intermediate asthma (bEOS ≥150 cells/µL or FeNO ≥25 ppb), 17% had T2 high asthma (bEOS ≥150 cells/µL and FeNO ≥25 ppb), and 4% had T2 low asthma (bEOS <150 cells/µL and FeNO <25 ppb). At least one GINA criterion for T2 airway inflammation was documented in 70% of patients. T2 comorbidities were observed in 64% of patients. Conclusions: This analysis suggests that patients eligible for dupilumab treatment display various clinical and biochemical characteristics rather than one clear-cut phenotype.

Comprehensive Characterization of Difficult-to-Treat Asthma Reveals Near Absence of T2-Low Status.

Asthma is conventionally stratified as type 2 inflammation (T2)-high or T2-low disease. Identifying T2 status has therapeutic implications for patient management, but a real-world understanding of this T2 paradigm in difficult-to-treat and severe asthma remains limited. To identify the prevalence of T2-high status in difficult-to-treat asthma patients using a multicomponent definition and compare clinical and pathophysiologic characteristics between patients classified as T2-high and T2-low. We evaluated 388 biologic-naive patients from the Wessex Asthma Cohort of difficult asthma (WATCH) study in the United Kingdom. Type 2-high asthma was defined as 20 parts per billion or greater FeNO , 150 cells/μL or greater peripheral blood eosinophils, the need for maintenance oral corticosteroids, and/or clinically allergy-driven asthma. This multicomponent assessment identified T2-high asthma in 93% of patients (360 of 388). Body mass index, inhaled corticosteroid dose, asthma exacerbations, and common comorbidities did not differ by T2 status. Significantly worse airflow limitation was found in T2-high compared with T2-low patients (FEV1/FVC 65.9% vs 74.6%). Moreover, 75% of patients defined as having T2-low asthma had raised peripheral blood eosinophils within the preceding 10 years, which left only seven patients (1.8%) who had never had T2 signals. Incorporation of sputum eosinophilia 2% or greater into the multicomponent definition in a subset of 117 patients with induced sputum data similarly found that 96% (112 of 117) met criteria for T2-high asthma, 50% of whom (56 of 112) had sputum eosinophils 2% or greater. Almost all patients with difficult-to-treat asthma have T2-high disease; less than 2% of patients never display T2-defining criteria. This highlights a need to assess T2 status comprehensively in clinical practice before labeling a patient with difficult-to-treat asthma as T2-low.

Biomarkers for predicting type 2-high and uncontrolled asthma in real-world practice

BackgroundBlood eosinophil count (BEC), immunoglobulin (Ig) E, and fractional exhaled nitric oxide (FeNO) are key clinical indicators for identifying type 2 (T2) asthma. ObjectiveTo provide optimal cutoff points of T2 markers for assessing T2-high or uncontrolled asthma in real-world practice. MethodsVarious clinical and laboratory parameters were analyzed according to the result of T2 markers (BEC, serum-free IgE, and FeNO) in adults with asthma who had maintained antiasthmatic medications. The cutoff levels for representing uncontrolled asthma were determined using receiver operating characteristic analysis. Blood levels of periostin and eosinophil-derived neurotoxin were measured by enzyme-linked immunosorbent assay. Activation markers of circulating eosinophils (Siglec8+) and neutrophils (CD66+) were analyzed by flow cytometry. ResultsOf 133 patients with asthma, 23 (17.3%) had 3 T2 markers (BEC ≥ 300 cells/μL, serum-free IgE ≥ 120 ng/mL, and FeNO ≥ 25 parts per billion) and significantly higher levels of sputum eosinophils, blood eosinophil-derived neurotoxin, and Siglec8+ eosinophils but lower 1-second forced expiratory volume percentage, in addition to a higher rate of uncontrolled status (P < .05 for all). Furthermore, patients with uncontrolled asthma had significantly higher levels of FeNO and BEC with lower 1-second forced expiratory volume percentage (P < .05 for all). The optimal cutoff values for predicting uncontrolled asthma were found to be 22 parts per billion of FeNO levels, 161.4 cells/L of BECs, and 85.9 ng/mL of serum-free IgE levels. ConclusionWe suggest the optimal cutoff values of BEC, IgE, and FeNO for classifying T2-high or uncontrolled asthma, which could be applied as candidate biomarkers for targeting patients with asthma who require T2 biologics.

Lung epithelial cells: upstream targets in type 2-high asthma.

Over the last years, technological advances in the field of asthma have led to the identification of two disease endotypes, namely type 2-high and type 2-low asthma, characterized by different pathophysiologic mechanisms at a cellular and molecular level. Although specific immune cells are important contributors to each of the recognized asthma endotype, the lung epithelium is now regarded as a crucial player able to orchestrate responses to inhaled environmental triggers such as allergens and microbes. The impact of the epithelium goes beyond its physical barrier. It is nowadays considered as a part of the innate immune system that can actively respond to insults. Activated epithelial cells, by producing a specific set of cytokines, trigger innate and adaptive immune cells to cause pathology. Here, we review how the epithelium contributes to the development of Th2 sensitization to allergens and asthma with a "type 2-high" signature, in both murine models and human studies of this asthma endotype. We also discuss epithelial responses to respiratory viruses, like RV, RSV and SARS-CoV-2, and how these triggers influence not only asthma development but also asthma exacerbation. Finally, we also summarize the results of promising clinical trials using biologicals targeting epithelial-derived cytokines in asthmatic patients. This article is protected by copyright. All rights reserved.

Super-Responders to Biologic Treatment in Type 2–High Severe Asthma: Passing Fad or a Meaningful Phenotype?

Defining super-response to biologic treatment is a major concern in severe asthma. Although many definitions have been proposed, there is still a gap between the clinical perception of the super-response and a standardized classification. The current definition of super-response mainly relies on several clinical features, while many aspects of severe asthma inflammation and lung function are still poorly considered. Furthermore, many criteria of severe asthma super-response overlap with those of the clinical remission, leaving room for possible misclassifications. In this context, identifying the correct trajectory linking these 2 aspects of type 2-high severe asthma could help clinicians to understand which factors can predict a greater response to biologic therapies. In this paper, we review various aspects of super-response assessment, proposing some new criteria for its definition as well as new perspectives on its relationship with severe asthma clinical remission.

Is tezepelumab the ubiquitous biologic for severe asthma?

Biologic therapies have transformed severe asthma management.1 The use of these treatments has been based on the identification of specific phenotypic characteristics, which predict patient response to specific monoclonal antibody therapies. Measurements of total serum immunoglobulin (Ig)-E, blood eosinophil counts, and fractional concentration of exhaled nitric oxide (FeNO), enable the identification of specific type 2-high phenotypes responsive to specific biologic therapies. However, in clinical practice the paucity of biologics effective for both type 2-high and type 2-low asthma phenotypes is an important limitation of this therapeutic approach.

Severe asthma, more than that?

I was recently invited to write about the development of asthma management in the past decade. Biologic therapy came to my mind, and I was fascinated by the concept that asthma remission can potentially be achieved with this treatment (https://erj.ersjournals.com/content/early/2022/03/17/13993003.02583-2021). At the same time, I reflected on the management of one of my patients with severe asthma treated with biologics and the importance of looking for and managing comorbidities when treating patients with severe asthma. She was a young lady, and it was after more than a year of treatment with various agents for severe asthma, including high-dose inhaled corticosteroids, long-acting beta-agonist, anti-muscarinic agent, montelukast, azithromycin, systemic steroid and biologics (two biologics, started with one and then changed to the other with lack of effect) that we made the diagnosis of inducible laryngeal obstruction (ILO) (https://erj.ersjournals.com/content/50/3/1602221) that was causing the recurrent ‘asthma exacerbations’ and ICU admissions. Correct diagnosis is crucial for the treatment of asthma. However, having a confirmed diagnosis of asthma does not mean that it is the sole cause of respiratory symptoms/asthma exacerbations. This lady had features typical of asthma, including positive bronchodilator reversibility and her lung function varied with time with lower FEV1 at times of poor control or attacks. She also had Type-2 high asthma with high eosinophil blood count and exhaled nitric oxide levels. At the start of the illness, the patient improved with systemic steroid during hospitalisations. We did our usual workup for assessing comorbidities, such as looking for rhinitis and gastroesophageal reflux disease and excluded eosinophilic granulomatosis with polyangiitis. However, the young lady subsequently had more ‘asthma attacks’, and those episodes required ICU care, but no intubation was ever needed. Given the recurrent ICU admissions despite optimal pharmacotherapy for asthma, we have performed extensive investigations to exclude other diseases, including CT thorax, blood tests, echocardiogram and sleep study. During one of the ICU admissions, the patient was noted to have a low tidal and a high respiratory rate while on non-invasive pressure ventilation (NIV). Arterial blood gas taken during the ‘attacks’ showed respiratory acidosis with elevated pCO2 and normal alveolar-arterial gradient. The ‘attacks’ did not improve with asthma medications but responded to oxygen supplementation and NIV. We suspected ILO and were able to prove that by laryngoscopy. The patient had several ‘attacks’ of breathlessness afterwards, which were improved by benzodiazepines. We have thus stopped the unnecessary asthma medications for this patient, including biologics. The ILO was managed by speech therapist, psychologist, psychiatrist and ENT surgeon. Not every patient needs extensive investigations to search for comorbidities, but how far we need to go for patients with recurrent ‘asthma attacks’ would need clinical judgement and a personalized approach. Also, we have to think about ILO earlier in patients with severe asthma not responding well to therapy. We currently have potent medications, including biologics, for treating severe asthma, but we must ensure that these are given to the right patient. None declared.

Phenotype characterization and biomarker evaluation in moderate to severe type 2-high asthma.

There are two major pathological phenotypes of asthma, type 2 (T2)-high and T2-low asthma, which are important in determining treatment strategies. However, the characteristics and phenotypes of T2-high asthma have not yet been fully identified. This study aimed to identify the clinical characteristics and phenotypes of patients with T2-high asthma. This study used data from a nationwide asthma cohort study in Japan, NHOM Asthma Study. T2-high asthma was defined as a blood eosinophils count ≥ 300 /μL and/or fractional exhaled nitric oxide level ≥ 25 ppb, and the clinical characteristics and biomarkers were compared between T2-high and T2-low asthma. Furthermore, T2-high asthma was phenotyped via hierarchical cluster analysis using Ward's method. Patients with T2-high asthma were older, less likely to be female, had longer asthma duration, had lower pulmonary function, and had more comorbidities, including sinusitis and SAS. Patients with T2-high asthma showed higher serum thymus and activation-regulated chemokine and urinary leukotriene E4 levels and lower serum ST2 levels than those with T2-low asthma. There were four phenotypes among patients with T2-high asthma: Cluster 1 (youngest, early-onset, and atopic), Cluster 2 (long duration, eosinophilic, and low lung function), Cluster 3 (elderly, female-dominant, and late-onset), and Cluster 4 (elderly, late-onset, and asthma-COPD overlap-dominant). Patients with T2-high asthma have distinct characteristics and four distinct phenotypes, in which eosinophil-dominant Cluster 2 is the most severe phenotype. The present findings may be useful in precision medicine for asthma treatment in the future.

Comparative efficacy of tezepelumab to mepolizumab, benralizumab, and dupilumab in eosinophilic asthma: A Bayesian network meta-analysis

It is unclear how the efficacy of tezepelumab, approved for the treatment of type 2 high and low asthma, compares to the efficacy of other biologics for type 2-high asthma. We sought to conduct an indirect comparison of tezepelumab to dupilumab, benralizumab, and mepolizumab in the treatment of eosinophilic asthma. The investigators conducted a systematic review and Bayesian network meta-analyses. They identified randomized controlled trials indexed in PubMed, Embase, or Cochrane Central Register of Controlled Trials (CENTRAL) between January 1, 2000, and August 12, 2022. Outcomes included exacerbation rates, prebronchodilator FEV1, and the Asthma Control Questionnaire. Ten randomized controlled trials (n= 9201) met eligibility. Tezepelumab (relative risk: 0.63; 95% credible interval [CI]: 0.46-0.86) was associated with significantly lower exacerbation rates than benralizumab and larger improvements in FEV1 compared to mepolizumab (mean difference [MD]: 66; 95% CI: -33 to 170) and benralizumab (MD: 62; 95% CI: -22 to 150), though the 95% CI crossed the null value of 0. Mepolizumab improved the Asthma Control Questionnaire score the most, but this improvement was not significantly different from that of tezepelumab (tezepelumab vs mepolizumab; MD: 0.14; 95% CI: -0.10 to 0.38). For efficacy by clinically important thresholds, tezepelumab, mepolizumab, and dupilumab achieved a >99% probability of reducing exacerbation rates by ≥50% compared to placebo, but benralizumab had only a 66% probability of doing so. Tezepelumab and dupilumab had a probability of 1.00 of improving prebronchodilator FEV1 by ≥100 mL above placebo. Compared to mepolizumab, dupilumab had >90% chance for improving FEV1 by ≥50 mL, but none of the differences between biologics exceeded 100 mL. In individuals with eosinophilic asthma, tezepelumab and dupilumab were associated with greater improvements (although below clinical thresholds) in exacerbation rates and lung function than benralizumab or mepolizumab.

Dual activation of estrogen receptor alpha and glucocorticoid receptor upregulate CRTh2-mediated type 2 inflammation; mechanism driving asthma severity in women?

Type 2-high asthma is characterized by elevated levels of circulating Th2 cells and eosinophils, cells that express chemoattractant-homologous receptor expressed on Th2 cells (CRTh2). Severe asthma is more common in women than men; however, the underlying mechanism(s) remain elusive. Here we examined whether the relationship between severe asthma and type 2 inflammation differs by sex and if estrogen influences Th2 cell response to glucocorticoid (GC). Type 2 inflammation and the proportion of blood Th2 cells (CD4+ CRTh2+ ) were assessed in whole blood from subjects with asthma (n=66). The effects of GC and estrogen receptor alpha (ERα) agonist on in vitro differentiated Th2 cells were examined. Expression of CRTh2, type 2 cytokines and degree of apoptosis (Annexin V+ , 7-AAD) were determined by flow cytometry, qRT-PCR, western blot and ELISA. In severe asthma, the proportion of circulating Th2 cells and hospitalizations were higher in women than men. Women with severe asthma also had more Th2 cells and serum IL-13 than women with mild/moderate asthma. Th2 cells, eosinophils and CRTh2 mRNA correlated with clinical characteristics associated with asthma control in women but not men. In vitro, GC and ERα agonist treated Th2 cells exhibited less apoptosis, more CRTh2 as well as IL-5 and IL-13 following CRTh2 activation than Th2 cells treated with GC alone. Women with severe asthma had higher levels of circulating Th2 cells than men, which may be due to estrogen modifying the effects of GC, enhancing Th2 cell survival and type 2 cytokine production.

The membrane-associated ubiquitin ligases MARCH2 and MARCH3 target IL-5 receptor alpha to negatively regulate eosinophilic airway inflammation.

Interleukin 5 (IL-5) plays crucial roles in type 2-high asthma by mediating eosinophil maturation, activation, chemotaxis and survival. Inhibition of IL-5 signaling is considered a strategy for asthma treatment. Here, we identified MARCH2 and MARCH3 as critical negative regulators of IL-5-triggered signaling. MARCH2 and MARCH3 associate with the IL-5 receptor α chain (IL-5Rα) and mediate its K27-linked polyubiquitination at K379 and K383, respectively, and its subsequent lysosomal degradation. Deficiency of MARCH2 or MARCH3 modestly increases the level of IL-5Rα and enhances IL-5-induced signaling, whereas double knockout of MARCH2/3 has a more dramatic effect. March2/3 double knockout markedly increases the proportions of eosinophils in the bone marrow and peripheral blood in mice. Double knockout of March2/3 aggravates ovalbumin (OVA)-induced eosinophilia and causes increased inflammatory cell infiltration, peribronchial mucus secretion and production of Th2 cytokines. Neutralization of Il-5 attenuates OVA-induced airway inflammation and the enhanced effects of March2/3 double deficiency. These findings suggest that MARCH2 and MARCH3 play redundant roles in targeting IL-5Rα for degradation and negatively regulating allergic airway inflammation.

Suppression of airway allergic eosinophilia by Hp-TGM, a helminth mimic of TGF-β.

Type 2-high asthma is a chronic inflammatory disease of the airways which is increasingly prevalent in countries where helminth parasite infections are rare, and characterized by T helper 2 (Th2)-dependent accumulation of eosinophils in the lungs. Regulatory cytokines such as TGF-β can restrain inflammatory reactions, dampen allergic Th2 responses, and control eosinophil activation. The murine helminth parasite Heligmosomoides polygyrus releases a TGF-β mimic (Hp-TGM) that replicates the biological and functional properties of TGF-β despite bearing no structural similarity to the mammalian protein. Here, we investigated if Hp-TGM could alleviate allergic airway inflammation in mice exposed to Alternaria alternata allergen, house dust mite (HDM) extract or alum-adjuvanted ovalbumin protein (OVA). Intranasal administration of Hp-TGM during Alternaria exposure sharply reduced airway and lung tissue eosinophilia along with bronchoalveolar lavage fluid IL-5 and lung IL-33 cytokine levels at 24 h. The protective effect of Hp-TGM on airway eosinophilia was also obtained in the longer T-cell mediated models of HDM or OVA sensitisation with significant inhibition of eotaxin-1, IL-4 and IL-13 responses depending on the model and time-point. Hp-TGM was also protective when administered parenterally either when given at the time of allergic sensitisation or during airway allergen challenge. This project has taken the first steps in identifying the role of Hp-TGM in allergic asthma and highlighted its ability to control lung inflammation and allergic pathology. Future research will investigate the mode of action of Hp-TGM against airway allergic eosinophilia, and further explore its potential to be developed as a biotherapeutic in allergic asthma.

Chronic Allergen Challenge Induces Corticosteroid Insensitivity With Persistent Airway Remodeling and Type 2 Inflammation.

Type 2-high severe asthma is described as a distinct endotype with Th2 inflammation, high eosinophil lung infiltration, impaired lung function, and reduced corticosteroid sensitivity. While the inflammatory milieu is similar to mild asthma, patients with type 2-high severe asthma likely have underlying mechanisms that sustain asthma pathophysiology despite corticosteroid treatments. Acute and chronic allergen models induce robust type 2 inflammatory responses, however differences in corticosteroid sensitivity remains poorly understood. In the present study, we sensitized and challenged mice with ovalbumin (OVA; acute model) or mixed allergens (MA; chronic model). Corticosteroid sensitivity was assessed by administering vehicle, 1, or 3 mg/kg fluticasone propionate (FP) and examining key asthmatic features such as airway inflammation, remodeling, hyperresponsiveness, and antioxidant capacity. Both acute and chronic allergen exposure exhibited enhanced AHR, immune cell infiltration, airway inflammation, and remodeling, but corticosteroids were unable to fully alleviate inflammation, AHR, and airway smooth muscle mass in MA-challenged mice. While there were no differences in antioxidant capacity, persistent IL-4+ Th2 cell population suggests the MA model induces type 2 inflammation that is insensitive to corticosteroids. Our data indicate that chronic allergen exposure is associated with more persistent type 2 immune responses and corticosteroid insensitivity. Understanding differences between acute and chronic allergen models could unlock underlying mechanisms related to type 2-high severe asthma.