Eosinophilic Asthma Research Articles

Asthma and COVID-19: Unveiling Outcome Disparities and Treatment Impact Based on Distinct Endotypes.

Epidemiologic studies on asthmatics and in vitro data suggest a protective role of T2 inflammation in SARS-CoV-2 infection. Using a large, multisite cohort, we studied clinical outcomes following SARS-CoV-2 infection in multiple asthma endotypes and examined the effects of T2-directed biologics in infected asthmatics.in Methods: The National COVID Cohort Collaborative (N3C) Data Enclave was used to identify and stratify asthmatic patients by endotype to include non-T2 and T2 asthmatics, as well as exposure to T2-directed biologic therapy. We evaluated the risk of hospitalization, invasive mechanical ventilation, and 90-day mortality by endotype and exposure to biologics. For this study, 402,376 patients met inclusion criteria, of which 138,142 (34%) were characterized as non-T2 and 264,234 (66%) as T2 asthmatics, a group further divided into 104,823 (26%) atopic, 84,440 (21%) eosinophilic, and 74,971 (19%) T2-high asthmatic endotypes. Compared to non-T2 asthmatics, atopic and T2-high asthmatics experienced decreased odds of hospitalization, and 90-day mortality. Conversely, eosinophilic asthmatics experienced higher odds of hospitalization, intubation, and 90-day mortality. Exposure to T2-directed biologic therapies did not alter outcomes after propensity score matching. In contrast, maximum eosinophil count and recent systemic corticosteroid use were directly correlated with increased odds of all outcomes. COVID-19 outcomes differ depending on asthma endotype, with atopic asthmatics experiencing lower odds and eosinophilic asthmatics experiencing higher odds of deleterious outcomes. T2-directed biologic treatment did not alter these outcomes but recent systemic corticosteroid use predisposes all asthmatics patients to adverse outcomes. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Subtype prevalence and treatment implication in adolescents and adults with mild-to-moderate asthma: A systematic review and meta-analysis

BackgroundInhaled corticosteroid (ICS) containing regimens are the mainstay for treating asthma despite usually being ineffective in non-eosinophilic asthma (NEA). Data on the prevalence of NEA versus eosinophilic asthma (EA) in mild-to-moderate asthmatics is limited. ObjectiveTo systematically review the subtype prevalence of mild-to-moderate asthma in adolescents and adults using sputum inflammatory cell analysis and their responses to ICS. MethodsWe searched electronic databases (PubMed, Scopus, EMBASE, Cochrane) for studies in adolescents and adults with mild-to-moderate asthma. The primary outcome was the prevalence of asthma subtypes based on sputum inflammatory cell analysis, categorized into EA and NEA. The secondary outcome involved comparing asthma outcomes between different subtypes following ICS therapy. Certainty of evidence was reported for each pooled analysis. ResultsEighteen studies involving 3,533 adolescents and adults with mild-to-moderate asthmatics were reviewed. The pooled prevalence (95% confidence interval, CI) of NEA was estimated at 40.39% (27.54, 53.93) in patients with ICS naïve with very low certainty of evidence. Upon reevaluating sputum cytology, approximately 20% to 30% of patients initially classified as having NEA transitioned to the EA subtype. EA patients showed significant improvements in asthma symptoms, FEV1 [standardized mean difference (95% CI): 0.79 (0.30, 1.27)], and airway hyperresponsiveness [1.34 (0.29, 2.40)] following ICS therapy, while NEA patients exhibited limited response. ConclusionA high proportion of adolescents and adults with mild-to-moderate asthma were identified as having the NEA subtype, which exhibited a poor response to ICS. A thorough diagnostic evaluation before initiating treatment should be integrated into clinical practice.

Early treatment response to mepolizumab predicts clinical remission in severe eosinophilic asthma

Mepolizumab can induce an early response and clinical remission in people with severe eosinophilic asthma (SEA). We questioned whether early response to mepolizumab could predict future asthma remission, and sought to identify the best predictor of treatment response to mepolizumab for achieving remission. The Australian Mepolizumab Registry was used to investigate the early response to mepolizumab at 3 and 6 months and relate this to clinical remission at 12 months. Treatment response was assessed using the Asthma Control Questionnaire (ACQ)-5, oral corticosteroid (OCS) dose, exacerbation frequency, and post-bronchodilator FEV1. Clinical remission, assessed at 12 months, was defined as ACQ-5 ≤1.0 at 12 months, no exacerbations in the previous 6 months, and no OCS use for asthma in the previous 6 months. We estimated the optimism-corrected area under the curve (AUC) for internal validation. We analyzed 255 participants with SEA. Seventy-eight (30.6%) participants achieved clinical remission at 12 months. A prediction model including ACQ-5 score, exacerbation frequency, OCS dose, and post-bronchodilator FEV1 at 6 months was more predictive of achieving remission than measures at 3 months. ACQ-5 score at 6 months had the highest optimism-corrected AUC of 0.778 [95% CI: 0.719-0.833]. ACQ-5 score <1.5 at 6 months had a sensitivity of 85.9% for achieving clinical remission, while ACQ-5 score <0.75 had a specificity of 84.7%. ACQ-5 score at 6 months was the best predictor of achieving clinical remission at 12 months in people with SEA treated with mepolizumab. These results can be used to design a treat-to-target paradigm for asthma, where treatment response is assessed at 6 months to predict clinical remission.

Case Report: Dual monoclonal antibody therapy in chronic rhinosinusitis with nasal polyps and severe eosinophilic asthma—a proteome analysis

Case Report: Dual monoclonal antibody therapy in chronic rhinosinusitis with nasal polyps and severe eosinophilic asthma—a proteome analysis

Skin Surface Lipid-RNA Profile Obtained from Patients with Severe Asthma After Benralizumab Treatment.

Examining human coding and non-coding RNAs present in skin surface lipids (SSL-RNAs) offers a promising approach to understanding the physiological state of the skin. Benralizumab treatment can reduce exacerbations and improve symptom control and quality of life in patients with severe eosinophilic asthma. Although this treatment effectively depletes peripheral blood eosinophils, the impact of benralizumab on SSL-RNA remains completely unknown. To investigate the effects of benralizumab treatment on SSL-RNA profiles in patients with severe asthma. Skin samples were non-invasively collected from patients before and after one year of benralizumab treatment. Sixteen patients were enrolled, but the SSL-RNA analysis was only feasible for five patients due to collection challenges, mainly in female participants. Following benralizumab treatment, asthma symptoms, exacerbation rates, and lung function parameters improved. Peripheral blood eosinophils were completely depleted and serum eotaxin-1 levels increased. SSL-RNA analysis revealed differential expression of 134 genes, with significant downregulation of immune-related pathways and genes associated with neutrophilic inflammation. These findings suggest a suppression of both type 2 and non-type 2 inflammation in response to benralizumab treatment, with potential implications for asthma management. However, the limitations of the study include a small sample size and challenges in sebum collection, particularly among female participants. Although the noninvasive nature of this sampling method makes it attractive for both research and clinical applications, additional studies are needed to fully investigate the potential of SSL-RNA analysis as a noninvasive biomarker to assess treatment response in asthma.

Benralizumab: Effectiveness in Patients with Uncontrolled Severe Eosinophilic Asthma at 6 and 12 Months at a Third-Level Care Hospital. Capacity for ICS-LABA Therapy Reduction.

Asthma is a health condition with worldwide relevance, evaluated based on the necessary treatment to control symptoms and exacerbations. Severe asthma is uncontrolled despite high doses of ICS-LABA and treatment for triggering factors. Severe eosinophilic asthma is characterized by an increase in eosinophils in the peripheral circulation, walls, and passages of the respiratory tract. Biologic treatments such as benralizumab have demonstrated effectiveness as aids in decreasing respiratory tract inflammation and improving the management of symptoms in patients living with asthma. To assess the efficacy and safety of benralizumab as an add-on therapy for patients with severe, uncontrolled asthma and elevated blood eosinophil counts. Observational, analytic and ambispective study in 21 patients diagnosed with severe eosinophilic asthma treated with benralizumab, to determine the treatment's effectiveness through the change in estimated respiratory function by spirometry through the forced expiratory volume in one second (FEV1) value, reduction in second controlling treatment, serum eosinophil reduction, change in the Asthma Control Test score and the Asthma Control Questionnaire test at 6 and 16 months of treatment. An average difference of 241.43 mL (±461.43) in FEV1 at 6 months was found, as well as an average FeNO reduction of 49.8 ppm and eosinophil reduction of 612.78 cells at 12 months of treatment, additionally, CSI requirements were reduced in 95% of patients. Benralizumab improved respiratory function as well as key biomarkers such as eosinophil count, exhaled nitric oxide fraction (FeNO), which reflected in a decreased requirement of inhaled corticosteroids and improved symptom control.

Targeting of the IL-5 pathway in severe asthma reduces mast cell progenitors

BackgroundTherapies targeting interleukin-5 (IL-5) or its receptor (IL-5Rα) are currently used to treat patients with severe eosinophilic asthma. ObjectiveTo investigate the impact of anti-IL-5 and anti-IL-5Rα biological therapies on mast cells (MCs) and their progenitors. MethodsSurface IL-5Rα expression was investigated on MCs and their progenitors in mouse lungs and bone marrow, and in human lungs and blood. Isolated human MC progenitors cultured in the presence or absence of IL-5 were analyzed in vitro. Circulating MC progenitors were quantified in patients with severe asthma, before and after anti-IL-5 (mepolizumab) or anti-IL-5Rα (benralizumab) therapy. Gene expression analysis of MC progenitors was performed before and after anti-IL-5Rα therapy. ResultsApproximately 50% of the human primary lung MCs, and 30% of the human MC progenitors from individuals with allergic asthma expressed IL-5Rα. In patients with mild-to-moderate allergic asthma and mice with acute allergic airway inflammation, the fraction of IL-5Rα + MC progenitors was elevated. Additionally, IL-5 promoted the proliferation and/or survival of isolated human MC progenitors. Further, patients with severe asthma from two independent cohorts demonstrated a reduction of blood MC progenitors after anti-IL-5 or anti-IL-5Rα treatment. This was associated with improved asthma control, as well as a decline in both blood eosinophils and Th2 cells. Finally, the blood MC progenitors remaining after anti-IL-5Rα (benralizumab) treatment exhibited a downregulated expression of genes involved in growth and proliferation. ConclusionThis study introduces the possibility that the clinical effects of targeting IL-5/IL-5Rα in severe asthma also may involve reduction of MC populations.

Updated insights into adverse events associated with mepolizumab: a disproportionality analysis from the FDA adverse event reporting system database

BackgroundMepolizumab, a monoclonal antibody targeting interleukin-5, is used to treat severe eosinophilic asthma and other eosinophilia-related conditions. Given its growing use, there is a pressing need for the latest data to improve the understanding and management of its adverse events (AEs). This study aimed to investigate the safety of mepolizumab by analyzing the pharmacovigilance database of the US Food and Drug Administration.MethodsThe AE signals associated with mepolizumab from 2015 to 2024 were analyzed and the correlations using reporting ratios (RORs) quantified. Subgroup analyses were conducted to understand AEs in individuals ≤ 18 years of age. We also used time-to-onset (TTO) analysis to examine AE occurrence patterns.ResultsIn total, 82,478 AE reports linked to mepolizumab therapy were included. Our analysis, involving 24,156 patients, revealed a predominance of female patients, with the highest incidence of AEs occurring in those aged 18–65 years. Disproportionality analyses revealed significant signals across various system organ classifications (SOCs), most prominently respiratory, thoracic, and mediastinal disorders (ROR = 5.12, 95% confidence intervals [CI] 5.03–5.21), infections and infestations (ROR = 1.86, 95% CI 1.81–1.90), and immune system disorders (ROR = 1.14, 95% CI 1.08–1.21). The highest ROR was found for asthma crisis (ROR = 104.90, 95% CI 95.31–115.44) at the preferred term (PT) level, and the other notables were coronavirus infection (ROR = 7.33, 95% CI 6.05–8.88) and coronavirus disease 2019 (COVID-19) (ROR = 1.34, 95% CI 1.23–1.47). A subgroup analysis of patients ≤ 18 years old identified four significant SOC signals, with the highest ROR in respiratory, thoracic, and mediastinal disorders (ROR = 5.28, 95% CI 4.17–6.68). PT analysis revealed significant AEs, such as wheezing, bronchospasm, and chest discomfort. TTO analysis revealed that 18.5% of AEs occurred within the first 30 days of treatment. The Weibull shape parameter indicated an “early failure-type” pattern for mepolizumab-associated AEs, underscoring the need for vigilant monitoring during the initial stages of therapy.ConclusionOur study highlights the importance of post-market surveillance for monitoring the safety of mepolizumab, which revealed significant AE signals, particularly for respiratory diseases, infections, and immune system complications. The association with opportunistic infections, including COVID-19, highlights the need for vigilant surveillance and further research.

Eosinophil count testing in patients with asthma varies by healthcare provider type in the US: a retrospective study

BackgroundPatients with asthma with an eosinophilic phenotype may be eligible for additional treatment options to improve disease control; however, the prevalence and frequency of eosinophil testing is unknown. This study assessed blood eosinophil count testing prevalence in patients with asthma by exacerbation frequency and healthcare provider (HCP) type.MethodsThis was a retrospective, longitudinal, real-world study (GSK ID: 214470) utilizing the Merative Explorys® Universe electronic health records database. Eligible patients had ≥ 2 asthma diagnostic codes (January 2016–December 2018) (Index date: first asthma diagnosis). Outcomes included patient demographics and clinical characteristics (12 months pre-index [baseline]), and prevalence of blood eosinophil count testing, stratified by exacerbation frequency (infrequent exacerbations [< 2]) or frequent exacerbations [≥ 2] or primary HCP (Allergist/Pulmonologist, a primary care physician [PCP] or other HCP) during the 12 months post-index (follow-up).ResultsOf 400,254 patients included (mean age: 51.2 years; 70.8% female), the most common provider type at baseline was a PCP (76.8%). A higher proportion of patients with frequent exacerbations had blood eosinophil count tests at baseline (55.4–69.5%) and follow-up (67.9–75.1%), compared with patients with infrequent exacerbations (55.5–63.7%, 62.4–67.3%). Significantly more patients in the Allergist/Pulmonologist subgroup had ≥ 1 blood eosinophil count test result compared with patients in the PCP subgroup at both baseline (59.9% vs. 50.7%; p < 0.001) and follow-up (59.0% vs. 56.2%; p < 0.001). In the total population, the mean (SD) number of tests ordered was 3.4 (5.3) and 4.1 (6.4) during the baseline and follow-up periods, respectively. A greater mean number of tests were ordered for patients with frequent exacerbations, most apparently in the Allergist/Pulmonologist subgroup during baseline and follow-up (7.4 vs. 4.9). For patients with frequent exacerbations and blood eosinophil count test results, the mean (SD) number of tests ranged from 3.1 (4.6) to 5.8 (8.3) at baseline and 5.1 (8.5) to 7.4 (10.6) during follow-up.ConclusionsThe prevalence of blood eosinophil count testing in patients with asthma remains suboptimal. Routine blood eosinophil count testing should be considered by HCPs for patients with asthma to increase identification of the eosinophilic asthma phenotype, which may inform the decision to advance to targeted biologic therapy.

Transforming Care in SEA: Evidence and Considerations for Evolution of the Current Treatment Paradigm

This article reviews an industry symposium held on 8 September 2024 as part of the European Respiratory Society (ERS) Congress 2024 in Vienna, Austria, which brought together four experts to discuss the current treatment paradigm for severe eosinophilic asthma (SEA), including the role of biologics and background medication tapering. Katrin Milger-Kneidinger, Professor of Respiratory Medicine at the University Hospital of the Ludwig Maximilian University Munich (LMU), in Germany, and the MedUni Graz, in Austria, explored the critical role eosinophils play in SEA pathology and how biologic therapies targeting eosinophils can address key disease features, including airway remodelling, airway hyperresponsiveness (AHR), and mucus production. Felix Herth, Professor of Pulmonary and Critical Care Medicine at Thoraxklinik Heidelberg, Heidelberg University Hospital, in Germany, discussed persistent airflow obstruction (PAO) in patients with SEA, focusing on a typical patient profile to understand the clinical manifestation and opportunities for management. Stephanie Korn, Professor of Pulmonary and Respiratory Medicine at Thoraxklinik Heidelberg, Heidelberg University Hospital, in Germany, and Head of the Clinical Research Centre, Institute für Klinische Forschung (IKP) Pneumologie in Mainz, Germany, presented on remission as a clinical target in SEA, focusing on how biologics can help achieve remission in some patients. Lastly, in a discussion led by symposium chair Stefano Del Giacco, Professor of Medicine, Allergy, and Clinical Immunology, at the University of Cagliari, Sardinia, in Italy, the experts agreed that a positive practice change would be to get more patients with relevant clinical manifestations on biologics, and that background medication tapering, when appropriate, could lead to improved patient outcomes and quality of life (QoL) in SEA.

Achieving clinical remission in asthma with mepolizumab: a subanalysis on vitamin D as a predictor of response

Objective Mepolizumab, an anti-IL-5 monoclonal antibody, has shown promise in reducing exacerbations and steroid dependency in severe eosinophilic asthma. This study aims to evaluate the effectiveness of mepolizumab in achieving clinical remission in asthma over 12 months and explore Vitamin D levels as a predictor of response. Method We assessed Asthma Control Questionnaire (ACQ) scores, spirometry, number of exacerbations, oral corticosteroid (OCS) use, and inhaled corticosteroid (ICS) use in 32 patients, observing significant clinical improvements. Data were collected 1 year prior to starting mepolizumab and one year after starting mepolizumab. Nasal polyps were not seen in all the patients, and computed tomography of para-nasal sinuses are not available for all the patients, so nasal polyps status are not evaluated to avoid any bias. Result Our results indicate that 12 patients achieved clinical remission after starting mepolizumab, with a strong correlation between higher Vitamin D levels and positive treatment outcomes. This suggests that optimizing Vitamin D levels could enhance the response to mepolizumab in asthma patients, and help in achieving better asthma control. Conclusion Mepolizumab is an effective treatment for severe eosinophilic asthma, significantly improving clinical outcomes and reducing corticosteroid use. This study highlights the importance of Vitamin D as a predictor of response to mepolizumab, suggesting that higher Vitamin D levels may enhance treatment efficacy.

Impact of biological therapies on clinical outcomes in patients with severe eosinophilic asthma with chronic rhinosinusitis: an observational study from Saudi Arabia

BackgroundWe aimed to study the impact of biological therapies in Saudi Arabia on patients with severe asthma (SA) combined with chronic rhinosinusitis (CRS) in terms of clinical outcomes.MethodsThis is a retrospective observational cohort research that was undertaken at the severe asthma clinics of the Armed Forces Hospital of the Southern Region (AFHSR) and King Khalid University Hospital, Abha, from March to September 2022 to delineate the effects of 3 biological therapies (dupilumab, benralizumab, and omalizumab) in adults with SA and concomitant CRS. Clinical outcomes assessed included asthma exacerbation frequency, hospitalization rates, use of oral corticosteroids (OCs), and the asthma control test (ACT) scores before and 1 year after biological therapies.ResultsEighty patients were enrolled, with a mean age of 46.68. There were 45 (56%) females and 35 (44%) males. There was a notifiable decrease in the frequency of exacerbations and hospitalization and in the number of patients who received OCs after 6 and 12 months of biological therapies compared to pre-biological therapies, respectively (p < 0.001 each), while there was a significant increase in the ACT scores at 6 and 12 months post-biological therapies, compared to pre-biological therapies, respectively (p < 0.001). These significant differences were maintained with all the 3 biologics used.ConclusionsResults from the first study from two large Saudi Arabian tertiary centers for patients with SA and CRS agree with and support those of worldwide real-life ones. One-year follow-up showed the effectiveness of the 3 drugs in terms of reduced frequency of asthma hospitalizations and exacerbations, the use of OCs, and improved ACT scores. Further prospective multicenter studies are warranted.

Targeting the IL-5 pathway in eosinophilic asthma: A comparison of anti-IL-5 versus anti-IL-5 receptor agents.

Eosinophilic asthma is characterized by frequent exacerbations, poor symptom control and accelerated lung function decline. It is now recognized that the immune response underlying eosinophilic asthma involves a complex network of interconnected pathways from both the adaptive and innate immune systems. Within this response, interleukin-5 (IL-5) plays a central role in eosinophil differentiation, activation and survival and has emerged as a key target for therapies treating severe asthma. The monoclonal antibodies mepolizumab and reslizumab target the ligand IL-5, preventing its interaction with eosinophils; in contrast, benralizumab binds to the IL-5 receptor (IL-5R), preventing IL-5 from binding and leading to substantially greater eosinophil reduction by enhanced antibody-dependent cell-mediated cytotoxicity. Although no direct head-to-head clinical trials of asthma have been published to formally evaluate the clinical significance of these different therapeutic approaches, the potential benefits of partial versus complete eosinophil depletion continue to remain an important area of study and debate. Here, we review the existing real-world and clinical study data of anti-IL-5/anti-IL-5R therapies in severe eosinophilic asthma.

Cluster Analysis Identifies Patients With Severe Eosinophilic Asthma Who Achieve Super-Response and Remission With Mepolizumab.

This study identifies two distinct subgroups of patients with severe eosinophilic asthma who respond differently to mepolizumab. Cluster analysis reveals that patients with a family history of asthma, positive skin prick tests and higher baseline lung function have better treatment outcomes, highlighting the value of personalised treatment strategies.

Distinct trajectories of treatment response to mepolizumab toward remission in patients with severe eosinophilic asthma.

Patients with severe eosinophilic asthma, characterised by a high disease burden, benefit from mepolizumab, which improves symptoms and reduces exacerbations, potentially leading to clinical remission in a subgroup. This study aimed to identify treatment response trajectories to mepolizumab for severe eosinophilic asthma and to assess the achievement of clinical remission.Data from the Australian Mepolizumab Registry were used to assess treatment responses at 3, 6, and 12 months. The treatment response trajectories were identified using a group-based trajectory model. The proportions achieving clinical remission at 12 months, which was defined as well-controlled symptoms, no exacerbations, and no oral corticosteroid (OCS) use for asthma management, were compared between trajectories, and baseline predictors of the trajectories were identified using logistic regression analysis.We identified three trajectory groups: group 1, responsive asthma with less OCS use (n=170); group 2, responsive late-onset asthma (n=58); and group 3, obstructed and less responsive asthma (n=70). Groups 1 and 2 demonstrated higher proportions achieving clinical remission at 36.5% and 25.9%, respectively, compared to group 3 with 5.7% (p <0.001). Baseline predictors for assigned groups included lower OCS dose in group 1; greater FEV1% predicted, higher Asthma Quality of Life Questionnaire score, higher OCS dose, and nasal polyps in group 2; with group 3 as the reference.Treatment response to mepolizumab in severe eosinophilic asthma follows 3 trajectories with varying proportions achieving clinical remission and differing baseline characteristics. Treatment response variability may influence the achievement of clinical remission with mepolizumab therapy.

Blood transcriptomics reveal systemic eosinophilic and neutrophilic inflammation patterns in patients with nasal polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic sinonasal disease characterized by heterogeneous inflammation. However, the presence of systemic inflammation heterogeneity in CRSwNP patients remains unknown. This study aims to profile transcriptomic alterations in the blood of CRSwNP patients and characterize the CRSwNP heterogeneity based on blood transcriptomic biomarkers. Patients with CRSwNP were prospectively recruited from three hospitals and chronologically divided into exploratory (n=123) and independent validation (n=46) cohorts. Transcriptomic profiles were generated by whole blood mRNA sequencing and subjected to patient clustering, differential expression, and pathway analysis. Differences in immune pattern and clinicopathologic features between clusters were assessed. A transcriptomic signature was defined and applied to an independent cohort to validate the findings. CRSwNP patients showed diverse blood transcriptomic profiles versus healthy controls, or when stratified by tissue and blood eosinophils and asthma comorbidity. Transcriptome-wide correlation analysis revealed a transcriptional signature associated with blood eosinophil levels, consisting of nine T2-related genes (CLC, SIGLEC8, ALOX15, IL5RA, PTGDR2, CCL23, CCR3, EPX and IL1RL1). Three distinct clusters with differing systemic eosinophilic and neutrophilic inflammation patterns and asthma comorbidity were identified based on transcriptomic profiling of T2 and T1/3-related blood biomarkers. A 36-gene signature was developed by machine learning and accurately predicted the three CRSwNP subtypes. Validation on an independent cohort confirmed the prediction robustness. There is heterogeneous systemic inflammation associated with eosinophilic and neutrophilic patterns in patients with CRSwNP. Endotyping based on blood transcriptomic biomarkers might lead to more personalized treatment strategies for CRSwNP in the future.

Inflammation-induced loss of CFTR-expressing airway ionocytes in non-eosinophilic asthma.

Severe asthma is a heterogeneous disease with subtype classification according to dominant airway infiltrates, including eosinophilic (Type 2 high), or non-eosinophilic asthma. Non-eosinophilic asthma is further divided into paucigranulocytic or neutrophilic asthma characterized by elevated neutrophils, and mixed Type 1 and Type 17 cytokines in the airways. Severe non-eosinophilic asthma has few effective treatments and many patients do not qualify for biologic therapies. The cystic fibrosis transmembrane conductance regulator (CFTR) is dysregulated in multiple respiratory diseases including cystic fibrosis and chronic obstructive pulmonary disease and has proven a valuable therapeutic target. We hypothesized that the CFTR may also play a role in non-eosinophilic asthma. Patient-derived human bronchial epithelial cells (hBECs) were isolated and differentiated at the air-liquid interface. Single cell RNA-sequencing (scRNAseq) was used to identify epithelial cell subtypes and transcriptional activity. Ion transport was investigated with Ussing chambers and immunofluorescent quantification of ionocyte abundance in human airway epithelial cells and murine models of asthma. We identified that hBECs from patients with non-eosinophilic asthma had reduced CFTR function, and did not differentiate into CFTR-expressing ionocytes compared to those from eosinophilic asthma or healthy donors. Similarly, ionocytes were also diminished in the airways of a murine model of neutrophilic-dominant but not eosinophilic asthma. Treatment of hBECs from healthy donors with a neutrophilic asthma-like inflammatory cytokine mixture led to a reduction in ionocytes. Inflammation-induced loss of CFTR-expressing ionocytes in airway cells from non-eosinophilic asthma may represent a key feature of disease pathogenesis and a novel drug target.

Estrogen signaling suppresses tumor-associated tissue eosinophilia to promote breast tumor growth.

Estrogens regulate eosinophilia in asthma and other inflammatory diseases. Further, peripheral eosinophilia and tumor-associated tissue eosinophilia (TATE) predicts a better response to immune checkpoint blockade (ICB) in breast cancer. However, how and if estrogens affect eosinophil biology in tumors and how this influences ICB efficacy has not been determined. Here, we report that estrogens decrease the number of peripheral eosinophils and TATE, and this contributes to increased tumor growth in validated murine models of breast cancer and melanoma. Moreover, estrogen signaling in healthy female mice also suppressed peripheral eosinophil prevalence by decreasing the proliferation and survival of maturing eosinophils. Inhibiting estrogen receptor (ER) signaling decreased tumor growth in an eosinophil-dependent manner. Further, the efficacy of ICBs was increased when administered in combination with anti-estrogens. These findings highlight the importance of ER signaling as a regulator of eosinophil biology and TATE and highlight the potential near-term clinical application of ER modulators to increase ICB efficacy in multiple tumor types.

Exploring CD26-/lo subpopulations of lymphocytes in asthma phenotype and severity: A novel CD4+ T cell subset expressing archetypical granulocyte proteins.

Asthma pathology may induce changes in naïve/memory lymphocyte proportions assessable through the evaluation of surface CD26 (dipeptidyl peptidase 4/DPP4) levels. Our aim was to investigate the association of asthma phenotype/severity with the relative frequency of CD26-/lo, CD26int and CD26hi subsets within different lymphocyte populations. The proportion of CD26-/lo, CD26int and CD26hi subsets within CD4+ effector T cells (Teff), total CD4- lymphocytes, γδ-T cells, NK cells and NKT cells was measured in peripheral blood samples from healthy (N = 30) and asthma (N = 119) donors with different phenotypes/severities by flow cytometry. We performed K-means clustering analysis and further characterised the CD4+CD26-/lo Teff cell subset by LC-MS/MS and immunofluorescence. Cluster analysis including clinical and flow cytometry data resulted in four groups, two of them with opposite inflammatory profiles (neutrophilic vs. eosinophilic). Neutrophilic asthma presented reduced CD4-CD26hi cells, which negatively correlated with systemic inflammation. Eosinophilic asthma displayed a general expansion of CD26-/lo subsets. Specifically, CD4+CD26-/lo Teff expansion was confirmed in asthma, especially in atopic patients. Proteomic characterisation of this subset with a TEM/TEMRA phenotype revealed upregulated levels of innate (e.g. MPO and RNASE2) and cytoskeleton/extracellular matrix (e.g. MMP9 and ACTN1) proteins. Immunofluorescence assays confirmed the presence of atypical proteins for CD4+ T cells, and an enrichment in 'flower-like' nuclei and MMP9/RNASE2 levels in CD4+CD26-/lo Teff compared to CD4+ T lymphocytes. There is an association between CD26 levels in different lymphocyte subsets and asthma phenotype/severity. CD4+CD26-/loTEMRA cells expressing innate proteins specific to eosinophils/neutrophils could be determinant in sustaining long-term inflammation in adult allergic asthma.

Low CD46 expression on activated CD4+ T cells predict improved Th1 cell reactivity to calcitriol in majority of patients with allergic eosinophilic asthma and healthy donors.

Previous research showed that the intracellular complement system, with CD46 as its central molecule, regulates the Th1 response associated with IFN-γ production and transition to a type 1 regulatory response (Tr1) characterized by IL-10 production. This transition can be influenced by a vitamin D (calcitriol), favouring a shift towards Tr1 cells and increased IL-10 production, as described in some autoimmune diseases. It is unknown whether calcitriol modulates CD46-induced Th1 response towards regulatory type 1 T cells (Tr1) in allergic eosinophilic asthma and its value in relation to reducing inflammatory response. CD4+ T cells from 58 patients with allergic eosinophilic asthma (AEA) and 49 healthy donors (HDs) were stimulated with αCD3/αCD46/IL-2 or αCD3/αCD46/IL-2/Calcitriol in vitro for 60 h and analyzed by flow cytometry. IFN-γ and IL-10 levels in cell culture supernatants were measured using ELISA. CD4+ T cells from patients with AEA demonstrated elevated CD46 expression in both the non-activated state and under stimulation conditions with αCD3/αCD46/IL-2 or αCD3/αCD46/IL-2/Calcitriol. Moreover, CD46 expression in AEA patients fluctuated with the pollen season, showing a significant increase during period of low pollen exposure. Calcitriol further induced CD4+Tr1 cells from in vitro generated CD4+Th1 cells in both HDs and AEA patients. However, in both cohorts were individuals (HDs: 35/49, AEA: 40/58) who responded to calcitriol with a more pronounced regulatory response. The calcitriol-induced regulatory effect manifested by a stronger surface decrease of CD46 on activated CD4+ T cells (by 40% in HDs and by 26% in AEA), accompanied by a significant inhibition of IFN-γ and increased IL-10 production (by 31% in HDs and by 85% in AEA). These individuals were termed as the CD46D group. Contrary to this, calcitriol induced an increase in CD46 expression at the CD4+ T cell surface in a minor group of HDs (14/49), and AEA patients (18/58), who were termed as the CD46I group. In CD46I group, CD4+ T cells produced less IFN-γ in comparison with CD46D group (by 33% in HDs and by 43% in AEA) and were unable to upregulate IL-10 production following stimulation with αCD3/αCD46/IL-2/Calcitriol. Our results suggest the potential existence of a key for stratifying individuals suitable for calcitriol treatment in the context of low serum vitamin D levels. After validation in clinical studies, this key could be used as an adjunctive therapy not only for patients with allergic eosinophilic asthma, but also for other diseases.