Analysis of induced sputum in adults with asthma: identification of subgroup with isolated sputum neutrophilia and poor response to inhaled corticosteroids

Clinical characteristics of complete responders versus non-complete responders to omalizumab, benralizumab and mepolizumab in patients with severe asthma: a long-term retrospective analysis

BACKGROUND

Some patients with severe asthma may benefit from treatment with biologics, but evidence has been mostly collected from randomized controlled trials (RCTs), in which patients' characteristics are different from those encountered in asthma patients in the real-world setting. The aim of this study was to describe the clinical features of complete responders versus non-complete responders to long-term treatment with biologics in patients with severe asthma attended in routine daily practice.

METHODS

Data of a cohort of 90 patients with severe asthma who were treated with biologics (omalizumab, benralizumab, and mepolizumab) for at least 12 months and were followed up to March 2022. Data recorded included clinical characteristics and effectiveness of treatment (exacerbation, Asthma Control Test [ACT] score, lung function, use of maintenance oral corticosteroids [mOCS]), FeNO, and blood eosinophils at baseline, at 12 months, and at the end of follow-up. Complete response is considered if, in addition to not presenting exacerbations or the use of mOCS, the ACT score was >20 and, the FEV1 >80% predicted.

RESULTS

An improvement in all asthma control parameters was observed after 12 months of treatment and a mean follow-up of 55 months. After 12 months of treatment 27.2% of patients met the criteria of complete response and this percentage even increased to 35.3% at the end of follow-up. Long-term complete response was associated to better lung function with mepolizumab and omalizumab treatment and to less previous exacerbations in the benralizumab group. The main cause of not achieving a complete response was the persistence of an airflow obstructive pattern.

CONCLUSIONS

This study shows that omalizumab, benralizumab, and mepolizumab improved the clinical outcomes of patients with severe asthma in a clinic environment with similar effect sizes to RCTs in the long term follow-up. Airflow obstruction, however, was a predictor of a non-complete response to biologics.

Biomarkers in asthma, potential for therapeutic intervention

Asthma is a heterogeneous disease characterized by multiple phenotypes with varying risk factors and therapeutic responses. This Commentary describes research on biomarkers for T2-"high" and T2-"low" inflammation, a hallmark of the disease. Patients with asthma who exhibit an increase in airway T2 inflammation are classified as having T2-high asthma. In this endotype, Type 2 cytokines interleukins (IL)-4, IL-5, and IL-13, plus other inflammatory mediators, lead to increased eosinophilic inflammation and elevated fractional exhaled nitric oxide (FeNO). In contrast, T2-low asthma has no clear definition. Biomarkers are considered valuable tools as they can help identify various phenotypes and endotypes, as well as treatment response to standard treatment or potential therapeutic targets, particularly for biologics. As our knowledge of phenotypes and endotypes expands, biologics are increasingly integrated into treatment strategies for severe asthma. These treatments block specific inflammatory pathways or single mediators. While single or composite biomarkers may help to identify subsets of patients who might benefit from these treatments, only a few inflammatory biomarkers have been validated for clinical application. One example is sputum eosinophilia, a particularly useful biomarker, as it may suggest corticosteroid responsiveness or reflect non-compliance to inhaled corticosteroids. As knowledge develops, a meaningful goal would be to provide individualized care to patients with asthma.

Different bacterial cargo in apoptotic cells drive distinct macrophage phenotypes

The removal of dead cells (efferocytosis) contributes to the resolution of the infection and preservation of the tissue. Depending on the environment milieu, macrophages may show inflammatory (M1) or anti-inflammatory (M2) phenotypes. Inflammatory leukocytes are recruited during infection, followed by the accumulation of infected and non-infected apoptotic cells (AC). Efferocytosis of non-infected AC promotes TGF-β, IL-10, and PGE2 production and the polarization of anti-inflammatory macrophages. These M2 macrophages acquire an efficient ability to remove apoptotic cells that are involved in tissue repair and resolution of inflammation. On the other hand, the impact of efferocytosis of infected apoptotic cells on macrophage activation profile remains unknown. Here, we are showing that the efferocytosis of gram-positive Streptococcus pneumoniae-AC (Sp-AC) or gram-negative Klebsiella pneumoniae-AC (Kp-AC) promotes distinct gene expression and cytokine signature in macrophages. Whereas the efferocytosis of Kp-AC triggered a predominant M1 phenotype in vitro and in vivo, the efferocytosis of Sp-AC promoted a mixed M1/M2 activation in vitro and in vivo in a model of allergic asthma. Together, these findings suggest that the nature of the pathogen and antigen load into AC may have different impacts on inducing macrophage polarization.

Tezepelumab: patient selection and place in therapy in severe asthma

Asthma is a disease characterised by heterogeneous and multifaceted airway inflammation. Despite the availability of effective treatments, a substantial percentage of patients with the type 2 (T2)-high, but mainly the T2-low, phenotype complain of persistent symptoms, airflow limitation, and poor response to treatments. Currently available biologicals target T2 cytokines, but no monoclonal antibodies or other specific therapeutic options are available for non-T2 asthma. However, targeted therapy against alarmins is radically changing this perspective. The development of alarmin-targeted therapies, of which tezepelumab (TZP) is the first example, may offer broad action on inflammatory pathways as well as an enhanced therapeutic effect on epithelial dysfunction. In this regard, TZP demonstrated positive results not only in patients with severe T2 asthma but also those with non-allergic, non-eosinophilic disease. Therefore, it is necessary to identify clinical features of patients who can benefit from an upstream targeted therapy such as anti-thymic stromal lymphopoietin. The aims of this narrative review are to understand the role of alarmins in asthma pathogenesis and epithelial dysfunction, examine the rationale underlying the indication of TZP treatment in severe asthma, summarise the results of clinical studies, and recognise the specific characteristics of patients potentially eligible for TZP treatment.

Evidence for 2 clusters among patients with noneosinophilic asthma

BACKGROUND

Although asthma is often seen as an eosinophilic disease associated with atopy, patients with noneosinophilic asthma represent a substantial part of the population with asthma.

OBJECTIVE

To apply an unsupervised clustering method in a cohort of 588 patients with noneosinophilic asthma (sputum eosinophils < 3%) recruited from an asthma clinic of a secondary care center.

METHODS

Our cluster analysis of the whole cohort identified 2 subgroups as cluster 1 (n = 417) and cluster 2 (n = 171).

RESULTS

Cluster 1 comprised a predominantly female group with late disease onset, a low proportion of atopy (24%), and a substantial smoking history (53%). In this cluster, treatment burden was low (<50% of inhaled corticosteroid users); asthma control and quality of life were poor, with median Asthma Control Test, Asthma Control Questionnaire, and Asthma Quality of Life scores of 16, 1.7, and 4.5, respectively, whereas lung function was preserved with a median postbronchodilation forced expiratory volume in 1 second of 93% predicted. Cluster 2 was a predominantly male group, almost exclusively comprising patients with atopy (99%) with early disease onset and a moderate treatment burden (median inhaled corticosteroids dose 800 µg/d equivalent beclomethasone). In cluster 2, asthma was partially controlled, with median Asthma Control Test and Asthma Control Questionnaire scores reaching 18 and 1.3, respectively, and lung function well preserved with a median postbronchodilation of 95% predicted. Although systemic and airway neutrophilic inflammation was the dominant pattern in cluster 1, cluster 2 essentially comprised paucigranulocytic asthma with moderately elevated fraction exhaled nitric oxide.

CONCLUSION

Noneosinophilic asthma splits into 2 clusters distinguishing by disease onset, atopic status, smoking history, systemic and airway inflammation, and disease control and quality of life.

Neutrophil extracellular traps promote ΔNp63+ basal cell hyperplasia in chronic rhinosinusitis

BACKGROUND

Neutrophil extracellular traps (NETs) are observed in chronic rhinosinusitis (CRS), although their role remains unclear.

OBJECTIVES

This study aimed to investigate the influence of NETs on the CRS epithelium.

METHODS

Forty-five sinonasal biopsy specimens were immunofluorescence-stained to identify NETs and p63+ basal stem cells. Investigators treated human nasal epithelial cells with NETs and studied them with immunofluorescence staining, Western blotting, and quantitative real-time PCR. NET inhibitors were administered to a murine neutrophilic nasal polyp model.

RESULTS

NETs existed in tissues in patients with CRS with nasal polyps, especially in noneosinophilic nasal polyp tissues. p63+ basal cell expression had a positive correlation with the release of NETs. NETs induced the expansion of Ki-67+p63+ cells. We found that ΔNp63, an isoform of p63, was mainly expressed in the nasal epithelium and controlled by NETs. Treatment with deoxyribonuclease (DNase) I or Sivelestat (NET inhibitors) prevented the overexpression of ΔNp63+ epithelial stem cells and reduced polyp formation.

CONCLUSIONS

These results reveal that NETs are implicated in CRS pathogenesis via basal cell hyperplasia. This study suggests a novel possibility of treating CRS by targeting NETs.

Eosinophils-from cradle to grave: An EAACI task force paper on new molecular insights and clinical functions of eosinophils and the clinical effects of targeted eosinophil depletion

Over the past years, eosinophils have become a focus of scientific interest, especially in the context of their recently uncovered functions (e.g. antiviral, anti-inflammatory, regulatory). These versatile cells display both beneficial and detrimental activities under various physiological and pathological conditions. Eosinophils are involved in the pathogenesis of many diseases which can be classified into primary (clonal) and secondary (reactive) disorders and idiopathic (hyper)eosinophilic syndromes. Depending on the biological specimen, the eosinophil count in different body compartments may serve as a biomarker reflecting the underlying pathophysiology and/or activity of distinct diseases and as a therapy-driving (predictive) and monitoring tool. Personalized selection of an appropriate therapeutic strategy directly or indirectly targeting the increased number and/or activity of eosinophils should be based on the understanding of eosinophil homeostasis including their interactions with other immune and non-immune cells within different body compartments. Hence, restoring as well as maintaining homeostasis within an individual's eosinophil pool is a goal of both specific and non-specific eosinophil-targeting therapies. Despite the overall favourable safety profile of the currently available anti-eosinophil biologics, the effect of eosinophil depletion should be monitored from the perspective of possible unwanted consequences.

BALB/c and C57BL/6 mice differ in oxidant and antioxidant responses in innate and adaptive immune cells in an asthma model induced by cockroach allergens

Asthma is a complex and heterogenous disease affected by a multitude of factors. Several phenotypes of asthma exist which are influenced by various molecular mechanisms that include presence of antioxidant and oxidant enzymes in different immune cells such as dendritic cells (DCs), alveolar macrophages (AMs), neutrophils, and T cells. Close interaction between epithelial cells and dendritic cells initiates complex pathogenesis of asthma followed by involvement of other innate and adaptive immune cells. In chronic phase of the disease, these immune cells support each other in amplification of airway inflammation where oxidant-antioxidant balance is known to be an important contributing factor. Genetic variability in antioxidant response may influence the development of airway inflammation, however it has not been studied in mice yet. The two most studied mice strains, i.e. BALB/c and C57BL/6 are reported to have dissimilar airway responses to the same allergens due to their genetic makeup. In this investigation, we explored whether these strains had any differences in pulmonary oxidant-antioxidant system (Nrf2, SOD2, iNOS, HO-1, nitrotyrosine) in different immune cells (DCs, AMs, neutrophils, T cells), airway inflammation (presence of eosinophils and/or neutrophils) and mucus production in response to repeated cockroach allergen extract (CE) mouse model of asthma. Our data show that C57BL/6 mice had better induction of antioxidant system than BALB/c mice. Consequently, iNOS/nitrotyrosine levels were much exaggerated in BALB/c than C57BL/6 mice. As a result, BALB/c mice developed mixed granulocytic airway inflammation, whereas C57BL/6 developed mostly eosinophilic airway inflammation. Our data suggest that an exaggerated oxidant generation along with a weak antioxidant induction in response to a natural allergen on a susceptible genetic background may determine development of severe asthma phenotype such as mixed granulocyte inflammation.

Early-immune development in asthma: A review of the literature

This review presents a comprehensive examination of the various factors contributing to the immunopathogenesis of asthma from the prenatal to preschool period. We focus on the contributions of genetic and environmental components as well as the role of the nasal and gut microbiome on immune development. Predisposing genetic factors, including inherited genes associated with increased susceptibility to asthma, are discussed alongside environmental factors such as respiratory viruses and pollutant exposure, which can trigger or exacerbate asthma symptoms. Furthermore, the intricate interplay between the nasal and gut microbiome and the immune system is explored, emphasizing their influence on allergic immune development and response to environmental stimuli. This body of literature underscores the necessity of a comprehensive approach to comprehend and manage asthma, as it emphasizes the interactions of multiple factors in immune development and disease progression.

Sputum induction and its diagnostic applications in inflammatory airway disorders: a review

Sputum induction is a technique that covers the induction and the subsequent processing of the expectorate primarily for the analysis of cells and different inflammatory biomarkers present in the airways to further understand the pathophysiology of different inflammatory respiratory disorders such as asthma and chronic obstructive pulmonary disease (COPD) as well as the diagnosis of lung diseases such as lung cancer, tuberculosis, and Pneumocystis jirovecii pneumonia. It is a non-invasive, safe, cost-effective, and reliable technique reported to exhibit a high success rate. However, due to being technically demanding and time-consuming and having the need of employing trained staff, this technique is only used in restricted research centres and in limited centres of clinical use. When the sputum is collected after induction, the primary goal is to obtain a differential cell count and evaluate the molecular biomarkers of airway inflammation such as eosinophil cationic protein, eosinophil-derived neurotoxin, major basic protein, tryptase, cytokine production [e.g., interleukin (IL)-5], albumin, and fibrinogen. In addition, cytospins from the processed sputum are used for immunocytochemical staining of cellular products such as EG-2 reactive protein, granulocyte-macrophage colony-stimulating factor, tumour necrosis factor alpha, and IL-8 that play significant roles in understanding the pathophysiology of inflammatory airway diseases. Nowadays, this technique can be further used by performing an additional analysis such as flow cytometry and in situ hybridisation on the sputum supernatant to investigate more the immune response and pathophysiological process of such various respiratory diseases. In addition, the application of sputum fluid phase to assess the biomarkers could be used more routinely in pathological laboratories for diagnosing lung cancer, COPD, and asthma as well as for monitoring lung cancer progression and asthma and COPD treatment, allowing for early detection and a better treatment provided by the clinicians.

The Dual Role of the Airway Epithelium in Asthma: Active Barrier and Regulator of Inflammation

Chronic airway inflammation is the cornerstone on which bronchial asthma arises, and in turn, chronic inflammation arises from a complex interplay between environmental factors such as allergens and pathogens and immune cells as well as structural cells constituting the airway mucosa. Airway epithelial cells (AECs) are at the center of these processes. On the one hand, they represent the borderline separating the body from its environment in order to keep inner homeostasis. The airway epithelium forms a multi-tiered, self-cleaning barrier that involves an unstirred, discontinuous mucous layer, the dense and rigid mesh of the glycocalyx, and the cellular layer itself, consisting of multiple, densely interconnected cell types. On the other hand, the airway epithelium represents an immunologically highly active tissue once its barrier has been penetrated: AECs play a pivotal role in releasing protective immunoglobulin A. They express a broad spectrum of pattern recognition receptors, enabling them to react to environmental stressors that overcome the mucosal barrier. By releasing alarmins-proinflammatory and regulatory cytokines-AECs play an active role in the formation, strategic orientation, and control of the subsequent defense reaction. Consequently, the airway epithelium is of vital importance to chronic inflammatory diseases, such as asthma.

Identification of cough-variant asthma phenotypes based on clinical and pathophysiologic data

BACKGROUND

Cough-variant asthma (CVA) may respond differently to antiasthmatic treatment. There are limited data on the heterogeneity of CVA.

OBJECTIVE

We aimed to classify patients with CVA using cluster analysis based on clinicophysiologic parameters and to unveil the underlying molecular pathways of these phenotypes with transcriptomic data of sputum cells.

METHODS

We applied k-mean clustering to 342 newly physician-diagnosed patients with CVA from a prospective multicenter observational cohort using 10 prespecified baseline clinical and pathophysiologic variables. The clusters were compared according to clinical features, treatment response, and sputum transcriptomic data.

RESULTS

Three stable CVA clusters were identified. Cluster 1 (n = 176) was characterized by female predominance, late onset, normal lung function, and a low proportion of complete resolution of cough (60.8%) after antiasthmatic treatment. Patients in cluster 2 (n = 105) presented with young, nocturnal cough, atopy, high type 2 inflammation, and a high proportion of complete resolution of cough (73.3%) with a highly upregulated coexpression gene network that related to type 2 immunity. Patients in cluster 3 (n = 61) had high body mass index, long disease duration, family history of asthma, low lung function, and low proportion of complete resolution of cough (54.1%). TH17 immunity and type 2 immunity coexpression gene networks were both upregulated in clusters 1 and 3.

CONCLUSION

Three clusters of CVA were identified with different clinical, pathophysiologic, and transcriptomic features and responses to antiasthmatics treatment, which may improve our understanding of pathogenesis and help clinicians develop individualized cough treatment in asthma.

Type 2 Low Biomarker Stability and Exacerbations in Severe Uncontrolled Asthma

We investigated the stability of T2 low status, based on low levels of T2 biomarkers, and exacerbation rates in T2 low and non-T2 low asthma from clinical retrospective data of severe uncontrolled asthma patients. Knowledge of the T2 low biomarker profile is sparse and biomarker stability is uncharted. Secondary care patients with severe uncontrolled asthma and at least two blood eosinophil counts (BEC) and fractional exhaled nitric oxide (FeNO) measured for determination of type 2 inflammation status were evaluated from a follow-up period of 4 years. Patients were stratified into four groups: T2 low₁₅₀ (n = 31; BEC < 150 cells/µL and FeNO < 25 ppb), non-T2 low₁₅₀ (n = 138; BEC > 150 cells/µL and/or FeNO > 25 ppb), T2 low₃₀₀ (n = 66; BEC < 300 cells/µL and FeNO < 25 ppb), and non-T2 low₃₀₀ (n = 103; BEC > 300 cells/µL and/or FeNO > 25 ppb). Exacerbation rates requiring hospital care, stability of biomarker status, and cumulative OCS and ICS doses were assessed during follow-up. Among patients with severe uncontrolled asthma, 18% (n = 31) were identified as T2 low₁₅₀, and 39% (n = 66) as T2 low₃₀₀. In these groups, the low biomarker profile was stable in 55% (n = 11) and 72% (n = 33) of patients with follow-up measures. Exacerbation rates were different between the T2 low and non-T2 low groups: 19.7 [95% CI: 4.3-45.6] in T2 low₁₅₀ vs. 8.4 [4.7-13.0] in non-T2 low₁₅₀ per 100 patient-years. BEC and FeNO are useful biomarkers in identifying T2 low severe uncontrolled asthma, showing a stable follow-up biomarker profile in up to 72% of patients. Repeated monitoring of these biomarkers is essential in identifying and treating patients with T2 low asthma.

COVID-19 and chronic rhinosinusitis: management and comorbidity - what have we learned?

INTRODUCTION

Approximately 5%-12% of the population worldwide suffer from chronic rhinosinusitis (CRS). CRS is defined as a chronic respiratory disease and is considered to be a risk factor for COVID-19 patients.

AREAS COVERED

A non-systematic literature research was conducted on COVID-19 and treatment options for CRSwNP. The latest international publications in medical databases, international guidelines, and the internet were reviewed. Since there were no publications on all aspects of this topic during the pandemic, we included our own experience in this report. Based on the conducted literature research in addition to our previously reported experience, we discuss the treatment of CRSwNP during the COVID-19 pandemic and what can be taken for future pandemics.

EXPERT OPINION

Intranasal corticosteroids remain the standard treatment for CRS in patients with SARS-CoV-2 infection. Indications for surgical treatment of CRS should be critically evaluated and reserved for patients with complications and those with no other treatment options. For this purpose, COVID-19 status should be known if possible and, in case of unclear status (emergency), using appropriate personal protective equipment. Systemic corticosteroids should be avoided were possible. Biological treatment should be continued under careful monitoring in uninfected patients and should be temporarily interrupted during COVID-19 infection.

Airway hyperresponsiveness reflects corticosteroid-sensitive mast cell involvement across asthma phenotypes

BACKGROUND

Airway hyperresponsiveness is a hallmark of asthma across asthma phenotypes. Airway hyperresponsiveness to mannitol specifically relates to mast cell infiltration of the airways, suggesting inhaled corticosteroids to be effective in reducing the response to mannitol, despite low levels of type 2 inflammation.

OBJECTIVE

We sought to investigate the relationship between airway hyperresponsiveness and infiltrating mast cells, and the response to inhaled corticosteroid treatment.

METHODS

In 50 corticosteroid-free patients with airway hyperresponsiveness to mannitol, mucosal cryobiopsies were obtained before and after 6 weeks of daily treatment with 1600 μg of budesonide. Patients were stratified according to baseline fractional exhaled nitric oxide (Feno) with a cutoff of 25 parts per billion.

RESULTS

Airway hyperresponsiveness was comparable at baseline and improved equally with treatment in both patients with Feno-high and Feno-low asthma: doubling dose, 3.98 (95% CI, 2.49-6.38; P < .001) and 3.85 (95% CI, 2.51-5.91; P < .001), respectively. However, phenotypes and distribution of mast cells differed between the 2 groups. In patients with Feno-high asthma, airway hyperresponsiveness correlated with the density of chymase-high mast cells infiltrating the epithelial layer (ρ, -0.42; P = .04), and in those with Feno-low asthma, it correlated with the density in the airway smooth muscle (ρ, -0.51; P = .02). The improvement in airway hyperresponsiveness after inhaled corticosteroid treatment correlated with a reduction in mast cells, as well as in airway thymic stromal lymphopoietin and IL-33.

CONCLUSIONS

Airway hyperresponsiveness to mannitol is related to mast cell infiltration across asthma phenotypes, correlating with epithelial mast cells in patients with Feno-high asthma and with airway smooth muscle mast cells in patients with Feno-low asthma. Treatment with inhaled corticosteroids was effective in reducing airway hyperresponsiveness in both groups.

Cytokine-targeted therapies for asthma and COPD

Asthma affects over 300 million people worldwide and its prevalence is increasing. COPD is the third leading cause of death globally. Asthma and COPD are complex inflammatory diseases of the airways in which impaired host defences lead to increased susceptibility to pathogens, pollutants and allergens. There is a constant interplay between host and the environment. Environmental exposures can alter the lung microbiome and influence the development of sensitisation by disrupting normal immunoregulation. The underlying airway inflammation in severe asthma is heterogeneous, with upregulation of type 2 cytokines in most cases but increased neutrophilic inflammation and activated T-helper 17 mediated immunity in others. COPD may also comprise several different phentoypes that are driven by different molecular mechanisms or endotypes. This disease heterogeneity is affected by comorbidities, treatments and environmental exposures. Recent intervention trials have shed light on the pathways beyond type 2 inflammation that can lead to beneficial outcomes versus potentially deleterious effects. We have made a great deal of progress over the last 10 years in terms of immunology and the pathophysiology of asthma and this has led to the development of novel treatments and major improvements in severe asthma outcomes. In COPD, however, no targeted treatments have demonstrated great improvements. This article reviews the mechanism of action and efficacy of the available biologics in asthma and COPD.

IL-22 Is Deleterious along with IL-17 in Allergic Asthma but Is Not Detrimental in the Comorbidity Asthma and Acute Pneumonia

There is evidence that IL-22 and IL-17 participate in the pathogenesis of allergic asthma. To investigate the role of IL-22, we used IL-22 deficient mice (IL-22 KO) sensitized and challenged with ovalbumin (OVA) and compared with wild type (WT) animals exposed to OVA. IL-22 KO animals exposed to OVA showed a decreased number and frequency of eosinophils, IL-5 and IL-13 in the airways, reduced mucus production and pulmonary inflammation. In addition, IL-22 KO animals exhibited a decreased percentage and number of lung CD11c+CD11b+ cells and increased apoptosis of eosinophils. Th17 cell transfer generated from IL-22 KO to animals previously sensitized and challenged with OVA caused a reduction in eosinophil frequency and number in the airways compared to animals transferred with Th17 cells generated from WT mice. Therefore, IL-22 is deleterious with concomitant secretion of IL-17. Our findings show a pro-inflammatory role for IL-22, confirmed in a model of allergen-free and allergen-specific immunotherapy. Moreover, during the comorbidity asthma and pneumonia that induces neutrophil inflammation, IL-22 was not detrimental. Our results show that targeting IL-22 would negatively affect the survival of eosinophils, reduce the expansion or migration of CD11c+CD11b+ cells, and negatively regulate allergic asthma.

Elevated Neutrophil-to-Lymphocyte Ratio Is Associated with Severe Asthma Exacerbation in Children

Asthma is the most common chronic respiratory disease in children. The neutrophil-to-lymphocyte ratio (NLR) is a marker of a chronic inflammatory state; however, data on the association of NLR with acute asthma exacerbations in children is lacking. In this cross-sectional study, between 2016 and 2021, children aged 2-18 years who were referred to the emergency department (ED) due to asthma exacerbation, were included. NLR, calculated from complete blood count upon arrival, was assessed as a continuous variable and was classified into four groups according to quartiles. The association between severity parameters and NLR quartiles was examined. A total of 831 ED visits for asthma exacerbation were included in the study. The median NLR was 1.6, 3.8, 6.7, and 12.9 in quartiles 1-4, respectively (p < 0.001). Demographic parameters, background diseases, and chronic medications were similar between the quartiles. Higher heart rate, body temperature, systolic blood pressure, and respiratory rate were observed in the higher NLR quartiles, as well as lower oxygen saturation. Higher urgency scale and higher rates of intravenous magnesium sulfate were observed in the higher NLR quartiles, with higher admission rates and prolonged hospitalizations. In summary, NLR upon admission is associated with the severity of asthma exacerbation and higher chances of hospitalization among children in the ED.

Regulation of c-SMAC formation and AKT-mTOR signaling by the TSG101-IFT20 axis in CD4+ T cells

CD4⁺ T cells play major roles in the adaptive immune system, which requires antigen recognition, costimulation, and cytokines for its elaborate orchestration. Recent studies have provided new insight into the importance of the supramolecular activation cluster (SMAC), which comprises concentric circles and is involved in the amplification of CD4⁺ T cell activation. However, the underlying mechanism of SMAC formation remains poorly understood. Here, we performed single-cell RNA sequencing of CD4⁺ T cells left unstimulated and stimulated with anti-CD3 and anti-CD28 antibodies to identify novel proteins involved in their regulation. We found that intraflagellar transport 20 (IFT20), previously known as cilia-forming protein, was upregulated in antibody-stimulated CD4⁺ T cells compared to unstimulated CD4⁺ T cells. We also found that IFT20 interacted with tumor susceptibility gene 101 (TSG101), a protein that endocytoses ubiquitinated T-cell receptors. The interaction between IFT20 and TSG101 promoted SMAC formation, which led to amplification of AKT-mTOR signaling. However, IFT20-deficient CD4⁺ T cells showed SMAC malformation, resulting in reduced CD4⁺ T cell proliferation, aerobic glycolysis, and cellular respiration. Finally, mice with T-cell-specific IFT20 deficiency exhibited reduced allergen-induced airway inflammation. Thus, our data suggest that the IFT20-TSG101 axis regulates AKT-mTOR signaling via SMAC formation.

The Airway Microbiome-IL-17 Axis: a Critical Regulator of Chronic Inflammatory Disease

The respiratory tract is home to a diverse microbial community whose influence on local and systemic immune responses is only beginning to be appreciated. Increasing reports have linked changes in this microbiome to a range of pulmonary and extrapulmonary disorders, including asthma, chronic obstructive pulmonary disease and rheumatoid arthritis. Central to many of these findings is the role of IL-17-type immunity as an important driver of inflammation. Despite the crucial role played by IL-17-mediated immune responses in protection against infection, overt Th17 cell responses have been implicated in the pathogenesis of several chronic inflammatory diseases. However, our knowledge of the influence of bacteria that commonly colonise the respiratory tract on IL-17-driven inflammatory responses remains sparse. In this article, we review the current knowledge on the role of specific members of the airway microbiota in the modulation of IL-17-type immunity and discuss how this line of research may support the testing of susceptible individuals and targeting of inflammation at its earliest stages in the hope of preventing the development of chronic disease.

Aging-Related Mechanisms Contribute to Corticosteroid Insensitivity in Elderly Asthma

Asthma in elderly populations is an increasing health problem that is accompanied by diminished lung function and frequent exacerbations. As potent anti-inflammatory drugs, corticosteroids are commonly used to reduce lung inflammation, improve lung function, and manage disease symptoms in asthma. Although effective for most individuals, older patients are more insensitive to corticosteroids, making it difficult to manage asthma in this population. With the number of individuals older than 65 continuing to increase, it is important to understand the distinct mechanisms that promote corticosteroid insensitivity in the aging lung. In this review, we discuss corticosteroid insensitivity in asthma with an emphasis on mechanisms that contribute to persistent inflammation and diminished lung function in older individuals.

Endocrine-disrupting chemical exposure augments neutrophilic inflammation in severe asthma through the autophagy pathway

Corticosteroid resistance, progressive lung function decline, and frequent asthma exacerbations are the hallmarks of neutrophilic asthma (NA). However, the potential contributors and their mechanisms of NA aggravation have not yet been fully clarified. This study was conducted to assess the precise mechanism and inflammatory effects of endocrine-disrupting chemicals using mono-n-butyl phthalate (MnBP) on an NA model. BALB/c mice from normal control and LPS/OVA-induced NA groups were treated with or without MnBP. The effects of MnBP on the airway epithelial cells (AECs), macrophages (Mφ), and neutrophils were investigated in vitro and in vivo. NA mice exposed to MnBP had significantly increased airway hyperresponsiveness, total and neutrophil cell counts in the bronchoalveolar lavage fluid, and the percentage of M1Mφ in the lung tissues compared to those non-exposed to MnBP. In in vitro study, MnBP induced the human neutrophil activation to release neutrophil DNA extracellular traps, Mφ polarizing toward M1Mφ, and AEC damage. Treatment with hydroxychloroquine (an autophagy inhibitor) reduced the effects of MnBP in vivo and in vitro. The results of our study suggest that MnBP exposure may increase the risk of neutrophilic inflammation in severe asthma and autophagy pathway-targeted therapeutics can help control MnBP-induced harmful effects in asthma.

Bruton's tyrosine kinase inhibition suppresses neutrophilic inflammation and restores histone deacetylase 2 expression in myeloid and structural cells in a mixed granulocytic mouse model of asthma

Asthmatic inflammation is not a single homogenous inflammation but may be categorized into several phenotypes/endotypes. Severe asthma is characterized by mixed granulocytic inflammation in which there is increased presence of neutrophilic numbers and unresponsiveness to corticosteroids. Neutrophilic oxidative stress and histone deacetylase 2 (HDAC2) dysregulation in the pulmonary compartment are thought to lead to corticosteroid insensitivity in severe asthma with mixed granulocytic inflammation. Bruton's tyrosine kinase (BTK) is a no-receptor tyrosine kinase which is expressed in innate immune cells such as neutrophils and dendritic cells (DCs) where it is incriminated in balancing of inflammatory signaling. We hypothesized in this study that BTK inhibition strategy could be utilized to restore corticosteroid responsiveness in mixed granulocytic asthma. Therefore, combined therapy of BTK inhibitor (ibrutinib) and corticosteroid, dexamethasone was administered in cockroach allergen extract (CE)-induced mixed granulocyte airway inflammation model in mice. Our data show that CE-induced neutrophilic inflammation was concomitant with HDAC2 expression and upregulation of p-NFkB expression in airway epithelial cells (AECs), myeloid cells and pulmonary tissue. Further, there were increased expression/release of inflammatory and oxidative mediators such as MUC5AC, TNF-α, GM-CSF, MCP-1, iNOS, nitrotyrosine, MPO, lipid peroxides in AECs/myeloid cells/pulmonary tissue. Dexamethasone alone significantly attenuated eosinophilic inflammation and inflammatory cytokines but was not able to control oxidative inflammation. Ibrutinib alone markedly reduced neutrophilic infiltration and oxidative inflammation, and restored HDAC2 without having any significant effect on eosinophilic inflammation. These data suggest that BTK inhibition strategy may be used in conjunction with dexamethasone to treat both neutrophilic and eosinophilic inflammation, i.e. mixed granulocytic asthma.

Asthma-associated bacterial infections: Are they protective or deleterious?

Eosinophilic, noneosinophilic, or mixed granulocytic inflammations are the hallmarks of asthma heterogeneity. Depending on the priming of lung immune and structural cells, subjects with asthma might generate immune responses that are TH2-prone or TH17-prone immune response. Bacterial infections caused by Haemophilus, Moraxella, or Streptococcus spp. induce the secretion of IL-17, which in turn recruit neutrophils into the airways. Clinical studies and experimental models of asthma indicated that neutrophil infiltration induces a specific phenotype of asthma, characterized by an impaired response to corticosteroid treatment. The understanding of pathways that regulate the TH17-neutrophils axis is critical to delineate and develop host-directed therapies that might control asthma and its exacerbation episodes that course with infectious comorbidities. In this review, we outline clinical and experimental studies on the role of airway epithelial cells, S100A9, and high mobility group box 1, which act in concert with the IL-17-neutrophil axis activated by bacterial infections, and are related with asthma that is difficult to treat. Furthermore, we report critically our view in the light of these findings in an attempt to stimulate further investigations and development of immunotherapies for the control of severe asthma.

Targeting the Semaphorin3E-plexinD1 complex in allergic asthma

Asthma is a heterogenous airway disease characterized by airway inflammation and remodeling. It affects more than 300 million people worldwide and poses a significant burden on society. Semaphorins, discovered initially as neural guidance molecules, are ubiquitously expressed in various organs and regulate multiple signaling pathways. Interestingly, Semaphorin3E is a critical molecule in lung pathophysiology through its role in both lung development and homeostasis. Semaphorin3E binds to plexinD1, mediating regulatory effects on cell migration, proliferation, and angiogenesis. Recent in vitro and in vivo studies have demonstrated that the Semaphorin3E-plexinD1 axis is implicated in asthma, impacting inflammatory and structural cells associated with airway inflammation, tissue remodeling, and airway hyperresponsiveness. This review details the Semaphorin3E-plexinD1 axis in various aspects of asthma and highlights future directions in research including its potential role as a therapeutic target in airway allergic diseases.

Pediatric obesity and severe asthma: Targeting pathways driving inflammation

Asthma affects more than 300 million people of all ages worldwide, including about 10-15% of school-aged children, and its prevalence is increasing. Severe asthma (SA) is a particular and rare phenotype requiring treatment with high-dose inhaled corticosteroids plus a second controller and/or systemic glucocorticoid courses to achieve symptom control or remaining "uncontrolled" despite this therapy. In SA, other diagnoses have been excluded, and potential exacerbating factors have been addressed. Notably, obese asthmatics are at higher risk of developing SA. Obesity is both a major risk factor and a disease modifier of asthma in children and adults: two main "obese asthma" phenotypes have been described in childhood with high or low levels of Type 2 inflammation biomarkers, respectively, the former characterized by early onset and eosinophilic inflammation and the latter by neutrophilic inflammation and late-onset. Nevertheless, the interplay between obesity and asthma is far more complex and includes obese tissue-driven inflammatory pathways, mechanical factors, comorbidities, and poor response to corticosteroids. This review outlines the most recent findings on SA in obese children, particularly focusing on inflammatory pathways, which are becoming of pivotal importance in order to identify selective targets for specific treatments, such as biological agents.

Characteristics of Induced-Sputum Inflammatory Phenotypes in Adults with Asthma: Predictors of Bronchial Eosinophilia

Purpose

The objectives of this study were, for patients attending a specialist asthma clinic at a tertiary care hospital, to determine, from sputum induction (SI), proportions of bronchial inflammatory phenotypes, demographic, clinical and functional characteristics of each phenotype, and the most accessible non-invasive inflammatory marker that best discriminates between phenotypes.

Patients and Methods

Included were 96 patients with asthma, attending a specialist asthma clinic at a tertiary care hospital, who underwent testing as follows: SI, spirometry, fractional exhaled nitric oxide (FeNO), blood eosinophilia, total immunoglobulin E (IgE), and a skin prick test.

Results

SI phenotypes were 46.9% eosinophilic, 33.3% paucigranulocytic, 15.6% neutrophilic, and 4.2% mixed. No significantly different clinical or functional characteristics were observed between the phenotypes. A positive correlation was observed between SI eosinophilia and both emergency visits in the last 12 months (p = 0.041; r = 0.214) and FeNO values (p = 0.000; r = 0.368). Blood eosinophilia correlated with SI eosinophilia (p = 0.001; r = 0.362) and was the best predictor of bronchial eosinophilia, followed by FeNO, and total blood IgE (area under the receiver operating characteristic curve (AUC-ROC) 72%, 65%, and 53%, respectively), although precision was only fair.

Conclusion

In consultations for severe asthma, the most frequent phenotype was eosinophilic. Peripheral blood eosinophilia is a reliable marker for discriminating between different bronchial inflammatory phenotypes, is useful in enabling doctors to select a suitable biologic treatment and so prevent asthma exacerbation, and is a better predictor of bronchial eosinophilia than FeNO and IgE values.

Heterogeneity of Treatment Response to Asthma

The definition of asthma has evolved over the years with significant heterogeneity of the disease increasingly recognized. Complex gene and environment interactions result in different pheno-endotypes of asthma that respond differently to the same treatment. Multiple studies have revealed pharmacogenomic and endophenotypic factors that predict treatment response to standard therapies for asthma. Recent advances in biologic medications have enabled a more tailored approach to the care of patients with moderate to severe asthma, taking into consideration clinical traits and measurable biomarkers. This chapter will review heterogeneity in treatment response to different medication classes for asthma: inhaled and systemic corticosteroids, beta-2 agonists, leukotriene modifiers, muscarinic antagonists, macrolides, and biologics.

HLA-G in asthma and its potential as an effective therapeutic agent

OBJECTIVE

Asthma is a heterogeneous disease. Severity of asthma and sensitivity to medications vary across asthma subtypes. Human leukocyte antigen (HLA)-G has a wide range of functions in normal and pathological physiology. Due to its powerful immune function, HLA-G participates in the pathogenesis of different asthma phenotypes by regulating the activity and function of various immune cells. The mechanism of HLA-G in asthma is not fully clear, and there is no consensus on its mechanism in asthma. Further studies are needed to explore the role of HLA-G in different phenotypes of human asthma.

METHODS

Observational study.

RESULTS

HLA-G is an important immunomodulatory factor in asthma. Studies have found different levels of HLA-G in patients with different asthma subtypes and healthy controls, but other studies have come to the opposite conclusion.

CONCLUSION

We speculate that further study on the mechanism of HLA-G in asthma pheno-types may explain some of the contradictions in current studies. Findings should provide information regarding the potential of HLA-G as a novel target for asthma diagnosis and treatment.

Biomarkers in severe asthma: Identifying the treatable trait

Asthma is a chronic condition of bronchial hyper-reactivity associated with inflammation ranges from mild to severe form. It affects 1 - 18% of the population globally and it is estimated that > 300million people in the world have asthma. Of this 5 - 10% have severe asthma. while the proportion of patients suffering from severe are smaller, the morbidity and mortality are higher in this group. With the advances in our understanding of the pathophysiology of asthma there is a need to understand the role of various biomarkers. We live in an era of precision medicine and today there is a clear unmet need to understand targeted therapies. This review aims to raise awareness to the available biomarkers used in clinical practice in India and their role in predicting response to targeted therapies.

Physical training in adults with asthma: An integrative approach on strategies, mechanisms, and benefits

Asthma is a chronic airway disease characterized by airflow limitation and respiratory symptoms associated with chronic airway and systemic inflammation, bronchial hyperreactivity (BHR), and exercise-induced bronchoconstriction (EIB). Asthma is a heterogeneous disease classified according to distinct airway and systemic inflammation. Patients commonly present with several comorbidities, including anxiety, depression, poor sleep quality, and reduced physical activity levels. Individuals with moderate to severe asthma often have more symptoms and difficulty achieving adequate clinical control, which is associated with poor quality of life, despite proper pharmacological treatment. Physical training has been proposed as an adjunctive therapy for asthma. Initially, it was suggested that the effect of physical training might be attributed to the improved oxidative capacity and reduced production of exercise metabolites. However, in the last decade, there has been evidence that aerobic physical training promotes anti-inflammatory effects in asthma patients. Physical training improves BHR and EIB, asthma symptoms, clinical control, anxiety, and depression levels, sleep quality, lung function, exercise capacity, and dyspnea perception. Furthermore, physical training reduces medication consumption. The most commonly used exercise strategies are moderate aerobic and breathing exercises; however, other techniques, such as high-intensity interval training, have shown promising effects. In the present study, we reviewed the strategies and beneficial effects of exercise on clinical and pathophysiological asthma outcomes.

Different Impacts of Blood and Sputum Eosinophil Counts on Lung Function and Clinical Outcomes in Asthma: Findings from the COREA Cohort

PURPOSE

Blood (EOS-B) and sputum (EOS-S) eosinophil counts may contribute differently to asthma pathogenesis. We compared the impact of the baseline EOS-B and EOS-S levels on lung function, asthma control, and exacerbation in Korean asthma patients.

METHODS

Asthma patients with baseline EOS-B (n = 4257) and EOS-S (n = 1049) levels from a multicenter cohort (COREA) were included. Pulmonary function test (%FEV1 predicted), asthma control test (ACT), and asthma exacerbation incidence were followed-up every 3 months for one year. Linear mixed-effect models and survival analyses were used to examine the association between eosinophilic groups defined by EOS-B or EOS-S and outcomes.

RESULTS

High eosinophilic groups were associated with a low baseline value and a high improvement in the %FEV1 predicted and ACT scores over time. The magnitude of group difference in %FEV1 predicted was twofold higher in the EOS-S versus EOS-B classification [mean and 95% CI: 4.7 (0.6-8.8) versus 2.0 (0.2-3.7) for the baseline value and - 1.5 (- 2.3 to - 0.8) versus - 0.8(- 1.1 to -0.4) for the slope of change], whereas it was identical in ACT score. The magnitude of the impact increased linearly with the elevation of the cut-off level for the EOS-B but remained stable for the EOS-S classification. Patients with an elevation of both their EOS-B and EOS-S showed a higher increment in the %FEV1 predicted and ACT over time. Neither the EOS-B nor EOS-S was associated with asthma exacerbation.

CONCLUSION

EOS-S and EOS-B contribute differently to the clinical outcomes and should be taken into account independently to improve asthma care.

Relationship between inflammatory status and microbial composition in severe asthma and during exacerbation

BACKGROUND

In T2-mediated severe asthma, biologic therapies, such as mepolizumab, are increasingly used to control disease. Current biomarkers can indicate adequate suppression of T2 inflammation, but it is unclear whether they provide information about airway microbial composition. We investigated the relationships between current T2 biomarkers and microbial profiles, characteristics associated with a Proteobacteria^HIGH microbial profile and the effects of mepolizumab on airway ecology.

METHODS

Microbiota sequencing was performed on sputum samples obtained at stable and exacerbation state from 140 subjects with severe asthma participating in two clinical trials. Inflammatory subgroups were compared on the basis of biomarkers, including FeNO and sputum and blood eosinophils. Proteobacteria^HIGH subjects were identified by Proteobacteria to Firmicutes ratio ≥0.485. Where paired sputum from stable visits was available, we compared microbial composition at baseline and following ≥12 weeks of mepolizumab.

RESULTS

Microbial composition was not related to inflammatory subgroup based on sputum or blood eosinophils. FeNO ≥50 ppb when stable and at exacerbation indicated a group with less dispersed microbial profiles characterised by high alpha-diversity and low Proteobacteria. Proteobacteria^HIGH subjects were neutrophilic and had a longer time from asthma diagnosis than Proteobacteria^LOW subjects. In those studied, mepolizumab did not alter airway bacterial load or lead to increased Proteobacteria.

CONCLUSION

High FeNO could indicate a subgroup of severe asthma less likely to benefit from antimicrobial strategies at exacerbation or in the context of poor control. Where FeNO is <50 ppb, biomarkers of microbial composition are required to identify those likely to respond to microbiome-directed strategies. We found no evidence that mepolizumab alters airway microbial composition.

Critical evaluation of asthma biomarkers in clinical practice

The advent of personalized medicine has revolutionized the whole approach to the management of asthma, representing the essential basis for future developments. The cornerstones of personalized medicine are the highest precision in diagnosis, individualized prediction of disease evolution, and patient-tailored treatment. To this aim, enormous efforts have been established to discover biomarkers able to predict patients' phenotypes according to clinical, functional, and bio-humoral traits. Biomarkers are objectively measured characteristics used as indicators of biological or pathogenic processes or clinical responses to specific therapeutic interventions. The diagnosis of type-2 asthma, prediction of response to type-2 targeted treatments, and evaluation of the risk of exacerbation and lung function impairment have been associated with biomarkers detectable either in peripheral blood or in airway samples. The surrogate nature of serum biomarkers, set up to be less invasive than sputum analysis or bronchial biopsies, has shown several limits concerning their clinical applicability. Routinely used biomarkers, like peripheral eosinophilia, total IgE, or exhaled nitric oxide, result, even when combined, to be not completely satisfactory in segregating different type-2 asthma phenotypes, particularly in the context of severe asthma where the choice among different biologics is compelling. Moreover, the type-2 low fraction of patients is not only an orphan of biological treatments but is at risk of being misdiagnosed due to the low negative predictive value of type-2 high biomarkers. Sputum inflammatory cell analysis, considered the highest specific biomarker in discriminating eosinophilic inflammation in asthma, and therefore elected as the gold standard in clinical trials and research models, demonstrated many limits in clinical applicability. Many factors may influence the measure of these biomarkers, such as corticosteroid intake, comorbidities, and environmental exposures or habits. Not least, biomarkers variability over time is a confounding factor leading to wrong clinical choices. In this narrative review, we try to explore many aspects concerning the role of routinely used biomarkers in asthma, applying a critical view over the "state of the art" and contemporarily offering an overview of the most recent evidence in this field.

Recent advances in the treatment of childhood asthma: a clinical pharmacology perspective

INTRODUCTION

Childhood asthma is a complex heterogenous inflammatory disease that can pose a large burden on patients and their caregivers. There is a strong need to adapt asthma treatment to the individual patient taking into account underlying inflammatory profiles, moving from a 'one size fits all' approach toward a much-needed personalized approach.

AREAS COVERED

This review article aims to provide an overview of recent advances in the management and treatment of pediatric asthma, including novel insights on the molecular heterogeneity of childhood asthma, the emergence of biologicals to treat severe asthma, and innovative e-health and home monitoring techniques to make asthma management more convenient and accessible.

EXPERT OPINION

Molecular technologies have provided new treatment leads. E-health and home monitoring technologies have helped to gain more insights into disease dynamics and improve adherence to treatment while bringing health care to the patient. However, uncontrolled childhood asthma is still a major unmet clinical need and precision-medicine approaches are still scarce in clinical practice. Advanced omics methods may help researchers or clinicians to more accurately phenotype and treat subtypes of childhood asthma and gain more insight into the complexity of the disease.

Nontypeable Haemophilus influenzae infection of pulmonary macrophages drives neutrophilic inflammation in severe asthma

BACKGROUND

Nontypeable Haemophilus influenzae (NTHi) is a respiratory tract pathobiont that chronically colonizes the airways of asthma patients and is associated with severe, neutrophilic disease phenotypes. The mechanism of NTHi airway persistence is not well understood, but accumulating evidence suggests NTHi can persist within host airway immune cells such as macrophages. We hypothesized that NTHi infection of pulmonary macrophages drives neutrophilic inflammation in severe asthma.

METHODS

Bronchoalveolar lavage (BAL) samples from 25 severe asthma patients were assessed by fluorescence in situ hybridisation to quantify NTHi presence. Weighted gene correlation network analysis (WGCNA) was performed on RNASeq data from NTHi-infected monocyte-derived macrophages to identify transcriptomic networks associated with NTHi infection.

RESULTS

NTHi was detected in 56% of BAL samples (NTHi+) and was associated with longer asthma duration (34 vs 22.5 years, p = .0436) and higher sputum neutrophil proportion (67% vs 25%, p = .0462). WGCNA identified a transcriptomic network of immune-related macrophage genes significantly associated with NTHi infection, including upregulation of T17 inflammatory mediators and neutrophil chemoattractants IL1B, IL8, IL23 and CCL20 (all p < .05). Macrophage network genes SGPP2 (p = .0221), IL1B (p = .0014) and GBP1 (p = .0477) were more highly expressed in NTHi+ BAL and moderately correlated with asthma duration (IL1B; rho = 0.41, p = .041) and lower prebronchodilator FEV1/FVC% (GBP1; rho = -0.43, p = .046 and IL1B; rho = -0.42, p = .055).

CONCLUSIONS

NTHi persistence with pulmonary macrophages may contribute to chronic airway inflammation and T17 responses in severe asthma, which can lead to decreased lung function and reduced steroid responsiveness. Identifying therapeutic strategies to reduce the burden of NTHi in asthma could improve patient outcomes.

Uso de glucocorticoides sistémicos para el tratamiento del asma grave: Consenso multidisciplinar español

Background and aim

Since their effectiveness was initially demonstrated, oral corticosteroids (OCS) have been routinely used to treat asthma. We now know that their usage is linked to the development of side effects such osteoporosis and adrenal insufficiency. This is an observational study based on Delphi methodology. The questionnaire was divided into 4 sections: OCS generalities, maintenance treatment, short-term treatment, and adverse events.

Materials and methods

Two rounds of a 68-item questionnaire were completed by a panel of 48 allergists and pneumologists.

Results

Definitions were agreed upon, as was the proper use of OCS in the treatment of severe asthma. The experts agreed that the use of OCS should be minimized as much as possible and that in the event of maintenance treatments, a slow and progressive tapering strategy should be used. They also emphasized the importance of standardizing the technique for measuring the amount of SCG delivered in both cases.

Conclusions

This consensus document attempts to bring together scientifically supported suggestions from specialists in the management of asthma to reduce the use of OCS in Spain.

Dokumentation von Biologika-Therapien bei chronischer Rhinosinusitis mit Polyposis nasi (CRSwNP): Dupilumab, Omalizumab und Mepolizumab

Hintergrund: Die chronische Rhinosinusitis mit Nasenpolypen (CRSwNP) ist eine multifaktorielle entzündliche Erkrankung der paranasalen Schleimhäute, der als Endotyp meistens eine Typ-2-Inflammation zugrunde liegt. Mittlerweile sind drei Antikörper (Dupilumab, Omalizumab und Mepolizumab) für die Therapie der schweren CRSwNP zugelassen. Eine Dokumentation der Erkrankungsschwere im Behandlungsverlauf ist unverzichtbar.

Methoden: In einer Literaturrecherche in Medline, Pubmed sowie den nationalen und internationalen Studien- und Leitlinienregistern und der Cochrane Library wurde die Immunologie der CRSwNP analysiert und die Evidenz zur Wirkung von Dupilumab, Omalizumab und Mepolizumab bei dieser Erkrankung ermittelt. Hieraus wurden drei Positionspapiere durch unsere Autorengruppe erstellt, die Grundlage dieser zusammenfassenden Übersichtsarbeit sind.

Ergebnisse: Basierend auf den Angaben aus der internationalen Literatur werden von einem Expertengremium Empfehlungen für die Anwendung von Dupilumab, Omalizumab und Mepolizumab bei CRSwNP im deutschen Gesundheitssystem gegeben.

Schlussfolgerung: Dupilumab, Omalizumab und Mepolizumab sind zugelassen für Patienten ab 18 Jahren mit schwerer CRSwNP als Zusatztherapie zu intranasalen Glukokortikosteroiden (INCS), wenn, bei Dupilumab und Mepolizumab, durch eine Therapie mit systemischen Glukokortikosteroiden und/oder chirurgischem Eingriff keine ausreichende Krankheitskontrolle erzielt werden kann. Eine Therapie mit Omalizumab ist angezeigt, wenn eine Therapie mit INCS keine suffiziente Kontrolle der Erkrankung ergibt. Es werden dezidierte Empfehlungen zur Dokumentation der Anwendung im Deutschen Gesundheitssystem gegeben, die auf den hierzu bereits publizierten Positionspapieren unserer Autorengruppe basieren.

Zitierweise: Klimek L, Förster-Ruhrmann U, Beule AG, Chaker AM, Hagemann J, Klimek F, Casper I, Huppertz T, Hoffmann TK, Dazert S, Deitmer T, Olze H, Strieth S, Wrede H, Schlenter W, Welkoborsky H-J, Wollenberg B, Bergmann C, Cuevas M, Beutner C, Gröger M, Becker S. Indicating biologics for chronic rhinosinusitis with nasal polyps (CRSwNP): Recommendations by German Allergy and ORL-societies AeDA and DGHNO for Dupilumab, Omalizumab and Mepolizumab. Allergo J Int 2022;31:149-60

https://doi.org/10.1007/s40629-022-00220-x

Relationship of Peripheral Blood Counts with Asthma Control

OBJECTIVE

To determine the association between blood eosinophil and neutrophil counts with asthma control.

METHODS

This retrospective study, conducted in tertiary care hospital of western India, evaluated the hospital electronic medical record (HEMR) of children aged 5 to 18 y who were diagnosed with asthma as per the Global Initiative for Asthma (GINA) guidelines in the pediatric chest clinic (PCC). Eosinophil and neutrophil counts were recorded from HEMR and asthma control was determined as per the GINA guidelines on follow-up.

RESULTS

A total of 742 children attended the PCC in the last 2 y from March 2017 to February 2019; out of which, blood eosinophil and neutrophil counts were done in 116 children with asthma. The median eosinophil and neutrophil count were 0.46 (0.13, 0.78) × 10⁹/L and 5.08 (3.50, 7.53) × 10⁹/L cells, respectively. Eosinophil count was significantly higher in children with well-controlled asthma as compared to partly/uncontrolled asthma [median eosinophil count 0.46 (0.13, 0.78) vs. 0.40 (0.1, 0.66) × 10⁹/L; p = 0.04]; while the neutrophil count was significantly higher in children with partly/uncontrolled asthma as compared to well-controlled asthma [median neutrophil 6.54 (4.32, 7.92) vs. 4.85 (2.96, 6.86) × 10⁹/L; p = 0.04].

CONCLUSIONS

High lung function is associated with good asthma control. Although not independently associated, the high absolute eosinophil counts (AEC) is associated with better asthma control, while high absolute neutrophil counts (ANC) is associated with poor asthma control.

The Dynamic Contribution of Neutrophils in the Chronic Respiratory Diseases

Asthma, chronic obstructive pulmonary disease, and idiopathic pulmonary fibrosis are representative chronic respiratory diseases (CRDs). Although they differ in terms of disease presentation, they are all thought to arise from unresolved inflammation. Neutrophils are not only the first responders to acute inflammation, but they also help resolve the inflammation. Notably, emerging clinical studies show that CRDs are associated with systemic and local elevation of neutrophils. Moreover, murine studies suggest that airway-infiltrating neutrophils not only help initiate airway inflammation but also prolong the inflammation. Given this background, this review describes neutrophil-mediated immune responses in CRDs and summarizes the completed, ongoing, and potential clinical trials that test the therapeutic value of targeting neutrophils in CRDs. The review also clarifies the importance of understanding how neutrophils interact with other immune cells and how these interactions contribute to chronic inflammation in specific CRDs. This information may help identify future therapeutic strategies for CRDs.

Revisiting differences between atopic and non-atopic asthmatics: When age is shaping airway inflammatory profile

Background

Atopic asthma is one of the most common asthma phenotypes and is generally opposed to the non-atopic counterpart. There have been very few large-scale studies comparing atopic and non-atopic asthmatics in terms of systemic and airway inflammation across the age spectrum.

Methods

Here, we have undertaken a retrospective study investigating 1626 patients (924 atopic and 702 non-atopic asthmatics) recruited from our university asthma clinic who underwent extensive clinical investigations including induced sputum. Atopy was defined by any positive specific IgE to common aeroallergens (>0,35 kU/L). We performed direct comparisons between the groups and sought to appreciate the influence of age on the airway and systemic inflammatory components. The study was approved by the ethics committee of the University Hospital of Liege (Ref. 2016/276). Informed consents were obtained from healthy subjects.

Results

Atopic asthmatics were younger (P < .001), had a higher male/female ratio (P < .001), an earlier disease onset (P < .001) and a greater proportion of treated rhinitis (P < .001) while non-atopic asthmatics had greater smoke exposure (P < .001), lower FEV₁/FVC ratio (P = .01) and diffusing capacity (P < .001). There was no difference between the 2 groups regarding FEV₁ (% predicted), asthma control, asthma quality of life and exacerbations in the previous 12 months. Regarding inflammation, atopic patients had higher FeNO levels (median = 28 ppb, P < .001), were more eosinophilic both in blood (median = 2.8%, P < .001) and in sputum (median = 2.2%, P < .001) while non-atopic patients displayed greater blood (median = 57%, P = .01) and sputum (median = 58.8%, P = .01) neutrophilic inflammation. However, stratifying patients by age showed that non-atopic asthmatics above 50 years old became equally eosinophilic in the sputum (P = .07), but not in the blood, as compared to atopic patients. Likewise, FeNO rose in non-atopic patients after 50 years old but remained, however, lower than in atopic patients.

Conclusions

We conclude that, while sharing many features, atopic group still differentiates from non-atopic asthmatics by demographics, functional and inflammatory profiles. When atopic asthmatics showed a constant eosinophilic pattern across the age spectrum, non-atopic asthmatics were found to be neutrophilic before the age of 50 but eosinophilic above 50 years old.

Stressed out - The role of oxidative stress in airway smooth muscle dysfunction in asthma and COPD

The airway smooth muscle (ASM) surrounding the airways is dysfunctional in both asthma and chronic obstructive pulmonary disease (COPD), exhibiting; increased contraction, increased mass, increased inflammatory mediator release and decreased corticosteroid responsiveness. Due to this dysfunction, ASM is a key contributor to symptoms in patients that remain symptomatic despite optimal provision of currently available treatments. There is a significant body of research investigating the effects of oxidative stress/ROS on ASM behaviour, falling into the following categories; cigarette smoke and associated compounds, air pollutants, aero-allergens, asthma and COPD relevant mediators, and the anti-oxidant Nrf2/HO-1 signalling pathway. However, despite a number of recent reviews addressing the role of oxidative stress/ROS in asthma and COPD, the potential contribution of oxidative stress/ROS-related ASM dysfunction to asthma and COPD pathophysiology has not been comprehensively reviewed. We provide a thorough review of studies that have used primary airway, bronchial or tracheal smooth muscle cells to investigate the role of oxidative stress/ROS in ASM dysfunction and consider how they could contribute to the pathophysiology of asthma and COPD. We summarise the current state of play with regards to clinical trials/development of agents targeting oxidative stress and associated limitations, and the adverse effects of oxidative stress on the efficacy of current therapies, with reference to ASM related studies where appropriate. We also identify limitations in the current knowledge of the role of oxidative stress/ROS in ASM dysfunction and identify areas for future research.

T2-low: what do we know?: Past, present, and future of biologic therapies in noneosinophilic asthma

T2-low asthma is an often severe asthma subtype with limited treatment options and biologic therapeutics are lacking. Several monoclonal antibodies (mAbs) targeting non-T2 cytokines were previously reported to be ineffective in asthma. These trials often investigated heterogeneous asthma populations and negative outcomes could be related to unsuitable study cohorts. More tailored approaches in selecting participants based on specific biomarkers have been beneficial in treating severe T2-high asthma. Similarly, mAbs previously deemed ineffective bear the potential to be useful when administered to the correct target population. Here, we review individual clinical trials conducted between 2005 and 2021 and assess the suitability of the selected cohorts, whether study end points were met, and whether outcome measures were appropriate to investigate the effectiveness of the respective drug. We discuss potential target groups within the T2-low asthma population and suggest biomarkers that may predict a treatment response. Furthermore, we assess whether biomarker-guided approaches or subgroup analyses were associated with more positive study outcomes. The mAbs directed against alarmins intervene early in the inflammatory cascade and are the first mAbs found to have efficacy in T2-low asthma. Several randomized controlled trials performed predefined subgroup analyses that included T2-low asthma. Subgroup analyses were associated with positive outcomes and were able to reveal a stronger response in at least 1 subgroup. A better understanding of T2-low subgroups and specific biomarkers is necessary to identify the most responsive target population for a given mAb.

PM2.5 Exposure and Asthma Development: The Key Role of Oxidative Stress

Oxidative stress is defined as the imbalance between reactive oxygen species (ROS) production and the endogenous antioxidant defense system, leading to cellular damage. Asthma is a common chronic inflammatory airway disease. The presence of asthma tends to increase the production of reactive oxygen species (ROS), and the antioxidant system in the lungs is insufficient to mitigate it. Therefore, asthma can lead to an exacerbation of airway hyperresponsiveness and airway inflammation. PM2.5 exposure increases ROS levels. Meanwhile, the accumulation of ROS will further enhance the oxidative stress response, resulting in DNA, protein, lipid, and other cellular and molecular damage, leading to respiratory diseases. An in-depth study on the relationship between oxidative stress and PM2.5-related asthma is helpful to understand the pathogenesis and progression of the disease and provides a new direction for the treatment of the disease. This paper reviews the research progress of oxidative stress in PM2.5-induced asthma as well as highlights the therapeutic potentials of antioxidant approaches in treatment of asthma.

Severe asthma in children: An official statement from Saudi Pediatric Pulmonology Association

In Saudi Arabia, the prevalence of pediatric asthma ranges between 8% and 25%. However, there are no sufficient data regarding severe asthma in childhood in Saudi Arabia. Therefore, a task force has been formed by the Saudi Pediatric Pulmonology Association which is a subsidiary group of the Saudi Thoracic Society and consists of Saudi experts with well-respected academic and clinical backgrounds in the fields of pediatric asthma as well as other respiratory diseases to write a consensus on definitions, phenotypes, and pathophysiology, evaluation, and management. To achieve this, the subject was divided into various sections, each of which was assigned to at least 2 experts. Without a central literature review, the authors searched the literature using their own strategies. To reach an agreement, the entire panel reviewed and voted on proposed findings and recommendations.

An altered sputum macrophage transcriptome contributes to the neutrophilic asthma endotype

Background

Neutrophilic asthma (NA) is a clinically important asthma phenotype, the cellular and molecular basis of which is not completely understood. Airway macrophages are long‐lived immune cells that exert important homeostatic and inflammatory functions which are dysregulated in asthma. Unique transcriptomic programmes reflect varied macrophage phenotypes in vitro. We aimed to determine whether airway macrophages are transcriptomically altered in NA.

Methods

We performed RNASeq analysis on flow cytometry‐isolated sputum macrophages comparing NA (n = 7) and non‐neutrophilic asthma (NNA, n = 13). qPCR validation of RNASeq results was performed (NA n = 13, NNA n = 23). Pathway analysis (PANTHER, STRING) of differentially expressed genes (DEGs) was performed. Gene set variation analysis (GSVA) was used to test for enrichment of NA macrophage transcriptomic signatures in whole sputum microarray (cohort 1 ‐ controls n = 16, NA n = 29, NNA n = 37; cohort 2 U‐BIOPRED ‐ controls n = 16, NA n = 47, NNA n = 57).

Results

Flow cytometry‐sorting significantly enriched sputum macrophages (99.4% post‐sort, 44.9% pre‐sort, p < .05). RNASeq analysis confirmed macrophage purity and identified DEGs in NA macrophages. Selected DEGs (SLAMF7, DYSF, GPR183, CSF3, PI3, CCR7, all p < .05 NA vs. NNA) were confirmed by qPCR. Pathway analysis of NA macrophage DEGs was consistent with responses to bacteria, contribution to neutrophil recruitment and increased expression of phagocytosis and efferocytosis factors. GSVA demonstrated neutrophilic macrophage gene signatures were significantly enriched in whole sputum microarray in NA vs. NNA and controls in both cohorts.

Conclusions

We demonstrate a pathophysiologically relevant sputum macrophage transcriptomic programme in NA. The finding that there is transcriptional activation of inflammatory programmes in cell types other than neutrophils supports the concept of NA as a specific endotype.

Integrated OMICs Approach for the Group 1 Protease Mite-Allergen of House Dust Mite Dermatophagoides microceras

House dust mites (HDMs) are one of the most important allergy-causing agents of asthma. In central Taiwan, the prevalence of sensitization to Dermatophagoides microceras (Der m), a particular mite species of HDMs, is approximately 80% and is related to the IgE crossing reactivity of Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f). Integrated OMICs examination was used to identify and characterize the specific group 1 mite-allergic component (Der m 1). De novo draft genomic assembly and comparative genome analysis predicted that the full-length Der m 1 allergen gene is 321 amino acids in silico. Proteomics verified this result, and its recombinant protein production implicated the cysteine protease and α chain of fibrinogen proteolytic activity. In the sensitized mice, pathophysiological features and increased neutrophils accumulation were evident in the lung tissues and BALF with the combination of Der m 1 and 2 inhalation, respectively. Principal component analysis (PCA) of mice cytokines revealed that the cytokine profiles of the allergen-sensitized mice model with combined Der m 1 and 2 were similar to those with Der m 2 alone but differed from those with Der m 1 alone. Regarding the possible sensitizing roles of Der m 1 in the cells, the fibrinogen cleavage products (FCPs) derived from combined Der m 1 and Der m 2 induced the expression of pro-inflammatory cytokines IL-6 and IL-8 in human bronchial epithelium cells. Der m 1 biologically functions as a cysteine protease and contributes to the α chain of fibrinogen digestion in vitro. The combination of Der m 1 and 2 could induce similar cytokines expression patterns to Der m 2 in mice, and the FCPs derived from Der m 1 has a synergistic effect with Der m 2 to induce the expression of pro-inflammatory cytokines in human bronchial epithelium cells.

Azithromycin inhibits mucin secretion, mucous metaplasia, airway inflammation and airways hyperresponsiveness in mice exposed to house dust mite extract

Excessive production, secretion and retention of abnormal mucus is a pathologic feature of many obstructive airways diseases including asthma, chronic obstructive pulmonary disease, cystic fibrosis and bronchiectasis. Azithromycin is an antibiotic that also possesses immunomodulatory and mucoregulatory activities, which may contribute to the clinical effectiveness of azithromycin in these obstructive airway diseases. The current study investigated these non-antibiotic activities of azithromycin (or saline) in mice exposed daily to intranasal house dust mite (HDM) extract (or SHAM inoculation) for 10 days. HDM-exposed mice exhibited airways hyperresponsiveness to aerosolised methacholine, a pronounced mixed eosinophilic and neutrophilic inflammatory response, increased airway smooth muscle (ASM) thickness and elevated levels of epithelial mucin staining (compared to SHAM mice). Azithromycin (50 mg/kg s.c., 2 h prior to each HDM exposure) significantly attenuated HDM-induced airways hyperresponsiveness to methacholine, airways inflammation (bronchoalveolar lavage eosinophil and neutrophils numbers, and cytokine/chemokine levels), and epithelial mucin staining (mucous metaplasia) (P<0.05, 2-way ANOVA). Isolated tracheal segments of HDM-exposed mice secreted Muc5ac and Muc5b (above baseline levels) in response to exogenous ATP. Moreover, ATP-induced secretion of mucins was significantly attenuated in segments obtained from azithromycin-treated, HDM-exposed mice (P<0.05, 2-way ANOVA). In additional ex vivo studies, ATP-induced secretion of Muc5ac from HDM-exposed tracheal segments was inhibited by in vitro exposure to azithromycin. In vitro azithromycin also inhibited ATP-induced secretion of Muc5ac and Muc5b in tracheal segments from IL-13-exposed mice. In summary, azithromycin inhibited ATP-induced mucin secretion and airways inflammation in HDM-exposed mice, both of which are likely to contribute to suppression of airways hyperresponsiveness.

Positionspapier: Empfehlungen zur Anwendung von Mepolizumab bei chronischer Rhinosinusitis mit Polyposis nasi (CRSwNP) im deutschen Gesundheitssystem – Empfehlungen des Ärzteverbandes Deutscher Allergologen (AeDA) und der AGs Klinische Immunologie, Allergologie und Umweltmedizin und Rhinologie und Rhinochirurgie der Deutschen Gesellschaft für HNO-Heilkunde, Kopf- und Hals-Chirurgie (DGHNO-KHC)

BACKGROUND

 Chronic rhinosinusitis with nasal polyps (CRSwNP) is a multifactorial inflammatory disease of the paranasal sinus mucosa with eosinophilic inflammation as the most common endotype. The anti-IL5 antibody mepolizumab was approved for the treatment of severe CRSwNP in the EU in November 2021.

METHODS

 A literature search was performed to analyze the immunology of CRSwNP and determine the available evidence by searching Medline, Pubmed, and the German national and international trial and guideline registries and the Cochrane Library. Human studies published in the period up to and including 12/2021 that investigated the effect of mepolizumab in CRSwNP were considered.

RESULTS

 Based on the international literature and previous experience, recommendations for the use of mepolizumab in CRSwNP in the German health care system are given by an expert panel on the basis of a documentation form.

CONCLUSIONS

 Understanding about the immunological basis of CRSwNP opens new non-surgical therapeutic approaches with biologics for patients with severe courses. Mepolizumab is approved since November 2021 for add-on therapy with intranasal corticosteroids for the treatment of adult patients with severe CRSwNP who cannot be adequately controlled with systemic corticosteroids and/or surgical intervention.