Randomized, double-blind, placebo-controlled study of brodalumab, a human anti-IL-17 receptor monoclonal antibody, in moderate to severe asthma

Decoding innate lymphoid cells and innate-like lymphocytes in asthma: pathways to mechanisms and therapies

Asthma is a chronic inflammatory lung disease driven by a complex interplay between innate and adaptive immune components. Among these, innate lymphoid cells (ILCs) and innate-like lymphocytes have emerged as crucial players in shaping the disease phenotype. Within the ILC family, group 2 ILCs (ILC2s), in particular, contribute significantly to type 2 inflammation through their rapid production of cytokines such as IL-5 and IL-13, promoting airway eosinophilia and airway hyperreactivity. On the other hand, innate-like lymphocytes such as invariant natural killer T (iNKT) cells can play either pathogenic or protective roles in asthma, depending on the stimuli and lung microenvironment. Regulatory mechanisms, including cytokine signaling, metabolic and dietary cues, and interactions with other immune cells, play critical roles in modulating their functions. In this review, we highlight current findings on the role of ILCs and innate-like lymphocytes in asthma development and pathogenesis. We also examine the underlying mechanisms regulating their function and their interplay with other immune cells. Finally, we explore current therapies targeting these cells and their effector cytokines for asthma management.

Rhinovirus as a driver of airway T cell dynamics in children with treatment-refractory recurrent wheeze

Severe asthma in children is notoriously difficult to treat, and its immunopathogenesis is complex. In particular, the contribution of T cells and relationships to antiviral immunity remain enigmatic. Here, we coupled deep phenotyping with machine learning methods to elucidate the dynamics of T cells in the lower airways of children with treatment-refractory recurrent wheeze, and examine rhinovirus (RV) as a driver. Our strategy revealed a T cell landscape dominated by type 1 and type 17 CD8+ signatures. Interrogation of phenotypic relationships coupled with trajectory mapping identified T cell migratory and differentiation pathways spanning the blood and airways that culminated in tissue residency, and involved transitions between type 1 and type 17 tissue-resident types. These dynamics were reflected in cytokine polyfunctionality. Use of machine learning tools to cross-compare T cell populations that were enriched in the airways of RV-positive children with those induced in the blood following experimental RV challenge precisely pinpointed RV-responsive signatures that contributed to T cell migratory and differentiation pathways. Despite their rarity, these signatures were also detected in the airways of RV-negative children. Together, our results underscore the aberrant nature of type 1 immunity in the airways of children with recurrent wheeze, and implicate an important viral trigger as a driver.

Mucins and Their Roles in Asthma

Mucus is a crucial component of airway host defense. For optimal protection, its chief components-the mucins MUC5AC and MUC5B-need to be tightly regulated. Their expression localizes to specific secretory epithelial cell types capable of producing and secreting massive glycopolymers. In asthma, abnormal mucus is an important clinical problem that is effectively treated with therapies that directly target mucins. This review summarizes what is known about how mucin gene regulation, protein synthesis, and secretion are regulated in healthy and asthmatic lungs. Ultimately, a better understanding of these processes could help identify novel ways of preventing or reversing airway mucus dysfunction.

Obesity: Next game changer of allergic airway diseases?

Obesity and allergic diseases are global health concerns, both of which are seeing an increase in prevalence in recent years. Obesity has been recognised as an important comorbidity in subpopulations with allergic airway diseases, which represents a unique phenotype and endotype. Obesity-related allergic airway diseases are associated with exacerbated clinical symptom burden, altered immune response, increased disease severity and compromised predictive capability of conventional biomarkers for evaluating endotype and prognosis. Moreover, treatment of obesity-related allergic airway diseases is challenging because this unique endotype and phenotype is associated with poor response to standard therapeutic strategies. Therapeutic regimen that involves weight loss by non-surgical and surgical interventions, gut microbiome-targeted treatment, glucagon-like peptide-1 receptor agonist and other agents should be considered in this population. In this review, we outline the current knowledge of the impact of obesity on prevalence, endotypes, clinical symptom and management of allergic airway diseases. Increased understanding of the implications of obesity may contribute to better treatment options for the obesity-related refractory airway inflammation, particularly in precision medicine. KEY POINTS: Obesity can increase the prevalence of allergic airway diseases such as asthma, AR, and CRSwNP. Obesity alters the immune endotype and exacerbates clinical symptoms of respiratory allergic diseases. Obesity-related allergic airway diseases exhibit therapeutic resistance to standard treatment. Obesity-related allergic airway diseases constitute a distinct category of endotypes and phenotypes, requiring further in-depth research and novel therapeutic approaches.

Exploring the pathogenesis and clinical implications of asthma, chronic obstructive pulmonary disease (COPD), and asthma-COPD overlap (ACO): a narrative review

The complexity and diversity of the immune response in patients with asthma, chronic obstructive pulmonary disease (COPD), and asthma-COPD overlap present significant challenges for disease management. Relying on a limited number of biomarkers and clinical data is insufficient to fully reveal the immunopathogenesis of these diseases. However, in vitro technologies such as cell analysis, cytokine investigation, and nucleic acid sequencing have provided new insights into the underlying mechanisms of these diseases, leading to the discovery of several biomarkers-including cell degranulation, cell function, secreted cytokines, and single nucleotide polymorphisms-that have potential clinical implications. This paper reviews the immunopathogenesis in asthma, chronic obstructive pulmonary disease, and asthma-COPD overlap and examines the applications of recent in vitro models to detect candidate biomarkers that could enhance diagnostic precision, predict severity, monitor treatments, and develop new treatment strategies. A deeper understanding of the immune response in these diseases, along with the integration of in vitro models into clinical practice, could greatly improve the management of these respiratory diseases, making approaches more personalized and efficient.

Severe asthma beyond bronchodilators: Emerging therapeutic approaches

Asthma is characterized by reversible airway inflammation, obstruction, and structural remodeling, which lead to the eosinophils and lymphocytes accumulation at inflammation sites and the release of inflammatory cells, like mast cells and dendritic cells, from lungs' epithelial and smooth muscle cells that trigger the activation and release of cytokines and chemokines, attracting more cells and contributing to asthma development. Available pharmacological interventions, like bronchodilators and anti-inflammatory agents, are considered generally safe and effective to treat asthma, but many affected individuals with severe asthma still struggle with symptom control. This review highlights recent innovative therapies, such as chemoattractant receptor-homologous molecule expressed on Th2 cell (CRTH2) antagonists, S-nitrosoglutathione reductase (GSNOR) and phosphodiesterase (PDE) inhibitors, and other novel biological agents, which offer potential new strategies for managing severe asthma and may alter the disease's course. Kew words. Inflammation; CRTH2; GSNOR; PDE; Interleukins; Biological agents.

The immunology of asthma and chronic rhinosinusitis

Asthma and chronic rhinosinusitis (CRS) are common chronic inflammatory diseases of the respiratory tract that have increased in prevalence over the past five decades. The clinical relationship between asthma and CRS has been well recognized, suggesting a common pathogenesis between these diseases. Both diseases are driven by complex airway epithelial cell and immune cell interactions that occur in response to environmental triggers such as allergens, microorganisms and irritants. Advances, including a growing understanding of the biology of the cells involved in the disease, the application of multiomics technologies and the performance of large-scale clinical studies, have led to a better understanding of the pathophysiology and heterogeneity of asthma and CRS. This research has promoted the concept that these diseases consist of several endotypes, in which airway epithelial cells, innate lymphoid cells, T cells, B cells, granulocytes and their mediators are distinctly involved in the immunopathology. Identification of the disease heterogeneity and immunological markers has also greatly improved the protocols for biologic therapies and the clinical outcomes in certain subsets of patients. However, many clinical and research questions remain. In this Review, we discuss recent advances in characterizing the immunological mechanisms of asthma and CRS, with a focus on the main cell types and molecules involved in these diseases.

Airway epithelial cells as drivers of severe asthma pathogenesis

Our understanding of the airway epithelium's role in driving asthma pathogenesis has evolved over time. From being regarded primarily as a physical barrier that could be damaged via inflammation, the epithelium is now known to actively contribute to asthma development through interactions with the immune system. The airway epithelium contains multiple cell types with specialized functions spanning barrier action, mucociliary clearance, immune cell recruitment, and maintenance of tissue homeostasis. Environmental insults may cause direct or indirect injury to the epithelium leading to impaired barrier function, epithelial remodelling, and increased release of inflammatory mediators. In severe asthma, the epithelial barrier repair process is inhibited and the response to insults is exaggerated, driving downstream inflammation. Genetic and epigenetic mechanisms also maintain dysregulation of the epithelial barrier, adding to disease chronicity. Here, we review the role of the airway epithelium in severe asthma and how targeting the epithelium can contribute to asthma treatment.

Asthma Phenotypes and Biomarkers

Asthma experienced by both adults and children is a phenotypically heterogeneous condition. Severe asthma, characterized by ongoing symptoms and airway inflammation despite high doses of inhaled and/or systemic corticosteroids, is the focus of research efforts to understand this underlying heterogeneity. Clinical phenotypes in both adult and pediatric asthma have been determined using supervised definition-driven classification and unsupervised data-driven clustering methods. Efforts to understand the underlying inflammatory patterns of severe asthma have led to the seminal discovery of type 2-high versus type 2-low phenotypes and to the development of biologics targeted at type 2-high inflammation to reduce the rates of severe asthma exacerbations. Type 2-high asthma is characterized by upregulation of T helper 2 immune pathways including interleukin (IL)-4, IL-5, and IL-13 along with eosinophilic airway inflammation, sometimes allergic sensitization, and responsiveness to treatment with corticosteroids. Type 2-low asthma is poorly responsive to corticosteroids and is not as well characterized as type 2-high asthma. Type 2-low asthma is limited by being defined as the absence of type 2-high inflammatory markers. Choosing a biologic for the treatment of severe asthma involves the evaluation of a panel of biomarkers such as blood eosinophils, total and specific immunoglobulin E/allergic sensitization, and fractional exhaled nitric oxide. In this review, we focus on the underlying pathobiology of adult and pediatric asthma, discuss the different phenotype-based treatment options for adult and pediatric type 2-high with or without allergic asthma and type 2-low asthma, and describe a clinical phenotyping approach to patients to guide out-patient therapy. Finally, we end with a discussion of whether pediatric asthma exacerbations necessitating admission to an ICU constitute their own high-risk phenotype and/or whether it is a part of other previously defined high-risk subgroups such as difficult-to-control asthma, exacerbation-prone asthma, and severe treatment-resistant asthma.

Emerging biological treatments for asthma

INTRODUCTION

Severe asthma is a chronic airway disease characterized by many pathomechanisms known as endotypes. Biological therapies targeting severe asthma endotypes have significantly improved the treatment of this disease, thus remarkably bettering patient quality of life.

AREAS COVERED

This review aims to describe current biological therapies for severe asthma, highlighting emerging ones. Several studies have confirmed the beneficial effects of currently available monoclonal antibodies targeting immunoglobulin E (IgE), interleukin-5 (IL-5) or its receptor, and interleukin-4 (IL-4)/interleukin-13 (IL-13) receptors (IL-4R/IL-13R). However, patients with T2-low asthma are not eligible for the above biological therapies.

EXPERT OPINION

New treatments are now moving toward targeting the upstream pathways of asthma pathogenesis, coordinated by innate cytokines such as alarmins. These key proinflammatory mediators orchestrate the activation of complex cellular networks including both innate and adaptive immune responses. Alarmins include thymic stromal lymphopoietin (TSLP), interleukin-25 (IL-25), and interleukin-33 (IL-33), which are released from injured airway epithelial cells. TSLP and the other alarmins are suitable targets of biological therapies which are effective for add-on treatment of type 2 asthma. Moreover, anti-alarmin monoclonal antibodies can be also beneficial for patients with T2-low, poorly controlled severe asthma.

Transcriptomic Profiles in Nasal Epithelium and Asthma Endotypes in Youth

Importance

T helper 2 (T2) cells and T helper 17 (T17) cells are CD4+ T cell subtypes involved in asthma. Characterizing asthma endotypes based on these cell types in diverse groups is important for developing effective therapies for youths with asthma.

Objective

To identify asthma endotypes in school-aged youths aged 6 to 20 years by examining the distribution and characteristics of transcriptomic profiles in nasal epithelium.

Design, Setting, and Participants

Cross-sectional analysis of nasal epithelial samples from 3 studies of youths with asthma aged 6 to 20 years: Stress and Treatment Response in Puerto Rican and African American Children with Asthma (STAR; N = 156), Epigenetic Variation and Childhood Asthma in Puerto Ricans (EVA-PR; N = 237), and Vitamin D Kids Asthma (VDKA; N = 66).

Main Outcomes and Measures

The primary outcome was nasal epithelial transcription profiles of 3 T2 and 5 T17 pathway genes. Clinical characteristics, total and allergen-specific immunoglobulin E (IgE), blood eosinophils, and lung function were compared across profiles in all studies.

Results

Mean ages for STAR, EVA-PR, and VDKA participants were 14.2, 15.4, and 10.3 years, respectively. The percentage of female participants ranged from 41% to 53.2% across studies. The predominant race or ethnicity was Puerto Rican in EVA-PR (100%) and Black or African American in STAR (71.8%) and VDKA (57.6%). Three transcriptomic profiles were identified: high T2 expression (T2HIGH), high T17 expression (T17HIGH), and low expression of both pathways (T2LOW/T17LOW). Across studies, T2HIGH was present in 23% to 29% of participants, T17HIGH in 35% to 47%, and T2LOW/T17LOW in 30% to 38%. In each study, median total IgE and blood eosinophils for the T2HIGH profile was higher than for the T2LOW profiles (IgE, 584-869 vs 105-382 IU/mL; eosinophils, 343-560 vs 164-413 cells/mL). Of the participants in all profiles, at least 50% had 1 or more positive allergen-specific IgEs. A differential expression meta-analysis identified 3516 and 2494 differentially expressed genes for the T2HIGH and T17HIGH profiles, respectively. The T17HIGH profile was associated with interleukin 17 and neutrophil signaling pathways and the T2HIGH profile was associated with interleukin 13 signaling pathways.

Conclusions and Relevance

Nasal transcriptomic profiles consistent with T2-high, T17-high, and T2-low/T17-low endotypes occurred in similar proportions across 3 studies of predominantly racially and ethnically minoritized youths with asthma. Most participants had T2-low asthma endotypes and sensitization to 1 or more allergens was common among these endotypes.

A population of c-kit+ IL-17A+ ILC2s in sputum from individuals with severe asthma supports ILC2 to ILC3 trans-differentiation

In prednisone-dependent severe asthma, uncontrolled sputum eosinophilia is associated with increased numbers of group 2 innate lymphoid cells (ILC2s). These cells represent a relatively steroid-insensitive source of interleukin-5 (IL-5) and IL-13 and are considered critical drivers of asthma pathology. The abundance of ILC subgroups in severe asthma with neutrophilic or mixed granulocytic (both eosinophilic and neutrophilic) airway inflammation, prone to recurrent infective exacerbations, remains unclear. Here, we found by flow cytometry that sputum ILC3s are increased in severe asthma with intense airway neutrophilia, whereas equivalently raised sputum ILC2s and ILC3s were found in severe asthma with mixed granulocytic inflammation. Unbiased clustering analyses identified an "intermediate-ILC2" population displaying markers of both ILC2s (prostaglandin D2 receptor 2; CRTH2, IL-5, and IL-13) and ILC3s (c-kit and IL-17A) that were most abundant in severe asthma with mixed granulocytic airway inflammation. Intermediate ILC2s correlated with airway neutrophilia and were associated with increased amounts of IL-1β and IL-18 in sputum supernatants. Coculture of sort-purified canonical ILC2s with IL-1β and IL-18 in vitro up-regulated c-kit and IL-17A as well as gene expression profiles related to both type 2 and type 17 inflammatory pathways. Together, we have identified an intermediate-ILC2 phenotype in the airways of individuals with severe mixed granulocytic asthma, representing a candidate therapeutic target for controlling neutrophilic airway inflammation.

Asthma Biologics Across the T2 Spectrum of Inflammation in Severe Asthma: Biomarkers and Mechanism of Action

Airway inflammation, a hallmark feature of asthma, drives many canonical features of the disease, including airflow limitation, mucus plugging, airway remodeling, and hyperresponsiveness. The T2 inflammatory paradigm is firmly established as the dominant mechanism of asthma pathogenesis, largely due to the success of inhaled corticosteroids and biologic therapies targeting components of the T2 pathway, including IL-4, IL-5, IL-13, and thymic stromal lymphopoietin (TSLP). However, up to 30% of patients may lack signatures of meaningful T2 inflammation (ie, T2 low). In T2-low asthma patients, T2 inflammation may be masked due to anti-inflammatory treatments or may be highly variable depending on exposure to common asthma triggers such as allergens, respiratory infections, and smoke or pollution. The epithelium and epithelial cytokines (TSLP, IL-33) are increasingly recognized as upstream drivers of canonical T2 pathways and as modulators of various effector cells, including mast cells, eosinophils, and neutrophils, which impact the pathological manifestations of airway smooth muscle hypertrophy, hypercontractility, and airway hyperresponsiveness. Approved biologics for severe asthma target several distinct mechanisms of action, leading to differential effects on the spectrum of T2 inflammation, inflammatory biomarkers, and treatment efficacy (reducing asthma exacerbations, improving lung function, and diminishing symptoms). The approved anti-asthma biologics primarily target T2 immune pathways, with little evidence suggesting a benefit of targeting non-T2 asthma-associated mediators. Indeed, many negative results challenge current assumptions about the etiology of non-T2 asthma and raise doubts about the viability of targeting popular alternative inflammatory pathways, such as T17. Novel data have emerged from the use of biologics to treat various inflammatory mediators and have furthered our understanding of pathogenic mechanisms that drive asthma. This review discusses inflammatory pathways that contribute to asthma, quantitatively outlines effects of available biologics on biomarkers, and summarizes data and challenges from clinical trials that address non-T2 mechanisms of asthma.

Novel asthma treatments: Advancing beyond approved novel step-up therapies for asthma

Over the past 2 decades, the management of severe asthma has shifted from relying on inhaled corticosteroids and bronchodilators to more precise, targeted approaches. Monoclonal antibodies designed to address specific molecular pathways in asthma have transformed care for patients with severe asthma. Because therapy targeting IgE became the first biologic developed for allergic asthma in 2003, monoclonal antibodies targeting interleukin (IL)-5, IL-5 receptor, IL-4/-13 receptor, and thymic stromal lymphopoietin have been approved for treating difficult-to-treat asthma, improving symptoms, reducing exacerbations, and reducing oral corticosteroid dosing. Despite these advances, many patients continue to experience asthma exacerbations and symptoms and fail to achieve remission. To address this, pharmaceutical companies and researchers are exploring novel therapies targeting different aspects of asthma pathophysiology, including cytokines, enzymes, and cellular pathways. Innovative treatments such as inhaled biologics, ultra-long-acting biologics, and combination biologics are in development. New molecular targets, such as Bruton tyrosine kinase, OX-40 ligand, and Janus kinase, offer promise for addressing unmet needs in asthma care. Although many therapies have failed to get approval for use because of a lack of efficacy, trial design, or toxicity, these experiments still provide insights into asthma's underlying mechanisms. The future of asthma management looks promising, with emerging therapies aiming to improve patient outcomes. The challenge will lie in identifying the right therapy for each patient and developing personalized treatment strategies.

Molecular mechanisms and clinical impact of biologic therapies in severe asthma

Severe asthma is a critical condition for patients with asthma, characterized by frequent exacerbations, decreased pulmonary function, and unstable symptoms related to asthma. Consequently, the administration of systemic corticosteroids, which cause secondary damage because of their adverse effects, is considered. Recently, several types of molecular-targeted biological therapies have become available for patients with severe asthma, and they have a capacity to improve the pathophysiology of severe asthma. However, several clinical reports indicate that the effects differ depending on the biological targets of asthma in individual patients. In this review, the molecular mechanisms and clinical impact of biologic therapies in severe asthma are described. In addition, molecules targeted by possible future biologics are also addressed. Better understanding of the mechanistic basis for the role of biologics in severe asthma could lead to new therapeutic options for these patients.

Group 3 Innate Lymphoid Cells: A Potential Therapeutic Target for Steroid Resistant Asthma

Asthma is a chronic airway inflammatory disease that affects millions globally. Although glucocorticoids are a mainstay of asthma treatment, a subset of patients show resistance to these therapies, resulting in poor disease control and increased morbidity. The complex mechanisms underlying steroid-resistant asthma (SRA) involve Th1 and Th17 lymphocyte activity, neutrophil recruitment, and NLRP3 inflammasome activation. Recent studies provided evidence that innate lymphoid cells type 3 (ILC3s) might be potential therapeutic targets for non-eosinophilic asthma (NEA) and SRA. Like Th17 cells, ILC3s play crucial roles in immune responses, inflammation, and tissue homeostasis, contributing to disease severity and corticosteroid resistance in NEA. Biologics targeting ILC3-related pathways have shown promise in managing Th2-low asthma, suggesting new avenues for SRA treatment. This review aims to explore the risk factors for SRA, discuss the challenges and mechanisms underlying SRA, consolidate current findings on innate lymphoid cells, and elucidate their role in respiratory conditions. We present the latest findings on the involvement of ILC3s in human diseases and explore their potential mechanisms in SRA development. Furthermore, we review emerging therapeutic biologics targeting ILC3-related pathways in managing NEA and SRA. This review highlights current challenges, and emerging therapeutic strategies, and addresses a significant gap in asthma research, with implications for improving the management of steroid-resistant asthma.

Low-Dose Oral Ginger Improves Daily Symptom Scores in Asthma

Background/Objective: A significant number of individuals with asthma have poorly controlled daily symptoms and utilize dietary supplements such as ginger in a quest for improved symptom control; however, its effectiveness at improving the control of symptoms is unproven. We questioned whether low-dose oral ginger would improve subjective and objective measurements of asthma control in mild-to-moderate asthmatics. Methods: We performed a randomized, placebo-controlled, double-blinded study of a low dose (1 g twice daily) of a dietary supplement of ginger in 32 mild-to-moderate uncontrolled asthmatics over a 2-month trial period while maintaining daily conventional asthma therapies. The planned primary outcomes included an increased tolerance to inhaled methacholine and decreased concentrations of fractional excretion of exhaled nitric oxide (FeNO). Secondary planned outcomes included measurements of asthma control by the Asthma Control Test (ACT), a 2-week symptom recall test, and the Juniper mini Asthma Quality of Life Questionnaire (AQLQ), and blood eosinophils and asthma-associated cytokines. Results: Exhaled nitric oxide or blood eosinophils were not changed by oral ginger. However, three different measures of asthma symptom control were improved by the 28-day time point of oral ginger. Asthma-associated serum cytokines (IL-13 and IL-17A) were modulated by oral ginger. Conclusions: This is the first demonstration that a small daily dose of a dietary supplement of ginger may improve asthma symptoms and reduce inflammation in human asthmatics. These findings support the need for additional studies using larger doses of ginger in specific endotypes of asthmatics that may identify a novel therapeutic for asthma.

Silencing SMAD4 inhibits inflammation and ferroptosis in asthma by blocking the IL-17A signaling pathway

BACKGROUND

The TGF-β/SMAD signaling pathway is crucial in the pathogenesis of asthma. However, SMAD family member 4 (SMAD4), a key mediator of TGF-β, its roles and underlying mechanisms in asthma remain unclear.

METHODS

The in vivo and in vitro roles of SMAD4 in asthma were investigated through an ovalbumin (OVA)-induced mouse model and an interleukin-13 (IL-13)-induced cell model. The molecular mechanism of SMAD4 influenced asthma was examined using transcriptome sequencing, followed by feedback experiments involving recombinant human interleukin 17 A (rhIL-17 A), an IL-17 A signaling pathway activator.

RESULTS

SMAD4 was highly expressed in the asthma models. SMAD4 silencing alleviated damage to lung tissue and decreased inflammatory infiltration. Expression levels of Caspase-3, IgG, and inflammatory factors were reduced after silencing SMAD4. Silencing SMAD4 suppressed ferroptosis. Silencing SMAD4 also enhanced IL-13-induced BEAS-2B cell proliferation and suppressed apoptosis. Furthermore. IL-17 A signaling pathway was promoted in the asthma models, as evidenced by elevated IL-17RA, IL-17 A, and Act1 protein levels. SMAD4 silencing inhibited the expression levels of these IL-17 A pathway-associated proteins. Moreover, rhIL-17 A treatment notably reversed the impacts of SMAD4 silencing on asthma in the IL-13-induced cell model and OVA-induced mouse model, indicating that silencing SMAD4 inhibited inflammation and ferroptosis in asthma by blocking the IL-17 A signaling pathway.

CONCLUSION

Silencing SMAD4 prevents inflammation and ferroptosis in asthma by inhibiting the IL-17 pathway, which provides a novel potential approach for asthma therapy.

Co-Occurrence of Psoriasis and Asthma in the Pediatric Population: A Systematic Review and Meta-Analysis

Introduction: The risk of asthma in patients with psoriasis and that of psoriasis in patients with asthma have increased, but relevant data for the pediatric population are lacking. Therefore, we performed a meta-analysis to assess the pooled association between psoriasis and asthma in children and adolescents. Methods: We conducted an extensive search of the medical literature databases through to July 2024. The estimated risk ratios (RRs) and corresponding 95% confidence intervals (CIs) were computed. Results: Three studies, involving 5310 children with psoriasis and 1,539,029 control participants, were included to evaluate the incidence of asthma in children with psoriasis. The meta-analysis indicated a significantly increased risk of asthma in children with psoriasis [RR 1.38 (95% CI, 1.28-1.49)]. Additionally, two studies involving 104,369 asthmatic children and 1,539,029 controls were included to evaluate the incidence of psoriasis in children with asthma. The meta-analysis indicated a significant increase in the risk of psoriasis in children with asthma [RR 1.17 (95% CI, 0.70-1.95)]. Conclusions: This meta-analysis offers evidence supporting the association between psoriasis and asthma in pediatric populations. Therefore, physicians should make patients aware of the connection between these two chronic diseases.

Rhinovirus as a Driver of Airway T-Cell Dynamics in Children with Severe Asthma

Severe asthma in children is notoriously difficult to treat, and its immunopathogenesis is complex. In particular, the contribution of T cells and relationships to anti-viral immunity, remain enigmatic. Here, we coupled deep phenotyping with machine learning methods to resolve the dynamics of T cells in the diseased lower airways, and examined rhinovirus (RV) as a driver. Our strategy revealed a T-cell landscape dominated by type 1 and type 17 CD8+ signatures. Interrogation of phenotypic relationships coupled with trajectory mapping identified T-cell migratory and differentiation pathways spanning the blood and airways that culminated in tissue residency, and included transitions between type 1 and type 17 tissue-resident types. These T-cell dynamics were reflected in cytokine polyfunctionality in situ . Use of machine learning to cross-compare T-cell populations that were enriched in the airways of RV-positive children with those induced in the blood after RV challenge in an experimental infection model, precisely pinpointed RV-responsive signatures that mapped to T-cell differentiation pathways. Despite their rarity, these signatures were detected in the airways of uninfected children. Together, our results underscore the aberrant nature of type 1 immunity in the airways of children with severe asthma, and implicate an important viral trigger as a driver.

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.

A new Anticalin protein for IL-23 inhibits non-type 2 allergen-driven mouse lung inflammation and airway hyperresponsiveness

Severe asthma is a syndromic label assigned to patients based on clinical parameters, yet there are diverse underlying molecular endotypes in severe asthma pathobiology. Immunophenotyping of asthma biospecimens commonly includes a mixture of granulocytes and lymphocytes. Recently, a subset of patients with severe asthma was defined as non-type 2 with neutrophil-enriched inflammation associated with increased Th17 CD4+ T cells and IL-17 levels. Here, we used an allergen-driven mouse model of increased IL-17 and mixed granulocyte lung inflammation to determine the impact of upstream regulation by an Anticalin protein that specifically binds IL-23. Airway administration of the IL-23-binding Anticalin protein (AcIL-23) decreased lung neutrophils, eosinophils, macrophages, lymphocytes, IL-17+ CD4 T cells, mucous cell metaplasia, and methacholine-induced airway hyperresponsiveness. Selective targeting of IL-23 with a monoclonal antibody (IL-23p19; αIL-23) also decreased macrophages, IL-17+ CD4 T cells, and airway hyperresponsiveness. In contrast, a monoclonal antibody against IL-17A (αIL-17A) had no significant effect on airway hyperresponsiveness but did decrease lung neutrophils, macrophages, and IL-17+ CD4 T cells. Targeting the IL-23 pathway did not significantly change IL-5+ or IL-13+ CD4 T cells. Together, these data indicate that airway AcIL-23 mirrored the activity of systemic anti-IL-23 antibody to decrease airway hyperresponsiveness in addition to mixed granulocytic inflammation and that these protective actions were broader than blocking IL-17A or IL-5 alone, which selectively decreased airway neutrophils and eosinophils, respectively.NEW & NOTEWORTHY This is the first report of an Anticalin protein engineered to neutralize IL-23 (AcIL-23). Airway administration of AcIL-23 in mice regulated allergen-driven airway inflammation, mucous cell metaplasia, and methacholine-induced airway hyperresponsiveness. In mixed granulocytic allergic lung inflammation, immune regulation of IL-23 was broader than neutralization of either IL-17 or IL-5.

Biologics in Chronic Rhinosinusitis: Current and Emerging

Chronic rhinosinusitis (CRS) is categorized phenotypically into CRS with and without nasal polyps (CRSwNP, CRSsNP). Endotyping categorizes the disease based on immune cell activity and inflammatory mechanisms into Type 1, Type 2, and Type 3. The Type 2 endotype is the most researched and associated with asthma, atopic disease, and severe CRSwNP. For patients with poorly controlled CRSwNP, there are 3 approved biologic treatments: omalizumab, dupilumab, and mepolizumab. Many other biologics are being tested in Type 2, non-Type 2, and mixed endotypes in CRSwNP and CRSsNP. These studies will play a significant role in shaping the future of CRS management.

Biologics in Asthma: Emerging Biologics

Advances in our understanding of asthma pathophysiology have led to the advent of multiple targeted asthma therapies such as biologics. However, partial response to biologics occurs, indicating residual disease activity in some patients. Hence, there exists a need for new therapies that focus on novel pathways, alongside perhaps evaluation of combination biologic therapies and modulators of downstream cytokine activation. Therefore, although our current focus is on biologics; it is critical to take a more holistic approach including consideration for nonbiologic therapies that have the potential to significantly advance asthma care.

Allergenic protein-induced type I hypersensitivity models: a review

Context

Type I hypersensitivity affects approximately one-third of the global population. As the pathophysiology underlying the development of type I hypersensitivity (asthma, food allergy, and anaphylactic shock, etc.) is complex and heterogeneous, animal model studies continue to be the key to identifying novel molecular pathways and providing therapeutic strategies.

Objective

Selection of the animal model should be done with careful consideration of the protocol variables, animal species, and strains to accurately reflect the clinical symptoms typical of humans.

Methods

The following databases were searched: PubMed and Web of Science.

Results and conclusion

Foreign allergens include allergenic proteins and chemical haptens. This review summarizes the various methods used for designing animal models of common allergenic protein-induced type I hypersensitivity, namely, passive anaphylaxis model, active systemic anaphylaxis/anaphylaxis shock model, food allergy model, asthma model, and IgE-mediated cell models. Additionally, we summarize shrimp tropomyosin-induced type I hypersensitivity models from our previous studies and discuss their advantages and limitations compared with that of ovalbumin-induced models.

Regulation of Airway Epithelial-Derived Alarmins in Asthma: Perspectives for Therapeutic Targets

Asthma is a chronic respiratory condition predominantly driven by a type 2 immune response. Epithelial-derived alarmins such as thymic stromal lymphopoietin (TSLP), interleukin (IL)-33, and IL-25 orchestrate the activation of downstream Th2 cells and group 2 innate lymphoid cells (ILC2s), along with other immune effector cells. While these alarmins are produced in response to inhaled triggers, such as allergens, respiratory pathogens or particulate matter, disproportionate alarmin production by airway epithelial cells can lead to asthma exacerbations. With alarmins produced upstream of the type 2 inflammatory cascade, understanding the pathways by which these alarmins are regulated and expressed is critical to further explore new therapeutics for the treatment of asthmatic patients. This review emphasizes the critical role of airway epithelium and epithelial-derived alarmins in asthma pathogenesis and highlights the potential of targeting alarmins as a promising therapeutic to improve outcomes for asthma patients.

Immunologic aspects of asthma: from molecular mechanisms to disease pathophysiology and clinical translation

In the present review, we focused on recent translational and clinical discoveries in asthma immunology, facilitating phenotyping and stratified or personalized interventions for patients with this condition. The immune processes behind chronic inflammation in asthma exhibit marked heterogeneity, with diverse phenotypes defining discernible features and endotypes illuminating the underlying molecular mechanisms. In particular, two primary endotypes of asthma have been identified: "type 2-high," characterized by increased eosinophil levels in the airways and sputum of patients, and "type 2-low," distinguished by increased neutrophils or a pauci-granulocytic profile. Our review encompasses significant advances in both innate and adaptive immunities, with emphasis on the key cellular and molecular mediators, and delves into innovative biological and targeted therapies for all the asthma endotypes. Recognizing that the immunopathology of asthma is dynamic and continuous, exhibiting spatial and temporal variabilities, is the central theme of this review. This complexity is underscored through the innumerable interactions involved, rather than being driven by a single predominant factor. Integrated efforts to improve our understanding of the pathophysiological characteristics of asthma indicate a trend toward an approach based on disease biology, encompassing the combined examination of the clinical, cellular, and molecular dimensions of the disease to more accurately correlate clinical traits with specific disease mechanisms.

Update on Inflammatory Biomarkers for Defining Asthma Phenotype

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

Neutrophil and neutrophil extracellular trap involvement in neutrophilic asthma: A review

Asthma is a highly prevalent chronic inflammatory disease characterized by variable airflow obstruction and airway hyperresponsiveness. Neutrophilic asthma (NA) is classified as "type 2 low" asthma, defined as 65% or more neutrophils in the total cell count. There is no clear consensus on the pathogenesis of NA, and the accumulation of neutrophils and release of neutrophil extracellular traps (NETs) may be responsible for its development. A NET is a large extracellular meshwork comprising cell membrane and granule proteins. It is a powerful antimicrobial defence system that traps, neutralizes, and kills bacteria, fungi, viruses, and parasites and prevents the spread of microorganisms. However, dysregulation of NETs may lead to chronic airway inflammation, is associated with worsening of asthma, and has been the subject of major research advances in chronic lung diseases in recent years. NA is insensitive to steroids, and there is a need to find effective biomarkers as targets for the treatment of NA to replace steroids. This review analyses the mechanisms of action between asthmatic neutrophil recruitment and NET formation and their impact on NA development. It also discusses their possible therapeutic significance in NA, summarizing the advances made in NA agents and providing strategies for the treatment of NA, provide a theoretical basis for the development of new therapeutic drugs, thereby improving the level of diagnosis and treatment, and promoting the research progress in the field of asthma.

Asthma Pathogenesis: Phenotypes, Therapies, and Gaps: Summary of the Aspen Lung Conference 2023

Although substantial progress has been made in our understanding of asthma pathogenesis and phenotypes over the nearly 60-year history of the Aspen Lung Conferences on asthma, many ongoing challenges exist in our understanding of the clinical and molecular heterogeneity of the disease and an individual patient's response to therapy. This report summarizes the proceedings of the 2023 Aspen Lung Conference, which was organized to review the clinical and molecular heterogeneity of asthma and to better understand the impact of genetic, environmental, cellular, and molecular influences on disease susceptibility, heterogeneity, and severity. The goals of the conference were to review new information about asthma phenotypes, cellular processes, and cellular signatures underlying disease heterogeneity and treatment response. The report concludes with ongoing gaps in our understanding of asthma pathobiology and provides some recommendations for future research to better understand the clinical and basic mechanisms underlying disease heterogeneity in asthma and to advance the development of new treatments for this growing public health problem.

Molecular Pathways and Potential Therapeutic Targets of Refractory Asthma

Asthma is a chronic inflammatory lung disease. Refractory asthma poses a significant challenge in management due to its resistance to standard therapies. Key molecular pathways of refractory asthma include T2 inflammation mediated by Th2 and ILC2 cells, eosinophils, and cytokines including IL-4, IL-5, and IL-13. Additionally, non-T2 mechanisms involving neutrophils, macrophages, IL-1, IL-6, and IL-17 mediate a corticosteroid resistant phenotype. Mediators including alarmins (IL-25, IL-33, TSLP) and OX40L have overlap between T2 and non-T2 inflammation and may signify unique pathways of asthma inflammation. Therapies that target these pathways and mediators have proven to be effective in reducing exacerbations and improving lung function in subsets of severe asthma patients. However, there are patients with severe asthma who do not respond to approved therapies. Small molecule inhibitors, such as JAK-inhibitors, and monoclonal antibodies targeting mast cells, IL-1, IL-6, IL-33, TNFα, and OX40L are under investigation for their potential to modulate inflammation involved in refractory asthma. Understanding refractory asthma heterogeneity and identifying mediators involved are essential in developing therapeutic interventions for patients unresponsive to currently approved biologics. Further investigation is needed to develop personalized treatments based on these molecular insights to potentially offer more effective treatments for this complex disease.

Advances in non-type 2 severe asthma: from molecular insights to novel treatment strategies

Asthma is a prevalent pulmonary disease that affects more than 300 million people worldwide and imposes a substantial economic burden. While medication can effectively control symptoms in some patients, severe asthma attacks, driven by airway inflammation induced by environmental and infectious exposures, continue to be a major cause of asthma-related mortality. Heterogeneous phenotypes of asthma include type 2 (T2) and non-T2 asthma. Non-T2 asthma is often observed in patients with severe and/or steroid-resistant asthma. This review covers the molecular mechanisms, clinical phenotypes, causes and promising treatments of non-T2 severe asthma. Specifically, we discuss the signalling pathways for non-T2 asthma including the activation of inflammasomes, interferon responses and interleukin-17 pathways, and their contributions to the subtypes, progression and severity of non-T2 asthma. Understanding the molecular mechanisms and genetic determinants underlying non-T2 asthma could form the basis for precision medicine in severe asthma treatment.

Nrf2 Deficiency Accelerates IL-17-Dependent Neutrophilic Airway Inflammation in Asthmatic Mice

Asthma is a heterogeneous disease that can be broadly classified into type 2, which is primarily steroid-sensitive and eosinophilic, and non-type 2, which is primarily steroid-resistant and neutrophilic. While the mechanisms leading to the development of molecular-targeted therapies for type 2 asthma are being elucidated, much remains to be learned about non-type 2 asthma. To investigate the role of oxidative stress in refractory allergic airway inflammation, we compared asthma models generated by immunizing wild-type and nuclear factor erythroid-2-related factor 2 (Nrf2)-deficient mice with the house dust mite antigen. Both asthma models had similar levels of airway inflammation and hyperresponsiveness, but the Nrf2-deficient mice had increased oxidative stress and exacerbated neutrophilic airway inflammation compared with the wild-type mice. Type 2 cytokines and the expression of GATA3, a transcription factor that is important for Th2 cell differentiation, had decreased in Nrf2-deficient mice compared with the wild-type mice, whereas helper T (Th) 17 cytokines and the expression of RORγt, which is important for Th17 cell differentiation, had increased. Furthermore, the neutrophilic airway inflammation caused by Nrf2 deficiency was ameliorated by interleukin (IL)-17 neutralization. We have concluded that the disruption of the Nrf2-mediated antioxidant defense system contributed to the induction of Th17 differentiation and exacerbated allergic neutrophilic airway inflammation.

Weighted Breaths: Exploring Biologic and Non-Biologic Therapies for Co-Existing Asthma and Obesity

PURPOSE OF REVIEW

To discuss the effectiveness of biologics, some of which comprise the newest class of asthma controller medications, and non-biologics in the treatment of asthma co-existing with obesity.

RECENT FINDINGS

Our review of recent preliminary and published data from clinical trials revealed that obese asthmatics respond favorably to dupilumab, mepolizumab, omalizumab, and tezepelumab, which are biologics currently indicated as add-on maintenance therapy for severe asthma. Furthermore, clinical trials are ongoing to assess the efficacy of non-biologics in the treatment of obese asthma, including a glucagon-like peptide-1 receptor agonist, a Janus kinase inhibitor, and probiotics. Although many biologics presently indicated as add-on maintenance therapy for severe asthma exhibit efficacy in obese asthmatics, other phenotypes of asthma co-existing with obesity may be refractory to these medications. Thus, to improve quality of life and asthma control, it is imperative to identify therapeutic options for all existing phenotypes of obese asthma.

Association of Obesity and Severe Asthma in Adults

The incidence of obesity and asthma continues to enhance, significantly impacting global public health. Adipose tissue is an organ that secretes hormones and cytokines, causes meta-inflammation, and contributes to the intensification of bronchial hyperreactivity, oxidative stress, and consequently affects the different phenotypes of asthma in obese people. As body weight increases, the risk of severe asthma increases, as well as more frequent exacerbations requiring the use of glucocorticoids and hospitalization, which consequently leads to a deterioration of the quality of life. This review discusses the relationship between obesity and severe asthma, the underlying molecular mechanisms, changes in respiratory function tests in obese people, its impact on the occurrence of comorbidities, and consequently, a different response to conventional asthma treatment. The article also reviews research on possible future therapies for severe asthma. The manuscript is a narrative review of clinical trials in severe asthma and comorbid obesity. The articles were found in the PubMed database using the keywords asthma and obesity. Studies on severe asthma were then selected for inclusion in the article. The sections: 'The classification connected with asthma and obesity', 'Obesity-related changes in pulmonary functional tests', and 'Obesity and inflammation', include studies on subjects without asthma or non-severe asthma, which, according to the authors, familiarize the reader with the pathophysiology of obesity-related asthma.

Towards personalized medicine for the treatment of equine asthma

Although horses with asthma share similar clinical signs, the heterogeneity of the disease in terms of severity, triggering factors, inflammatory profile, and pathological features has hindered our ability to define biologically distinct subgroups. The recognition of phenotypes and endotypes could enable the development of precision medicine, including personalized, targeted therapy, to benefit affected horses. While in its infancy in horses, this review outlines the phenotypes of equine asthma and discusses how knowledge gained from targeted therapy in human medicine can be applied to evaluate the potential opportunities for personalized medicine in equine asthma and to suggest avenues for research to advance this emerging field.

Small extracellular vesicles derived from human mesenchymal stem cells prevent Th17-dominant neutrophilic airway inflammation via immunoregulation on Th17 cells

Type 17 helper T cells (Th17)-dominant neutrophilic airway inflammation is critical in the pathogenesis of steroid-resistant airway inflammation such as severe asthma. Small extracellular vesicles (sEV) derived from human mesenchymal stem cells (MSCs) display extensive therapeutic effects and advantages in many diseases. However, the role of MSC-sEV in Th17-dominant neutrophilic airway inflammation and the related mechanisms are still poorly studied. Here we found that MSC-sEV significantly alleviated the infiltration of inflammatory cells in peribronchial interstitial tissues and reduced levels of inflammatory cells, especially neutrophils, in bronchoalveolar lavage fluids (BALF) of mice with neutrophilic airway inflammation. Consistently, MSC-sEV significantly decreased levels of IL-17A in BALF and Th17 in lung tissues. Furthermore, we found that labelled MSC-sEV were taken up by human CD4+ T cells most obviously at 12 h after incubation, and distributed mostly in mouse lungs. More importantly, potential signaling pathways involved in the MSC-sEV mediated inhibition of Th17 polarization were found using RNA sequencing. Using Western blot, JAK2-STAT3 pathway was identified as an important role in the inhibition of Th17 polarization by MSC-sEV. We found that proteins in MSC-sEV were mostly involved in the therapeutic effects of MSC-sEV. In total, our study suggested that MSC-sEV could be a potential therapeutic strategy for the treatment of neutrophilic airway inflammation.

Allosteric inhibition of CXCR1 and CXCR2 abrogates Th2/Th17-associated Allergic Lung Inflammation in Mice

Background

IL4, IL5, IL13, and IL17-producing CD4 T helper 2 (Th2)-cells and IL17-producing CD4 T helper 17 (Th17)-cells contribute to chronic eosinophilic and neutrophilic airway inflammation in asthma and allergic airway inflammation. Chemokines and their receptors are upregulated in Th2/Th17-mediated inflammation. However, the ability of CXCR1 and CXCR2 modulate Th2 and Th17-cell-mediated allergic lung inflammation has not been reported.

Methods

Mice sensitized and challenged with cat dander extract (CDE) mount a vigorous Th2-Th17-mediated allergic lung inflammation. Allosteric inhibitor of CXCR1 and CXCR2, ladarixin was orally administered in this model. The ability of ladarixin to modulate allergen-challenge induced recruitment of CXCR1 and CXCR2-expressing Th2 and Th17-cells and allergic lung inflammation were examined.

Results

Allergen challenge in sensitized mice increased mRNA expression levels of Il4, Il5, Il13, Il6, Il1β, Tgfβ1, Il17, Il23, Gata3, and Rorc , and induced allergic lung inflammation characterized by recruitment of CXCR1- and CXCR2-expressing Th2-cells, Th17-cells, neutrophils, and eosinophils. Allosteric inhibition of CXCR1 and CXCR2 vigorously blocked each of these pro-inflammatory effects of allergen challenge. CXCL chemokines induced a CXCR1 and CXCR2-dependent proliferation of IL4, IL5, IL13, and IL17 expressing T-cells.

Conclusion

Allosteric inhibition of CXCR1 and CXCR2 abrogates blocks recruitment of CXCR1- and CXCR2-expressing Th2-cells, Th17-cells, neutrophils, and eosinophils in this mouse model of allergic lung inflammation. We suggest that the ability of allosteric inhibition of CXCR1 and CXCR2 to abrogate Th2 and Th17-mediated allergic inflammation should be investigated in humans.

Systemic IL-26 correlates with improved asthma control in children sensitized to dog allergen

BACKGROUND

Interleukin (IL)-26 is produced by T helper type 17 (Type 17) cells and exerts immunomodulatory plus antimicrobial effects. Previous studies show that local IL-26 concentrations in the airways are higher in patients with uncontrolled than in those with controlled asthma, and that this intriguing cytokine bears biomarker potential. Here, we determined how systemic IL-26 relates to allergen sensitization, asthma severity, and to IL-17 A in children.

METHODS

Serum samples were obtained from children with (n = 60) and without (n = 17) sensitization to dog allergen, and IL-26 and IL-17 A protein concentrations were measured using ELISA. Self-reported history, including medication use and validated symptom-based questionnaire scores, was recorded.

RESULTS

The serum concentrations of IL-26 were enhanced in allergen-sensitized subjects and correlated with those of IL-17 A in a positive manner. However, the IL-26 concentrations did not markedly differ between allergen-sensitized subjects with and without asthma, eczema, allergic rhinitis, or a history of food allergy. Notably, IL-26 concentrations correlated with increasing Asthma Control Test (ACT) scores in a positive manner and with inhaled corticosteroid in a negative manner, amongst sensitized subjects with asthma. Moreover, subjects with asthma requiring ≥ 1 course of oral corticosteroids in the preceding 12 months had decreased IL-26 concentrations.

CONCLUSION

This study forwards evidence that systemic IL-26, just like IL-17 A, is involved in allergen sensitization among children. The association of systemic IL-26 with improved asthma control is compatible with the cellular sources being recruited into the airways in severe asthma, which supports that this kinocidin bears potential as a biomarker and therapeutic target.

Evidence evaluated by European Food Safety Authority does not support lowering the temporary tolerable daily intake for bisphenol A

The European Food Safety Authority (EFSA) recently derived a tolerable daily intake (TDI) for bisphenol A (BPA) of 0.2 ng/kg bw/day. There are several issues with EFSA's hazard assessment review process, including that it was based on a limited subset of relevant studies. Multiple public commenters on EFSA's draft evaluation of BPA, including several European regulatory agencies, noted these issues, yet they were not adequately addressed by EFSA in the final evaluation. The TDI for BPA was based on an intermediate immunotoxicity endpoint in mice that has not been observed in other species; there is no evidence that it is a precursor event to any downstream pathological outcome. The TDI is several orders of magnitude lower than estimates of safe doses of BPA established by agencies worldwide, including EFSA's temporary TDI (t-TDI) for BPA established in 2015. Overall, the EFSA hazard assessment review process has led to a conclusion that there are low-dose effects of BPA based on very few, lower quality experimental animal studies. This conclusion is not supported by the totality of the available evidence, which includes multiple high-quality studies not considered by EFSA and indicates that the t-TDI established in 2015 is protective of human health.

New targets for type 2-low asthma

Asthma is characterized by airway obstruction and inflammation, and presents significant diagnostic and treatment challenges. The concept of endotypes has improved understanding of the mechanisms of asthma and has stimulated the development of effective treatment strategies. Sputum profiles may be used to classify asthma into two major inflammatory types: type 2-high (T2H) and type 2-low (T2L) asthma. T2H, characterized by elevated type 2 inflammation, has been extensively studied and several effective biologic treatments have been developed. However, managing T2L is more difficult due to the lack of reliable biomarkers for accurate diagnosis and classification. Additionally, conventional anti-inflammatory therapy does not completely control the symptoms of T2L; therefore, further research is needed to identify effective biologic treatments. This review provides new insights into the clinical characteristics and underlying mechanisms of severe T2L and investigates potential therapeutic approaches to control the disease.

Dual inhibition of airway inflammation and fibrosis by common β cytokine receptor blockade

BACKGROUND

Patients with severe asthma can present with eosinophilic type 2 (T2), neutrophilic, or mixed inflammation that drives airway remodeling and exacerbations and represents a major treatment challenge. The common β (βc) receptor signals for 3 cytokines, GM-CSF, IL-5, and IL-3, which collectively mediate T2 and neutrophilic inflammation.

OBJECTIVE

To determine the pathogenesis of βc receptor-mediated inflammation and remodeling in severe asthma and to investigate βc antagonism as a therapeutic strategy for mixed granulocytic airway disease.

METHODS

βc gene expression was analyzed in bronchial biopsy specimens from patients with mild-to-moderate and severe asthma. House dust mite extract and Aspergillus fumigatus extract (ASP) models were used to establish asthma-like pathology and airway remodeling in human βc transgenic mice. Lung tissue gene expression was analyzed by RNA sequencing. The mAb CSL311 targeting the shared cytokine binding site of βc was used to block βc signaling.

RESULTS

βc gene expression was increased in patients with severe asthma. CSL311 potently reduced lung neutrophils, eosinophils, and interstitial macrophages and improved airway pathology and lung function in the acute steroid-resistant house dust mite extract model. Chronic intranasal ASP exposure induced airway inflammation and fibrosis and impaired lung function that was inhibited by CSL311. CSL311 normalized the ASP-induced fibrosis-associated extracellular matrix gene expression network and strongly reduced signatures of cellular inflammation in the lung.

CONCLUSIONS

βc cytokines drive steroid-resistant mixed myeloid cell airway inflammation and fibrosis. The anti-βc antibody CSL311 effectively inhibits mixed T2/neutrophilic inflammation and severe asthma-like pathology and reverses fibrosis gene signatures induced by exposure to commonly encountered environmental allergens.

ST2-Mediated Neutrophilic Airway Inflammation: A Therapeutic Target for Patients With Uncontrolled Asthma

PURPOSE

Suppression of tumorigenicity 2 (ST2) has been proposed as the receptor contributing to neutrophilic inflammation in patients with type 2-low asthma. However, the exact role of ST2 in neutrophil activation remains poorly understood.

METHODS

A total of 105 asthmatic patients (classified into 3 groups according to control status: the controlled asthma [CA], partly-controlled asthma [PA], and uncontrolled asthma [UA] groups), and 104 healthy controls were enrolled to compare serum levels of soluble ST2 (sST2) and interleukin (IL)-33. Moreover, the functions of ST2 in neutrophils and macrophages (Mϕ) were evaluated ex vivo and in vivo.

RESULTS

Serum sST2 levels were significantly higher in the UA group than in the CA or PA groups (P < 0.05 for all) with a negative correlation between serum sST2 and forced expiratory volume in 1 second % (r = -0.203, P = 0.038). Significantly higher expression of ST2 receptors on peripheral neutrophils was noted in the UA group than in the PA or CA groups. IL-33 exerted its effects on the production of reactive oxygen species, the formation of extracellular traps from neutrophils, and Mϕ polarization/activation. In neutrophilic asthmatic mice, treatment with anti-ST2 antibody significantly suppressed proinflammatory cytokines (tumor necrosis factor-alpha and IL-17A) as well as the numbers of immune cells (neutrophils, Mϕ, and group 3 innate lymphoid cells) in the lungs.

CONCLUSIONS

These results suggest that IL-33 induces the activation of neutrophils and Mϕ via ST2 receptors, leading to neutrophilic airway inflammation and poor control status of asthma. ST2 could be a therapeutic target for neutrophilic airway inflammation in patients with UA.

Epithelial SIRT6 governs IL-17A pathogenicity and drives allergic airway inflammation and remodeling

Dysregulation of IL-17A is closely associated with airway inflammation and remodeling in severe asthma. However, the molecular mechanisms by which IL-17A is regulated remain unclear. Here we identify epithelial sirtuin 6 (SIRT6) as an epigenetic regulator that governs IL-17A pathogenicity in severe asthma. Mice with airway epithelial cell-specific deletion of Sirt6 are protected against allergen-induced airway inflammation and remodeling via inhibiting IL-17A-mediated inflammatory chemokines and mesenchymal reprogramming. Mechanistically, SIRT6 directly interacts with RORγt and mediates RORγt deacetylation at lysine 192 via its PPXY motifs. SIRT6 promotes RORγt recruitment to the IL-17A gene promoter and enhances its transcription. In severe asthma patients, high expression of SIRT6 positively correlates with airway remodeling and disease severity. SIRT6 inhibitor (OSS_128167) treatment significantly attenuates airway inflammation and remodeling in mice. Collectively, these results uncover a function for SIRT6 in regulating IL-17A pathogenicity in severe asthma, implicating SIRT6 as a potential therapeutic target for severe asthma.

Peripheral neutrophils and oxidative stress-associated molecules for predicting the severity of asthma: a cross-sectional study based on multidimensional assessment

Objectives

This study aims to explore the relationship between the severity of asthma and neutrophils and related oxidative stress-associated molecules in peripheral blood and induced sputum.

Methods

A total of 67 subjects were included in this study, namely, 25 patients with severe asthma and 42 patients with non-severe asthma. Clinical data, induced sputum and peripheral blood were collected. Lung function and molecules related to oxidative stress in induced sputum and peripheral blood of asthma patients were detected. The relationship between neutrophils and asthma severity was analyzed. HDAC2 mRNA and protein expression levels and HDAC2 activity were also analyzed. Multivariate logistic regression was performed to select statistically significant variables.

Results

The absolute value of neutrophils and percentage of neutrophils were higher in the severe asthma patients. These two values were used to predict the severity of asthma by ROC analysis, with the best cutoff values being 4.55 × 109/L (sensitivity 83.3%, specificity 64.0%) and 55.15% (sensitivity 54.8%, specificity 88.0%). The ROS concentration of neutrophils in the induced sputum samples and the 8-iso-PGF2α concentration in the peripheral blood samples were higher in the severe asthma group (P = 0.012; P = 0.044), whereas there was reduced HDAC2 protein activity in PBMCs (P < 0.001). A logistic equation and a nomogram were created to give a precise prediction of disease severity.

Conclusion

Oxidative stress is increased in severe asthma patients. Peripheral blood neutrophils and 8-iso-PGF2α can be used as biomarkers to predict the severity of asthma. A prediction model was created for evaluating asthma severity.

Risk of candidiasis associated with interleukin-17 inhibitors: Implications and management

The application of interleukin-17 (IL-17) inhibitors, including secukinumab, ixekizumab, brodalumab, and bimekizumab, are associated with elevated risk of candidiasis. These medications interfere with the IL-17 pathway, which is essential for maintaining mucosal barriers and coordinating the immune response against Candida species. The observational data and clinical trials demonstrate the increased incidence of candidiasis in individuals treated with IL-17 inhibitors. Brodalumab and bimekizumab pose a greater risk than secukinumab in eliciting candidiasis, whereas the data regarding ixekizumab are equivocal. Higher doses and prolonged treatment duration of IL-17 inhibitors increase the risk of candidiasis by compromising the immune response against Candida species. Prior to prescribing IL-17 inhibitors, healthcare professionals should comprehensively evaluate patients' medical histories and assess their risk factors. Patients should be educated on the signs and symptoms of candidiasis to facilitate early detection and intervention. Future research should focus on identifying the risk factors associated with candidiasis in patients receiving IL-17 inhibitors. Prospective studies and long-term surveillance are required to explore the impact of specific inhibitors on the incidence and severity of candidiasis and to evaluate the effectiveness of combination therapies, such as concurrent use of IL-17 inhibitors and prophylactic antifungal agents.

Blood transcriptomic signature in type-2 biomarker-low severe asthma and asthma control

BACKGROUND

Patients with type-2 (T2) cytokine-low severe asthma often have persistent symptoms despite suppression of T2 inflammation with corticosteroids.

OBJECTIVES

We sought to analyze whole blood transcriptome from 738 samples in T2-biomarker-high/-low patients with severe asthma to relate transcriptomic signatures to T2 biomarkers and asthma symptom scores.

METHODS

Bulk RNA-seq data were generated for blood samples (baseline, week 24, week 48) from 301 participants recruited to a randomized clinical trial of corticosteroid optimization in severe asthma. Unsupervised clustering, differential gene expression analysis, and pathway analysis were performed. Patients were grouped by T2-biomarker status and symptoms. Associations between clinical characteristics and differentially expressed genes (DEGs) associated with biomarker and symptom levels were investigated.

RESULTS

Unsupervised clustering identified 2 clusters; cluster 2 patients were blood eosinophil-low/symptom-high and more likely to be receiving oral corticosteroids (OCSs). Differential gene expression analysis of these clusters, with and without stratification for OCSs, identified 2960 and 4162 DEGs, respectively. Six hundred twenty-seven of 2960 genes remained after adjusting for OCSs by subtracting OCS signature genes. Pathway analysis identified dolichyl-diphosphooligosaccharide biosynthesis and assembly of RNA polymerase I complex as significantly enriched pathways. No stable DEGs were associated with high symptoms in T2-biomarker-low patients, but numerous associated with elevated T2 biomarkers, including 15 that were upregulated at all time points irrespective of symptom level.

CONCLUSIONS

OCSs have a considerable effect on whole blood transcriptome. Differential gene expression analysis demonstrates a clear T2-biomarker transcriptomic signature, but no signature was found in association with T2-biomarker-low patients, including those with a high symptom burden.

Intrinsically bioactive and biomimetic nanoparticle-derived therapies alleviate asthma by regulating multiple pathological cells

Asthma is a serious global public health concern. Airway neutrophilic inflammation is closely related to severe asthma, for which effective and safe therapies remain to be developed. Here we report nanotherapies capable of simultaneously regulating multiple target cells relevant to the pathogenesis of neutrophilic asthma. A nanotherapy LaCD NP based on a cyclic oligosaccharide-derived bioactive material was engineered. LaCD NP effectively accumulated in the injured lungs of asthmatic mice and mainly distributed in neutrophils, macrophages, and airway epithelial cells after intravenous or inhalation delivery, thereby ameliorating asthmatic symptoms and attenuating pulmonary neutrophilic inflammation as well as reducing airway hyperresponsiveness, remodeling, and mucus production. Surface engineering via neutrophil cell membrane further enhanced targeting and therapeutic effects of LaCD NP. Mechanistically, LaCD NP can inhibit the recruitment and activation of neutrophils, especially reducing the neutrophil extracellular traps formation and NLRP3 inflammasome activation in neutrophils. Also, LaCD NP can suppress macrophage-mediated pro-inflammatory responses and prevent airway epithelial cell death and smooth muscle cell proliferation, by mitigating neutrophilic inflammation and its direct effects on relevant cells. Importantly, LaCD NP showed good safety performance. Consequently, LaCD-derived multi-bioactive nanotherapies are promising for effective treatment of neutrophilic asthma and other neutrophil-associated diseases.