Allergic Endotypes and Phenotypes of Asthma

IgE-Mediated Activation of Mast Cells and Basophils in Health and Disease

Type 2-mediated immune responses protect the body against environmental threats at barrier surfaces, such as large parasites and environmental toxins, and facilitate the repair of inflammatory tissue damage. However, maladaptive responses to typically nonpathogenic substances, commonly known as allergens, can lead to the development of allergic diseases. Type 2 immunity involves a series of prototype TH2 cytokines (IL-4, IL-5, IL-13) and alarmins (IL-33, TSLP) that promote the generation of adaptive CD4+ helper Type 2 cells and humoral products such as allergen-specific IgE. Mast cells and basophils are integral players in this network, serving as primary effectors of IgE-mediated responses. These cells bind IgE via high-affinity IgE receptors (FcεRI) expressed on their surface and, upon activation by allergens, release a variety of mediators that regulate tissue responses, attract and modulate other inflammatory cells, and contribute to tissue repair. Here, we review the biology and effector mechanisms of these cells, focusing primarily on their role in mediating IgE responses in both physiological and pathological contexts.

Correlation between total IgE level and asthma symptom severity in hospitalized children

Background

Status asthmaticus is a common reason for hospitalization and pediatric intensive care unit (PICU) admission among children. While previous studies have demonstrated a correlation between elevated IgE levels and asthma severity in outpatient settings, studies analyzing IgE levels in an inpatient cohort are limited.

Objective

We examined the relationship between baseline IgE levels and symptom severity, maximum respiratory support, and PICU and hospital length of stay in an inpatient pediatric cohort.

Methods

This was a single-center retrospective chart review of children admitted to the Children's Hospital at Montefiore with status asthmaticus as their primary diagnosis. The primary goal was to determine the relationship between baseline IgE levels and severity of illness at time of admission. Secondary outcomes included maximum respiratory support, and PICU and hospital length of stay.

Results

We identified a statistically significant difference (P = .043) in baseline IgE levels between the PICU (median, 608 U/mL) and floor groups (405 IU/mL). There was a positive correlation between IgE level and PICU length of stay (P = .004).

Conclusion

Elevated baseline IgE level is correlated with higher asthma symptom severity when hospitalized and with longer PICU length of stay. Our study adds to the growing body of evidence that those with high baseline IgE levels are at risk of having severe asthma symptomology.

Worse lung function, more allergic sensitization but less blood eosinophilia in elderly patients with long-standing versus late-onset asthma

BACKGROUND

Asthma in the elderly is usually considered homogeneous and non-atopic.

OBJECTIVE

To compare clinical, functional and immunological features between elderly asthmatics with long-standing asthma (LSA) and those with late-onset asthma (LOA).

METHODS

Eighty-two asthmatics older than 64 were included into LSA (asthma onset before age 40; n = 46) and LOA (asthma onset from 40 years of age on; n = 36) groups. Asthma treatment and comorbidities were recorded. All individuals underwent the asthma control questionnaire-7 (ACQ-7) and cognitive impairment screening (Mini-Mental State Examination). Inhaler technique was assessed by checklists; the Morisky Medication Adherence Scale-8 was used to assess adherence to treatment. Spirometry, skin prick tests (SPTs), induced sputum and blood eosinophil counts were performed.

RESULTS

We found high frequencies of cognitive impairment, poor inhaler technique and low adherence to treatment in both groups, which had good disease control (ACQ-7 scores: 1.20 ± 0.74 versus 1.11 ± 0.89; p = 0.67, respectively). The LSA group had more severe airway obstruction (FEV1(% predicted): 62.04 ± 19.50 versus 77.15 ± 18.74, p < 0.01; FEV1/FVC: 0.59 ± 0.10 versus 0.69 ± 0.09, p < 0.01); higher frequency of positive SPTs (65.6% versus 18.8%, p = 0.001); and lower frequency of blood eosinophilia (45.7% versus 77.1%, p = 0.004) than the LOA group. No differences in sputum cell counts or inflammatory profiles were found between the groups. Ninety percent of the individuals studied had at least one feature of Type 2 asthma.

CONCLUSION

LSA and LOA phenotypes differ substantially. That should be accounted for in research and clinical practice grounds.

Short-Term Effect of Ozone Exposure on Small Airway Function in Adult Asthma Patients with PM2.5 Exacerbating the Effect

Ambient ozone (O3) has been associated with asthma symptoms and exacerbations. The impairment of small airway function leads to worse control, more frequent exacerbations and increased bronchial hyperresponsiveness in asthma patients. However, the impact of O3 on small airway function in asthma remains underexplored. Our longitudinal observational study enrolled 312 adult asthma patients and collected a total of 399 lung function records. We applied a linear mixed-effects model to analyze the associations between ambient O3 exposure at different lag days (from lag0 to lag7) and small airway function parameters, including forced expiratory flow (FEF) at 50%, 75% and 25-75% of forced vital capacity (FVC) predicted (FEF50%pred, FEF75%pred and FEF25-75%pred). Significant associations were found between ambient O3 levels and reductions in FEF50%pred, FEF75%pred and FEF25-75%pred, with the effects being most pronounced for exposure at lag0. Further analysis indicated that fine particulate matter (PM2.5) and its main components, including black carbon, organic matter, sulfate, nitrate and ammonium, exacerbated the detrimental effects of O3 on small airway function. Additionally, stronger O3 effects were found in asthma patients aged over 40 years, those with a body mass index ≥ 25 kg/m2, and individuals with allergic asthma. These results provide new insights into the impact of O3 on small airway function, offering fresh insights into asthma exacerbation mechanisms and underscoring the critical need to address composite pollutants for more effective asthma management.

Extracellular Vesicles in Asthma: Intercellular Cross-Talk in TH2 Inflammation

Asthma is a complex, multifactorial inflammatory disorder of the airways, characterized by recurrent symptoms and variable airflow obstruction. So far, two main asthma endotypes have been identified, type 2 (T2)-high or T2-low, based on the underlying immunological mechanisms. Recently, extracellular vesicles (EVs), particularly exosomes, have gained increasing attention due to their pivotal role in intercellular communication and distal signaling modulation. In the context of asthma pathobiology, an increasing amount of experimental evidence suggests that EVs secreted by eosinophils, mast cells, dendritic cells, T cells, neutrophils, macrophages, and epithelial cells contribute to disease modulation. This review explores the role of EVs in profiling the molecular signatures of T2-high and T2-low asthma, offering novel perspectives on disease mechanisms and potential therapeutic targets.

Association Between Visceral Adipose Tissue and Chronic Respiratory Diseases: A Two-Sample Multivariable Mendelian Randomization Study in European Population

Background

The relationship between obesity and some respiratory diseases has been well documented. However there have been few studies on the association between visceral adipose tissue (VAT) and chronic respiratory diseases (CRDs), it remains unclear whether VAT is causally associated with CRDs.

Methods

We used two-sample Mendelian randomization (MR) to illuminate the effects of VAT on four CRDs: chronic obstructive pulmonary disease (COPD), allergic asthma, interstitial lung disease (ILD), and sarcoidosis. Inverse variance weighted (IVW) served as the primary assessment method. MR Egger, weighted median, Simple mode and Weighted mode were the supplementary methods for MR analysis. We used multivariate MR analysis to adjust for the effect of body mass index (BMI) on outcomes, Egger intercept, MR-pleiotropy residual sum and outlier, and leave-one-out analysis to confirm the MR results' consistency.

Results

Genetically-predicted VAT was associated with an increased risk of COPD (OR = 1.56; 95% CI: 1.34-1.82; P = 1.16×10-8), allergic asthma (OR = 1.44; 95% CI: 1.20-1.73; P = 8.63×10-5), and ILD (OR = 1.15; 95% CI: 1.04-1.26; P = 4.62×10-3). However, there was limited evidence to support an association between VAT and sarcoidosis. In multivariate MR analysis, VAT's associations with COPD, allergic asthma, and ILD persisted after adjusting for BMI.

Conclusion

This study provides evidence for a potential causal relationship between VAT and COPD, allergic asthma, and ILD; these relationships were independent of the effect of BMI.

Safranal restores RUNX3-mediated immunoregulation by inhibiting the NLRP3 inflammasome in allergic asthma

Safranal is an active ingredient with pharmacological anti-inflammatory effects derived from Crocus sativus essential oil. To explore the comprehensive effects of Safranal on airway inflammation, airway hyperreactivity, and remodeling and its potential mechanisms through the allergic asthma model, an in vitro model of ASMC cells stimulated by TNF-α was established. The cells were transfected with si-RUNX3 and RUNX3 overexpression plasmids, and DEX was used as a positive control. The expression of RUNX3 was detected by western blot and immunofluorescence. The levels of inflammatory factors were measured by ELISA, while flow cytometry detected the anti-apoptotic effects and ROS production. Subsequently, OVA-sensitized WT mice and RUNX3-KO mice were administered with DEX and Safranal for 2 weeks to establish a mouse model of allergic asthma, and changes in airway hyperresponsiveness, inflammatory manifestations, and airway remodeling were detected. The mechanism of Safranal was verified by detecting the expression of RUNX3, inflammation, and fibrosis-related proteins in the lung tissues. By modulating the NLRP3/Caspase-1 pathway, Safranal significantly alleviated the negative effects caused by RUNX3 suppression in vivo and in vitro. We propose that Safranal is a potential active compound for the treatment of asthma, and its clinical application value in allergic asthma should be further explored.

Zhichuanling injection improves bronchial asthma by attenuation airway inflammation and epithelia-mesenchymal transition

ETHNOPHARMACOLOGICAL RELEVANCE

Zhichuanling (ZCL) Injection, is a compound formulation containing extracts of mahuang (Herba Ephedrae, dried stem or aerial part of Ephedra sinica Stapf), bitter almond (Semen Armeniacae Amarum, seeds of Prunus armeniaca var. sibirica (L.) K. Koch), yangjinhua (flower of Datura metel L.) and Fructus Forsythiae (fruits of Forsythia suspensa (Thunb.) Vahl). Intramuscular injection of ZCL has been used in the clinical practice to control asthma. The aerosol inhalation of ZCL has been shown to be effective on allergic bronchial asthma. However, the underlying mechanisms remain established.

AIM OF THE STUDY

To investigate the underling mechanism by which ZCL inhibits the pathogenesis of bronchial asthma.

METHODS

The guinea pig tracheal rings and human bronchial epithelial (16HBE) cells were used to assess ZCL's impact on acetylcholine (Ach) induced tracheal contraction, tumor necrosis factor α (TNF-α) induced bronchial inflammation, and transforming growth factor-β1 (TGF-β1) induced airway remodeling. Cell viability and gene expression were assessed using MTT assays, qPCR. RNA-seq (gene expression analysis) was employed to explore the novel mechanisms of ZCL in OVA-induced bronchial asthma.

RESULTS

In this study, we found that ZCL reduces Ach-induced contraction of isolated guinea pig trachea, suppress TNF-α-induced interleukin (IL)-1β, IL-6, and IL-8 and TGF-β1-induced E-cadherin, α-SMA, Vimentin, N-cadherin mRNA expression in the 16HBE. Transcriptomic analysis of lung tissue from mice with OVA-induced bronchial asthma suggests that ZCL may alleviate asthma symptoms by modulating BPIFA1, HIF3Α, CTXN3, GRFA3, PPEF1, KSR2, and CDSN.

CONCLUSION

ZCL alleviates asthma by suppressing tracheal contractions, inflammation, and epithelial-to-mesenchymal transition. ZCL effect on asthma is likely through the upregulation of BPIFA1 expression thus providing the molecular insight for the treatment of asthma. The findings suggest that ZCL holds promise as a asthma therapeutic approach, and further research is needed to explore its full clinical potential. Future studies should focus on optimizing dosage, evaluating long-term efficacy, and investigating potential synergistic effects with existing treatments to enhance asthma management and patient outcomes.

Effect of the gut microbiome, skin microbiome, plasma metabolome, white blood cells subtype, immune cells, inflammatory proteins, and inflammatory cytokines on asthma: a two-sample Mendelian randomized study and mediation analysis

Background

Asthma is a chronic inflammatory disorder arising from incompletely understood heterogenic gene-environment interactions. This study aims to investigate causal relationships among gut microbiota, skin microbiota, plasma metabolomics, white blood cells subtype, immune cells, inflammatory proteins, inflammatory cytokines, and asthma.

Methods

First, two-sample Mendelian randomization analysis was used to identify causal relationships. The summary statistics of 412 gut microbiota traits (N = 7 738), 150 skin microbiota traits (N = 579), 1 400 plasma metabolite traits (N = 8 299), white blood cells subtype counts (N = 746 667), 731 immune cell traits (N = 3 669), 91 circulating inflammatory proteins (N = 14 744), 41 inflammatory cytokine traits (N = 8 293), and asthma traits (N = 244 562) were obtained from publicly available genome-wide association studies. Inverse-variance weighted regression was used as the primary Mendelian randomization method. A series of sensitivity analyses was performed to test the robustness of causal estimates. Subsequently, mediation analysis was performed to identify the pathway from gut or skin microbiota to asthma mediated by plasma metabolites, immune cells, and inflammatory proteins.

Results

Mendelian randomization revealed the causal effects of 31 gut bacterial features (abundances of 19 bacterial pathways and 12 microbiota), 10 skin bacterial features, 108 plasma metabolites (81 metabolites and 27 ratios), 81 immune cells, five circulating inflammatory proteins, and three inflammatory cytokines and asthma. Moreover, the mediation analysis results supported the mediating effects of one plasma metabolite, five immunophenotypes, and one inflammatory protein on the gut or skin microbiota in asthma pathogenesis.

Conclusion

The findings of this study support a causal relationship among gut microbiota, skin microbiota, plasma metabolites, immune cells, inflammatory proteins, inflammatory cytokines, and asthma. Mediating pathways through which the above factors may affect asthma were proposed. The biomarkers and mediation pathways identified in this work provide new insights into the mechanism of asthma and contribute to its prevention and treatment.

Degradation of IL-4Ralpha by Immunoproteasome: implication in airway type 2 inflammation and hyperresponsiveness

Introduction

Immunoproteasome (IP) is induced by pro-inflammatory stimuli such as interferon gamma to regulate inflammation and immunity. Asthma patients with airway type 2 high inflammation (e.g., IL-13) demonstrate more eosinophils and airway hyperresponsiveness (AHR) with less interferon gamma. The role of IP in regulating airway eosinophilic inflammation and AHR has not been investigated.

Methods

This study was aimed to determine how IP regulates type 2 inflammation and AHR using LMP7 (a subunit of IP) deficient mouse lungs, precision-cut lung slices (PCLS), and cultured human airway epithelial cells treated with IL-13 in the absence or presence of an IP inhibitor ONX-0914 or exogenous IP.

Results

LMP7 KO mouse lungs had significantly more IL-4Rα protein expression than the wildtype (WT) mice. Following IL-13 treatment in PCLS, LMP7 KO mice had significantly more airway contraction than WT mice, which was coupled with increased eotaxin-2 levels. IP inhibition by ONX-0914 in IL-13 treated human airway epithelial cells resulted in significantly more IL-4Rα protein expression and eotaxin-3 release. IP inhibition in human PCLS significantly increased AHR.

Conclusion

Collectively, these data demonstrated that IP promotes degradation of IL-4Rα, while inhibits type 2 inflammation and AHR. Enhancement of IP expression or activity may serve as an alternative approach to reduce the severity of type 2 inflammation and AHR.

Extracellular Vesicles for Disease Treatment

Traditional drug therapies suffer from problems such as easy drug degradation, side effects, and treatment resistance. Traditional disease diagnosis also suffers from high error rates and late diagnosis. Extracellular vesicles (EVs) are nanoscale spherical lipid bilayer vesicles secreted by cells that carry various biologically active components and are integral to intercellular communication. EVs can be found in different body fluids and may reflect the state of the parental cells, making them ideal noninvasive biomarkers for disease-specific diagnosis. The multifaceted characteristics of EVs render them optimal candidates for drug delivery vehicles, with evidence suggesting their efficacy in the treatment of various ailments. However, poor stability and easy degradation of natural EVs have affected their applications. To solve the problems of poor stability and easy degradation of natural EVs, they can be engineered and modified to obtain more stable and multifunctional EVs. In this study, we review the shortcomings of traditional drug delivery methods and describe how to modify EVs to form engineered EVs to improve their utilization. An innovative stimulus-responsive drug delivery system for EVs has also been proposed. We also summarize the current applications and research status of EVs in the diagnosis and treatment of different systemic diseases, and look forward to future research directions, providing research ideas for scholars.

Intranasal delivery of extracellular vesicles: A promising new approach for treating neurological and respiratory disorders

BACKGROUND

Extracellular vesicles (EVs) are membrane vesicles secreted by all types of cells, including bacteria, animals, and plants. These vesicles contain proteins, nucleic acids, and lipids from their parent cells and can transfer these components between cells. EVs have attracted attention for their potential use in diagnosis and therapy due to their natural properties, such as low immunogenicity, high biocompatibility, and ability to cross the blood-brain barrier. They can also be engineered to carry therapeutic molecules. EVs can be delivered via various routes. The intranasal route is particularly advantageous for delivering them to the central nervous system, making it a promising approach for treating neurological disorders.

SCOPE OF REVIEW

This review delves into the promising potential of intranasally administered EVs-based therapies for various medical conditions, with a particular focus on those affecting the brain and central nervous system. Additionally, the potential use of these therapies for pulmonary conditions, cancer, and allergies is examined, offering a hopeful outlook for the future of medical treatments.

MAJOR CONCLUSIONS

The intranasal administration of EVs offers significant advantages over other delivery methods. By directly delivering EVs to the brain, specifically targeting areas that have been injured, this administration proves to be highly efficient and effective, providing reassurance about the progress in medical treatments. Intranasal delivery is not limited to brain-related conditions. It can also benefit other organs like the lungs and stimulate a mucosal immune response against various pathogens due to the highly vascularized nature of the nasal cavity and airways. Moreover, it has the added benefit of minimizing toxicity to non-targeted organs and allows the EVs to remain longer in the body. As a result, there is a growing emphasis on conducting clinical trials for intranasal administration of EVs, particularly in treating respiratory tract pathologies such as coronavirus disease.

Influence of aeroallergen sensitization and nasal polyposis on mepolizumab response in eosinophilic severe asthma

Background: Studies on the impact of comorbidities on treatment responses in severe eosinophilic asthma (SEA) are limited. This study was a real-world investigation into how the presence or absence of nasal polyps (NP) and sensitivity to aeroallergens influence the outcomes of mepolizumab therapy. Methods: In this retrospective study, data obtained from patients with SEA and who received at least 6 months of mepolizumab treatment were analyzed. The patients were initially divided into two groups based on the presence of NPs. Within these two groups, the patients were further categorized into subgroups according to the presence of aeroallergen sensitivity (AE). Asthma-related outcomes in the resulting four groups were evaluated both before mepolizumab treatment and during the follow-up period. Results: Among the 36 patients with NPs, 14 (38.8%) had AE (NP+AE+), whereas 22 (61.2%) did not (NP+AE-). Of the 35 patients without NPs, 17 (48.5%) had AE (NP-AE+), and 18 (51.5%) did not (NP-AE-). The presence of NPs, independent of AE, was significantly associated with an increase in asthma exacerbations and oral corticosteroid (OCS) use before treatment (p < 0.001). In the NP+AE+ group, the baseline Asthma Control Test (ACT) score was lower, and the number of hospitalizations was significantly higher (p < 0.001). After mepolizumab treatment, all four groups showed significant reductions in asthma-related exacerbations, hospitalizations, and OCS use. Furthermore, ACT scores and pulmonary function test parameters significantly improved. There were limited differences in asthma improvements among the groups, with the NP+AE+ group showing a significant increase in ACT scores and a reduction in hospitalizations compared with the other groups (p < 0.001). Conclusion: Mepolizumab significantly reduced asthma exacerbations, hospitalizations, and OCS use in the patients with SEA with four different phenotypes. Analysis of these findings suggests that mepolizumab provides real-world benefits regardless of the presence or absence of NPs and AE.

PM2.5 exposure deteriorates Th1/Th2 balance in pediatric asthma by downregulating ALKBH5 and enhancing SRSF1 m6A methylation

Accumulating evidence has shown that long-term exposure to particulate matter with aerodynamic diameter of less than 2.5 μm (PM2.5) causes Th1/Th2 imbalance and increases the risk of allergic asthma (AA) in children. However, the mechanism underlying such effect remains elusive. Here, an AA mouse model was developed by intranasal administration of ovalbumin (OVA) and uncovered that OVA-sensitized mice exhibited pathological damage of lung tissues, mucus production, augmented serum IgE levels, enhanced Th2 cells and associated cytokine levels, and diminished Th1 cells and associated cytokine levels. Meanwhile, OVA induction led to upregulation of SRSF1 in mice. Moreover, shRNA-mediated knockdown of SRSF1 suppressed AA and Th1/Th2 imbalance in OVA-sensitized mice. After PM2.5 exposure, AA and Th1/Th2 imbalance were exacerbated and SRSF1 expression was increased in OVA-sensitized mice. Mechanistic experiments demonstrated that PM2.5-mediated inhibition of ALKBH5 expression augmented SRSF1 m6A modification in human bronchial epithelial cells treated with house dust mite. In this process, the m6A-reading protein YTHDF1 bound to SRSF1 mRNA and increased its stability. Furthermore, ALKBH5 overexpression neutralized PM2.5-aggravated Th1/Th2 imbalance in OVA-sensitized mice. Altogether, PM2.5 fosters Th1/Th2 imbalance in pediatric asthma by increasing SRSF1 m6A methylation through ALKBH5 downregulation.

Zyxin-a novel detrimental target, is inhibited by Saikosaponin A during allergic asthma

BACKGROUND

Allergic asthma is a heterogeneous disease involving numerous inflammatory cells. Mast cell (MC) plays a key role during allergic asthma. Saikosaponin A (SSA) inhibits MC activation and ameliorates allergic asthma, however, its underlying mechanism remains unclear. This study aims to identify SSA-binding proteins and reveal their functions.

METHODS

C57BL/6J mice were used to establish allergic asthma models to evaluate therapeutic effect of SSA. Protein microarray, RNA-seq, surface plasmon resonance (SPR), and pull-down assay were used to explore and validate the binding proteins of SSA. The functions of Zyxin were explored by knockdown and overexpression in LAD2. Zyxin knockout mice were constructed to investigate the role of Zyxin in allergic asthma.

RESULTS

SSA alleviates allergic asthma and inhibits MC activation. Zyxin was confirmed as a binding protein of SSA. In vitro experiments proved the crucial role of Zyxin in mast cell exocytosis. Zyxin Ser142/143 is phosphorylated during MC activation, which can be inhibited by SSA. In vivo studies showed that Zyxin expression in MC has detrimental effects, while its deficiency ameliorates allergic asthma.

CONCLUSION

Our results verified the detrimental effect of Zyxin in allergic asthma for the first time. We also innovatively demonstrated that SSA exerts inhibitory effects on MC activation and allergic asthma by directly binding to and inhibiting Zyxin phosphorylation.

Polymerized Molecular Allergoid Alt a1: Effective SCIT in Pediatric Asthma Patients

Background: Allergy to Alternaria alternata (Alt a), although often underdiagnosed, is a significant global health issue. In the allergen immunotherapy (AIT) field, novel therapeutic strategies are emerging, particularly with the advent of polymerized allergoids. This study aims to evaluate the efficacy of subcutaneous immunotherapy (SCIT) based on these innovative molecules in children with respiratory allergies, assessing clinical and functional parameters. Methods: We enrolled 42 patients aged between 6 and 16 years, all of whom had allergic rhinitis (AR) and concomitant asthma and all of whom were monosensitized to Alt a. Between December 2020 and December 2021, 17 patients initiated SCIT with Modigoid® for Alt a1, while 25 patients continued with standard therapy. At the initial visit (T0), all the patients underwent nasal and bronchial evaluation, including exhaled nitric oxide (eFeNO) measurement and spirometry. The Asthma Control Test (ACT) was used to evaluate the control of asthma symptoms. Patients were followed up every 6 months, with a comprehensive re-evaluation at 24 months (T1) replicating the initial assessments. Results: After 24 months of SCIT with the new polymerized molecular allergoid Alt a1 (Modigoid®), children showed a statistically significant reduction in eFeNO levels, improved FEV1 values, and enhanced ACT scores. Conclusions: SCIT with the new molecular allergoid Alt a1 significantly improves functional parameters (FEV1 and eFeNO) and subjective asthma symptoms (ACT scores) in children with AR and objective asthma signs. This treatment represents an effective preventive strategy that can be used to halt the progression of the classic atopic march from AR to asthma and potentially reverse the atopic march.

Bioinformatics and Network Pharmacology Identify the Therapeutic Role of Guominkang in Allergic Asthma by Inhibiting PI3K/Akt Signaling

Background

As a classical regulating formula, Guominkang (GMK) has been extensively employed in clinical practice to treat the allergic asthma (AA) and alleviate allergy symptoms, however, the underlying mechanism remains elusive. The aim of this study was to explored the mechanism of action through which GMK combats AA.

Methods

Potential target genes for the compounds were identified from the database and subjected to functional enrichment analysis. Subsequently, a protein-protein interaction (PPI) network was constructed in order to screen the core target and confirmed by molecular docking. An asthma model was further developed in mice and airway hyperresponsiveness and lung pathological changes were observed following drug administration. The expression of PI3K and AKT proteins in lung tissues was then detected by Western blotting. Subsequently, the GSE104468 data were normalised and visualised using the R language, compared to the PI3K-Akt pathway gene set to identify overlapping genes, constructed a PPI network and analysed correlations between genes.

Results

267 compounds and 475 disease-relevant GMK targets have been obtained, primarily in the areas of chemokine binding, drug binding, and PI3K-Akt pathway modulation. Molecular docking simulations revealed that predicted targets (PI3K, TNF, IL6, AKT1, SRC, TP53, and STAT3) could be closely bonded with component of GMK. According to in vivo experiments, GMK could reduce mucus obstruction and airway inflammation (P < 0.05), decrease airway hyperresponsiveness (P < 0.05), and inhibited the PI3K-Akt pathway (P < 0.05). After normalising the genes in the dataset between AA and healthy individuals, GO showed that 388 DEGs were associated with PI3K/AKT signaling pathway. The PPI network showed that the overlapping gene were located in the centre of asthma-associated network and that exhibited a correlation with the PI3K-Akt signaling pathway.

Conclusion

Based on our findings, GMK potentially acts via the PI3K/Akt pathway and alleviates allergic symptoms in AA.

Eosinophil-Driven vs. Eosinophil-Associated Severe Asthma: Practical Implications for Target Treatment

Severe asthma (SA) is a chronic inflammatory condition affecting approximately 10% of asthmatic patients, and eosinophils are considered key pathogenetic actors in a significant number of patients. Biological therapies have been demonstrated to improve asthma control by decreasing exacerbation rates and reducing the use of oral corticosteroids. In this context, phenotyping and endotyping patients with SA is essential for selecting the most effective therapeutic approach. For this purpose, biomarkers such as IgE, absolute blood eosinophil count, and fractional exhaled nitric oxide (FeNO) are crucial in defining a patient's inflammatory profile. Their integration provides a framework for classifying asthma into T2-high, T2-mild, or T2-low categories, guiding personalized treatment strategies. By incorporating multiple biomarkers into a unified model, it is possible to better stratify patients and optimize biologic therapy selection, paving the way for improved outcomes in SA management. This review aims to evaluate the role of phenotyping and endotyping SA patients, with particular attention to the impact of eosinophilic inflammation and combinatory biomarkers on decision-making processes for the selection of biological therapies.

Predictors of Friendship Skills for Adolescents with Asthma: An Analysis of Parent Report on the 2022 National Survey of Children's Health

BACKGROUND/OBJECTIVES

This study assesses parent reports of adolescent- and parent-level factors related to friendships among adolescents with asthma. This study serves to inform physicians and other health care professionals of factors related to difficulties making friends for adolescents with asthma, providing information from parent reports to identify risk and resilience factors related to friendships.

METHODS

Adolescents aged 12-17 years with current asthma from the 2022 National Survey of Children's Health (NSCH) were selected for the study (n = 1812). A weighted logistic regression analysis was performed to explore predictors related to making and keeping friends. Adolescent-level predictors were asthma severity, allergies, body mass index, having behavioral problems, and adolescent sex and race/ethnicity (non-Hispanic White, and others, including Hispanic). Parent-level predictors were parent stress and coping.

RESULTS

Adolescents who were female, non-Hispanic White, had moderate/severe asthma symptoms, had current allergies, were overweight, and had behavioral problems were more likely to have difficulty making and keeping friends than adolescents who were male, non-White, had mild asthma, did not have allergies, were a normal weight or underweight, and did not have behavioral problems. Parents who reported difficulty coping with parenthood and its associated stressors were more likely to report that their adolescents had difficulty making friends.

CONCLUSIONS

Pediatric moderate-to-severe asthma patients whose parents had difficulty coping with stress were more likely to exhibit greater difficulty making and keeping friends. Health care professionals managing these patients should incorporate questions into their history that address behavioral problems and parental household stress growing up to determine optimal strategies for improving friendship relationships. Whether this strategy leads to better asthma control and outcomes requires further investigation. In future studies, case studies with information about changes in friendships over time for adolescents with asthma should be carried out. The case studies could potentially highlight social strategies to use to improve friendship skills, and ultimately friendship-making for this vulnerable group.

Effect of PM2.5 exposure on susceptibility to allergic asthma in elderly rats treated with allergens

Fine particulate matter 2.5 (PM2.5) is a prevalent atmospheric pollutant that is closely associated with asthma. Elderly patients have a high incidence of asthma with a long course of illness. Our previous studies revealed that exposure to PM2.5 diminishes lung function and exacerbates lung damage in elderly rats. In the present study, we investigated whether PM2.5 exposure influences susceptibility to allergic asthma in elderly rats. Brown-Norway elderly rats were treated with ovalbumin (OVA) for different durations before and after PM2.5 exposure. The results from pulmonary function tests and histopathology indicated that early exposure to allergens prior to PM2.5 exposure increased susceptibility to airway hyperresponsiveness and led to severe lung injury in elderly asthmatic rats. Cytokine microarray analysis demonstrated that the majority of cytokines and chemokines were upregulated in OVA-treated rats before and after PM2.5 exposure. Cytological examination showed no change in eosinophil (EOS) counts, yet the amounts of neutrophils (NEU), white blood cells (WBC), lymphocytes (LYM), and monocytes (MON) in the lung lavage fluid of OVA-treated rats were significantly higher than those in control rats before and after PM2.5 exposure, suggesting that PM2.5 affects noneosinophilic asthma in elderly rats. ELISA results from the plasma and lung lavage fluid revealed that the levels of IgG1, IgE, IgG2a and IgG2b were significantly elevated in OVA-treated rats, whereas the level of IgG2b in the lung lavage fluid was significantly lower in rats treated with OVA prior to PM2.5 exposure compared to those treated afterward. A non-targeted metabolomic analysis of plasma identified 202 metabolites, among which 31 metabolites were differentially abundant. Ten metabolites and 11 metabolic pathways were uniquely detected in OVA-treated rats before PM2.5 exposure. Specifically, there were positive or negative correlations between the levels of Th2-associated cytokines (IL-4, IL-5, and IL-13) and six metabolites in the OVA-treated group before PM2.5 exposure, whereas the levels of IL-4 and IL-5 were negatively correlated with five metabolites in the OVA-treated group after PM2.5 exposure. Our findings suggest that PM2.5 exposure could influence the susceptibility of allergic asthma in response to allergens in elderly rats, potentially through changes in plasma metabolites.

N6-methyladenosine in inflammatory diseases: Important actors and regulatory targets

N6-methyladenosine (m6A) is one of the most prevalent epigenetic modifications in eukaryotic cells. It regulates RNA function and stability by modifying RNA methylation through writers, erasers, and readers. As a result, m6A plays a critical role in a wide range of biological processes. Inflammation is a common and fundamental pathological process. Numerous studies have investigated the role of m6A modifications in inflammatory diseases. This review highlights the mechanisms by which m6A contributes to inflammation, focusing on pathogen-induced infectious diseases, autoimmune disorders, allergic conditions, and metabolic disorder-related inflammatory diseases.

Biologic therapies targeting type 2 cytokines are effective at improving asthma symptoms and control-a systematic review and meta-analysis

Background

Allergic asthma is a highly prevalent chronic inflammatory disease driven by aeroallergen exposure. In severe asthma, the current standard of care does not fully control disease symptoms, indicating an unmet clinical need. Biologic therapies targeting cytokines IL-4, IL-5, and IL-13 have been shown to provide benefits to asthmatic patients over currently existing asthma treatments.

Objective

We sought to review the effects of recently developed biologic therapies for asthma treatment.

Methods

In this meta-analysis, the impact of IL-5 and IL-4/IL-13 biologic inhibitors was critically appraised considering overall lung function, symptom control, and oral corticosteroid use in asthmatic patients. Trials were identified using PubMed, Web of Science, Scopus, and clinicaltrials.gov. Clinical trials assessing severe asthmatic participants older than 12 years were included.

Results

The meta-analysis included 6600 participants from 14 trials published in 2013 to 2020. For IL-5 inhibitors, improvements in FEV1 (mean difference [MD], 0.11; 95% CI, 0.11 to 0.12), Asthma Control Questionnaire scores (MD, -0.4; 95% CI, -0.41 to -0.38), annual exacerbation rates (MD, -0.46; 95% CI, -0.48 to -0.45), and oral corticosteroid use (MD, -50; 95% CI, -52.58 to -47.42) favored biologic treatment. Significant improvements in FEV1 (MD, 0.11; 95% CI, 0.10 to 0.11), Asthma Control Questionnaire scores (MD, -0.20; 95% CI, -0.22 to -0.18), and annual exacerbation rates (MD, -0.15; 95% CI, -0.16 to -0.14) were also seen with anti-IL-4/IL-13 biologic therapies. However, anti-IL-4/IL-13 inhibitors were associated with more adverse events than placebo (MD, 1.13; 95% CI, 0.97 to 1.3).

Conclusions

Biologic inhibitors targeting TH2 cytokines are beneficial for improving overall asthma control.

Increased Risk of Rheumatoid Arthritis in Patients With Asthma: A Genetic Association Study Using Two-Sample Mendelian Randomization Analysis

OBJECTIVE

Observational studies have explored the association between asthma and some types of arthritis, including rheumatoid arthritis and osteoarthritis, but the results are largely contradictory. We aimed to investigate the causal effects of asthma on arthritis, including osteoarthritis, rheumatoid arthritis, gout, and ankylosing spondylitis.

METHODS

Two-sample Mendelian randomization (MR) analysis was used to investigate the causal effects of asthma on each arthritis. The genetic instruments for asthma were obtained from a large genome-wide association study of asthma. The inverse-variance weighted (IVW) method was used as the main analysis of MR. Bonferroni-adjusted P value threshold was used to account for multiple comparisons.

RESULTS

MR-IVW analysis suggested that adult-onset asthma (AOA) was associated with increased risk of rheumatoid arthritis. The odds ratio for rheumatoid arthritis associated with AOA and childhood-onset asthma (COA) were 1.018 (95% confidence interval [95% CI], 1.011-1.025; P < 0.001) and 1.006 (95% CI 1.001-1.012; P = 0.046), respectively. For osteoarthritis, gout, or ankylosing spondylitis, all the MR analyses showed no significant causal effects of AOA or COA on them. We also performed a reverse MR analysis to explore the causal effects of rheumatoid on all asthma, allergic asthma, or nonallergic asthma and found no significant causal effects on them.

CONCLUSION

Genetically predicted AOA predisposes patients to an increased risk of rheumatoid arthritis but has no causal effects on osteoarthritis, gout, and ankylosing spondylitis. The result of COA on rheumatoid arthritis is suggestive of potential causal relationship but needs to be confirmed in further studies.

A comparison of the impact of anti-IL5/5r therapies in allergic versus non-allergic patients with severe eosinophilic asthma in a real-life setting

OBJECTIVE

This study aimed to compare the clinical characteristics and treatment outcomes of allergic patients (AP) and non-allergic patients (NAP) with severe eosinophilic asthma (SEA) treated with anti-IL5/IL5R biologic agents (mepolizumab, benralizumab, or reslizumab) over one year. Sub-analyses assessed treatment response variations between AP and NAP based on the biological used and compared outcomes among AP with and without fungal allergy.

METHODS

Observational retrospective analysis. Clinical characteristics, laboratory findings, pulmonary function tests, Asthma Control Test (ACT) scores, oral corticosteroid (OCS) usage, and exacerbation frequency were assessed at the initiation of biological treatment and after one year.

RESULTS

Sixty-five patients with SEA were included, 41 AP and 24 NAP. 55.4% were treated with mepolizumab, 33.8% with benralizumab, and 10.8% with reslizumab. Before anti-IL5/5R treatment, AP had worse baseline outcomes but there were no differences in pulmonary function. Mean annual exacerbation rate and percentage of patients requiring OCS and dose of prednisone were higher in AP than NAP. AP had significantly higher total IgE values. After one year of treatment, more AP discontinued OCS than NAP (p = 0.025). Both experienced a significant reduction in exacerbation frequency (p = 0.001) and improved respiratory function. 70.7% of AP and 60% of NAP improved ACT ≥3 points. There was no significant difference between AP and NAP using mepolizumab (p = 0.145) or benralizumab (p = 0.174) in reducing OCS.

CONCLUSIONS

Anti-IL5/IL5R reduced the need for OCS and improved asthma control, regardless of allergic status. Fungal allergy led to lower ACT scores and higher exacerbations than other allergens; both groups improved with anti-IL5/ILR.

IL-33 released during challenge phase regulates allergic asthma in an age-dependent way

Epithelial-derived cytokines, especially type 2 alarmins (TSLP, IL-25, and IL-33), have emerged as critical mediators of type 2 inflammation. IL-33 attracts more interest for its strong association with allergic asthma, especially in childhood asthma. However, the age-dependent role of IL-33 to the development of allergic asthma remains elusive. Here, using OVA-induced allergic asthma model in neonatal and adult mice, we report that IL-33 is the most important alarmin in neonatal lung both at steady state or inflammation. The deficiency of IL-33/ST2 abrogated the development of allergic asthma only in neonates, whereas in adults the effect was limited. Interestingly, the deficiency of IL-33/ST2 equally dampened the ILC2 responses in both neonatal and adult models. However, the effect of IL-33/ST2 deficiency on Th2 responses is age-dependent, which is only blocked in neonates. Furthermore, IL-33/ST2 signaling is dispensable for OVA sensitization. Following OVA challenge in adults, the deficiency of IL-33/ST2 results in compensational more TSLP, which in turn recruits and activates lung DCs and boosts Th2 responses. The enriched γδ T17 cells in IL-33/ST2 deficient neonatal lung suppress the expression of type 2 alarmins, CCL20 and GM-CSF via IL-17A, thus might confer the inhibition of allergic asthma. Finally, on the basis of IL-33 deficiency, the additive protective effects of TSLP blocking is much more pronounced than IL-25 blocking in adults. Our studies demonstrate that the role of IL-33 for ILC2 and Th2 responses varies among ages in OVA models and indicate that the factor of age should be considered for intervention of asthma.

Molecular allergy diagnosis enabling personalized medicine

Allergic patients are characterized by complex and patient-specific IgE sensitization profiles to various allergens, which are accompanied by different phenotypes of allergic disease. Molecular allergy diagnosis establishes the patient's IgE reactivity profile at a molecular allergen level and has moved allergology into the era of precision medicine. Molecular allergology started in the late 1980s with the isolation of the first allergen-encoding DNA sequences. Already in 2002, the first allergen microarrays were developed for the assessment of complex IgE sensitization patterns. Recombinant allergens are used for a precise definition of personal IgE reactivity profiles, identification of genuine IgE sensitization to allergen sources for refined prescription of allergen-specific immunotherapy and allergen avoidance diagnosis of co- versus cross-sensitization, epidemiologic studies, and prediction of symptoms, phenotypes, and development of allergic disease. For example, molecular IgE sensitization patterns associated with more severe respiratory allergies, severe food allergy, and allergy to honeybee or vespids are already established. The implementation of molecular allergy diagnosis into daily clinical practice requires continuous medical education and training doctors in molecular allergy diagnosis, and may be facilitated by clinical decision support systems such as diagnostic algorithms that may take advantage of artificial intelligence.

Detection of egg white allergy in children by specific IgE microarray chemiluminescence immunoassay

BACKGROUND

Allergen testing has emerged as a pivotal component in prevention and treatment strategies for allergic diseases among children and the utilization of specific IgE (sIgE) through a fully automated chemiluminescent microarray immunoassay (CLMIA) has emerged as a promising trend in the simultaneous detection of multiple allergenic components of children.

METHODS

The accuracy and reliability of CLMIA were verified using children's serum samples that concentrated on allergens. the allergens. The clinical diagnostic practicability of CLMIA was assessed through comprehensive evaluations including measurements of the limit of detection (LOD), intra-batch, and inter-batch precision, linearity analysis, the cross-contamination rate, and the concordance rate with the Phadia system.

RESULTS

After the optimization process of CLMIA, the LODs for allergens were calculated to be below 0.01 kU/L, demonstrating the high sensitivity of CLMIA. All components exhibited good linearity within the range of 0.1-100.0 kU/L and the coefficient of determinations (R2 > 0.99). The data of intra-batch precision (<10 %) and inter-batch data (<15 %) illustrated the high reproducibility of CLMIA. The cross-contamination rates for allergens (<0.5 %) showed the high accuracy of CLMIA without interfering. The positive concordance rate between CLMIA and the Phadia system exceeds 90 % with a good negative concordance rate (>85 %) and the Kappa coefficients (>0.8), suggesting the close alignment of CLMIA and the Phadia system and showing the satisfactory clinical potential of CLMIA in children's allergy disease.

CONCLUSIONS

The application of CLMIA has been promising in allergen testing, especially for detecting multiple allergenic components in children.

Evaluating the Anti-inflammatory Potential of JN-KI3: The Therapeutic Role of PI3Kγ-Selective Inhibitors in Asthma Treatment

Asthma is a chronic airway inflammatory disease of the airways characterized by the involvement of numerous inflammatory cells and factors. Therefore, targeting airway inflammation is one of the crucial strategies for developing novel drugs in the treatment of asthma. Phosphoinositide 3-kinase gamma (PI3Kγ) has been demonstrated to have a significant impact on inflammation and immune responses, thus emerging as a promising therapeutic target for airway inflammatory disease, including asthma. There are few studies reporting on the therapeutic effects of PI3Kγ-selective inhibitors in asthma disease. In this study, we investigated the anti-inflammatory and therapeutic effects of PI3Kγ-selective inhibitor JN-KI3 for treating asthma by utilizing both in vivo and in vitro approaches, thereby proving that PI3Kγ-selective inhibitors could be valuable in the treatment of asthma. In RAW264.7 macrophages, JN-KI3 effectively suppressed C5a-induced Akt phosphorylation in a concentration-dependent manner, with no discernible toxicity observed in RAW264.7 cells. Furthermore, JN-KI3 can inhibit the PI3K/Akt signaling pathway in lipopolysaccharide-induced RAW264.7 cells, leading to the suppression of transcription and expression of the classical inflammatory cytokines in a concentration-dependent manner. Finally, an ovalbumin-induced murine asthma model was constructed to evaluate the initial therapeutic effect of JN-KI3 for treating asthma. Oral administration of JN-KI3 inhibited the infiltration of inflammatory cells and the expression of T-helper type 2 cytokines in bronchoalveolar lavage fluid, which was associated with the suppression of the PI3K signaling pathway. Lung tissue and immunohistochemical studies demonstrated that JN-KI3 inhibited the accumulation of inflammatory cells around the bronchus and blood vessels, as well as the secretion of mucus and excessive deposition of collagen around the airway. In addition, it reduced the infiltration of white blood cells into the lungs. In summary, JN-KI3 shows promise as a candidate for the treatment of asthma. Our study also suggests that the inhibitory effects of PI3Kγ on inflammation could offer an additional therapeutic strategy for pulmonary inflammatory diseases.

Natural Products for the Management of Asthma and COPD

Chronic airway inflammatory diseases like asthma, chronic obstructive pulmonary disease (COPD), and their associated exacerbations cause significant socioeconomic burden. There are still major obstacles to effective therapy for controlling severe asthma and COPD progression. Advances in understanding the pathogenesis of the two diseases at the cellular and molecular levels are essential for the development of novel therapies. In recent years, significant efforts have been made to identify natural products as potential drug leads for treatment of human diseases and to investigate their efficacy, safety, and underlying mechanisms of action. Many major active components from various natural products have been extracted, isolated, and evaluated for their pharmacological efficacy and safety. For the treatment of asthma and COPD, many promising natural products have been discovered and extensively investigated. In this chapter, we will review a range of natural compounds from different chemical classes, including terpenes, polyphenols, alkaloids, fatty acids, polyketides, and vitamin E, that have been demonstrated effective against asthma and/or COPD and their exacerbations in preclinical models and clinical trials. We will also elaborate in detail their underlying mechanisms of action unraveled by these studies and discuss new opportunities and potential challenges for these natural products in managing asthma and COPD.

Recent advances in research on common targets of neurological and sex hormonal influences on asthma

BACKGROUND

Asthma is currently one of the most common of respiratory diseases, severely affecting the lives of patients. With the in-depth study of the role of the nervous system and sex hormones on the development of asthma, it has been found that the nervous system and sex hormones are related to each other in the pathway of asthma.

OBJECTIVE

To investigate the effects of sex hormones and the nervous system on the development of asthma.

METHODS

In this review, we searched for a large number of relevant literature to elucidate the unique mechanisms of sex hormones and the nervous system on asthma development, and summarized several common targets in the pathways of sex hormones and the nervous system on asthma.

CONCLUSION

We summarize several common important targets in the pathways of action of sex hormones and the nervous system in asthma, provide new directions and ideas for asthma treatment, and discuss current therapeutic limitations and future possibilities. Finally, the article predicts future applications of several important targets in asthma therapy.

The Role of Flavonoids from Aurantii Fructus Immaturus in the Alleviation of Allergic Asthma: Theoretical and Practical Insights

Flavonoids derived from plants in the citrus family can have an alleviating effect on allergic asthma. The aim of this study was to provide insights into the mechanisms by which these compounds exert their effects on allergic asthma by combining theoretical and practical approaches. Aurantii Fructus Immaturus flavonoids (AFIFs) were obtained by solvent extraction and were determined by high performance liquid chromatography (HPLC). In vivo and in vitro experiments combined with network pharmacology, Mendelian randomization (MR) analysis and the AutoDock method were applied to study the mechanism of their effects. The main AFIFs were found to be hesperidin (13.21 mg/g), neohesperidin (287.26 mg/g), naringin (322.56 mg/g), and narirutin (19.35 mg/g). Based on the network pharmacology and MR analysis results, five targets Caspase 3 (CASP3), CyclinD1 (CCND1), Intercellular adhesion molecule (ICAM), erb-b2 receptor tyrosine kinase 2 (ERBB2), and rubisco accumulation factor 1 (RAF1) were selected, and the interactions between the AFIFs and the targets were studied using AutoDock Vina. The results indicated that glycosidic bonds play an important role in the interactions between AFIFs and both ERBB2 and RAF1.

The Presence and Pathogenic Roles of M(IL-33 + IL-2) Macrophages in Allergic Airway Inflammation

BACKGROUND

Macrophages, one of the most abundant immune cells in the lung, have drawn great attention in allergic asthma. Currently, most studies emphasize alternative activated (M2) polarization bias. However, macrophage function in allergic asthma is still controversial. Interleukin (IL)-9 contributes to the development and pathogenesis of allergic airway inflammation. We sought to investigate the IL-9-producing macrophage and its role in allergic asthma.

METHODS

The model of ovalbumin (OVA)-induced allergic airway inflammation was employed to evaluate IL-9 production in macrophages of lung tissues. We used 22 cytokines or stimuli to screen for IL-9-producing mouse macrophage subset in vitro. Real-time PCR, flow cytometry, ELISA, and RNA-seq to explore the subset. Conditional IL-33 receptor knockout (Lyz-ST2KO) mice and cellular adoptive transfer experiment were used to characterize the potential roles of M(IL-33 + IL-2) in allergic asthma.

RESULTS

We identified a unique pathogenic IL-9-producing macrophage in OVA-induced allergic airway inflammation. We found that only IL-33 significantly induced IL-9 production in mouse macrophages, and IL-2 collaborated with IL-33 to promote IL-9 production, referred to as M(IL-33 + IL-2). Importantly, human monocyte-derived macrophages produced IL-9 after IL-33 and IL-2 stimulation. Using Lyz-ST2KO mice and adoptive transfer of M(IL-33 + IL-2), we found that M(IL-33 + IL-2) significantly promoted pathogenesis in OVA-induced allergic airway inflammation. M(IL-33 + IL-2) has a distinctive gene expression profile with high expression of IL-9, IL-5, and IL-13 and its polarization is dependent on JAK2-STAT3-IRF1 pathway.

CONCLUSIONS

The identification of M(IL-33 + IL-2) subset extends the diversity and heterogeneity of macrophage subsets and may offer novel therapeutic strategies for the treatment of allergic inflammation.

Identification of severe acute pediatric asthma phenotypes using unsupervised machine learning

RATIONALE

More targeted management of severe acute pediatric asthma could improve clinical outcomes.

OBJECTIVES

To identify distinct clinical phenotypes of severe acute pediatric asthma using variables obtained in the first 12 h of hospitalization.

METHODS

We conducted a retrospective cohort study in a quaternary care children's hospital from 2014 to 2022. Encounters for children ages 2-18 years admitted to the hospital for asthma were included. We used consensus k means clustering with patient demographics, vital signs, diagnostics, and laboratory data obtained in the first 12 h of hospitalization.

MEASUREMENTS AND MAIN RESULTS

The study population included 683 encounters divided into derivation (80%) and validation (20%) sets, and two distinct clusters were identified. Compared to Cluster 1 in the derivation set, Cluster 2 encounters (177 [32%]) were older (11 years [8; 14] vs. 5 years [3; 8]; p < .01) and more commonly males (63% vs. 53%; p = .03) of Black race (51% vs. 40%; p = .03) with non-Hispanic ethnicity (96% vs. 84%; p < .01). Cluster 2 encounters had smaller improvements in vital signs at 12-h including percent change in heart rate (-1.7 [-11.7; 12.7] vs. -7.8 [-18.5; 1.7]; p < .01), and respiratory rate (0.0 [-20.0; 22.2] vs. -11.4 [-27.3; 9.0]; p < .01). Encounters in Cluster 2 had lower percentages of neutrophils (70.0 [55.0; 83.0] vs. 85.0 [77.0; 90.0]; p < .01) and higher percentages of lymphocytes (17.0 [8.0; 32.0] vs. 9.0 [5.3; 14.0]; p < .01). Cluster 2 encounters had higher rates of invasive mechanical ventilation (23% vs. 5%; p < .01), longer hospital length of stay (4.5 [2.6; 8.8] vs. 2.9 [2.0; 4.3]; p < .01), and a higher mortality rate (7.3% vs. 0.0%; p < .01). The predicted cluster assignments in the validation set shared the same ratio (~2:1), and many of the same characteristics.

CONCLUSIONS

We identified two clinical phenotypes of severe acute pediatric asthma which exhibited distinct clinical features and outcomes.

Silencing TRIM8 alleviates allergic asthma and suppressing Th2 differentiation through inhibiting NF-κB/NLRP3 signaling pathway

BACKGROUND AND AIM

Allergic asthma is a primary type of asthma and characterized by T helper 2 (Th2) cells -mediated inflammation. Tripartite motif containing 8 (TRIM8) protein is involved in immunoreaction and inflammatory response in many diseases. However, its role in allergic asthma remains unclear. Medical databank showed that TRIM8 was increased in lung of ovalbumin (OVA)-challenged mice. This study aimed to elucidate the effects of TRIM8 on allergic asthma and Th2 development.

METHODS

Asthma were induced by OVA challenge in mice, and the adenovirus vector loaded with TRIM8 knockdown sequence was delivered into asthma mice by nasal inhalation. The percentage of Th2 cells in lung was assessed by flow cytometric analysis, and the contents of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) were assessed with ELISA. In vitro Th2 induction was performed in CD4+ cells from mouse spleen, the expression of Th2 molecules (IL-4, IL-5 and GATA binding protein 3 (GATA3)) were measured by real-time PCR. In addition, the nuclear factor-kappa B (NF-κB)/nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) signaling was determined.

RESULTS

TRIM8 was highly expressed in the lung tissues of asthmatic mice and Th2-induced CD4+ cells. OVA challenge-induced Th2 development and Th2 cytokine secretion were restrained by silencing of TRIM8 in vivo. Similarly, the Th2 differentiation in vitro was also suppressed by TRIM8 knockdown. TRIM8 inhibited the NF-κB/NLRP3 activity by blocking transforming growth factor-beta-activated kinase 1 (TAK1), and the effects of TRIM8 were abrogated by overexpression of NLRP3.

CONCLUSIONS

Silencing TRIM8 relieved the asthmatic injury in mice and excessive Th2 development via inhibiting the NF-κB/NLRP3 pathway. It is indicated that TRIM8 may contribute to the airway inflammation in allergic asthma via activating the NF-κB/NLRP3 signaling pathway. The current study provided a novel potential target for allergic asthma treatment.

Experimental and proteomics evidence revealed the protective mechanisms of Shemazhichuan Liquid in attenuating neutrophilic asthma

BACKGROUND

Neutrophilic asthma (NA) is one of the most important phenotypes of non-Th2 asthma and is often insensitive to glucocorticoid therapy, making current treatment difficult. Shemazhichuan Liquid (SMZCL), a Chinese medicine compound preparation, has unique advantages in the treatment of asthma. However, the underlying mechanisms of SMZCL in treating NA are not fully understood.

PURPOSE

The efficacy and underlying mechanisms of SMZCL on NA were investigated by TMT-labeled quantitative proteomics analysis and in vivo and in vitro experiments.

METHODS

NA mouse model was constructed by OVA/CFA sensitization followed by a 10-day challenge with 5 % OVA. Lung histopathology, leukocyte counts and cell sorting counts, inflammatory cytokines levels, as well as expression of autophagy markers were then assessed. The specific pathways and proteins of SMZCL for treating NA were further illustrated through TMT-based quantitative proteomics. In addition, RAW264.7 cells were induced by LPS to further explore the mechanism of the main active ingredient of SMZCL on autophagy pathway.

RESULTS

In vivo, SMZCL contributed to attenuating airway inflammation and collagen disposition, markedly reduced the number of leukocytes, especially neutrophils in bronchoalveolar lavage fluid (BALF), as well as decreased IgE and inflammatory cytokine levels (TNF-α, IL-1β, IL-6 and IL-8) in BALF and serum. Besides, SMZCL elevated the levels of LC3 and ATG5 while inhibiting the expression of p62 and mTOR. Mzb1 and Rab3ip were identified as the critical overlapping DEPs whose expression was inhibited by SMZCL and rapamycin. KEGG enrichment analysis showed that necroptosis process was a key pathway for SMZCL to treat NA airway inflammation. IHC and WB results confirmed that SMZCL and rapamycin inhibited the phosphorylation of RIPK1, PIPK3 and MLKL. In vitro, ATG5 and LC3 proteins were obviously increased while p-mTOR expression was inhibited after amygdalin treatment.

CONCLUSION

SMZCL attenuated airway inflammation in NA mainly through inhibition of the mTOR pathway, along with inhibition of the necroptosis pathway regulated by the RIPK1/RIPK3/MLKL axis and inhibition of Mzb1 and Rab3ip expression.

Unraveling heterogeneity and treatment of asthma through integrating multi-omics data

Asthma has become one of the most serious chronic respiratory diseases threatening people's lives worldwide. The pathogenesis of asthma is complex and driven by numerous cells and their interactions, which contribute to its genetic and phenotypic heterogeneity. The clinical characteristic is insufficient for the precision of patient classification and therapies; thus, a combination of the functional or pathophysiological mechanism and clinical phenotype proposes a new concept called "asthma endophenotype" representing various patient subtypes defined by distinct pathophysiological mechanisms. High-throughput omics approaches including genomics, epigenomics, transcriptomics, proteomics, metabolomics and microbiome enable us to investigate the pathogenetic heterogeneity of diverse endophenotypes and the underlying mechanisms from different angles. In this review, we provide a comprehensive overview of the roles of diverse cell types in the pathophysiology and heterogeneity of asthma and present a current perspective on their contribution into the bidirectional interaction between airway inflammation and airway remodeling. We next discussed how integrated analysis of multi-omics data via machine learning can systematically characterize the molecular and biological profiles of genetic heterogeneity of asthma phenotype. The current application of multi-omics approaches on patient stratification and therapies will be described. Integrating multi-omics and clinical data will provide more insights into the key pathogenic mechanism in asthma heterogeneity and reshape the strategies for asthma management and treatment.

Positioning tezepelumab for patients with severe asthma: from evidence to unmet needs

Several endotypes of severe asthma with predominantly type 2 inflammation can be distinguished by the immune pathways driving the inflammatory processes. However, in the absence of type 2 inflammation, asthma is less clearly defined and is generally associated with poor responses to conventional anti-asthmatic therapies. Studies have shown that disruption of the epithelial barrier triggers inflammatory responses and increases epithelial permeability. A key aspect of this process is that epithelial cells release alarmin cytokines, including interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP), in response to allergens and infections. Among these cytokines, TSLP has been identified as a potential therapeutic target for severe asthma, leading to the development of a new biologic, tezepelumab (TZP). By blocking TSLP, TZP may produce wide-ranging effects. Based on positive clinical trial results, TZP appears to offer a promising, safe, and effective treatment approach. This narrative review examines the evidence for treating severe asthma with TZP, analyses clinical trial findings, and provides clinicians with practical insights into identifying patients who may respond best to this novel biologic therapy.

Dupilumab 200 mg was efficacious in children (6-11 years) with moderate-to-severe asthma for up to 2 years: EXCURSION open-label extension study

BACKGROUND

The phase 3 VOYAGE (NCT02948959) and open-label extension EXCURSION (NCT03560466) studies evaluated dupilumab in children (6-11 years) with uncontrolled moderate-to-severe asthma. This post hoc analysis assessed the efficacy and safety of add-on dupilumab 200 mg every 2 weeks (q2w), the largest dose cohort in both studies, in children from VOYAGE who participated in EXCURSION.

METHODS

Annualized rate of severe asthma exacerbations (AERs), change in prebronchodilator percent predicted forced expiratory volume in 1 s (ppFEV1), and treatment-emergent adverse events were assessed in children with moderate-to-severe asthma who received dupilumab 200 mg q2w in VOYAGE and EXCURSION (dupilumab/dupilumab arm) and those who received placebo in VOYAGE and dupilumab 200 mg q2w in EXCURSION (placebo/dupilumab arm). These endpoints were also assessed in children with moderate-to-severe type 2 asthma (defined as blood eosinophil count ≥150 cells/µL or FeNO ≥20 ppb at the parent study baseline [PSBL]).

RESULTS

In the overall population, dupilumab reduced AER and improved prebronchodilator ppFEV1 in the dupilumab/dupilumab arm (n = 158) for up to 2 years. Children receiving placebo/dupilumab (n = 85) showed similar reductions after initiation of dupilumab 200 mg q2w in EXCURSION. Similar results were observed for children with type 2 asthma at PSBL. The safety profile was consistent with the known safety profile of dupilumab.

CONCLUSION

In children (6-11 years) with uncontrolled moderate-to-severe type 2 asthma, dupilumab 200 mg reduced exacerbation rates and improved lung function for up to 2 years and showed safety consistent with the known dupilumab safety profile.

Depression of CaV1.2 activation and expression in mast cells ameliorates allergic inflammation diseases

Allergic inflammation is closely related to the activation of mast cells (MCs), which is regulated by its intracellular Ca2+ level, but the intake and effects of the intracellular Ca2+ remain unclear. The Ca2+ influx is controlled by members of Ca2+ channels, among which calcium voltage-gated channel subunit alpha1 C (CaV1.2) is the most robust. This study aimed to reveal the role and underlying mechanism of MC CaV1.2 in allergic inflammation. We found that CaV1.2 participated in MC activation and allergic inflammation. Nimodipine (Nim), as a strong CaV1.2-specific antagonist, ameliorated allergic inflammation in mice. Further, CaV1.2 activation in MC was triggered by phosphatizing at its Ser1928 through protein kinase C (PKC), which calcium/calmodulin-dependent protein kinase II (CaMKII) catalyzed. Overexpression or knockdown of MC CaV1.2 influenced MC activation. Importantly, CaV1.2 expression in MC had detrimental effects, while its deficiency ameliorated allergic pulmonary inflammation. Results provide novel insights into CaV1.2 function and a potential drug target for controlling allergic inflammation.

Release of sputum neutrophil granules is associated with pulmonary function and disease severity in childhood asthma

BACKGROUND

Myeloperoxidase (MPO) and human neutrophil lipocalin or neutrophil gelatinase-associated lipocalin (HNL/NGAL) are stored in neutrophil granulocytes and secreted upon activation of the cells. They have been proposed to reflect the degree of inflammation in the airways. However, their role as potential markers of disease severity in childhood asthma remains unknown. This study investigated the relationship between the expression of MPO and HNL/NGAL and childhood asthma.

METHODS

A total of 83 pediatric patients with asthma and 59 controls were enrolled. Using enzyme-linked immunosorbent assays, the human MPO and HNL/NGAL levels were measured in sputum supernatants. Assessments including spirometry, methacholine challenge test, and atopy test were conducted.

RESULTS

No difference in sputum neutrophil counts was observed between pediatric patients with asthma and controls. However, sputum MPO and HNL/NGAL levels were significantly higher in patients with asthma than in controls (p = 0.021 and p < 0.001, respectively), especially in patients with moderate-to-severe persistent asthma. In patients with asthma, sputum MPO and HNL/NGAL levels showed a positive correlation with sputum neutrophil counts (MPO, r = 0.433, p < 0.001; HNL/NGAL, r = 0.584, p < 0.001) and with each other (r = 0.628, p < 0.001). Moreover, sputum HNL/NGAL level demonstrated better ability to accurately reflect current pulmonary function, airway inflammation, and limitations than MPO level in this study.

CONCLUSIONS

Sputum MPO and HNL/NGAL levels, which reflect neutrophil activation in airways, were increased in pediatric patients with asthma. Moreover, sputum MPO and HNL/NGAL may serve as appropriate assessment indicators of asthma severity in pediatric patients.

Expert opinion on diagnosis and management of Severe Asthma in low and middle income countries (LMIC) with focus on India

OBJECTIVE

In this document, 9 Indian experts have evaluated the factors specific to LMICs when it came to Severe Asthma (SA) diagnosis, evaluation, biologic selection, non-biologic treatment options, and follow-up.

DATA SOURCES

A search was performed using 50 keywords, focusing on the Indian/LMICs perspective, in PubMed, Cochrane Library, and Google Scholar. The key areas of the search were focused on diagnosis, phenoendotyping, non-biological therapies, selecting a biologic, assessment of treatment response, and management of exacerbation.

STUDY SELECTIONS

The initial search revealed 1826 articles, from these case reports, observational studies, cohort studies, non-English language papers, etc., were excluded and we short-listed 20 articles for each area. Five relevant articles were selected by the experts for review.

RESULTS

In LMICs, SA patients may be referred to the specialist for evaluation a little late for Phenoendotyping of SA. While biologic therapy is now a standard of care, pulmonologists in LMICs may not have access to all the investigations to phenoendotype SA patients like fractional exhaled nitric oxide (FeNO), skin prick test (SPT), etc., but phenotyping of SA patients can also be done with simple blood investigations, eosinophil count and serum immunoglobulin E (IgE). Choosing a biologic in the overlapping phenotype of SA and ACO patients is also a challenge in the LMICs.

CONCLUSIONS

Given the limitations of LMIC, it is important to select the right patient and explain the potential benefits of biological therapy. Non-biologic add-on therapies can be attempted in a resource-limited setting where biological therapy is not available/feasible for patients.

Deciphering cuproptosis-related signatures in pediatric allergic asthma using integrated scRNA-seq and bulk RNA-seq analysis

OBJECTIVE

Allergic asthma (AA) is common in children. Excess copper is observed in AA patients. It is currently unclear whether copper imbalance can cause cuproptosis in pediatric AA.

METHODS

The datasets about pediatric AA (GSE40732 and GSE40888) were obtained from Gene Expression Omnibus (GEO) database. The expression of cuproptosis-related genes (CRGs) and immune cell infiltration in pediatric AA samples were analyzed. Single-cell RNA sequencing (scRNA-seq) data (GSE193816) were used to evaluate the expression patterns of CRGs in AA. The identification of differentially expressed genes within clusters was conducted using weighted gene co-expression network analysis. Subsequently, disease progression and cuproptosis-related models were screened using random forest (RF), support vector machine (SVM), extreme gradient boosting (XGBoost), and general linear model (GLM) algorithms.

RESULTS

Four CRGs were notably increased in pediatric AA samples. CD4+ T cells, macrophages and mast cells exhibited a lower cuproptosis score in AA samples, indicating that these immune cells may be closely associated with cuproptosis in AA development. Co-expression network of CRGs in AA was constructed. AA samples were divided into two cuprotosis clusters. Following construction of four machine-learning models, SVM model exhibited the highest efficacy of prediction in the testing set (AUC = 0.952). SVM model containing five important variables can be used for prediction of AA.

CONCLUSION

This work provided a machine learning model containing five important variables, which may have good diagnostic efficiency for pediatric AA.

Specific microRNA Profile Associated with Inflammation and Lipid Metabolism for Stratifying Allergic Asthma Severity

The mechanisms underlying severe allergic asthma are complex and unknown, meaning it is a challenge to provide the most appropriate treatment. This study aimed to identify novel biomarkers for stratifying allergic asthmatic patients according to severity, and to uncover the biological mechanisms that lead to the development of the severe uncontrolled phenotype. By using miRNA PCR panels, we analyzed the expression of 752 miRNAs in serum samples from control subjects (n = 15) and mild (n = 11) and severe uncontrolled (n = 10) allergic asthmatic patients. We identified 40 differentially expressed miRNAs between severe uncontrolled and mild allergic asthmatic patients. Functional enrichment analysis revealed signatures related to inflammation, angiogenesis, lipid metabolism and mRNA regulation. A random forest classifier trained with DE miRNAs achieved a high accuracy of 97% for severe uncontrolled patient stratification. Validation of the identified biomarkers was performed on a subset of allergic asthmatic patients from the CAMP cohort at Brigham and Women's Hospital, Harvard Medical School. Four of these miRNAs (hsa-miR-99b-5p, hsa-miR-451a, hsa-miR-326 and hsa-miR-505-3p) were validated, pointing towards their potential as biomarkers for stratifying allergic asthmatic patients by severity and providing insights into severe uncontrolled asthma molecular pathways.

The Effect of a TLR3 Agonist on Airway Allergic Inflammation and Viral Infection in Immunoproteasome-Deficient Mice

Allergic asthma is characterized by increased type 2 inflammation, including eosinophils. Subjects with allergic asthma have recurrent symptoms due to their constant exposure to environmental allergens, such as house dust mite (HDM), which can be further exacerbated by respiratory infections like rhinovirus. The immunoproteasome (IP) is a proteolytic machinery that is induced by inflammatory mediators during virus infection, but the role of the IP in airway allergic inflammation during rhinovirus infection remains unknown. Wild-type (WT) and IP knockout (KO) mice were challenged with HDM. At 48 h after the last HDM challenge, mice were infected with rhinovirus 1B (RV-A1B) for 24 h. After HDM and RV-A1B treatment, IP KO (vs. WT) mice had significantly more lung eosinophils and neutrophils, as well as a significantly higher viral load, but less IFN-beta expression, compared to WT mice. A TLR3 agonist polyinosinic-polycytidylic acid (Poly I:C) treatment after RV-A1B infection in HDM-challenged IP KO mice significantly increased IFN-beta expression and reduced viral load, with a minimal effect on the number of inflammatory cells. Our data suggest that immunoproteasome is an important mechanism functioning to prevent excessive inflammation and viral infection in allergen-exposed mice, and that Poly I:C could be therapeutically effective in enhancing the antiviral response and lessening the viral burden in lungs with IP deficiency.

Causal Effects of Asthma on Upper Airway Diseases and Allergic Diseases: A Two-Sample Mendelian Randomization

INTRODUCTION

Asthma is associated with upper airway diseases and allergic diseases; however, the causal effects need to be investigated further. Thus, we performed this two-sample Mendelian randomization (MR) analysis to explore and measure the causal effects of asthma on allergic rhinitis (AR), vasomotor rhinitis (VMR), allergic conjunctivitis (AC), atopic dermatitis (AD), and allergic urticaria (AU).

METHODS

The data for asthma, AR, VMR, AC, AD, and AU were obtained from large-scale genome-wide association studies summarized recently. We defined single-nucleotide polymorphisms satisfying the MR assumptions as instrumental variables. Inverse-variance weighted (IVW) approach under random-effects was applied as the dominant method for causal estimation. The weighted median approach, MR-Egger regression analysis, MR pleiotropy residual sum and outlier test, and leave-one-out sensitivity analysis were performed as sensitivity analysis. Horizontal pleiotropy was measured using MR-Egger regression analysis. Significant causal effects were attempted for replication and meta-analysis.

RESULTS

We revealed that asthma had causal effects on AR (IVW, odds ratio [OR] = 1.93; 95% confidence interval [CI], 1.74-2.14; p < 0.001), VMR (IVW, OR = 1.40; 95% CI, 1.15-1.71; p < 0.001), AC (IVW, OR = 1.65; 95% CI, 1.49-1.82; p < 0.001), and AD (IVW, OR = 2.13; 95% CI, 1.82-2.49; p < 0.001). No causal effect of asthma on AU was observed. Sensitivity analysis further assured the robustness of these results. The evaluation of the replication stage and meta-analysis further confirmed the causal effect of asthma on AR (IVW OR = 1.81, 95% CI 1.62-2.02, p < 0.001), AC (IVW OR = 1.44, 95% CI 1.11-1.87, p < 0.001), and AD (IVW OR = 1.85, 95% CI 1.42-2.41, p < 0.001).

CONCLUSIONS

We revealed and quantified the causal effects of asthma on AR, VMR, AC, and AD. These findings can provide powerful causal evidence of asthma on upper airway diseases and allergic diseases, suggesting that the treatment of asthma should be a preventive and therapeutic strategy for AR, VMR, AC, and AD.

Fagopyrum Dibotrys Rhizoma regulates pulmonary lipid metabolic homeostasis and the ERK-cPLA2 pathway to alleviate asthma in mice

BACKGROUND

Asthma is a complex disease with mechanisms involving multiple factors, and there is still a lack of highly effective and low-side-effect drugs. Traditional Chinese medicine Fagopyrum Dibotrys Rhizoma (FDR) has been applied for the treatment of acute and chronic bronchitis as well as bronchial asthma due to its favorable pharmacological activity. However, the exact mechanism of FDR remains unclear.

OBJECTIVE

A mouse model of asthma was created using OVA and HDM. To investigate the mechanism of FDR in asthma treatment, a combination of network pharmacology, lipidomics, and molecular biology approaches was employed.

METHODS

To evaluate the therapeutic effects of FDR on asthma, we established two distinct models of asthma in C57BL/6 J mice using OVA and HDM, respectively. We then employed LC-MS to analyze the major chemical constituents in FDR. Next, the network pharmacology approach was used to predict the potential targets and mechanisms of FDR in asthma treatment. Additionally, lipidomics analysis of mouse serum was conducted using LC-MS. Finally, the impact of FDR on the ERK -cPLA2 signaling pathway was investigated through Western Blotting assay.

RESULTS

FDR treatment has been shown to improve histomorphological changes, lung function and inflammation in models of OVA and HDM-induced asthma. Using UPLC/LTQ-Orbitrap-MS, we were able to identify 12 potential active components. Network pharmacology analysis revealed that FDR shares 75 targets with asthma. Further analysis using GO and KEGG pathways demonstrated the involvement of key pathways such as PI3K-Akt, TNF, and MAPK. Additionally, lipidomics analysis of the serum from OVA and HDM induced asthma mice showed disturbances in lipid metabolism, which were effectively ameliorated by FDR treatment. Mechanistically, FDR inhibits ERK1/2-cPLA2, leading to a reduction in lysophospholipids and restoration of lipid balance, thereby aiding in the treatment of asthma.

CONCLUSION

FDR has been shown to improve lipid metabolism disorder in the serum of asthmatic mice, thereby potentially serving as a treatment for asthma. This can be achieved by regulating the activation levels of ERK1/2 and p38MAPK. Consequently, the production of lysophosphatide is reduced, thereby alleviating the disorder of lipid metabolism and achieving the desired therapeutic effect in asthma treatment.

Mediated Mendelian randomization analysis to determine the role of immune cells in regulating the effects of plasma metabolites on childhood asthma

Childhood asthma is a chronic inflammatory disease of the airways, the pathogenesis of which involves multiple factors including genetic predisposition, environmental exposure, and immune system regulation. To date, the causal relationships between immune cells, plasma metabolites, and childhood asthma remain undetermined. Therefore, we aim to utilize the Mendelian randomization approach to assess the causal relationships among immune cells, plasma metabolites, and childhood asthma. This study employed the Mendelian randomization approach to investigate how immune cells influenced the risk of childhood asthma by modulating the levels of plasma metabolites. Five Mendelian randomization methods-inverse variance weighted, weighted median, Mendelian randomization-Egger, simple mode, and weighted mode-were utilized to explore the causal relationships among 731 types of immune cells, 1400 plasma metabolites, and childhood asthma. The instrumental variables for the 731 immune cells and 1400 plasma metabolites were derived from a genome-wide association study meta-analysis. Additionally, sensitivity analyses were conducted to examine the robustness of the results, potential heterogeneity, and pleiotropy. The inverse variance weighted results indicated that HLA DR on dendritic cells (DC) is a risk factor for childhood asthma (OR: 1.08, 95% CI: 1.02-1.14). In contrast, HLA DR on DC acts as a protective factor against elevated catechol glucuronide levels (OR: 0.94, 95% CI: 0.91-0.98), while catechol glucuronide levels themselves serve as a protective factor for childhood asthma (OR: 0.73, 95% CI: 0.60-0.89). Thus, HLA DR on DC can exert a detrimental effect on childhood asthma through the negative regulation of catechol glucuronide levels. The mediating effect was 0.018, accounting for a mediation effect proportion of 23.4%. This study found that HLA DR on DC can exert a risk effect on childhood asthma through the negative regulation of catechol glucuronide levels, providing new strategies for the prevention and treatment of childhood asthma and guiding future research and clinical practice.

Presence of sputum IgG against eosinophilic inflammatory proteins in asthma

Background

Sputum immunoglobulin G (Sp-IgG) has been discovered to induce cytolytic extracellular trap cell death in eosinophils, suggesting a potential autoimmune mechanism contributing to asthma. This study aimed to explore the potential origin of Sp-IgG and identify clinically relevant subtypes of Sp-IgG that may indicate autoimmune events in asthma.

Methods

This study included 165 asthmatic patients and 38 healthy volunteers. We measured Sp-IgG and its five subtypes against eosinophil inflammatory proteins (Sp-IgGEPs), including eosinophil peroxidase, eosinophil major basic protein, eosinophil-derived neurotoxin, eosinophil cationic protein, and Charcot-Leyden Crystal protein in varying asthma severity. Clinical and Mendelian randomization (MR) analyses were conducted. A positive Sp-IgGEPs signature (Sp-IgGEPs+) was defined when any of the five Sp-IgGEPs values exceeded the predefined cutoff thresholds, calculated as the mean values of healthy controls plus twice the standard deviation.

Results

The levels of Sp-IgG and Sp-IgGEPs were significantly elevated in moderate/severe asthma than those in mild asthma/healthy groups (all p < 0.05). Sp-IgG levels were positively correlated with airway eosinophil and Sp-IgGEPs. MR analysis showed causality between eosinophil and IgG (OR = 1.02, 95%CI = 1.00-1.04, p = 0.020), and elevated IgG was a risk factor for asthma (OR = 2.05, 95%CI = 1.00-4.17, p = 0.049). Subjects with Sp-IgGEPs+ exhibited worse disease severity and served as an independent risk factor contributing to severe asthma (adjusted-OR = 5.818, adjusted-95% CI = 2.193-15.431, adjusted-p < 0.001). Receiver operating characteristic curve analysis demonstrated that the combination of Sp-IgGEPs+ with non-allergic status, an ACT score < 15, and age ≥ 45 years, effectively predicted severe asthma (AUC = 0.84, sensitivity = 86.20%, specificity = 67.80%).

Conclusion

This study identifies a significant association between airway eosinophilic inflammation, Sp-IgG, and asthma severity. The Sp-IgGEPs panel potentially serves as the specific biomarker reflecting airway autoimmune events in asthma.

Combining Federated Machine Learning and Qualitative Methods to Investigate Novel Pediatric Asthma Subtypes: Protocol for a Mixed Methods Study

BACKGROUND

Pediatric asthma is a heterogeneous disease; however, current characterizations of its subtypes are limited. Machine learning (ML) methods are well-suited for identifying subtypes. In particular, deep neural networks can learn patient representations by leveraging longitudinal information captured in electronic health records (EHRs) while considering future outcomes. However, the traditional approach for subtype analysis requires large amounts of EHR data, which may contain protected health information causing potential concerns regarding patient privacy. Federated learning is the key technology to address privacy concerns while preserving the accuracy and performance of ML algorithms. Federated learning could enable multisite development and implementation of ML algorithms to facilitate the translation of artificial intelligence into clinical practice.

OBJECTIVE

The aim of this study is to develop a research protocol for implementation of federated ML across a large clinical research network to identify and discover pediatric asthma subtypes and their progression over time.

METHODS

This mixed methods study uses data and clinicians from the OneFlorida+ clinical research network, which is a large regional network covering linked and longitudinal patient-level real-world data (RWD) of over 20 million patients from Florida, Georgia, and Alabama in the United States. To characterize the subtypes, we will use OneFlorida+ data from 2011 to 2023 and develop a research-grade pediatric asthma computable phenotype and clinical natural language processing pipeline to identify pediatric patients with asthma aged 2-18 years. We will then apply federated learning to characterize pediatric asthma subtypes and their temporal progression. Using the Promoting Action on Research Implementation in Health Services framework, we will conduct focus groups with practicing pediatric asthma clinicians within the OneFlorida+ network to investigate the clinical utility of the subtypes. With a user-centered design, we will create prototypes to visualize the subtypes in the EHR to best assist with the clinical management of children with asthma.

RESULTS

OneFlorida+ data from 2011 to 2023 have been collected for 411,628 patients aged 2-18 years along with 11,156,148 clinical notes. We expect to complete the computable phenotyping within the first year of the project, followed by subtyping during the second and third years, and then will perform the focus groups and establish the user-centered design in the fourth and fifth years of the project.

CONCLUSIONS

Pediatric asthma subtypes incorporating RWD from diverse populations could improve patient outcomes by moving the field closer to precision pediatric asthma care. Our privacy-preserving federated learning methodology and qualitative implementation work will address several challenges of applying ML to large, multicenter RWD data.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/57981.