Association Between Blood Eosinophils and Neutrophils With Clinical Features in Adult-Onset Asthma

Developmental perfluorooctane sulfonic acid exposure exacerbates house dust mite induced allergic responses in adult mice

Perfluorooctane sulfonic acid (PFOS) is a long-chain per- and polyfluoroalkyl substance (PFAS), a persistent organic pollutant, which has been used in aqueous film-forming foams. Emerging epidemiological evidence indicates a significant body burden of PFOS is observed in the lungs. Furthermore, developmental PFOS exposure dysregulates lung development and exacerbates eosinophilic inflammation, which are critical risk factors for asthma. However, it is unknown whether PFOS exerts sex-dependent effects on house dust mite (HDM) induced asthmatic progression and allergic inflammation. In this study, timed pregnant Balb/cJ dams were dosed orally via PFOS (1.0 mg/kg/d) spiked or vehicle control mealworms from gestational day (GD) 0.5 to postnatal day (PND) 21. Subsequently, HDM (30 μg/day) was administered starting at PND 77-82 for 10 days, and the mice were sacrificed 48 h after their final treatment. The serum and lung PFOS concentrations were 3.391 ± 0.189 μg/mL and 3.567 ± 0.1676 μg/g in the offspring, respectively. Male mice exposed to PFOS + HDM showed higher total cell counts in bronchoalveolar lavage fluid (BALF), macrophage counts, and eosinophil counts compared to mice exposed to HDM alone. Female mice exposed to PFOS + HDM had increased BALF eosinophil percentage, mucous production, alternatively activated (M2) macrophage polarization, and M2-associated gene expression compared to female mice exposed to HDM alone. PFOS exposure had no significant effect on HDM-induced IL-4, IL-5, or IL-13, but RANTES was further elevated in female mice. Overall, our data suggest that developmental PFOS exposure increased the risk of exacerbated eosinophilic inflammation and M2 polarization, which were more severe in female mice, suggesting sex-dependent developmental effects of PFOS on allergic airway responses.

Progress in research on induced sputum in asthma: a narrative review

OBJECTIVE

To explore the clinical significance of induced sputum in asthma through a retrospective analysis of induced sputum in patients with asthma.

DATA SOURCES

The data and references cited in this article were obtained from PubMed, Sci-Hub, and Web of Science.

STUDY SELECTION

Observational studies with reliable data were selected.

CONCLUSIONS

The cytological count, -omics, and pathogen detection of induced sputum are helpful for the clinical diagnosis of asthma and in guiding medication choices.

[Assessment of blood eosinophil count in respiratory disease from primary care]

Most physicians in general, and family physicians in particular, are familiar with certain parameters when ordering a hematological study, such as hemoglobin (including hematocrit and its features), leukocytes (including lymphocytes) and platelets. Nevertheless, there are two values that we use to overlook which are eosinophils and basophils. Specifically, eosinophils have a tendency to increase with allergic pathology. This article focuses on this type of cells, helping to interpret the values obtained and highlighting their importance in two of the most frequent respiratory pathologies in primary care: asthma and COPD. In addition to observing how the increase or normality of these parameters condition the diagnosis, phenotype and even the treatment.

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.

[Diagnostic efficacy of serum 14-3-3β protein combined with fractional exhaled nitric oxide and conventional ventilatory lung function parameters for bronchial asthma in children]

OBJECTIVES

To explore the diagnostic efficacy of serum 14-3-3β protein combined with fractional exhaled nitric oxide (FeNO) and conventional ventilatory lung function parameters in diagnosing bronchial asthma (referred to as "asthma") in children.

METHODS

A prospective study included 136 children initially diagnosed with asthma during an acute episode as the asthma group, and 85 healthy children undergoing routine health checks as the control group. The study compared the differences in serum 14-3-3β protein concentrations between the two groups, analyzed the correlation of serum 14-3-3β protein with clinical indices, and evaluated the diagnostic efficacy of combining 14-3-3β protein, FeNO, and conventional ventilatory lung function parameters for asthma in children.

RESULTS

The concentration of serum 14-3-3β protein was higher in the asthma group than in the control group (P<0.001). Serum 14-3-3β protein showed a positive correlation with the percentage of neutrophils and total serum immunoglobulin E, and a negative correlation with conventional ventilatory lung function parameters (P<0.05). Cross-validation of combined indices showed that the combination of 14-3-3β protein, FeNO, and the percentage of predicted value of forced expiratory flow at 75% of lung volume had an area under the curve of 0.948 for predicting asthma, with a sensitivity and specificity of 88.9% and 93.7%, respectively, demonstrating good diagnostic efficacy (P<0.001). The model had the best extrapolation.

CONCLUSIONS

The combination of serum 14-3-3β protein, FeNO, and the percentage of predicted value of forced expiratory flow at 75% of lung volume can significantly improve the diagnostic efficacy for asthma in children. Citation:Chinese Journal of Contemporary Pediatrics, 2024, 26(7): 723-729.

Precision medicine for severe asthma - Biological targeted therapy

Severe asthma is a complex and heterogeneous chronic airway inflammatory disease. Current treatment strategies are increasingly focused on disease classification, facilitating the transition towards personalized medicine by integrating biomarkers and monoclonal antibodies for tailored therapeutic approaches. Several approved biological agents, including anti-immunoglobulin E (IgE), anti-interleukin (IL)-4, anti-IL-5, and anti-thymic stromal lymphopoietin (TSLP) monoclonal antibodies, have demonstrated significant efficacy in reducing asthma exacerbations, eosinophil counts, improving lung function, minimizing oral corticosteroid usage, and enhancing patients' quality of life. The utilization of these biological agents has brought about profound transformations in the management of severe asthma. This article provides a comprehensive review on biomarkers and biological agents for severe asthma while emphasizing the increasing importance of further research into its pathogenesis and novel treatment modalities.

Inhibition of phosphoinositide 3-kinase activity attenuates neutrophilic airway inflammation and inhibits pyrin domain-containing 3 inflammasome activation in an ovalbumin-lipopolysaccharide-induced asthma murine model

BACKGROUND

Existing investigations suggest that the blockade of phosphoinositide 3-kinase (PI3K) activity contributes to inflammatory solution in allergic asthma, but whether this inhibition directly attenuates neutrophilic airway inflammation in vivo is still unclear. We explored the pharmacological effects of LY294002, a specific inhibitor of PI3K on the progression of neutrophilic airway inflammation and investigated the underlying mechanism.

METHODS AND RESULTS

Female C57BL/6 mice were intranasally sensitized with ovalbumin (OVA) together with lipopolysaccharide (LPS) on days 0 and 6, and challenged with OVA on days 14-17 to establish a neutrophilic airway disease model. In the challenge phase, a subset of mice was treated intratracheally with LY294002. We found that treatment of LY294002 attenuates clinic symptoms of inflammatory mice. Histological studies showed that LY294002 significantly inhibited inflammatory cell infiltration and mucus production. The treatment also significantly inhibited OVA-LPS induced increases in inflammatory cell counts, especially neutrophil counts, and IL-17 levels in bronchoalveolar lavage fluid (BALF). LY294002 treated mice exhibited significantly increased IL-10 levels in BALF compared to the untreated mice. In addition, LY294002 reduced the plasma concentrations of IL-6 and IL-17. The anti-inflammatory effects of LY29402 were correlated with the downregulation of NLRP3 inflammasome.

CONCLUSIONS

Our findings suggested that LY294002 as a potential pharmacological target for neutrophilic airway inflammation.

Proteomic signatures of eosinophilic and neutrophilic asthma from serum and sputum

BACKGROUND

Eosinophilic and neutrophilic asthma defined by high levels of blood and sputum eosinophils and neutrophils exemplifies the inflammatory heterogeneity of asthma, particularly severe asthma. We analysed the serum and sputum proteome to identify biomarkers jointly associated with these different phenotypes.

METHODS

Proteomic profiles (N = 1129 proteins) were assayed in sputum (n = 182) and serum (n = 574) from two cohorts (U-BIOPRED and ADEPT) of mild-moderate and severe asthma by SOMAscan. Using least absolute shrinkage and selection operator (LASSO)-penalised logistic regression in a stability selection framework, we sought sparse sets of proteins associated with either eosinophilic or neutrophilic asthma with and without adjustment for established clinical factors including oral corticosteroid use and forced expiratory volume.

FINDINGS

We identified 13 serum proteins associated with eosinophilic asthma, including 7 (PAPP-A, TARC/CCL17, ALT/GPT, IgE, CCL28, CO8A1, and IL5-Rα) that were stably selected while adjusting for clinical factors yielding an AUC of 0.84 (95% CI: 0.83-0.84) compared to 0.62 (95% CI: 0.61-0.63) for clinical factors only. Sputum protein analysis selected only PAPP-A (AUC = 0.81 [95% CI: 0.80-0.81]). 12 serum proteins were associated with neutrophilic asthma, of which 5 (MMP-9, EDAR, GIIE/PLA2G2E, IL-1-R4/IL1RL1, and Elafin) complemented clinical factors increasing the AUC from 0.63 (95% CI: 0.58-0.67) for the model with clinical factors only to 0.89 (95% CI: 0.89-0.90). Our model did not select any sputum proteins associated with neutrophilic status.

INTERPRETATION

Targeted serum proteomic profiles are a non-invasive and scalable approach for subtyping of neutrophilic and eosinophilic asthma and for future functional understanding of these phenotypes.

FUNDING

U-BIOPRED has received funding from the Innovative Medicines Initiative (IMI) Joint Undertaking under grant agreement no. 115010, resources of which are composed of financial contributions from the European Union's Seventh Framework Programme (FP7/2007-2013), and European Federation of Pharmaceutical Industries and Associations (EFPIA) companies' in-kind contributions (www.imi.europa.eu). ADEPT was funded by Johnson & Johnson/Janssen pharmaceutical Company.

Personalized Medicine in Severe Asthma: From Biomarkers to Biologics

Severe asthma is a complex and heterogeneous clinical condition presented as chronic inflammation of the airways. Conventional treatments are mainly focused on symptom control; however, there has been a shift towards personalized medicine. Identification of different phenotypes driven by complex pathobiological mechanisms (endotypes), especially those driven by type-2 (T2) inflammation, has led to improved treatment outcomes. Combining biomarkers with T2-targeting monoclonal antibodies is crucial for developing personalized treatment strategies. Several biological agents, including anti-immunoglobulin E, anti-interleukin-5, and anti-thymic stromal lymphopoietin/interleukin-4, have been approved for the treatment of severe asthma. These biological therapies have demonstrated efficacy in reducing asthma exacerbations, lowering eosinophil count, improving lung function, diminishing oral corticosteroid use, and improving the quality of life in selected patients. Severe asthma management is undergoing a profound transformation with the introduction of ongoing and future biological therapies. The availability of novel treatment options has facilitated the adoption of phenotype/endotype-specific approaches and disappearance of generic interventions. The transition towards precision medicine plays a crucial role in meticulously addressing the individual traits of asthma pathobiology. An era of tailored strategies has emerged, allowing for the successful targeting of immune-inflammatory responses that underlie uncontrolled T2-high asthma. These personalized approaches hold great promise for improving the overall efficacy and outcomes in the management of severe asthma. This article comprehensively reviews currently available biological agents and biomarkers for treating severe asthma. With the expanding repertoire of therapeutic options, it is becoming increasingly crucial to comprehend the influencing factors, understand the pathogenesis, and track treatment progress in severe asthma.

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

BACKGROUND

Asthma is conventionally stratified as type 2 inflammation (T2)-high or T2-low disease. Identifying T2 status has therapeutic implications for patient management, but a real-world understanding of this T2 paradigm in difficult-to-treat and severe asthma remains limited.

OBJECTIVES

To identify the prevalence of T2-high status in difficult-to-treat asthma patients using a multicomponent definition and compare clinical and pathophysiologic characteristics between patients classified as T2-high and T2-low.

METHODS

We evaluated 388 biologic-naive patients from the Wessex Asthma Cohort of difficult asthma (WATCH) study in the United Kingdom. Type 2-high asthma was defined as 20 parts per billion or greater FeNO , 150 cells/μL or greater peripheral blood eosinophils, the need for maintenance oral corticosteroids, and/or clinically allergy-driven asthma.

RESULTS

This multicomponent assessment identified T2-high asthma in 93% of patients (360 of 388). Body mass index, inhaled corticosteroid dose, asthma exacerbations, and common comorbidities did not differ by T2 status. Significantly worse airflow limitation was found in T2-high compared with T2-low patients (FEV1/FVC 65.9% vs 74.6%). Moreover, 75% of patients defined as having T2-low asthma had raised peripheral blood eosinophils within the preceding 10 years, which left only seven patients (1.8%) who had never had T2 signals. Incorporation of sputum eosinophilia 2% or greater into the multicomponent definition in a subset of 117 patients with induced sputum data similarly found that 96% (112 of 117) met criteria for T2-high asthma, 50% of whom (56 of 112) had sputum eosinophils 2% or greater.

CONCLUSIONS

Almost all patients with difficult-to-treat asthma have T2-high disease; less than 2% of patients never display T2-defining criteria. This highlights a need to assess T2 status comprehensively in clinical practice before labeling a patient with difficult-to-treat asthma as T2-low.

T-helper cells and their cytokines in pathogenesis and treatment of asthma

Prosperous advances in understanding the cellular and molecular mechanisms of chronic inflammation and airway remodeling in asthma have been made over the past several decades. Asthma is a chronic inflammatory disease of the airways characterized by reversible airway obstruction that is self-resolving or remits with treatment. Around half of asthma patients are "Type-2-high" asthma with overexpression of type 2 inflammatory pathways and elevated type 2 cytokines. When stimulated by allergens, airway epithelial cells secrete IL-25, IL-33, and TSLP to derive a Th2 immune response. First ILC2 followed by Th2 cells produces a series of cytokines such as IL-4, IL-5, and IL-13. TFH cells control IgE synthesis by secreting IL-4 to allergen-specific B cells. IL-5 promotes eosinophil inflammation, while IL-13 and IL-4 are involved in goblet cell metaplasia and bronchial hyperresponsiveness. Currently, "Type-2 low" asthma is defined as asthma with low levels of T2 biomarkers due to the lack of reliable biomarkers, which is associated with other Th cells. Th1 and Th17 are capable of producing cytokines that recruit neutrophils, such as IFN-γ and IL-17, to participate in the development of "Type-2-low" asthma. Precision medicine targeting Th cells and related cytokines is essential in the management of asthma aiming at the more appropriate patient selection and better treatment response. In this review, we sort out the pathogenesis of Th cells in asthma and summarize the therapeutic approaches involved as well as potential research directions.