Blood eosinophils in managing preschool wheeze: Lessons learnt from a proof-of-concept trial

Transient Tachypnea of the Newborn and the Association with Preschool Asthma

Rationale: Transient tachypnea of the newborn (TTN) is characterized by respiratory distress in neonates, resulting from delayed clearance of fetal lung fluid. Although traditionally considered a self-limited condition, recent studies have indicated a potential association between TTN and an increased risk for respiratory infections during infancy. Objectives: This study investigates the possible link between TTN and healthcare utilization for asthma during childhood. Methods: This retrospective, case-control study used nationwide electronic records from Clalit Healthcare Services, Israel. The study included term infants born between 2011 and 2018 who were diagnosed with TTN (TTN+) and a control group without TTN (TTN-). The primary outcomes were asthma-related healthcare utilization up to age 6 years. Propensity score matching was used to adjust for potential confounders. Results: The study included 645 children with TTN and 187,809 in the TTN- group. In prematching analysis, the TTN+ group had a higher incidence of cesarean delivery and male sex. Postmatching, demographic, and clinical differences were balanced. Children in the TTN+ group had significantly higher rates of emergency room visits for asthma (2.05 times higher; P value (Pv) < 0.001; 95% confidence interval [CI], 1.46-2.89), asthma diagnoses (38% increase; Pv < 0.001; 95% CI, 1.18-1.51), and prescriptions for short-acting β-agonists (28% increase; Pv = 0.002; 95% CI, 1.1-2.89) than control subjects. These associations remained significant after adjusting for confounders. Conclusions: The findings suggest that TTN may be associated with a higher risk of developing asthma in childhood. This study may enhance our understanding of the potential long-term respiratory implications of TTN and could inform clinical follow-up strategies for affected infants.

Update in paediatric asthma

PURPOSE OF REVIEW

The field of paediatric asthma is rapidly moving, with the advent of new biologicals for severe asthma and increased understanding of preschool wheeze amongst other developments and insights.

RECENT FINDINGS

There is increasing evidence of efficacy in children for biologics directed against Type 2 inflammation (especially mepolizumab and dupilumab) as well encouraging evidence that Tezepelumab may be effective against Type 2 low phenotypes. The importance of airway remodelling and infection in the pathophysiology of preschool wheeze is increasingly appreciated. The treatment of preschool wheeze is moving from symptom-based to biomarker driven therapies. Other important areas are prediction of risk of asthma attacks, the SMART regime, the importance of climate change and reducing greenhouse gas emissions from inhalers while ensuring adequate therapy for young children, the association of early adverse environmental factors including childhood poverty and deprivation and the switch to race-neutral lung function equations.

SUMMARY

We are increasingly moving towards personalized medicine and the use of biomarkers to guide treatment of wheeze at all ages, but we need to move from counting cells to determining their functional status. Airway wall structural changes rather than inflammation may drive the progression of preschool wheeze to school age asthma.

Managing preschool wheeze: a qualitative study of parents' views and experiences

OBJECTIVE

The aim of this study was to explore parents' views and experiences of managing preschool wheeze, including opinions on the use of investigations to inform treatment pathways.

DESIGN

Purposive sampling was used to recruit 16 participants from 14 families across England and Wales. Qualitative data were collected via semi-structured interviews with parents of children aged 1-5 years with preschool wheeze, conducted on Microsoft (MS) Teams. Data were transcribed and analysed using thematic analysis, facilitated by NVivo software package.

RESULTS

Analysis generated four themes: (1) pathway to diagnosis, (2) medication management, (3) living with preschool wheeze and (4) improving preschool wheeze healthcare. Findings suggest a negative impact of preschool wheeze on families' lives, including high levels of worry and limiting capacity for work and travel. Barriers to effective management of preschool wheeze included inconsistent terminologies and diagnostic uncertainty alongside limited education and management support. Other barriers included parental concerns about medications, delayed investigations and challenges with accessing specialist care. Parents were in favour of performing investigations to guide treatment pathways.

CONCLUSION

Parents' views highlight the problem of diagnosing and treating preschool wheeze at multiple system levels. To improve management and ensure that services for children with preschool wheeze are effective, there is an urgent need for consistent terminology, a unified approach to guide investigations and treatments and for upskilling healthcare professionals in primary and secondary care.

Preschool wheeze and asthma endotypes- implications for future therapy

INTRODUCTION

Preschool wheeze and school-aged asthma present a large healthcare burden. Both conditions are now recognized to be heterogeneous, with similar symptom presentation but likely different underlying lung pathology.

AREAS COVERED

Current treatment options for preschool wheeze are constrained by extrapolations from the management of school-aged children with asthma. While most cases of asthma at school age are caused by classical atopic, eosinophilic, Type-2 driven asthma, only a quarter of preschool children with wheeze fall into this category. Targeting treatment to specific underlying mechanisms resulting in preschool wheeze may alter the progression to school age asthma. Novel biologics have revolutionized the management of severe, treatment-resistant school age asthma, but a limited evidence base limits their use in young children. There are several potential future non-steroid-based treatment options in development, of which bacterial lysates show the most promise.

EXPERT OPINION

Effective treatment of preschool wheeze may preserve lung function into later life, which may alter the progression trajectory toward school age asthma. Endotype-driven management will enable more effective treatment of both preschool wheeze and school age asthma.

European Respiratory Society statement on preschool wheezing disorders: updated definitions, knowledge gaps and proposed future research directions

Since the publication of the European Respiratory Society (ERS) task force reports on the management of preschool wheezing in 2008 and 2014, a large body of evidence has accumulated suggesting that the clinical phenotypes that were proposed (episodic (viral) wheezing and multiple-trigger wheezing) do not relate to underlying airway pathology and may not help determine response to treatment. Specifically, using clinical phenotypes alone may no longer be appropriate, and new approaches that can be used to inform clinical care are needed for future research. This ERS task force reviewed the literature published after 2008 related to preschool wheezing and has suggested that the criteria used to define wheezing disorders in preschool children should include age of diagnosis (0 to <6 years), confirmation of wheezing on at least one occasion, and more than one episode of wheezing ever. Furthermore, diagnosis and management may be improved by identifying treatable traits, including inflammatory biomarkers (blood eosinophils, aeroallergen sensitisation) associated with type-2 immunity and differential response to inhaled corticosteroids, lung function parameters and airway infection. However, more comprehensive use of biomarkers/treatable traits in predicting the response to treatment requires prospective validation. There is evidence that specific genetic traits may help guide management, but these must be adequately tested. In addition, the task force identified an absence of caregiver-reported outcomes, caregiver/self-management options and features that should prompt specialist referral for this age group. Priorities for future research include a focus on identifying 1) mechanisms driving preschool wheezing; 2) biomarkers of treatable traits and efficacy of interventions in those without allergic sensitisation/eosinophilia; 3) the need to include both objective outcomes and caregiver-reported outcomes in clinical trials; 4) the need for a suitable action plan for children with preschool wheezing; and 5) a definition of severe/difficult-to-treat preschool wheezing.

A systematic review and meta-analysis on absolute eosinophil counts and the risk of asthma in preschool children with wheezing: An EAACI Task Force Report

Preschool children with wheezing disorders pose diagnostic and therapeutic challenges and consume substantial healthcare resources. Peripheral eosinophil blood count (EBC) has been proposed as a potential indicator for future asthma development. This review by the European Academy of Allergy and Clinical Immunology (EAACI) Preschool Wheeze Task Force aimed to provide systematic evidence for the association between increased EBC and the risk of future asthma, as well as to identify potential cutoff values. In February 2023, a search of PubMed, EMBASE, and Cochrane Library databases was conducted to identify studies comparing EBCs in preschool children with wheezing who continued to wheeze later in life and those who did not. Included observational studies focused on children aged <6 years with a wheezing disorder, assessment of their EBCs, and subsequent asthma status. No language or publication date restrictions were applied. Among the initial 3394 studies screened, 10 were included in the final analysis, involving 1225 patients. The data from these studies demonstrated that high EBC in preschool children with wheezing is associated with future asthma development, with odds ratios of 1.90 (95% CI: 0.45-7.98, p = .38), 2.87 (95% CI: 1.38-5.95, p < .05), and 3.38 (95% CI: 1.72-6.64, p < .05) for cutoff values in the <300, 300-449, and ≥450 cells/μL ranges, respectively. Defining a specific cutoff point for an elevated EBC lacks consistency, but children with EBC >300 cells/μL are at increased risk of asthma. However, further research is needed due to the limitations of the included studies. Future investigations are necessary to fully elucidate the discussed association.

Phenotype and endotype based treatment of preschool wheeze

INTRODUCTION

Preschool wheeze (PSW) is a significant public health issue, with a high presentation rate to emergency departments, recurrent symptoms, and severe exacerbations. A heterogenous condition, PSW comprises several phenotypes that may relate to a range of pathobiological mechanisms. However, treating PSW remains largely generalized to inhaled corticosteroids and a short acting beta agonist, guided by symptom-based labels that often do not reflect underlying pathways of disease.

AREAS COVERED

We review the observable features and characteristics used to ascribe phenotypes in children with PSW and available pathobiological evidence to identify possible endotypes. These are considered in the context of treatment options and future research directions. The role of machine learning (ML) and modern analytical techniques to identify patterns of disease that distinguish phenotypes is also explored.

EXPERT OPINION

Distinct clusters (phenotypes) of severe PSW are characterized by different underlying mechanisms, some shared and some unique. ML-based methodologies applied to clinical, biomarker, and environmental data can help design tools to differentiate children with PSW that continues into adulthood, from those in whom wheezing resolves, identifying mechanisms underpinning persistence and resolution. This may help identify novel therapeutic targets, inform mechanistic studies, and serve as a foundation for stratification in future interventional therapeutic trials.

Basic clinical management of preschool wheeze

Preschool wheeze is very common and often difficult to treat. Most children do not require any investigations; only a detailed history and physical examination to ensure an alternative diagnosis is not being missed; and the differential diagnosis, and hence investigation protocols for the child in whom a major illness is suspected, shows geographical variation. The pattern of symptoms may be divided into episodic viral and multiple trigger to guide treatment, but the pattern of symptoms must be re-assessed regularly. However, symptom patterns are a poor guide to underlying pathology. Attention to the proper use of spacers, and adverse environmental exposures such as tobacco smoke exposure, is essential. There are no disease-modifying therapies, so therapy is symptomatic. This paper reviews recent advances in treatment, including new data on the place of leukotriene receptor antagonists, prednisolone for acute attacks of wheeze, and antibiotics, based on new attempts to understand the underlying pathology in a way that is clinically practical.

Blood Eosinophils for Prediction of Exacerbation in Preschool Children With Recurrent Wheezing

BACKGROUND

Although clinical features of type 2 inflammation have been associated with poorer longitudinal outcomes in preschool children with recurrent wheezing, it remains difficult to predict which children are at highest risk for poor outcomes during a routine clinical encounter.

OBJECTIVE

We tested the hypothesis that prespecified cut points of blood eosinophil counts would predict exacerbation and treatment response outcomes in preschool children with recurrent wheezing and that prediction could be improved with the addition of a second biomarker.

METHODS

Data from 3 clinical trials of 1,074 preschool children aged 12 to 71 months with recurrent wheezing were merged. The primary outcome was the occurrence of any exacerbation during follow-up. Secondary outcomes included the annualized rate of wheezing exacerbations and the occurrence of any exacerbation requiring hospitalization. Exploratory analyses focused on exacerbation outcomes, offline exhaled nitric oxide concentrations, and caregiver-reported asthma control scores after inhaled corticosteroid treatment initiation.

RESULTS

Each blood eosinophil cut point was associated with increased odds of exacerbation, higher exacerbation rates, and greater hospitalization occurrence in preschool children with recurrent wheezing. However, outcome detection was improved in children with more elevated blood eosinophil counts. Addition of a second biomarker of type 2 inflammation improved outcome detection and was further associated with an improved response to initiation of daily inhaled corticosteroids in exploratory analyses. However, the specificity of blood eosinophils was poor.

CONCLUSIONS

Although validation studies are warranted, blood eosinophil cut points may be useful for clinical assessment and future studies of exacerbation and treatment response in preschool children with recurrent wheezing.

Caregiver's sense of coherence and adherence to paediatric asthma treatment

Asthma is a chronic respiratory condition that needs to be well controlled to avoid compromising patients' quality of life. In the paediatric population, the role of caregivers is essential in this process. Moreover, adequate asthma control is integral to a child's emotional well-being and to improving the child's ability to participate fully in family and social life. One of the main reasons for uncontrolled asthma is low adherence to treatment, by patients and caregivers. Identifying factors mediating the involvement and participation of caregivers through evaluations of caregivers' sense of coherence can help in the adoption of strategies aimed at effectively directing adherence behaviour through educational and motivational interventions. The goal of this review article is to provide an overview of the sense of coherence as a construct of Antonovsky's salutogenic theory, and to identify its role as a key piece in the successful management of asthma in children.

Exhaled Breath Analysis for Investigating the Use of Inhaled Corticosteroids and Corticosteroid Responsiveness in Wheezing Preschool Children

Exhaled breath analysis has great potential in diagnosing various respiratory and non-respiratory diseases. In this study, we investigated the influence of inhaled corticosteroids (ICS) on exhaled volatile organic compounds (VOCs) of wheezing preschool children. Furthermore, we assessed whether exhaled VOCs could predict a clinical steroid response in wheezing preschool children. We performed a crossover 8-week ICS trial, in which 147 children were included. Complete data were available for 89 children, of which 46 children were defined as steroid-responsive. Exhaled VOCs were measured by GC-tof-MS. Statistical analysis by means of Random Forest was used to investigate the effect of ICS on exhaled VOCs. A set of 20 VOCs could best discriminate between measurements before and after ICS treatment, with a sensitivity of 73% and specificity of 67% (area under ROC curve = 0.72). Most discriminative VOCs were branched C11H24, butanal, octanal, acetic acid and methylated pentane. Other VOCs predominantly included alkanes. Regularised multivariate analysis of variance (rMANOVA) was used to determine treatment response, which showed a significant effect between responders and non-responders (p < 0.01). These results show that ICS significantly altered the exhaled breath profiles of wheezing preschool children, irrespective of clinical treatment response. Furthermore, exhaled VOCs were capable of determining corticosteroid responsiveness in wheezing preschool children.

How to Choose the Correct Drug in Severe Pediatric Asthma

When a child with severe asthma (asthma defined clinically for the purposes of this review as wheeze, breathlessness, and chest tightness sometimes with cough) does not respond to treatment, it is important to be sure that an alternative or additional diagnosis is not being missed. In school age children, the next step is a detailed protocolized assessment to determine the nature of the problem, whether within the airway or related to co-morbidities or social/environmental factors, in order to personalize the treatment. For example, those with refractory difficult asthma due to persistent non-adherence may benefit from using budesonide and formoterol combined in a single inhaler [single maintenance and reliever treatment (SMART)] as both a reliever and preventer. For those with steroid-resistant Type 2 airway inflammation, the use of biologicals such as omalizumab and mepolizumab should be considered, but for mepolizumab at least, there is a paucity of pediatric data. Protocols are less well developed in preschool asthma, where steroid insensitive disease is much more common, but the use of two simple measurements, aeroallergen sensitization, and peripheral blood eosinophil count, allows the targeted use of inhaled corticosteroids (ICSs). There is also increasing evidence that chronic airway infection may be important in preschool wheeze, increasing the possibility that targeted antibiotics may be beneficial. Asthma in the first year of life is not driven by Type 2 inflammation, so beyond avoiding prescribing ICSs, no evidence based recommendations can be made. In the future, we urgently need to develop objective biomarkers, especially of risk, so that treatment can be targeted effectively; we need to address the scandal of the lack of data in children compared with adults, precluding making evidence-based therapeutic decisions and move from guiding treatment by phenotypes, which will change as the environment changes, to endotype based therapy.