Severe asthma in children

A matched analysis of the use of high flow nasal cannula for pediatric severe acute asthma

RATIONALE

The high-flow nasal cannula (HFNC) device is commonly used to treat pediatric severe acute asthma. However, there is little evidence regarding its effectiveness in real-world practice.

OBJECTIVES

We sought to compare the physiologic effects and clinical outcomes for children treated for severe acute asthma with HFNC versus matched controls.

METHODS

This was a single-center retrospective matched cohort study at a quaternary care children's hospital. Children ages 2-18 hospitalized for severe acute asthma from 2015 to 2022 were included. Encounters receiving treatment with HFNC within the first 24 h of hospitalization were included as cases. Controls were primarily treated with oxygen facemask. Logistic regression 1:1 propensity score matching was done using demographics, initial vital signs, and medications. The primary outcome was an improvement in clinical asthma symptoms in the first 24 h of hospitalization measured as percent change from initial.

MEASUREMENTS AND MAIN RESULTS

Of 693 eligible cases, 443 were matched to eligible controls. Propensity scores were closely aligned between the cohorts, with the only significant difference in clinical characteristics being a higher percentage of patients of Black race in the control group (54.3% vs. 46.6%; p = 0.02). Compared to the matched controls, the HFNC cohort had smaller improvements in heart rate (-11.5% [-20.9; -0.9] vs. -14.7% [-22.6;-5.7]; p < 0.01), respiratory rate (-14.3% [-27.9;5.4] vs. -16.7% [-31.5;0.0]; p = 0.03), and pediatric asthma severity score (-14.3% [-28.6;0.0] vs. -20.0% [-33.3;0.0]; p < 0.01) after 24 h of hospitalization. The HFNC cohort also had longer pediatric intensive care unit (PICU) length of stay (LOS) (1.5 days [1.1;2.1] vs. 1.2 days [0.9;1.8]; p < 0.01) and hospital LOS (2.8 days [2.1;3.8] vs. 2.5 days [1.9;3.4]; p < 0.01). When subgrouping to younger patients (2-3 years old), or those with the highest severity scores (PASS > 9), those treated with HFNC had no difference in clinical symptom improvements but maintained a longer PICU LOS.

CONCLUSIONS

Encounters using HFNC for severe acute pediatric asthma had decreased clinical improvement in 24 h of hospitalization compared to matched controls and increased LOS. Specific subgroups of younger patients and those with the highest severity scores showed no differences in clinical symptom improvement suggesting differential effects in specific patient populations.

Early prediction of pediatric asthma in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort using machine learning

BACKGROUND

Early identification of children at risk of asthma can have significant clinical implications for effective intervention and treatment. This study aims to disentangle the relative timing and importance of early markers of asthma.

METHODS

Using the CHILD Cohort Study, 132 variables measured in 1754 multi-ethnic children were included in the analysis for asthma prediction. Data up to 4 years of age was used in multiple machine learning models to predict physician-diagnosed asthma at age 5 years. Both predictive performance and variable importance was assessed in these models.

RESULTS

Early-life data (≤1 year) has limited predictive ability for physician-diagnosed asthma at age 5 years (area under the precision-recall curve (AUPRC) < 0.35). The earliest reliable prediction of asthma is achieved at age 3 years, (area under the receiver-operator curve (AUROC) > 0.90) and (AUPRC > 0.80). Maternal asthma, antibiotic exposure, and lower respiratory tract infections remained highly predictive throughout childhood. Wheezing status and atopy are the most important predictors of early childhood asthma from among the factors included in this study.

CONCLUSIONS

Childhood asthma is predictable from non-biological measurements from the age of 3 years, primarily using parental asthma and patient history of wheezing, atopy, antibiotic exposure, and lower respiratory tract infections.

IMPACT

Machine learning models can predict physician-diagnosed asthma in early childhood (AUROC > 0.90 and AUPRC > 0.80) using ≥3 years of non-biological and non-genetic information, whereas prediction with the same patient information available before 1 year of age is challenging. Wheezing, atopy, antibiotic exposure, lower respiratory tract infections, and the child's mother having asthma were the strongest early markers of 5-year asthma diagnosis, suggesting an opportunity for earlier diagnosis and intervention and focused assessment of patients at risk for asthma, with an evolving risk stratification over time.

Institutional Variability in Respiratory Support Use for Pediatric Critical Asthma: A Multicenter Retrospective Study

Rationale: Over 20,000 children are hospitalized in the United States for asthma every year. Although initial treatment guidelines are well established, there is a lack of high-quality evidence regarding the optimal respiratory support devices for these patients.Objectives: The objective of this study was to evaluate institutional and temporal variability in the use of respiratory support modalities for pediatric critical asthma.Methods: We conducted a retrospective cohort study using data from the Virtual Pediatrics Systems database. Our study population included children older than 2 years old admitted to a VPS contributing pediatric intensive care unit from January 2012 to December 2021 with a primary diagnosis of asthma or status asthmaticus. We evaluated the percentage of encounters using a high-flow nasal cannula (HFNC), continuous positive airway pressure (CPAP), noninvasive bilevel positive pressure ventilation (NIV), and invasive mechanical ventilation (IMV) for all institutions, then divided institutions into quintiles based on the volume of patients. We created logistic regression models to determine the influence of institutional volume and year of admission on respiratory support modality use. We also conducted time-series analyses using Kendall's tau.Results: Our population included 77,115 patient encounters from 163 separate institutions. Institutional use of respiratory modalities had significant variation in HFNC (28.3%, interquartile range [IQR], 11.0-49.0%; P < 0.01), CPAP (1.4%; IQR, 0.3-4.3%; P < 0.01), NIV (8.6%; IQR, 3.5-16.1%; P < 0.01), and IMV (5.1%; IQR, 3.1-8.2%; P < 0.01). Increased institutional patient volume was associated with significantly increased use of NIV (odds ratio [OR], 1.33; 1.29-1.36; P < 0.01) and CPAP (OR, 1.20; 1.15-1.25; P < 0.01), and significantly decreased use of HFNC (OR, 0.80; 0.79-0.81; P < 0.01) and IMV (OR, 0.82; 0.79-0.86; P < 0.01). Time was also associated with a significant increase in the use of HFNC (11.0-52.3%; P < 0.01), CPAP (1.6-5.4%; P < 0.01), and NIV (3.7-21.2%; P < 0.01), whereas there was no significant change in IMV use (6.1-4.0%; P = 0.11).Conclusions: Higher-volume centers are using noninvasive positive pressure ventilation more frequently for pediatric critical asthma and lower frequencies of HFNC and IMV. Treatment with HFNC, CPAP, and NIV for this population is increasing in the last decade.

Assessment of long-term safety and efficacy of dupilumab in children with asthma (LIBERTY ASTHMA EXCURSION): an open-label extension study

BACKGROUND

Dupilumab efficacy and safety in children aged 6-11 years with uncontrolled, moderate-to-severe asthma were shown in the VOYAGE study-a 52-week, multinational, multicentre, phase 3 randomised, double-blind, placebo-controlled trial. We aimed to evaluate the long-term safety and efficacy of dupilumab in children with moderate-to-severe asthma who previously participated in the VOYAGE study.

METHODS

365 of 408 children with moderate-to-severe asthma from VOYAGE enrolled in EXCURSION, a 52 week, open-label extension study conducted at 70 centres across 17 countries. 240 children continued with add-on dupilumab (dosed according to bodyweight: 100 mg for those weighing ≤30 kg and 200 mg for those weighing more than 30 kg at EXCURSION baseline) once every 2 weeks administered by subcutaneous injection (dupilumab/dupilumab group) and 125 children on placebo during VOYAGE initiated dupilumab (100 or 200 mg, according to bodyweight), once every 2 weeks administered by subcutaneous injection (placebo/dupilumab group). Following a protocol amendment, for a subset of children weighing 30 kg or less, the dose was changed to 300 mg once every 4 weeks. The primary endpoint for the open-label extension study was the number and proportion of patients with any treatment-emergent adverse event (TEAE) during the 52-week study period in the overall population (defined as children aged 6-11 years old with moderate-to-severe asthma who previously completed VOYAGE). Statistical analyses were descriptive. This study is registered with ClinicalTrials.gov (NCT03560466; EXCURSION).

FINDINGS

Children who completed VOYAGE were eligible to enrol in EXCURSION between June 21, 2018 and Aug 18, 2020. During EXCURSION, the safety profile and proportion of patients reporting TEAEs were consistent with those observed during the parent study (VOYAGE). In the overall population, 232 (63·6%) of 365 patients experienced at least one TEAE (dupilumab/dupilumab: 147 [61·3%]; placebo/dupilumab: 85 [68·0%]). The most frequently reported TEAEs were nasopharyngitis, pharyngitis, and upper respiratory tract infections.

INTERPRETATION

In EXCURSION, long-term treatment with dupilumab was well tolerated with an acceptable safety profile.

FUNDING

Sanofi and Regeneron Pharmaceuticals.

Wide Institutional Variability in the Treatment of Pediatric Critical Asthma: A Multicenter Retrospective Study

OBJECTIVES

Children with status asthmaticus refractory to first-line therapies of systemic corticosteroids and inhaled beta-agonists often receive additional treatments. Because there are no national guidelines on the use of asthma therapies in the PICU, we sought to evaluate institutional variability in the use of adjunctive asthma treatments and associations with length of stay (LOS) and PICU use.

DESIGN

Multicenter retrospective cohort study.

SETTING

Administrative data from the Pediatric Health Information Systems (PHIS) database.

PATIENTS

All inpatients 2-18 years old were admitted to a PHIS hospital between 2013 and 2021 with a diagnostic code for asthma.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

This study included 213,506 inpatient encounters for asthma, of which 29,026 patient encounters included care in a PICU from 39 institutions. Among these PICU encounters, large variability was seen across institutions in both the number of adjunctive asthma therapies used per encounter (min: 0.6, median: 1.7, max: 2.5, p < 0.01) and types of adjunctive asthma therapies (aminophylline, ipratropium, magnesium, epinephrine, and terbutaline) used. The center-level median hospital LOS ranged from 1 (interquartile range [IQR]: 1, 3) to 4 (3, 6) days. Among all the 213,506 inpatient encounters for asthma, the range of asthma admissions that resulted in PICU admission varied between centers from 5.2% to 47.3%. The average number of adjunctive therapies used per institution was not significantly associated with hospital LOS ( p = 0.81) nor the percentage of encounters with PICU admission ( p = 0.47).

CONCLUSIONS

Use of adjunctive therapies for status asthmaticus varies widely among large children's hospitals and was not associated with hospital LOS or the percentage of encounters with PICU admission. Wide variance presents an opportunity for standardizing care with evidence-based guidelines to optimize outcomes and decrease adverse treatment effects and hospital costs.

GEMA 5.3. Spanish Guideline on the Management of Asthma

The Spanish Guideline on the Management of Asthma, better known by its acronym in Spanish GEMA, has been available for more than 20 years. Twenty-one scientific societies or related groups both from Spain and internationally have participated in the preparation and development of the updated edition of GEMA, which in fact has been currently positioned as the reference guide on asthma in the Spanish language worldwide. Its objective is to prevent and improve the clinical situation of people with asthma by increasing the knowledge of healthcare professionals involved in their care. Its purpose is to convert scientific evidence into simple and easy-to-follow practical recommendations. Therefore, it is not a monograph that brings together all the scientific knowledge about the disease, but rather a brief document with the essentials, designed to be applied quickly in routine clinical practice. The guidelines are necessarily multidisciplinary, developed to be useful and an indispensable tool for physicians of different specialties, as well as nurses and pharmacists. Probably the most outstanding aspects of the guide are the recommendations to: establish the diagnosis of asthma using a sequential algorithm based on objective diagnostic tests; the follow-up of patients, preferably based on the strategy of achieving and maintaining control of the disease; treatment according to the level of severity of asthma, using six steps from least to greatest need of pharmaceutical drugs, and the treatment algorithm for the indication of biologics in patients with severe uncontrolled asthma based on phenotypes. And now, in addition to that, there is a novelty for easy use and follow-up through a computer application based on the chatbot-type conversational artificial intelligence (ia-GEMA).

Metformin Counteracts the Deleterious Effects of Methylglyoxal on Ovalbumin-Induced Airway Eosinophilic Inflammation and Remodeling

Exposure to methylglyoxal (MGO) increases the levels of receptor for advanced glycation end products (RAGE) and reactive-oxygen species (ROS) in mouse airways, exacerbating the inflammatory responses. Metformin scavenges MGO in plasma of diabetic individuals. We investigated if amelioration by metformin of eosinophilic inflammation reflects its ability to inactivate MGO. Male mice received 0.5% MGO for 12 weeks together or not with 2-week treatment with metformin. Inflammatory and remodeling markers were evaluated in bronchoalveolar lavage fluid (BALF) and/or lung tissues of ovalbumin (OVA)-challenged mice. MGO intake elevated serum MGO levels and MGO immunostaining in airways, which were reduced by metformin. The infiltration of inflammatory cells and eosinophils and levels of IL-4, IL-5 and eotaxin significantly increased in BALF and/or lung sections of MGO-exposed mice, which were reversed by metformin. The increased mucus production and collagen deposition by MGO exposure were also significantly decreased by metformin. In MGO group, the increases of RAGE and ROS levels were fully counteracted by metformin. Superoxide anion (SOD) expression was enhanced by metformin. In conclusion, metformin counteracts OVA-induced airway eosinophilic inflammation and remodeling, and suppresses the RAGE-ROS activation. Metformin may be an option of adjuvant therapy to improve asthma in individuals with high levels of MGO.

Whispers of change in preschool asthma phenotypes: Findings in the French ELFE cohort

RATIONALE

Early life asthma phenotyping remains an unmet need in pediatric asthma. In France, severe pediatric asthma phenotyping has been done extensively; however, phenotypes in the general population remain underexplored. Based on the course and severity of respiratory/allergic symptoms, we aimed to identify and characterize early life wheeze profiles and asthma phenotypes in the general population.

METHODS

ELFE is a general population based birth cohort; which recruited 18,329 newborns in 2011, from 320 maternity units nationwide. Data was collected using parental responses to modified versions of ISAAC questionnaire on eczema, rhinitis, food allergy, cough, wheezing, dyspnoea and sleep disturbance due to wheezing at 3 time points: post-natal (2 months), infancy (age 1) and pre-school (age 5). We built a supervised trajectory for wheeze profiles and an unsupervised approach was used for asthma phenotypes. Chi squared (χ2) test or fisher's exact test was used as appropriate (p < 0.05).

RESULTS

Wheeze profiles and asthma phenotypes were ascertained at age 5. Supervised wheeze trajectory of 9161 children resulted in 4 wheeze profiles: Persistent (0.8%), Transient (12.1%), Incident wheezers at age 5 (13.3%) and Non wheezers (73.9%). While 9517 children in unsupervised clusters displayed 4 distinct asthma phenotypes: Mildly symptomatic (70%), Post-natal bronchiolitis with persistent rhinitis (10.2%), Severe early asthma (16.9%) and Early persistent atopy with late onset severe wheeze (2.9%).

CONCLUSION

We successfully determined early life wheeze profiles and asthma phenotypes in the general population of France.

How to interpret spirometry in a child with suspected asthma

Asthma is one of the most common chronic disorders of childhood. The typical symptoms are a result of reversible airway obstruction. There is no 'gold-standard' test to diagnose asthma, but the most commonly used investigation to help with a diagnosis is spirometry. This article outlines some of the technical aspects of spirometry together with how the forced expiration manoeuver and bronchodilator responsiveness testing can be performed and interpreted in a child with suspected asthma.

Severe asthma in children: Description of a large multidisciplinary clinical cohort

BACKGROUND

Children with severe asthma have substantial morbidity and healthcare utilization. Pediatric severe asthma is a heterogeneous disease, and a multidisciplinary approach can improve the diagnosis and management of these children.

METHODS

We reviewed the electronic health records for patients seen in the Severe Asthma Clinic (SAC) at UPMC Children's Hospital of Pittsburgh between August 2012 and October 2019.

RESULTS

Of the 110 patients in whom we extracted data, 46% were female, 48% were Black/African American, and 41% had ≥1 admission to the pediatric intensive care unit (PICU) for asthma. Compared to patients without a PICU admission, those with ≥1 PICU admission were more likely to be non-White (64.4% vs. 41.5%, p = 0.031) and more atopic (eosinophil count geometric mean = 673 vs. 319 cells/mm3 , p = 0.002; total IgE geometric mean = 754 vs. 303 KU/L, p = 0.003), and to have lower pre-bronchodilator FEV1 (58.6% [±18.1%] vs. 69.9% [±18.7%], p = 0.002) and elevated FeNO (60% vs. 22%, p = 0.02). In this cohort, 84% of patients were prescribed high-dose ICS/LABA and 36% were on biologics. Following enrollment in the SAC, severe exacerbations decreased from 3.2/year to 2.2/year (p < 0.0001); compared to the year before joining the SAC, in the following year the group had 106 fewer severe exacerbations.

CONCLUSIONS

This large cohort of children with severe asthma had a high level of morbidity and healthcare utilization. Patients with a history of PICU admissions for asthma were more likely to be nonwhite and highly atopic, and to have lower lung function. Our data support a positive impact of a multidisciplinary clinic on patients with severe childhood asthma.

Asthma Attacks in Children-Challenges and Opportunities

Asthma is the most common chronic disease of childhood worldwide, and is responsible for significant morbidity and mortality in children and young people (CYP). Given the inherent dangers of a child experiencing even a single asthma attack, it is essential to identify and manage modifiable risk factors at every clinical opportunity. Following an attack, there is an opportunity to prevent future attacks by assessing compliance and optimizing asthma control. Careful questioning will allow physicians to identify asthma triggers, barriers to good asthma control, and health beliefs or socioeconomic obstacles that may have contributed to this attack. The vast majority of children with asthma can achieve good symptom control with appropriate use of low-dose inhaled corticosteroids.

Reply to: Challenging the paradigm

We thank M.L. Everard for his interest in our article [1] and thank the Editors for giving us the opportunity to respond. Space constraints precluded us describing the detailed management of extrapulmonary treatable traits, hence the educational aim was to begin to appreciate, but we are happy to refer interested readers to other review articles on the subject [2–4].

Inhaled corticosteroids should be targeted to those with documented airway eosinophilia, not prescribed indiscriminately to all who wheeze. Blind steroid treatment without regard to underlying pathophysiology is not 21st century standard of care.https://bit.ly/34lyaJG

Difficult-to-Treat Asthma Management in School-Age Children

The World Health Organization divides severe asthma into three categories: untreated severe asthma; difficult-to-treat severe asthma; and severe, therapy-resistant asthma. The apparent frequency of severe asthma in the general population of asthmatic children is probably around 5%. Upon referral of these children, it is important to evaluate the diagnosis of asthma carefully before modifying management and applying a long-term monitoring plan. Identification of pathophysiologic phenotypes using objective biomarkers is essential in our routine assessments of severe asthma. Although conventional pharmacologic approaches should be attempted first, there is growing recognition that children with difficult-to-treat asthma may have unique clinical phenotypes that may necessitate alternative treatment approaches including asthma biologics. These new medications, especially those with effects on multiple pathologic features of asthma, raise the hope that new treatment strategies could induce remission. Besides introducing new medications, the opportunity for closer monitoring is feasible with advances in digital health. Therefore, we have the opportunity to improve response to medications, individualize treatment, and monitor response along with potential steps to prevent severe asthma.

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.

The Immune Barrier of Porcine Uterine Mucosa Differs Dramatically at Proliferative and Secretory Phases and Could Be Positively Modulated by Colonizing Microbiota

Endometrial immune response is highly associated with the homeostatic balance of the uterus and embryo development; however, the underlying molecular regulatory mechanisms are not fully elucidated. Herein, the porcine endometrium showed significant variation in mucosal immunity in proliferative and secretory phases by single-cell RNA sequencing. The loose arrangement and high motility of the uterine epithelium in the proliferative phase gave opportunities for epithelial cells and dendritic cells to cross talk with colonizing microbial community, guiding lymphocyte migration into the mucosal and glandular epithelium. The migrating lymphocytes were primarily NK and CD8⁺ T cells, which were robustly modulated by the chemokine signaling. In the secretory phase, the significantly strengthened mechanical mucosal barrier and increased immunoglobulin A alleviated the migration of lymphocytes into the epithelium when the neuro-modulation, mineral uptake, and amino acid metabolism were strongly upregulated. The noticeably increased intraepithelial lymphocytes were positively modulated by the bacteria in the uterine cavity. Our findings illustrated that significant mucosal immunity variation in the endometrium in the proliferative and secretory phases was closely related to intraepithelial lymphocyte migration, which could be modulated by the colonizing bacteria after cross talk with epithelial cells with higher expressions of chemokine.

Severe acute asthma at the pediatric intensive care unit: can we link the clinical phenotypes to immunological endotypes?

INTRODUCTION

The clinical phenotype of severe acute asthma at the pediatric intensive care unit (PICU) is highly heterogeneous. However, current treatment is still based on a 'one-size-fits-all approach'.

AREAS COVERED

We aim to give a comprehensive description of the clinical characteristics of pediatric patients with severe acute asthma admitted to the PICU and available immunological biomarkers, providing the first steps toward precision medicine for this patient population. A literature search was performed using PubMed for relevant studies on severe acute (pediatric) asthma.

EXPERT OPINION

Omics technologies should be used to investigate the relationship between cellular molecules and pathways, and their clinical phenotypes. Inflammatory phenotypes might guide bedside decisions regarding the use of corticosteroids, neutrophil modifiers and/or type of beta-agonist. A next step toward precision medicine should be inclusion of these patients in clinical trials on biologics.

Development of childhood asthma prediction models using machine learning approaches

BACKGROUND

Respiratory symptoms are common in early life and often transient. It is difficult to identify in which children these will persist and result in asthma. Machine learning (ML) approaches have the potential for better predictive performance and generalisability over existing childhood asthma prediction models. This study applied ML approaches to predict school-age asthma (age 10) in early life (Childhood Asthma Prediction in Early life, CAPE model) and at preschool age (Childhood Asthma Prediction at Preschool age, CAPP model).

METHODS

Clinical and environmental exposure data was collected from children enrolled in the Isle of Wight Birth Cohort (N = 1368, ∼15% asthma prevalence). Recursive Feature Elimination (RFE) identified an optimal subset of features predictive of school-age asthma for each model. Seven state-of-the-art ML classification algorithms were used to develop prognostic models. Training was performed by applying fivefold cross-validation, imputation, and resampling. Predictive performance was evaluated on the test set. Models were further externally validated in the Manchester Asthma and Allergy Study (MAAS) cohort.

RESULTS

RFE identified eight and twelve predictors for the CAPE and CAPP models, respectively. Support Vector Machine (SVM) algorithms provided the best performance for both the CAPE (area under the receiver operating characteristic curve, AUC = 0.71) and CAPP (AUC = 0.82) models. Both models demonstrated good generalisability in MAAS (CAPE 8-year = 0.71, 11-year = 0.71, CAPP 8-year = 0.83, 11-year = 0.79) and excellent sensitivity to predict a subgroup of persistent wheezers.

CONCLUSION

Using ML approaches improved upon the predictive performance of existing regression-based models, with good generalisability and ability to rule in asthma and predict persistent wheeze.

Adenotonsillectomy, bronchoscopy and bronchoalveolar lavage in the management of preschool children with severe asthma: pilot study

PURPOSE

This is a pilot study that describes the feasibility and clinical course of a cohort of preschool children with severe asthma undergoing a combined adenotonillectomy (TA), bronchoscopy (B), and bronchoalveolar lavage (BAL) procedure.

METHODS

A retrospective cohort study of preschool patients with severe asthma who underwent a combined TA-B-BAL procedure between 2012 and 2019. Subjects were treated at a tertiary care asthma clinic and had a diagnosis of preschool asthma according to the Canadian Thoracic Society Guidelines. Data on demographics, clinical characteristics, medication use, virology and microbiology from bronchoalveolar lavage, and asthma control questionnaires were collected. Variables were analyzed using paired t test.

RESULTS

Eighteen preschool subjects (mean age 3.19 ± 1.13 years) with severe asthma were identified through the asthma clinic. Patients treated with standard asthma care and a combined  TA-B-BAL procedure  experienced a decrease in the number of oral steroid courses (p = 0.017), emergency department visits (p = 0.03) and wheezing exacerbations (p = 0.026) following the procedure. Ten patients experienced clinically meaningful improvements in TRACK scores after the procedure (p < 0.001).

CONCLUSION

This pilot study provides early evidence that a combined TA-B-BAL procedure is feasible in preschool children with severe asthma and that the procedure may reduce asthma medication use and hospital visits.

Asthma phenotypes and endotypes in childhood

Asthma is a very heterogeneous disease and since early childhood many classifications have been proposed according to phenotype and endotype. The phenotype includes the clinical features of asthma such as age of onset, triggers, comorbidities, response to treatment and evolution over time. The endotype is more difficult to define, includes the underlying immunopathological mechanisms of the disease and requires reliable biomarkers. A deep knowledge of phenotype and endotype of the patient may guide a tailored therapeutic approach. In this review the main phenotypes and endotypes of asthma acknowledged in children will be discussed.

The Need for Testing-The Exercise Challenge Test to Disentangle Causes of Childhood Exertional Dyspnea

Exertional dyspnea is a common symptom in childhood which can induce avoidance of physical activity, aggravating the original symptom. Common causes of exertional dyspnea are exercise induced bronchoconstriction (EIB), dysfunctional breathing, physical deconditioning and the sensation of dyspnea when reaching the physiological limit. These causes frequently coexist, trigger one another and have overlapping symptoms, which can impede diagnoses and treatment. In the majority of children with exertional dyspnea, EIB is not the cause of symptoms, and in asthmatic children it is often not the only cause. An exercise challenge test (ECT) is a highly specific tool to diagnose EIB and asthma in children. Sensitivity can be increased by simulating real-life environmental circumstances where symptoms occur, such as environmental factors and exercise modality. An ECT reflects daily life symptoms and impairment, and can in an enjoyable way disentangle common causes of exertional dyspnea.

Difficult and Severe Asthma in Children

Asthma is the most frequent chronic inflammatory disease of the lower airways affecting children, and it can still be considered a challenge for pediatricians. Although most asthmatic patients are symptom-free with standard treatments, a small percentage of them suffer from uncontrolled persistent asthma. In these children, a multidisciplinary systematic assessment, including comorbidities, treatment-related issues, environmental exposures, and psychosocial factors is needed. The identification of modifiable factors is important to differentiate children with difficult asthma from those with true severe therapy-resistant asthma. Early intervention on modifiable factors for children with difficult asthma allows for better control of asthma without the need for invasive investigation and further escalation of treatment. Otherwise, addressing a correct diagnosis of true severe therapy-resistant asthma avoids diagnostic and therapeutic delays, allowing patients to benefit from using new and advanced biological therapies.

Differences between patients who achieved asthma control and those who remain uncontrolled after standardized severe asthma care strategy

OBJECTIVE

To assess clinical, functional, and inflammatory patterns of children and adolescents with severe uncontrolled asthma, and investigate the differences between patients who achieved asthma control and those who remain uncontrolled after standardized asthma care strategy.

METHODS

Screening all children and adolescents with asthma from the Pediatric Pulmonology Outpatient Clinic of Unicamp, Brazil, and included those with severe uncontrolled asthma according to GINA guidelines criteria. Patients were assessed at baseline and after by demographic and medication data, questionnaires (Asthma Control Test and Pediatric Asthma Quality of Life Questionnaire), Six-Minute Walk Test, skin prick test, spirometry, induced sputum, and blood collection (total immunoglobulin E and eosinophil count). Cytokine dosage was analyzed in sputum supernatant and serum by Cytometric Bead Array.

RESULTS

Thirty-three patients with severe uncontrolled asthma were included (median age 10.9 [7.00-17.60] years). All patients presented satisfactory adherence to treatment and 50% of them achieved good asthma control after six-month follow-up (p < 0.001). Patients who achieved asthma control reported higher intervals since their last exacerbation episode (p = 0.008) and higher quality of life scores (p < 0.001) as compared to patients who remained uncontrolled. We found no changes in lung function markers, inflammatory biomarkers, or cytokine levels between patients with uncontrolled and controlled asthma.

CONCLUSION

Participation of six months in a structured outpatient clinic for children with severe asthma had a notable improvement in control and quality of life of patients. This demonstrates the importance of a global assessment, focused on peculiarities presented by patients with severe uncontrolled asthma.

Determinants of exercise capacity in children and adolescents with severe therapy-resistant asthma

OBJECTIVE

To evaluate the exercise capacity of children and adolescents with severe therapy resistant asthma (STRA) aiming to identify its main determinants.

METHODS

Cross-sectional study including individuals aged 6-18 years with a diagnosis of STRA. Clinical (age and gender), anthropometric (weight, height and body mass index) and disease control data were collected. Lung function (spirometry), cardiopulmonary exercise testing (CPET) and exercise-induced bronchoconstriction (EIB) test were performed.

RESULTS

Twenty-four patients aged 11.5 ± 2.6 years were included. The mean forced expiratory volume in one second (FEV₁) was 91.3 ± 9.2%. EIB occurred in 54.2% of patients. In CPET, the peak oxygen uptake (VO_2peak) was 34.1 ± 7.8 mL kg^-1 min^-1. A significant correlation between ventilatory reserve and FEV₁ (r = 0.57; p = 0.003) was found. Similarly, there was a significant correlation between CPET and percent of FEV₁ fall in the EIB test for both V_E/VO₂ (r = 0.47; p = 0.02) and V_E/VCO₂ (r = 0.46; p = 0.02). Patients with FEV₁<80% had lower ventilatory reserve (p = 0.009). In addition, resting heart rate correlated with VO_2peak (r=-0.40; p = 0.04), V_E/VO₂ (r = 0.46; p = 0.02) and V_E/VCO₂ (r = 0.48; p = 0.01).

CONCLUSIONS

Exercise capacity is impaired in approximately 30% of children and adolescents with STRA. The results indicate that different aspects of aerobic fitness are influenced by distinct determinants, including lung function and EIB.

An approach to the management of children with problematic severe asthma

Children with poor asthma control despite high levels of prescribed treatment are described as having problematic severe asthma. Most of these children have steroid sensitive disease which improves with adherence to daily inhaled corticosteroids and after having removed modifiable factors like poor inhalation technique, persistent adverse environmental exposures and psychosocial factors. These children are described as having “difficult-to-treat asthma” while children with persistent symptoms despite above-mentioned factors having been addressed are described as having “severe therapy-resistant asthma”. In this review, we will describe the 6-step approach to the diagnosis and management of a child with problematic severe asthma adopted by The Royal Brompton Hospital (London, UK). The role of a multidisciplinary team is crucial for identification and treatment of modifiable factors and comorbidities in order to avoid invasive examinations and useless pharmacological treatments. The current knowledge on add-on therapies will be discussed.

Advances in understanding and reducing the burden of severe asthma in children

Severe asthma in children is rare, accounting for only a small proportion of childhood asthma. After addressing modifiable factors such as adherence to treatment, comorbidities, and adverse exposures, children whose disease is not well controlled on high doses of medication form a heterogeneous group of severe asthma phenotypes. Over the past decade, considerable advances have been made in understanding the pathophysiology of severe therapy-resistant asthma in children. However, asthma attacks and hospital admissions are frequent and mortality is still unacceptably high. Strategies to modify the natural history of asthma, prevent severe exacerbations, and prevent lung function decline are needed. Mechanistic studies have led to the development of several biologics targeting type 2 inflammation. This growing pipeline has the potential to reduce the burden of severe asthma; however, detailed assessment and characterisation of each child with seemingly severe asthma is necessary so that the most effective and appropriate management strategy can be implemented. Risk stratification, remote monitoring, and the integration of multiple data sources could help to tailor management for the individual child with severe asthma.

Prediction models for childhood asthma: A systematic review

BACKGROUND

The inability to objectively diagnose childhood asthma before age five often results in both under-treatment and over-treatment of asthma in preschool children. Prediction tools for estimating a child's risk of developing asthma by school-age could assist physicians in early asthma care for preschool children. This review aimed to systematically identify and critically appraise studies which either developed novel or updated existing prediction models for predicting school-age asthma.

METHODS

Three databases (MEDLINE, Embase and Web of Science Core Collection) were searched up to July 2019 to identify studies utilizing information from children ≤5 years of age to predict asthma in school-age children (6-13 years). Validation studies were evaluated as a secondary objective.

RESULTS

Twenty-four studies describing the development of 26 predictive models published between 2000 and 2019 were identified. Models were either regression-based (n = 21) or utilized machine learning approaches (n = 5). Nine studies conducted validations of six regression-based models. Fifteen (out of 21) models required additional clinical tests. Overall model performance, assessed by area under the receiver operating curve (AUC), ranged between 0.66 and 0.87. Models demonstrated moderate ability to either rule in or rule out asthma development, but not both. Where external validation was performed, models demonstrated modest generalizability (AUC range: 0.62-0.83).

CONCLUSION

Existing prediction models demonstrated moderate predictive performance, often with modest generalizability when independently validated. Limitations of traditional methods have shown to impair predictive accuracy and resolution. Exploration of novel methods such as machine learning approaches may address these limitations for future school-age asthma prediction.

Kids, Difficult Asthma and Fungus

Fungi have many potential roles in paediatric asthma, predominantly by being a source of allergens (severe asthma with fungal sensitization, SAFS), and also directly damaging the epithelial barrier and underlying tissue by releasing proteolytic enzymes (fungal bronchitis). The umbrella term ‘fungal asthma’ is proposed for these manifestations. Allergic bronchopulmonary aspergillosis (ABPA) is not a feature of childhood asthma, for unclear reasons. Diagnostic criteria for SAFS are based on sensitivity to fungal allergen(s) demonstrated either by skin prick test or specific IgE. In children, there are no exclusion criteria on total IgE levels or IgG precipitins because of the rarity of ABPA. Diagnostic criteria for fungal bronchitis are much less well established. Data in adults and children suggest SAFS is associated with worse asthma control and greater susceptibility to asthma attacks than non-sensitized patients. The data on whether anti-fungal therapy is beneficial are conflicting. The pathophysiology of SAFS is unclear, but the epithelial alarmin interleukin-33 is implicated. However, whether individual fungi have different pathobiologies is unclear. There are many unanswered questions needing further research, including how fungi interact with other allergens, bacteria, and viruses, and what optimal therapy should be, including whether anti-neutrophilic strategies, such as macrolides, should be used. Considerable further research is needed to unravel the complex roles of different fungi in severe asthma.

Which Child with Asthma is a Candidate for Biological Therapies?

In asthmatic adults, monoclonals directed against Type 2 airway inflammation have led to major improvements in quality of life, reductions in asthma attacks and less need for oral corticosteroids. The paediatric evidence base has lagged behind. All monoclonals currently available for children are anti-eosinophilic, directed against the T helper (TH2) pathway. However, in children and in low and middle income settings, eosinophils may have important beneficial immunological actions. Furthermore, there is evidence that paediatric severe asthma may not be TH2 driven, phenotypes may be less stable than in adults, and adult biomarkers may be less useful. Children being evaluated for biologicals should undergo a protocolised assessment, because most paediatric asthma can be controlled with low dose inhaled corticosteroid if taken properly and regularly. For those with severe therapy resistant asthma, and refractory asthma which cannot be addressed, the two options if they have TH2 inflammation are omalizumab and mepolizumab. There is good evidence of efficacy for omalizumab, particularly in those with multiple asthma attacks, but only paediatric safety, not efficacy, data for mepolizumab. There is an urgent need for efficacy data in children, as well as data on biomarkers to guide therapy, if the right children are to be treated with these powerful new therapies.

Descurainia sophia Ameliorates Eosinophil Infiltration and Airway Hyperresponsiveness by Reducing Th2 Cytokine Production in Asthmatic Mice

In Chinese medicine, Descurainia sophia is used to treat cough by removing the phlegm in asthma and inflammatory airway disease, but the mechanism is not clear. In this study, we evaluated whether D. sophia water extract (DSWE) can alleviate airway inflammation and airway hyperresponsiveness (AHR) in the lungs of a murine asthma model. Female BALB/c mice were divided into five groups: normal controls, ovalbumin (OVA)-sensitized asthmatic mice, and OVA-sensitized mice treated with DSWE (2, 4, 8 g/day) by intraperitoneal injection. After sacrificing the mice, serum was collected to detect OVA-specific antibodies by ELISA, as well as bronchoalveolar lavage fluid (BALF) to detect cytokine levels. We also detected gene expression and histopathologically evaluated the lungs of asthmatic mice. DSWE reduced AHR, goblet cell hyperplasia, eosinophil infiltration, and collagen aggregation in the lungs of asthmatic mice. DSWE also suppressed the gene expression of Th2-associated cytokines and chemokines in lung tissue and inhibited serum OVA-IgE and Th2-associated cytokine levels in the BALF of OVA-sensitized mice. Our findings suggest that DSWE is a powerful immunomodulator for ameliorated allergic reactions by suppressing Th2 cytokine expression in asthmatic mice.

Azithromycin is the answer in paediatric respiratory medicine, but what was the question?

The first clinical indication of non-antibiotic benefits of macrolides was in the Far East, in adults with diffuse panbronchiolitis. This condition is characterised by chronic airway infection, often with Pseudomonas aeruginosa, airway inflammation, bronchiectasis and a high mortality. Low dose erythromycin, and subsequently other macrolides, led in many cases to complete remission of the condition, and abrogated the neutrophilic airway inflammation characteristic of the disease. This dramatic finding sparked a flurry of interest in the many hundreds of macrolides in nature, especially their anti-inflammatory and immunomodulatory effects. The biggest subsequent trials of azithromycin were in cystic fibrosis, which has obvious similarities to diffuse panbronchiolitis. There were unquestionable improvements in lung function and pulmonary exacerbations, but compared to diffuse panbronchiolitis, the results were disappointing. Case reports, case series and some randomised controlled trials followed in other conditions. Three trials of azithromycin in preschool wheeze gave contradictory results; a trial in pauci-inflammatory adult asthma, and a trial in non-cystic fibrosis bronchiectasis both showed a significant reduction in exacerbations, but none matched the dramatic results in diffuse panbronchiolitis. There is clearly a huge risk of antibacterial resistance if macrolides are used widely and uncritically in the community. In summary, Azithromycin is not the answer to anything in paediatric respiratory medicine; the paediatric respiratory community needs to refocus on the dramatic benefits of macrolides in diffuse panbronchiolitis, use modern - omics technologies to determine the endotypes of inflammatory diseases and discover in nature or synthesise designer macrolides to replicate the diffuse panbronchiolitis results. We must now find out how to do better!

Lung clearance index and steroid response in pediatric severe asthma

INTRODUCTION

Lung clearance index (LCI) is a measure of airway disease that has been shown to be abnormal in asthma. We hypothesized that LCI would be higher (worse) in children with severe therapy-resistant asthma (STRA) compared with difficult asthma (DA) and healthy controls and that LCI would fall in response to parenteral steroids in STRA.

METHODS

Sixty-four children with asthma who were prescribed high-dose asthma therapy (GINA steps 4 or 5) performed LCI and spirometry. Forty-three had STRA and 21 DA. Thirty-nine of forty-three STRA patients attended for a clinically indicated bronchoscopy during which an intramuscular injection of triamcinolone was given. LCI, spirometry, and fractional exhaled nitric oxide (FeNO) were performed on the day of the bronchoscopy and repeated 4 weeks later.

RESULTS

LCI was more abnormal in STRA (median: 7.40, range: 5.58-12.34) than in DA (6.55, 5.77-7.75), P = .0006, and healthy controls (6.53, 5.57-7.35), P = .005. In contrast to the first second forced expired volume (FEV₁ ), LCI improved following systemic steroids; of 20 STRA patients with an abnormal LCI at baseline, 13 improved following triamcinolone. LCI and FeNO responses were concordant.

CONCLUSIONS

There is a subgroup of children with STRA in whom LCI is elevated who improve following parenteral steroids. LCI may be a valuable additional domain in assessing steroid response in pediatric asthma.

Clinical and lung function outcomes in a cohort of children with severe asthma

BACKGROUND

Uncontrolled severe asthma in children is burdensome and challenging to manage. This study aims to describe outcomes in children with uncontrolled severe asthma managed in a nurse-led severe asthma clinic (SAC).

METHODS

This retrospective analysis uses data collected from children referred by a paediatric respiratory specialist to a nurse-led SAC for uncontrolled severe asthma between 2014 and 2019. The pre-clinical assessments included a home visit to assess modifiable factors that could be addressed to improve control. A comprehensive lung function analysis was conducted at each visit. Interventions were personalised and included biologic agents. Statistical analysis was performed using nonparametric, two-tailed Mann-Whitney U-test, the parametric Student's t-test, or analysis of variance (ANOVA) as appropriate.

RESULTS

Twenty-three children with a median age of 12 years were seen once, and 16 were followed up. Compared to a non-asthmatic (NA) and asthmatic (A) age-matched cohort, children with severe asthma (SA) had a lower FEV1, and FVC% predicted before and after bronchodilator inhalation, and a higher mean Lung Clearance Index [LCI] (10.5 [SA] versus 7.3 [NA] versus 7.6 [A], p = 0.003). Almost 80% of children with SA had an abnormal LCI, and 48% had a reduced FEV1% at the first SAC visit. Asthma control and FEV1% predicted significantly improved at a follow-up visit, while LCI remained abnormal in the majority of children (83%).

CONCLUSION

Over time, many children with severe asthma showed improved clinical outcomes and lung function while lung ventilation inhomogeneities persisted. Future appropriately controlled studies are required to determine if a nurse-led multidisciplinary SAC is associated with better outcomes.

Severe asthma in children: therapeutic considerations

PURPOSE OF REVIEW

Children with poor asthma control despite maximal maintenance therapy have problematic severe asthma (PSA). A step-wise approach including objective adherence monitoring and a detailed multidisciplinary team assessment to identify modifiable factors contributing to poor control is needed prior to considering therapy escalation. Pathophysiological phenotyping in those with true severe therapy-resistant asthma (STRA) and the current array of add-on therapies will be discussed.

RECENT FINDINGS

Adherence monitoring using electronic devices has shown that only 20-30% of children with PSA have STRA and need additional therapies. Omalizumab and mepolizumab are licensed for children with STRA aged 6 years and older. Although robust safety and efficacy data, with reduced exacerbations, are available for omalizumab, biomarkers predicting response to treatment are lacking. Paediatric safety data are available for mepolizumab, but efficacy data are unknown for those aged 6-11 years and minimal for those 12 years and older. A sub-group of children with STRA have neutrophilia, but the clinical significance and contribution to disease severity remains uncertain.

SUMMARY

Most children with PSA have steroid sensitive disease which improves with adherence to maintenance inhaled corticosteroids. Add-on therapies are only needed for the minority with STRA. Paediatric efficacy data of novel biologics and biomarkers that identify the optimal add-on for each child are lacking. If we are to progress toward individualized therapy for STRA, pragmatic clinical trials of biologics in accurately phenotyped children are needed.

C1q/TNF-related protein-9 alleviates airway inflammation in asthma

BACKGROUNDS

Asthma is characterized as inflammatory disorder in the respiratory system with increasing tendency. Most of the asthma patients suffered from the disease since childhood. Thus, developing novel therapeutic targets of childhood asthma is necessary. Here, we conducted the present study to investigate the effects of CTRP9 (C1q tumor necrosis factor-related protein 9), a newly identified anti-inflammatory factor, on asthma.

METHODS

Sixty asthmatic children (30 moderate and 30 mild) were recruited. The mRNA level of CTRP9 in peripheral blood mononuclear cells (PBMCs) and protein level of CTRP9 in serum and induced sputum (IS) samples from asthma patients and healthy controls (HCs) were measured by qPCR and ELISA, respectively. The anti-inflammatory effects of CTRP9 was determined in vitro and potential therapeutic effect on asthma was evaluated in mouse model.

RESULTS

The mRNA and protein levels of CTRP9 was significantly down-regulated in asthmatics than HCs. Furthermore, the expression level of CTRP9 was negatively correlated with the expression of TNF-α, IL-1β, and IL-6 in PBMCs. The CTRP9 significantly suppressed the expression of pro-inflammatory factors in PBMCs and sputum cells from asthma patients in vitro. And delivering CTRP9 into mouse model of asthma showed disease alleviation.

CONCLUSION

Our data here indicated that CTRP9 may alleviate airway inflammation and remodeling in asthma.

Interleukin-36 receptor antagonist alleviates airway inflammation in asthma via inhibiting the activation of Interleukin-36 pathway

BACKGROUNDS

Asthma is characterized as an inflammatory disorder in the respiratory system with increasing tendency. Most of the asthma patients suffered from the disease since childhood. Thus, developing novel therapeutic targets of pediatric asthma is necessary. Here, we conducted the present study to investigate the effects of IL-36RN (Interleukin-36 receptor antagonist), a newly identified anti-inflammatory factor, on asthma.

METHODS

Sixty asthmatic children (30 moderate and 30 mild) were recruited. The levels of IL-36RN in peripheral blood mononuclear cells (PBMCs), serum and induced sputum (IS) samples from asthma patients and healthy controls (HCs) were measured by qPCR and ELISA. The anti-inflammatory effects of IL-36RN were determined in vitro and potential therapeutic effect on asthma was evaluated in the mouse model of asthma.

RESULTS

The mRNA and protein levels of IL-36RN were significant down-regulated in asthmatics than HCs. The IL-36RN significantly suppressed the expression of pro-inflammatory factors in PBMCs and sputum cells from asthma patients in vitro. And delivering IL-36RN into the mouse model of asthma showed disease alleviation. Pathway analysis showed that the IL-36RN may alleviate airway inflammation in asthma through suppressing the activation of IL-36 pathway.

CONCLUSION

Our data here indicated that IL-36RN may alleviate airway inflammation in asthma through suppressing the activation of IL-36 pathway.

Severe Asthma in Childhood

Severe asthma is broadly defined as asthma requiring a high level of therapy, usually high doses of inhaled corticosteroids, to bring under control. Children who remain symptomatic despite such treatment are a heterogeneous population, and bear a high burden of disease and require high resource utilization. Children with severe asthma require a comprehensive evaluation, careful consideration of alternative diagnoses and comorbid conditions, assessment of medication adherence and environmental conditions, and frequent disease monitoring.

Update in Pediatric Asthma: Selected Issues

Asthma is a complex condition that affects 14% of the world's children and the approach to management includes both pharmacologic as well as non-pharmacologic strategies including attention to complex socioeconomic status phenomena. After an historical consideration of asthma, allergic and immunologic aspects of asthma in children and adolescents are presented. Concepts of socioeconomic aspects of asthma are considered along with environmental features and complications of asthma disparities. Also reviewed are links of asthma with mental health disorders, sleep disturbances and other comorbidities. A stepwise approach to asthma management is discussed that includes pharmacologic and non-pharmacologic strategies in the pediatric population. The role of immunotherapy and use of various immunomodulators are considered as well.

Pulmonary type-2 innate lymphoid cells in paediatric severe asthma: phenotype and response to steroids

Children with severe therapy-resistant asthma (STRA) have poor control despite maximal treatment, while those with difficult asthma (DA) have poor control from failure to implement basic management, including adherence to therapy. Although recognised as clinically distinct, the airway molecular phenotype, including the role of innate lymphoid cells (ILCs) and their response to steroids in DA and STRA is unknown.Immunophenotyping of sputum and blood ILCs and T-cells from STRA, DA and non-asthmatic controls was undertaken. Leukocytes were analysed longitudinally pre- and post-intramuscular triamcinolone in children with STRA. Cultured ILCs were evaluated to assess steroid responsiveness in vitroAirway eosinophils, type 2 T-helper (Th2) cells and ILC2s were significantly higher in STRA patients compared to DA and disease controls, while IL-17+ lymphoid cells were similar. ILC2s and Th2 cells were significantly reduced in vivo following intramuscular triamcinolone and in vitro with steroids. Furthermore, asthma attacks and symptoms reduced after systemic steroids despite persistence of steroid-resistant IL-17+ cells and eosinophils.Paediatric STRA and DA have distinct airway molecular phenotypes with STRA characterised by elevated type-2 cells. Systemic corticosteroids, but not maintenance inhaled steroids resulted in improved symptom control and exacerbations concomitant with a reduction in functional ILC2s despite persistently elevated IL-17+ lymphoid cells.

Severe asthma in children-a review of definitions, epidemiology, and treatment options in 2019

Severe asthma is a relatively uncommon condition in children but one which causes morbidity, occasionally mortality, and is a challenging condition to manage. There are several definitions of severe asthma, which have a common theme of poor control despite high dose inhaled corticosteroid treatment. Depending on the definition chosen, the prevalence of severe childhood asthma may be up to 5% within populations with asthma. Collectively, there is some evidence that the treatments used in severe asthma are beneficial, but a solid evidence-base is lacking for many treatments and some treatments have recognized side effects. Evidence supporting the use of maintenance oral prednisolone and intramuscular triamcinolone is weak. Response to systemic corticosteroids is heterogeneous and recognizing phenotypes or endotypes may identify those most likely to gain maximal benefit from treatment. For children aged 6 to 11 years, the anti-IgE biologic omalizumab is effective and anti-IL-5 agent (mepolizumab) has recently been licenced in Europe (but not the US). Biologics, which are licenced for >11 year olds include omalizumab, mepolizumab, benralizumab, reslizumab, and dupilumab. There is plenty that the clinician can offer to the child and adolescent with severe asthma in 2019, including nontherapeutic and therapeutic interventions. To manage severe asthma, practitioners from broad specialities must establish and maintain a close therapeutic relationship with patients. Looking beyond 2019, more treatment options will emerge for severe childhood asthma, and clinical teams will need to continue weighing up benefits and harms.

Two Sides of the Same Coin?-Treatment of Chronic Asthma in Children and Adults

Globally, asthma is one of the most common chronic conditions that affect individuals of all ages. When poorly controlled, it negatively impacts patient's ability to enjoy life and work. At the population level, effective use of recommended strategies in children and adults can reduce symptom burden, improve quality of life and significantly reduce the risk of exacerbation, decline of lung function and asthma-related death. Inhaled corticosteroid as the initial maintenance therapy, ideally started within 2 years of symptom onset, is highly effective in both children and adults and across various degrees of asthma severity. If asthma is not controlled, the choice of subsequent add-on therapies differs between children and adults. Evidence supporting pharmacological approach to asthma management, especially for those with more severe disease, is more robust in adults compared to children. This is, in part, due to various challenges in the diagnosis of asthma, in the recruitment into clinical trials and in the lack of objective outcomes in children, especially those in the preschool age group. Nevertheless, where evidence is emerging for younger children, it seems to mirror the observations in adults. Clinicians need to develop strategies to implement guideline-based recommendations while taking into consideration individual variations in asthma clinical phenotypes, pathophysiology and treatment responses at different ages.

Immunomodulation in Pediatric Asthma

Childhood asthma is actually defined as a heterogeneous disease, including different clinical variants and partially sharing similar immune mechanisms. Asthma management is mainly focused on maintaining the control of the disease and reducing the risk of adverse outcomes. Most children achieve good control with standard therapies, such as low doses of inhaled corticosteroids (ICS) and/or one or more controller. These medications are targeted to suppress bronchial inflammation and to restore airway responsiveness. However, they are not disease-modifying and do not specifically target inflammatory pathways of asthma; in addition, they are not significantly effective in patients with severe uncontrolled asthma. The aim of this review is to update knowledge on current and novel therapeutic options targeted to immunomodulate inflammatory pathways underlying pediatric asthma, with particular reference on biologic therapies.

Approaches to Asthma Diagnosis in Children and Adults

Although the hallmark features of asthma include reversible airflow obstruction, airway eosinophilia, and symptoms of recurrent wheeze associated with breathlessness and cough, it is a heterogeneous disease. The extent of the pathophysiological abnormalities are variable between patients. Despite this, until recently, asthma diagnosis had been made very simplistically predominantly from a clinical history and examination, and often a trial of medication such as short acting bronchodilators. The limitations of this approach have become increasingly apparent with evidence of inappropriate over diagnosis, under diagnosis and misdiagnosis. Although there is no gold standard single test to make a diagnosis of asthma, there are several objective tests that can be used to support the diagnosis including physiological measures such as obstructive spirometry associated with bronchodilator reversibility and airway hyperresponsiveness. In addition, non-invasive tests of airway inflammation such as exhaled nitric oxide or peripheral blood eosinophils are important to identify those with an allergic or eosinophilic phenotype. Diagnostic guidelines reflect the importance of using objective tests to support a diagnosis of asthma, however practical application in the clinic may not be straightforward. The focus of this review is to discuss the need to undertake objective tests in all patients to support asthma diagnosis and not just rely on clinical features. The advantages, challenges and limitations of performing tests of lung function and airway inflammation in the clinic, the difficulties related to training and interpretation of results will be explored, and the utility and relevance of diagnostic tests will be compared in adults and children.

Severe Asthma-Perspectives From Adult and Pediatric Pulmonology

Both adults and children with severe asthma represent a small proportion of the asthma population; however, they consume disproportionate resources. For both groups it is important to confirm the diagnosis of severe asthma and ensure that modifiable factors such as adherence have, as far as possible, been addressed. Most children can be controlled on inhaled corticosteroids and long term oral corticosteroid use is rare, in contrast to adults where steroid related morbidity accounts for a large proportion of the costs of severe asthma. Atopic sensitization is very common in children with severe asthma as are other atopic conditions such as allergic rhinitis and hay fever which can impact on asthma control. In adults, the role of allergic driven disease, even in those with co-existent evidence of sensitization, is unclear. There is currently an exciting pipeline of novel biologicals, particularly directed at Type 2 inflammation, which afford the possibility of improved asthma control and reduced treatment side effects for people with asthma. However, not all drugs will work for all patients and accurate phenotyping is essential. In adults the terms T2 high and T2 low asthma have been coined to describe groups of patients based on the presence/absence of eosinophilic inflammation and T-helper 2 (TH₂) cytokines. Bronchoscopic studies in children with severe asthma have demonstrated that these children are predominantly eosinophilic but the cytokine patterns do not fit the T2 high paradigm suggesting other steroid resistant pathways are driving the eosinophilic inflammation. It remains to be seen whether treatments developed for adult severe asthma will be effective in children and which biomarkers will predict response.

Epidemiology of Asthma in Children and Adults

Asthma is a globally significant non-communicable disease with major public health consequences for both children and adults, including high morbidity, and mortality in severe cases. We have summarized the evidence on asthma trends, environmental determinants, and long-term impacts while comparing these epidemiological features across childhood asthma and adult asthma. While asthma incidence and prevalence are higher in children, morbidity, and mortality are higher in adults. Childhood asthma is more common in boys while adult asthma is more common in women, and the reversal of this sex difference in prevalence occurs around puberty suggesting sex hormones may play a role in the etiology of asthma. The global epidemic of asthma that has been observed in both children and adults is still continuing, especially in low to middle income countries, although it has subsided in some developed countries. As a heterogeneous disease, distinct asthma phenotypes, and endotypes need to be adequately characterized to develop more accurate and meaningful definitions for use in research and clinical settings. This may be facilitated by new clustering techniques such as latent class analysis, and computational phenotyping methods are being developed to retrieve information from electronic health records using natural language processing (NLP) algorithms to assist in the early diagnosis of asthma. While some important environmental determinants that trigger asthma are well-established, more work is needed to define the role of environmental exposures in the development of asthma in both children and adults. There is increasing evidence that investigation into possible gene-by-environment and environment-by-environment interactions may help to better uncover the determinants of asthma. Therefore, there is an urgent need to further investigate the interrelationship between environmental and genetic determinants to identify high risk groups and key modifiable exposures. For children, asthma may impair airway development and reduce maximally attained lung function, and these lung function deficits may persist into adulthood without additional progressive loss. Adult asthma may accelerate lung function decline and increase the risk of fixed airflow obstruction, with the effect of early onset asthma being greater than late onset asthma. Therefore, in managing asthma, our focus going forward should be firmly on improving not only short-term symptoms, but also the long-term respiratory and other health outcomes.