Problematic severe asthma: a proposed approach to identifying children who are severely resistant to therapy

Risk factors associated with uncontrolled asthma in children - a systematic review and meta-analysis

OBJECTIVE

We aim to assess the risk factors of uncontrolled asthma in children and adolescents.

METHODS

A systemic search was conducted from electronic databases (PubMed/Medline, Cochrane Library, and Google Scholar) from inception to July 17, 2023. All statistical analyses were conducted in Review Manager 5.4.1. Studies meeting inclusion criteria were selected. A random-effects model was used when heterogeneity was seen to pool the studies, and the result was reported in the odds ratio and the corresponding 95% confidence interval. We also used a narrative approach where it was not feasible to quantitatively assess the outcome.

RESULTS

Ten observational studies were used to conduct this systematic review and meta-analysis. A quantitative analysis of five factors was done. Pooled analysis showed a statistically significant risk of uncontrolled asthma in association with past hypersensitivity reactions (standardized mean difference [SMD] = 1.51 (1.16, 1.98); p = .002; I2 = 84%) and incomplete controller adherence (SMD = 3.15 (1.83, 5.41); p < .0001; I2 = 94%). While non-significant relation was seen in parental asthma (SMD = 1.23 (0.98, 1.55); p = .07; I2 = 15%), oral corticosteroid use (SMD = 0.99 (0.72, 1.36); p = .96; I2 = 81%) and education of caregivers (SMD = 0.99 (0.72, 1.36); p = .96; I2 = 81%). Some other factors were also discussed qualitatively.

CONCLUSION

Our study shows that some significant risk factors might cause uncontrolled asthma in children and adolescents like past hypersensitivity reactions and incomplete controller adherence.

Assessment and management of anxiety and depression in a pediatric high-risk asthma clinic

OBJECTIVE

The aims of this study were to determine the prevalence of positive mental health (MH) screens in a pediatric high-risk asthma (HRA) clinic population, and to determine the success rate of engagement in MH services before and after adding a clinical psychologist to our multidisciplinary clinic.

HYPOTHESIS

We hypothesized that the HRA population would have a higher prevalence of anxiety/depression symptoms than that previously reported for the general pediatric asthma population. We anticipated that the presence of an embedded psychologist in HRA clinic would facilitate successful connection to MH services.

METHODS

Pediatric patients in the HRA clinic were prospectively screened for anxiety and depression using validated screening instruments. Positive scores were referred for MH services. Time to MH service engagement was recorded before and after the addition of a clinical psychologist.

RESULTS

A total of 186 patients were screened; 60% had a positive MH screen. Female sex was associated with higher median scores on both screening tools and higher likelihood of engagement in MH services. After addition of a clinical psychologist, new engagement in MH services increased (20% vs. 80%, p < 0.0001), and median time to engagement decreased (14.5 vs. 0.0 months, p = 0.003).

CONCLUSION

There is a high prevalence of anxiety and depression in this pediatric HRA population. Success of engagement in MH services improved after a clinical psychologist joined our multidisciplinary team, suggesting access to care as a primary barrier to engagement.

Progress in diagnosis and treatment of difficult-to-treat asthma in children

At present, medications containing inhaled corticosteroids (ICS-containing) are the keystones of asthma treatment. The majority of asthmatic children can significantly improve clinical outcomes with little worsening by standardized inhaled glucocorticoid treatment, but there is still a small proportion of children who are unable to achieve good symptom control even after the maximum standardized treatment, known as 'children with difficult-to-treat asthma (DA)'. The high heterogeneity of DA makes therapy challenging and expensive, which poses a serious risk to children's health and makes it extremely difficult for clinical physicians to accurately identify and treat children with DA. This article reviews the definition, evaluation, and treatment of this asthma in order to provide a reference for optimal clinical decision-making.

Allergen extract- and component-based diagnostics in children of the ALLIANCE asthma cohort

BACKGROUND

Current in vitro allergen-specific IgE (sIgE) detection assays measure IgE against allergen extracts or molecules in a single- or multiplex approach. Direct comparisons of the performance of such assays among young children with common presentations of allergic diseases regardless of sensitization status are largely missing.

OBJECTIVES

The aim of this study was a comparison of the analytical and diagnostic performance for common clinical questions of three commonly used technologies which rely upon different laboratory methodologies among children of the All Age Asthma (ALLIANCE) cohort (clinicaltrials.gov: NCT02496468).

METHODS

Sera from 106 paediatric study participants (mean age 4 years) were assessed for the presence of sIgE by means of the ImmunoCAP™ sx1 and fx5 mixes, the ImmunoCAP ISAC™ 112 microarray and a Euroline™ panel.

RESULTS

Total and negative concordance was high (>82%->89%), while positive concordance varied considerably (0%-100%) but was also >50% for the most common sensitizations analysed (house dust mite and birch). All three test systems showed good sensitivity and specificity (AUC consistently > 0.7). However, no significant differences with regard to identifying sIgE sensitizations associated with symptoms in children with suspected pollen- or dust-triggered wheeze or presenting with symptoms of allergic rhinoconjunctivitis or food allergy were detected. Extending the number of allergens did not change the similar performance of the three assay systems.

CONCLUSION AND CLINICAL RELEVANCE

Among young children, the three sIgE assays showed good analytical and diagnostic concordance. Our results caution that the identification of larger numbers of sensitizations by more comprehensive multiplex approaches may not improve the clinical utility of sIgE testing in this age group.

High-resolution targeted bisulfite sequencing reveals blood cell type-specific DNA methylation patterns in IL13 and ORMDL3

BACKGROUND

Methylation of DNA at CpG sites is an epigenetic modification and a potential modifier of disease risk, possibly mediating environmental effects. Currently, DNA methylation is commonly assessed using specific microarrays that sample methylation at a few % of all methylated sites.

METHODS

To understand if significant information on methylation can be added by a more comprehensive analysis of methylation, we set up a quantitative method, bisulfite oligonucleotide-selective sequencing (Bs-OS-seq), and compared the data with microarray-derived methylation data. We assessed methylation at two asthma-associated genes, IL13 and ORMDL3, in blood samples collected from children with and without asthma and fractionated white blood cell types from healthy adult controls.

RESULTS

Our results show that Bs-OS-seq can uncover vast amounts of methylation variation not detected by commonly used array methods. We found that high-density methylation information from even one gene can delineate the main white blood cell lineages.

CONCLUSIONS

We conclude that high-resolution methylation studies can yield clinically important information at selected specific loci missed by array-based methods, with potential implications for future studies of methylation-disease associations.

Rhinitis 2020: A practice parameter update

This comprehensive practice parameter for allergic rhinitis (AR) and nonallergic rhinitis (NAR) provides updated guidance on diagnosis, assessment, selection of monotherapy and combination pharmacologic options, and allergen immunotherapy for AR. Newer information about local AR is reviewed. Cough is emphasized as a common symptom in both AR and NAR. Food allergy testing is not recommended in the routine evaluation of rhinitis. Intranasal corticosteroids (INCS) remain the preferred monotherapy for persistent AR, but additional studies support the additive benefit of combination treatment with INCS and intranasal antihistamines in both AR and NAR. Either intranasal antihistamines or INCS may be offered as first-line monotherapy for NAR. Montelukast should only be used for AR if there has been an inadequate response or intolerance to alternative therapies. Depot parenteral corticosteroids are not recommended for treatment of AR due to potential risks. While intranasal decongestants generally should be limited to short-term use to prevent rebound congestion, in limited circumstances, patients receiving regimens that include an INCS may be offered, in addition, an intranasal decongestant for up to 4 weeks. Neither acupuncture nor herbal products have adequate studies to support their use for AR. Oral decongestants should be avoided during the first trimester of pregnancy. Recommendations for use of subcutaneous and sublingual tablet allergen immunotherapy in AR are provided. Algorithms based on a combination of evidence and expert opinion are provided to guide in the selection of pharmacologic options for intermittent and persistent AR and NAR.

Acute wheeze-specific gene module shows correlation with vitamin D and asthma medication

BACKGROUND

Airway obstruction and wheezing in preschool children with recurrent viral infections are a major clinical problem, and are recognised as a risk factor for the development of chronic asthma. We aimed to analyse whether gene expression profiling provides evidence for pathways that delineate distinct groups of children with wheeze, and in combination with clinical information could contribute to diagnosis and prognosis of disease development.

METHODS

We analysed leukocyte transcriptomes from preschool children (6 months-3 years) at acute wheeze (n=107), and at a revisit 2-3 months later, comparing them to age-matched healthy controls (n=66). RNA-sequencing applying GlobinLock was used. The cases were followed clinically until age 7 years. Differential expression tests, weighted correlation network analysis and logistic regression were applied and correlations to 76 clinical traits evaluated.

FINDINGS

Significant enrichment of genes involved in the innate immune responses was observed in children with wheeze. We identified a unique acute wheeze-specific gene-module, which was associated with vitamin D levels (p<0.005) in infancy, and asthma medication and FEV₁%/FVC (forced expiratory volume in 1 s/forced vital capacity) ratio several years later, at age 7 years (p<0.005). A model that predicts leukotriene receptor antagonist medication at 7 years of age with high accuracy was developed (area under the curve 0.815, 95% CI 0.668-0.962).

INTERPRETATION

Gene expression profiles in blood from preschool wheezers predict asthma symptoms at school age, and therefore serve as biomarkers. The acute wheeze-specific gene module suggests that molecular phenotyping in combination with clinical information already at an early episode of wheeze may help to distinguish children who will outgrow their wheeze from those who will develop chronic asthma.

Higher parental education was associated with better asthma control

Aim

Inhaled corticosteroids have resulted in the improved control of asthma and a reduced need for hospitalisation. This study aimed to examine the prevalence of uncontrolled asthma and factors that affect asthma control.

Methods

The data came from a longitudinal cohort study of children. The parents answered questionnaires from age 6 months to 12 years. The response rate at age 12 years was 76% (3637/4777) and doctor‐diagnosed asthma was reported in 6.4% (n = 233). Asthma control was examined with the Asthma Control Test (ACT), where scores below 20 denote uncontrolled asthma.

Results

Of the children with asthma at age 12 years, 15% had an ACT value below 20, that is uncontrolled asthma. Independent risk factors for uncontrolled asthma were wheeze triggered by exercise (adjusted OR, aOR 5.6; 1.9–16.6), cat at home (aOR 3.5; 1.2–10.0) and current doctor‐diagnosed rhinitis (aOR 2.8; 95% CI 1.1–7.0). A higher education in the parents reduced the risk of uncontrolled asthma (aOR 0.3; 95% CI 0.1–0.8). Only six children (i.e. 2.6%) reported hospitalisation due to asthma during the last year.

Conclusion

Of the children with asthma, 15% had uncontrolled asthma. Higher education in the parents was associated with better asthma control in the children.

Th1 cytokines TNF-α and IFN-γ promote corticosteroid resistance in developing human airway smooth muscle

Corticosteroids (CSs) are commonly used to manage wheezing and asthma in pediatric populations. Although corticosteroids are effective in alleviating airway diseases, some children with more moderate-severe asthma phenotypes show CS resistance and exhibit significant airflow obstruction, persistent inflammation, and more frequent exacerbations. Previous studies have demonstrated that Th1 cytokines, such as TNF-α and IFN-γ, promote CS resistance in adult human airway smooth muscle (ASM). In the present study, using a human fetal ASM cell model, we tested the hypothesis that TNF-α/IFN-γ induces CS resistance. In contrast to TNF-α or IFN-γ alone, the combination of TNF-α/IFN-γ blunted the ability of fluticasone propionate (FP) to reduce expression of the chemokines CCL5 and CXCL10 despite expression of key anti-inflammatory glucocorticoid receptor target genes being largely unaffected by TNF-α/IFN-γ. Expression of the NF-κB subunit p65 and phosphorylation of Stat1 were elevated in cells treated with TNF-α/IFN-γ, an effect that remained in the presence of FP. siRNA knockdown studies demonstrated the effects of TNF-α/IFN-γ on increased p65 are mediated by Stat1, a transcription factor activated by IFN-γ. Expression of TNFAIP3, a negative regulator of NF-κB activity, was not altered by TNF-α/IFN-γ. However, the effects of TNF-α/IFN-γ were partially reduced by overexpression of TNFAIP3 but did not influence p65 expression. Together, these data suggest that IFN-γ augments the effects of TNF-α on chemokines by enhancing expression of key inflammatory pathways in the presence of CS. Interactions between TNF-α- and IFN-γ-mediated pathways may promote inflammation in asthmatic children resistant to CSs.

Airway Autoimmune Inflammatory Response (AAIR) Syndrome: An Asthma-Autoimmune Overlap Disorder?

Asthma encompasses numerous phenotypes that may require alternate approaches to diagnosis and therapy, particularly for patients whose symptoms remain poorly controlled despite escalating treatment. We describe 3 patients with apparent asthma who demonstrated unusual findings on cryobiopsy by flexible bronchoscopy and responded to therapy directed against autoimmune disease.

Pediatric severe asthma: a case series report and perspectives on anti-IgE treatment

Background

The primary goal of asthma management is to achieve disease control for reducing the risk of future exacerbations and progressive loss of lung function. Asthma not responding to treatment may result in significant morbidity. In many children with uncontrolled symptoms, the diagnosis of asthma may be wrong or adherence to treatment may be poor. It is then crucial to distinguish these cases from the truly “severe therapy-resistant” asthmatics by a proper filtering process. Herein we report on four cases diagnosed as difficult asthma, detail the workup that resulted in the ultimate diagnosis, and provide the process that led to the prescription of omalizumab.

Case presentation

All children had been initially referred because of asthma not responding to long-term treatment with high-dose inhaled steroids, long-acting β₂-agonists and leukotriene receptor antagonists. Definitive diagnosis was severe asthma. Three out four patients were treated with omalizumab, which improved asthma control and patients’ quality of life. We reviewed the current literature on the diagnostic approach to the disease and on the comorbidities associated with difficult asthma and presented the perspectives on omalizumab treatment in children and adolescents. Based on the evidence from the literature review, we also proposed an algorithm for the diagnosis of pediatric difficult-to-treat and severe asthma.

Conclusions

The management of asthma is becoming much more patient-specific, as more and more is learned about the biology behind the development and progression of asthma. The addition of omalizumab, the first targeted biological treatment approved for asthma, has led to renewed optimism in the management of children and adolescents with atopic severe asthma.

Allergy testing in children with persistent asthma: comparison of four diagnostic methods

BACKGROUND

Multiple allergic sensitizations are common in persistent childhood asthma, and thorough assessment of allergy is crucial for optimal care of these children. Microarray testing offers opportunities for improved sIgE characterization, which has been projected to be useful in the management of multisensitized patients.

OBJECTIVE

The aim of this study was to investigate the accuracy and information obtained by two microarray platforms applied on a well-characterized pediatric asthma cohort.

METHODS

Seventy-one children were recruited from a nationwide Swedish study on severe childhood asthma. Severe (n = 40) and controlled (n = 31) asthmatics were assessed for allergic sensitization by two microarray systems (Microtest and ISAC) and by two standard diagnostic methods (ImmunoCAP and skin prick test). Data on clinical history, physical examination, spirometry, asthma control test, and doctor's diagnosis were collected. Results from the four diagnostic methods were analyzed and compared.

RESULTS

A high prevalence of allergic sensitization was observed in this cohort. The pairwise concordance between two methods was 90-92% independently of methods compared. The sensitivity of the four methods against doctor's diagnosis was 0.77-0.88, and the specificity was 0.97-0.99. Microarray methods provided new information in 47% of the sensitized children in comparison with results obtained by standard diagnostic methods.

CONCLUSION

The high prevalence of food and respiratory sensitization supports the clinical guideline recommendation that allergies should be evaluated in all children with suspected asthma. The microarray platforms studied here demonstrated acceptable accuracy and provided refined IgE characterization in 47% of the patients compared to standard extract-based methods.

Validation of asthma control questionnaire and risk factors affecting uncontrolled asthma among the Lebanese children's population

OBJECTIVES

To validate the Arabic version of the Asthma Control Test (ACT) in asthmatic children in Lebanon and identify risk factors that might affect asthma control in these children.

METHODS

This study, conducted between December 2015 and April 2016, included 300 children.

RESULTS

A high Cronbach's alpha was found for the full scale (0.959). The correlation factors between each item of the ACT scale and the whole scale ranged between 0.710 and 0.775(p < 0.001 for all items). Low mother's educational level as well as the history of asthma in the mother and the father would significantly increase the risk of uncontrolled asthma (p = 0.001; Beta = 1.862; p < 0.001; Beta = 3.534; p < 0.001; Beta = 1.885respectively). Cigarette smoking during breastfeeding and waterpipe smoking by the mother during pregnancy were both significantly associated with uncontrolled asthma (p = 0.005; Beta = 2.105 and p = 0.041; Beta = 2.325 respectively). The high mother's level of education was significantly associated with more asthma control (p = 0.008; Beta = -0.715).

CONCLUSION

The Arabic version of the asthma control questionnaire is a valid tool to use in pediatric patients in the Lebanese population to assess asthma control. Waterpipe smoking during pregnancy and cigarette smoking during breastfeeding, as well as the lower education level are risk factors for uncontrolled asthma. Spreading awareness among health care professionals, as well as reinforcing health education seem to be an important step toward a better asthma control.

Asthma phenotypes in childhood

INTRODUCTION

Asthma is no longer thought of as a single disease, but rather a collection of varying symptoms expressing different disease patterns. One of the ongoing challenges is understanding the underlying pathophysiological mechanisms that may be responsible for the varying responses to treatment. Areas Covered: This review provides an overview of our current understanding of the asthma phenotype concept in childhood and describes key findings from both conventional and data-driven methods. Expert Commentary: With the vast amounts of data generated from cohorts, there is hope that we can elucidate distinct pathophysiological mechanisms, or endotypes. In return, this would lead to better patient stratification and disease management, thereby providing true personalised medicine.

Biomarkers for the Phenotyping and Monitoring of Asthma in Children

An important issue in relation to the utility and reliability of biomarkers for asthma monitoring is how asthma is defined and characterized. What kind of asthma, or at what stage of the disease is a particular biomarker supposed to add information? Often, the purpose, or usefulness of a biomarker is not made clear. Diagnosis, severity evaluation, and monitoring are all different clinical uses for a biomarker, and confusion may arise when a biomarker is suitable for one of these but not another. When the utility of available biomarkers are discussed, these different roles need to be clarified. Our opinion is that there are four aspects of relevance to asthma, for which biomarkers are required: to diagnose allergies, to evaluate inflammation in the airways, to evaluate hyper-responsiveness, and for certain measures of lung function, such as lung clearance index. These types of biomarkers are needed for the phenotyping and monitoring of asthma. Another important role for biomarkers is, as mentioned above, to monitor asthma in order to follow treatment effects on inflammation and hyper-responsiveness as objective adjuncts to the patients' own symptom reports and lung function. This review will mainly focus on biomarkers that reflect airway inflammation. In spite of the numerous studies that have been conducted, we still have to remember that the value of biomarkers available for routine use, such as eosinophil counts in blood and sputum and exhaled nitric oxide, have to be interpreted in relation to reported symptoms and lung function. Measures of bronchial hyper-responsiveness, performed either by direct (methacholine challenge) or indirect (exercise or mannitol challenge) methods, could be considered biomarkers but will not be included in this review. On the other hand, diagnosing allergy is not usually useful for monitoring asthma although it is of fundamental importance for the interpretation of most biomarkers that are suitable for monitoring. We have therefore included the different approaches for diagnosing and evaluating allergic sensitization in this review.

Protein profiles of CCL5, HPGDS, and NPSR1 in plasma reveal association with childhood asthma

Asthma is a common chronic childhood disease with many different phenotypes that need to be identified. We analyzed a broad range of plasma proteins in children with well-characterized asthma phenotypes to identify potential markers of childhood asthma. Using an affinity proteomics approach, plasma levels of 362 proteins covered by antibodies from the Human Protein Atlas were investigated in a total of 154 children with persistent or intermittent asthma and controls. After screening, chemokine ligand 5 (CCL5) hematopoietic prostaglandin D synthase (HPGDS) and neuropeptide S receptor 1 (NPSR1) were selected for further investigation. Significantly lower levels of both CCL5 and HPGDS were found in children with persistent asthma, while NPSR1 was found at higher levels in children with mild intermittent asthma compared to healthy controls. In addition, the protein levels were investigated in another respiratory disease, sarcoidosis, showing significantly higher NPSR1 levels in sera from sarcoidosis patients compared to healthy controls. Immunohistochemical staining of healthy tissues revealed high cytoplasmic expression of HPGDS in mast cells, present in stroma of both airway epithelia, lung as well as in other organs. High expression of NPSR1 was observed in neuroendocrine tissues, while no expression was observed in airway epithelia or lung. In conclusion, we have utilized a broad-scaled affinity proteomics approach to identify three proteins with altered plasma levels in asthmatic children, representing one of the first evaluations of HPGDS and NPSR1 protein levels in plasma.

The cytokine interleukin-26 as a biomarker in pediatric asthma

In this pilot study, we examined associations between local interleukin (IL)-26, disease severity and biomarkers of Th2-mediated inflammation in a well-defined cohort of pediatric patients (14 years median age, 41 % females) with controlled (n = 28) or uncontrolled (n = 48) asthma. Sputum IL-26 protein concentrations (ELISA) reflected disease control in patients without local (low exhaled nitric oxide) or systemic (low blood eosinophils) signs of eosinophilic inflammation. Moreover, sputum-IL-26 concentrations correlated with those of blood neutrophils. Our study indicates that IL-26 is a potential biomarker of disease severity in pediatric asthma without signs of Th2-mediated inflammation.

Severe asthma features in children: a case-control online survey

Background

Very few studies have explored the distinguishing features of severe asthma in childhood in Europe, and only one study was conducted in Southern Europe. The aim of this study was to provide a detailed characterization of children with severe asthma treated in specialized pediatric asthma centers across Italy.

Methods

We conducted a web-based data collection of family, environmental, clinical and laboratory characteristics of 41 patients aged 6–17 years with severe asthma, defined according to the recent guidelines of the European Respiratory Society and the American Thoracic Society, and 78 age-matched peers with non-severe persistent asthma. The patients have been enrolled from 16 hospital-based pediatric pulmonology and allergy centers in Northern, Central, and Southern Italy. Logistic regression analysis assessed the relationship between patients’ characteristics and severe asthma or non-severe persistent asthma.

Results

Features independently and significantly associated with severe asthma included lifetime sensitization to food allergens [Odds ratio (OR), 4.73; 95 % Confidence Interval (CI), 1.21–18.53; p = 0.03], lifetime hospitalization for asthma (OR, 3.71; 95 % CI, 1.11–12.33; p = 0.03), emergency-department visits for asthma during the past year (OR = 11.98; 95 % CI, 2.70–53.11; p = 0.001), and symptoms triggered by physical activity (OR = 12.78; 95 % CI, 2.66–61.40; p = 0.001). Quality-of-life score was worse in patients with severe asthma than in subjects with non-severe persistent asthma (5.9 versus 6.6, p = 0.005). Self-perception of wellbeing was compromised in more than 40 % of patients in both groups. Children with severe asthma had lower spirometric z scores than non-severe asthmatic peers (all p < 0.001), although 56 % of them had a normal forced expiratory volume in 1 s. No differences were found between the two groups for parental education, home environment, patients’ comorbidities, adherence to therapy, exhaled nitric oxide values, and serum eosinophils and IgE .

Conclusions

As expected, children with severe asthma had more severe clinical course and worse lung function than peers with non-severe persistent asthma. Unlike previous reports, we found greater sensitization to food allergens and similar environmental and personal characteristics in patients with severe asthma compared to those with non-severe persistent asthma. Psychological aspects are compromised in a large number of cases and deserve further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13052-016-0217-z) contains supplementary material, which is available to authorized users.

Asthma and Food Allergy in Children: Is There a Connection or Interaction?

This review explores the relationship between food allergy and asthma. They can share the same risk factors, such as parental allergy, atopic eczema, and allergen sensitization, and they often coincide in the same child. Coexistence may negatively influence the severity of both conditions. However, it remains to be determined whether food allergy may directly affect asthma control. An early food sensitization in the first year of life can predict the onset of asthma. Furthermore, asthmatic symptoms could rarely be caused by ingestion or inhalation of the offending food. Asthma caused by food allergy is severe and may be associated with anaphylactic symptoms. Therefore, an accurate identification of the offending foods is necessary in order to avoid exposure. Patients should be instructed to treat asthmatic symptoms quickly and to use self-injectable epinephrine.

Heterogeneity of lower airway inflammation in children with severe-persistent asthma

RATIONALE

The treatment of children with severe-persistent asthma remains problematic. Recent studies suggest that stratification of this cohort by inflammatory type may be useful in designing effective treatment strategies. In this study, we examined the inflammatory profile in bronchoalveolar lavage fluid from children with severe-persistent asthma and compared this profile with serum IgE levels.

METHODS

The inflammatory profile in the bronchoalveolar fluid from 32 children who met criteria for severe-persistent asthma as defined by the Severe Asthma Research Program (SARP) were analyzed retrospectively. Inflammatory patterns were classified as neutrophilic, eosinophilic, mixed, or pauci-granulocytic. Serum total IgE was measured prior to bronchoscopy and determined by ELISA at each hospital's lab by standard procedures.

RESULTS

The most common pattern of inflammation in this cohort was neutrophilic (37.5%) followed by eosinophilic (28.1%), mixed (21.9%), and pauci-granulocytic (11.1%). The odds ratio of an eosinophilic BAL pattern for patients with an elevated serum IgE was 4.67 (CI 0.78-28, P = 0.12). A correlation between serum IgE levels and BAL eosinophil percentages was present (P = 0.04).

CONCLUSIONS

To our knowledge, ours is one of few studies to systematically investigate the pattern of lower airway inflammation in children with severe-persistent asthma. Our results differ from a recent investigation in children, showing more heterogeneity and a greater proportion of neutrophilic inflammation. Further investigation is required to determine whether specific inflammatory patterns are associated with specific etiologies, and whether individualized therapy is warranted.

Predicting asthma morbidity in children using proposed markers of Th2-type inflammation

BACKGROUND

Assessment of inflammation is becoming a common practice in the clinical work-up of children with persistent asthma. Biomarkers of Th2-mediated inflammation include blood eosinophils (B-Eos), exhaled nitric oxide (FeNO), total serum IgE (S-IgE), and serum periostin. The aim of this study was to investigate the associations between asthma morbidity and increased levels of these biomarkers in pediatric asthma.

METHODS

School-age children (n = 96) with various manifestations of persistent asthma were included in this nationwide Swedish study. The protocol included the asthma control test, Juniper's quality of life questionnaire (QoL), assessment of pulmonary function, bronchial hyperresponsiveness, height-adjusted FeNO, blood sampling for S-IgE, B-Eos, and periostin, and high-resolution computed tomography (HRCT) of the lungs.

RESULTS

Children with both high levels of height-adjusted FeNO and B-Eos were younger (p = 0.001), had more often severe asthma (p = 0.015), were more allergic (p < 0.001), had a reduced asthma control (p = 0.035), reduced QoL (p = 0.035), more exacerbations (p = 0.004), reduced FEV1/FVC (p = 0.001), and increased bronchial hyperresponsiveness (p < 0.001) as well as greater bronchial wall thickening on HRCT (p = 0.022) compared to those with low levels of both biomarkers. Grouping children according to high and low serum periostin levels did not relate to differences in clinical characteristics and biomarkers.

CONCLUSIONS

Assessment of both local and systemic Th2-mediated inflammation by the analysis of easily attainable biomarkers such as exhaled NO and blood eosinophils has a high predictive value for the identification of children with the highest asthma morbidity. Adjusting FeNO values according to the individual child's height increases the clinical usefulness of this biomarker.

Update on the current methods for the diagnosis and treatment of severe childhood asthma

The level of asthma control is the key outcome towards which asthma management is evaluated. The majority of children with asthma can obtain adequate control of symptoms through avoidance of triggering factors and/or with the help of low to moderate doses of current available medications. However, there is still a group of children with poor symptom control despite intensive treatment. The current review will provide an overview of a standardized approach to characterize this heterogeneous group of severely sick children. Factors that attenuate the effect of the prescribed treatment and make asthma difficult to treat are discussed. In addition, the usefulness of current methods of assessing asthma severity, pulmonary function, allergy and airway inflammation is also described. Finally, an overview of therapeutic options for children with severe asthma is provided.

The burden of severe asthma in childhood and adolescence: results from the paediatric U-BIOPRED cohorts

U-BIOPRED aims to characterise paediatric and adult severe asthma using conventional and innovative systems biology approaches. A total of 99 school-age children with severe asthma and 81 preschoolers with severe wheeze were compared with 49 school-age children with mild/moderate asthma and 53 preschoolers with mild/moderate wheeze in a cross-sectional study. Despite high-dose treatment, the severe cohorts had more severe exacerbations compared with the mild/moderate ones (annual medians: school-aged 3.0 versus 1.1, preschool 3.9 versus 1.8; p<0.001). Exhaled tobacco exposure was common in the severe wheeze cohort. Almost all participants in each cohort were atopic and had a normal body mass index. Asthma-related quality of life, as assessed by the Paediatric Asthma Quality of Life Questionnaire (PAQLQ) and the Paediatric Asthma Caregiver's Quality of Life Questionnaire (PACQLQ), was worse in the severe cohorts (mean±se school-age PAQLQ: 4.77±0.15 versus 5.80±0.19; preschool PACQLQ: 4.27±0.18 versus 6.04±0.18; both p≤0.001); however, mild/moderate cohorts also had significant morbidity. Impaired quality of life was associated with poor control and airway obstruction. Otherwise, the severe and mild/moderate cohorts were clinically very similar. Children with severe preschool wheeze or severe asthma are usually atopic and have impaired quality of life that is associated with poor control and airflow limitation: a very different phenotype from adult severe asthma. In-depth phenotyping of these children, integrating clinical data with high-dimensional biomarkers, may help to improve and tailor their clinical management.

Phenotypes of severe asthma among children and adolescents in Brazil: a prospective study

BACKGROUND

The morbidity associated with severe uncontrolled asthma is disproportionately higher in low- and middle-income countries than in high-income countries. The aim of this study was to describe the phenotypic characteristics of difficult-to-treat severe asthma and treatment-resistant severe asthma in a sample of children and adolescents in Brazil.

METHODS

This was a prospective study, conducted between 2010 and 2014, following 61 patients (6-18 years of age) who had been diagnosed with severe uncontrolled asthma. The patients were classified and managed in accordance with the World Health Organization asthma follow-up protocol, which calls for re-evaluations of the diagnosis, level of control (functional and clinical), comorbidities, inhaler technique, and environmental factors, together with adjustment of the treatment to achieve a target level of control. We assessed pulmonary function, measured fractional exhaled nitric oxide, and performed sputum cytology. After the target rate of ≥ 80% adherence to inhaled corticosteroid treatment had been reached and all of the re-evaluations had been performed, the patients incorrectly diagnosed with severe uncontrolled asthma were excluded and the remaining patients were classified as having treatment-resistant or difficult-to-treat severe asthma.

RESULTS

We found that, of the 61 patients evaluated, 10 had been misdiagnosed (i.e., they did not have asthma), 15 had moderate asthma, and 36 had severe uncontrolled asthma. Among those 36 patients, the asthma was classified as treatment-resistant in 20 (55.6%) and as difficult-to-treat in 16 (44.4%). In comparison with the patients with difficult-to-treat severe asthma, those with treatment-resistant severe asthma showed a higher median level of fractional exhaled nitric oxide (40 ppb vs. 12 ppb; P < 0.037) and a lower median forced expiratory volume in one second (61% vs. 87%; P < 0.001).

CONCLUSIONS

Although patients with treatment-resistant severe asthma cannot always be distinguished from those with difficult-to-treat severe asthma on the basis of baseline clinical characteristics, reduced airflow and elevated fractional exhaled nitric oxide are factors that could distinguish the two groups. Patients diagnosed with severe uncontrolled asthma should be re-evaluated on a regular basis, in order to exclude other diagnoses, to reduce exacerbations, and to identify patients with persistent airflow limitation.

Transcriptome analysis of controlled and therapy-resistant childhood asthma reveals distinct gene expression profiles

BACKGROUND

Children with problematic severe asthma have poor disease control despite high doses of inhaled corticosteroids and additional therapy, leading to personal suffering, early deterioration of lung function, and significant consumption of health care resources. If no exacerbating factors, such as smoking or allergies, are found after extensive investigation, these children are given a diagnosis of therapy-resistant (or therapy-refractory) asthma (SA).

OBJECTIVE

We sought to deepen our understanding of childhood SA by analyzing gene expression and modeling the underlying regulatory transcription factor networks in peripheral blood leukocytes.

METHODS

Gene expression was analyzed by using Cap Analysis of Gene Expression in children with SA (n = 13), children with controlled persistent asthma (n = 15), and age-matched healthy control subjects (n = 9). Cap Analysis of Gene Expression sequencing detects the transcription start sites of known and novel mRNAs and noncoding RNAs.

RESULTS

Sample groups could be separated by hierarchical clustering on 1305 differentially expressed transcription start sites, including 816 known genes and several novel transcripts. Ten of 13 tested novel transcripts were validated by means of RT-PCR and Sanger sequencing. Expression of RAR-related orphan receptor A (RORA), which has been linked to asthma in genome-wide association studies, was significantly upregulated in patients with SA. Gene network modeling revealed decreased glucocorticoid receptor signaling and increased activity of the mitogen-activated protein kinase and Jun kinase cascades in patients with SA.

CONCLUSION

Circulating leukocytes from children with controlled asthma and those with SA have distinct gene expression profiles, demonstrating the possible development of specific molecular biomarkers and supporting the need for novel therapeutic approaches.

Risk of childhood asthma is associated with CpG-site polymorphisms, regional DNA methylation and mRNA levels at the GSDMB/ORMDL3 locus

Single-nucleotide polymorphisms (SNPs) in GSDMB (Gasdermin B) and ORMDL3 (ORMDL sphingolipid biosynthesis regulator 3) are strongly associated with childhood asthma, but the molecular alterations contributing to disease remain unknown. We investigated the effects of asthma-associated SNPs on DNA methylation and mRNA levels of GSDMB and ORMDL3. Genetic association between GSDMB/ORMDL3 and physician-diagnosed childhood asthma was confirmed in the Swedish birth-cohort BAMSE. CpG-site SNPs (rs7216389 and rs4065275) showed differences in DNA methylation depending on carrier status of the risk alleles, and were significantly associated with methylation levels in two CpG sites in the 5′ UTR (untranslated region) of ORMDL3. In the Swedish Search study, we found significant differences in DNA methylation between asthmatics and controls in five CpG sites; after adjusting for lymphocyte and neutrophil cell counts, three remained significant: one in IKZF3 [IKAROS family zinc finger 3 (Aiolos); cg16293631] and two in the CpG island (CGI) of ORMDL3 (cg02305874 and cg16638648). Also, cg16293631 and cg02305874 correlated with mRNA levels of ORMDL3. The association between methylation and asthma was independent of the genotype in rs7216389, rs4065275 and rs12603332. Both SNPs and CpG sites showed significant associations with ORMDL3 mRNA levels. SNPs influenced expression independently of methylation, and the residual association between methylation and expression was not mediated by these SNPs. We found a differentially methylated region in the CGI shore of ORMDL3 with six CpG sites less methylated in CD8⁺ T-cells. In summary, this study supports that there are differences in DNA methylation at this locus between asthmatics and controls; and both SNPs and CpG sites are independently associated with ORMDL3 expression.

Management of severe asthma in childhood--state of the art and novel perspectives

The majority of children with asthma have mild or moderate disease and can obtain adequate control of symptoms through avoidance of triggering factors and/or with the help of medications. There is still a group of children with severe asthma in whom symptom control is poor depending either on identifiable aggravating factors or on true therapy resistance. These children have a poor quality of life and are limited by the severity of their disease. There is a need for a staged approach to the assessment and treatment of this small but vulnerable and resource-consuming group. The current review will provide an overview of a possible standardized approach to characterize this heterogeneous group of severely sick children including some newly developed ways of assessing asthma severity and potentialities of new asthma therapies. Furthermore, the umbrella term 'problematic severe asthma' is described. The term encompasses children whose severe asthma is due to identifiable exacerbating factors, as well as children who are resistant to any conventional therapeutic approach. Characteristics of these two groups of children are described, as are possible biomarkers and current and emerging diagnostic tools for allergy evaluation. Some recent advances and future possibilities for treatment of severe asthma are also presented in this review.

Severe childhood asthma and allergy to furry animals: refined assessment using molecular-based allergy diagnostics

BACKGROUND

Allergy to cats and dogs and polysensitization towards these animals are associated with severe childhood asthma. Molecular-based allergy diagnostics offers new opportunities for improved characterization and has been suggested to be particularly useful in patients with polysensitization and/or severe asthma. The aim was to use extract- and molecular-based allergy diagnostics to compare patterns of IgE sensitization towards aeroallergens in children with problematic severe and controlled asthma.

METHODS

Children with a positive ImmunoCAP towards any furry animal (cat, dog or horse) were recruited from a Nationwide Swedish study on severe childhood asthma. Severe (n = 37, age 13 years) and controlled (n = 28, age 14 years) asthmatics underwent assessment of allergic sensitization by ImmunoCap (kUA /l) and immunosolid-phase allergen chip (ISAC). In addition, Asthma Control Test, spirometry and a methacholine challenge were performed.

RESULTS

Children with severe asthma had lower asthma control (p < 0.001) and FEV1 (p = 0.001) and more bronchial hyper-responsiveness (p = 0.008) in spite of high doses of inhaled steroids (≥800 μg budesonide). Children with severe asthma displayed higher levels of IgE antibodies towards cat (17 vs. 3.9, p = 0.027), dog (3.8 vs. 1.2, p = 0.012) and horse (7.4 vs. 0.7, p = 0.014). Sensitization towards Can f 2 (22% vs. 0%, p = 0.009) and Equ c 1 (51% vs. 25%, p = 0.03) was more common in severe asthma. IgE levels towards Equ c 1 correlated with asthma control (r = -0.41, p = 0.04).

CONCLUSION

Children with severe allergic asthma had higher sIgE levels to cat, dog and horse. Molecular-based allergy diagnostics revealed a more complex molecular spreading of allergen components in children with the most severe disease.

Pulmonary function testing in children and infants

Pulmonary function testing is performed in children and infants with the aim of documenting lung development with age and making diagnoses of lung diseases. In children and infants with an established lung disease, pulmonary function is tested to assess the disease progression and the efficacy of therapy. It is difficult to carry out the measurements in this age group without disturbances, so obtaining results of good quality and reproducibility is challenging. Young children are often uncooperative during the examinations. This is partly related to their young age but also due to the long testing duration and the unpopular equipment. We address a variety of examination techniques for lung function assessment in children and infants in this review. We describe the measuring principles, examination procedures, clinical findings and their interpretation, as well as advantages and limitations of these methods. The comparability between devices and centres as well as the availability of reference values are still considered a challenge in many of these techniques. In recent years, new technologies have emerged allowing the assessment of lung function not only on the global level but also on the regional level. This opens new possibilities for detecting regional lung function heterogeneity that might lead to a better understanding of respiratory pathophysiology in children.

Difficult-to-treat asthma in childhood

Asthma continues to be one of the greatest burdens to healthcare resources throughout the developed world. In most cases, good symptom control can be achieved with low-dose inhaled corticosteroids, and can be cared for in the primary and secondary healthcare systems. However, there is a group in whom control is not achieved despite high-dose inhaled corticosteroids and maximal add-on therapies; these are children with problematic severe asthma that should be referred to a specialist team for further investigation and management. In this review we aimed to provide an evidence-based guide for pediatricians providing care for children with asthma in secondary healthcare settings. The review focuses on a proposed investigation and management strategy for children aged between 6 and 16 years with problematic severe asthma, and is supported as far as possible by evidence from the literature. We first address recent advances in nomenclature and then discuss our proposed course of investigation and management of these children. Distinction of children with true, severe, therapy-resistant asthma from those with asthma that is difficult to treat because of unaddressed underlying modifiable factors is critical and is discussed in detail.

The chitinase-like protein YKL-40: a possible biomarker of inflammation and airway remodeling in severe pediatric asthma

BACKGROUND

Problematic severe childhood asthma includes a subgroup of patients who are resistant to therapy. The specific mechanisms involved are unknown, and novel biomarkers are required to facilitate treatment and diagnosis of therapy-resistant asthma. The chitinase-like protein YKL-40 has been related to asthma and airway remodeling.

OBJECTIVES

To compare serum YKL-40 levels in children with severe, therapy-resistant asthma (n = 34), children with controlled persistent asthma (n = 39), and healthy controls (n = 27), and to investigate correlations with biomarkers of inflammation and airway remodeling.

METHODS

The study protocol included questionnaires, measurement of exhaled nitric oxide in exhaled air, blood sampling for inflammatory biomarkers, and high-resolution computed tomography of the lungs to identify bronchial wall thickening (therapy-resistant only). Serum YKL-40 levels were measured by ELISA, and all asthmatic children were genotyped for a CHI3L1 promoter single nucleotide polymorphism (rs4950928).

RESULTS

Serum YKL-40 levels were significantly higher in children with therapy-resistant asthma than in healthy children (19.2 ng/mL vs 13.8 ng/mL, P = .03). Among children with severe, therapy-resistant asthma, YKL-40 levels correlated with fraction of exhaled nitric oxide in exhaled air (r = 0.48, P = .004), blood neutrophils (r = 0.63, P < .001), and bronchial wall thickening on high-resolution computed tomography (r = 0.45, P = .01). Following adjustment for CHI3L1 genotype, significantly greater levels of YKL-40 were found in children with therapy-resistant asthma than in children with controlled asthma.

CONCLUSIONS

YKL-40 levels are increased in children with severe, therapy-resistant asthma compared to healthy children, and also compared to children with controlled asthma following correction for genotype.

Difficult childhood asthma: management and future

Diagnosis and management of severe asthma implies the definition of different entities, that is, difficult asthma and refractory severe asthma, but also the different phenotypes included in the term refractory severe asthma. A complete evaluation by a physician expert in asthma is necessary, adapted for each child. Identification of mechanisms involved in different phenotypes in refractory severe asthma may improve the therapeutic approach. The quality of care and monitoring of children with severe asthma is as important as the prescription drug, and is also crucial for differentiating between severe asthma and difficult asthma, whereby expertise is required.

Pathophysiology of asthma: lessons from genetic research with particular focus on severe asthma

There is good evidence that both inherited and environmental factors influence the risk of developing asthma. Only recently, large well-designed studies have been undertaken with the power to identify the genetic causes for asthma, and methods developed in parallel with the Human Genome Project, such as gene expression and epigenetic studies, have made large-scale analyses of functional genetics possible. In this review, we discuss the recent findings from genetic and genomic research studies of asthma, particularly severe asthma, and highlight specific genes for which there are multiple lines of evidence for involvement in asthma pathogenesis. Bio-ontologic enrichment analyses of the most recently identified asthma-related genes point to attributes such as 'molecular and signal transducer activity' and 'immune system processes', which indicates the importance of immunoregulation and inflammatory response in the pathogenesis of asthma. Finally, we discuss how genetic and environmental factors jointly influence asthma susceptibility and summarize how the results may increase understanding of the pathophysiology of asthma-related diseases.

U.S. and European severe asthma cohorts: what can they teach us about severe asthma?

Asthma is a global health problem affecting around 300 million patients of all ages and ethnic groups in all countries around the world. In the majority of subjects with persistent, mild-to-moderate asthma (MA), the disease can be relatively well controlled by the use of currently available medications; however, five to ten per cent of patients suffer from a particularly severe disease that is poorly controlled clinically and often refractory to usual treatment. Improved care of severe asthma (SA) is a major unmet medical need and several international consortia aim at improving our understanding of mechanisms in SA. To manage SA better, standardized definitions and concepts of asthma severity, risk and level of control are critical. In the following sections, we present several guidelines approaches and definitions followed by an overview of U.S. (SARP) and European (ENFUMOSA, BIOAIR, U-BIOPRED) SA networks. Key findings regarding SA phenotypes, risk factors and pathophysiology are discussed. International cooperation in the area of respiratory diseases, including SA, across the Atlantic Ocean, will lead to a better understanding of asthma pathology, especially of those severe, not well controlled or difficult-to-treat cases.

High basophil allergen sensitivity (CD-sens) is associated with severe allergic asthma in children

Children with problematic severe asthma (PA) have persistent symptoms and/or severe exacerbations despite treatment with several drugs. Classification of asthma severity is currently based on level of treatment and assessment of asthma control, but objective biomarkers of asthma severity are needed. To investigate the clinical relevance of basophil allergen threshold sensitivity (CD-sens) as a measure of allergen sensitivity in a well-characterized cohort of children with different manifestations of persistent allergic asthma. Cat-allergic children (6-18 yr) with problematic severe asthma (n = 11) according to GINA were compared with eleven age-matched children with controlled, but persistent asthma (CA). The protocol included standardized questionnaires, asthma control test (ACT), spirometry, methacholine challenges, measurement of FE(NO,) IgE, cat IgE and IgG antibodies, and analysis of CD-sens (CD63-expression) by flow cytometry. The 11 cat-allergic children with PA had a significantly lower ACT score (p < 0.001), reduced FEV(1) (p = 0.04), and increased numbers of blood eosinophils (p = 0.03) compared with the 11 children with CA. The former exhibited a higher CD-sens to cat (p = 0.02). No significant differences were detected with respect to FE(NO) (p = 0.17), IgE (p = 0.84), cat IgE (p = 0.12), and the major cat-allergen rFel d 1 (p = 0.30). CD-sens significantly correlated with ACT (p = 0.002, r = -0.63) and FE(NO) (p = 0.01, r = 0.55). No significant differences between PA and CA were found regarding IgG antibodies to rFel d 1. Cat-allergic children with problematic severe asthma have higher sensitivity to cat allergen, as measured by CD-sens, compared with children with controlled asthma. This suggests that CD-sens could be used as an additional marker for identifying children with the most severe allergic asthma.

IgE antibodies to animal-derived lipocalin, kallikrein and secretoglobin are markers of bronchial inflammation in severe childhood asthma

BACKGROUND

Component-resolved allergy diagnostics enables the detection of crossreactive or species-specific allergen components. This study analysed Immunoglobulin E (IgE) profiles to single allergen components in relation to bronchial inflammation in severe childhood asthma.

METHODS

Ninety-five schoolchildren were assessed, 39 with controlled mild-to-moderate asthma and 56 uncontrolled severe asthmatics. Allergen components (n = 111) of food allergens, pollen and perennial aeroallergens were analysed using an immunosolid-phase allergen chip. Blood eosinophils (10(9) × l(-1)), bronchial inflammation (FeNO, ppb), lung function (FEV(1)%) and bronchial hyper-responsiveness (BHR) (dose-response slope of methacholine challenge) were measured.

RESULTS

A specific IgE response to more than three animal-derived components--lipocalin (nMus m 1, rEqu c 1, Fel d 4, rCan f 1, 2), kallikrein (rCan f 5) and secretoglobin (rFel d 1)--was more common among severe asthmatics compared to children with controlled asthma (n = 14 vs n = 3, P = 0.030). These subjects also displayed higher blood eosinophils (0.65 vs 0.39, P = 0.021), higher Fractional exhaled nitric oxide (38 ppb vs 25 ppb, P = 0.021) and increased BHR (112 vs 28, P = 0.002) compared to other severe asthmatics positive to fewer lipocalin/kallikrein/secretoglobin components. Among all sensitized subjects, there were correlations between specific IgE levels for rFel d 4 and nMus m 1 (r = 0.751, P ≤ 0.001) and for rFel d 4 and rEqu c 1 (r = 0.850, P ≤ 0.001).

CONCLUSION

Multi-sensitization towards lipocalin, kallikrein and secretoglobin components is associated with increased bronchial inflammation in severe asthmatics. In addition, crossreactive patterns were observed between different lipocalin components.

The clinical benefit of evaluating health-related quality-of-life in children with problematic severe asthma

AIM

To evaluate health-related quality-of-life (HR-QoL) and the asthma control test (ACT) in children with problematic severe asthma and those with controlled asthma and to identify whether clinical characteristics show correlations with these measurements.

METHODS

This multicentre cross-sectional study included 93 children in total, 54 with problematic severe asthma and 39 age-matched with controlled asthma. Subjects completed the Paediatric Asthma Quality-of-Life Questionnaire as well as a standardized health questionnaire and the ACT. Objective measurements of exhaled nitric oxide, specific sensitization, pulmonary function and bronchial hyper-responsiveness to methacholine were also taken.

RESULTS

HR-QoL was reduced in children with problematic severe asthma (5.4 vs. 6.7, p < 0.001), particularly for girls (5.1 vs. 5.6 for boys, p = 0.02), and their ACT scores were also lower (17 vs. 23, p < 0.001) compared with those of subjects with controlled asthma. A HR-QoL score <6.2 discriminated problematic severe asthma from controlled asthma with 85% sensitivity and 97% specificity, as did the ACT score <20 (79% sensitivity and 94% specificity). Objective measures and other clinical characteristics were weakly associated with HR-QoL or ACT score.

CONCLUSION

Subjective measurements of HR-QoL and asthma control are both equally useful in differentiating children with problematic severe asthma from those with controlled asthma.