Wheeze in preschool age is associated with pulmonary bacterial infection and resolves after antibiotic therapy

Preventing progression of preschool wheezing to asthma: Opportunities for intervention

Recurrent wheezing in preschool children is heterogeneous and results from numerous genetic and environmental risk factors, which result in the same final clinical manifestation of acute episodes of wheezing but have distinct underlying mechanisms. Effective disease-modifying approaches, therefore, need to target the pathways driving the symptoms. We have good evidence to show that targeting airway eosinophilia alone in early-life preschool wheezing and using inhaled corticosteroids is not disease-modifying. Although airway remodelling develops early in preschool wheezing, the challenge is identifying suitable treatments for structural airway changes. There is increasing evidence for the role of lower airway bacterial infection contributing to wheeze episodes, but clinical trials investigating the impact of targeted antibiotic treatment on disease modification are needed. There is also increasing data supporting an association between lower airway neutrophilia and wheezing in a subgroup of preschool children, but direct causation and the role of neutrophil function remain unknown. Finally, there is encouraging preliminary data for the role of inactivated mixed bacterial lysates in children with non-allergic, infection-associated wheeze episodes, but the impact on longer-term outcomes and their mechanism of action is unknown. This review outlines a range of potential novel targets and approaches that may enable secondary prevention of asthma from preschool wheezing. In parallel, the potential for harm when interventions are introduced indiscriminately is highlighted. Some of the challenges that need to be addressed, including trial designs allowing tailored interventions, the need for non-invasive biomarkers for targeted interventions, and ensuring extended and long-term follow-up after intervention, are highlighted.

Time-dependent gene-environment interactions are essential drivers of asthma initiation and persistence

Asthma is a clinical syndrome caused by heterogeneous underlying mechanisms with some of them having a strong genetic component. It is known that up to 82% of atopic asthma has a genetic background with the rest being influenced by environmental factors that cause epigenetic modification(s) of gene expression. The interaction between the gene(s) and the environment has long been regarded as the most likely explanation of asthma initiation and persistence. Lately, much attention has been given to the time frame the interaction occurs since the host response (immune or biological) to environmental triggers, differs at different developmental ages. The integration of the time variant into asthma pathogenesis is appearing to be equally important as the gene(s)-environment interaction. It seems that, all three factors should be present to trigger the asthma initiation and persistence cascade. Herein, we introduce the importance of the time variant in asthma pathogenesis and emphasize the long-term clinical significance of the time-dependent gene-environment interactions in childhood.

Flexible bronchoscopy findings and management impact in children with oropharyngeal dysphagia

INTRODUCTION

Flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) are frequently performed in children with known or suspected aspiration, however, the additive value of FB in conjunction with direct laryngoscopy and rigid bronchoscopy (DLB) has not been previously quantified. This study details the common endoscopic/cytological findings and associated management impact of FB and BAL in pediatric Aerodigestive patients undergoing combined airway evaluation (FB and DLB) for oropharyngeal dysphagia.

MATERIALS AND METHODS

A retrospective chart review was performed in children <3 years of age followed through a large Aerodigestive center undergoing outpatient, combined airway endoscopy for dysphagia. Patient and procedural characteristics, endoscopic and BAL findings, and management metrics were collected and analyzed. A secondary analysis evaluated the association between endoscopic findings and medication changes.

RESULTS

Ninety-one procedures (median patient age, 15 months) were identified. All procedures included both FB and DLB, and just over half (52.7%) included esophagogastroduodenoscopy. Common endoscopic findings included bronchitis (73.6%), adenoidal hypertrophy (31.9%), and tracheomalacia (10.8%). BAL cytology frequently identified neutrophilic inflammation (mean 39.6% neutrophils [interquartile range 6.5%-71%)]. Cultured pathogens commonly included Streptococcus viridans (46.6%), Hemophilus influenzae (36.3%), Moraxella catarrhalis (30.1%), and Streptococcus pneumoniae (25.0%). FB and BAL results contributed to clinical decisions in 65 of 91 (71.4%) patients. Endoscopically-diagnosed bronchitis (odds ratio [OR] 7.27, 95% confidence interval [CI] 2.4-21.99) and tracheomalacia (OR 5.79, 95% CI 1.20-27.85) were significantly associated with increased odds of medication adjustments following FB.

CONCLUSION

In pediatric Aerodigestive patients undergoing combined airway evaluation for oropharyngeal dysphagia, FB and BAL are high-yield and clinically impactful procedures.

Functional immunophenotyping of blood neutrophils identifies novel endotypes of viral response in preschool children with recurrent wheezing

BACKGROUND

Preschool children with recurrent wheezing are heterogeneous, with differing responses to respiratory viral infections. Although neutrophils are crucial for host defense, their function has not been studied in this population.

OBJECTIVE

We performed functional immunophenotyping on isolated blood neutrophils from 52 preschool children with recurrent wheezing (aeroallergen sensitization, n = 16; no sensitization, n = 36).

METHODS

Blood neutrophils were purified and cultured overnight with polyinosinic:polycytidylic acid [poly(I:C)] as a viral analog stimulus. Neutrophils underwent next-generation sequencing with Reactome pathway analysis and were analyzed for cytokine secretion, apoptosis, myeloperoxidase, and extracellular DNA release. CD14+ monocytes were also exposed to neutrophil culture supernatant and analyzed for markers of M1 and M2 activation.

RESULTS

A total of 495 genes, related largely to the innate immune system and neutrophil degranulation, were differently expressed in children with versus without aeroallergen sensitization. Functional experiments identified more neutrophil degranulation and extracellular trap formation (ie, more myeloperoxidase and extracellular DNA) and less neutrophil proinflammatory cytokine secretion in children with aeroallergen sensitization. Neutrophils also shifted CD14+ monocytes to a more anti-inflammatory (ie, M2) phenotype in sensitized children and a more proinflammatory (ie, M1) phenotype in nonsensitized children. Although both groups experienced viral exacerbations, annualized exacerbation rates prompting unscheduled health care were also higher in children without aeroallergen sensitization after enrollment.

CONCLUSIONS

Systemic neutrophil responses to viral infection differ by allergic phenotype and may be less effective in preschool children without allergic inflammation. Further studies of neutrophil function are needed in this population, which often has less favorable therapeutic responses to inhaled corticosteroids and other therapies directed at type 2-high inflammation.

Airway epithelial development and function: A key player in asthma pathogenesis?

Though asthma is a common and relatively easy to diagnose disease, attempts at primary or secondary prevention, and cure, have been disappointing. The widespread use of inhaled steroids has dramatically improved asthma control but has offered nothing in terms of altering long-term outcomes or reversing airway remodeling and impairment in lung function. The inability to cure asthma is unsurprising given our limited understanding of the factors that contribute to disease initiation and persistence. New data have focused on the airway epithelium as a potentially key factor orchestrating the different stages of asthma. In this review we summarize for the clinician the current evidence on the central role of the airway epithelium in asthma pathogenesis and the factors that may alter epithelial integrity and functionality.

Phenotype and endotype based treatment of preschool wheeze

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Demystifying controversies in preschool wheeze

INTRODUCTION

Wheezing disorders in preschool children are common. Current treatment approaches assume all preschool wheezers are the same and will respond to a short course of oral corticosteroids (OCS) during acute attacks and subsequent maintenance inhaled corticosteroids (ICS) to prevent future attacks. But we have increasing evidence showing preschool wheezing disorders are markedly heterogeneous and the response to corticosteroids either during acute attacks or as maintenance therapy can be variable between patients and is determined by disease severity and underlying pathological phenotype.

AREAS COVERED

The aim of this review is to discuss recent evidence which will help to explain a few critical pathophysiological concepts that are often misunderstood, thus helping to demystify the controversies that often surround preschool wheezing disorders and can contribute to ineffective management.

EXPERT OPINION

Preschool wheezing disorders are distinct from school-age allergic asthma. There is little evidence to support the use of oral corticosteroids for acute attacks. A staged approach to confirm the diagnosis, and objective tests to determine the pathological phenotype of preschool wheeze is essential prior to initiating maintenance therapy to control symptoms and prevent attacks in children with recurrent preschool wheeze.

Advances in the pathogenesis and personalised treatment of paediatric asthma

The diversity of pathology of severe paediatric asthma demonstrates that the one-size-fits-all approach characterising many guidelines is inappropriate. The term "asthma" is best used to describe a clinical syndrome of wheeze, chest tightness, breathlessness, and sometimes cough, making no assumptions about underlying pathology. Before personalising treatment, it is essential to make the diagnosis correctly and optimise basic management. Clinicians must determine exactly what type of asthma each child has. We are moving from describing symptom patterns in preschool wheeze to describing multiple underlying phenotypes with implications for targeting treatment. Many new treatment options are available for school age asthma, including biological medicines targeting type 2 inflammation, but a paucity of options are available for non-type 2 disease. The traditional reliever treatment, shortacting β2 agonists, is being replaced by combination inhalers containing inhaled corticosteroids and fast, longacting β2 agonists to treat the underlying inflammation in even mild asthma and reduce the risk of asthma attacks. However, much decision making is still based on adult data extrapolated to children. Better inclusion of children in future research studies is essential, if children are to benefit from these new advances in asthma treatment.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Enigma variations: The multi-faceted problems of pre-school wheeze

Numerous publications on wheezing disorders in children younger than 6 years have appeared in the medical literature over the last decades with the aim of shedding light on the mechanistic pathways (endotypes) and treatment. Nevertheless, there is yet no consensus as to the appropriate way to manage preschool wheeze mainly because of the lack of a clear definition of "preschool asthma" and the paucity of scientific evidence concerning its underlying endotypes. A symptom-based approach is inadequate since the human airway can respond to external stimuli with a limited range of symptoms and signs, including cough and wheeze, and these manifestations represent the final expression of many clinical entities with potentially different pathophysiologies requiring different individualized treatments. Hence, new studies challenge the symptom-based approach and promote the importance of managing the wheezy child based on the "airway phenotype." This will enable the clinician to identify not only the child with a serious underlying pathology (e.g., a structural airway disorder or immunodeficiency) who is in need of prompt and specific treatment but also increase the specificity of treatment for the child with symptoms suggestive of an "asthma" syndrome. In the latter case, focus should be given to the identification of treatable traits. This review summarizes the current understanding in management of preschool wheezing and highlights the unmet need for further research.

Management of Preschool Wheezing: Guideline from the Emilia-Romagna Asthma (ERA) Study Group

Preschool wheezing should be considered an umbrella term for distinctive diseases with different observable and measurable phenotypes. Despite many efforts, there is a large gap in knowledge regarding management of preschool wheezing. In order to fill this lack of knowledge, the aim of these guidelines was to define management of wheezing disorders in preschool children (aged up to 5 years). A multidisciplinary panel of experts of the Emilia-Romagna Region, Italy, addressed twelve different key questions regarding the management of preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes) and systematic reviews have been conducted on PubMed to answer these specific questions, with the aim of formulating recommendations. The GRADE approach has been used for each selected paper, to assess the quality of the evidence and the degree of recommendations. These guidelines represent, in our opinion, the most complete and up-to-date collection of recommendations on preschool wheezing to guide pediatricians in the management of their patients, standardizing approaches. Undoubtedly, more research is needed to find objective biomarkers and understand underlying mechanisms to assess phenotype and endotype and to personalize targeted treatment.

Bacterial composition and colony structure of the lower respiratory tract in infants and children with recurrent wheezing: a case-control study

BACKGROUND

The bacterial load of the human lower respiratory tract is at least several times lower than that of the other parts of the body. This study aimed to identify the bacterial composition and colony structure of the lower respiratory tract in infants and children with recurrent wheezing compared with those of children with a bronchial foreign body and clarify whether the length of wheezing in infants can contribute to differences in the lower respiratory tract's bacterial colony structure.

METHODS

We collected specimens of alveolar lavage fluid from 48 infants and children who underwent fiberoptic bronchoscopy and were divided into groups: A1 (multiple wheezing: wheezing more than three times in < 1 month), A2 (persistent wheezing: > 1 month), and B (bronchial foreign body; control group). We analyzed the bacterial community structure of alveolar lavage fluid using high-throughput sequencing. The richness and diversity of the microbial communities were assessed by α and β diversity analyses.

RESULTS

A total of 6,644 operational taxonomic units (OTUs) were obtained based on the Illumina Nova sequencing platform and clustered according to those that met the 97% identity threshold, followed by species annotation of the OTU sequences. In the annotation results, 2,608 (39.25%) OTUs were annotated at the genus level. At the genus level, Sphingomonas and Phyllobacterium were significantly higher in group A1 than in group B. There were significantly more Phyllobacterium in group A2 than in group B. Prevotella, Neisseria, and Haemophilus were higher in group B than in groups A1 and A2. The differences in the between-group α and β diversity analyses were statistically significant. The microbial diversity in groups A1 and A2 was significantly less than that in group B, but there was no statistical difference in bacterial community diversity between groups A1 and A2.

CONCLUSION

Recurrent wheezing in infants and children is more likely due to alterations in the overall bacterial microecology and disruption of host respiration and immune homeostasis than the effects of a single bacterium.

Bronchoalveolar lavage profiles in uncontrolled wheezy children compared by asthma predictive index

OBJECTIVE

The asthma predictive index (API) predicts later asthma in preschoolers with frequent wheeze. We hypothesized that airway cytology differs between API positive (API+)/negative (API-) children with uncontrolled/recurrent wheezing with dominance of eosinophils in API+ and neutrophils in API- groups respectively. The main objective of this study is to compare bronchoalveolar lavage (BAL) cell profiles in API+/API- children with recurrent wheezing unresponsive to inhaled corticosteroids (ICS).

DESIGN

Retrospective analysis of BAL in 43 children, 3-36 months (median: 14 months) receiving ICS (31 API+, 12 API-). BAL cell differential counts, bacterial/viral cultures, and lipid-laden macrophage percentages were analyzed. Cell counts presented as median (range).

RESULTS

Neutrophil percentages were increased in both groups (API- 16% [1%-76%]; API+ 42% [1%-95%]; p = NS). Cell percentages were similar for lymphocytes (API- 12% [1%-30%]; API+ 7% [1%-37%]), and macrophages (API- 67.5% [12%-97%]; API+ 41% [2%-94%]). Eosinophil percentages were low in both groups (API- 1% [1%-2%]; API+ 1% [1%-11%]). There was no difference in cellular distributions using absolute cell counts comparing API groups. Bacterial cultures were positive in 18 (60%) API+ and 5 (41%) API- patients (p = 0.10).

CONCLUSION

Cell profiles do not differ between API groups in children ≤36 months with recurrent wheezing unresponsive to ICS. Neutrophil percentages and total granulocyte count correlate with positive bacterial cultures independent of API status. Persistent bacterial bronchitis likely plays an important role in the persistence of symptoms unresponsive to ICS therapy regardless of API status with a trend to more positive cultures in API positive children.

Childhood asthma- pathogenesis and phenotypes

In the pathogenesis of asthma in children there is a pivotal role for a type 2 inflammatory response to early life exposures or events. Interactions between infections, atopy, genetic susceptibility, and environmental exposures (such as farmyard environment, air pollution, tobacco smoke exposure) influence the development of wheezing illness and the risk for progression to asthma. The immune system, lung function and the microbiome in gut and airways develop in parallel and dysbiosis of the microbiome may be a critical factor in asthma development. Increased infant weight gain and preterm birth are other risk factors for development of asthma and reduced lung function. The complex interplay between these factors explains the heterogeneity of asthma in children. Subgroups of patients can be identified as phenotypes based on clinical parameters, or endotypes, based on a specific pathophysiological mechanism. Paediatric asthma phenotypes and endotypes may ultimately help to improve diagnosis of asthma, prediction of asthma development and treatment of individual children, based on clinical, temporal, developmental or inflammatory characteristics. Unbiased, data-driven clustering, using a multidimensional or systems biology approach may be needed to better define phenotypes. The present knowledge on inflammatory phenotypes of childhood asthma has now been successfully applied in the treatment with biologicals of children with severe therapy resistant asthma, and it is to be expected that more personalized treatment options may become available.

Recurrent Severe Preschool Wheeze: From Pre-Specified Diagnostic Labels to Underlying Endotypes

Rationale: Preschool wheezing is heterogeneous, but the underlying mechanisms are poorly understood.

Objectives: To investigate lower airway inflammation and infection in preschool children with different clinical diagnoses undergoing elective bronchoscopy and BAL.

Methods: We recruited 136 children aged 1–5 years (105 with recurrent severe wheeze [RSW]; 31 with nonwheezing respiratory disease [NWRD]). Children with RSW were assigned as having episodic viral wheeze (EVW) or multiple-trigger wheeze (MTW). We compared lower airway inflammation and infection in different clinical diagnoses and undertook data-driven analyses to determine clusters of pathophysiological features, and we investigated their relationships with prespecified diagnostic labels.

Measurements and Main Results: Blood eosinophil counts and percentages and allergic sensitization were significantly higher in children with RSW than in children with a NWRD. Blood neutrophil counts and percentages, BAL eosinophil and neutrophil percentages, and positive bacterial culture and virus detection rates were similar between groups. However, pathogen distribution differed significantly, with higher detection of rhinovirus in children with RSW and higher detection of Moraxella in sensitized children with RSW. Children with EVW and children with MTW did not differ in terms of blood or BAL-sample inflammation, or bacteria or virus detection. The Partition around Medoids algorithm revealed four clusters of pathophysiological features: 1) atopic (17.9%), 2) nonatopic with a low infection rate and high use of inhaled corticosteroids (31.3%), 3) nonatopic with a high infection rate (23.1%), and 4) nonatopic with a low infection rate and no use of inhaled corticosteroids (27.6%). Cluster allocation differed significantly between the RSW and NWRD groups (RSW was evenly distributed across clusters, and 60% of the NWRD group was assigned to cluster 4; P < 0.001). There was no difference in cluster membership between the EVW and MTW groups. Cluster 1 was dominated by Moraxella detection (P = 0.04), and cluster 3 was dominated by Haemophilus or Staphylococcus or Streptococcus detection (P = 0.02).

Conclusions: We identified four clusters of severe preschool wheeze, which were distinguished by using sensitization, peripheral eosinophilia, lower airway neutrophilia, and bacteriology.

Factors and mechanisms contributing to the development of preschool wheezing disorders

INTRODUCTION

Half of all children will experience an episode of wheezing by their sixth birthday and acute episodes of wheezing in preschool children account for the majority of all childhood hospital admissions for wheeze. Recurrent preschool wheezing associates with early loss of lung function and a life-long impact on lung health.

AREAS COVERED

We reviewed the literature on PubMed from August 2010-2020 focussing on factors associated with wheeze inception and persistence, paying specific attention to mechanistic studies that have investigated the impact of early life exposures in shaping immune responses in children with underlying susceptibility to wheezing. In particular, the role of early allergen sensitization, respiratory infections, and the impact of the environment on shaping the airway microbiome and resulting immune responses are discussed.

EXPERT OPINION

There is an abundance of associative data showing the role of in utero and postnatal factors influencing wheeze onset and persistence. However, mechanistic and stratified, biomarker-based interventional studies that confirm these associations are now needed if we are to impact the significant healthcare burden resulting from preschool wheezing disorders.

Which Wheezing Preschoolers Should be Treated for Asthma?

Wheezing disorders in children younger than 5 years are common, but lack of clarity remains about which children should be treated to prevent symptoms and acute episodes. The aim of this review was to discuss a practical approach to deciding which children younger than 5 years with asthma should be treated, and if so, with which strategy. The importance of having a clear definition of "asthma" for this age group, determined by a collection of presenting respiratory symptoms, without assumptions about underlying mechanisms is addressed. Subsequent consideration should be given to timing, severity, and frequency of symptoms, together with assessment of objective biomarkers, including aeroallergen sensitization and blood eosinophils, to inform whether or not a preschooler with recurrent wheezing requires treatment. Numerous unanswered questions remain about the optimal management of nonallergic preschool wheezing and asthma, and areas of specific unmet need and future directions for research are highlighted.

Clinical Predictors of Wheezing Among Children Infected With Mycoplasma Pneumoniae

Background: Mycoplasma pneumoniae (MP) not only was a common pathogen of respiratory tract infections, but also could trigger the exacerbation of asthmatic symptoms in children with or without asthma. Objective: This study aimed to identify possible risk factors associated with wheezing among children diagnosed with MP infection. Methods: A retrospective analysis of medical records of children aged 28 days to 18 years old who visited the Shanghai Children's Hospital between January 2019 and January 2020 was carried out, and all children were then classified into three groups: two wheezing groups (with or without MP infection) and a non-wheezing group with MP infection. Information including patient's demographics, clinical features, laboratory data, and radiography findings was extracted from the electronic medical record system. Chest radiographs were reviewed independently by two board-certified, blinded pediatric radiologists. Results: A total of 1,512 patients were included in our study, and 21.9% of them belonged to the wheezing group without MP infection. Among 1,181 patients with MP infection, 295 people (25.0%) suffered from wheezing, and males accounted for 61%. Through the multivariable logistic regression analyses, we found that six variables were positively associated with wheezing attacks in children with MP infection: male gender (likelihood ratio [LR] = 2.124, 95% confidence interval [CI]: 1.478-3.053), history of allergy (LR= 3.301, 95% CI: 2.206-4.941), history of wheezing (LR = 7.808, 95% CI: 5.276-11.557), autumn in reference to summer (LR = 2.414, 95% CI: 1.500-3.885), non-end-point infiltration in reference to consolidation or pleural effusion (LR = 1.982, 95% CI: 1.348-2.914), and infiltration scope (LR = 1.773, 95% CI: 1.293-2.432). However, the model showed that the probability of wheezing after MP infection decreased as age increased (LR = 0.257, 95% CI: 0.196-0.337). Moreover, the area under the curve (AUC) of the regression model was as high as 0.901 (0.847-0.955). Conclusion: The model integrated with factors including gender, age, season, radiological patterns, infiltration scope, and history of allergy performed well in predicting wheezing attack after MP infection in children.

Childhood asthma heterogeneity at the era of precision medicine: Modulating the immune response or the microbiota for the management of asthma attack

Exacerbations are a main characteristic of asthma. In childhood, the risk is increasing with severity. Exacerbations are a strong phenotypic marker, particularly of severe and therapy-resistant asthma. These early-life events may influence the evolution and be involved in lung function decline.

In children, asthma attacks are facilitated by exposure to allergens and pollutants, but are mainly triggered by microbial agents. Multiple studies have assessed immune responses to viruses, and to a lesser extend bacteria, during asthma exacerbation. Research has identified impairment of innate immune responses in children, related to altered pathogen recognition, interferon release, or anti-viral response. Influence of this host-microbiota dialog on the adaptive immune response may be crucial, leading to the development of biased T helper (Th)2 inflammation. These dynamic interactions may impact the presentations of asthma attacks, and have long-term consequences.

The aim of this review is to synthesize studies exploring immune mechanisms impairment against viruses and bacteria promoting asthma attacks in children. The potential influence of the nature of infectious agents and/or preexisting microbiota on the development of exacerbation is also addressed. We then discuss our understanding of how these diverse host-microbiota interactions in children may account for the heterogeneity of endotypes and clinical presentations. Finally, improving the knowledge of the pathophysiological processes induced by infections has led to offer new opportunities for the development of preventive or curative therapeutics for acute asthma. A better definition of asthma endotypes associated with precision medicine might lead to substantial progress in the management of severe childhood asthma.

Respiratory sequelae and quality of life in children one-year after being admitted with a lower respiratory tract infection: A prospective cohort study from a developing country

INTRODUCTION

Respiratory tract infections in children can result in respiratory sequelae. We aimed to determine the prevalence of, and factors associated with persistent respiratory sequelae 1 year after admission for a lower respiratory tract infection (LRTI).

METHODOLOGY

This prospective cohort study involved children 1 month to 5-years-old admitted with an LRTI. Children with asthma were excluded. Patients were reviewed at 1-, 6-, and 12-months post-hospital discharge. The parent cough-specific quality of life, the depression, anxiety, and stress scale questionnaire and cough diary for 1 month, were administered. Outcomes reviewed were number of unscheduled healthcare visits, respiratory symptoms and final respiratory diagnosis at 6 and/or 12 month-review by pediatric pulmonologists.

RESULTS

Three hundred patients with a mean ± SD age of 14 ± 15 months old were recruited. After 1 month, 239 (79.7%) returned: 28.5% (n = 68/239) had sought medical advice and 18% (n = 43/239) had cough at clinic review. Children who received antibiotics in hospital had significantly lower total cough scores (P = .005) as per the cough diary. After 1 year, 26% (n = 78/300) had a respiratory problem, predominantly preschool wheezing phenotype (n = 64/78, 82.1%). Three children had bronchiectasis or bronchiolitis obliterans. The parent cough-specific quality of life (PCQOL) was significantly lower in children with respiratory sequelae (P < .01). In logistic regression, the use of antibiotics in hospitals (adjusted odds ratio, 0.46; P = .005) was associated with reduced risk of respiratory sequelae.

CONCLUSION

In children admitted for LRTI, a quarter had respiratory sequelae, of which preschool wheeze was the commonest. The use of antibiotics was associated with a lower risk of respiratory sequelae.

Question 4: Is there a role for antibiotics in infantile wheeze?

Acute wheezing episodes are frequent in young children and are associated with high morbidity and healthcare utilization. The role of respiratory viruses in triggering acute wheezing is well known. There is also accumulating evidence that airway bacteria, either alone or as part of bacteria-virus interaction, are important determinants of acute asthma exacerbations. Targeting airway bacteria with antibiotics to reduce the severity of acute wheezing episodes and prevent recurrent wheezing among preschool children has been recently evaluated in three randomized, double-blind, placebo-controlled trials. The results of these studies are controversial. An interventional approach with azithromycin in young children during acute wheezing episodes cannot be generically incorporated into clinical practice, due to the potential consequences of widespread use of antibiotics in such a common clinical setting. This intervention may be reserved for children with really severe, recurrent wheezing episodes. Future research should focus on risk factors that facilitate acquisition of bacterial airway infection in young children and better understanding how virus and bacteria interact with each other during wheezing attacks. Identifying objective biomarkers that may direct the treatment to specific groups of children may represent a significant step forward in the clinical approach of acute wheezing.

Advances in the aetiology, management, and prevention of acute asthma attacks in children

Acute attacks of wheeze or asthma are among the most common reasons for paediatric hospital attendance, and the incidence of severe attacks in the UK is among the highest in Europe. Although most attacks are driven by infection, there are important differences in the underlying pathophysiology of asthma and wheeze between preschool and school-aged children. Allergen sensitisation, airway eosinophilia, and type 2 inflammation predominate in older children, whereas phenotypes in preschool children are variable, often including non-atopic episodes driven by neutrophilic infection. Currently, a universal approach is adopted towards management, but there is a need to make objective assessments of airway function, inflammation, and infection, both during the attack and during stable periods, to identify treatable traits and to target therapy if outcomes are to be improved. An assessment of the risk factors that led to the attack and early, focused follow-up are essential to ensure attacks never occur again.

The effects of macrolides in children with reactive airway disease: a systematic review and meta-analysis of randomized controlled trials

Purpose

Childhood reactive airway diseases (RADs) are concerning problems in children’s airways and may be preceded by bronchiolitis and may progress to childhood asthma. The severity of the disease is indicated by deterioration in pulmonary functions, increased usage of rescue medications, and recurrent wheezing episodes. Macrolides have both antimicrobial and anti-inflammatory functions and have been used as adjunctive therapy in childhood RADs.

Patients and methods

We conducted a meta-analysis to evaluate the effect of macrolides in children with RAD. Literature searches were systematically conducted using an electronic database from inception to August 2018. The Cochrane review risk of bias assessment tool was used to assess the quality of each randomized controlled trial.

Results

Sixteen randomized controlled trials comprising 1,415 participants were investigated in this meta-analysis. Children treated with macrolide therapy showed significantly better pulmonary functions in both forced expiratory volume in one second (% predicted) (difference in means=−9.77, 95% CI=−14.18 to −5.35, P<0.001; I²=0%) and forced expiratory flow 25–75 (% predicted) (difference in means=−14.14, 95% CI=−26.11 to −2.18, P=0.02; I²=29.56%). In addition, the short-acting β-agonist usage days and recurrent wheezing risk were significantly lowered in children with macrolide treatment (standardized difference in means=−0.34, 95% CI=−0.59 to −0.09, P=0.007, I²=27.05% and standardized difference in means=−0.53, 95% CI=−0.81 to −0.26, P<0.001, I²=0%, respectively). Furthermore, the growth of Moraxella catarrhalis from nasal swabs was less in children treated with macrolides (odds ratio=0.19, 95% CI=0.11–0.35, P<0.001). Children who took macrolides had a lower risk of adverse events (risk ratio=0.83, 95% CI=0.70–0.98, P=0.024, I²=0%).

Conclusion

This current meta-analysis suggested that adjunctive therapy with macrolides is safe and effective for achieving better outcomes in childhood RAD.

Gut microbiota components are associated with fixed airway obstruction in asthmatic patients living in the tropics

Microbiome composition has been associated to several inflammatory diseases, including asthma. There are few studies exploring the relationships of gut microbiota with airway obstruction pheonotypes in adult asthma, especially those living in the tropics. We sought to evaluate the relationships of gut microbiota with the airway obstruction and other variables of interest in asthmatic patients living in the tropics according to three phenotypes: No Airway Obstruction (NAO), Reversible Airway Obstruction (RAO) or Fixed Airway Obstruction (FAO). We found that Streptococcaceae:Streptococcus and Enterobacteriaceae:Escherichia-Shigella consistently discriminated asthmatic individuals suffering FAO from NAO or RAO, plus Veillonellaceae:Megasphaera when comparing FAO and RAO (p < 0.05; FDR < 0.05). In the FAO, the network showing the genus relations was less complex and interconnected. Several Rumminococcaceae, Lachnospiraceae and Clostridiales were enriched in patients with low specific IgE levels to mites and Ascaris. All patients shared a common exposure framework; control medication usage and smoking habit were uncommon and equally distributed between them. In conclusion, in this tropical asthmatic population, components of human gut microbiota are associated with the presence of a FAO phenotype and lower specific IgE response to mites and Ascaris.

Long-term exposure to low-dose Haemophilus influenzae during allergic airway disease drives a steroid-resistant neutrophilic inflammation and promotes airway remodeling

Growing evidences indicate that bacteria are associated with pathogenesis of neutrophilic asthma. However, the long-term effect of airway bacterial colonization remains unclear. We sought to establish a murine model to simulate the airway inflammation of long-term bacterial colonization, and to assess the effects of bacteria on allergic airway disease (AAD). BALB/c mice were sensitized twice and subsequently challenged with ovalbumin (OVA) and exposed to low-dose Haemophilus influenzae for approximately 2 months. Mice in treatment groups inhaled budesonide for consecutively 6 days in the last week. Airway inflammatory phenotype, immune response, phagocytic capacity, mucus production, airway remodeling and steroid sensitivity were assessed. Long-term exposure to low-dose H. influenzae during AAD did not cause serious infection but only a slightly increased airway inflammation, which resembled the colonization. Inflammatory phenotype was converted from a steroid-sensitive T helper (Th) 2-associated eosinophilic inflammation to a steroid-resistant Th17-associated neutrophilic inflammation. The increased neutrophilic inflammation was accompanied by defects in regulatory T cell (Treg)-associated immunosuppression and macrophage phagocytosis, and finally promoted mucus hypersecretion and airway remodeling. These features resembled those of refractory neutrophilic asthma in humans. These findings indicate that in asthmatic patients, airway bacterial colonization may be a potential therapeutic target. Minimizing the pathogen burden in airway, such as Haemophilus influenzae, may be beneficial.

Role of microbiome in the pathophysiology and disease course of asthma

PURPOSE OF REVIEW

The emergence of next-generation 16S rRNA sequencing techniques has facilitated a more detailed study of the body's microbiota and led to renewed interest in the association between microbial exposure and asthma inception. In this review, we evaluate the evidence that the respiratory tract and intestinal microbiota contribute to asthma pathogenesis and progression.

RECENT FINDINGS

Human studies have revealed associations between the presence of potentially pathogenic bacteria in the respiratory tract in early life and subsequent risk of allergic sensitization and asthma. Similarly, alterations in the intestinal microbiota of neonates have also been shown to precede the development of asthma. Emerging evidence suggests that the lung microbiota is dysregulated in asthma with specific changes in bacterial diversity and community composition according to severity and phenotype. Studies using germ-free mice have been invaluable in moving our understanding from correlation to causation by demonstrating a mechanistic link between the neonatal microbiota and the development of allergic airway inflammation.

SUMMARY

An expanding body of literature supports the hypothesis that early life microbial exposures and bacterial communities within the lung and/or intestine play an important role in shaping early immunological development. Perturbations in the microbiota may promote immune defects associated with the development of asthma and allergic sensitization.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.

[The interactions between microorganisms and the small airways. A paediatric focus]

The spectrum of respiratory viruses is expanding and emerging diseases have been described regularly over the last fifteen years. The origin of these emerging respiratory viruses may be zoonotic (by crossing species barrier, after changes to RNA viruses such as avian influenza virus type A or coronaviruses), or related to the use of new identification techniques (metapneumovirus, bocavirus). The relationship between bronchiolitis and asthma is now better understood thanks to prospective follow up of birth cohorts. The role of rhinovirus has become predominant with respect to respiratory syncytial virus. The identification of predisposing factors immunological, functional, atopic and genetic, for the onset of asthma after rhinovirus infection suggests that viral infection reveals a predisposition rather than itself being a cause of asthma. The role of bacteria in the natural history of asthma is also beginning to be better understood. The results of the COPSAC Danish cohort have shown the frequency of bacterial identification during wheezy episodes before 3 years, and the impact of bacterial colonization at the age of one month on the onset of asthma by age 5 years. The role of bacterial infections in severe asthma in young children is also discussed.

Refractory wheezing in Chinese children under 3 years of age: bronchial inflammation and airway malformation

Background

Wheezing is a common symptom in early childhood. However, refractory wheezing is difficult to treat, and it may thus account for extensive use of medical resources. It is therefore important to improve our understanding of the pathophysiology of refractory childhood wheezing.

Methods

In this descriptive study, we studied 156 children with refractory wheezing using fiberoptic bronchoscopy and bronchoalveolar lavage (BAL), and compared the results with a control group of 46 children with various pulmonary diseases but no wheezing. Etiology and cell classification were analyzed for each BAL sample.

Results

Overall, 21.8 % of children with refractory wheezing had airway malformations including tracheomalacia, airway stenosis, and tracheal bronchus. The incidence of airway malformations increased to 31 % in infants under 12 months of age. A significant increase in neutrophil ratio and decrease in macrophage ratio were observed in BAL from children with refractory wheezing compared with controls. Pathogen infection led to a higher ratio of neutrophils in the wheezing group compared with controls. However, there were no significant differences in neutrophil ratios among children with various pathogen infections. Furthermore, children with refractory wheezing had a high rate of Mycoplasma pneumoniae infection.

Conclusions

Airway malformations might play an important role in children under 3 years of age with refractory wheezing, especially in infants under 12 months of age. Neutrophil-mediated airway inflammation was characteristic of refractory wheezing in children under 3 years of age. In addition, infections such as M. pneumoniae may aggravate airway inflammation and affect refractory wheezing.

Response to pneumococcal polysaccharide vaccine in children with asthma, and children with recurrent respiratory infections, and healthy children

BACKGROUND

To analyse specific immune response to the 23-valent pneumococcal polysaccharide vaccine by measuring pneumococcal antibodies in children with asthma and with respiratory recurrent infection (RRI) as compared to healthy children.

METHODS

The study included 60 children, divided into three groups: 20 with asthma, 20 with RRI, and 20 healthy controls. Post-vaccination specific IgG antibodies against 10 pneumococcal serotypes (S1, S3, S4, S5, S6B, S9V, S14, S18C, S19F, and S23F) contained in the 23-valent pneumococcal polysaccharide vaccine (PPV) were measured. A specific IgG concentration ≥1.3μg/mL was considered a protective response to the vaccine. For statistical analysis, levels of specific IgG antibodies against each of the 10 pneumococcal serotypes were compared across the three groups of children using the x(2) test.

RESULTS

All of the children showed antipneumococcal antibody levels >1.3μg/mL for over 70% of the serotypes, considered within the normal range of response. Average IgG antibody levels and percentages of children protected were statistically comparable among the three groups studied.

CONCLUSION

The asthmatic children without RRI had pneumococcal antibody levels and percentages of serotype-specific protection to PPV comparable to those of healthy children. Asthmatic children with recurrent infections should be evaluated for specific antibody deficiency (SAD). Because asthma patients are at high risk for invasive pneumococcal infections, it would be worthwhile to explore systematic administration of PPV in children over the age of two years who have not received a pneumococcal conjugate vaccine, considering the positive response to PPV reported here.

Airway Microbiota in Severe Asthma and Relationship to Asthma Severity and Phenotypes

BACKGROUND

The lower airways harbor a community of bacterial species which is altered in asthma.

OBJECTIVES

We examined whether the lower airway microbiota were related to measures of asthma severity.

METHODS

We prospectively recruited 26 severe asthma, 18 non-severe asthma and 12 healthy subjects. DNA was extracted from induced sputum and PCR amplification of the V3-V5 region of bacterial 16S rRNA gene was performed.

RESULTS

We obtained 138,218 high quality sequences which were rarefied at 133 sequences/sample. Twenty OTUs had sequences ≥1% of total. There were marked differences in the distribution of Phyla between groups (P = 2.8x10-118). Bacteroidetes and Fusobacteria were reduced in non-severe and severe asthmatic groups. Proteobacteria were more common in non-severe asthmatics compared to controls (OR = 2.26; 95% CI = 1.94-2.64) and Firmicutes were increased in severe asthmatics compared to controls (OR = 2.15; 95%CI = 1.89-2.45). Streptococcal OTUs amongst the Firmicutes were associated with recent onset asthma, rhinosinusitis and sputum eosinophilia.

CONCLUSIONS

Sputum microbiota in severe asthma differs from healthy controls and non-severe asthmatics, and is characterized by the presence of Streptococcus spp with eosinophilia. Whether these organisms are causative for the pathophysiology of asthma remains to be determined.

Biomarkers to predict asthma in wheezing preschool children

Wheezing in preschool children is a very common symptom. An adequate prediction of asthma in these children is difficult and cannot be reliably assessed with conventional clinical tools. The study of potential predictive biomarkers in various media, ranging from invasive sampling (e.g. bronchoscopy) to non-invasive sampling (lung function testing and exhaled breath analysis), was comprehensively reviewed. The evolution in biomarker discovery has resulted in an 'omics' approach, in which hundreds of biomarkers in the field of genomics, proteomics, metabolomics, and 'breath-omics' can be simultaneously studied. First, results on gene expression and exhaled breath profiles in predicting an early asthma diagnosis are promising. However, many hurdles need to be overcome before clinical implementation is possible. To reliably predict asthma in a wheezing child, probably a holistic approach is needed, combining clinical information with blood sampling, lung function tests, and potentially exhaled breath analysis. The further development of predictive, non-invasive biomarkers may eventually improve an early asthma diagnosis in wheezing preschool children and assist clinicians in early treatment decision-making.

Does IL-17 Respond to the Disordered Lung Microbiome and Contribute to the Neutrophilic Phenotype in Asthma?

Th17/IL-17 plays an important role in host defense and hyperimmune responses against pathogenic bacteria accompanied by the recruitment of neutrophils. Th17-associated immune response is also involved in the pathogenesis of asthma, which is known as a noninfectious allergic airway disease and has been shown to be heterogeneous. Th17-associated inflammation usually contributes to the neutrophilic phenotype, which is often characterized by greater severity, airflow obstruction, and steroid resistance. Concurrently, advanced culture-independent molecular techniques have increased our understanding of the lung microbiome and demonstrated that disorders of the lung microbiome, including changes of the total burden, diversity, and community composition, may contribute to severe, treatment-resistant neutrophilic asthma, although the precise mechanism is still unclear. Because Th17/IL-17 plays a role in bacteria-mediated immune responses and is involved in neutrophilic asthma, there may be a link between them. We review the effects of Th17/IL-17 on bacteria and asthma, showing the possibility that Th17/IL-17 may be a key player in neutrophilic asthma which may be characterized as severe or treatment-resistant by responding to the disordered lung microbiome.

Azithromycin for episodes with asthma-like symptoms in young children aged 1-3 years: a randomised, double-blind, placebo-controlled trial

Background

Bacteria and viruses are equally associated with the risk of acute episodes of asthma-like symptoms in young children, suggesting antibiotics as a potential treatment for such episodes. We aimed to assess the effect of azithromycin on the duration of respiratory episodes in young children with recurrent asthma-like symptoms, hypothesising that it reduces the duration of the symptomatic period.

Methods

In this randomised, double-blind, placebo-controlled trial, we recruited children aged 1–3 years, who were diagnosed with recurrent asthma-like symptoms from the Copenhagen Prospective Studies on Asthma in Childhood 2010 cohort; a birth cohort consisting of the general Danish population of Zealand, including Copenhagen. Exclusion criteria were macrolide allergy, heart, liver, neurological, and kidney disease, and, before each treatment, one or more clinical signs of pneumonia (respiratory frequency of ≥50 breaths per min; fever of ≥39°C; C-reactive protein concentration of ≥476·20 nmol/L [≥50 mg/L]). Each episode of asthma-like symptoms lasting at least 3 days was randomly allocated to a 3-day course of azithromycin oral solution of 10 mg/kg per day or placebo after thorough examination by a study physician at the Copenhagen Prospective Studies on Asthma research unit. Each episode was randomly allocated independently of previous treatment from a computer-generated list of random numbers in blocks of ten (generated at the Pharmacy of Glostrup). Investigators and children were masked until the youngest child turned 3 years of age and throughout the data validation and analysis phases. The primary outcome was duration of the respiratory episode after treatment, verified by prospective daily diaries and analysed with Poisson regression. Analyses were per protocol (excluding those without a primary outcome measure or who did not receive treatment). This trial is registered with ClinicalTrials.gov, number NCT01233297.

Findings

Between Nov 17, 2010, and Jan 28, 2014, we randomly allocated 158 asthma-like episodes in 72 children (79 [50%] to azithromycin and 79 [50%] to placebo). The mean duration of the episode after treatment was 3·4 days for children receiving azithromycin compared with 7·7 days for children receiving placebo. Azithromycin caused a significant shortening of the episode of 63·3% (95% CI 56·0–69·3; p<0·0001). The effect size increased with early initiation of treatment, showing a reduction in episode duration of 83% if treatment was initiated before day 6 of the episode compared with 36% if initiated on or after day 6 (p<0·0001). We noted no differences in clinical adverse events between the azithromycin (18 [23%] of 78 episodes included in final analysis) and placebo (24 [30%] of 79) groups (p=0·30), but we did not investigate bacterial resistance patterns after treatment.

Interpretation

Azithromycin reduced the duration of episodes of asthma-like symptoms in young children, suggesting that this drug could have a role in acute management of exacerbations. Further research is needed to disentangle the inflammatory versus antimicrobial aspects of this relation.

Funding

Lundbeck Foundation, Danish Ministry of Health, Danish Council for Strategic Research, Capital Region Research Foundation.

Host-microbe interactions in distal airways: relevance to chronic airway diseases

This article is the summary of a workshop, which took place in November 2013, on the roles of microorganisms in chronic respiratory diseases. Until recently, it was assumed that lower airways were sterile in healthy individuals. However, it has long been acknowledged that microorganisms could be identified in distal airway secretions from patients with various respiratory diseases, including cystic fibrosis (CF) and non-CF bronchiectasis, chronic obstructive pulmonary disease, asthma and other chronic airway diseases (e.g. post-transplantation bronchiolitis obliterans). These microorganisms were sometimes considered as infectious agents that triggered host immune responses and contributed to disease onset and/or progression; alternatively, microorganisms were often considered as colonisers, which were considered unlikely to play roles in disease pathophysiology. These concepts were developed at a time when the identification of microorganisms relied on culture-based methods. Importantly, the majority of microorganisms cannot be cultured using conventional methods, and the use of novel culture-independent methods that rely on the identification of microorganism genomes has revealed that healthy distal airways display a complex flora called the airway microbiota. The present article reviews some aspects of current literature on host–microbe (mostly bacteria and viruses) interactions in healthy and diseased airways, with a special focus on distal airways.

Understanding host–microbe interactions in distal airways may lead to novel therapies for chronic airway diseaseshttp://ow.ly/HfENz

Diagnostic Support for Selected Paediatric Pulmonary Diseases Using Answer-Pattern Recognition in Questionnaires Based on Combined Data Mining Applications--A Monocentric Observational Pilot Study

Background

Clinical symptoms in children with pulmonary diseases are frequently non-specific. Rare diseases such as primary ciliary dyskinesia (PCD), cystic fibrosis (CF) or protracted bacterial bronchitis (PBB) can be easily missed at the general practitioner (GP).

Objective

To develop and test a questionnaire-based and data mining-supported tool providing diagnostic support for selected pulmonary diseases.

Methods

First, interviews with parents of affected children were conducted and analysed. These parental observations during the pre-diagnostic time formed the basis for a new questionnaire addressing the parents’ view on the disease. Secondly, parents with a sick child (e.g. PCD, PBB) answered the questionnaire and a data base was set up. Finally, a computer program consisting of eight different classifiers (support vector machine (SVM), artificial neural network (ANN), fuzzy rule-based, random forest, logistic regression, linear discriminant analysis, naive Bayes and nearest neighbour) and an ensemble classifier was developed and trained to categorise any given new questionnaire and suggest a diagnosis. For estimating the diagnostic accuracy, we applied ten-fold stratified cross validation.

Results

All questionnaires of patients suffering from CF, asthma (AS), PCD, acute bronchitis (AB) and the healthy control group were correctly diagnosed by the fusion algorithm. For the pneumonia (PM) group 19/21 (90.5%) and for the PBB group 17/18 (94.4%) correct diagnoses could be reached. The program detected the correct diagnoses with an overall sensitivity of 98.8%. Receiver operating characteristics (ROC) analyses confirmed the accuracy of this diagnostic tool. Case studies highlighted the applicability of the tool in the daily work of a GP.

Conclusion

For children with symptoms of pulmonary diseases a questionnaire-based diagnostic support tool using data mining techniques exhibited good results in arriving at diagnostic suggestions. In the hands of a doctor, this tool could be of value in arousing awareness for rare pulmonary diseases such as PCD or CF.

Inflammation and infections in asthma

INTRODUCTION

Asthma is driven by an inflammatory response against normally harmless environmental inorganic and organic compounds in the respiratory tract. Immune responses to airborne pathogens such as viruses and bacteria may reduce the allergic responses but are also known to trigger asthma attacks and eventually lead to severe disease condition.

OBJECTIVE

To investigate the role of respiratory pathogens concerning the induction or protection against acute or chronic asthma manifestations.

METHODS

We included 131 articles for the final review according to their relevance with the subject.

RESULTS

There is apparently contradictory interaction of respiratory germs in the airways of asthmatics which may be protective on one angle but deleterious on the other.

CONCLUSION

The relationship between inflammation and remodeling and the pathogenic role of viral and bacterial infection in the airways of asthmatic patients is still highly debatable and incompletely understood.

The relationship between advances in understanding the microbiome and the maturing hygiene hypothesis

Expanding knowledge about an interaction of the bacterial colonization with pathogenic and non-pathogenic bacteria and the human immune system leads to speculation on potential effects on health and disease. Recent advances in sequencing technologies and new bioinformatic possibilities now allow investigating the microbes that colonize the human gut, skin and airways in more detail. In light of the hygiene hypothesis, the impact of the microbial composition of individuals with allergic sensitization and/or atopic diseases, i.e., allergic asthma or atopic eczema, were investigated in several clinical trials. Altered diversity of gut microbiota during infancy as well as colonization with specific pathogenic and apathogenic bacteria has been linked with an elevated risk for allergy. There are ongoing attempts to establish intervention strategies aimed at modifying initial colonization patterns in early life. While results from animal models, in-vitro data and epidemiological studies encourage the concept of a relationship between the microbiome and the development of allergic diseases, the transfer of these findings to intervention strategies still seems to be a major challenge.

Paediatric asthma and pneumococcal vaccination

Asthma is a clinical condition that has only recently been considered a risk factor for the development of pneumococcal infections. In the most recent guidelines concerning the use of pneumococcal vaccines, the Advisory Committee on Immunisation Practices recommends pneumococcal vaccination only when children with asthma aged <71 months are treated with high-dose corticosteroids, whereas the same Committee clearly indicates that asthma (without any definition of severity or treatment) is a reason for systematic pneumococcal vaccination in adults. It is also unclear which pneumococcal vaccine should be used and how to face the problem of booster doses. The main aim of this paper is to describe what is known about the real risk of pneumococcal infections in children with asthma, and discuss the unsolved problems regarding the paediatric use of pneumococcal vaccines. There are few published data regarding pneumococcal colonisation and the burden of pneumococcal disease in asthmatic children and adolescents, and none at all concerning the relationship between paediatric asthma and immune responses to pneumococcal vaccines. Further studies are therefore essential to assure that children and adolescents with asthma receive the best protection against pneumococcal diseases.

Association between Household Income and Asthma Symptoms among Elementary School Children in Seoul

OBJECTIVES

This study examined the association between socioeconomic factors and asthma symptoms.

METHODS

A total of 6,919 elementary school children in Seoul were enrolled in the study. Data were obtained from a web-based questionnaire survey. The questionnaire was based on the International Study of Asthma and Allergies in Childhood core module. The prevalence of wheeze in the past 12 months and severe asthma symptoms were obtained. The potential risk factors for asthma symptoms included household income and the number of siblings. A multiple logistic regression analysis was used to calculate the odds ratios (OR) and 95% confidence interval (CI) for the risk factors of asthma symptoms.

RESULTS

The prevalence of current wheeze (wheeze in the past 12 months) was 5.2%. Household income and asthma symptoms were inversely associated after adjusting for other potential risk factors (p for trend=0.03). This association was modified by the number of siblings. With two or more siblings, the effect of household income on asthma symptoms was not significant. However, low household income was still a significant variable for patients with fewer than two siblings (OR 1.41; 95% CI, 1.09-1.81).

CONCLUSIONS

It appears that childhood asthma disparity is dependent on household income. Therefore, policies to improve childhood health inequities should be emphasized.

RANTES gene polymorphisms and risk of pediatric asthma: A meta-analysis

Numerous studies have evaluated the association between regulated upon activation, normal T cells expressed and secreted (RANTES) gene polymorphisms (-403G/A and -28C/G) and risk of pediatric asthma. However, the results have been inconsistent. A meta-analysis of the association between RANTES gene polymorphisms and pediatric asthma risk was performed in the current study. A search for published literature was conducted in the Google Scholar, PubMed and the CNKI databases (January 2000 to April 2012) and seven studies were retrieved. The associations between RANTES gene polymorphisms and pediatric asthma risk were estimated by pooled odds ratio (OR) and 95% confidence interval (CI) using a fixed- or random-effects model. Meta-analysis results revealed no significant association between the -403G/A polymorphism and risk of pediatric asthma. In the subgroup analysis by ethnicity, no association was identified between the -403G/A polymorphism and pediatric asthma risk in Caucasian and Asian populations. In the -28C/G group, the meta-analysis indicated a significant association between the -28C/G polymorphism and pediatric asthma susceptibility among the total population (recessive model: OR, 1.34; 95% CI, 1.04-1.72). However, when the subgroup analysis was performed by ethnicity, no significant associations were identified in Asians and Europeans. This result suggests that the -28C/G polymorphism may not be associated with pediatric asthma risk, while the observed increase in the risk of pediatric asthma may be due to racial differences. Additional large-scale studies are required to provide conclusive evidence on the effects of RANTES gene polymorphisms on the risk of pediatric asthma.

Pediatric asthma phenotypes

PURPOSE OF REVIEW

There is currently limited ability to identify which infants and young children with recurrent wheezing will ultimately develop persistent asthma. In addition, it is not clear how risk factors influence the development of asthma in later childhood and adulthood. This review will discuss efforts to categorize these children with recurrent wheezing and develop asthma-predictive tools.

RECENT FINDINGS

Transient and persistent wheezing phenotypes have been identified with atopy, reduced lung function, and viral and bacterial respiratory infection as major risk factors for persistence of asthma. Children with severe asthma tend to have greater magnitude of atopy and lower lung function than those with mild-moderate asthma. These phenotypes and risk factors have been described in previous studies and are supported by the recent literature.

SUMMARY

Heterogeneity of wheezing phenotypes may account for different responses to treatment and varied outcomes. Overlap in phenotypes and instability over time also add additional challenges to defining discrete groups of children with specific outcomes. Further studies are needed to determine combinations of variables that may improve phenotype designation with the goal of improving asthma prevention and treatment as well as predicting outcomes and understanding the pathogenesis of asthma.