The role of early life viral bronchiolitis in the inception of asthma

Viral respiratory infections requiring hospitalization in early childhood related to subsequent asthma onset and exacerbation risks

Viral lower respiratory tract infections (LRTIs), including rhinovirus and respiratory syncytial virus during early childhood, have been linked to subsequent asthma. However, the impact of other respiratory viruses remains unclear. We analyzed nationwide Korean data from January 1, 2008, to December 31, 2018, utilizing the national health insurance database. Our study focused on 19 169 meticulously selected children exposed to severe respiratory infections requiring hospitalization with documented viral pathogens, matched with 191 690 unexposed children at a ratio of 1:10 using incidence density sampling. Our findings demonstrate that asthma exacerbation rates were higher among the exposed cohort than the unexposed cohort over a mean follow-up of 7.8 years. We observed elevated risks of asthma exacerbation and newly developed asthma compared to the unexposed cohort. Hospitalization due to rhinovirus, respiratory syncytial virus, influenza, metapneumovirus, and adenovirus was related to increased asthma exacerbations. Notably, we found a stronger association in cases of multiple LRTI hospitalizations. In conclusion, our study shows that early childhood respiratory viral infections are related to subsequent asthma exacerbations and new asthma diagnoses.

A Community-Guided Approach to Bronchiolitis: A Needs Assessment and Illness Perception Study

The factors influencing caregivers' understanding of pediatric respiratory diseases, such as bronchiolitis, can guide patient care and the acceptability of treatment methods within the healthcare system. This study aims to identify illness perceptions and perform a needs assessment among caregivers of children diagnosed with respiratory diseases. This is a prospective, cross-sectional, questionnaire-driven study of a representative sample of caregivers whose children had an acute respiratory illness. The telephone-administered questionnaire was comprised of (1) demographic items; (2) illness perception questionnaire-revised (IPQ-R); and (3) items about personal barriers, the latter 2 of which employed a 5-point Likert response. Cronbach's alpha (α) was used to measure the internal consistency reliability for each item within the IPQ-R. The Pearson 2-tailed correlation coefficient was used to correlate questionnaire items. We included 75 caregivers whose children have been diagnosed with bronchiolitis (51%), reactive airway disease (RAD) (35%), asthma (33%), and wheezing (44%). We found no significance between the child's diagnosis and the site of recruitment. The most important components of the illness perception were illness coherence (α=0.849), psychological attributions (α=0.903), and barriers to diagnosis (α=0.633). Understanding caregivers' perceptions of respiratory diseases will lead to better treatment acceptance. We must clarify the terms used to define bronchiolitis from viral-induced wheezing, RAD, and the first asthma episode in older infants. Identifying caregivers' gaps in knowledge will help establish a cohesive approach to personalized treatment of respiratory diseases in children and their diagnosis.

Azithromycin for acute bronchiolitis and wheezing episodes in children - a systematic review with meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to analyse the efficacy of azithromycin in acute bronchiolitis and wheezing.

METHODS

PubMed, Scopus, and Web of Science databases were searched for randomized controlled trials comparing azithromycin to placebo in children <2 years of age. Main outcomes were progress of acute wheezing episode and recurrence of wheezing. We used random-effects model to calculate mean difference (MD) with 95% confidence interval (CI) or risk ratios (RR) with CI.

RESULTS

We screened 1604 abstracts and included 7 studies. Risk of bias was low in three and had some concerns in four studies. Need for intensive care unit treatment was assessed in four studies (446 children) and the risk difference was 0.0% (CI -2.0 to 2.0; low quality evidence). Hospitalization duration was -0.27 days shorter in the azithromycin group (MD-0.27, CI -0.47 to -0.07; three studies; moderate quality evidence). Azithromycin did not prevent recurrence of wheezing (RR 0.84, CI 0.45-1.56; three studies), hospital readmissions (RR 1.14, CI 0.82-1.60; four studies).

CONCLUSIONS

We found moderate quality evidence that azithromycin may reduce hospitalization duration. Low certainty evidence suggests that azithromycin does not reduce the need for intensive care unit treatment. Furthermore, azithromycin did not prevent wheezing recurrence.

IMPACT

Azithromycin may reduce hospitalization time in acute bronchiolitis and wheezing episodes among children aged less than two. Azithromycin administrated during the acute wheezing period, does not have preventive effect on wheezing recurrence. Azithromycin seemed to have similar adverse event profile than placebo. Future studies with clinically relevant outcomes, and sufficient sample sizes are needed, before implementing azithromycin into clinical use.

Unveiling the complexity of right middle lobe syndrome: a case series highlighting the association with asthma

Introduction and importance

Right middle lobe syndrome (MLS) is a rare lung disorder primarily affecting children with a history of asthma or atopy. It encompasses a range of pathological and clinical conditions, from recurrent collapses of the middle lobe to bronchiectasis. In this study, the authors present a case series featuring four individuals with MLS associated with asthma, aiming to deepen our understanding of this uncommon condition.

Case presentation

Four paediatric patients with right MLS exhibited symptoms of persistent cough, dyspnoea, and recurrent asthma exacerbations. Radiographic evaluations confirmed features consistent with right MLS, and bronchoscopy revealed mucus plugs and oedematous airways obstructing the right middle lobe bronchus. Treatment with bronchodilators, antibiotics, and corticosteroids led to symptom improvement and resolution of atelectasis.

Clinical discussion

MLS is a rare condition characterized by chronic collapse of the right middle lobe and bronchiectasis. It is challenging to diagnose MLS, but computed tomography (CT) scans provide detailed lung images for confirmation. Treatment focuses on addressing the underlying cause, such as infections or mucus obstruction. Lobectomy may be considered in severe cases. This case series emphasizes the need for further research on MLS, as its rarity and characteristics remain unclear.

Conclusion

These cases exhibited obstructive MLS with and without asthma. Accurate diagnosis is challenging, requiring imaging techniques. MLS has clinical implications, particularly in asthma patients. Future studies should focus on understanding the aetiology of non-obstructive MLS.

Contributions of the early-life microbiome to childhood atopy and asthma development

The rapid rise in atopy and asthma in industrialized nations has led to the identification of early life environmental factors that promote these conditions and spurred research into how such exposures may mediate the trajectory to childhood disease development. Over the past decade, the human microbiome has emerged as a key determinant of human health. This is largely due to the increasing appreciation for the myriad of non-mutually exclusive mechanisms by which microbes tune and train host immunity. Microbiomes, particularly those in early life, are shaped by extrinsic and intrinsic factors, including many of the exposures known to influence allergy and asthma risk. This has led to the over-arching hypothesis that such exposures mediate their effect on childhood atopy and asthma by altering the functions and metabolic productivity of microbiomes that shape immune function during this critical developmental period. The capacity to study microbiomes at the genetic and molecular level in humans from the pre-natal period into childhood with well-defined clinical outcomes, offers an unprecedented opportunity to identify early-life and inter-generational determinants of atopy and asthma outcomes. Moreover, such studies provide an integrative microbiome research framework that can be applied to other chronic inflammatory conditions. This review attempts to capture key studies in the field that offer insights into the developmental origins of childhood atopy and asthma, providing novel insights into microbial mediators of maladaptive immunity and chronic inflammatory disease in childhood.

Role of Air Pollution in the Development of Asthma Among Children with a History of Bronchiolitis in Infancy

BACKGROUND

Infants experiencing bronchiolitis are at increased risk for asthma, but few studies have identified modifiable risk factors. We assessed whether early life air pollution influenced child asthma and wheeze at age 4-6 years among children with a history of bronchiolitis in the first postnatal year.

METHODS

Children with caregiver-reported physician-diagnosed bronchiolitis were drawn from ECHO-PATHWAYS, a pooled longitudinal cohort from six US cities. We estimated their air pollution exposure from age 1 to 3 years from validated spatiotemporal models of fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ), and ozone (O 3 ). Caregivers reported children's current wheeze and asthma at age 4-6 years. We used modified Poisson regression to estimate relative risks (RR) and 95% confidence intervals (CI), adjusting for child, maternal, and home environmental factors. We assessed effect modification by child sex and maternal history of asthma with interaction models.

RESULTS

A total of 224 children had caregiver-reported bronchiolitis. Median (interquartile range) 2-year pollutant concentrations were 9.3 (7.8-9.9) µg/m 3 PM 2.5 , 8.5 (6.4-9.9) ppb NO 2 , and 26.6 (25.6-27.7) ppb O 3 . RRs (CI) for current wheeze per 2-ppb higher O 3 were 1.3 (1.0-1.7) and 1.4 (1.1-1.8) for asthma. NO 2 was inversely associated with wheeze and asthma whereas associations with PM 2.5 were null. We observed interactions between NO 2 and PM 2.5 and maternal history of asthma, with lower risks observed among children with a maternal history of asthma.

CONCLUSION

Our results are consistent with the hypothesis that exposure to modest postnatal O 3 concentrations increases the risk of asthma and wheeze among the vulnerable subpopulation of infants experiencing bronchiolitis.

Wheezing-Related Relevant Factors and the Role of Viral Bronchiolitis

Bronchiolitis is a virus-associated infection of the lower respiratory tract exhibiting signs and symptoms of airway obstruction. Respiratory Syncytial Virus (RSV) is responsible in most cases; however, different rhinoviruses have also been implicated. Specific viruses and time until the first infection, severity of the respiratory condition, and atopic status have a determinant role in the recurrence of wheezing and asthma development. Genetics, lung function, atopic condition, the role of microbiota and environment, pollution, and obesity are considered in the present review. Emergency room visits and hospitalizations because of severe wheezing and smoking during pregnancy among others were identified as risk factors for significant morbidity in our population. Approaching determinant conditions like genetics, allergy, antiviral immunity, and environmental exposures such as farm vs. urban and viral virulence provides an opportunity to minimize morbidity of viral illness and asthma in children.

Racial and ethnic disparities in bronchiolitis management in freestanding children's hospitals

OBJECTIVE

Variation in bronchiolitis management by race and ethnicity within emergency departments (EDs) has been described in single-center and prospective studies, but large-scale assessments across EDs and inpatient settings are lacking. Our objective is to describe the association between race and ethnicity and bronchiolitis management across 37 U.S. freestanding children's hospitals from 2015 to 2018.

METHODS

Using the Pediatric Health Information System, we analyzed ED and inpatient visits from November 2015 to November 2018 of children with bronchiolitis 3 to 24 months old. Rates of use for specific diagnostic tests and therapeutic measures were compared across the following race/ethnicity categories: 1) non-Hispanic White (NHW), 2) non-Hispanic Black (NHB), 3) Hispanic, and 4) other. The subanalyses of ED patients only and children < 1 year old were performed. Mixed-effect logistic regression was performed to compare the adjusted odds of receiving specific test/treatment using NHW children as the reference group.

RESULTS

A total of 134,487 patients met inclusion criteria (59% male, 28% NHB, 26% Hispanic). Adjusted analysis showed that NHB children had higher odds of receiving medication associated with asthma (odds ratio [OR] = 1.27, 95% confidence interval [CI] = 1.22 to 1.32) and lower odds of receiving diagnostic tests (blood cultures, complete blood counts, viral testing, chest x-rays; OR = 0.78, 95% CI = 0.75 to 0.81) and antibiotics (OR = 0.58, 95% CI = 0.52 to 0.64) than NHW children. Hispanic children had lower odds of receiving diagnostic testing (OR = 0.94, 95% CI = 0.90 to 0.98), asthma-associated medication (OR = 0.92, 95% CI = 0.88 to 0.96), and antibiotics (OR = 0.74, 95% CI = 0.66 to 0.82) compared to NHW children.

CONCLUSION

NHB children more often receive corticosteroid and bronchodilator therapies; NHW children more often receive antibiotics and chest radiography. Given that current guidelines generally recommend supportive care with limited diagnostic testing and medical intervention, these findings among NHB and NHW children represent differing patterns of overtreatment. The underlying causes of these patterns require further investigation.

The azithromycin to prevent wheezing following severe RSV bronchiolitis-II clinical trial: Rationale, study design, methods, and characteristics of study population

Severe respiratory syncytial virus (RSV) bronchiolitis in early life is a significant risk factor for future recurrent wheeze (RW) and asthma. The goal of the Azithromycin to Prevent Wheezing following severe RSV bronchiolitis II (APW-RSV II) clinical trial is to evaluate if azithromycin treatment in infants hospitalized with RSV bronchiolitis reduces the occurrence of RW during the preschool years. The APW-RSV II clinical trial is a double-blind, placebo-controlled, parallel-group, randomized trial, including otherwise healthy participants, ages 30 days-18 months, who are hospitalized due to RSV bronchiolitis. The study includes an active randomized treatment phase with azithromycin or placebo for 2 weeks, and an observational phase of 18-48 months. Two hundred participants were enrolled during three consecutive RSV seasons beginning in the fall of 2016 and were randomized to receive oral azithromycin 10 mg/kg/day for 7 days followed by 5 mg/kg/day for an additional 7 days, or matched placebo. The study hypothesis is that in infants hospitalized with RSV bronchiolitis, the addition of azithromycin therapy to routine bronchiolitis care would reduce the likelihood of developing post-RSV recurrent wheeze (≥3 episodes). The primary clinical outcome is the occurrence of a third episode of wheezing, which is evaluated every other month by phone questionnaires and during yearly in-person visits. A secondary objective of the APW-RSV II clinical trial is to examine how azithromycin therapy changes the upper airway microbiome composition, and to determine if these changes are related to the occurrence of post-RSV RW. Microbiome composition is characterized in nasal wash samples obtained before and after the study treatments. This clinical trial may identify the first effective intervention applied during severe RSV bronchiolitis to reduce the risk of post-RSV RW and ultimately asthma.

Gestational hypertension and childhood atopy: a Millennium Cohort Study analysis

Gestational hypertension may confer risk of atopic disease in offspring through a direct biological mechanism, but another possibility is that risk is mediated through complications of pregnancy. To explore these associations, we conducted an analysis of a nationally representative birth cohort based in the UK involving children born 2000-2002. We included 12,450 mother-child pairs. We used logistic regression to estimate the association between hypertensive disease and asthma, hay fever, or eczema by age 5, and parentally reported early wheeze and severe wheeze. Mediation by gestation at delivery and caesarean delivery was explored using causal mediation analysis. Odds ratios (95% CI) for gestational hypertension and childhood asthma, hay fever, and eczema were 1.32 (1.09, 1.59), 1.22 (0.97, 1.55), and 1.12 (0.96, 1.32) respectively, adjusted for confounding. The population attributable fractions were 2.4% (1.0-3.8%), 0.9% (-0.3% to 2.1%), and 1.8% (0.0-3.7%), respectively. Accounting for mediation by gestational age and caesarean delivery, odds ratios (95% CI) for the potential direct effects of gestational hypertension were 1.21 (0.97, 1.50), 1.17 (0.91, 1.49), and 1.11 (0.94, 1.31) for the same.Conclusion: Gestational hypertension was weakly positively associated with asthma and this was partly mediated by earlier delivery. Only a small proportion of early childhood asthma was attributable to gestational hypertensive disease in this representative UK-based birth cohort. What is known: • Gestational hypertension has been shown to be an inconsistent risk factor for the atopic diseases. • The in utero immune environment may modify the risk of atopy in offspring; alternatively, complications of pregnancy including caesarean delivery and prematurity may explain an association between hypertensive disease and atopy. What is new: • Self-reported gestational hypertension was a weak risk factor for asthma and wheeze in the Millennium Cohort Study. • Part of the association between gestational hypertensive disease and asthma was explained by earlier delivery.

Bronchiolitis and recurrent wheezing are distinguished by type 2 innate lymphoid cells and immune response

BACKGROUND

Recurrent wheezing (RW) is frequently developed in infants that have suffered bronchiolitis (BCH) during first months of life, but the immune mechanism underlying is not clear. The goal was to analyze the innate immune response that characterizes BCH and RW.

METHODS

Ninety-eight and seventy hospitalized infants with BCH or RW diagnosis, respectively, were included. Nasopharyngeal aspirate (NPA) was processed. Cellular pellet was employed to evaluate type 2 innate lymphoid cells (ILC2) by flow cytometry and mRNA expression assays by semi-quantitative real-time PCR (qRT-PCR). In supernatant, twenty-seven pro-inflammatory and immunomodulatory factors, as well as lipid mediators and nitrites, were evaluated by ELISA and Luminex.

RESULTS

Bronchiolitis patients showed higher ILC2 percentage compared with RW (P < .05). Also, ST2⁺ /ILC2 percentage was higher in the BCH group than in the RW group (P < .01). TLR3, IL33, IFNG, IL10, and FLG mRNA levels were significantly increased in BCH vs RW (P < .05). In supernatant, no significant differences were reached, observing similar levels of parameters linked to vascular damage, monocyte activation, and fibroblast growth. Prostaglandin E2 and cysteinyl leukotrienes C4 were evaluated; a significant difference was only found in their ratio.

CONCLUSION

Bronchiolitis is associated with elevated nasal percentage of ILC2. This cellular population could be the key element in the differential immune response between BCH and RW which share some mechanisms such us monocyte activation, vascular damage, and fibroblast repair. Lipid mediators could play a role in the evolution of the disease later in life through innate lymphoid cells.

Role of Respiratory Syncytial Virus in Pediatric Pneumonia

Respiratory viral infections represent the leading cause of hospitalization in infants and young children worldwide and the second leading cause of infant mortality. Among these, Respiratory Syncytial Virus (RSV) represents the main cause of lower respiratory tract infections (LRTIs) in young children worldwide. RSV manifestation can range widely from mild upper respiratory infections to severe respiratory infections, mainly bronchiolitis and pneumonia, leading to hospitalization, serious complications (such as respiratory failure), and relevant sequalae in childhood and adulthood (wheezing, asthma, and hyperreactive airways). There are no specific clinical signs or symptoms that can distinguish RSV infection from other respiratory pathogens. New multiplex platforms offer the possibility to simultaneously identify different pathogens, including RSV, with an accuracy similar to that of single polymerase chain reaction (PCR) in the majority of cases. At present, the treatment of RSV infection relies on supportive therapy, mainly consisting of oxygen and hydration. Palivizumab is the only prophylactic method available for RSV infection. Advances in technology and scientific knowledge have led to the creation of different kinds of vaccines and drugs to treat RSV infection. Despite the good level of these studies, there are currently few registered strategies to prevent or treat RSV due to difficulties related to the unpredictable nature of the disease and to the specific target population.

Prevention and treatment of recurrent viral-induced wheezing in the preschool child

OBJECTIVE

To summarize the recent evidence in the treatment of viral-induced wheezing in the infant and preschool aged child.

DATA SOURCES

Published literature obtained through PubMed database searches.

STUDY SELECTIONS

Studies relevant to phenotypes and treatment of wheezing illnesses in infants and preschool children were included.

RESULTS

Recurrent wheezing in preschool children is common and is frequently triggered by viral respiratory tract infections. Certain phenotypes may respond to treatments differently, depending on the risk factors identified. Inhaled corticosteroids, administered continuously or intermittently, reduce the risk of virus-induced wheezing episodes. The use of leukotriene modifying agents may have a role in wheezing episodes in a select group of preschool children. Early administration of azithromycin reduces the risk of severe lower respiratory tract illnesses in children. The effect of oral corticosteroids on wheezing episodes in young children varies by degree of episode severity.

CONCLUSION

Recurrent viral-induced wheezing illnesses has been the focus of many clinical trials, which now provide an increasingly robust evidence base for management. Additional research is needed to define optimal strategies, to best match therapies to specific phenotypes and endotypes, and will eventually begin to include therapies directed specifically at the viral triggers.

Symptom-based screening tool for asthma syndrome among young children in Uganda

Under-diagnosis of asthma in ‘under-fives’ may be alleviated by improved inquiry into disease history. We assessed a questionnaire-based screening tool for asthma among 614 ‘under-fives’ with severe respiratory illness in Uganda. The questionnaire responses were compared to post hoc consensus diagnoses by three pediatricians who were guided by study definitions that were based on medical history, physical examination findings, laboratory and radiological tests, and response to bronchodilators. Children with asthma or bronchiolitis were categorized as “asthma syndrome”. Using this approach, 253 (41.2%) had asthma syndrome. History of and present breathing difficulties and present cough and wheezing was the best performing combination of four questionnaire items [sensitivity 80.8% (95% CI 77.6–84.0); specificity 84.7% (95% CI 81.8–87.6)]. The screening tool for asthma syndrome in ‘under-fives’ may provide a simple, cheap and quick method of identifying children with possible asthma. The validity and reliability of this tool in primary care settings should be tested.

Nutritional status, intake, and outcomes in critically ill children with bronchiolitis

BACKGROUND

Optimal nutrition in children with severe bronchiolitis remains poorly described. We aimed to describe nutritional status and practices in children with severe bronchiolitis requiring admission to the pediatric intensive care unit (PICU), and explore their associations with outcomes.

METHODS

We conducted a retrospective study on patients with bronchiolitis requiring PICU stay from 2009 to 2014. Demographics, medical data, and baseline weight-for-length Z-scores (WLZ) were collected. In patients requiring more than 48 hours of PICU stay, nutritional intake data in the first 3 days of PICU stay were collected. Underfeeding and overfeeding were defined as the median energy intake of less than 80% and more than 120% of requirements, respectively. Protein adequacy was defined as intake of more than 1.5 g/kg/d. Primary and secondary outcomes of interest were the duration of PICU stay and mechanical ventilation (MV), respectively.

RESULTS

Seventy-four patients were included, with a median PICU stay of 4.9 days (interquartile range 2.0-8.2). Low WLZ at baseline was associated with longer duration of PICU stay (adjusted β: 4.33 [95% confidence interval [CI], 0.49-8.18]; P = .028) and MV days (adjusted β: 4.87 [95% CI, 1.56-8.18]; P = .008) compared to appropriate WLZ. In patients with ≥48 hours PICU stay, protein adequacy was significantly associated with greater PICU (adjusted β coefficient, 6.35 [95% CI, 1.66-11.0]; P = .009) and MV days (adjusted β coefficient, 5.22 [95% CI, 1.06-9.38]; P = .015).

CONCLUSION

Among bronchiolitis patients admitted to the PICU, low WLZ at admission was associated with a longer duration of PICU stay and MV. Protein adequacy was associated with longer PICU and MV days in children with ≥48 hours of PICU stay.

Associated Factors for Asthma Severity in Korean Children: A Korean Childhood Asthma Study

Purpose

Childhood asthma has a considerable social impact and economic burden, especially in severe asthma. This study aimed to identify the proportion of childhood asthma severity and to evaluate associated factors for greater asthma severity.

Methods

This study was performed on 667 children aged 5–15 years with asthma from the nationwide 19 hospitals in the Korean childhood Asthma Study (KAS). Asthma was classified as mild intermittent, mild persistent, and moderate/severe persistent groups according to the National Asthma Education and Prevention Program recommendations. Multinomial logistic regression models were used to identify the associated factors for greater asthma severity.

Results

Mild persistent asthma was most prevalent (39.0%), followed by mild intermittent (37.6%), moderate persistent (22.8%), and severe persistent asthma (0.6%). Onset later than 6 years of age (adjusted odds ratio [aOR], 1.69 for mild persistent asthma; aOR, 1.92 for moderate/severe persistent asthma) tended to increase asthma severity. Exposure to environmental tobacco smoke (aOR, 1.53 for mild persistent asthma; aOR, 1.85 for moderate/severe persistent asthma), and current dog ownership with sensitization to dog dander (aOR, 5.86 for mild persistent asthma; aOR, 6.90 for moderate/severe persistent asthma) showed increasing trends with greater asthma severity. Lower maternal education levels (aOR, 2.32) and no usage of an air purifier in exposure to high levels of outdoor air pollution (aOR, 1.76) were associated with moderate/severe persistent asthma.

Conclusions

Modification of identified environmental factors associated with greater asthma severity might help better control childhood asthma, thereby reducing the disease burden due to childhood asthma.

Neonatal priming and infancy boosting with a novel respiratory syncytial virus vaccine induces protective immune responses without concomitant respiratory disease upon RSV challenge

Although respiratory syncytial virus (RSV) infection in infants and young children is a global public health issue, development of a safe RSV vaccine has been impeded by formalin-inactivated RSV-enhanced respiratory disease (ERD). In developing a safer yet effective RSV vaccine for children, a strategy to decrease over-reactive T cells and increase neutralizing anti-RSV antibodies should be considered. We previously demonstrated that adult mice immunized with RSV recombinant G protein plus low-dose Cyclosporine A (G+ CsA) could, upon subsequent RSV challenge, produce increased levels of antigen-specific T regulatory cells in lungs that overcame the ERD. Neutralizing anti-RSV antibodies that prevented viral infection were also elicited. In this study, we investigated if such a G+ CsA vaccine could provide infant mice with the same protection from RSV infection without ERD. The results showed that the G+ CsA vaccine could prevent RSV infection with only a mild loss of body weight. Importantly, there was nearly normal morphology and no mucus appearance in lung tissues after RSV challenge. These results demonstrate that the G+ CsA vaccine strategy achieved similar benefits in the neonatal prime and infancy boost model as in the adult mouse model. The G+ CsA immunization strategy is potentially safe and effective in neonates and infants because it suppresses the devastating ERD.

Gastroenteritis during infancy is a novel risk factor for allergic disease

Antibiotics during infancy, delivery, and breastfeeding affect the intestinal microbiota in early life and is associated with allergic disease. Gastroenteritis (GE) during infancy also affects intestinal microbiota in early life, however, its relationship to allergic disease has not been investigated.Data of 45,499 males and 49,430 females, from birth to 5 years of age, were collected from a national database in Taiwan. Subjects were categorized into early GE (GE within 0-6 months) and non-early GE group (no GE within 0-6 months). The rates of asthma (AS), allergic rhinitis (AR), and atopic dermatitis (AD) over 5 years were evaluated and compared between the groups. In patients with AS, AR, and AD, the number of clinical visits and drug prescriptions for the allergic disease was also evaluated to assess the effect of early GE on allergic disease.After adjusting for the effect of GE in later life and other factors, the rates of AS [OR (odds ratio) 1.54, 95% confidence interval (CI) 1.48-1.60], AR [OR 1.49, 95% CI 1.45-1.54], and AD [OR 1.40, 95% CI 1.33-1.47] were higher in the early GE group than in the non-early GE group. The magnitude of the increase was higher in females than in males. In those with AS, AR, and AD, the number of clinical visits and drug prescriptions was not different between the early GE and non-early GE groups. In children with early GE, good control of GE in the following years lowered the rate of allergic disease.Early-life GE was associated with increased rates of AS, AR, and AD in later life and this was trend more prominent in females.

A biodiversity hypothesis

Biodiversity hypothesis states that contact with natural environments enriches the human microbiome, promotes immune balance and protects from allergy and inflammatory disorders. We are protected by two nested layers of biodiversity, microbiota of the outer layer (soil, natural waters, plants, animals) and inner layer (gut, skin, airways). The latter inhabits our body and is colonized from the outer layer. Explosion of human populations along with cultural evolution is profoundly changing our environment and lifestyle. Adaptive immunoregulatory circuits and dynamic homeostasis are at stake in the newly emerged urban surroundings. In allergy, and chronic inflammatory disorders in general, exploring the determinants of immunotolerance is the key for prevention and more effective treatment. Loss of immunoprotective factors, derived from nature, is a new kind of health risk poorly acknowledged until recently. The paradigm change has been implemented in the Finnish allergy programme (2008-2018), which emphasized tolerance instead of avoidance. The first results are promising, as allergy burden has started to reduce. The rapidly urbanizing world is facing serious biodiversity loss with global warming, which are interconnected. Biodiversity hypothesis of health and disease has societal impact, for example, on city planning, food and energy production and nature conservation. It has also a message for individuals for health and well-being: take nature close, to touch, eat, breathe, experience and enjoy. Biodiverse natural environments are dependent on planetary health, which should be a priority also among health professionals.

Chitinase 3-like 1 protein plays a critical role in respiratory syncytial virus-induced airway inflammation

Background

Chitinase 3‐like 1 protein (CHI3L1) (YKL‐40 in humans and breast regression protein [BRP]‐39 in mice) is required for optimal allergen sensitization and Th2 inflammation in various chronic inflammatory diseases including asthma. However, the role of CHI3L1 in airway inflammation induced by respiratory viruses has not been investigated. The aim of this study was to investigate the relationship between CHI3L1 and airway inflammation caused by respiratory syncytial virus (RSV) infection.

Methods

We measured YKL‐40 levels in human nasopharyngeal aspirate (NPA) from hospitalized children presenting with acute respiratory symptoms. Wild‐type (WT) and BRP‐39 knockout (KO) C57BL/6 mice were inoculated with live RSV (A2 strain). Bronchoalveolar lavage fluid and lung tissue samples were obtained on day 7 after inoculation to assess lung inflammation, airway reactivity, and expression of cytokines and BRP‐39.

Results

In human subjects, YKL‐40 and IL‐13 levels in NPA were higher in children with RSV infection than in control subjects. Expression of BRP‐39 and Th2 cytokines, IL‐13 in particular, was increased following RSV infection in mice. Airway inflammation caused by RSV infection was reduced in BRP‐39 KO mice as compared to WT mice. Th2 cytokine levels were not increased in the lungs of RSV‐infected BRP‐39 KO mice. BRP‐39 regulated M2 macrophage activation in RSV‐infected mice. Additionally, treatment with anti‐CHI3L1 antibody attenuated airway inflammation and Th2 cytokine production in RSV‐infected WT mice.

Conclusion

These findings suggest that CHI3L1 could contribute to airway inflammation induced by RSV infection. CHI3L1 could be a potential therapeutic candidate for attenuating Th2‐associated immunopathology during RSV infection.

Inflammatory and Comorbid Features of Children Admitted to a PICU for Status Asthmaticus

OBJECTIVES

To determine risk factors associated with admission to a PICU with or without endotracheal intubation for an asthma exacerbation. We hypothesized that children with critical and near-fatal asthma would have distinguishing clinical features but varying degrees of asthma severity and measures of type 2 inflammation.

DESIGN

Retrospective analysis of prospectively collected data of children with asthma recruited into outpatient asthma clinical research studies at Emory University between 2004 and 2015.

SETTING

Large, free-standing academic quaternary care children's hospital in Atlanta, GA.

PATIENTS

Children 6-18 years old with physician-diagnosed and confirmed asthma.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 579 children were analyzed with 170 children (29.4%) being admitted to the PICU for an asthma exacerbation in their lifetime. Of these 170 children with a history of critical asthma, 24.1% were classified as having mild-to-moderate asthma, and 83 of 170 children (48.8%) had been intubated and experienced near-fatal asthma. Multiple logistic regression was used to identify risk factors associated with increased odds of PICU admission with or without endotracheal intubation. Hospitalization within the prior 12 months of survey (odds ratio, 8.19; 95% CI, 4.83-13.89), a history of pneumonia (odds ratio, 2.56; 95% CI, 1.52-4.29), having a designation of increased chronic asthma severity on high-dose inhaled corticosteroids (odds ratio, 2.76; 95% CI, 1.62-4.70), having a father with asthma (odds ratio, 2.15; 95% CI, 1.23-3.76), living in a region with a higher burden of poverty (odds ratio, 1.28; 95% CI, 1.02-1.61), and being of black race (odds ratio, 2.01; 95% CI, 1.05-3.84) were all associated with increased odds of PICU admission with or without intubation.

CONCLUSIONS

Our findings suggest that there are factors associated with critical and near-fatal asthma, distinct from the chronic asthma severity designations, that should be the focus of future investigation.

Using urine metabolomics to understand the pathogenesis of infant respiratory syncytial virus (RSV) infection and its role in childhood wheezing

BACKGROUND

Respiratory syncytial virus (RSV) infection in infants causes significant morbidity and is the strongest risk factor associated with asthma. Metabolites, which reflect the interactions between host cell and virus, provide an opportunity to identify the pathways that underlie severe infections and asthma development.

OBJECTIVE

To study metabolic profile differences between infants with RSV infection, and human rhinovirus (HRV) infection, and healthy infants. To compare infant metabolic differences between children who do and do not wheeze.

METHODS

In a term birth cohort, urine was collected while healthy and during acute viral respiratory infection with RSV and HRV. We used ¹H-NMR to identify urinary metabolites. Multivariate and univariate statistics were used to discriminate metabolic profiles of infants with either RSV ARI, or HRV ARI, and healthy infants. Multivariable logistic regression was used to assess the association of urine metabolites with 1st-, 2nd-, and 3rd-year recurrent wheezing.

RESULTS

Several metabolites in nicotinate and nicotinamide metabolism pathways were down-regulated in infants with RSV infection compared to healthy controls. There were no significant differences in metabolite profiles between infants with RSV infection and infants with HRV Infection. Alanine was strongly associated with reduced risk of 1st-year wheezing (OR 0.18[0.0, 0.46]) and 2nd-year wheezing (OR 0.31[0.13, 0.73]), while 2-hydroxyisobutyric acid was associated with increased 3rd-year wheezing (OR 5.02[1.49, 16.93]) only among the RSV infected subset.

CONCLUSION

The metabolites associated with infant RSV infection and recurrent-wheezing are indicative of viral takeover of the cellular machinery and resources to enhance virulence, replication, and subversion of the host immune-response, highlighting metabolic pathways important in the pathogenesis of RSV infection and wheeze development.

Interleukin-13 associates with life-threatening rhinovirus infections in infants and young children

OBJECTIVE

Delineate risk factors associated with severe hypoxemia (O₂ sat ≤87%) in infants and children younger than 2 years hospitalized with single pathogen HRV infection.

STUDY DESIGN

Prospective study in a yearly catchment population of 56 560 children <2 years old between 2011 and 2013 in Argentina. All children with respiratory signs and O₂ sat <93% on admission were included. HRV infections were identified by reverse transcriptase-polymerase chain reaction. Epidemiologic, clinical, viral, and immunological risk factors were assessed.

RESULTS

Among 5012 hospitalized patients, HRV was detected as a single pathogen in 347 (6.92%) subjects. Thirty-two (9.2%) had life-threatening disease. Traditional risk factors for severe bronchiolitis did not affect severity of illness. HRV viral load, HRV groups, and type II and III interferons did not associate with severe hypoxemia. Interleukin-13 Levels in respiratory secretions at the time of admission (OR = 7.43 (3-18.4); P < 0.001 for IL-13 >10 pg/mL) predisposed to life-threatening disease.

CONCLUSIONS

Targeted interventions against IL-13 should be evaluated to decrease severity of HRV illness in infancy and early childhood.

A review of metabolomics approaches and their application in identifying causal pathways of childhood asthma

Because asthma is a disease that results from host-environment interactions, an approach that allows assessment of the effect of the environment on the host is needed to understand the disease. Metabolomics has appealing potential as an application to study pathways to childhood asthma development. The objective of this review is to provide an overview of metabolomics methods and their application to understanding host-environment pathways in asthma development. We reviewed recent literature on advances in metabolomics and their application to study pathways to childhood asthma development. We highlight the (1) potential of metabolomics in understanding the pathogenesis of disease and the discovery of biomarkers; (2) choice of metabolomics techniques, biospecimen handling, and data analysis; (3) application to studying the role of the environment on asthma development; (4) review of metabolomics applied to the outcome of asthma; (5) recommendations for application of metabolomics-based -omics data integration in understanding disease pathogenesis; and (6) limitations. In conclusion, metabolomics allows use of biospecimens to identify useful biomarkers and pathways involved in disease development and subsequently to inform a greater understanding of disease pathogenesis and endotypes and prediction of the clinical course of childhood asthma phenotypes.

Asthma and lung function in adulthood after a viral wheezing episode in early childhood

BACKGROUND

Viral aetiology of infection has a significant role in the long-term outcome of early-childhood wheezing.

OBJECTIVE

This study examines asthma and lung function in adulthood after early-childhood wheezing induced by respiratory syncytial virus (RSV) and rhinovirus (RV).

METHODS

A total of 100 children were hospitalized for a wheezing episode at less than 24 months of age from 1992 to 1993 in Kuopio University Hospital (Finland). Adenovirus, influenza A and B virus, parainfluenza (1-3) virus, and RSV were tested on admission using antigen detection and antibody assays, and RSV and RV were tested by polymerase chain reaction (PCR). In 2010, 49 cases and 60 population controls attended a follow-up study, which included spirometry with bronchodilation test and fractionally exhaled nitric oxide (FE_NO ) measurements.

RESULTS

Current asthma was present in 64% of the cases with RV-induced wheezing (OR 17.0 [95%CI 3.9-75.3] vs controls), in 43% of the cases with RSV-induced wheezing episode (6.1 [1.5-24.9] vs controls), and in 12% of the controls. The RV group showed significantly higher mean FE_NO values than the RSV group and controls. RV-positive cases had lower MEF50 before bronchodilation and higher MEF50, FEV1, and FEV1/FVC bronchodilation responses than controls. RSV-positive cases had lower FVC than controls before bronchodilation.

CONCLUSION

Cases with RV- and RSV-induced early-childhood wheezing had increased risk for asthma in adulthood, and RV-positive cases had significantly higher FE_NO values than RSV-positive cases and controls. Compared to controls, RV-positive cases showed more bronchial reactivity, and RSV-positive cases showed lower FVC before bronchodilation in lung function testing.

CLINICAL RELEVANCE

Children with RV- or RSV-induced wheezing in early childhood have an increased risk for asthma and lung function abnormalities in adulthood.

Early-life respiratory infections and asthma development: role in disease pathogenesis and potential targets for disease prevention

PURPOSE OF REVIEW

This article presents recent findings and perspectives on the relationship between early-life respiratory infections and asthma inception, and discusses emerging concepts on strategies that target these infectious agents for asthma prevention.

RECENT FINDINGS

Cumulative evidence supports the role of early-life viral infections, especially respiratory syncytial virus and human rhinovirus, as major antecedents of childhood asthma. These viruses may have different mechanistic roles in the pathogenesis of asthma. The airway microbiome and virus-bacteria interactions in early life have emerged as additional determinants of childhood asthma. Innovative strategies for the prevention of these early-life infections, or for attenuation of acute infection severity, are being investigated and may identify effective strategies for the primary and secondary prevention of childhood asthma.

SUMMARY

Early-life infections are major determinants of asthma development. The pathway from early-life infections to asthma is the result of complex interactions between the specific type of the virus, genetic, and environmental factors. Novel intervention strategies that target these infectious agents have been investigated in proof-of-concepts trials, and further study is necessary to determine their capacity for asthma prevention.

Vitamin D Status in Infants with Two Different Wheezing Phenotypes

OBJECTIVE

To investigate vitamin D levels in patients with recurrent wheeze at early ages of childhood.

METHODS

In the present cross-sectional study, serum 25-hydroxy vitamin D [25 (OH)D], levels which is known as an indicator of vitamin D adequacy, was examined in infants with three or more wheezing attacks.

RESULTS

A total of 186 infants with recurrent wheezing were included in the study along with 118 healthy control peers. The recurrent wheezing study participants were classified into two groups according to Asthma Predictive Index (API) positivity and compared to control subjects regarding their serum vitamin D status. The API negative group had the lowest mean serum 25 (OH)D level (n = 121; 22.71 ± 10.76 ng/ml) followed by API positive group (n = 65; 24.08 ± 9.02 ng/ml) compared to healthy group (26.24 ± 11.88 ng/ml) (p < 0.05). In addition, higher vitamin D deficiency was observed in infants in API negative group (52.1 %; p < 0.01) and API positive group (38.5 %; p < 0.05) than control group (31.4 %).

CONCLUSIONS

Low levels of 25 (OH)D were detected in infants with two different phenotypes of recurrent wheeze. Vitamin D deficiency may play a role in the pathogenesis of infants with recurrent wheezing.

Interaction between 25-hydroxyvitamin D and variants at 17q12-21 on respiratory infections

OBJECTIVES

25-hydroxyvitamin D (25[OH]D) deficiency and genetic variants at the 17q12-21 locus are independent risk factors for respiratory tract infections (RTIs). We aimed to investigate whether the effect of 25(OH)D at birth and 1 year of age and the polymorphism at the 17q12-21 locus, or interactions between these two factors, increase susceptibility to RTIs in the first year of life.

METHODS

We tested cord-blood (CB) 25(OH)D at birth and 1 year of age and genotypes of a variant at the 17q12-21 locus for associations with RTIs, particularly lower respiratory tract infections (LRTIs), and determined whether there exist interactions between 25(OH)D and 17q12-21 genotypes in a birth cohort of 473 infants.

RESULTS

The levels of CB 25(OH)D inversely associate with development of RTIs and LRTIs during the first year of life. There exists an inverse association of 25(OH)D at birth, but not at 1 year, with the risk of acquiring LRTIs in early infancy (adjusted odds ratio [aOR], 2.37; 95% confidence interval [CI]: 1.23-4.60; P = 0.010 and aOR, 0.50; 95%CI: 0.23-1.12; P = 0.094). We have also found a significant interaction between CB 25(OH)D and a variant at the 17q12-21 locus with respect to the development of early LRTIs, such that associations between a variant at the 17q12-21 locus and LRTIs are restricted to infants with low CB 25(OH)D concentrations (P for interaction = 0.013). In addition, when infants with a variant at the 17q12-21 locus had been exposed to chronic 25(OH)D deficiency over the first year, their risk of LRTIs was increased.

CONCLUSION

CB 25(OH)D deficiency during fetal life contribute to the development of LRTIs in genetically susceptible infants. Pediatr Pulmonol. 2016; 51:958-967. © 2016 Wiley Periodicals, Inc.

Update on Human Rhinovirus and Coronavirus Infections

Human rhinovirus (HRV) and coronavirus (HCoV) infections are associated with both upper respiratory tract illness (“the common cold”) and lower respiratory tract illness (pneumonia). New species of HRVs and HCoVs have been diagnosed in the past decade. More sensitive diagnostic tests such as reverse transcription-polymerase chain reaction have expanded our understanding of the role these viruses play in both immunocompetent and immunosuppressed hosts. Recent identification of severe acute respiratory syndrome and Middle East respiratory syndrome viruses causing serious respiratory illnesses has led to renewed efforts for vaccine development. The role these viruses play in patients with chronic lung disease such as asthma makes the search for antiviral agents of increased importance.

Pediatric Asthma and Viral Infection

Respiratory viral infections, particularly respiratory syncytial virus (RSV) and rhinovirus, are the most importance risk factors for the onset of wheezing in infants and small children. Bronchiolitis is the most common acute respiratory infection in children under 1year of age, and the most common cause of hospitalization in this age group. RSV accounts for approximately 70% of all these cases, followed by rhinovirus, adenovirus, metapneumovirus and bocavirus. The association between bronchiolitis caused by RSV and the development of recurrent wheezing and/or asthma was first described more than 40years ago, but it is still unclear whether bronchiolitis causes chronic respiratory symptoms, or if it is a marker for children with a genetic predisposition for developing asthma in the medium or long term. In any case, sufficient evidence is available to corroborate the existence of this association, which is particularly strong when the causative agent of bronchiolitis is rhinovirus. The pathogenic role of respiratory viruses as triggers for exacerbations in asthmatic patients has not been fully characterized. However, it is clear that respiratory viruses, and in particular rhinovirus, are the most common causes of exacerbation in children, and some type of respiratory virus has been identified in over 90% of children hospitalized for an episode of wheezing. Changes in the immune response to viral infections in genetically predisposed individuals are very likely to be the main factors involved in the association between viral infection and asthma.

Pediatric Asthma and Viral Infection

Respiratory viral infections, particularly respiratory syncytial virus (RSV) and rhinovirus, are the most importance risk factors for the onset of wheezing in infants and small children. Bronchiolitis is the most common acute respiratory infection in children under 1 year of age, and the most common cause of hospitalization in this age group. RSV accounts for approximately 70% of all these cases, followed by rhinovirus, adenovirus, metapneumovirus and bocavirus. The association between bronchiolitis caused by RSV and the development of recurrent wheezing and/or asthma was first described more than 40 years ago, but it is still unclear whether bronchiolitis causes chronic respiratory symptoms, or if it is a marker for children with a genetic predisposition for developing asthma in the medium or long term. In any case, sufficient evidence is available to corroborate the existence of this association, which is particularly strong when the causative agent of bronchiolitis is rhinovirus.

The pathogenic role of respiratory viruses as triggers for exacerbations in asthmatic patients has not been fully characterized. However, it is clear that respiratory viruses, and in particular rhinovirus, are the most common causes of exacerbation in children, and some type of respiratory virus has been identified in over 90% of children hospitalized for an episode of wheezing. Changes in the immune response to viral infections in genetically predisposed individuals are very likely to be the main factors involved in the association between viral infection and asthma.

A systematic review of predictive models for asthma development in children

BACKGROUND

Asthma is the most common pediatric chronic disease affecting 9.6 % of American children. Delay in asthma diagnosis is prevalent, resulting in suboptimal asthma management. To help avoid delay in asthma diagnosis and advance asthma prevention research, researchers have proposed various models to predict asthma development in children. This paper reviews these models.

METHODS

A systematic review was conducted through searching in PubMed, EMBASE, CINAHL, Scopus, the Cochrane Library, the ACM Digital Library, IEEE Xplore, and OpenGrey up to June 3, 2015. The literature on predictive models for asthma development in children was retrieved, with search results limited to human subjects and children (birth to 18 years). Two independent reviewers screened the literature, performed data extraction, and assessed article quality.

RESULTS

The literature search returned 13,101 references in total. After manual review, 32 of these references were determined to be relevant and are discussed in the paper. We identify several limitations of existing predictive models for asthma development in children, and provide preliminary thoughts on how to address these limitations.

CONCLUSIONS

Existing predictive models for asthma development in children have inadequate accuracy. Efforts to improve these models' performance are needed, but are limited by a lack of a gold standard for asthma development in children.

Clinical Endpoints for Respiratory Syncytial Virus Prophylaxis Trials in Infants and Children in High-income and Middle-income Countries

Respiratory syncytial virus (RSV) continues to cause significant clinical and economic burden around the world. Historically, RSV-associated hospitalization was used as a primary endpoint for RSV prophylaxis trials in infants. However, because of the changing epidemiology and healthcare system landscape, this endpoint has become a critical bottleneck on the pathway to licensure for new therapeutics. A panel of 7 RSV experts was convened (Chicago, IL, May 22, 2014) to evaluate the challenges of defining RSV prevention endpoints for clinical trials and to develop endpoints that are clinically meaningful while minimizing subjectivity and bias to achieve sufficient consistency of response for regulatory approval. Particular consideration was given to the ability to collect data systematically and consistently in countries with different healthcare practices and systems, while capturing the greatest proportion of disease impact. The group consensus was that a clinically meaningful primary endpoint could include medically attended RSV illness in settings beyond RSV-associated hospitalizations alone, in particular, a composite reduction in hospitalization, emergency room or urgent care center visits because of an RSV respiratory infection. Relevant secondary endpoints included reductions in RSV lower respiratory tract infection, RSV-related intensive care unit rates, subsequent recurrent wheezing or asthma and direct and indirect costs.

Marital Quality and Stress in Pregnancy Predict the Risk of Infectious Disease in the Offspring: The Norwegian Mother and Child Cohort Study

OBJECTIVES

The aim of this study was to explore the degree to which couples' relationship dissatisfaction and stressful life events during pregnancy predict the risk of infectious disease in the offspring during their first year of life.

METHODS

Data were obtained from the Norwegian Mother and Child Cohort Study, conducted by the Norwegian Institute of Public Health. Pregnant women completed questionnaires in week 30 of pregnancy concerning the couples' relationship satisfaction and stressful life events. In follow-up questionnaires, the women reported whether their children (n = 74,801) had been subject to various categories of infectious disease: the common cold, throat infection, bronchitis, RS virus, pneumonia, pseudocroup, gastric flu, ear infection, conjunctivitis and urinary tract infection. Reports from two age groups of infants were used. Associations between the predictor and outcome variables were assessed via logistic regression and linear regression analyses.

RESULTS

Separate logistic regression analyses for each disease and age group showed that prenatal relationship dissatisfaction and stressful life events were significantly associated with all reported categories of infectious disease. After controlling for socioeconomic factors, social support, smoking, breastfeeding, maternal depression, the sex of the offspring, and use of child care, 29 out of 32 tested associations were statistically significant. Finally, multivariate linear regression analyses showed that prenatal relationship dissatisfaction and stressful life events were significantly associated with the frequency, as well as the variety, of infectious disease in the offspring.

Lower respiratory tract infection caused by respiratory syncytial virus: current management and new therapeutics

Respiratory syncytial virus (RSV) is a major worldwide cause of morbidity and mortality in children under five years of age. Evidence-based management guidelines suggest that there is no effective treatment for RSV lower respiratory tract infection (LRTI) and that supportive care, ie, hydration and oxygenation, remains the cornerstone of clinical management. However, RSV treatments in development in the past decade include 10 vaccines and 11 therapeutic agents in active clinical trials. Maternal vaccination is particularly relevant because the most severe disease occurs within the first 6 months of life, when children are unlikely to benefit from active immunisation. We must optimise the implementation of novel RSV therapeutics by understanding the target populations, showing safety, and striving for acceptable pricing in the context of this worldwide health problem. In this Review, we outline the limitations of RSV LRTI management, the drugs in development, and the remaining challenges related to study design, regulatory approval, and implementation.

The microbiome of the human lower airways: a next generation sequencing perspective

For a long time, the human lower airways were considered a sterile environment where the presence of microorganisms, typically revealed by culturing, was interpreted as an abnormal health state. More recently, high-throughput sequencing-based studies have led to a shift in this perception towards the notion that even in healthy conditions the lower airways show either transient presence or even permanent colonization by microorganisms. However, challenges related to low biomass and contamination in samples still remain, and the composition, structure and dynamics of such putative microbial communities are unclear. Here, we review the evidence for the presence of microbial communities in the human lower airways, in healthy subjects and within the context of medical conditions of interest. We also provide an overview of the methodology pertinent to high-throughput sequencing studies, specifically those based on amplicon sequencing, including a discussion of good practices and common pitfalls.

Challenges and opportunities in developing respiratory syncytial virus therapeutics

Two meetings, one sponsored by the Wellcome Trust in 2012 and the other by the Global Virology Foundation in 2013, assembled academic, public health and pharmaceutical industry experts to assess the challenges and opportunities for developing antivirals for the treatment of respiratory syncytial virus (RSV) infections. The practicalities of clinical trials and establishing reliable outcome measures in different target groups were discussed in the context of the regulatory pathways that could accelerate the translation of promising compounds into licensed agents. RSV drug development is hampered by the perceptions of a relatively small and fragmented market that may discourage major pharmaceutical company investment. Conversely, the public health need is far too large for RSV to be designated an orphan or neglected disease. Recent advances in understanding RSV epidemiology, improved point-of-care diagnostics, and identification of candidate antiviral drugs argue that the major obstacles to drug development can and will be overcome. Further progress will depend on studies of disease pathogenesis and knowledge provided from controlled clinical trials of these new therapeutic agents. The use of combinations of inhibitors that have different mechanisms of action may be necessary to increase antiviral potency and reduce the risk of resistance emergence.

Vitamin D as an adjunctive therapy in asthma. Part 1: A review of potential mechanisms

Vitamin D deficiency (VDD) is highly prevalent worldwide. The classical role for vitamin D is to regulate calcium absorption form the gastrointestinal tract and influence bone health. Recently vitamin D receptors and vitamin D metabolic enzymes have been discovered in numerous sites systemically supporting diverse extra-skeletal roles of vitamin D, for example in asthmatic disease. Further, VDD and asthma share several common risk factors including high latitude, winter season, industrialization, poor diet, obesity, and dark skin pigmentation. Vitamin D has been demonstrated to possess potent immunomodulatory effects, including effects on T cells and B cells as well as increasing production of antimicrobial peptides (e.g. cathelicidin). This immunomodulation may lead to asthma specific clinical benefits in terms of decreased bacterial/viral infections, altered airway smooth muscle-remodeling and -function as well as modulation of response to standard anti-asthma therapy (e.g. glucocorticoids and immunotherapy). Thus, vitamin D and its deficiency have a number of biological effects that are potentially important in altering the course of disease pathogenesis and severity in asthma. The purpose of this first of a two-part review is to review potential mechanisms whereby altering vitamin D status may influence asthmatic disease.

Gestational age-specific associations between infantile acute bronchiolitis and asthma after age five

BACKGROUND

Infantile acute bronchiolitis (AB) is a risk factor for the development of paediatric asthma. The associations might differ according to gestational age.

METHODS

Data sets of emergency department (ED) visits (January 2002 to June 2010) and livebirth records (January 2002 to December 2004) from the state of Georgia were linked for all children who survived 1 year. Exposure was an ED visit for AB during infancy, and the outcome was an ED visit for asthma after age 5 years. The risk of asthma among children with AB (n = 11 564) was compared with the risk of asthma among children who did not have an ED visit for AB but who utilised the ED for another reason during infancy (n = 131 694). Associations were estimated using log-binomial regression models that controlled for several plausible confounders. Effect measure modification of the risk ratio by gestational age was investigated.

RESULTS

Unadjusted asthma risks (per 100 children) through June 2010 were 4.5 for children with AB and 2.3 for children without AB. The adjusted risk ratio for the overall association was 1.9 [95% confidence interval 1.7, 2.1]. We did not observe effect modification of the risk ratio by gestational age.

CONCLUSION

A positive association was observed between ED visits for AB and subsequent asthma ED visits after age 5; associations did not vary meaningfully by gestational age. Sensitivity analyses did not suggest large biases due to differences in ED utilisation across sociodemographic groups or loss to follow-up from residential migration.

The relationships between environmental bacterial exposure, airway bacterial colonization, and asthma

PURPOSE OF REVIEW

Recent application of advanced culture-independent molecular techniques for the identification of microorganisms has contributed to our knowledge on the role of early-life microbial exposure and colonization in health and disease. The purpose of this review is to present the current perspectives regarding the role of microbial exposure and airway bacterial colonization on the development and the activity of asthma.

RECENT FINDINGS

Recent findings continue to support the protective role of early-life diverse microbial exposure against the development of atopic diseases. However, airway bacterial colonization early in life serves as a risk factor for the development of asthma. Culture-independent molecular techniques for the identification of microorganisms have challenged the traditional paradigm that the lower airway is a sterile compartment. Asthmatics, compared with nonasthmatics, appear to have a different lung microbiome composition and some of these differences might contribute to asthma activity, severity, and corticosteroid response.

SUMMARY

Bacterial presence in the airway appears to influence the inception and may affect the activity of asthma. Complex interactions between different types and routes of bacterial exposures, the airway, and the immune system early in life may determine whether these exposures augment or reduce the risk of asthma development.

Is vitamin D insufficiency to blame for recurrent wheezing?

BACKGROUND

Vitamin D (VitD) and its metabolites play important roles in the regulation of the respiratory and immune systems. The aim of this study was to examine serum 25(OH) vitamin D [25(OH)D] levels and VitD deficiency on the development of wheezing and clinical features.

METHODS

This study was a prospective cross-sectional survey that included a total of 70 infants being followed in the Pediatric Immunology and Allergy Unit at Ondokuz Mayis University. Forty of these infants (patient group), ranging in age from 1 to 3 years, had been diagnosed as wheezy infants; 30 were age-and-gender matched healthy infants (control group). Prior to the study, blood samples were taken from both groups to determine their serum VitD, blood eosinophil, and serum immunoglobulin E (IgE) levels.

RESULTS

The duration of breastfeeding was similar for both groups. The serum 25(OH)D levels of the patient group were significantly lower than those of the control group. Although there was a negative relationship between 25(OH)D level and IgE(log10) values for the wheezy infants with VitD deficiency, the control group had a negative relationship between VitD level and IgE(log10) .

CONCLUSION

Serum 25(OH)D levels must be evaluated when following wheezy infants, and those with deficiency must be treated with VitD.

A systematic review of predictive modeling for bronchiolitis

PURPOSE

Bronchiolitis is the most common cause of illness leading to hospitalization in young children. At present, many bronchiolitis management decisions are made subjectively, leading to significant practice variation among hospitals and physicians caring for children with bronchiolitis. To standardize care for bronchiolitis, researchers have proposed various models to predict the disease course to help determine a proper management plan. This paper reviews the existing state of the art of predictive modeling for bronchiolitis. Predictive modeling for respiratory syncytial virus (RSV) infection is covered whenever appropriate, as RSV accounts for about 70% of bronchiolitis cases.

METHODS

A systematic review was conducted through a PubMed search up to April 25, 2014. The literature on predictive modeling for bronchiolitis was retrieved using a comprehensive search query, which was developed through an iterative process. Search results were limited to human subjects, the English language, and children (birth to 18 years).

RESULTS

The literature search returned 2312 references in total. After manual review, 168 of these references were determined to be relevant and are discussed in this paper. We identify several limitations and open problems in predictive modeling for bronchiolitis, and provide some preliminary thoughts on how to address them, with the hope to stimulate future research in this domain.

CONCLUSIONS

Many problems remain open in predictive modeling for bronchiolitis. Future studies will need to address them to achieve optimal predictive models.

Recurrent wheezing is associated with intestinal protozoan infections in Warao Amerindian children in Venezuela: a cross-sectional survey

Background

While in developed countries the prevalence of allergic diseases is rising, inflammatory diseases are relatively uncommon in rural developing areas. High prevalence rates of helminth and protozoan infections are commonly found in children living in rural settings and several studies suggest an inverse association between helminth infections and allergies. No studies investigating the relationship between parasitic infections and atopic diseases in rural children of developing countries under the age of 2 years have been published so far. We performed a cross-sectional survey to investigate the association of helminth and protozoan infections and malnutrition with recurrent wheezing and atopic eczema in Warao Amerindian children in Venezuela.

Methods

From August to November 2012, 229 children aged 0 to 2 years residing in the Orinoco Delta in Venezuela were enrolled. Data were collected through standardized questionnaires and physical examination, including inspection of the skin and anthropometric measurements. A stool sample was requested from all participants and detection of different parasites was performed using microscopy and real time polymerase chain reaction (PCR).

Results

We observed high prevalence rates of atopic eczema and recurrent wheezing, respectively 19% and 23%. The prevalence of helminth infections was 26% and the prevalence of protozoan infections was 59%. Atopic eczema and recurrent wheezing were more frequently observed in stunted compared with non-stunted children in multivariable analysis (OR 4.3, 95% CI 1.3 – 13.6, p = 0.015 and OR 4.5, 95% CI 0.97 – 21.2, p = 0.055). Furthermore, recurrent wheezing was significantly more often observed in children with protozoan infections than in children without protozoan infections (OR 6.7, 95% CI 1.5 – 30.5).

Conclusions

High prevalence rates of atopic eczema and recurrent wheezing in Warao Amerindian children under 2 years of age were related to stunting and intestinal protozoan infections respectively. Helminth infections were not significantly associated with either atopic eczema or recurrent wheezing.

Infectious pathogens and bronchiolitis outcomes

Bronchiolitis is a common early childhood illness and an important cause of morbidity, it is the number one cause of hospitalization among US infants. Bronchiolitis is also an active area of research, and recent studies have advanced our understanding of this illness. Although it has long been the conventional wisdom that the infectious etiology of bronchiolitis does not affect outcomes, a growing number of studies have linked specific pathogens of bronchiolitis (e.g., rhinovirus) to short- and long-term outcomes, such as future risk of developing asthma. The authors review the advent of molecular diagnostic techniques that have demonstrated diverse pathogens in bronchiolitis, and they review recent studies on the complex link between infectious pathogens of bronchiolitis and the development of childhood asthma.

Acute bronchiolitis in infants, a review

Acute viral bronchiolitis is one of the most common medical emergency situations in infancy, and physicians caring for acutely ill children will regularly be faced with this condition. In this article we present a summary of the epidemiology, pathophysiology and diagnosis, and focus on guidelines for the treatment of bronchiolitis in infants. The cornerstones of the management of viral bronchiolitis are the administration of oxygen and appropriate fluid therapy, and overall a “minimal handling approach” is recommended. Inhaled adrenaline is commonly used in some countries, but the evidences are sparse. Recently, inhalation with hypertonic saline has been suggested as an optional treatment. When medical treatment fails to stabilize the infants, non-invasive and invasive ventilation may be necessary to prevent and support respiratory failure. It is important that relevant treatment algorithms exist, applicable to all levels of the treatment chain and reflecting local considerations and circumstances.