Nasopharyngeal CCL5 in infants with severe bronchiolitis and risk of recurrent wheezing: A multi-center prospective cohort study

Application of Asthma Prediction Tools in a Cohort of Infants with Severe Bronchiolitis

Background: Severe bronchiolitis is a strong childhood asthma risk factor. Early and accurate asthma prediction is key. We applied the Asthma Predictive Index (API), the modified Asthma Predictive Index (mAPI), and the Pediatric Asthma Risk Score (PARS) in a cohort of high-risk infants to predict asthma at age 6 years. Methods: We conducted a 17-center cohort of infants (age <1 year) hospitalized with severe bronchiolitis during 2011-2014. We used only infancy data to predict asthma at age 6 years. Results: The prevalence of parent-reported asthma at age 6 years was 328/880 (37%). The prevalences of a positive index/score for stringent and loose API, mAPI, and PARS were 21%, 51%, 11%, and 34%, respectively. Area under the receiver operating characteristic curves [95% confidence interval (CI)] ranged from 0.57 (95% CI 0.55-0.60) for mAPI to 0.66 (95% CI 0.63-0.70) for PARS. Conclusions: An asthma prediction tool for high-risk infants is needed to identify those who would benefit most from asthma prevention interventions.

Proteomics endotyping of infants with severe bronchiolitis and risk of childhood asthma

BACKGROUND

Bronchiolitis is the leading cause of hospitalization in U.S. infants and a major risk factor for childhood asthma. Growing evidence supports clinical heterogeneity within bronchiolitis. We aimed to identify endotypes of infant bronchiolitis by integrating clinical, virus, and serum proteome data, and examine their relationships with asthma development.

METHODS

This is a multicenter prospective cohort study of infants hospitalized for physician-diagnosis of bronchiolitis. We identified bronchiolitis endotypes by applying unsupervised machine learning (clustering) approaches to integrated clinical, virus (respiratory syncytial virus [RSV], rhinovirus [RV]), and serum proteome data measured at hospitalization. We then examined their longitudinal association with the risk for developing asthma by age 6 years.

RESULTS

In 140 infants hospitalized with bronchiolitis, we identified three endotypes: (1) clinicalatopic virusRV proteomeNFκB-dysregulated , (2) clinicalnon-atopic virusRSV/RV proteomeTNF-dysregulated , and (3) clinicalclassic virusRSV proteomeNFκB/TNF-regulated endotypes. Endotype 1 infants were characterized by high proportion of IgE sensitization and RV infection. These endotype 1 infants also had dysregulated NFκB pathways (FDR < 0.001) and significantly higher risks for developing asthma (53% vs. 22%; adjOR 4.04; 95% CI, 1.49-11.0; p = 0.006), compared with endotype 3 (clinically resembling "classic" bronchiolitis). Likewise, endotype 2 infants were characterized by low proportion of IgE sensitization and high proportion of RSV or RV infection. These endotype 2 infants had dysregulated tumor necrosis factor (TNF)-mediated signaling pathway (FDR <0.001) and significantly higher risks for developing asthma (44% vs. 22%; adjOR 2.71; 95% CI, 1.03-7.11, p = 0.04).

CONCLUSION

In this multicenter cohort, integrated clustering of clinical, virus, and proteome data identified biologically distinct endotypes of bronchiolitis that have differential risks of asthma development.

Impact of genetic polymorphisms related to innate immune response on respiratory syncytial virus infection in children

Respiratory syncytial virus (RSV) causes lower respiratory tract infections and bronchiolitis, mainly affecting children under 2 years of age and immunocompromised patients. Currently, there are no available vaccines or efficient pharmacological treatments against RSV. In recent years, tremendous efforts have been directed to understand the pathological mechanisms of the disease and generate a vaccine against RSV. Although RSV is highly infectious, not all the patients who get infected develop bronchiolitis and severe disease. Through various sequencing studies, single nucleotide polymorphisms (SNPs) have been discovered in diverse receptors, cytokines, and transcriptional regulators with crucial role in the activation of the innate immune response, which is implicated in the susceptibility to develop or protect from severe forms of the infection. In this review, we highlighted how variations in the key genes affect the development of innate immune response against RSV. This data would provide crucial information about the mechanisms of viral infection, and in the future, could help in generation of new strategies for vaccine development or generation of the pharmacological treatments.

Association of Nasopharyngeal and Serum Glutathione Metabolism with Bronchiolitis Severity and Asthma Risk: A Prospective Multicenter Cohort Study

Infants hospitalized for bronchiolitis are at high risk for asthma. Glutathione-related metabolites may antagonize oxidative stress, which induces airway injuries in respiratory infection and subsequent airway remodeling. However, little is known about the relationship of glutathione-related metabolites with bronchiolitis severity and the risk of asthma. In a multicenter prospective observational cohort study of infants hospitalized for bronchiolitis, we measured nasopharyngeal and serum glutathione-related metabolites by using liquid chromatography−tandem mass spectrometry. We then examined their association with bronchiolitis severity (defined by positive pressure ventilation (PPV) use). We also identified severity-related glutathione-related metabolite signatures and examined their association with asthma at age 6 years. In 1013 infants, we identified 12 nasopharyngeal and 10 serum glutathione-related metabolites. In the multivariable models, lower relative abundances of seven metabolites, e.g., substrates of glutathione, including cysteine (adjOR 0.21, 95%CI 0.06−0.76), glycine (adjOR 0.25, 95%CI 0.07−0.85), and glutamate (adjOR 0.25, 95%CI 0.07−0.88), were significantly associated with PPV use (all FDR < 0.05). These associations were consistent with serum glutathione-related metabolites. The nasopharyngeal glutathione-related metabolite signature was also associated with a significantly higher risk of asthma (adjOR 0.90, 95%CI 0.82−0.99, p = 0.04). In infants hospitalized for bronchiolitis, glutathione-related metabolites were associated with bronchiolitis severity and asthma risk.

The role of respiratory syncytial virus- and rhinovirus-induced bronchiolitis in recurrent wheeze and asthma-A systematic review and meta-analysis

INTRODUCTION

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. RSV-induced bronchiolitis has been associated with preschool wheeze and asthma in cohort studies where the comparison groups consist of healthy infants. However, recent studies identify rhinovirus (RV)-induced bronchiolitis as a potentially stronger risk factor for recurrent wheeze and asthma.

AIM

This systematic review and meta-analysis aimed to compare the associations of RSV- and RV-induced bronchiolitis with the development of preschool wheeze and childhood asthma.

METHODS

We performed a systematic search of the published literature in five databases by using a MeSH term-based algorithm. Cohort studies that enrolled infants with bronchiolitis were included. The primary outcomes were recurrent wheeze and asthma diagnosis. Wald risk ratios and odds ratios (ORs) were estimated, along with their 95% confidence intervals (CIs). Individual and summary ORs were visualized with forest plots.

RESULTS

There were 38 studies included in the meta-analysis. Meta-analysis of eight studies that had data on the association between infant bronchiolitis and recurrent wheeze showed that the RV-bronchiolitis group were more likely to develop recurrent wheeze than the RSV-bronchiolitis group (OR 4.11; 95% CI 2.24-7.56). Similarly, meta-analysis of the nine studies that had data on asthma development showed that the RV-bronchiolitis group were more likely to develop asthma (OR 2.72; 95% CI 1.48-4.99).

CONCLUSION

This is the first meta-analysis that directly compares between-virus differences in the magnitude of virus-recurrent wheeze and virus-childhood asthma outcomes. RV-induced bronchiolitis was more strongly associated with the risk of developing wheeze and childhood asthma.

Performance of Three Asthma Predictive Tools in a Cohort of Infants Hospitalized With Severe Bronchiolitis

Childhood asthma develops in 30–40% of children with severe bronchiolitis but accurate prediction remains challenging. In a severe bronchiolitis cohort, we applied the Asthma Predictive Index (API), the modified Asthma Predictive Index (mAPI), and the Pediatric Asthma Risk Score (PARS) to predict asthma at age 5 years. We applied the API, mAPI, and PARS to the 17-center cohort of infants hospitalized with severe bronchiolitis during 2011–2014 (35th Multicenter Airway Research Collaboration, MARC-35). We used data from the first 3 years of life including parent interviews, chart review, and specific IgE testing to predict asthma at age 5 years, defined as parent report of clinician-diagnosed asthma. Among 875/921 (95%) children with outcome data, parent-reported asthma was 294/875 (34%). In MARC-35, a positive index/score for stringent and loose API, mAPI, and PARS were 24, 68, 6, and 55%, respectively. The prediction tools' AUCs (95%CI) ranged from 0.57 (95%CI 0.54–0.59) to 0.68 (95%CI 0.65–0.71). The positive likelihood ratios were lower in MARC-35 compared to the published results from the original cohorts. In this high-risk population of infants hospitalized with severe bronchiolitis, API, mAPI, and PARS had sub-optimal performance (AUC &lt;0.8). Highly accurate (AUC &gt;0.8) asthma prediction tools are desired in infants hospitalized with severe bronchiolitis.

A comparison of case definitions for infant atopic dermatitis in a multicenter prospective cohort study

This study identified two infant AD case definitions that were strongly associated with known AD risk factors. These case definitions can be used to study novel AD risk factors in large cohort studies, potentially providing new insights into the epidemiology of infant AD.

Integrated omics endotyping of infants with respiratory syncytial virus bronchiolitis and risk of childhood asthma

Respiratory syncytial virus (RSV) bronchiolitis is not only the leading cause of hospitalization in U.S. infants, but also a major risk factor for asthma development. While emerging evidence suggests clinical heterogeneity within RSV bronchiolitis, little is known about its biologically-distinct endotypes. Here, we integrated clinical, virus, airway microbiome (species-level), transcriptome, and metabolome data of 221 infants hospitalized with RSV bronchiolitis in a multicentre prospective cohort study. We identified four biologically- and clinically-meaningful endotypes: A) clinicalclassicmicrobiomeM. nonliquefaciensinflammationIFN-intermediate, B) clinicalatopicmicrobiomeS. pneumoniae/M. catarrhalisinflammationIFN-high, C) clinicalseveremicrobiomemixedinflammationIFN-low, and D) clinicalnon-atopicmicrobiomeM.catarrhalisinflammationIL-6. Particularly, compared with endotype A infants, endotype B infants-who are characterized by a high proportion of IgE sensitization and rhinovirus coinfection, S. pneumoniae/M. catarrhalis codominance, and high IFN-α and -γ response-had a significantly higher risk for developing asthma (9% vs. 38%; OR, 6.00: 95%CI, 2.08-21.9; P = 0.002). Our findings provide an evidence base for the early identification of high-risk children during a critical period of airway development.

Proximity to Major Roads and Risks of Childhood Recurrent Wheeze and Asthma in a Severe Bronchiolitis Cohort

Air pollution exposures have been suggested as risk factors for childhood respiratory diseases. We investigated proximity to major roads, an indicator of air pollution exposure, and its associations with childhood recurrent wheeze and asthma. We used data from a multicenter prospective cohort study of 921 infants hospitalized for bronchiolitis and recruited from 14 U.S. states. Primary exposure was residential proximity to the nearest major road at birth through age 3 years. Residential distance from nearest major road was divided into four categories: <100, 100–200, 201–300, and >300 m. Outcomes were parent-reported recurrent wheeze by age 3 years and asthma by age 5 years. Associations between residential proximity to major roads and respiratory outcomes were investigated using multivariable Cox proportional hazards modeling and logistic regression, adjusted for confounders. Out of 920 participants with home address data, pooled estimates identified 241 (26%) participants resided within 300 m of a major road, 296 (32%) developed recurrent wheeze by age 3, and 235 out of 858 participants (27%) developed asthma by 5 years. Participants who resided close to a major road had the highest risk of recurrent wheeze (adjusted hazards ratio for <100 m, 1.59, 95%CI: 1.08–2.33) and asthma (adjusted odds ratio for 201–300 m, 1.62, 95%CI: 1.16–2.25), compared to those residing >300 m from a major road. Proximity to major roads is associated with increased risks of recurrent wheeze and asthma in young children.

Respiratory Virus Epidemiology Among US Infants With Severe Bronchiolitis: Analysis of 2 Multicenter, Multiyear Cohort Studies

In 2 multicenter cohort studies of 2912 infants hospitalized for bronchiolitis during 2007-2014, the 5 most common pathogens were RSV (76.5%), rhinovirus (23.8%), coronavirus (6.9%), adenovirus (6.4%) and human metapneumovirus (6.0%). Hospitalization months significantly differed for these common pathogens (P ≤ 0.01), except for coronavirus (P = 0.30). There was a significant heterogeneity in temporal patterns by region in RSV-A and -B (both P < 0.001).

Association of Rhinovirus C Bronchiolitis and Immunoglobulin E Sensitization During Infancy With Development of Recurrent Wheeze

IMPORTANCE

Rhinovirus infection in early life, particularly with allergic sensitization, is associated with higher risks of developing recurrent wheeze and asthma. While emerging evidence links different rhinovirus species (eg, rhinovirus C) to a higher severity of infection and asthma exacerbation, to our knowledge, little is known about longitudinal associations of rhinovirus C infection during infancy with subsequent morbidities.

OBJECTIVE

To examine the association of different viruses (respiratory syncytial virus [RSV], rhinovirus species) in bronchiolitis with risks of developing recurrent wheeze.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter prospective cohort study of infants younger than 1 year who were hospitalized for bronchiolitis was conducted at 17 hospitals across 14 US states during 3 consecutive fall to winter seasons (2011-2014).

EXPOSURES

Major causative viruses of bronchiolitis, including RSV (reference group) and 3 rhinovirus species (rhinovirus A, B, and C).

MAIN OUTCOMES AND MEASURES

Development of recurrent wheeze (as defined in national asthma guidelines) by age 3 years.

RESULTS

This analytic cohort comprised 716 infants who were hospitalized for RSV-only or rhinovirus bronchiolitis. The median age was 2.9 months (interquartile range, 1.6-3.8 months), 541 (76%) had bronchiolitis with RSV only, 85 (12%) had rhinovirus A, 12 (2%) had rhinovirus B, and 78 (11%) had rhinovirus C infection. Overall, 231 (32%) developed recurrent wheeze by age 3 years. In the multivariable Cox model, compared with infants with RSV-only infection, the risk of recurrent wheeze was not significantly different in those with rhinovirus A or B (rhinovirus A: hazard ratio [HR], 1.27; 95% CI, 0.86-1.88; rhinovirus B: HR, 1.39; 95% CI, 0.51-3.77; both P > .10). By contrast, infants with rhinovirus C had a significantly higher risk (HR, 1.58; 95% CI, 1.08-2.32). There was a significant interaction between virus groups and IgE sensitization on the risk of recurrent wheeze (P for interaction < .01). Only infants with both rhinovirus C infection and IgE sensitization (to food or aeroallergens) during infancy had significantly higher risks of recurrent wheeze (HR, 3.03; 95% CI, 1.20-7.61). Furthermore, compared with RSV-only, rhinovirus C infection with IgE sensitization was associated with significantly higher risks of recurrent wheeze with subsequent development of asthma at age 4 years (HR, 4.06; 95% CI, 1.17-14.1).

CONCLUSIONS AND RELEVANCE

This multicenter cohort study of infants hospitalized for bronchiolitis demonstrated between-virus differences in the risk of developing recurrent wheeze. Infants with rhinovirus C infection, along with IgE sensitization, had the highest risk. This finding was driven by the association with a subtype of recurrent wheeze: children with subsequent development of asthma.