Identifying and predicting severe bronchiolitis profiles at high risk for developing asthma: Analysis of three prospective cohorts

The severity of the first occurrence of bronchiolitis increased the risk of developing asthma symptoms

AIM

The relationship between bronchiolitis and asthma is complex. We assessed whether patients admitted to a paediatric intensive care unit (PICU) with bronchiolitis had a greater risk of developing asthma than patients admitted to a paediatric ward.

METHODS

We retrospectively included children under 1 year of age, who were hospitalised for bronchiolitis for the first time at the University Hospital of Caen, France, between 2010 and 2014. The children were divided into two groups: 89 were admitted to the paediatric ward and 89 were admitted to the PICU. We wanted to assess which group developed more asthma before 6 years of age. The Global Initiative for Asthma definition was used.

RESULTS

The median age of the 178 children (55% boys) was 32 (interquartile range 19-56) days. We found that 35% of the PICU group and 19% of the ward group had asthma at 6 years of age. The mean onset of symptoms was 3 years earlier in the PICU group than the ward group (p < 0.01). Both these findings were significant.

CONCLUSION

The severity of the first episode of bronchiolitis increased the risk of developing asthma symptoms. Regular follow-ups are suggested for infants admitted to PICUs for bronchiolitis.

Early-life pneumonia and subsequent risk of respiratory disease among commercial-insured and medicaid-insured children with and without high-risk conditions

BACKGROUND

Evidence suggests that early-life community-acquired pneumonia (CAP) among healthy children increases their risk of subsequent chronic respiratory disorders. This study extends prior research by including children with and without comorbidities and conducting analyses using two databases.

METHODS

Data were obtained from the Optum Electronic Health Record Database (commercial subset) and Merative Medicaid Multi-State Database. Study populations comprised children hospitalized for CAP before age 2 years ("CAP patients") as well as matched "comparison patients." Rates of study outcomes-including chronic respiratory disease (CRD), reactive airway disease (RAD), CAP hospitalization-from age 2-5 years were calculated for CAP/comparison patients in each study population, overall and by comorbidity profile.

FINDINGS

Rates of study outcomes from age 2-5 years were markedly higher among CAP (vs. comparison) patients in commercial-insured and Medicaid-insured populations, by: 1·9 and 1·5 for CRD; 2·5 and 2·0 for RAD; 6·4 and 7·3 for CAP hospitalization. CAP patients with (vs. without) comorbidities had numerically higher rates of outcomes, but relative rates of outcomes for CAP (vs. comparison) patients were largely comparable irrespective of comorbidity profile.

INTERPRETATION

CAP before age 2 years is associated with increased rates of CRD from age 2-5 years and the proportion of children with subsequent CRD is highest among those with comorbidities. These observations suggest a potential causative role for early-life CAP in subsequent CRD.

Epigenome-Wide Association Study of Asthma Exacerbations in Europeans

BACKGROUND

Asthma exacerbations (AEs) represent the major contributor to the global asthma burden. Although genetic and environmental factors have been associated with AEs, the role of epigenetics remains uncovered.

OBJECTIVE

This study aimed to identify whole blood DNA methylation (DNAm) markers associated with AEs in Europeans.

METHODS

DNAm was assessed in 406 blood samples from Spanish individuals using the Infinium MethylationEPIC microarray (Illumina). An epigenome-wide association study was conducted to test the association of DNAm with AEs at differentially methylated positions, regions, and epigenetic modules. CpGs suggestively associated with AEs (false discovery rate [FDR] < 0.1) were followed up for replication in 222 European individuals, and the genome-wide significance (p < 9 × 10-8) was declared after meta-analyzing the discovery and replication samples. Additional assessment was performed using nasal tissue DNAm data from 155 Spanish individuals. The effects of genetic variation on DNAm were assessed through cis-methylation quantitative trait loci (meQTL) analysis. Enrichment analyses of previous EWAS signals were conducted.

RESULTS

Four CpGs were associated with AEs, and two were replicated and reached genomic significance in the meta-analysis (annotated to ZBTB16 and BAIAP2). Of those, CpG cg25345365 (ZBTB16) was cross-tissue validated in nasal epithelium (p= 0.003) and associated with five independent meQTLs (FDR < 0.05). Additionally, four differentially methylated regions and one module were significantly associated with AEs. Enrichment analyses revealed an overrepresentation of prior epigenetic associations with prenatal and environmental exposures, immune-mediated diseases, and mortality.

CONCLUSIONS

DNAm in whole blood and nasal samples may contribute to AEs in Europeans, capturing genetic and environmental risk factors.

Patterns of Use of β-2 Agonists, Steroids, and Mucoactive Medications to Treat Bronchiolitis in the PICU: U.S. Pediatric Health Information System 2009-2022 Database Study

OBJECTIVES

Describe β2-agonists, steroids, hypertonic saline (HTS), n-acetylcysteine (NAC), and dornase alfa (DA) use to treat bronchiolitis, factors associated with use, and associations between use and PICU length of stay (LOS).

DESIGN

Retrospective, multicenter cohort study.

SETTING

PICUs in the Pediatric Health Information System database.

PATIENTS

PICU admitted children 24 months young or younger with bronchiolitis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We analyzed 47,520 hospitalizations between July 1, 2018, and June 30, 2022. We calculated the rate of medication use overall and the median (range) rate for each hospital: β2-agonist (24,984/47,520 [52.6%]; median hospital, 51.7% [21.4-81.7%]), steroid (15,878/47,520 [33.4%]; median hospital, 33.4% [6.0-54.8%]), HTS (7,041/47,520 [14.8%]; median hospital, 10.5% [0-66.1%]), NAC (1,571/47,520 [3.3%]; median hospital, 0.8% [0-22.0%], and DA (840/47,520 [1.8%]; median hospital, 1.4% [0-13.6%]). Logistic regression using generalized estimating equations (GEEs) identified associations between concurrent asthma and β2-agonist (adjusted odds ratio [aOR], 8.68; 95% CI, 7.08-10.65; p < 0.001) and steroid (aOR, 10.10; 95% CI, 8.84-11.53; p < 0.001) use. Mechanical ventilation was associated with all medications: β2-agonists (aOR, 1.79; 95% CI, 1.57-2.04; p < 0.001), steroids (aOR, 2.33; 95% CI, 1.69-3.21; p < 0.001), HTS (aOR, 1.82; 95% CI, 1.47-2.25; p < 0.001), NAC (aOR, 3.29; 95% CI, 2.15-5.03; p < 0.001), and DA (aOR, 7.65; 95% CI, 4.30-13.61; p < 0.001). No medication was associated with decreased PICU LOS. To assess changes in medication use over time and associations with the 2014 American Academy of Pediatrics bronchiolitis guidelines, we expanded our analysis to 83,820 hospitalizations between July 1, 2009, and June 30, 2022. Logistic regression with GEEs found no change in β2-agonist use; steroid use increased after guideline publication (aOR, 1.05; 95% CI, 1.01-1.10; p = 0.02), HTS use changed from increasing prior to the guidelines (aOR, 1.32; 95% CI, 1.11-1.56; p = 0.001) to stable since guideline publication (aOR, 0.93; 95% CI, 0.81-1.07; p = 0.33).

CONCLUSIONS

β2-agonists, steroids, and HTS are commonly, but variably used for PICU bronchiolitis treatment. Medication use appears relatively stable over the last decade.

Drivers of Bronchodilator Use in Bronchiolitis: Analyzing Treatment Trends From Pediatric Emergency Department Practices

OBJECTIVES

This study aims to evaluate patient characteristics associated with bronchodilator (BD) use at various stages of bronchiolitis illness and evaluate corresponding patient outcomes in the emergency department (ED).

METHODS

This retrospective, cross-sectional study involves secondary data analysis from a sample of 932 children ages 3 to 24 months who received a diagnosis of bronchiolitis during an ED visit (1057 cases). Predictor variables included demographics, past medical history, family history, physical findings, medication use, and disposition. Outcomes included BD use for bronchiolitis symptoms in the pre-ED and ED settings, and associated care outcomes in the ED. Predictors of BD use in the ED with statistical significance were incorporated in a predictive multivariable logistic regression model with a training-validation split of 70% to 30%.

RESULTS

Children with prior BD use were significantly more likely than children without such history to receive BD treatment during their current bronchiolitis illness before the ED [odds ratio (OR): 23.7, 95% CI: 14.4-39], in the ED (OR: 2.6, 95% CI: 1.76-3.77), and as a prescription upon discharge from the ED (OR: 3.7, 95% CI: 2.49-5.58). In multivariable regression analyses, older age, parental asthma history, and wheezes and retractions on ED physical examination were significantly associated with BD use in the ED (P<0.05). The area under the curve for the validation model with these variables was 0.826 (95% CI: 0.794-0.858).

CONCLUSIONS

Prior BD use was associated with subsequent use during the current illness, during ED care, and subsequent prescription, forming a cyclical pattern. A perceived bronchospastic phenotype of bronchiolitis may influence clinical practice in ED settings.

Integrated nasopharyngeal airway metagenome and asthma genetic risk endotyping of severe bronchiolitis in infancy and risk of childhood asthma

BACKGROUND

Infants with bronchiolitis are at increased risk of developing asthma. Growing evidence suggests bronchiolitis is a heterogeneous condition. However, little is known about its biologically distinct subgroups based on the integrated metagenome and asthma genetic risk signature and their longitudinal relationships with asthma development.

METHODS

In a multicentre prospective cohort study of infants with severe bronchiolitis (i.e. bronchiolitis requiring hospitalisation), we profiled nasopharyngeal airway metagenome and virus at hospitalisation, and calculated the polygenic risk score of asthma. Using similarity network fusion clustering approach, we identified integrated metagenome-asthma genetic risk endotypes. In addition, we examined their longitudinal association with the risk of developing asthma by the age of 6 years.

RESULTS

Out of 450 infants with bronchiolitis (median age 3 months), we identified five distinct endotypes, characterised by their nasopharyngeal metagenome, virus and asthma genetic risk profiles. Compared with endotype A infants (who clinically resembled "classic" bronchiolitis), endotype E infants (characterised by a high abundance of Haemophilus influenzae, high proportion of rhinovirus (RV)-A and RV-C infections and high asthma genetic risk) had a significantly higher risk of developing asthma (16.7% versus 35.9%; adjusted OR 2.24, 95% CI 1.02-4.97; p=0.046). The pathway analysis showed that endotype E had enriched microbial pathways (e.g. glycolysis, l-lysine, arginine metabolism) and host pathways (e.g. interferons, interleukin-6/Janus kinase/signal transducers and activators of transcription-3, fatty acids, major histocompatibility complex and immunoglobin-related) (false discovery rate (FDR)<0.05). Additionally, endotype E had a significantly higher proportion of neutrophils (FDR<0.05).

CONCLUSION

In this multicentre prospective cohort study of infant bronchiolitis, the clustering analysis of integrated-omics data identified biologically distinct endotypes with differential risks of developing asthma.

New paradigms in acute viral bronchiolitis: Is it time to change our approach?

Viral bronchiolitis is the most common pediatric acute respiratory infection leading to hospitalization, and it causes a significant healthcare burden worldwide. Current guidelines recommend supportive management after many clinical trials on specific therapies failed to demonstrate benefits. However, several studies in the past decade have revealed that bronchiolitis may not be a homogeneous disease, but instead may constitute an umbrella comprised of different "endotypes" and "phenotypes" based on patient characteristics, etiology, pathophysiological mechanisms, and clinical presentation. In this extensive review, we summarize the current evidence that several different types of bronchiolitis ("bronchiolitides") coexist, with different short- and long-term consequences on respiratory health and the risk of asthma development. Disease pathobiology, immune response, and clinical characteristics may differ between the two most prevalent viral agents, respiratory syncytial virus and rhinovirus. Recent randomized trials have shown that some subgroups of children may benefit from the use of systemic corticosteroids and/or bronchodilators. These findings also suggest that some children may benefit from individualized therapeutical approaches for viral bronchiolitis rather than following broad recommendations for treating all patients uniformly using only supportive management.

Infant Bronchiolitis Endotypes and the Risk of Developing Childhood Asthma: Lessons From Cohort Studies

Severe bronchiolitis (i.e., bronchiolitis requiring hospitalization) during infancy is a heterogeneous condition associated with a high risk of developing childhood asthma. Yet, the exact mechanisms underlying the bronchiolitis-asthma link remain uncertain. Birth cohort studies have reported this association at the population level, including only small groups of patients with a history of bronchiolitis, and have attempted to identify the underlying biological mechanisms. Although this evidence has provided valuable insights, there are still unanswered questions regarding severe bronchiolitis-asthma pathogenesis. Recently, a few bronchiolitis cohort studies have attempted to answer these questions by applying unbiased analytical approaches to biological data. These cohort studies have identified novel bronchiolitis subtypes (i.e., endotypes) at high risk for asthma development, representing essential and enlightening evidence. For example, one distinct severe respiratory syncytial virus (RSV) bronchiolitis endotype is characterized by the presence of Moraxella catarrhalis and Streptococcus pneumoniae, higher levels of type I/II IFN expression, and changes in carbohydrate metabolism in nasal airway samples, and is associated with a high risk for childhood asthma development. Although these findings hold significance for the design of future studies that focus on childhood asthma prevention, they require validation. However, this scoping review puts the above findings into clinical context and emphasizes the significance of future research in this area aiming to offer new bronchiolitis treatments and contribute to asthma prevention.

Determinants of immunoglobulin G responses to respiratory syncytial virus and rhinovirus in children and adults

Introduction

Exposure to respiratory viruses is a significant cause of morbidity and affects virus-specific antibody levels. Little is known about determinants associated with immune response to these viruses. We aimed to investigate the determinants of respiratory syncytial virus (RSV)- and rhinovirus (RV)- specific IgG responses in both children and adults.

Methods

The study is based on the EGEA cohort, composed of 530 samples of children in EGEA1 (1991-95) and 1241 samples of adults in EGEA2 (2003-07). Cumulative RV-specific IgG levels (species A, B and C) and IgG levels to RSV-G protein were measured by using micro-array technoloy. Multiple linear mixed models (random effect to account for familial dependence) were performed to assess associations between age, sex, body mass index (BMI), tobacco smoke exposure and season of blood sampling with RSV-and RV-specific IgG levels.

Results

In children (11.1 ± 2.8 years old, 57% boys), higher RV-specific IgG levels were associated with older age (only for RV-B), female sex and lower BMI, while only older age was associated with higher RSV-specific IgG levels. In adults (43.5 ± 16.7 years old, 48% men), younger age, female sex, lower BMI, active smoking and all seasons except summer were associated with higher RV-specific IgG levels. Older age, active smoking and all seasons except summer were associated with higher RSV-specific IgG levels.

Conclusion

Personal and seasonal determinants of RSV- and RV-specific IgG levels seem to vary according to the respiratory virus type and between children and adults, suggesting different patterns of responses along the life course.

Association of respiratory virus types with clinical features in bronchiolitis: Implications for virus testing strategies. A systematic review and meta-analysis

BACKGROUND

Bronchiolitis is a leading cause of infant hospitalization, linked to respiratory syncytial virus (RSV) and rhinovirus (RV). Guidelines lack specific viral testing for bronchiolitis management. To establish effective management strategies, it is crucial to assess whether specific respiratory virus types are correlated with distinct examination features.

METHODS

Through a systematic search of three databases, 21 studies were qualitatively analyzed, with 18 used for meta-analysis. Various outcomes like wheezing on auscultation, fever, atopic traits, and infection severity were evaluated.

RESULTS

RSV-positive bronchiolitis was associated with a higher need for oxygen supplementation (OR 1.78, 95% CI 1.04-3.02) in 5 studies, while RV-positive bronchiolitis was more frequently linked to personal history of eczema (OR 0.60, 95% CI 0.41-0.88) in 6 studies. No significant differences were observed in the other outcomes examined.

CONCLUSIONS

Bronchiolitis caused by RSV or RV presents with similar clinical features. Despite the associations between RSV-positive bronchiolitis and need for oxygen supplementation, and RV-positive bronchiolitis and a history of eczema, our study shows that viral etiology of bronchiolitis cannot be determined solely based on clinical presentation. Tailored management strategies, informed by accurate viral testing, seem crucial in clinical practice for enhancing patient outcomes in severe bronchiolitis.

Air pollution after acute bronchiolitis is a risk factor for preschool asthma: a nested case-control study

BACKGROUND

Acute bronchiolitis and air pollution are both risk factor of pediatric asthma. This study aimed to assess subsequent exposure to air pollutants related to the inception of preschool asthma in infants with acute bronchiolitis. This study aimed to assess subsequent exposure to air pollutants related to the inception of preschool asthma in infants with acute bronchiolitis.

METHODS

A nested case-control retrospective study was performed at the Kaohsiung Medical University Hospital systems between 2009 and 2019. The average concentration of PM10, PM2.5, SO2, NO, NO2, and NOX was collected for three, six, and twelve months after the first infected episode. Adjusted regression models were employed to evaluate the association between asthma and air pollution exposure after bronchiolitis.

RESULTS

Two thousand six hundred thirty-seven children with acute bronchiolitis were included. Exposure to PM10, PM2.5, SO2, NO, NO2, and NOX in the three, six, and twelve months following an episode of bronchiolitis was found to significantly increase the risk of preschool asthma in infants with a history of bronchiolitis.(OR, 95%CI: PM10 = 1.517-1.559, 1.354-1.744; PM2.5 = 2.510-2.603, 2.148-3.061; SO2 = 1.970-2.040, 1.724-2.342; ; NO = 1.915-1.950, 1.647-2.272; NO2 = 1.915-1.950, 1.647-2.272; NOX = 1.752-1.970, 1.508-2.252) In a sensitive analysis of hospitalized infants, only PM10, PM2.5, SO2, and NO were found to have significant effects during all time periods. (OR, 95%CI: PM10 = 1.613-1.650, 1.240-2.140; PM2.5 = 2.208-2.286, 1.568-3.061; SO2 = 1.679-1.622, 1.197-2.292; NO = 1.525-1.557, 1.094-2.181) CONCLUSION: The presence of ambient PM10, PM2.5, SO2 and NO in the three, six, and twelve months following an episode of acute bronchiolitis has been linked to the development of preschool asthma in infants with a history of acute bronchiolitis.

Bronchiolitis, Regardless of Its Etiology and Severity, Is Associated With Increased Risk of Asthma: A Population-Based Study

An association exists between severe respiratory syncytial virus (RSV)-bronchiolitis and a subsequent increased risk of recurrent wheezing (RW) and asthma. However, a causal relationship remains unproven. Using a retrospective population-based cohort study (339 814 children), bronchiolitis during the first 2 years of life (regardless of etiology and severity) was associated with at least a 3-fold increased risk of RW/asthma at 2-4 years and an increased prevalence of asthma at ≥5 years of age. The risk was similar in children with mild bronchiolitis as in those with hospitalized RSV-bronchiolitis and was higher in children with hospitalized non-RSV-bronchiolitis. The rate of RW/asthma was higher when bronchiolitis occurred after the first 6 months of life. Our results seem to support the hypothesis of a shared predisposition to bronchiolitis (irrespective of etiology) and RW/asthma. However, 60% of hospitalized bronchiolitis cases in our setting are due to RSV, which should be paramount in decision-making on imminent RSV prevention strategies.

Immunoglobulin E-virus phenotypes of infant bronchiolitis and risk of childhood asthma

Background

Bronchiolitis is the leading cause of infant hospitalization in U.S. and is associated with increased risk for childhood asthma. Immunoglobulin E (IgE) not only plays major roles in antiviral immune responses and atopic predisposition, but also offers a potential therapeutic target.

Objective

We aimed to identify phenotypes of infant bronchiolitis by using total IgE (tIgE) and virus data, to determine their association with asthma development, and examine their biological characteristics.

Methods

In a multicenter prospective cohort study of 1,016 infants (age <1 year) hospitalized for bronchiolitis, we applied clustering approaches to identify phenotypes by integrating tIgE and virus (respiratory syncytial virus [RSV], rhinovirus [RV]) data at hospitalization. We examined their longitudinal association with the risk of developing asthma by age 6 years and investigated their biological characteristics by integrating the upper airway mRNA and microRNA data in a subset (n=182).

Results

In infants hospitalized for bronchiolitis, we identified 4 phenotypes: 1) tIgE^lowvirus^RSV-high, 2) tIgE^lowvirus^RSV-low/RV, 3) tIgE^highvirus^RSV-high, and 4) tIgE^highvirus^RSV-low/RV phenotypes. Compared to phenotype 1 infants (resembling "classic" bronchiolitis), phenotype 4 infants (tIgE^highvirus^RSV-low/RV) had a significantly higher risk for developing asthma (19% vs. 43%; adjOR, 2.93; 95% CI, 1.02-8.43; P=.046). Phenotypes 3 and 4 (tIgE^high) had depleted type I interferon and enriched antigen presentation pathways; phenotype 4 also had depleted airway epithelium structure pathways.

Conclusions

In this multicenter cohort, tIgE-virus clustering identified distinct phenotypes of infant bronchiolitis with differential risks of asthma development and unique biological characteristics.

Severe bronchiolitis profiling as the first step towards prevention of asthma

Bronchiolitis is the most common respiratory infection leading to hospitalization and constitutes a significant healthcare burden. The two main viral agents causing bronchiolitis, respiratory syncytial virus (RSV) and rhinovirus (RV), have distinct cytopathic, immune response, and clinical characteristics. Different approaches have been suggested for subtyping bronchiolitis based on viral etiology, atopic status, transcriptome profiles in blood, airway metabolome, lipidomic data, and airway microbiota. The highest risk of asthma at school age has been in a subgroup of bronchiolitis characterized by older age, high prevalence of RV infection, previous breathing problems, and/or eczema. Regarding solely viral etiology, RV-bronchiolitis in infancy has been linked to a nearly three times higher risk of developing asthma than RSV-bronchiolitis. Although treatment with betamimetics and systemic corticosteroids has been found ineffective in bronchiolitis overall, it can be beneficial for infants with severe RV bronchiolitis. Thus, there is a need to develop a more individualized therapeutic approach for bronchiolitis and follow-up strategies for infants at higher risk of asthma in the future perspective.

"Liquid biopsy" - extracellular vesicles as potential novel players towards precision medicine in asthma

Extracellular vesicles (EVs) have emerged as vital mediators in intracellular communication in the lung microenvironment. Environmental exposure to various triggers (e.g., viruses, allergens) stimulates the EV-mediated cascade of pro-inflammatory responses that play a key role in the asthma pathomechanism. This complex EV-mediated crosstalk in the asthmatic lung microenvironment occurs between different cell types, including airway epithelial cells and immune cells. The cargo composition of EVs mirrors hereby the type and activation status of the parent cell. Therefore, EVs collected in a noninvasive way (e.g., in nasal lavage, serum) could inform on the disease status as a "liquid biopsy", which is particularly important in the pediatric population. As a heterogeneous disease, asthma with its distinct endotypes and phenotypes requires more investigation to develop novel diagnostics and personalized case management. Filling these knowledge gaps may be facilitated by further EV research. Here, we summarize the contribution of EVs in the lung microenvironment as potential novel players towards precision medicine in the development of asthma. Although rapidly evolving, the EV field is still in its infancy. However, it is expected that a better understanding of the role of EVs in the asthma pathomechanism will open up new horizons for precision medicine diagnostic and therapeutic solutions.

Nasopharyngeal lipidomic endotypes of infants with bronchiolitis and risk of childhood asthma: a multicentre prospective study

BACKGROUND

Bronchiolitis is the leading cause of hospitalisation of US infants and an important risk factor for childhood asthma. Recent evidence suggests that bronchiolitis is clinically heterogeneous. We sought to derive bronchiolitis endotypes by integrating clinical, virus and lipidomics data and to examine their relationship with subsequent asthma risk.

METHODS

This is a multicentre prospective cohort study of infants (age <12 months) hospitalised for bronchiolitis. We identified endotypes by applying clustering approaches to clinical, virus and nasopharyngeal airway lipidomic data measured at hospitalisation. We then determined their longitudinal association with the risk for developing asthma by age 6 years by fitting a mixed-effects logistic regression model. To account for multiple comparisons of the lipidomics data, we computed the false discovery rate (FDR). To understand the underlying biological mechanism of the endotypes, we also applied pathway analyses to the lipidomics data.

RESULTS

Of 917 infants with bronchiolitis (median age, 3 months), we identified clinically and biologically meaningful lipidomic endotypes: (A) cinicalclassiclipidmixed (n=263), (B) clinicalseverelipidsphingolipids-high (n=281), (C) clinicalmoderatelipidphospholipids-high (n=212) and (D) clinicalatopiclipidsphingolipids-low (n=161). Endotype A infants were characterised by 'classic' clinical presentation of bronchiolitis. Profile D infants were characterised by a higher proportion of parental asthma, IgE sensitisation and rhinovirus infection and low sphingolipids (eg, sphingomyelins, ceramides). Compared with endotype A, profile D infants had a significantly higher risk of asthma (22% vs 50%; unadjusted OR, 3.60; 95% CI 2.31 to 5.62; p<0.001). Additionally, endotype D had a significantly lower abundance of polyunsaturated fatty acids (eg, docosahexaenoic acid; FDR=0.01). The pathway analysis revealed that sphingolipid metabolism pathway was differentially expressed in endotype D (FDR=0.048).

CONCLUSIONS

In this multicentre prospective cohort study of infants with bronchiolitis, integrated clustering of clinical, virus and lipidomic data identified clinically and biologically distinct endotypes that have a significantly differential risk for developing asthma.Delete.

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.

Respiratory virus type to guide predictive enrichment approaches in the management of the first episode of bronchiolitis: A systematic review

It has become clear that severe bronchiolitis is a heterogeneous disease; even so, current bronchiolitis management guidelines rely on the one-size-fits-all approach regarding achieving both short-term and chronic outcomes. It has been speculated that the use of molecular markers could guide more effective pharmacological management and achieve the prevention of chronic respiratory sequelae. Existing data suggest that asthma-like treatment (systemic corticosteroids and beta2-agonists) in infants with rhinovirus-induced bronchiolitis is associated with improved short-term and chronic outcomes, but robust data is still lacking. We performed a systematic search of PubMed, Embase, Web of Science, and the Cochrane’s Library to identify eligible randomized controlled trials to determine the efficacy of a personalized, virus-dependent application of systemic corticosteroids in children with severe bronchiolitis. Twelve studies with heterogeneous methodology were included. The analysis of the available results comparing the respiratory syncytial virus (RSV)-positive and RSV-negative children did not reveal significant differences in the associatons between systemic corticosteroid use in acute episode and duration of hospitalization (short-term outcome). However, this systematic review identified a trend of the positive association between the use of systematic corticosteroids and duration of hospitalization in RSV-negative infants hospitalized with the first episode of bronchiolitis (two studies). This evidence is not conclusive. Taken together, we suggest the design for future studies to assess the respiratory virus type in guiding predictive enrichment approaches in infants presenting with the first episode of bronchiolitis.

Bronchiolitis therapies and misadventures

Viral bronchiolitis, which is most commonly caused by an infection with the respiratory syncytial virus (RSV), can lead to respiratory difficulties in young children which may require hospitalization. Despite years of research and medical trials, the mainstay of bronchiolitis treatment remains supportive only. This review provides an overview of the history of different treatments for bronchiolitis, including those that failed, as well as new therapies that are under study. Future studies for the treatment of bronchiolitis should consider different age-groups, important subgroups (i.e., those with a prior history of wheezing, those with a family history of asthma and those with non-RSV viral etiologies) whose response to treatment may differ from that of the composite group.

Web-based application for predicting the potential target phenotype for recombinant human thrombomodulin therapy in patients with sepsis: analysis of three multicentre registries

A recent randomised controlled trial failed to demonstrate a beneficial effect of recombinant human thrombomodulin (rhTM) on sepsis. However, there is still controversy in the effects of rhTM for sepsis due to the heterogeneity of the study population. We previously identified patients with a distinct phenotype that could be a potential target of rhTM therapy (rhTM target phenotype). However, for application in the clinical setting, a simple tool for determining this target is necessary. Thus, using three multicentre sepsis registries, we aimed to develop and validate a machine learning model for predicting presence of the target phenotype that we previously identified for targeted rhTM therapy. The predictors were platelet count, PT-INR, fibrinogen, fibrinogen/fibrin degradation products, and D-dimer. We also implemented the model as a web-based application. Two of the three registries were used for model development (n = 3694), and the remaining registry was used for validation (n = 1184). Approximately 8-9% of patients had the rhTM target phenotype in each cohort. In the validation, the C statistic of the developed model for predicting the rhTM target phenotype was 0.996 (95% CI 0.993-0.998), with a sensitivity of 0.991 and a specificity of 0.967. Among patients who were predicted to have the potential target phenotype (predicted target patients) in the validation cohort (n = 142), rhTM use was associated with a lower in-hospital mortality (adjusted risk difference, - 31.3% [- 53.5 to - 9.1%]). The developed model was able to accurately predict the rhTM target phenotype. The model, which is available as a web-based application, could profoundly benefit clinicians and researchers investigating the heterogeneity in the treatment effects of rhTM and its mechanisms.