Background Rhinovirus (RV) has been linked to the pathogenesis of asthma. Prematurity is a risk factor for severe RV infection in early life, but is unknown if RV elicits enhanced pro-asthmatic airway cytokine responses in premature infants. This study investigated if young children born severely premature (<32 weeks gestation) exhibit airway secretion of Th2 and Th17 cytokines during natural RV infections and if RV-induced Th2-Th17 responses are linked to more respiratory morbidity in premature children during the first two years of life. Methods We measured Th2 and Th17 nasal airway cytokines in a retrospective cohort of young children aged 0–2 years with PCR-confirmed RV infection or non-detectable virus. Protein levels of IL-4, IL-13, TSLP and IL-17 were determined with multiplex immunoassays. Demographic and clinical variables were obtained by electronic medical record (EMR) review. Results The study comprised 214 children born full term (n=108), pre-term (n=44) or severely premature (n=62). Natural RV infection in severely premature children was associated with elevated airway secretion of Th2 (IL-4 and IL-13) and Th17 (IL-17) cytokines, particularly in subjects with history of bronchopulmonary dysplasia. Severely premature children with high RV-induced airway IL-4 had recurrent respiratory hospitalizations (median 3.65 hosp/year; IQR 2.8–4.8) and were more likely to have at least one pediatric intensive care unit admission during the first two years of life (OR 8.72; 95% CI 1.3–58.7; p=0.02). Conclusions Severely premature children have increased airway secretion of Th2 and Th17 cytokines during RV infections, which is associated with more respiratory morbidity in the first two years of life

BackgroundInnate immune responses are fine-tuned by small noncoding RNA molecules termed microRNAs (miRs) that modify gene expression in response to the environment. During acute infections, miRs can be secreted in extracellular vesicles (EV) to facilitate cell-to-cell genetic communication. The purpose of this study was to characterize the baseline population of miRs secreted in EVs in the airways of young children (airway secretory microRNAome) and examine the changes during rhinovirus (RV) infection, the most common cause of asthma exacerbations and the most important early risk factor for the development of asthma beyond childhood.MethodsNasal airway secretions were obtained from children (≤3 yrs. old) during PCR-confirmed RV infections (n = 10) and age-matched controls (n = 10). Nasal EVs were isolated with polymer-based precipitation and global miR profiles generated using NanoString microarrays. We validated our in vivo airway secretory miR data in an in vitro airway epithelium model using apical secretions from primary human bronchial epithelial cells (HBEC) differentiated at air-liquid interface (ALI). Bioinformatics tools were used to determine the unified (nasal and bronchial) signature airway secretory miRNAome and changes during RV infection in children.ResultsMultiscale analysis identified four signature miRs comprising the baseline airway secretory miRNAome: hsa-miR-630, hsa-miR-302d-3p, hsa- miR-320e, hsa-miR-612. We identified hsa-miR-155 as the main change in the baseline miRNAome during RV infection in young children. We investigated the potential biological relevance of the airway secretion of hsa-mir-155 using in silico models derived from gene datasets of experimental in vivo human RV infection. These analyses confirmed that hsa-miR-155 targetome is an overrepresented pathway in the upper airways of individuals infected with RV.ConclusionsComparative analysis of the airway secretory microRNAome in children indicates that RV infection is associated with airway secretion of EVs containing miR-155, which is predicted in silico to regulate antiviral immunity. Further characterization of the airway secretory microRNAome during health and disease may lead to completely new strategies to treat and monitor respiratory conditions in all ages.

No abstract

Rationale Human metapneumovirus (HMPV) is a recently discovered respiratory pathogen of the family Paramyxoviridae, the same of Respiratory Syncytial Virus (RSV). Premature children are at high risk of severe RSV infections, but it is unclear whether HMPV infection is more severe in hospitalized children with history of severe prematurity. Methods We conducted a retrospective analysis of the clinical respiratory presentation of all PCR-confirmed HMPV infections in preschool age children (≤5 yrs.) with and without history of severe prematurity (<32 weeks gestation). Respiratory distress scores were developed to examine the clinical severity of HMPV infections. Demographic and clinical variables were obtained from reviewing electronic medical records (EMR). Results A total of 571 pre-school children were identified by PCR-confirmed viral respiratory tract infection during the study period. HMPV was identified as a causative organism in 63 cases (11%). Fifty–eight (n=58) preschool age children with HMPV infection were included in this study after excluding those with significant co-morbidities. Our data demonstrated that 32.7% of children admitted with HMPV had history of severe prematurity. Preschool children with history of prematurity had more severe HMPV disease as illustrated by longer hospitalizations, new or increased need for supplemental O2, and higher severity scores independently of age, ethnicity and history of asthma. Conclusion Our study suggests that HMPV infection causes significant disease burden among preschool children with history of prematurity leading to severe respiratory infections and increasing health care resource utilization due to prolonged hospitalizations.

BACKGROUND It is unknown why human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) cause severe respiratory infection in children, particularly in premature infants. Our aim was to investigate if there are defective airway antiviral responses to these viruses in young children with history of prematurity. METHODS Nasal airway secretions were collected from 140 children ≤3 y old without detectable virus (n = 80) or with PCR-confirmed HMPV or RSV infection (n = 60). Nasal protein levels of IFNγ, CCL5/RANTES, IL-10, IL-4, and IL-17 were determined using a multiplex magnetic bead immunoassay. RESULTS Full-term children with HMPV and RSV infection had increased levels of nasal airway IFNγ, CCL5, and IL-10 along with an elevation in Th1 (IFNγ)/Th2 (IL-4) ratios, which is expected during antiviral responses. In contrast, HMPV-infected premature children (< 32 wk gestation) did not exhibit increased Th1/Th2 ratios or elevated nasal airway secretion of IFNγ, CCL5, and IL-10 relative to uninfected controls. CONCLUSION Our study is the first to demonstrate that premature infants have defective IFNγ, CCL5/RANTES, and IL-10 airway responses during HMPV infection and provides novel insights about the potential reason why HMPV causes severe respiratory disease in children with history of prematurity.

BackgroundThymic stromal lymphoproetin (TSLP) is a cytokine secreted by the airway epithelium in response to respiratory viruses and it is known to promote allergic Th2 responses in asthma. This study investigated whether virally-induced secretion of TSLP is directional in nature (apical vs. basolateral) and/or if there are TSLP-mediated effects occurring at both sides of the bronchial epithelial barrier in the asthmatic state.MethodsPrimary human bronchial epithelial cells (HBEC) from control (n = 3) and asthmatic (n = 3) donors were differentiated into polarized respiratory tract epithelium under air-liquid interface (ALI) conditions and treated apically with dsRNA (viral surrogate) or TSLP. Sub-epithelial effects of TSLP were examined in human airway smooth muscle cells (HASMC) from normal (n = 3) and asthmatic (n = 3) donors. Clinical experiments examined nasal airway secretions obtained from asthmatic children during naturally occurring rhinovirus-induced exacerbations (n = 20) vs. non-asthmatic uninfected controls (n = 20). Protein levels of TSLP, CCL11/eotaxin-1, CCL17/TARC, CCL22/MDC, TNF-α and CXCL8 were determined with a multiplex magnetic bead assay.ResultsOur data demonstrate that: 1) Asthmatic HBEC exhibit an exaggerated apical, but not basal, secretion of TSLP after dsRNA exposure; 2) TSLP exposure induces unidirectional (apical) secretion of CCL11/eotaxin-1 in asthmatic HBEC and enhanced CCL11/eotaxin-1 secretion in asthmatic HASMC; 3) Rhinovirus-induced asthma exacerbations in children are associated with in vivo airway secretion of TSLP and CCL11/eotaxin-1.ConclusionsThere are virally-induced TSLP-driven secretory immune responses at both sides of the bronchial epithelial barrier characterized by enhanced CCL11/eotaxin-1 secretion in asthmatic airways. These results suggest a new model of TSLP-mediated eosinophilic responses in the asthmatic airway during viral-induced exacerbations.

ABSTRACT

Accurate assessment of severity of viral respiratory illnesses (VRIs) allows early interventions to prevent morbidity and mortality in young children. This paper proposes a novel imaging biomarker framework with chest X-ray image for assessing VRI’s severity in infants, developed specifically to meet the distinct challenges for pediatric population. The proposed framework integrates three novel technical contributions: a) lung segmentation using weighted partitioned active shape model, b) obtrusive object removal using graph cut segmentation with asymmetry constraint, and c) severity quantification using information-theoretic heterogeneity measures. This paper presents our pilot experimental results with a dataset of 148 images and the ground-truth severity scores given by a board-certified pediatric pulmonologist, demonstrating the effectiveness and clinical relevance of the presented framework.