Project description:This was a prospective observational cohort study involving a convenience sample of previously healthy children <2 years of age with acute RSV infection as well as healthy non-infected age matched controls. The study was conducted at Nationwide Children’s Hospital (NCH; Columbus, OH) during four respiratory seasons, from 2011 to 2015. Children were enrolled at the NCH urgent care clinics, the emergency department or in the inpatient ward or intensive care unit (PICU). For the inpatients enrolled at ward or PICU the median time from admission to sample collection was 21.3h (interquartile range [IQR] 16.7 -37.6h). The majority of children had a confirmatory RSV test (either rapid antigen testing or PCR based) at enrollment per standard of care. In addition, the presence of RSV was confirmed by quantitative real time (qRT)-PCR in all study subjects. Healthy age-matched controls were enrolled during well-child visits or minor elective surgical procedures not involving the respiratory tract as described [Mejias 2013]. Exclusion criteria were as follows: documented bacterial co-infections, premature birth (<36 weeks of gestation), chronic or congenital medical conditions, and immunodeficiency. For healthy controls, additional exclusion criteria included: presence of fever or symptoms of respiratory tract infection within two weeks of enrollment.
Project description:The objective of this study was to identify gene expression markers of disease severity in a cohort of RSV infected children Respiratory syncytial virus (RSV) is the number one pathogen causing lower respiratory tract infection that leads to hospitalization in young children. Despite growing insights in the disease pathogenesis, the clinical presentation in these children is highly variable and heterogeneous, and reliable markers predictive of disease progression are lacking. We characterized the host response to acute RSV infection to identify biomarkers associated with RSV disease and disease severity. Whole genome transcriptome was analysed early on the disease course in blood samples from otherwise healthy children <2 years of age, who were either hospitalized (n = 110) or evaluated as outpatients (n = 37) due to RSV infection. Age-matched non-RSV-infected healthy children (n = 51) were analysed in parallel. A clustering approach on the transcriptome data revealed biologically meaningful biomarkers associated with progression to severe RSV disease. Overall, the whole blood transcriptome pointed to alterations in frequency of specific immune cell types (neutrophils, T- and B-lymphocytes, NK cells, monocytes) in RSV-infected children. In addition, a cluster enriched for neutrophil degranulation genes, was highly correlated with clinical disease severity. The driver genes of this cluster (OLFM4, ELANE, MMP8, BPI, CEACAM8, LCN2, LTF and MPO) were selected and validated in independent existing transcriptomics datasets. We identified a set of genes involved in neutrophil degranulation as markers for RSV disease severity. Additional prospective studies using these markers are required to further confirm their value as predictive tool in routine clinical care.
Project description:Respiratory viral infections follow an unpredictable clinical course in young children ranging from a common cold to respiratory failure. The transition from mild to severe disease occurs rapidly and is difficult to predict. The pathophysiology underlying disease severity has remained elusive. There is an urgent need to better understand the immune response in this disease to come up with biomarkers that may aid clinical decision making. In a prospective study, flow cytometric and genome-wide gene expression analyses were performed on blood samples of 26 children with a diagnosis of severe, moderate or mild Respiratory Syncytial Virus (RSV) infection. Differentially expressed genes were validated using Q-PCR in a second cohort of 80 children during three consecutive winter seasons. FACS analyses were also performed in the second cohort and on recovery samples of severe cases in the first cohort. Severe RSV infection was associated with a transient but marked decrease in CD4+ T, CD8+ T, and NK cells in peripheral blood. Gene expression analyses in both cohorts identified Olfactomedin4 (OLFM4) as a fully discriminative marker between children with mild and severe RSV infection, giving a PAM cross-validation error of 0%. Patients with an OLFM4 gene expression level above -7.5 were 6 times more likely to develop severe disease, after correction for age at hospitalization and gestational age. In conclusion, by combining genome-wide expression profiling of blood cell subsets with clinically well-annotated samples, OLFM4 was identified as a biomarker for severity of pediatric RSV infection. Samples were taken of 26 patients with acute RSV infections, divided into mild (n=9), moderate (n=9) and severe (n=8) disease. From moderate and severe diseased patients recovery samples were obtained as well.
Project description:Respiratory viral infections follow an unpredictable clinical course in young children ranging from a common cold to respiratory failure. The transition from mild to severe disease occurs rapidly and is difficult to predict. The pathophysiology underlying disease severity has remained elusive. There is an urgent need to better understand the immune response in this disease to come up with biomarkers that may aid clinical decision making. In a prospective study, flow cytometric and genome-wide gene expression analyses were performed on blood samples of 26 children with a diagnosis of severe, moderate or mild Respiratory Syncytial Virus (RSV) infection. Differentially expressed genes were validated using Q-PCR in a second cohort of 80 children during three consecutive winter seasons. FACS analyses were also performed in the second cohort and on recovery samples of severe cases in the first cohort. Severe RSV infection was associated with a transient but marked decrease in CD4+ T, CD8+ T, and NK cells in peripheral blood. Gene expression analyses in both cohorts identified Olfactomedin4 (OLFM4) as a fully discriminative marker between children with mild and severe RSV infection, giving a PAM cross-validation error of 0%. Patients with an OLFM4 gene expression level above -7.5 were 6 times more likely to develop severe disease, after correction for age at hospitalization and gestational age. In conclusion, by combining genome-wide expression profiling of blood cell subsets with clinically well-annotated samples, OLFM4 was identified as a biomarker for severity of pediatric RSV infection.
Project description:<p>A prospective multi-year clinical translational study including three cohorts of term infants experiencing their first Respiratory Syncytial Virus (RSV) season. All infants are less than or equal to nine months of age at study entry. The three subject cohorts represent the full spectrum of RSV disease severity and include a birth cohort, a cohort of infants hospitalized for RSV disease and infants evaluated at ambulatory settings for RSV infection. All infants are followed longitudinally and evaluated at recognition of acute RSV infection and twice during convalescence. Innate and adaptive immune status are comprehensively measured in association with clinical, environmental, viral, and bacteriologic factors. Genome-wide expression is assessed in the nasal airways, and in sorted peripheral blood lymphocytes. The study goal is to Identify host responses to RSV infection and factors associated with severe disease. </p>
Project description:Respiratory syncytial virus (RSV) causes severe disease mostly in infants; however, mechanisms of age association remain elusive. Here, employing human bronchial epithelium models generated from tracheal aspirate-derived basal stem cells of neonates and adults, we investigate whether age regulates RSV-epithelium interaction to determine disease severity. We show that following RSV infection, only neonatal epithelium model exhibits cytopathy and mucus hyperplasia, and neonatal epithelium has more robust viral spread and inflammatory responses than adult epithelium. Mechanistically, RSV-infected neonatal ciliated cells display age-related impairment of STAT3 activation, rendering susceptibility to apoptosis, which facilitates viral spread. In contrast, SARS-CoV-2 infection of ciliated cells has no effect on STAT3 activation and is not affected by age. Taken together, our findings identify an age-related and RSV-specific interaction with neonatal bronchial epithelium that critically contributes to severity of infection, and STAT3 activation offers a potential strategy to battle severe RSV disease in infants.
Project description:Rationale: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and hospitalizations in infants worldwide. Known risk factors, however, incompletely explain the variability of RSV disease severity among children. We postulate that severity of RSV infection is influenced in part by modulation of the host immune response by the local microbial ecosystem at the time of infection. Objectives: To define whether different nasopharyngeal microbiota profiles are associated with distinct host transcriptome profiles and severity in children with RSV infection. Methods: We analyzed the nasopharyngeal microbiota profiles of young children with mild and severe RSV disease and healthy matched controls by 16S-rRNA sequencing. In parallel, we analyzed whole blood gene expression profiles to study the relationship between microbial community composition, the RSV-induced host transcriptional response and clinical disease severity. Measurements and Main results: We identified five nasopharyngeal microbiota profiles characterized by enrichment of H. influenzae, Streptococcus, Corynebacterium, Moraxella or S. aureus. RSV infection and RSV hospitalization were positively associated with H. influenzae and Streptococcus, and negatively associated with S. aureus abundance, independent of age. The host response to RSV was defined by overexpression of interferon-related genes, and this was independent of the microbiota composition. On the other hand, transcriptome profiles of RSV infected children with H. influenzae and Streptococcus-dominated microbiota were characterized by greater overexpression of genes linked to toll-like receptor-signaling and neutrophil activation and were more frequently hospitalized Conclusions: Our data suggest an immunomodulatory role for the resident nasopharyngeal microbial community early in RSV infection, potentially affecting RSV disease severity.
Project description:Respiratory Syncytial virus (RSV) is the most common cause of childhood viral bronchiolitis and lung injury. Inflammatory responses significantly contribute to lung pathologies during RSV infections and bronchiolitis but the exact mechanisms have not been completely defined. The double-stranded RNA-activated protein kinase (PKR) functions to inhibit viral replication and participates in several signaling pathways associated with innate inflammatory immune responses. Using a functionally defective PKR (PKR-/-) mouse model, we investigated the role of this kinase in early events of RSV-induced inflammation. Our data showed that bronchoalveolar lavage (BAL) fluid of infected PKR-/- mice had significantly lower levels of several innate inflammatory cytokines and chemokines. Histological examinations revealed that there was less lung injury in infected PKR-/- mice as compared to the wild type. A genome-wide analysis showed that several early anti viral and immune regulatory genes were affected by PKR activation. These data suggest that PKR is a signaling molecule for immune responses during RSV infections.
Project description:Background: There is limited data on how different RSV genotypes and associated viral loads influence disease phenotypes. We characterized the genetic variability of RSV strains during five non-consecutive respiratory seasons, and evaluated the role of RSV subtypes, genotypes and viral loads on clinical disease severity. Methods: Healthy infants hospitalized with RSV bronchiolitis were prospectively enrolled and nasopharyngeal samples obtained within 24h of hospitalization for RSV load quantitation by PCR, typing and genotyping. Parameters of disease severity were assessed, and multivariate models constructed to identify virologic and clinical factors predictive of clinical outcomes. Results: From March 2004 to April 2011, we enrolled 253 patients (56.5 % males; median age 2.1 (1.1-4.0) months). RSV A infections predominated over RSV B (69% vs. 31%; p<0.001) and showed greater genotype variability. The most common genotypes were RSV A/GA2, A/GA5 and RSV B/BA. Infants infected with RSV GA5 had higher viral loads compared with GA2 or BA infection (p<0.01), independent of duration of symptoms. After adjusting for other covariates, RSV A/GA5 infections were associated with longer hospital stay. Conclusions: RSV A infections were more frequent than RSV B infections and displayed greater genetic variability. Infections with GA5 were independently associated with clinical disease severity.
Project description:Lower respiratory tract infections (LRTI) from human Respiratory Syncytial Virus (RSV) are a significant cause of morbidity in children. A component of LRTI pathogenesis is due to signals generated by infected lower airway cells that alter lymphocyte populations and trigger airway remodeling. To obtain insights into this process, we applied an unbiased quantitative proteomics analysis of the RSV-induced epithelial secretory response in cells representative of the trachea (hBECs) vs small airway bronchiolar cells (hSAECs). A workflow was standardized initially using telomerase immortalized human epithelial cells that showed high reproducibility and cell-type differences in proteomic signatures of both secreted proteins and isolated nanoparticles (exosomes). Over half of secretome proteins were contained within exosomal, with the remainder originating from lysosomal and vaculolar compartments. We applied this workflow to three independently derived primary human cultures. 577 differentially expressed proteins from control supernatants and 966 differentially expressed proteins from RSV-infected cell supernatants were identified at a 1% false discovery rate (FDR). 15 proteins were unique to RSV-infected hBECs regulated by epithelial-specific ets homology factor (EHF). 106 proteins were unique to RSV-infected hSAECs enriched in proteins regulated by the NFB transcription factor. In this latter group, we independently validated the differential expression of Chemokine (C-C Motif) Ligand 20 (CCL20)/macrophage inducible protein (MIP)3, Thymic Stromal Lymphopoietin (TSLP) and chemokine (CC) ligand 3-like 1(CCL3-L1). CCL20/MIP3 is the most active mucin inducing factor in the RSV infected hSAEC secretome, and is differentially expressed in smaller airways in a mouse model of RSV infection. These studies provide insight into role of exosomal production in innate responses and regional differences in epithelial secretomes that participate in pathogenesis of RSV LRTI-induced airway remodeling.