Nasosorption as a Minimally Invasive Sampling Procedure: Mucosal Viral Load and Inflammation in Primary RSV Bronchiolitis

The role of respiratory syncytial virus G protein in immune cell infection and pathogenesis

Severe respiratory syncytial virus (RSV) disease is a significant contributor to the global burden of disease in infants and children. The RSV attachment protein (G) has been shown to be critical in invading airway epithelial cells through its CX3C motif interacting with the host receptor CX3CR1. The ubiquitous expression of this receptor on immune cells may explain their susceptibility to RSV infection. The RSV G protein may enhance disease severity through reprogramming of normal cellular functionality leading to inhibition of antiviral responses. While existing preventives targeting the RSV fusion (F) protein are highly effective, there are no RSV therapeutics based on the G protein to limit RSV pathogenesis. Monoclonal antibodies targeting the RSV G protein administered as post-infection therapeutics in mice have been shown to improve the antiviral response, reduce viral load and limit disease severity. Further research is required to better understand how RSV infection of immune cells contributes to pathogenesis for the development of more targeted and efficacious therapeutics.

Viral load in hospitalized infants with respiratory syncytial virus bronchiolitis: a three-way comparative analysis

Viral load measurement of Respiratory syncytial virus (RSV) in acute bronchiolitis depends on specimen collection, viral load quantification, and transport media. The aim of this study was to investigate viral load in three-way-comparative analyses; nasal swab versus nasal wash, quantitative real-time polymerase chain reaction (RT-PCR) versus cell tissue culture, and various transport media. A prospective cohort study of infants aged < 12 months, admitted to the Soroka Medical Center, due to acute bronchiolitis, was conducted. Two nasal swabs and two nasal wash samples (in UTM and VCM) were collected from each infant upon admission and after 48 h. Samples were immediately stored at -80 °C and tested at Viroclinics DDL (Rotterdam, Netherlands). Quantitative RT-PCR and quantitative virus culture were performed using tissue culture infective dose (TCID50). Spearman's correlation coefficient test assessed the correlation between the different methods, viral load, and clinical severity score. One hundred samples were collected from 13 infants (mean age 5.7 ± 3.8 months, 46% males). Twelve patients were RSV-A positive, and one was RSV-B positive. A high correlation was found between transport media- UTM and VCM (0.92, P < 0.001) and between nasal swabs and nasal wash samples (0.62, P = 0.02). RSV signals were higher in nasal wash than in swabs. PCR signals were lower in the second collection compared to the first. No correlation was found between viral load and clinical severity.    Conclusion: RSV viral load is comparable across nasal wash, nasal swabs, and various transport media. However, it did not correlate with clinical severity, probably due to the limited sample size. Broader analyses are warranted. What is Known: • Viral load measurement in Respiratory Syncytial Virus (RSV) bronchiolitis depends on specimen collection, viral load quantification, and transport media. • The COVID-19 pandemic underscored the paramount significance of proper specimen collection, notably through nasal swabs. What is New: • RSV viral load was investigated in three-way-comparative analyses. • RSV viral load correlated well across PCR and tissue culture, nasal wash and swabs, and various transport media. RSV viral load did not correlate with clinical severity.

Participant perceptions and experiences of a novel community-based respiratory longitudinal sampling method in Liverpool, UK: A mixed methods feasibility study

Longitudinal, community-based sampling is important for understanding prevalence and transmission of respiratory pathogens. Using a minimally invasive sampling method, the FAMILY Micro study monitored the oral, nasal and hand microbiota of families for 6 months. Here, we explore participant experiences and opinions. A mixed methods approach was utilised. A quantitative questionnaire was completed after every sampling timepoint to report levels of discomfort and pain, as well as time taken to collect samples. Participants were also invited to discuss their experiences in a qualitative structured exit interview. We received questionnaires from 36 families. Most adults and children >5y experienced no pain (94% and 70%) and little discomfort (73% and 47% no discomfort) regardless of sample type, whereas children ≤5y experienced variable levels of pain and discomfort (48% no pain but 14% hurts even more, whole lot or worst; 38% no discomfort but 33% moderate, severe, or extreme discomfort). The time taken for saliva and hand sampling decreased over the study. We conducted interviews with 24 families. Families found the sampling method straightforward, and adults and children >5y preferred nasal sampling using a synthetic absorptive matrix over nasopharyngeal swabs. It remained challenging for families to fit sampling into their busy schedules. Adequate fridge/freezer space and regular sample pick-ups were found to be important factors for feasibility. Messaging apps proved extremely effective for engaging with participants. Our findings provide key information to inform the design of future studies, specifically that self-sampling at home using minimally invasive procedures is feasible in a family context.

Assessing the use of minimally invasive self-sampling at home for long-term monitoring of the microbiota within UK families

Monitoring the presence of commensal and pathogenic respiratory microorganisms is of critical global importance. However, community-based surveillance is difficult because nasopharyngeal swabs are uncomfortable and painful for a wide age range of participants. We designed a methodology for minimally invasive self-sampling at home and assessed its use for longitudinal monitoring of the oral, nasal and hand microbiota of adults and children within families. Healthy families with two adults and up to three children, living in and near Liverpool, United Kingdom, self-collected saliva, nasal lining fluid using synthetic absorptive matrices and hand swabs at home every two weeks for six months. Questionnaires were used to collect demographic and epidemiological data and assess feasibility and acceptability. Participants were invited to take part in an exit interview. Thirty-three families completed the study. Sampling using our approach was acceptable to 25/33 (76%) families, as sampling was fast (76%), easy (76%) and painless (60%). Saliva and hand sampling was acceptable to all participants of any age, whereas nasal sampling was accepted mostly by adults and children older than 5 years. Multi-niche self-sampling at home can be used by adults and children for longitudinal surveillance of respiratory microorganisms, providing key data for design of future studies.

Flow-Based CL-SMIA for the Quantification of Protein Biomarkers from Nasal Secretions in Comparison with Sandwich ELISA

Protein biomarkers in nasal secretions can be used as a measure to differentiate between allergies, airway diseases and infections for non-invasive diagnostics. The point-of-care quantification of biomarker levels using flow-based microarray facilitates precise and rapid diagnosis and displays the potential for targeted and effective treatment. For the first time, we developed a flow-based chemiluminescence sandwich microarray immunoassay (CL-SMIA) for the quantification of nasal interferon-beta (IFN-β) on the Microarray Chip Reader-Research (MCR-R). Polycarbonate foils are used as a cost-effective surface for immobilizing capture antibodies. By using a commercially available set of anti-human IFN-β antibodies, the CL-SMIA can be compared directly to an enzyme-linked immunosorbent assay (ELISA) performed in microtiter plates concerning the bioanalytical performance and economic issues. Pre-incubation of the sample with detection antibodies facilitates the lower consumption of detection antibodies, as this allows for a longer interaction time between the antibody and the biomarker. The direct injection of pre-incubated samples into the microarray chips eliminates the adsorption of proteins in the tubing as well as the contamination of the tubing and valves of the MCR-R with clinical samples. The small flow cell allows for a low sample volume of 50 μL. The limit of detection of 4.53 pg mL^-1 was slightly increased compared to a sandwich ELISA performed on microtiter plates which were 1.60 pg mL^-1. The possibility to perform the CL-SMIA in a multiplexed mode makes it a promising assay for the rapid and cost-effective non-invasive detection of biomarkers in nasal secretions.

Type III Interferons, Viral Loads, Age, and Disease Severity in Young Children With Respiratory Syncytial Virus Infection

BACKGROUND

The interplay among respiratory syncytial virus (RSV) loads, mucosal interferons (IFN), and disease severity in RSV-infected children is poorly understood.

METHODS

Children <2 years of age with mild (outpatients) or severe (inpatients) RSV infection and healthy controls were enrolled, and nasopharyngeal samples obtained for RSV loads and innate cytokines quantification. Patients were stratified by age (0-6 and >6-24 months) and multivariable analyses performed to identify predictors of disease severity.

RESULTS

In 2015-2019 we enrolled 219 RSV-infected children (78 outpatients; 141 inpatients) and 34 healthy controls. Type I, II, and III IFN concentrations were higher in children aged >6 versus 0-6 months and, like CXCL10, they were higher in outpatients than inpatients and correlated with RSV loads (P < .05). Higher IL6 concentrations increased the odds of hospitalization (odds ratio [OR], 2.30; 95% confidence interval [CI], 1.07-5.36) only in children >6 months, while higher IFN-λ2/3 concentrations had the opposite effect irrespective of age (OR, 0.38; 95% CI, .15-.86). Likewise, higher CXCL10 concentrations decreased the odds of hospitalization (OR, 0.21; 95% CI, .08-.48), oxygen administration (OR, 0.42; 95% CI, .21-.80),PICU admission (OR, 0.39; 95% CI, .20-.73), and prolonged hospitalization (OR, 0.57; 95% CI, .32-.98) irrespective of age.

CONCLUSIONS

Children with milder RSV infection and those aged >6 months had higher concentrations of mucosal IFNs, suggesting that maturation of mucosal IFN responses are associated with protection against severe RSV disease.

Multiplex Hybrid Antigen-Capture LC-MRM Quantification in Sera and Nasal Lining Fluid of AZD7442, a SARS-CoV-2-Targeting Antibody Combination

AZD7442 (tixagevimab [AZD8895]/cilgavimab [AZD1061]) is a monoclonal antibody (mAb) combination in development for the prevention and treatment of coronavirus disease 2019. Traditionally, bioanalysis of mAbs is performed using ligand binding assays (LBAs), which offer sensitivity, robustness, and ease of implementation. However, LBAs frequently require generation of critical reagents that typically take several months. Instead, we developed a highly sensitive (5 ng/mL limit of quantification) method using a hybrid LBA-liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) approach for quantification of the two codosed antibodies in serum and nasal lining fluid (NLF), a rare matrix. The method was optimized by careful selection of multiple reaction monitoring, capture reagents, magnetic beads, chromatographic conditions, evaluations of selectivity, and matrix effect. The final assay used viral spike protein receptor-binding domain as capture reagent and signature proteotypic peptides from the complementarity-determining region of each mAb for detection. In contrast to other methods of similar/superior sensitivity, our approach did not require multidimensional separations and can be operated in an analytical flow regime, ensuring high throughput and robustness required for clinical analysis at scale. The sensitivity of this method significantly exceeds typical sensitivity of ∼100 ng/mL for analytical flow 1D LBA-LC-MS/MS methods for large macromolecules, such as antibodies. Furthermore, infection and vaccination status did not impact method performance, ensuring method robustness and applicability to a broad patient population. This report demonstrated the general applicability of the hybrid LBA-LC-MS/MS approach to platform quantification of antibodies with high sensitivity and reproducibility, with specialized extension to matrices of increasing interest, such as NLF.

Mucosal Immune Responses to Respiratory Syncytial Virus

Despite over half a century of research, respiratory syncytial virus (RSV)-induced bronchiolitis remains a major cause of hospitalisation in infancy, while vaccines and specific therapies still await development. Our understanding of mucosal immune responses to RSV continues to evolve, but recent studies again highlight the role of Type-2 immune responses in RSV disease and hint at the possibility that it dampens Type-1 antiviral immunity. Other immunoregulatory pathways implicated in RSV disease highlight the importance of focussing on localised mucosal responses in the respiratory mucosa, as befits a virus that is essentially confined to the ciliated respiratory epithelium. In this review, we discuss studies of mucosal immune cell infiltration and production of inflammatory mediators in RSV bronchiolitis and relate these studies to observations from peripheral blood. We also discuss the advantages and limitations of studying the nasal mucosa in a disease that is most severe in the lower airway. A fresh focus on studies of RSV pathogenesis in the airway mucosa is set to revolutionise our understanding of this common and important infection.

Mediator production and severity of aspirin-induced respiratory reactions: Impact of sampling site and body mass index

BACKGROUND

Patients with aspirin-exacerbated respiratory disease can experience severe reactions during aspirin challenge that are associated with high levels of mast cell mediators. The tissue source and clinical factors contributing to systemic mediator levels are unknown.

OBJECTIVE

To determine the concordance between respiratory tract and systemic inflammatory mediator levels and identify clinical factors associated with these mediators.

METHODS

We performed an oral aspirin challenge in 30 subjects with aspirin-exacerbated respiratory disease. Respiratory symptoms and function, nasal mucosal fluid, blood, and urine were collected at baseline, at the onset of a respiratory reaction and over a 3-hour observation period. Changes in nasal and systemic mediator levels were compared.

RESULTS

Neither tryptase nor leukotriene E₄ levels in nasal fluid correlated with serum tryptase or urinary leukotriene E₄ at baseline or during reactions. We observed no association between the baseline or aspirin-induced change in nasal versus urinary leukotriene E₄ and serum tryptase levels. Body mass index inversely correlated with baseline and aspirin-induced urinary leukotriene E₄, prostaglandin D₂ metabolite, and serum tryptase levels, as well as with aspirin-induced symptoms and respiratory function, but not with nasal mediators.

CONCLUSION

The levels of nasal and systemic aspirin-induced mast cell products are discordant in aspirin-exacerbated respiratory disease. Systemically detected levels are likely derived from mast cells outside of the sinonasal cavity and do not accurately reflect upper respiratory tract production. Increased body mass index decreases systemic mast cell mediator production and reaction severity, supporting a contribution of metabolic regulation in aspirin-induced systemic reactions.

Neonatal airway immune profiles and asthma and allergy endpoints in childhood

BACKGROUND

The immune system plays a key role in the pathogenesis of asthma and allergy, but the role of the airway cytokine and chemokine composition in vivo in early life prior to symptom development has not been described previously. Here, we aimed to examine whether the neonatal airway immune composition associates with development of allergy and asthma in childhood.

METHODS

We measured unstimulated levels of 20 immune mediators related to the Type 1, Type 2, Type 17, or regulatory immune pathways in the airway mucosal lining fluid of 620 one-month-old healthy neonates from the COPSAC₂₀₁₀ birth cohort. Allergy and asthma were diagnosed at our research clinic by predefined algorithms and objective assessments at age 6 years. Principal component analyses were used to describe the airway cytokine and chemokine composition.

RESULTS

A neonatal airway immune profile particularly characterized by enhanced IL-1β and reduced CCL26 was significantly associated with later development of elevated specific IgE to inhaled allergens, a positive skin prick test, and allergic rhinitis, but not with food sensitization. Conversely, reduced Type 17 immune-associated markers, including IL-1β and CXCL8, showed trend of association with development of early asthma endpoints.

CONCLUSIONS

Development of early asthma endpoints and inhalant allergy during the first 6 years of life seems associated with distinctly perturbed airway immune profiles in neonatal life, which is suggestive of an early origin and different pathogenesis of childhood asthma and allergy. These exploratory findings suggest pre- and perinatal life as an important window of opportunity for prevention of asthma and inhalant allergy.

Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces viral shedding after SARS-CoV-2 D614G challenge in preclinical models

ChAdOx1 nCoV-19/AZD1222 is an approved adenovirus-based vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently being deployed globally. Previous studies in rhesus macaques revealed that intramuscular vaccination with ChAdOx1 nCoV-19/AZD1222 provided protection against pneumonia but did not reduce shedding of SARS-CoV-2 from the upper respiratory tract. Here, we investigated whether intranasally administered ChAdOx1 nCoV-19 reduces detection of virus in nasal swabs after challenging vaccinated macaques and hamsters with SARS-CoV-2 carrying a D614G mutation in the spike protein. Viral loads in swabs obtained from intranasally vaccinated hamsters were decreased compared to control hamsters, and no viral RNA or infectious virus was found in lung tissue after a direct challenge or after direct contact with infected hamsters. Intranasal vaccination of rhesus macaques resulted in reduced virus concentrations in nasal swabs and a reduction in viral loads in bronchoalveolar lavage and lower respiratory tract tissue. Intranasal vaccination with ChAdOx1 nCoV-19/AZD1222 reduced virus concentrations in nasal swabs in two different SARS-CoV-2 animal models, warranting further investigation as a potential vaccination route for COVID-19 vaccines.

Vaccine-Induced Cellular Immunity against Bordetella pertussis: Harnessing Lessons from Animal and Human Studies to Improve Design and Testing of Novel Pertussis Vaccines

Pertussis ('whooping cough') is a severe respiratory tract infection that primarily affects young children and unimmunised infants. Despite widespread vaccine coverage, it remains one of the least well-controlled vaccine-preventable diseases, with a recent resurgence even in highly vaccinated populations. Although the exact underlying reasons are still not clear, emerging evidence suggests that a key factor is the replacement of the whole-cell (wP) by the acellular pertussis (aP) vaccine, which is less reactogenic but may induce suboptimal and waning immunity. Differences between vaccines are hypothesised to be cell-mediated, with polarisation of Th1/Th2/Th17 responses determined by the composition of the pertussis vaccine given in infancy. Moreover, aP vaccines elicit strong antibody responses but fail to protect against nasal colonisation and/or transmission, in animal models, thereby potentially leading to inadequate herd immunity. Our review summarises current knowledge on vaccine-induced cellular immune responses, based on mucosal and systemic data collected within experimental animal and human vaccine studies. In addition, we describe key factors that may influence cell-mediated immunity and how antigen-specific responses are measured quantitatively and qualitatively, at both cellular and molecular levels. Finally, we discuss how we can harness this emerging knowledge and novel tools to inform the design and testing of the next generation of improved infant pertussis vaccines.

Mucosal immunity to severe acute respiratory syndrome coronavirus 2 infection

PURPOSE OF REVIEW

Despite its crucial role in protection against viral infections, mucosal immunity has been largely understudied in the context of coronavirus disease 2019 (COVID-19). This review outlines the current evidence about the role of mucosal immune responses in the clearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, as well as potential mucosal mechanisms of protection against (re-)infection.

RECENT FINDINGS

The angiotensin-converting enzyme 2 cellular entry receptor for SARS-CoV-2 is most highly expressed in the upper respiratory tract and most SARS-CoV-2 shedding occurs from the upper respiratory tract. Viral shedding peaks early during infection around the onset of symptoms, before dropping rapidly in most individuals within 7 days of symptom onset, suggesting mucosal inhibition of viral infection. Serum and mucosal immunoglobulin G and immunoglobulin M responses were found to be strongly correlated in infected patients, whereas correlations were much weaker for immunoglobulin A (IgA). Mucosal IgA responses have been detected in infected cases in the absence of serum antibody responses, with mucosal antibody levels correlating strongly with virus neutralization. Bulk and single-cell RNA sequencing analysis of nasopharyngeal swabs and bronchoalveolar lavage samples of COVID-19 patients revealed the induction of mucosal chemokine and cytokine genes, complement pathways, Janus Kinase/Signal Transducer and Activator of Transcription signaling and cytotoxic T cells.

SUMMARY

Although most clinical studies focus on antibodies and cellular immunity in peripheral blood, mucosal immune responses in the respiratory tract play a key role in the early restriction of viral replication and the clearance of SARS-CoV-2. Identification of mucosal biomarkers associated with viral clearance will allow monitoring of infection-induced immunity. Further studies are needed to understand how the systemic immunological endpoints measured in vaccination studies translate to mucosal protection against SARS-CoV-2 infection.

Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces shedding of SARS-CoV-2 D614G in rhesus macaques

Intramuscular vaccination with ChAdOx1 nCoV-19/AZD1222 protected rhesus macaques against pneumonia but did not reduce shedding of SARS-CoV-2. Here we investigate whether intranasally administered ChAdOx1 nCoV-19 reduces shedding, using a SARS-CoV-2 virus with the D614G mutation in the spike protein. Viral load in swabs obtained from intranasally vaccinated hamsters was significantly decreased compared to controls and no viral RNA or infectious virus was found in lung tissue, both in a direct challenge and a transmission model. Intranasal vaccination of rhesus macaques resulted in reduced shedding and a reduction in viral load in bronchoalveolar lavage and lower respiratory tract tissue. In conclusion, intranasal vaccination reduced shedding in two different SARS-CoV-2 animal models, justifying further investigation as a potential vaccination route for COVID-19 vaccines.

Increased nasal mucosal interferon and CCL13 response to a TLR7/8 agonist in asthma and allergic rhinitis

BACKGROUND

Acute respiratory viral infections are a major cause of respiratory morbidity and mortality, especially in patients with preexisting lung diseases such as asthma. Toll-like receptors are critical in the early detection of viruses and in activating innate immunity in the respiratory mucosa, but there is no reliable and convenient method by which respiratory mucosal innate immune responses can be measured.

OBJECTIVE

We sought to assess in vivo immune responses to an innate stimulus and compare responsiveness between healthy volunteers and volunteers with allergy.

METHODS

We administered the Toll-like receptor 7/8 agonist resiquimod (R848; a synthetic analogue of single-stranded RNA) or saline by nasal spray to healthy participants without allergy (n = 12), those with allergic rhinitis (n = 12), or those with allergic rhinitis with asthma (n = 11). Immune mediators in blood and nasal fluid and mucosal gene expression were monitored over time.

RESULTS

R848 was well tolerated and significantly induced IFN-α2a, IFN-γ, proinflammatory cytokines (TNF-α, IL-2, IL-12p70), and chemokines (CXCL10, C-C motif chemokine ligand [CCL]2, CCL3, CCL4, and CCL13) in nasal mucosal fluid, without causing systemic immune activation. Participants with allergic rhinitis or allergic rhinitis with asthma had increased IFN-α2a, CCL3, and CCL13 responses relative to healthy participants; those with asthma had increased induction of IFN-stimulated genes DExD/H-box helicase 58, MX dynamin-like GTPase 1, and IFN-induced protein with tetratricopeptide repeats 3.

CONCLUSIONS

Responses to nasal delivery of R848 enables simple assessment of mucosal innate responsiveness, revealing that patients with allergic disorders have an increased nasal mucosal IFN and chemokine response to the viral RNA analogue R848. This highlights that dysregulated innate immune responses of the nasal mucosa in allergic individuals may be important in determining the outcome of viral exposure.

Respiratory Syncytial Virus Infects Primary Neonatal and Adult Natural Killer Cells and Affects Their Antiviral Effector Function

Background

Respiratory syncytial virus (RSV) is a major cause of severe acute lower respiratory tract infections in infants. Natural killer (NK) cells are important antiviral effector cells that likely encounter RSV in the presence of virus-specific (maternal) antibodies. As NK cells potentially contribute to immunopathology, we investigated whether RSV affects their antiviral effector functions.

Methods

We assessed the phenotype and functionality of primary neonatal and adult NK cells by flow cytometry after stimulation with RSV or RSV-antibody complexes.

Results

We demonstrate for the first time that RSV infects neonatal and adult NK cells in vitro. Preincubation of virus with subneutralizing concentrations of RSV-specific antibodies significantly increased the percentage of infected NK cells. Upon infection, NK cells were significantly more prone to produce interferon-γ, while secretion of the cytotoxicity molecule perforin was not enhanced.

Conclusions

Our findings suggest that (antibody-enhanced) RSV infection of NK cells induces a proinflammatory rather than a cytotoxic response, which may contribute to immunopathology. Considering that most RSV vaccines currently being developed aim at inducing (maternal) antibodies, these results highlight the importance of understanding the interactions between innate effector cells and virus-specific antibodies.

A method of processing nasopharyngeal swabs to enable multiple testing

OBJECTIVE

To develop a method to perform multiple tests on a single nasopharyngeal (NP) swab.

METHODS

We collected a NP swab on children aged 2-12 years with acute sinusitis and processed it for bacterial culture, viruses, cytokine expression, and 16S ribosomal RNA gene sequencing analysis. During the course of the study, we expand the scope of evaluation to include RNA-sequencing, which we accomplished by cutting the tip of the swab.

RESULTS

Of the 174 children enrolled, 126 (72.4%) had a positive bacterial culture and 121 (69.5%) tested positive for a virus. Cytokine measurement, as judged by adequate levels of a housekeeping enzyme (glyceraldehyde 3-phosphate dehydrogenase), appeared successful. From the samples used for 16S ribosomal sequencing we recovered, on average, 16,000 sequences per sample, accounting for a total of 2646 operational taxonomic units across all samples sequenced. Samples used for RNA-sequencing had a mean RNA integrity number of 6.0. Cutting the tip of the swab did not affect the recovery yield for viruses or bacteria, nor did it affect species richness in microbiome analysis.

CONCLUSION

We describe a minimally invasive sample collection protocol that allows for multiple diagnostic and research investigations in young children.

Minimally Invasive Nasal Sampling in Children Offers Accurate Pneumococcal Colonization Detection

Nasopharyngeal colonization of potential respiratory pathogens such as Streptococcus pneumoniae is the major source of transmission and precursor of invasive disease. Swabbing deeply the nasopharynx, which is currently recommended by World Health Organization, provides accurate pneumococcal detection but is unpleasant. We showed that nasal lining fluid filter strips offer equal detection sensitivity.

Reduced Nasal Viral Load and IFN Responses in Infants with Respiratory Syncytial Virus Bronchiolitis and Respiratory Failure

RATIONALE

Respiratory syncytial virus (RSV) bronchiolitis is a major cause of morbidity and mortality in infancy. Severe disease is believed to result from uncontrolled viral replication, an excessive immune response, or both.

OBJECTIVES

To determine RSV load and immune mediator levels in nasal mucosal lining fluid by serial sampling of nasal fluids from cases of moderate and severe bronchiolitis over the course of infection.

METHODS

Infants with viral bronchiolitis necessitating admission (n = 55) were recruited from a pediatric center during 2016 and 2017. Of these, 30 were RSV infected (18 "moderate" and 12 mechanically ventilated "severe"). Nasal fluids were sampled frequently over time using nasosorption devices and nasopharyngeal aspiration. Hierarchical clustering of time-weighted averages was performed to investigate cytokine and chemokine levels, and gene expression profiling was conducted.

MEASUREMENTS AND MAIN RESULTS

Unexpectedly, cases with severe RSV bronchiolitis had lower nasal viral loads and reduced IFN-γ and C-C chemokine ligand 5/RANTES (regulated upon activation, normal T cell expressed and secreted) levels than those with moderate disease, especially when allowance was made for disease duration (all P < 0.05). Reduced cytokine/chemokine levels in severe disease were also seen in children with other viral infections. Gene expression analysis of nasopharyngeal aspiration samples (n = 43) confirmed reduced type-I IFN gene expression in severe bronchiolitis accompanied by enhanced expression of MUC5AC and IL17A.

CONCLUSIONS

Infants with severe RSV bronchiolitis have lower nasal viral load, CXCL10 (C-X-C motif chemokine ligand 10)/IP-10, and type-I IFN levels than moderately ill children, but enhanced MUC5AC (mucin-5AC) and IL17A gene expression in nasal cells.

Contribution of Cytokines to Tissue Damage During Human Respiratory Syncytial Virus Infection

The human respiratory syncytial virus (hRSV) remains one of the leading pathogens causing acute respiratory tract infections (ARTIs) in children younger than 2 years old, worldwide. Hospitalizations during the winter season due to hRSV-induced bronchiolitis and pneumonia increase every year. Despite this, there are no available vaccines to mitigate the health and economic burden caused by hRSV infection. The pathology caused by hRSV induces significant damage to the pulmonary epithelium, due to an excessive inflammatory response at the airways. Cytokines are considered essential players for the establishment and modulation of the immune and inflammatory responses, which can either be beneficial or harmful for the host. The deleterious effect observed upon hRSV infection is mainly due to tissue damage caused by immune cells recruited to the site of infection. This cellular recruitment takes place due to an altered profile of cytokines secreted by epithelial cells. As a result of inflammatory cell recruitment, the amounts of cytokines, such as IL-1, IL-6, IL-10, and CCL5 are further increased, while IL-10 and IFN-γ are decreased. However, additional studies are required to elicit the mediators directly associated with hRSV damage entirely. In addition to the detrimental induction of inflammatory mediators in the respiratory tract caused by hRSV, reports indicating alterations in the central nervous system (CNS) have been published. Indeed, elevated levels of IL-6, IL-8 (CXCL8), CCL2, and CCL4 have been reported in cerebrospinal fluid from patients with severe bronchiolitis and hRSV-associated encephalopathy. In this review article, we provide an in-depth analysis of the role of cytokines secreted upon hRSV infection and their potentially harmful contribution to tissue damage of the respiratory tract and the CNS.

Comparative Metabolomic Sampling of Upper and Lower Airways by Four Different Methods to Identify Biochemicals That May Support Bacterial Growth

Bacteria need nutrients from the host environment to survive, yet we know little about which biochemicals are present in the airways (the metabolome), which of these biochemicals are essential for bacterial growth and how they change with airway disease. The aims of this pilot study were to develop and compare methodologies for sampling the upper and lower airway metabolomes and to identify biochemicals present in the airways that could potentially support bacterial growth. Eight healthy human volunteers were sampled by four methods: two standard approaches - nasal lavage and induced sputum, and two using a novel platform, synthetic adsorptive matrix (SAM) strips—nasosorption and bronchosorption. Collected samples were analyzed by Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy (UPLC-MS/MS). Five hundred and eighty-one biochemicals were recovered from the airways belonging to a range of metabolomic super-pathways. We observed significant differences between the sampling approaches. Significantly more biochemicals were recovered when SAM strips were used, compared to standard sampling techniques. A range of biochemicals that could support bacterial growth were detected in the different samples. This work demonstrates for the first time that SAM strips are a highly effective method for sampling the airway metabolome. This work will assist further studies to understand how changes in the airway metabolome affect bacterial infection in patients with underlying airway disease.

Zooming in on the ERS fellowships and the International Congress

These fellowships are focused on young scientists and clinicians in the early stages of their research career in respiratory medicine. They provide a unique opportunity to visit a host institution in a country other than the candidate’s own for 1–3 months, with the aim of learning a research technique not available in the home institution. The call for applications will be open in the summer and will close on October 1, 2018.

An overview of @ERStalk fellowship opportunities with testimonials from previous fellows, and 12 tips for getting involved in #ERSCongress from @EarlyCareerERShttp://ow.ly/XUaI30jjpPc

Absorption of Nasal and Bronchial Fluids: Precision Sampling of the Human Respiratory Mucosa and Laboratory Processing of Samples

The methods of nasal absorption (NA) and bronchial absorption (BA) use synthetic absorptive matrices (SAM) to absorb the mucosal lining fluid (MLF) of the human respiratory tract. NA is a non-invasive technique which absorbs fluid from the inferior turbinate, and causes minimal discomfort. NA has yielded reproducible results with the ability to frequently repeat sampling of the upper airway.

By comparison, alternative methods of sampling the respiratory mucosa, such as nasopharyngeal aspiration (NPA) and conventional swabbing, are more invasive and may result in greater data variability. Other methods have limitations, for instance, biopsies and bronchial procedures are invasive, sputum contains many dead and dying cells and requires liquefaction, exhaled breath condensate (EBC) contains water and saliva, and lavage samples are dilute and variable.

BA can be performed through the working channel of a bronchoscope in clinic. Sampling is well tolerated and can be conducted at multiple sites in the airway. BA results in MLF samples being less dilute than bronchoalveolar lavage (BAL) samples.

This article demonstrates the techniques of NA and BA, as well as the laboratory processing of the resulting samples, which can be tailored to the desired downstream biomarker being measured. These absorption techniques are useful alternatives to the conventional sampling techniques used in clinical respiratory research.

Prevention and treatment of respiratory viral infections: Presentations on antivirals, traditional therapies and host-directed interventions at the 5th ISIRV Antiviral Group conference

The International Society for Influenza and other Respiratory Virus Diseases held its 5th Antiviral Group (isirv-AVG) Conference in Shanghai, China, in conjunction with the Shanghai Public Health Center and Fudan University from 14-16 June 2017. The three-day programme encompassed presentations on some of the clinical features, management, immune responses and virology of respiratory infections, including influenza A(H1N1)pdm09 and A(H7N9) viruses, MERS-CoV, SARS-CoV, adenovirus Type 80, enterovirus D68, metapneumovirus and respiratory syncytial virus (RSV). Updates were presented on several therapeutics currently in clinical trials, including influenza polymerase inhibitors pimodivir/JNJ6362387, S033188, favipiravir, monoclonal antibodies MHAA45449A and VIS410, and host directed strategies for influenza including nitazoxanide, and polymerase ALS-008112 and fusion inhibitors AK0529, GS-5806 for RSV. Updates were also given on the use of the currently licensed neuraminidase inhibitors. Given the location in China, there were also presentations on the use of Traditional Chinese Medicines. Following on from the previous conference, there were ongoing discussions on appropriate endpoints for severe influenza in clinical trials from regulators and clinicians, an issue which remains unresolved. The aim of this conference summary is to provide information for not only conference participants, but a detailed referenced review of the current status of clinical trials, and pre-clinical development of therapeutics and vaccines for influenza and other respiratory diseases for a broader audience.