Pathogenesis of Viral Infection in Exacerbations of Airway Disease

Inducible gene expression of IκB-kinase ε is dependent on nuclear factor-κB in human pulmonary epithelial cells

While IκB-kinase-ε (IKKε) induces immunomodulatory genes following viral stimuli, its up-regulation by inflammatory cytokines remains under-explored. Since airway epithelial cells respond to airborne insults and potentiate inflammation, IKKε expression was characterized in pulmonary epithelial cell lines (A549, BEAS-2B) and primary human bronchial epithelial cells grown as submersion or differentiated air-liquid interface cultures. IKKε expression was up-regulated by the pro-inflammatory cytokines, interleukin-1β (IL-1β) and tumour necrosis factor-α (TNFα). Thus, mechanistic interrogations in A549 cells were used to demonstrate the NF-κB dependence of cytokine-induced IKKε. Furthermore, chromatin immunoprecipitation in A549 and BEAS-2B cells revealed robust recruitment of the NF-κB subunit, p65, to one 5' and two intronic regions within the IKKε locus (IKBKE). In addition, IL-1β and TNFα induced strong RNA polymerase 2 recruitment to the 5' region, the first intron, and the transcription start site. Stable transfection of the p65-binding regions into A549 cells revealed IL-1β- and TNFα-inducible reporter activity that required NF-κB, but was not repressed by glucocorticoid. While critical NF-κB motifs were identified in the 5' and downstream intronic regions, the first intronic region did not contain functional NF-κB motifs. Thus, IL-1β- and TNFα-induced IKKε expression involves three NF-κB-binding regions, containing multiple functional NF-κB motifs, and potentially other mechanisms of p65 binding through non-classical NF-κB binding motifs. By enhancing IKKε expression, IL-1β may prime, or potentiate, responses to alternative stimuli, as modelled by IKKε phosphorylation induced by phorbol 12-myristate 13-acetate. However, since IKKε expression was only partially repressed by glucocorticoid, IKKε-dependent responses could contribute to glucocorticoid-resistant disease.

Mutations at the conserved N-Terminal of the human Rhinovirus capsid gene VP4, and their impact on the immune response

Rhinoviruses (RV) are the major cause of chronic obstructive pulmonary disease and are associated with exacerbation development as well as community-acquired pneumonia in children, leading to substantial morbidity, mortality, and hospital admission. Here we have examined how changes at the amino terminal of the conserved VP4 epitope of different RV serotypes may affect pulmonary cytokine and chemokine responses and disease severity. Samples positive for rhinovirus were used for genetic characterization, followed by profiling gene expression of pulmonary Th1 and Th2 cytokines/chemokines by RT-PCR arrays. Genetic sequencing and homology 3D modeling revealed changes at the amino terminal of the conserved viral protein 4 (VP4) epitope in the RV-A101 serotype, especially serine at several positions that are important for interactive binding with the host immune cells. We found dysregulation of pulmonary gene expression of Th1- and Th2-related cytokines and chemokines in RV-A 101 and RV-C 8 pneumonia patients. These findings might contribute to a better understanding of RV immunity and the potential mechanisms underlying the pathogenesis of severe RV infections, but further functional studies are needed to confirm the causal relationship.

The acute care burden of asthma in children was profoundly reduced during the COVID-19 pandemic: A multi-centre Canadian retrospective study

Objectives

Asthma is a chronic lung condition that can be exacerbated when triggered by viruses. Pandemic public health restrictions aimed to reduce COVID-19 transmission indirectly effected other circulating viruses. This study assessed the impact of the pandemic and associated public health measures on acute paediatric asthma across four tertiary sites in three Canadian provinces. We queried whether pandemic-related changes would impair preventive care and delay presentation to care, increasing asthma exacerbation severity.

Methods

This retrospective study compared the frequency of acute care access and severity of presentation to emergency departments (ED) for acute asthma to four tertiary care children's hospitals during the COVID-19 pandemic (from March 17, 2020 to June 30, 2021) to a pre-lockdown control period (July 1, 2018 to March 16, 2020). Data was subjected to interrupted time series and Chi-square analysis.

Results

Our study included 26,316 acute asthma visits to ED. Sites experienced a 63% to 89% reduction in acute asthma visits during the pandemic, compared with pre-lockdown controls, and a 17% to 85% reduction in asthma, that is out of proportion as a fraction of all-cause ED visits. For asthma, there was no difference in severity measured by rate of ward admission or rate of Paediatric Intensive Care Unit (PICU) admission.

Conclusions

Public health measures appear to have resulted in a specific protective association on acute asthma with reduced acute care utilization over and above the reduction in all-cause presentations, without an increase in severity upon presentation. Our study indicates an importance to antiviral public health and engineering strategies to reduce viral transmission and thereby asthma morbidity.

Single-Molecule Analysis of Genome Uncoating from Individual Human Rhinovirus Particles, and Modulation by Antiviral Drugs

Infection of humans by many viruses is typically initiated by the internalization of a single virion in each of a few susceptible cells. Thus, the outcome of the infection process may depend on stochastic single-molecule events. A crucial process for viral infection, and thus a target for developing antiviral drugs, is the uncoating of the viral genome. Here a force spectroscopy procedure using an atomic force microscope is implemented to study uncoating for individual human rhinovirus particles. Application of an increasing mechanical force on a virion led to a high force-induced structural transition that facilitated extrusion of the viral RNA molecule without loss of capsid integrity. Application of force to virions that h ad previously extruded the RNA, or to RNA-free capsids, led to a lower force-induced event associated with capsid disruption. The kinetic parameters are determined for each reaction. The high-force event is a stochastic process governed by a moderate free energy barrier (≈20 kcal mol-1 ), which results in a heterogeneous population of structurally weakened virions in which different fractions of the RNA molecule are externalized. The effects of antiviral compounds or capsid mutation on the kinetics of this reaction reveal a correlation between the reaction rate and virus infectivity.

RVdb: a comprehensive resource and analysis platform for rhinovirus research

Rhinovirus (RV), a prominent causative agent of both upper and lower respiratory diseases, ranks among the most prevalent human respiratory viruses. RV infections are associated with various illnesses, including colds, asthma exacerbations, croup and pneumonia, imposing significant and extended societal burdens. Characterized by a high mutation rate and genomic diversity, RV displays a diverse serological landscape, encompassing a total of 174 serotypes identified to date. Understanding RV genetic diversity is crucial for epidemiological surveillance and investigation of respiratory diseases. This study introduces a comprehensive and high-quality RV data resource, designated RVdb (http://rvdb.mgc.ac.cn), covering 26 909 currently identified RV strains, along with RV-related sequences, 3D protein structures and publications. Furthermore, this resource features a suite of web-based utilities optimized for easy browsing and searching, as well as automatic sequence annotation, multiple sequence alignment (MSA), phylogenetic tree construction, RVdb BLAST and a serotyping pipeline. Equipped with a user-friendly interface and integrated online bioinformatics tools, RVdb provides a convenient and powerful platform on which to analyse the genetic characteristics of RVs. Additionally, RVdb also supports the efforts of virologists and epidemiologists to monitor and trace both existing and emerging RV-related infectious conditions in a public health context.

Genetic diversity and characterization of rhinoviruses from Chinese clinical samples with a global perspective

IMPORTANCE

Based on clinical samples collected in China, we detected and reported 22 types for the first time in China, as well as three types for the first time in Asia, and reported their genetic characteristics and diversity. We identified a novel type of Rhinovirus (RV), A110, highlighting its unique genetic features. We annotated the genomic structure and serotype of all the existing RV sequences in the database, and four novel RV types were identified and their genetic diversity reported. Combined with the sequence annotation, we constructed a complete VP1 data set of RV and conducted the first large-scale evolutionary dynamics analysis of RV. Based on a high-quality data set, we conducted a comprehensive analysis of the guanine-cytosine (GC) content variations among serotypes of RVs. This study provides crucial theoretical support and valuable data for understanding RV's genetic diversity and developing antiviral strategies.

Vaccine-elicited B- and T-cell immunity to SARS-CoV-2 is impaired in chronic lung disease patients

Background

While vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) provides significant protection from coronavirus disease 2019, the protection afforded to individuals with chronic lung disease is less well established. This study seeks to understand how chronic lung disease impacts SARS-CoV-2 vaccine-elicited immunity.

Methods

Deep immune phenotyping of humoral and cell-mediated responses to the SARS-CoV-2 vaccine was performed in patients with asthma, COPD and interstitial lung disease (ILD) compared to healthy controls.

Results

48% of vaccinated patients with chronic lung diseases had reduced antibody titres to the SARS-CoV-2 vaccine antigen relative to healthy controls. Vaccine antibody titres were significantly reduced among asthma (p<0.035), COPD (p<0.022) and a subset of ILD patients as early as 3-4 months after vaccination, correlating with decreased vaccine-specific memory B-cells in circulation. Vaccine-specific memory T-cells were significantly reduced in patients with asthma (CD8+ p<0.004; CD4+ p<0.023) and COPD (CD8+ p<0.008) compared to healthy controls. Impaired T-cell responsiveness was also observed in a subset of ILD patients (CD8+ 21.4%; CD4+ 42.9%). Additional heterogeneity between healthy and disease cohorts was observed among bulk and vaccine-specific follicular T-helper cells.

Conclusions

Deep immune phenotyping of the SARS-CoV-2 vaccine response revealed the complex nature of vaccine-elicited immunity and highlights the need for more personalised vaccination schemes in patients with underlying lung conditions.

Asthma Exacerbations: Patient Features and Potential Long-Term Implications

Asthma exacerbations occur in the context of a complex interplay between external exposures and host factors. Respiratory tract viral infections, in particular rhinovirus, are dominant initiators of exacerbations, with allergens and other inhalation exposures as additional key contributors. The presence of underlying type II inflammation, with associated biomarker elevations, is a major driver of exacerbation risk and mechanism, as evidenced by the consistent reduction of exacerbations seen with biologics targeting these pathways. Several genetic polymorphisms are associated with exacerbations, and while they may individually have small effects, they are cumulatively important and magnified by environmental exposures. A history of exacerbations predicts future exacerbations with potentially negative implications on long-term lung health.

Gut-Lung Microbiota Interaction in COPD Patients: A Literature Review

Respiratory diseases are one of the leading causes of death in the world, which is why a lot of attention has been recently paid to studying the possible mechanisms for the development of pulmonary diseases and assessing the impact on their course. The microbiota plays an important role in these processes and influences the functionality of the human immune system. Thus, alterations in the normal microflora contribute to a reduction in immunity and a more severe course of diseases. In this review, we summarized the information about gut and lung microbiota interactions with particular attention to their influence on the course of chronic obstructive pulmonary disease (COPD).

Viral Infection and Airway Epithelial Immunity in Asthma

Viral respiratory tract infections are associated with asthma development and exacerbation in children and adults. In the course of immune responses to viruses, airway epithelial cells are the initial platform of innate immunity against viral invasion. Patients with severe asthma are more vulnerable than those with mild to moderate asthma to viral infections. Furthermore, in most cases, asthmatic patients tend to produce lower levels of antiviral cytokines than healthy subjects, such as interferons produced from immune effector cells and airway epithelial cells. The epithelial inflammasome appears to contribute to asthma exacerbation through overactivation, leading to self-damage, despite its naturally protective role against infectious pathogens. Given the mixed and complex immune responses in viral-infection-induced asthma exacerbation, this review examines the diverse roles of airway epithelial immunity and related potential therapeutic targets and discusses the mechanisms underlying the heterogeneous manifestations of asthma exacerbations.

Emergency hospitalization caused by non-COVID-19 respiratory diseases before and during the COVID-19 pandemic: A retrospective observational cohort study

Background

The coronavirus disease 2019 (COVID-19) pandemic as well as the subsequent prevention and control measures is like a quasi-experiment intervention that might have changed the features of emergency hospitalizations. Mortality is high in patient hospitalization due to emergency respiratory diseases (ERD). Therefore, we compared the characteristics of these patients before and during the pandemic. Exploring this issue might contribute to decision-making of emergency management when most of the resources and attention has been devoted to combat COVID-19.

Methods

This study was a retrospective observational cohort study. All emergency hospitalizations due to ERD from January 1, 2019 to December 31, 2020 in a tertiary hospital in China were included. Data including patients’ age, sex, and clinical outcomes were extracted. Air quality was collected from the official online platform. Clinical characteristics were compared and odds ratios were calculated.

Results

The ERD hospitalization rate was lower in 2020 than in 2019 (6.4 vs. 4.3%, χ² = 55.449, P = 0.000) with a 50.65% reduction; however, the patients were older in 2020 than in 2019 (P = 0.000) with a higher proportion of admission to the intensive care unit (ICU) (46 vs. 33.5%, χ² = 20.423, P = 0.000) and a longer ICU stay (P = 0.000). The overall intubation rate, hospital mortality, and rate of discharge due to ineffective treatment in 2020 were higher than those in 2019 (15.6 vs. 8%, χ² = 18.578, P = 0.000; 4.2 vs. 1.1%, χ² = 4.122, P = 0.000; 5.5 vs. 2.4%, χ² = 8.93, P = 0.000, respectively). The logistic regression analysis indicated hospitalizations due to ERD were mainly associated with PM2.5 and sulfur dioxide on the day, and on the 4th and 5th days before admission (P = 0.034 and 0.020, 0.021 and 0.000, 0.028, and 0.027, respectively) in 2019. However, in 2020, the relationship between parameters of air quality and hospitalization changed.

Conclusion

The COVID-19 pandemic has changed the characteristics of emergency hospitalization due to ERD with a larger proportion of severe patients and poorer prognosis. The effect of air quality on emergencies were weakened. During the COVID-19 pandemic, it is necessary to pay more attention to the non-COVID-19 emergency patients.

Incorporating Target-Specific Pharmacophoric Information into Deep Generative Models for Fragment Elaboration

Despite recent interest in deep generative models for scaffold elaboration, their applicability to fragment-to-lead campaigns has so far been limited. This is primarily due to their inability to account for local protein structure or a user's design hypothesis. We propose a novel method for fragment elaboration, STRIFE, that overcomes these issues. STRIFE takes as input fragment hotspot maps (FHMs) extracted from a protein target and processes them to provide meaningful and interpretable structural information to its generative model, which in turn is able to rapidly generate elaborations with complementary pharmacophores to the protein. In a large-scale evaluation, STRIFE outperforms existing, structure-unaware, fragment elaboration methods in proposing highly ligand-efficient elaborations. In addition to automatically extracting pharmacophoric information from a protein target's FHM, STRIFE optionally allows the user to specify their own design hypotheses.

How the coronavirus disease 2019 pandemic changed the patterns of healthcare utilization by geriatric patients and the crowding: a call to action for effective solutions to the access block

The geriatric population constitutes a large slice of the population of Western countries and a class of fragile patients, with greater deaths due to COVID-19. The patterns of healthcare utilization change during pandemic disease outbreaks. Identifying the patterns of changes of this particular fragile subpopulation is important for future preparedness and response. Overcrowding in the emergency department (ED) can occur because of the volume of patients waiting to be seen, delays in patient assessment or treatment in the ED, or impediments to leaving the ED once the treatment has been completed. Overcrowding has become a serious and growing issue globally, which represents a serious impediment to healthcare utilization. To estimate the rate of ED visits attributable to the outbreak and guide the planning of strategies for managing ED access or after the outbreak of transmittable respiratory diseases. This observational study was based on a retrospective review of the epidemiological and clinical records of patients aged > 75 years who visited the Foundation IRCCS Policlinic San Matteo during the first wave of COVID-19 outbreak (February 21 to May 1, 2020; pandemic group). The analysis methods included estimation of the changes in the epidemiological and clinical data from the annual baseline data after the start of the COVID-19 pandemic. Outcome measures and analysis: Primary objective is the evaluation of ED admission rate change and ED overcrowding. Secondary objectives are the evaluation of modes of ED access by reason and triage code, access types, clinical outcomes (such as admission and mortality rates). During the pandemic, ED crowding increased dramatically, although the overall number of patients decreased, in the face of a percentage increase in those with high-acuity conditions, because of changes in patient management that have prolonged length of stay (LOS) and increased rates of access block. Overcrowding during the COVID-19 pandemic can be attributed to the Access Block. Access Block solutions are hence required to prevent a recurrence of crowding to any new viral wave or new epidemic in the future.

Serum Amyloid A1: A Biomarker for Neutrophilic Airway Inflammation in Adult Asthmatic Patients

Purpose

We evaluated the role of serum amyloid A1 (SAA1) in the pathogenesis of airway inflammation according to the phenotype of asthma.

Methods

One hundred twenty-two asthmatic patients and 60 healthy control subjects (HCs) were enrolled to measure SAA1 levels. The production of SAA1 from airway epithelial cells (AECs) and its effects on macrophages and neutrophils were investigated in vitro and in vivo.

Results

The SAA1 levels were significantly higher in sera of asthmatic patients than in those of HCs (P = 0.014); among asthmatics, patients with neutrophilic asthma (NA) showed significantly higher SAA1 levels than those with non-NA (P < 0.001). In vitro, polyinosinic:polycytidylic acid (Poly I-C) treatment markedly enhanced the production of SAA1 from AECs, which was further augmented by neutrophils; SAA1 could induce the production of interleukin (IL)-6, IL-8, and S100 calcium-binding protein A9 from AECs. Additionally, SAA1 activated neutrophils and macrophages isolated from peripheral blood of asthmatics, releasing neutrophil extracellular traps (NETs) and secreting proinflammatory cytokines presenting M1 phenotype, respectively. In ovalbumin-induced asthma mice, Poly I-C treatment significantly increased SAA1 levels as well as IL-17A/interferon-gamma/IL-33 levels in bronchoalveolar lavage fluid (BALF), leading to airway hyperresponsiveness and inflammation. The highest levels of SAA1 and neutrophilia were noted in the BALF and sera of the NA mouse model, followed by the mixed granulocytic asthma (MA) model. Especially, SAA1 induced IL-17/retinoic acid receptor-related orphan receptor γt expression from activated CD4+ T lymphocytes in asthmatic mice.

Conclusions

The results show that SAA1 could induce neutrophilic airway inflammation by activating neutrophils along with NET formation, M1 macrophages, and Th2/Th17 predominant cells, contributing to the phenotype of NA or MA.

Experimental rhinovirus infection induces an antiviral response in circulating B cells which is dysregulated in patients with asthma

BACKGROUND

Rhinoviruses are the predominant cause of respiratory viral infections and are strongly associated with asthma exacerbations. While humoral immunity plays an important role during virus infections, cellular aspects of this response are less well understood. Here, we investigated the antiviral response of circulating B cells upon experimental rhinovirus infection in healthy individuals and asthma patients.

METHODS

We purified B cells from experimentally infected healthy individuals and patients with asthma and subjected them to total RNA-sequencing. Rhinovirus-derived RNA was measured in isolated B cells using a highly sensitive PCR. B cells were stimulated with rhinovirus in vitro to further study gene expression, expression of antiviral proteins and B-cell differentiation in response rhinovirus stimulation. Protein expression of pro-inflammatory cytokines in response to rhinovirus was assessed using a proximity extension assay.

RESULTS

B cells isolated from experimentally infected subjects exhibited an antiviral gene profile linked to IFN-alpha, carried viral RNA in vivo and were transiently infected by rhinovirus in vitro. B cells rapidly differentiated into plasmablasts upon rhinovirus stimulation. While B cells lacked expression of interferons in response to rhinovirus exposure, co-stimulation with rhinovirus and IFN-alpha upregulated pro-inflammatory cytokine expression suggesting a potential new function of B cells during virus infections. Asthma patients showed extensive upregulation and dysregulation of antiviral gene expression.

CONCLUSION

These findings add to the understanding of systemic effects of rhinovirus infections on B-cell responses in the periphery, show potential dysregulation in patients with asthma and might also have implications during infection with other respiratory viruses.

Immune responses and exacerbations in severe asthma

Asthma as a clinical entity manifests with a broad spectrum of disease severity. Unlike milder asthma, severe disease is poorly controlled by inhaled corticosteroids, the current standard of care. Transcriptomic data, along with patient characteristics and response to biologics show that though Type 2 (T2) immune response remains an integral feature of asthma, additional molecular and immunologic factors may play important roles in pathogenesis. Mechanisms of T2 development, cellular sources of T2 cytokines and their relationship to additional immune pathways concurrently activated may distinguish several different subphenotypes, and perhaps endotypes of asthma, with differential response to non-specific and targeted anti-inflammatory therapies. Recent data have also associated non-T2 cytokines derived from T cells, particularly IFN-γ, and epithelial mediators with severe asthma. These topics and their relationships to acute asthma exacerbations are discussed in this review.

Association of asthma comorbidity with poor prognosis of coronavirus disease 2019

Background

While global health agencies have listed asthma as a vulnerability for severe cases of coronavirus disease 2019 (COVID-19), the evidence supporting this is scarce.

Methods

A nationwide cohort study was conducted using the validated Korean national health insurance claim data of patients diagnosed with COVID-19 between January 1 and April 8, 2020. Asthma comorbidity was determined using a diagnosis code assigned by the physician and the prescription of asthma-related medications. The clinical course of COVID-19 was classified into 3 severity grades according to the requirements for oxygen supply and mechanical ventilation. We also evaluated the association of asthma with overall and in-hospital mortality of COVID-19.

Results

Asthma morbidity was a significant risk factor for severe COVID-19 (grade 2 requiring oxygen supply) (adjusted odds ratio [aOR] = 1.341, 95% confidence interval [CI], 1.051−1.711, P = 0.018) and grade 3 requiring mechanical ventilation or leading to death (aOR = 1.723, 95% CI: 1.230−2.412, P = 0.002) multinomial logistic regression adjusting co-risk factors. Asthma was also significantly associated with mortality of COVID-19 (aOR = 1.453, 95% CI: 1.015−2.080, P = 0.041) and was revealed to have a shorter time to in-hospital mortality of COVID-19 (P < 0.001). Patients with recent asthma exacerbation showed more severe COVID-19 of grade 3 (OR = 7.371, 95% CI: 2.018−26.924, P = 0.003) and higher mortality (OR = 9.208, 95% CI: 2.597−32.646, P < 0.001) in univariable analysis, but the statistical significance was not found in multivariable analysis.

Conclusion

Asthma morbidity was associated with severity and mortality of COVID-19. Patients with asthma should pay more attention to avoid worsening of COVID-19.

Effect of influenza vaccination in patients with asthma

BACKGROUND:

Although annual influenza vaccination is recommended for persons with asthma, its effectiveness in this patient population is not well described. We evaluated the effect of influenza vaccination in the current and previous seasons in preventing influenza among people with asthma.

METHODS:

Using population health data from the Navarre region of Spain for the 2015/16 to 2019/20 influenza seasons, we conducted a test-negative case–control study to assess the effect of influenza vaccination in the current and 5 previous seasons. From patients presenting to hospitals and primary health care centres with influenza-like illness who underwent testing for influenza, we estimated the effects of influenza vaccination among patients with asthma overall and between those presenting as inpatients or outpatients, as well as between patients with and without asthma.

RESULTS:

Of 1032 patients who had asthma and were tested, we confirmed that 421 had influenza and the remaining 611 were test-negative controls. We found that the average effect of influenza vaccination was 43% (adjusted odds ratio [OR] 0.57, 95% confidence interval [CI] 0.40 to 0.80) for current-season vaccination regardless of previous doses, and 38% (adjusted OR 0.62, 95% CI 0.39 to 0.96) for vaccination in previous seasons only. Effects were similar for outpatients and inpatients. Among patients with asthma and confirmed influenza, current-season vaccination did not reduce the odds of hospital admission (adjusted OR 1.05, 95% CI 0.51 to 2.18). Influenza vaccination effects were similar for patients with and without asthma.

INTERPRETATION:

We estimated that, on average, current or previous influenza vaccination of people with asthma prevented almost half of influenza cases. These results support recommendations that people with asthma receive influenza vaccination.

Aging and respiratory viral infection: from acute morbidity to chronic sequelae

The altered immune response in aged hosts play a vital role in contributing to their increased morbidity and mortality during respiratory virus infections. The aged hosts display impaired antiviral immune response as well as increased risk for long-term pulmonary sequelae post virus clearance. However, the underlying cellular and molecular mechanisms driving these alterations of the immune compartment have not been fully elucidated. During the era of COVID-19 pandemic, a better understanding of such aspects is urgently needed to provide insight that will benefit the geriatric patient care in prevention as well as treatment. Here, we review the current knowledge about the unique immune characteristics of aged hosts during homeostasis and respiratory virus infections.

Influence of age, sex and respiratory viruses on the rates of emergency department visits and hospitalisations with respiratory tract infections, asthma and COPD

Background

The importance of age, sex and respiratory virus prevalence in emergency department (ED) visits and hospitalisations for respiratory tract infections (RTIs), asthma and COPD in a whole population over time is not well established.

Methods

This study retrospectively analysed data for daily ED visits and hospitalisations from 2003 to 2013 in Ontario, Canada and the daily number of virus positive tests. Daily numbers of ED visits and hospitalisations with RTIs, asthma and COPD listed as a primary diagnosis were collected from the Canadian Institute for Health Information. Virus data were obtained from the Respiratory Virus Detection Surveillance System. Multiple linear regression was used to assess the association of individual viruses with the daily rates.

Results

There were 4 365 578 ED visits and 321 719 (7.4%) admissions for RTIs, 817 141 ED visits and 260 665 (31.9%) admissions for COPD and 649 666 ED visits and 68 626 (10.6%) admissions for asthma. Respiratory syncytial virus and influenza A were associated with male ED visits, whereas human rhinovirus was associated with female ED visits for RTIs in preschool children. 19.2% of males, but only 7.2% of females were admitted. The correlation between the prevalence of each virus and ED visits and hospitalisations for asthma was weak, irrespective of age group and sex. Influenza A was most strongly associated with COPD ED visits and hospitalisations in males and females.

Conclusions

There are significant age and sex differences in the contribution of respiratory viruses to the number of ED visits and hospitalisations for RTIs, asthma and COPD.

There are important age- and sex-related differences in the contribution of respiratory viruses to the number of ED visits and hospitalisations for respiratory tract infections, asthma and COPDhttps://bit.ly/39hrhIW

Mechanisms of Rhinovirus Neutralisation by Antibodies

Antibodies are a critical immune correlate of protection for rhinoviruses, particularly those antibodies found in the secretory compartment. For nonenveloped viruses such as rhinoviruses, antibody binding to regions of the icosahedral capsid can neutralise infections by a number of different mechanisms. The purpose of this review is to address the neutralising mechanisms of antibodies to rhinoviruses that would help progress vaccine development. At least five mechanisms of antibody neutralisation have been identified which depend to some extent on the antibody binding footprints upon the capsid. The most studied mechanisms are virion aggregation, inhibition of attachment to cells, and stabilisation or destabilisation of the capsid structure. Newer mechanisms of degradation inside the cell through cytoplasmic antibody detection or outside by phagocytosis rely on what might have been previously considered as non-neutralising antibodies. We discuss these various approaches of antibody interference of rhinoviruses and offer suggestions as to how these could influence vaccine design.

Effect of Monthly Vitamin D Supplementation on Preventing Exacerbations of Asthma or Chronic Obstructive Pulmonary Disease in Older Adults: Post Hoc Analysis of a Randomized Controlled Trial

Randomized controlled trials have suggested that vitamin D supplementation can prevent asthma and chronic obstructive pulmonary disease (COPD) exacerbations. For COPD, the benefit appears to be limited to individuals with baseline 25-hydroxyvitamin D (25OHD) levels <25 nmol/L. We performed a post hoc analysis of data from a randomized, double-blinded, placebo-controlled trial to investigate the effect that monthly, high-dose vitamin D supplementation (versus placebo) had on older adults with asthma and/or COPD. Specifically, we investigated whether vitamin D supplementation prevented exacerbations of these conditions. Participants were randomly assigned either to an initial oral dose of 200,000 IU vitamin D3 followed by 100,000 IU monthly or to placebo, with an average follow-up period of 3.3 years. Among the 5110 participants, 775 had asthma or COPD at the beginning of the study, and were eligible for inclusion in this analysis. Exacerbations were defined by the prescription of a short-burst of oral corticosteroids. The mean age of the participants was 67 years old, and 56% were male. The mean baseline blood 25OHD level was 63 nmol/L; 2.3% were <25 nmol/L. Overall, we found that vitamin D supplementation did not affect the exacerbation risk (hazard ratio 1.08; 95%CI 0.84–1.39). Among those with baseline 25OHD <25 nmol/L, however, the hazard ratio was 0.11 (95%CI 0.02–0.51); p for interaction = 0.001. Although monthly vitamin D supplementation had no overall impact on risk of exacerbations of asthma or COPD, we found evidence of a probable benefit among those with severe vitamin D deficiency.

ABCF1 Regulates dsDNA-induced Immune Responses in Human Airway Epithelial Cells

Background: The airway epithelium represents a critical component of the human lung that helps orchestrate defenses against respiratory tract viral infections, which are responsible for more than 2.5 million deaths/year globally. Innate immune activities of the airway epithelium rely on Toll-like receptors (TLRs), nucleotide binding and leucine-rich-repeat pyrin domain containing (NLRP) receptors, and cytosolic nucleic acid sensors. ATP Binding Cassette (ABC) transporters are ubiquitous across all three domains of life—Archaea, Bacteria, and Eukarya—and expressed in the human airway epithelium. ABCF1, a unique ABC family member that lacks a transmembrane domain, has been defined as a cytosolic nucleic acid sensor that regulates CXCL10, interferon-β expression, and downstream type I interferon responses. We tested the hypothesis that ABCF1 functions as a dsDNA nucleic acid sensor in human airway epithelial cells important in regulating antiviral responses.

Methods: Expression and localization experiments were performed using in situ hybridization and immunohistochemistry in human lung tissue, while confirmatory transcript and protein expression was performed in human airway epithelial cells. Functional experiments were performed with siRNA methods in a human airway epithelial cell line. Complementary transcriptomic analyses were performed to explore the contributions of ABCF1 to gene expression patterns.

Results: Using archived human lung and human airway epithelial cells, we confirm expression of ABCF1 gene and protein expression in these tissue samples, with a role for mediating CXCL10 production in response to dsDNA viral mimic challenge. Although, ABCF1 knockdown was associated with an attenuation of select genes involved in the antiviral responses, Gene Ontology analyses revealed a greater interaction of ABCF1 with TLR signaling suggesting a multifactorial role for ABCF1 in innate immunity in human airway epithelial cells.

Conclusion: ABCF1 is a candidate cytosolic nucleic acid sensor and modulator of TLR signaling that is expressed at gene and protein levels in human airway epithelial cells. The precise level where ABCF1 protein functions to modulate immune responses to pathogens remains to be determined but is anticipated to involve IRF-3 and CXCL10 production.

Insights Into Type I and III Interferons in Asthma and Exacerbations

Asthma is a highly prevalent, chronic respiratory disease that impacts millions of people worldwide and causes thousands of deaths every year. Asthmatics display different phenotypes with distinct genetic components, environmental causes, and immunopathologic signatures, and are broadly characterized into type 2-high or type 2-low (non-type 2) endotypes by linking clinical characteristics, steroid responsiveness, and molecular pathways. Regardless of asthma severity and adequate disease management, patients may experience acute exacerbations of symptoms and a loss of disease control, often triggered by respiratory infections. The interferon (IFN) family represents a group of cytokines that play a central role in the protection against and exacerbation of various infections and pathologies, including asthma. Type I and III IFNs in particular play an indispensable role in the host immune system to fight off pathogens, which seems to be altered in both pediatric and adult asthmatics. Impaired IFN production leaves asthmatics susceptible to infection and with uncontrolled type 2 immunity, promotes airway hyperresponsiveness (AHR), and inflammation which can lead to asthma exacerbations. However, IFN deficiency is not observed in all asthmatics, and alterations in IFN expression may be independent of type 2 immunity. In this review, we discuss the link between type I and III IFNs and asthma both in general and in specific contexts, including during viral infection, co-infection, and bacterial/fungal infection. We also highlight several studies which examine the potential role for type I and III IFNs as asthma-related therapies.

Decoding Susceptibility to Respiratory Viral Infections and Asthma Inception in Children

Human Respiratory Syncytial Virus and Human Rhinovirus are the most frequent cause of respiratory tract infections in infants and children and are major triggers of acute viral bronchiolitis, wheezing and asthma exacerbations. Here, we will discuss the application of the powerful tools of systems biology to decode the molecular mechanisms that determine risk for infection and subsequent asthma. An important conceptual advance is the understanding that the innate immune system is governed by a Bow-tie architecture, where diverse input signals converge onto a few core pathways (e.g., IRF7), which in turn generate diverse outputs that orchestrate effector and regulatory functions. Molecular profiling studies in children with severe exacerbations of asthma/wheeze have identified two major immunological phenotypes. The IRF7hi phenotype is characterised by robust upregulation of antiviral response networks, and the IRF7lo phenotype is characterised by upregulation of markers of TGFβ signalling and type 2 inflammation. Similar phenotypes have been identified in infants and children with severe viral bronchiolitis. Notably, genome-wide association studies supported by experimental validation have identified key pathways that increase susceptibility to HRV infection (ORMDL3 and CHDR3) and modulate TGFβ signalling (GSDMB, TGFBR1, and SMAD3). Moreover, functional deficiencies in the activation of type I and III interferon responses are already evident at birth in children at risk of developing febrile lower respiratory tract infections and persistent asthma/wheeze, suggesting that the trajectory to asthma begins at birth or in utero. Finally, exposure to microbes and their products reprograms innate immunity and provides protection from the development of allergies and asthma in children, and therefore microbial products are logical candidates for the primary prevention of asthma.

The IL-17 receptor IL-17RE mediates polyIC-induced exacerbation of experimental allergic asthma

BACKGROUND

The interleukin 17 receptor E (IL-17RE) is specific for the epithelial cytokine interleukin-17C (IL-17C). Asthma exacerbations are frequently caused by viral infections. Polyinosinic:polycytidylic acid (pIC) mimics viral infections through binding to pattern recognition receptors (e.g. TLR-3). We and others have shown that pIC induces the expression of IL-17C in airway epithelial cells. Using different mouse models, we aimed to investigate the function of IL-17RE in the development of experimental allergic asthma and acute exacerbation thereof.

METHODS

Wild-type (WT) and IL-17RE deficient (Il-17re-/-) mice were sensitized and challenged with OVA to induce allergic airway inflammation. pIC or PBS were applied intranasally when allergic airway inflammation had been established. Pulmonary expression of inflammatory mediators, numbers of inflammatory cells, and airway hyperresponsiveness (AHR) were analyzed.

RESULTS

Ablation of IL-17RE did not affect the development of OVA-induced allergic airway inflammation and AHR. pIC induced inflammation independent of IL-17RE in the absence of allergic airway inflammation. Treatment of mice with pIC exacerbated pulmonary inflammation in sensitized and OVA-challenged mice in an IL-17RE-dependent manner. The pIC-induced expression of cytokines (e.g. keratinocyte-derived chemokine (KC), granulocyte-colony stimulating factor (G-CSF)) and recruitment of neutrophils were decreased in Il-17re-/- mice. pIC-exacerbated AHR was partially decreased in Il-17re-/- mice.

CONCLUSIONS

Our results indicate that IL-17RE mediates virus-triggered exacerbations but does not have a function in the development of allergic lung disease.

Rhinovirus Species-Specific Antibodies Differentially Reflect Clinical Outcomes in Health and Asthma

Rationale: Rhinoviruses (RVs) are major triggers of common cold and acute asthma exacerbations. RV species A, B, and C may have distinct clinical impact; however, little is known regarding RV species-specific antibody responses in health and asthma.Objectives: To describe and compare total and RV species-specific antibody levels in healthy children and children with asthma, away from an acute event.Methods: Serum samples from 163 preschool children with mild to moderate asthma and 72 healthy control subjects from the multinational Predicta cohort were analyzed using the recently developed PreDicta RV antibody chip.Measurements and Main Results: RV antibody levels varied, with RV-C and RV-A being higher than RV-B in both groups. Compared with control subjects, asthma was characterized by significantly higher levels of antibodies to RV-A and RV-C, but not RV-B. RV antibody levels positively correlated with the number of common colds over the previous year in healthy children, and wheeze episodes in children with asthma. Antibody levels also positively correlated with asthma severity but not with current asthma control.Conclusions: The variable humoral response to RV species in both groups suggests a differential infectivity pattern between RV species. In healthy preschoolers, RV antibodies accumulate with colds. In asthma, RV-A and RV-C antibodies are much higher and further increase with disease severity and wheeze episodes. Higher antibody levels in asthma may be caused by a compromised innate immune response, leading to increased exposure of the adaptive immune response to the virus. Importantly, there is no apparent protection with increasing levels of antibodies.

Respiratory microbiome and epithelial interactions shape immunity in the lungs

The airway epithelium represents a physical barrier to the external environment acting as the first line of defence against potentially harmful environmental stimuli including microbes and allergens. However, lung epithelial cells are increasingly recognized as active effectors of microbial defence, contributing to both innate and adaptive immune function in the lower respiratory tract. These cells express an ample repertoire of pattern recognition receptors with specificity for conserved microbial and host motifs. Modern molecular techniques have uncovered the complexity of the lower respiratory tract microbiome. The interaction between the microbiota and the airway epithelium is key to understanding how stable immune homeostasis is maintained. Loss of epithelial integrity following exposure to infection can result in the onset of inflammation in susceptible individuals and may culminate in lung disease. Here we discuss the current knowledge regarding the molecular and cellular mechanisms by which the pulmonary epithelium interacts with the lung microbiome in shaping immunity in the lung. Specifically, we focus on the interactions between the lung microbiome and the cells of the conducting airways in modulating immune cell regulation, and how defects in barrier structure and function may culminate in lung disease. Understanding these interactions is fundamental in the search for more effective therapies for respiratory diseases.

Airway Epithelial Cell Immunity Is Delayed During Rhinovirus Infection in Asthma and COPD

Respiratory viral infections, particularly those caused by rhinovirus, exacerbate chronic respiratory inflammatory diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Airway epithelial cells are the primary site of rhinovirus replication and responsible of initiating the host immune response to infection. Numerous studies have reported that the anti-viral innate immune response (including type I and type III interferon) in asthma is less effective or deficient leading to the conclusion that epithelial innate immunity is a key determinant of disease severity during a rhinovirus induced exacerbation. However, deficient rhinovirus-induced epithelial interferon production in asthma has not always been observed. We hypothesized that disparate in vitro airway epithelial infection models using high multiplicity of infection (MOI) and lacking genome-wide, time course analyses have obscured the role of epithelial innate anti-viral immunity in asthma and COPD. To address this, we developed a low MOI rhinovirus model of differentiated primary epithelial cells obtained from healthy, asthma and COPD donors. Using genome-wide gene expression following infection, we demonstrated that gene expression patterns are similar across patient groups, but that the kinetics of induction are delayed in cells obtained from asthma and COPD donors. Rhinovirus-induced innate immune responses were defined by interferons (type-I, II, and III), interferon response factors (IRF1, IRF3, and IRF7), TLR signaling and NF-κB and STAT1 activation. Induced gene expression was evident at 24 h and peaked at 48 h post-infection in cells from healthy subjects. In contrast, in cells from donors with asthma or COPD induction was maximal at or beyond 72–96 h post-infection. Thus, we propose that propensity for viral exacerbations of asthma and COPD relate to delayed (rather than deficient) expression of epithelial cell innate anti-viral immune genes which in turns leads to a delayed and ultimately more inflammatory host immune response.

The Role of Lung and Gut Microbiota in the Pathology of Asthma

Asthma is a common chronic respiratory disease affecting more than 300 million people worldwide. Clinical features of asthma and its immunological and molecular etiology vary significantly among patients. An understanding of the complexities of asthma has evolved to the point where precision medicine approaches, including microbiome analysis, are being increasingly recognized as an important part of disease management. Lung and gut microbiota play several important roles in the development, regulation, and maintenance of healthy immune responses. Dysbiosis and subsequent dysregulation of microbiota-related immunological processes affect the onset of the disease, its clinical characteristics, and responses to treatment. Bacteria and viruses are the most extensively studied microorganisms relating to asthma pathogenesis, but other microbes, including fungi and even archaea, can potently influence airway inflammation. This review focuses on recently discovered connections between lung and gut microbiota, including bacteria, fungi, viruses, and archaea, and their influence on asthma.

M1-like macrophages are potent producers of anti-viral interferons and M1-associated marker-positive lung macrophages are decreased during rhinovirus-induced asthma exacerbations

BACKGROUND

Macrophages (Mф) can be M1/M2 polarized by Th1/2 signals, respectively. M2-like Mф are thought to be important in asthma pathogenesis, and M1-like in anti-infective immunity, however their roles in virus-induced asthma exacerbations are unknown. Our objectives were (i) to assess polarised Mф phenotype responses to rhinovirus (RV) infection in vitro and (ii) to assess Mф phenotypes in healthy subjects and people with asthma before and during experimental RV infection in vivo.

METHODS

We investigated characteristics of polarized/unpolarized human monocyte-derived Mф (MDM, from 3-6 independent donors) in vitro and evaluated frequencies of M1/M2-like bronchoalveolar lavage (BAL) Mф in experimental RV-induced asthma exacerbation in 7 healthy controls and 17 (at baseline) and 18 (at day 4 post infection) people with asthma.

FINDINGS

We observed in vitro: M1-like but not M2-like or unpolarized MDM are potent producers of type I and III interferons in response to RV infection (P<0.0001), and M1-like are more resistant to RV infection (P<0.05); compared to M1-like, M2-like MDM constitutively produced higher levels of CCL22/MDC (P = 0.007) and CCL17/TARC (P<0.0001); RV-infected M1-like MDM were characterized as CD14+CD80+CD197+ (P = 0.002 vs M2-like, P<0.0001 vs unpolarized MDM). In vivo we found reduced percentages of M1-like CD14+CD80+CD197+ BAL Mф in asthma during experimental RV16 infection compared to baseline (P = 0.024).

INTERPRETATION

Human M1-like BAL Mф are likely important contributors to anti-viral immunity and their numbers are reduced in patients with allergic asthma during RV-induced asthma exacerbations. This mechanism may be one explanation why RV-triggered clinical and pathologic outcomes are more severe in allergic patients than in healthy subjects.

FUNDING

ERC FP7 Advanced grant 233015, MRC Centre Grant G1000758, Asthma UK grant 08-048, NIHR Biomedical Research Centre funding scheme, NIHR BRC Centre grant P26095, the Predicta FP7 Collaborative Project grant 260895, RSF grant 19-15-00272, Megagrant No 14.W03.31.0024.

Ginseng alleviates microbial infections of the respiratory tract: a review

The detrimental impact of air pollution as a result of frequent exposure to fine particles posed a global public health risk mainly to the pulmonary disorders in pediatric and geriatric population. Here, we reviewed the current literature regarding the role of ginseng and/or its components as antimicrobials, especially against pathogens that cause respiratory infections in animal and in vitro models. Some of the possible mechanisms for ginseng-mediated viral inhibition suggested are improvements in systemic and mucosa-specific antibody responses, serum hemagglutinin inhibition, lymphocyte proliferation, cell survival rate, and viral clearance in the lungs. In addition, ginseng reduces the expression levels of proinflammatory cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-5, IL-6, IL-8) and chemokines produced by airway epithelial cells and macrophages, thus preventing weight loss. In case of bacterial infections, ginseng acts by alleviating inflammatory cytokine production, increasing survival rates, and activating phagocytes and natural killer cells. In addition, ginseng inhibits biofilm formation and induces the dispersion and dissolution of mature biofilms. Most clinical trials revealed that ginseng, at various dosages, is a safe and effective method of seasonal prophylaxis, relieving the symptoms and reducing the risk and duration of colds and flu. Taken together, these findings support the efficacy of ginseng as a therapeutic and prophylactic agent for respiratory infections.

Prevalence and contribution of respiratory viruses in the community to rates of emergency department visits and hospitalizations with respiratory tract infections, chronic obstructive pulmonary disease and asthma

Background

The individual and combined contribution of viral prevalence in the community to Emergency Department (ED) visits and hospitalizations with respiratory tract infections (RTIs), chronic obstructive pulmonary disease (COPD) and asthma is unclear.

Methods

A retrospective analysis on daily viral positive tests and daily ED visits and hospitalizations between 01/01/2003 to 31/12/2013 in Ontario, Canada. Viral data was collected from the Centre for Immunization and Respiratory Infectious Diseases (CIRID). The Canadian Institute for Health Information reports daily ED visits and hospitalizations for RTIs, COPD and asthma as a primary diagnosis.

Results

There were 4,365,578 ED visits with RTIs of which 321,719 (7.4%) were admitted to hospital; 817,141 ED visits for COPD of which 260,665 (31.9%) were admitted and 649,666 ED visits with asthma of which 68,626 (10.6%) were admitted. The percentage of positive tests to influenza A and B, respiratory syncytial virus (RSV), parainfluenza and adenovirus prevalence explained 57.4% of ED visits and 63.8% of hospitalizations for RTI, 41.4% of ED visits and 39.2% of hospitalizations with COPD but only 1.5% of ED visits and 2.7% of hospitalizations for asthma. The further addition of human metapneumovirus, rhinovirus and coronavirus over the final 3 years accounted for 66.7% of ED visits and 74.4% of hospitalizations for RTI, 52.5% of visits and 48.2% of hospitalizations for COPD, and only 13.3% of visits and 10.4% of hospitalizations for asthma.

Conclusions

Community respiratory viral epidemics are major drivers of ED visits and hospitalizations with RTIs and COPD but only a modest contributor to asthma.

Pseudomonas aeruginosa Modulates the Antiviral Response of Bronchial Epithelial Cells

Cystic fibrosis (CF) patients frequently acquire Pseudomonas aeruginosa infections that have been associated with a bad prognosis and an increased rate of pulmonary exacerbations. Respiratory viruses can cause exacerbations in chronic pulmonary diseases including COPD or asthma and have been suggested to contribute to exacerbations also in CF. In this study we investigated a possible link between P. aeruginosa infection and susceptibility to respiratory viruses. We show that P. aeruginosa is able to block the antiviral response of airway epithelial cells thereby promoting virus infection and spread. Mechanistically, P. aeruginosa secretes the protease AprA in a LasR dependent manner, which is able of directly degrading epithelial-derived IFNλ resulting in inhibition of IFN signaling. In addition, we correlate the virus infection status of CF patients with the ability of patients' P. aeruginosa isolates to degrade IFNλ. In line with this, the infection status of CF patients correlated significantly with the amount of respiratory viruses in sputum. Our data suggest that the interplay between P. aeruginosa and respiratory virus infections might partially explain the association of increased rates of pulmonary exacerbations and P. aeruginosa infections in CF patients.

Focus on the cetirizine use in clinical practice: a reappraisal 30 years later

Antihistamines are currently one of the most commonly administered categories of drugs. They are used to treat symptoms that are secondary to histamine release, which is typical of certain allergic conditions, including rhinitis, conjunctivitis, asthma, urticaria, and anaphylaxis. Cetirizine belongs to the second-generation family, so, it is very selective for peripheral H1 receptors, is potent and quickly relieves symptoms, exerts additional anti-allergic/anti-inflammatory effects, and is usually well-tolerated. It has been marketed 30 years ago. In these years, a remarkable body of evidence has been built. The current review provides a practical update on the use of cetirizine in clinical practice.

Intensified Therapy with Inhaled Corticosteroids and Long-Acting β2-Agonists at the Onset of Upper Respiratory Tract Infection to Prevent Chronic Obstructive Pulmonary Disease Exacerbations. A Multicenter, Randomized, Double-Blind, Placebo-controlled Trial

RATIONALE

The efficacy of intensified combination therapy with inhaled corticosteroids (ICS) and long-acting β₂-agonists (LABA) at the onset of upper respiratory tract infection (URTI) symptoms in chronic obstructive pulmonary disease (COPD) is unknown.

OBJECTIVES

To evaluate whether intensified combination therapy with ICS/LABA, at the onset of URTI symptoms, decreases the incidence of COPD exacerbation occurring within 21 days of the URTI.

METHODS

A total of 450 patients with stable, moderate to very severe COPD, were included in this investigator-initiated and -driven, double-blind, randomized, placebo-controlled study. At inclusion, patients were assigned to open-labeled low-maintenance dose ICS/LABA. Each patient was randomized either to intensified-dose ICS/LABA or placebo and instructed to start using this medication only in case of a URTI, at the onset of symptoms, twice daily, for 10 days.

MEASUREMENTS AND MAIN RESULTS

The incidence of any exacerbation following a URTI was not significantly decreased in the ICS/LABA group, as compared with placebo (14.6% vs. 16.2%; hazard ratio, 0.77; 95% confidence interval, 0.46-1.33; P = 0.321) but the risk of severe exacerbation was decreased by 72% (hazard ratio, 0.28; 95% confidence interval, 0.11-0.74%; P = 0.010). In the stratified analysis, effect size was modified by disease severity, fractional exhaled nitric oxide, and the body mass index-airflow obstruction-dyspnea, and exercise score. Compared with the stable period, evidence of at least one virus was significantly more common at URTI, 10 days after URTI, and at exacerbation.

CONCLUSIONS

Intensified combination therapy with ICS/LABA for 10 days at URTI onset did not decrease the incidence of any COPD exacerbation but prevented severe exacerbation. Patients with more severe disease had a significant risk reduction for any exacerbation. Clinical trial registered with www.isrctn.com (ISRCTN45572998).

Rhinovirus and Asthma Exacerbations

Rhinovirus (RV) is ubiquitous and typically causes only minor upper respiratory symptoms. However, especially in children and adolescent asthmatics, RV is responsible for most exacerbations. This ability of RV to drive exacerbations typically requires the concomitant presence of exposure to a bystander allergen. Susceptibility to RV-mediated exacerbations is also related to the genetic background of the host, which contributes to greater infectivity, more severe infections, altered immune responses, and to greater inflammation and loss of asthma control. Given these responses, there are several treatments available or being developed that should improve the control of exacerbations related to RV infection.

Asthma: An Undermined State of Immunodeficiency

Asthma is a heterogeneous chronic respiratory disease characterized by an increased burden of infections. Respiratory tract infections associated with an increased risk for asthma especially when occurring in the first months of life, also represent the most common cause of asthma exacerbations. The association between asthma and the increased frequency of infections and microbiota dysbiosis might be explained by a common mechanism, such as an underlying immune system defect. Apart from the well-established association between primary immunodeficiencies and asthma, several alterations in the immune response following infection have also been observed in asthmatic patients. An impairment in lung epithelial barrier integrity exists and is associated with both an increased susceptibility to infections and the development of asthma. Asthmatic patients are also found to have a deficient interferon (IFN) response upon infection. Additionally, defects in Toll-like receptor (TLR) signaling are observed in asthma and are correlated with both recurrent infections and asthma development. In this review, we summarize the common pathophysiological background of asthma and infections, highlighting the importance of an underlying immune system defect that predispose individuals to recurrent infections and asthma.

Upper Airway Cell Transcriptomics Identify a Major New Immunological Phenotype with Strong Clinical Correlates in Young Children with Acute Wheezing

Asthma exacerbations are triggered by rhinovirus infections. We employed a systems biology approach to delineate upper-airway gene network patterns underlying asthma exacerbation phenotypes in children. Cluster analysis unveiled distinct IRF7^hi versus IRF7^lo molecular phenotypes, the former exhibiting robust upregulation of Th1/type I IFN responses and the latter an alternative signature marked by upregulation of cytokine and growth factor signaling and downregulation of IFN-γ. The two phenotypes also produced distinct clinical phenotypes. For IRF7^lo children, symptom duration prior to hospital presentation was more than twice as long from initial symptoms (p = 0.011) and nearly three times as long for cough (p < 0.001), the odds ratio of admission to hospital was increased more than 4-fold (p = 0.018), and time to recurrence was shorter (p = 0.015). In summary, our findings demonstrate that asthma exacerbations in children can be divided into IRF7^hi versus IRF7^lo phenotypes with associated differences in clinical phenotypes.

Pelargonium sidoides radix extract EPs 7630 reduces rhinovirus infection through modulation of viral binding proteins on human bronchial epithelial cells

Bronchial epithelial cells are the first target cell for rhinovirus infection. The course of viral infections in patients with acute bronchitis, asthma and COPD can be improved by oral application of Pelargonium sidoides radix extract; however, the mechanism is not well understood. This study investigated the in vitro effect of Pelargonium sidoides radix extract (EPs 7630) on the expression of virus binding cell membrane and host defence supporting proteins on primary human bronchial epithelial cells (hBEC). Cells were isolated from patients with severe asthma (n = 6), moderate COPD (n = 6) and non-diseased controls (n = 6). Protein expression was determined by Western-blot and immunofluorescence. Rhinovirus infection was determined by immunofluorescence as well as by polymerase chain reaction. Cell survival was determined by manual cell count after live/death immunofluorescence staining. All parameters were determined over a period of 3 days. The results show that EPs 7630 concentration-dependently and significantly increased hBEC survival after rhinovirus infection. This effect was paralleled by decreased expression of the inducible co-stimulator (ICOS), its ligand ICOSL and cell surface calreticulin (C1qR). In contrast, EPs 7630 up-regulated the expression of the host defence supporting proteins β-defensin-1 and SOCS-1, both in rhinovirus infected and un-infected hBEC. The expression of other virus interacting cell membrane proteins such as MyD88, TRL2/4 or ICAM-1 was not altered by EPs 7630. The results indicate that EPs 7630 may reduce rhinovirus infection of human primary BEC by down-regulating cell membrane docking proteins and up-regulating host defence proteins.

Immunodeficiency in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), characterized by progressive airway inflammation and irreversible airflow limitation, leads to serious decline in life quality. The acute exacerbation of COPD (AECOPD) results in high healthcare costs as well as a significant mortality rate. The most common cause of acute exacerbation is infection. Immune deficiency, which induces dysfunction of anti-infection, plays an important role in the pathogenesis of acute exacerbation. As described in this review, the immune dysfunction in patients with AECOPD can be a major focus of efforts to therapeutic strategy.

Nucleic Acid Sensing in Allergic Disorders

Recent advances indicate that there is crosstalk between allergic disorders and nucleic acid sensing. Triggers that activate inflammatory mechanisms via nucleic acid sensors affect both allergic phenotypes and anti-viral responses, depending on the timing and the order of exposure. Viral respiratory infections, such as those caused by the rhinovirus, influenza, and respiratory syncytial virus, are the most frequent cause of significant asthma exacerbations through effects mediated predominantly by TLR3. However, agonists of other nucleic acid sensors, such as TLR7/8 and TLR9 agonists, may inhibit allergic inflammation and reduce clinical manifestations of disease. The allergic state can predispose the immune system to both exaggerated responses to viral infections or protection from anti-viral inflammatory responses. T_H2 cytokines appear to alter the epithelium, leading to defective viral clearance or exaggerated responses to viral infections. However, a T_H2 skewed allergic response may be protective against a T_H1-dependent inflammatory anti-viral response. This review briefly introduces the receptors involved in nucleic acid sensing, addresses mechanisms by which nucleic acid sensing and allergic responses can counteract one another, and discusses the strategies in experimental settings, both in animal and human studies, to harness the nucleic acid sensing machinery for the intervention of allergic disorders.

Lower Airway Virology in Health and Disease-From Invaders to Symbionts

Studies of human airway virome are relatively recent and still very limited. Culture-independent microbial techniques showed growing evidence of numerous viral communities in the respiratory microbial ecosystem. The significance of different acute respiratory viruses is already known in the pathogenesis of chronic conditions, such as asthma, cystic fibrosis (CF), or chronic obstructive lung disease (COPD), and their exacerbations. Viral pathogens, such as influenza, metapneumovirus, parainfluenza, respiratory syncytial virus, or rhinovirus, have been associated with impaired immune response, acute exacerbations, and decrease in lung function in chronic lung diseases. However, more data have attributed a role to Herpes family viruses or the newly identified Anelloviridae family of viruses in chronic diseases, such as asthma, idiopathic pulmonary fibrosis (IPF), or CF. Impaired antiviral immunity, bacterial colonization, or used medication, such as glucocorticoids or antibiotics, contribute to the imbalance of airway microbiome and may shape the local viral ecosystem. A specific part of virome, bacteriophages, frames lung microbial communities through direct contact with its host, the specific bacteria known as Pseudomonas aeruginosa or their biofilm formation. Moreover, antibiotic resistance is induced through phages via horizontal transfer and leads to more severe exacerbations of chronic airway conditions. Morbidity and mortality of asthma, COPD, CF, and IPF remains high, despite an increased understanding and knowledge about the impact of respiratory virome in the pathogenesis of these conditions. Thus, more studies focus on new prophylactic methods or therapeutic agents directed toward viral⁻host interaction, microbial metabolic function, or lung microbial composition rearrangement.

Recent advances in understanding rhinovirus immunity

Rhinoviruses are the most common cause of upper respiratory tract infections. However, they can induce exacerbations of chronic obstructive pulmonary disease and asthma, bronchiolitis in infants, and significant lower respiratory tract infections in children, the immunosuppressed, and the elderly. The large number of rhinovirus strains (currently about 160) and their antigenic diversity are significant obstacles in vaccine development. The phenotype of immune responses induced during rhinovirus infection can affect disease severity. Recognition of rhinovirus and a balance of innate responses are important factors in rhinovirus-induced morbidity. Immune responses to rhinovirus infections in healthy individuals are typically of the T helper type 1 (Th1) phenotype. However, rhinovirus-driven asthma exacerbations are additionally characterised by an amplified Th2 immune response and airway neutrophilia. This commentary focuses on recent advances in understanding immunity toward rhinovirus infection and how innate and adaptive immune responses drive rhinovirus-induced asthma exacerbations.

The human viral challenge model: accelerating the evaluation of respiratory antivirals, vaccines and novel diagnostics

The Human Viral Challenge (HVC) model has, for many decades, helped in the understanding of respiratory viruses and their role in disease pathogenesis. In a controlled setting using small numbers of volunteers removed from community exposure to other infections, this experimental model enables proof of concept work to be undertaken on novel therapeutics, including vaccines, immunomodulators and antivirals, as well as new diagnostics.Crucially, unlike conventional phase 1 studies, challenge studies include evaluable efficacy endpoints that then guide decisions on how to optimise subsequent field studies, as recommended by the FDA and thus licensing studies that follow. Such a strategy optimises the benefit of the studies and identifies possible threats early on, minimising the risk to subsequent volunteers but also maximising the benefit of scarce resources available to the research group investing in the research. Inspired by the principles of the 3Rs (Replacement, Reduction and Refinement) now commonly applied in the preclinical phase, HVC studies allow refinement and reduction of the subsequent development phase, accelerating progress towards further statistically powered phase 2b studies. The breadth of data generated from challenge studies allows for exploration of a wide range of variables and endpoints that can then be taken through to pivotal phase 3 studies.We describe the disease burden for acute respiratory viral infections for which current conventional development strategies have failed to produce therapeutics that meet clinical need. The Authors describe the HVC model's utility in increasing scientific understanding and in progressing promising therapeutics through development.The contribution of the model to the elucidation of the virus-host interaction, both regarding viral pathogenicity and the body's immunological response is discussed, along with its utility to assist in the development of novel diagnostics.Future applications of the model are also explored.

Anti-Allergic Inflammatory Activity of Interleukin-37 Is Mediated by Novel Signaling Cascades in Human Eosinophils

IL-1 family regulatory cytokine IL-37b can suppress innate immunity and inflammatory activity in inflammatory diseases. In this study, IL-37b showed remarkable in vitro suppression of inflammatory tumor necrosis factor-α, IL-1β, IL-6, CCL2, and CXCL8 production in the coculture of human primary eosinophils and human bronchial epithelial BEAS-2B cells with the stimulation of bacterial toll-like receptor-2 ligand peptidoglycan, while antagonizing the activation of intracellular nuclear factor-κB, PI3K–Akt, extracellular signal-regulated kinase 1/2, and suppressing the gene transcription of allergic inflammation-related PYCARD, S100A9, and CAMP as demonstrated by flow cytometry, RNA-sequencing, and bioinformatics. Results therefore elucidated the novel anti-inflammation-related molecular mechanisms mediated by IL-37b. Using the house dust mite (HDM)-induced humanized asthmatic NOD/SCID mice for preclinical study, intravenous administration of IL-37b restored the normal plasma levels of eosinophil activators CCL11 and IL-5, suppressed the elevated concentrations of Th2 and asthma-related cytokines IL-4, IL-6, and IL-13 and inflammatory IL-17, CCL5, and CCL11 in lung homogenate of asthmatic mice. Histopathological results of lung tissue illustrated that IL-37b could mitigate the enhanced mucus, eosinophil infiltration, thickened airway wall, and goblet cells. Together with similar findings using the ovalbumin- and HDM-induced allergic asthmatic mice further validated the therapeutic potential of IL-37b in allergic asthma. The above results illustrate the novel IL-37-mediated regulation of intracellular inflammation mechanism linking bacterial infection and the activation of human eosinophils and confirm the in vivo anti-inflammatory activity of IL-37b on human allergic asthma.

Fragment-derived inhibitors of human N-myristoyltransferase block capsid assembly and replication of the common cold virus

Rhinoviruses (RVs) are the pathogens most often responsible for the common cold, and are a frequent cause of exacerbations in asthma, chronic obstructive pulmonary disease and cystic fibrosis. Here we report the discovery of IMP-1088, a picomolar dual inhibitor of the human N-myristoyltransferases NMT1 and NMT2, and use it to demonstrate that pharmacological inhibition of host-cell N-myristoylation rapidly and completely prevents rhinoviral replication without inducing cytotoxicity. The identification of cooperative binding between weak-binding fragments led to rapid inhibitor optimization through fragment reconstruction, structure-guided fragment linking and conformational control over linker geometry. We show that inhibition of the co-translational myristoylation of a specific virus-encoded protein (VP0) by IMP-1088 potently blocks a key step in viral capsid assembly, to deliver a low nanomolar antiviral activity against multiple RV strains, poliovirus and foot and-mouth disease virus, and protection of cells against virus-induced killing, highlighting the potential of host myristoylation as a drug target in picornaviral infections.