Effects of rhinovirus species on viral replication and cytokine production

Assessing Immune Factors in Maternal Milk and Paired Infant Plasma Antibody Binding to Human Rhinoviruses

Before they can produce their own antibodies, newborns are protected from infections by transplacental transfer of maternal IgG antibodies and after birth through breast milk IgA antibodies. Rhinovirus (RV) infections are extremely common in early childhood, and while RV infections often result in only mild upper respiratory illnesses, they can also cause severe lower respiratory illnesses such as bronchiolitis and pneumonia. We used high-density peptide arrays to profile infant and maternal antibody reactivity to capsid and full proteome sequences of three human RVs - A16, B52, and C11. Numerous plasma IgG and breast milk IgA RV epitopes were identified that localized to regions of the RV capsid surface and interior, and also to several non-structural proteins. While most epitopes were bound by both IgG and IgA, there were several instances where isotype-specific and RV-specific binding were observed. We also profiled 62 unique RV-C dominant protein loop sequences characteristic of this species' capsid VP1 protein. Many of these RV-C sites were highly bound by IgG from one-year-old infants, indicating recent or ongoing active infections, or alternatively, a level of cross-reactivity among homologous RV-C sites.

The Picornaviridae Family: Knowledge Gaps, Animal Models, Countermeasures, and Prototype Pathogens

Picornaviruses are nonenveloped particles with a single-stranded RNA genome of positive polarity. This virus family includes poliovirus, hepatitis A virus, rhinoviruses, and Coxsackieviruses. Picornaviruses are common human pathogens, and infection can result in a spectrum of serious illnesses, including acute flaccid myelitis, severe respiratory complications, and hand-foot-mouth disease. Despite research on poliovirus establishing many fundamental principles of RNA virus biology and the first transgenic animal model of disease for infection by a human virus, picornaviruses are understudied. Existing knowledge gaps include, identification of molecules required for virus entry, understanding cellular and humoral immune responses elicited during virus infection, and establishment of immune-competent animal models of virus pathogenesis. Such knowledge is necessary for development of pan-picornavirus countermeasures. Defining enterovirus A71 and D68, human rhinovirus C, and echoviruses 29 as prototype pathogens of this virus family may provide insight into picornavirus biology needed to establish public health strategies necessary for pandemic preparedness.

Viral infections and chronic rhinosinusitis

Viral infections are the most common cause of upper respiratory infections; they frequently infect adults once or twice and children 6 to 8 times annually. In most cases, these infections are self-limiting and resolve. However, many patients with chronic rhinosinusitis (CRS) relay that their initiating event began with an upper respiratory infection that progressed in both symptom severity and duration. Viruses bind to sinonasal epithelia through specific receptors, thereby entering cells and replicating within them. Viral infections stimulate interferon-mediated innate immune responses. Recent studies suggest that viral infections may also induce type 2 immune responses and stimulate the aberrant production of cytokines that can result in loss of barrier function, which is a hallmark in CRS. The main purpose of this review will be to highlight common viruses and their associated binding receptors and highlight pathophysiologic mechanisms associated with alterations in mucociliary clearance, epithelial barrier function, and dysfunctional immune responses that might lead to a further understanding of the pathogenesis of CRS.

Rhinovirus induces airway remodeling: what are the physiological consequences?

BACKGROUND

Rhinovirus infections commonly evoke asthma exacerbations in children and adults. Recurrent asthma exacerbations are associated with injury-repair responses in the airways that collectively contribute to airway remodeling. The physiological consequences of airway remodeling can manifest as irreversible airway obstruction and diminished responsiveness to bronchodilators. Structural cells of the airway, including epithelial cells, smooth muscle, fibroblasts, myofibroblasts, and adjacent lung vascular endothelial cells represent an understudied and emerging source of cellular and extracellular soluble mediators and matrix components that contribute to airway remodeling in a rhinovirus-evoked inflammatory environment.

MAIN BODY

While mechanistic pathways associated with rhinovirus-induced airway remodeling are still not fully characterized, infected airway epithelial cells robustly produce type 2 cytokines and chemokines, as well as pro-angiogenic and fibroblast activating factors that act in a paracrine manner on neighboring airway cells to stimulate remodeling responses. Morphological transformation of structural cells in response to rhinovirus promotes remodeling phenotypes including induction of mucus hypersecretion, epithelial-to-mesenchymal transition, and fibroblast-to-myofibroblast transdifferentiation. Rhinovirus exposure elicits airway hyperresponsiveness contributing to irreversible airway obstruction. This obstruction can occur as a consequence of sub-epithelial thickening mediated by smooth muscle migration and myofibroblast activity, or through independent mechanisms mediated by modulation of the β2 agonist receptor activation and its responsiveness to bronchodilators. Differential cellular responses emerge in response to rhinovirus infection that predispose asthmatic individuals to persistent signatures of airway remodeling, including exaggerated type 2 inflammation, enhanced extracellular matrix deposition, and robust production of pro-angiogenic mediators.

CONCLUSIONS

Few therapies address symptoms of rhinovirus-induced airway remodeling, though understanding the contribution of structural cells to these processes may elucidate future translational targets to alleviate symptoms of rhinovirus-induced exacerbations.

Advances in the Relationship between Respiratory Viruses and Asthma

Several studies have reported that viral infection is closely associated with the onset, progression, and exacerbation of asthma. The purpose of this review is to summarize the role that viral infections have in the pathogenesis of asthma onset and exacerbations, as well as discuss interrelated protective and risk factors of asthma and current treatment options. Furthermore, we present current knowledge of the innate immunological pathways driving host defense, including changes in the epithelial barrier. In addition, we highlight the importance of the genetics and epigenetics of asthma and virus susceptibility. Moreover, the involvement of virus etiology from bronchiolitis and childhood wheezing to asthma is described. The characterization and mechanisms of action of the respiratory viruses most frequently related to asthma are mentioned.

Rhinoviruses A and C elicit long-lasting antibody responses with limited cross-neutralization

Rhinoviruses (RVs) can cause severe wheezing illnesses in young children and patients with asthma. Vaccine development has been hampered by the multitude of RV types with little information about cross-neutralization. We previously showed that neutralizing antibody (nAb) responses to RV-C are detected twofold to threefold more often than those to RV-A throughout childhood. Based on those findings, we hypothesized that RV-C infections are more likely to induce either cross-neutralizing or longer-lasting antibody responses compared with RV-A infections. We pooled RV diagnostic data from multiple studies of children with respiratory illnesses and compared the expected versus observed frequencies of sequential infections with RV-A or RV-C types using log-linear regression models. We tested longitudinally collected plasma samples from children to compare the duration of RV-A versus RV-C nAb responses. Our models identified limited reciprocal cross-neutralizing relationships for RV-A (A12-A75, A12-A78, A20-A78, and A75-A78) and only one for RV-C (C2-C40). Serologic analysis using reference mouse sera and banked human plasma samples confirmed that C40 infections induced nAb responses with modest heterotypic activity against RV-C2. Mixed-effects regression modeling of longitudinal human plasma samples collected from ages 2 to 18 years demonstrated that RV-A and RV-C illnesses induced nAb responses of similar duration. These results indicate that both RV-A and RV-C nAb responses have only modest cross-reactivity that is limited to genetically similar types. Contrary to our initial hypothesis, RV-C species may include even fewer cross-neutralizing types than RV-A, whereas the duration of nAb responses during childhood is similar between the two species. The modest heterotypic responses suggest that RV vaccines must have a broad representation of prevalent types.

Update on virus-induced asthma exacerbations

INTRODUCTION

Viral infections are common triggers for asthma exacerbation. Subjects with asthma are more susceptible to viral infections and develop more severe or long-lasting lower respiratory tract symptoms than healthy individuals owing to impaired immune responses. Of the many viruses associated with asthma exacerbation, rhinovirus (RV) is the most frequently identified virus in both adults and children.

AREAS COVERED

We reviewed epidemiological and clinical links and mechanistic studies on virus-associated asthma exacerbations. We included sections on severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), the latest evidence of coronavirus disease 2019 (COVID-19) in asthma patients, and past and future searches for therapeutic and prevention targets.

EXPERT OPINION

Early treatment or prevention of viral infections might significantly reduce the rate of asthma exacerbation, which is one of the key points of disease management. Although it is hypothetically possible nowadays to interfere with every step of the infectious cycle of respiratory tract viruses, vaccination development has provided some of the most encouraging results. Future research should proceed toward the development of a wider spectrum of vaccines to achieve a better quality of life for patients with asthma and to reduce the economic burden on the healthcare system.

CCL5 is a potential bridge between type 1 and type 2 inflammation in asthma

BACKGROUND

Type 1 (T1) inflammation (marked by IFN-γ expression) is now consistently identified in subsets of asthma cohorts, but how it contributes to disease remains unclear.

OBJECTIVE

We sought to understand the role of CCL5 in asthmatic T1 inflammation and how it interacts with both T1 and type 2 (T2) inflammation.

METHODS

CCL5, CXCL9, and CXCL10 messenger RNA expression from sputum bulk RNA sequencing, as well as clinical and inflammatory data were obtained from the Severe Asthma Research Program III (SARP III). CCL5 and IFNG expression from bronchoalveolar lavage cell bulk RNA sequencing was obtained from the Immune Mechanisms in Severe Asthma (IMSA) cohort and expression related to previously identified immune cell profiles. The role of CCL5 in tissue-resident memory T-cell (TRM) reactivation was evaluated in a T1high murine severe asthma model.

RESULTS

Sputum CCL5 expression strongly correlated with T1 chemokines (P < .001 for CXCL9 and CXCL10), consistent with a role in T1 inflammation. CCL5high participants had greater fractional exhaled nitric oxide (P = .009), blood eosinophils (P < .001), and sputum eosinophils (P = .001) in addition to sputum neutrophils (P = .001). Increased CCL5 bronchoalveolar lavage expression was unique to a previously described T1high/T2variable/lymphocytic patient group in the IMSA cohort, with IFNG trending with worsening lung obstruction only in this group (P = .083). In a murine model, high expression of the CCL5 receptor CCR5 was observed in TRMs and was consistent with a T1 signature. A role for CCL5 in TRM activation was supported by the ability of the CCR5 inhibitor maraviroc to blunt reactivation.

CONCLUSION

CCL5 appears to contribute to TRM-related T1 neutrophilic inflammation in asthma while paradoxically also correlating with T2 inflammation and with sputum eosinophilia.

Recent Clinical Isolates of Enterovirus D68 Have Increased Replication and Induce Enhanced Epithelial Immune Response Compared to the Prototype Fermon Strain

In 2014, enterovirus D68 (EV-D68), previously associated primarily with mild respiratory illness, caused a large outbreak of severe respiratory illness and, in rare instances, paralysis. We compared the viral binding and replication of eight recent EV-D68 clinical isolates collected both before and during the 2014 outbreak and the prototype Fermon strain from 1962 in cultured HeLa cells and differentiated human primary bronchial epithelial cells (BEC) to understand the possible reasons for the change in virus pathogenicity. We selected pairs of closely related isolates from the same phylogenetic clade that were associated with severe vs. asymptomatic infections. We found no significant differences in binding or replication in HeLa cell cultures between the recent clinical isolates. However, in HeLa cells, Fermon had significantly greater binding (2-3 logs) and virus progeny yields (2-4 logs) but a similar level of replication (1.5-2 log increase in viral RNA from 2 h to 24 h post infection) compared to recent isolates. In differentiated BECs, Fermon and the recent EV-D68 isolates had similar levels of binding; however, the recent isolates produced 1.5-2-log higher virus progeny yields than Fermon due to increased replication. Interestingly, no significant differences in replication were identified between the pairs of genetically close recent EV-D68 clinical isolates despite the observed differences in associated disease severity. We then utilized RNA-seq to define the transcriptional responses in BECs infected with four recent EV-D68 isolates, representing major phylogenetic clades, and the Fermon strain. All the tested clinical isolates induced similar responses in BECs; however, numerous upregulated genes in antiviral and pro-inflammatory response pathways were identified when comparing the response to clinical isolates versus Fermon. These results indicate that the recent emergence in severe EV-D68 cases could be explained by an increased replication efficiency and enhanced inflammatory response induced by newly emerged clinical isolates; however, host factors are likely the main determinants of illness severity.

Placental capillary pericytes release excess extracellular vesicles under hypoxic conditions inducing a pro-angiogenic profile in term pregnancy

Pericytes are multifunctional cells wrapped around capillary endothelia, essential for vascular health, development, and blood flow regulation, although their role in human placental chorionic villi has not been fully explored. The second half of normal pregnancy is characterized by a progressive decline in placental and fetal oxygen levels which, by term, comprises a substantial degree of hypoxia. We hypothesized this hypoxia would stimulate pericyte regulation of chorionic villous capillary function. This study's objective was to investigate the role of hypoxia on normal term placental pericytes (PLVP) and their signaling to endothelial cells. First, we confirmed fetoplacental hypoxia at term by a new analysis of umbilical arterial blood oxygen tension of 3,010 healthy singleton neonates sampled at caesarean section and before labor. We then measured the release of cytokines, chemokines, and small extracellular vesicles (PLVPsv), from PLVP cultured at 20%, 8% and 1% O₂. As O₂ levels decreased, secreted cytokines and chemokines [interleukin-6 (IL-6), interleukin-1α (IL-1α) and vascular endothelial growth factor (VEGF)], and small extracellular vesicle markers, (Alix, Syntenin and CD9) increased significantly in the culture supernatants. When primary human umbilical vein endothelial cells (HUVEC) were cultured with PLVPsv, polygon formation, number, and tube formation length was significantly increased compared to cells not treated with PLVPsv, indicating PLVPsv stimulated angiogenesis. We conclude that adding PLVPsv stimulates angiogenesis and vessel stabilization on neighboring endothelial cells in response to hypoxia in term pregnancy compared to no addition of PLVPsv. Our finding that PLVP can release angiogenic molecules via extracellular vesicles in response to hypoxia may apply to other organ systems.

Rhinovirus—A True Respiratory Threat or a Common Inconvenience of Childhood?

A decade-long neglect of rhinovirus as an important agent of disease in humans was primarily due to the fact that they were seen as less virulent and capable of causing only mild respiratory infections such as common cold. However, with an advent of molecular diagnostic methods, an increasing number of reports placed them among the pathogens found in the lower respiratory tract and recognized them as important risk factors for asthma-related pathology in childhood. As the spread of rhinovirus was not severely affected by the implementation of social distancing and other measures during the coronavirus disease 2019 (COVID-19) pandemic, its putative pathogenic role has become even more evident in recent years. By concentrating on children as the most vulnerable group, in this narrative review we first present classification and main traits of rhinovirus, followed by epidemiology and clinical presentation, risk factors for severe forms of the disease, long-term complications and the pathogenesis of asthma, as well as a snapshot of treatment trials and studies. Recent evidence suggests that the rhinovirus is a significant contributor to respiratory illness in both high-risk and low-risk populations of children.

Rhinovirus increases Moraxella catarrhalis adhesion to the respiratory epithelium

Rhinovirus causes many types of respiratory illnesses, ranging from minor colds to exacerbations of asthma. Moraxella catarrhalis is an opportunistic pathogen that is increased in abundance during rhinovirus illnesses and asthma exacerbations and is associated with increased severity of illness through mechanisms that are ill-defined. We used a co-infection model of human airway epithelium differentiated at the air-liquid interface to test the hypothesis that rhinovirus infection promotes M. catarrhalis adhesion and survival on the respiratory epithelium. Initial experiments showed that infection with M. catarrhalis alone did not damage the epithelium or induce cytokine production, but increased trans-epithelial electrical resistance, indicative of increased barrier function. In a co-infection model, infection with the more virulent rhinovirus-A and rhinovirus-C, but not the less virulent rhinovirus-B types, increased cell-associated M. catarrhalis. Immunofluorescent staining demonstrated that M. catarrhalis adhered to rhinovirus-infected ciliated epithelial cells and infected cells being extruded from the epithelium. Rhinovirus induced pronounced changes in gene expression and secretion of inflammatory cytokines. In contrast, M. catarrhalis caused minimal effects and did not enhance RV-induced responses. Our results indicate that rhinovirus-A or C infection increases M. catarrhalis survival and cell association while M. catarrhalis infection alone does not cause cytopathology or epithelial inflammation. Our findings suggest that rhinovirus and M. catarrhalis co-infection could promote epithelial damage and more severe illness by amplifying leukocyte inflammatory responses at the epithelial surface.

Cytokine expression in rhinovirus- vs. respiratory syncytial virus-induced first wheezing episode and its relation to clinical course

Rhinovirus (RV) and respiratory syncytial virus (RSV) are common causes of bronchiolitis. Unlike an RSV etiology, an RV etiology is associated with a markedly increased risk of asthma. We investigated the cytokine profiles of RV- and RSV-induced first wheezing episode and their correlation with prognosis. We recruited 52 sole RV- and 11 sole RSV-affected children with a severe first wheezing episode. Peripheral blood mononuclear cells (PBMCs) were isolated during acute illness and 2 weeks later and stimulated in vitro with anti-CD3/anti-CD28. Culture medium samples were analyzed for 56 different cytokines by multiplex ELISA. Recurrences were prospectively followed for 4 years. In adjusted analyses, the cytokine response from PBMCs in the RV group was characterized by decreased expression of interleukin 1 receptor antagonist (IL-1RA), interleukin 1 beta (IL-1β), and monocyte chemoattractant protein-1 (MCP-1) and increased expression of eosinophil chemotactic protein 2 (eotaxin-2), thymus- and activation-regulated chemokine (TARC), and epithelial-derived neutrophil-activating peptide 78 (ENA-78) in the acute phase and increased expression of fractalkine in the convalescent phase compared to those in the RSV group. An analysis of the change in cytokine expression between study points revealed an increased expression of fractalkine and IL-1β and decreased expression of I-309 (CCL1) and TARC in the RV group compared to those in the RSV group.. Considering hospitalization time, a significant non-adjusted group × cytokine interaction was observed in the levels of interferon gamma (IFN-γ), macrophage-derived chemokine (MDC), IL-1RA, and vascular endothelial growth factor (VEGF), indicating that a higher expression of cytokine was associated with shorter hospitalization time in the RSV group but not in the RV group. A significant interaction was also found in interleukin 6 (IL-6), but the cytokine response was not associated with hospitalization time in the RSV or RV group. In the RV group, increased expression of I-309 (CCL1) and TARC was associated with fewer relapses within 2 months, and decreased expression of interleukin 13 (IL-13) and increased expression of I-309 (CCL1) were associated with less relapses within 12 months. Differences in cytokine response from PBMCs were observed between RV- and RSV-induced first severe wheezing episode. Our findings also reveal new biomarkers for short- and medium-term prognosis in first-time wheezing children infected with RV or RSV.

Human Rhinoviruses in Pediatric Patients in a Tertiary Care Hospital in Germany: Molecular Epidemiology and Clinical Significance

Rhinoviruses (RVs) constitute a substantial public health burden. To evaluate their abundance and genetic diversity in pediatric patients, RV RNA in respiratory samples was assessed using real-time RT-PCR and partial nucleic acid sequencing of viral genomes. Additionally, clinical data were retrieved from patient charts to determine the clinical significance of pediatric RV infections. In total, the respiratory specimens of 776 patients (<18 years), collected from 2013 to 2017, were analyzed. Infections occurred throughout the entire year, with peaks occurring in fall and winter, and showed remarkably high intra- and interseasonal diversity for RV genotypes. RV species were detected in the following frequencies: 49.1% RV-A, 5.9% RV-B, and 43.6% RV-C. RV-C was found to be more frequently associated with asthma (p = 0.04) and bronchiolitis (p < 0.001), while RV-A was more frequently associated with fever (p = 0.001) and pneumonia (p = 0.002). Additionally, 35.3% of the patients had co-infections with other pathogens, which were associated with a longer hospital stay (p < 0.001), need for ventilation (p < 0.001), and pneumonia (p < 0.001). Taken together, this study shows pronounced RV genetic diversity in pediatric patients and indicates differences in RV-associated pathologies, as well as an important role for co-infections.

Innate Immune Responses by Respiratory Viruses, Including Rhinovirus, During Asthma Exacerbation

Viral infection, especially with rhinovirus (RV), is a major cause of asthma exacerbation. The production of anti-viral cytokines such as interferon (IFN)-β and IFN-α from epithelial cells or dendritic cells is lower in patients with asthma or those with high IgE, which can contribute to viral-induced exacerbated disease in these patients. As for virus-related factors, RV species C (RV-C) induces more exacerbated disease than other RVs, including RV-B. Neutrophils activated by viral infection can induce eosinophilic airway inflammation through different mechanisms. Furthermore, virus-induced or virus-related proteins can directly activate eosinophils. For example, CXCL10, which is upregulated during viral infection, activates eosinophils in vitro. The role of innate immune responses, especially type-2 innate lymphoid cells (ILC2) and epithelial cell-related cytokines including IL-33, IL-25, and thymic stromal lymphopoietin (TSLP), in the development of viral-induced airway inflammation has recently been established. For example, RV infection induces the expression of IL-33 or IL-25, or increases the ratio of ILC2 in the asthmatic airway, which is correlated with the severity of exacerbation. A mouse model has further demonstrated that virus-induced mucous metaplasia and ILC2 expansion are suppressed by antagonizing or deleting IL-33, IL-25, or TSLP. For treatment, IFNs including IFN-β suppress not only viral replication but also ILC2 activation in vitro. Agonists of toll-like receptor (TLR) 3 or 7 can induce IFNs, which can then suppress viral replication and ILC2 activation. Therefore, if delivered in the airway, IFNs or TLR agonists could become innovative treatments for virus-induced asthma exacerbation.

Comparison of immune response to human rhinovirus C and respiratory syncytial virus in highly differentiated human airway epithelial cells

Background

Human rhinovirus C (HRV-C) accounts for a large proportion of HRV-related illnesses, but the immune response to HRV-C infection has not been elucidated. Our objective was to assess the effect of HRV-C on cytokine secretion in human bronchial epithelial (HBE) cells grown at air–liquid interface (ALI) and compare it with that of respiratory syncytial virus (RSV).

Methods

HBE cells were differentiated at ALI culture and the full-length cDNA clones of HRV-C651 and HRV-C15, clinical isolates of HRV-C79 and HRV-C101, and two RSV isolates were inoculated in the HBE cells. The effect of HRV-C on cytokine secretion was assessed and compared with that of RSV.

Results

HRV-Cs infect and propagate in fully differentiated HBE cells and significantly increase the secretion of IFN-λ1, CCL5, IP10, IL-6, IL-8, and MCP-1. The virus loads positively correlated with the levels of the cytokines. HRV-C induced lower secretion of CCL5 (P = 0.048), IL-6 (P = 0.016), MCP-1 (P = 0.008), and IL-8 (P = 0.032), and similar secretion of IP10 (P = 0.214) and IFN-λ1 (P = 0.214) when compared with RSV.

Conclusion

HBE ALI culture system supported HRV-C infection and propagation and HRV-C induced relatively weaker cytokine expression than RSV.

Rhinovirus-Induced Cytokine Alterations With Potential Implications in Asthma Exacerbations: A Systematic Review and Meta-Analysis

Background

Rhinovirus (RV) infections are a major cause of asthma exacerbations. Unlike other respiratory viruses, RV causes minimal cytotoxic effects on airway epithelial cells and cytokines play a critical role in its pathogenesis. However, previous findings on RV-induced cytokine responses were largely inconsistent. Thus, this study sought to identify the cytokine/chemokine profiles induced by RV infection and their correlations with airway inflammatory responses and/or respiratory symptoms using systematic review, and to determine whether a quantitative difference exists in cytokine levels between asthmatic and healthy individuals via meta-analysis.

Methods

Relevant articles were obtained from PubMed, Scopus, and ScienceDirect databases. Studies that compared RV-induced cytokine responses between asthmatic and healthy individuals were included in the systematic review, and their findings were categorized based on the study designs, which were ex vivo primary bronchial epithelial cells (PBECs), ex vivo peripheral blood mononuclear cells (PBMCs), and human experimental studies. Data on cytokine levels were also extracted and analyzed using Review Manager 5.4.

Results

Thirty-four articles were included in the systematic review, with 18 of these further subjected to meta-analysis. Several studies reported the correlations between the levels of cytokines, such as IL-8, IL-4, IL-5, and IL-13, and respiratory symptoms. Evidence suggests that IL-25 and IL-33 may be the cytokines that promote type 2 inflammation in asthmatics after RV infection. Besides that, a meta-analysis revealed that PBECs from children with atopic asthma produced significantly lower levels of IFN-β [Effect size (ES): -0.84, p = 0.030] and IFN-λ (ES: -1.00, p = 0.002), and PBECs from adult atopic asthmatics produced significantly lower levels of IFN-β (ES: -0.68, p = 0.009), compared to healthy subjects after RV infection. A trend towards a deficient production of IFN-γ (ES: -0.56, p = 0.060) in PBMCs from adult atopic asthmatics was observed. In lower airways, asthmatics also had significantly lower baseline IL-15 (ES: -0.69, p = 0.020) levels.

Conclusion

Overall, RV-induced asthma exacerbations are potentially caused by an imbalance between Th1 and Th2 cytokines, which may be contributed by defective innate immune responses at cellular levels. Exogenous IFNs delivery may be beneficial as a prophylactic approach for RV-induced asthma exacerbations.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=184119, identifier CRD42020184119.

Rhinovirus Infections and Their Roles in Asthma: Etiology and Exacerbations

Rhinovirus infections can cause wheezing illnesses in all age groups. In preschool children, rhinovirus infections frequently initiate acute wheezing illnesses. Children who wheeze with rhinoviruses are at increased risk to go on to develop asthma. Once asthma is established, rhinovirus infections are potent triggers for acute airway obstruction and exacerbations in children and adults. Paradoxically, for most individuals, rhinovirus infections commonly cause cold symptoms with little or no involvement of the lower airways. This paradox has led investigators to identify specific risk factors and mechanisms for rhinovirus wheezing, and this review will outline progress in 3 main areas. First, the 3 species of rhinoviruses have different patterns of infection and virulence. Second, personal factors such as lung function and immunity influence lower respiratory outcomes of rhinovirus infection. The mucosal immune response is critical, and the quality of the interferon response and allergic inflammation interacts to determine the risk for rhinovirus wheezing. Finally, rhinovirus infections can promote pathogen-dominated airway microbiota that increase the risk for wheezing. Although specific antivirals for rhinovirus are still not available, identifying risk factors for wheezing illnesses has provided several other potential targets and strategies for reducing the risk of rhinovirus-induced wheezing and exacerbations of asthma.

Asthma as a risk factor for The progression of COVID-19

Background: Asthma is one of the most common chronic respiratory diseases in the world, standing for the most frequent cause for hospitalization and emergency cases. Respiratory viruses are the most triggering cause. Aim: To assess the role of viral infections, especially COVID-19, in the pathogenesis of asthma initiation and exacerbations. Method: Electronic search was done for the manuscripts focusing on asthma as a risk factor for complications after COVID-19 infection. The outcomes were titles, materials, methods and classified studies related or not related to the review study. Three hundred publications were identified and only ten studies were selected for analysis. Seven studies were review, one retrospective, one longitudinal cohort study and one letter to the editor. Results: The included literature sources have highlighted different effect of asthma on COVID-19 progression. Asthma can be triggered by this virus and asthmatic patients with COVID-19 should not stop their treatment. Others suggest that asthma does not appear to be a significant risk factor for developing severe COVID-19 requiring hospitalization or intubation. Conclusions: Asthma is considered as comorbidity factor leading to complications and mortality in subjects infected with COVID-19.

Personal Network Inference Unveils Heterogeneous Immune Response Patterns to Viral Infection in Children with Acute Wheezing

Human rhinovirus (RV)-induced exacerbations of asthma and wheeze are a major cause of emergency room presentations and hospital admissions among children. Previous studies have shown that immune response patterns during these exacerbations are heterogeneous and are characterized by the presence or absence of robust interferon responses. Molecular phenotypes of asthma are usually identified by cluster analysis of gene expression levels. This approach however is limited, since genes do not exist in isolation, but rather work together in networks. Here, we employed personal network inference to characterize exacerbation response patterns and unveil molecular phenotypes based on variations in network structure. We found that personal gene network patterns were dominated by two major network structures, consisting of interferon-response versus FCER1G-associated networks. Cluster analysis of these structures divided children into subgroups, differing in the prevalence of atopy but not RV species. These network structures were also observed in an independent cohort of children with virus-induced asthma exacerbations sampled over a time course, where we showed that the FCER1G-associated networks were mainly observed at late time points (days four-six) during the acute illness. The ratio of interferon- and FCER1G-associated gene network responses was able to predict recurrence, with low interferon being associated with increased risk of readmission. These findings demonstrate the applicability of personal network inference for biomarker discovery and therapeutic target identification in the context of acute asthma which focuses on variations in network structure.

The proton ATPase inhibitor bafilomycin A1 reduces the release of rhinovirus C and cytokines from primary cultures of human nasal epithelial cells

Rhinovirus species C (RV-C) causes more severe asthma attacks than other rhinovirus species. However, the modulation of RV-C replication by drugs has not been well studied. Primary human nasal epithelial (HNE) cells cultured on filter membranes with air-liquid interface methods were infected with RV-C03, and the levels of RV-C03 RNA collected from the airway surface liquid (ASL) of HNE cells were measured with a SYBR Green assay. Pretreatment of HNE cells with the specific vacuolar H⁺-ATPase inhibitor bafilomycin A₁ reduced the RV-C03 RNA levels in the ASL; inflammatory cytokines, including interleukin (IL)-1β, IL-6 and IL-8, in the supernatant; the mRNA expression of the RV-C receptor cadherin-related family member 3 (CDHR3) in the cells; and the number of acidic endosomes where RV-B RNA enters the cytoplasm. The levels of RV-C03 RNA in the ASL obtained from HNE cells with the CDHR3 rs6967,330 G/A genotype tended to be higher than those obtained from HNE cells with the G/G genotype. Pretreatment with the Na⁺/H⁺ exchanger inhibitor ethyl-isopropyl amiloride or either of the macrolides clarithromycin or EM900 also reduced RV-C03 RNA levels in the ASL and the number of acidic endosomes in HNE cells. In addition, significant levels of RV-A16, RV-B14 and RV-C25 RNA were detected in the ASL, and bafilomycin A₁ also decreased the RV-C25 RNA levels. These findings suggest that bafilomycin A₁ may reduce the release of RV-Cs and inflammatory cytokines from human airway epithelial cells. RV-Cs may be sensitive to drugs, including bafilomycin A₁, that increase endosomal pH, and CDHR3 may mediate virus entry through receptor-mediated endocytosis in human airway epithelial cells.

Human Rhinoviruses in Adult Patients in a Tertiary Care Hospital in Germany: Molecular Epidemiology and Clinical Significance

Rhinoviruses (RVs) constitute a substantial public health burden. To evaluate their abundance and genetic diversity in adult patients, RV RNA in respiratory samples was assessed using real-time RT-PCR and the partial nucleic acid sequencing of viral genomes. Additionally, clinical data were retrieved from patient charts to determine the clinical significance of adult RV infections. In total, the respiratory specimens of 284 adult patients (18-90 years), collected from 2013 to 2017, were analyzed. Infections occurred throughout the entire year, with peaks occurring in fall and winter, and showed a remarkably high intra- and interseasonal diversity of RV genotypes. RV species were detected in the following ratios: 60.9% RV-A 173, 12.7% RV-B, and 26.4% RV-C. No correlations between RV species and underlying comorbidities such as asthma (p = 0.167), COPD (p = 0.312) or immunosuppression (p = 0.824) were found. However, 21.1% of the patients had co-infections with other pathogens, which were associated with a longer hospital stay (p = 0.024), LRTI (p < 0.001), and pneumonia (p = 0.01). Taken together, this study shows a pronounced genetic diversity of RV in adults and underlines the important role of co-infections. No correlation of specific RV species with a particular clinical presentation could be deduced.

In Vitro Modelling of Respiratory Virus Infections in Human Airway Epithelial Cells - A Systematic Review

Respiratory tract infections (RTI) are a major cause of morbidity and mortality in humans. A large number of RTIs is caused by viruses, often resulting in more severe disease in infants, elderly and the immunocompromised. Upon viral infection, most individuals experience common cold-like symptoms associated with an upper RTI. However, in some cases a severe and sometimes life-threatening lower RTI may develop. Reproducible and scalable in vitro culture models that accurately reflect the human respiratory tract are needed to study interactions between respiratory viruses and the host, and to test novel therapeutic interventions. Multiple in vitro respiratory cell culture systems have been described, but the majority of these are based on immortalized cell lines. Although useful for studying certain aspects of viral infections, such monomorphic, unicellular systems fall short in creating an understanding of the processes that occur at an integrated tissue level. Novel in vitro models involving primary human airway epithelial cells and, more recently, human airway organoids, are now in use. In this review, we describe the evolution of in vitro cell culture systems and their characteristics in the context of viral RTIs, starting from advances after immortalized cell cultures to more recently developed organoid systems. Furthermore, we describe how these models are used in studying virus-host interactions, e.g. tropism and receptor studies as well as interactions with the innate immune system. Finally, we provide an outlook for future developments in this field, including co-factors that mimic the microenvironment in the respiratory tract.

Diesel exposure increases susceptibility of primary human nasal epithelial cells to rhinovirus infection

Nasal epithelial cells (NECs) are among the first cells to be exposed to air pollutants and respiratory viruses. Although it is known that air pollution exposure and rhinovirus infections increase the risk for asthma development independently, it is unclear how these risk factors interact on a cellular level. Therefore, we aimed to investigate how exposure to diesel particulate matter (DPM) modifies the response of primary NECs to rhinovirus (RV) infection in vitro. Exposure of re-differentiated, primary NECs (49 healthy children [0-7 years], 12 adults) to DPM modified the mRNA expression of viral cell-surface receptors, pattern recognition receptors, and pro-inflammatory response (also protein levels). After exposure to DPM, we additionally infected the NECs with RV-1b and RV-16. Viral loads (assessed by titration assays) were significantly higher in DPM-exposed compared with non-exposed NECs. Exposure to DPM prior to RV infection resulted in a significant upregulation of pro-inflammatory cytokines (mRNA and protein level) and β-defensins mRNA, and significant downregulation of pattern recognition receptors mRNA and CXCL10 (mRNA and protein levels). There was no difference between all outcomes of NECs from children and adults. We can conclude that exposure to DPM prior to RV infection increases viral loads by downregulation of viral defense receptors and upregulation of pro-inflammatory cytokines. Our findings indicate a strong interaction between air pollution and the antiviral response to RV infection in NECs. We provide mechanistic evidence that exposure to air pollution increases susceptibility to RV infection.

Dual role of the miR-146 family in rhinovirus-induced airway inflammation and allergic asthma exacerbation

Rhinovirus (RV) infections are associated with asthma exacerbations. MicroRNA-146a and microRNA-146b (miR-146a/b) are anti-inflammatory miRNAs that suppress signaling through the nuclear factor kappa B (NF-κB) pathway and inhibit pro-inflammatory chemokine production in primary human bronchial epithelial cells (HBECs). In the current study, we aimed to explore whether miR-146a/b could regulate cellular responses to RVs in HBECs and airways during RV-induced asthma exacerbation. We demonstrated that expression of miR-146a/b and pro-inflammatory chemokines was increased in HBECs and mouse airways during RV infection. However, transfection with cell-penetrating peptide (CPP)-miR-146a nanocomplexes before infection with RV significantly reduced the expression of the pro-inflammatory chemokines CCL5, IL-8 and CXCL1, increased interferon-λ production, and attenuated infection with the green fluorescent protein (GFP)-expressing RV-A16 in HBECs. Concordantly, compared to wild-type (wt) mice, Mir146a/b-/- mice exhibited more severe airway neutrophilia and increased T helper (Th)1 and Th17 cell infiltration in response to RV-A1b infection and a stronger Th17 response with a less prominent Th2 response in house dust mite extract (HDM)-induced allergic airway inflammation and RV-induced exacerbation models. Interestingly, intranasal administration of CPP-miR-146a nanocomplexes reduced HDM-induced allergic airway inflammation without a significant effect on the Th2/Th1/Th17 balance in wild-type mice. In conclusion, the overexpression of miR-146a has a strong anti-inflammatory effect on RV infection in HBECs and a mouse model of allergic airway inflammation, while a lack of miR-146a/b leads to attenuated type 2 cell responses in mouse models of allergic airway inflammation and RV-induced exacerbation of allergic airway inflammation. Furthermore, our data indicate that the application of CPP-miR-146a nanocomplexes has therapeutic potential for targeting airway inflammation.

Enhanced Neutralizing Antibody Responses to Rhinovirus C and Age-Dependent Patterns of Infection

Rationale: Rhinovirus (RV) C can cause asymptomatic infection and respiratory illnesses ranging from the common cold to severe wheezing.Objectives: To identify how age and other individual-level factors are associated with susceptibility to RV-C illnesses.Methods: Longitudinal data from the COAST (Childhood Origins of Asthma) birth cohort study were analyzed to determine relationships between age and RV-C infections. Neutralizing antibodies specific for RV-A and RV-C (three types each) were determined using a novel PCR-based assay. Data were pooled from 14 study cohorts in the United States, Finland, and Australia, and mixed-effects logistic regression was used to identify factors related to the proportion of RV-C versus RV-A detection.Measurements and Main Results: In COAST, RV-A and RV-C infections were similarly common in infancy, whereas RV-C was detected much less often than RV-A during both respiratory illnesses and scheduled surveillance visits (P < 0.001, χ2) in older children. The prevalence of neutralizing antibodies to RV-A or RV-C types was low (5-27%) at the age of 2 years, but by the age of 16 years, RV-C seropositivity was more prevalent (78% vs. 18% for RV-A; P < 0.0001). In the pooled analysis, the RV-C to RV-A detection ratio during illnesses was significantly related to age (P < 0.0001), CDHR3 genotype (P < 0.05), and wheezing illnesses (P < 0.05). Furthermore, certain RV types (e.g., C2, C11, A78, and A12) were consistently more virulent and prevalent over time.Conclusions: Knowledge of prevalent RV types, antibody responses, and populations at risk based on age and genetics may guide the development of vaccines or other novel therapies against this important respiratory pathogen.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Increased antiviral response in circulating lymphocytes from hypogammaglobulinemia patients

BACKGROUND

B cells play a crucial role during rhinovirus (RV) infections by production of virus-neutralizing antibodies. A main feature of common variable immunodeficiency (CVID) is hypogammaglobulinemia (HG). HG patients have severely reduced levels of antibody-producing B cells and suffer from prolonged virus infections. Here, we addressed whether antiviral response of peripheral blood lymphocytes differs between HG patients and healthy individuals during natural RV infection.

METHODS

Using fluorescence-activated cell sorting, B-cell subsets were analyzed. Simultaneously, CD19 + B cells, CD14 + monocytes, and CD3 + T cells were sorted from frozen peripheral blood mononuclear cells from 11 RV-infected hypogammaglobulinemia patients, 7 RV-infected control subjects, and 14 noninfected control subjects. Real-time PCR was used to study expression of antiviral genes. A pan-RV PCR was used to detect RV genome in all samples.

RESULTS

In HG patients, total B-cell numbers, as well as IgA + and IgG + switched memory B cells, were reduced while naïve B cells and T cells were increased. STAT1 expression was increased in HG patients compared to controls in all lymphocyte subsets analyzed. The expression of antiviral genes IFITM1 and MX1 correlated with STAT1 expression in B cells and monocytes. RV RNA was found in 88.9% of monocytes from infected HG patients, 85.7% of monocytes from infected controls, and 7.1% of monocytes from uninfected controls.

CONCLUSIONS

We demonstrate an increased antiviral response in B cells and monocytes in HG patients and their correlation with STAT1 expression. Monocytes of infected HG patients and infected non-HG controls carry RV RNA.

Rhinovirus-Induced Modulation of Epithelial Phenotype: Role in Asthma

Human rhinoviruses have been linked both to the susceptibility of asthma development and to the triggering of acute exacerbations. Given that the human airway epithelial cell is the primary site of human rhinovirus (HRV) infection and replication, the current review focuses on how HRV-induced modulation of several aspects of epithelial cell phenotype could contribute to the development of asthma or to the induction of exacerbations. Modification of epithelial proinflammatory and antiviral responses are considered, as are alterations in an epithelial barrier function and cell phenotype. The contributions of the epithelium to airway remodeling and to the potential modulation of immune responses are also considered. The potential interactions of each type of HRV-induced epithelial phenotypic changes with allergic sensitization and allergic phenotype are also considered in the context of asthma development and of acute exacerbations.

Orosomucoid-like 3 Supports Rhinovirus Replication in Human Epithelial Cells

Polymorphism at the 17q21 gene locus and wheezing responses to rhinovirus (RV) early in childhood conspire to increase the risk of developing asthma. However, the mechanisms mediating this gene-environment interaction remain unclear. In this study, we investigated the impact of one of the 17q21-encoded genes, ORMDL3 (orosomucoid-like 3), on RV replication in human epithelial cells. ORMDL3 knockdown inhibited RV-A16 replication in HeLa, BEAS-2B, A549, and NCI-H358 epithelial cell lines and primary nasal and bronchial epithelial cells. Inhibition varied by RV species, as both minor and major group RV-A subtypes RV-B52 and RV-C2 were inhibited but not RV-C15 or RV-C41. ORMDL3 siRNA did not affect expression of the major group RV-A receptor ICAM-1 or initial internalization of RV-A16. The two major outcomes of ORMDL3 activity, SPT (serine palmitoyl-CoA transferase) inhibition and endoplasmic reticulum (ER) stress induction, were further examined: silencing ORMDL3 decreased RV-induced ER stress and IFN-β mRNA expression. However, pharmacologic induction of ER stress and concomitant increased IFN-β inhibited RV-A16 replication. Conversely, blockade of ER stress with tauroursodeoxycholic acid augmented replication, pointing to an alternative mechanism for the effect of ORMDL3 knockdown on RV replication. In comparison, the SPT inhibitor myriocin increased RV-A16 but not RV-C15 replication and negated the inhibitory effect of ORMDL3 knockdown. Furthermore, lipidomics analysis revealed opposing regulation of specific sphingolipid species (downstream of SPT) by myriocin and ORMDL3 siRNA, correlating with the effect of these treatments on RV replication. Together, these data revealed a requirement for ORMDL3 in supporting RV replication in epithelial cells via SPT inhibition.

Molecular epidemiology and clinical impact of rhinovirus infections in adults during three epidemic seasons in 11 European countries (2007-2010)

Background

Differences in clinical impact between rhinovirus (RVs) species and types in adults are not well established. The objective of this study was to determine the epidemiology and clinical impact of the different RV species.

Methods

We conducted a prospective study of RVs infections in adults with acute cough/lower respiratory tract infection (LRTI) and asymptomatic controls. Subjects were recruited from 16 primary care networks located in 11 European countries between 2007 and 2010. RV detection and genotyping was performed by means of real time and conventional reverse-transcriptase polymerase chain reaction assays, followed by sequence analysis. Clinical data were obtained from medical records and patient symptom diaries.

Results

RVs were detected in 566 (19%) of 3016 symptomatic adults, 102 (4%) of their 2539 follow-up samples and 67 (4%) of 1677 asymptomatic controls. Genotyping was successful for 538 (95%) symptomatic subjects, 86 (84%) follow-up infections and 62 (93%) controls. RV-A was the prevailing species, associated with an increased risk of LRTI as compared with RV-B (relative risk (RR), 4.5; 95% CI 2.5 to 7.9; p<0.001) and RV-C (RR 2.2; 95% CI 1.2 to 3.9; p=0.010). In symptomatic subjects, RV-A loads were higher than those of RV-B (p=0.015). Symptom scores and duration were similar across species. More RV-A infected patients felt generally unwell in comparison to RV-C (p=0·023). Of the 140 RV types identified, five were new types; asymptomatic infections were associated with multiple types.

Interpretation

In adults, RV-A is significantly more often detected in cases with acute cough/LRTI than RV-C, while RV-B infection is often found in asymptomatic patients.

Childhood asthma heterogeneity at the era of precision medicine: Modulating the immune response or the microbiota for the management of asthma attack

Exacerbations are a main characteristic of asthma. In childhood, the risk is increasing with severity. Exacerbations are a strong phenotypic marker, particularly of severe and therapy-resistant asthma. These early-life events may influence the evolution and be involved in lung function decline.

In children, asthma attacks are facilitated by exposure to allergens and pollutants, but are mainly triggered by microbial agents. Multiple studies have assessed immune responses to viruses, and to a lesser extend bacteria, during asthma exacerbation. Research has identified impairment of innate immune responses in children, related to altered pathogen recognition, interferon release, or anti-viral response. Influence of this host-microbiota dialog on the adaptive immune response may be crucial, leading to the development of biased T helper (Th)2 inflammation. These dynamic interactions may impact the presentations of asthma attacks, and have long-term consequences.

The aim of this review is to synthesize studies exploring immune mechanisms impairment against viruses and bacteria promoting asthma attacks in children. The potential influence of the nature of infectious agents and/or preexisting microbiota on the development of exacerbation is also addressed. We then discuss our understanding of how these diverse host-microbiota interactions in children may account for the heterogeneity of endotypes and clinical presentations. Finally, improving the knowledge of the pathophysiological processes induced by infections has led to offer new opportunities for the development of preventive or curative therapeutics for acute asthma. A better definition of asthma endotypes associated with precision medicine might lead to substantial progress in the management of severe childhood asthma.

CDHR3 Asthma-Risk Genotype Affects Susceptibility of Airway Epithelium to Rhinovirus C Infections

CDHR3 (cadherin-related family member 3) is a transmembrane protein that is highly expressed in airway epithelia and the only known receptor for rhinovirus C (RV-C). A CDHR3 SNP (rs6967330) with G to A base change has been linked to severe exacerbations of asthma and increased susceptibility to RV-C infections in young children. The goals of this study were to determine the subcellular localization of CDHR3 and to test the hypothesis that CDHR3 asthma-risk genotype affects epithelial cell function and susceptibility to RV-C infections of the airway epithelia. We used immunofluorescence imaging, Western blot analysis, and transmission electron microscopy to show CDHR3 subcellular localization in apical cells, including expression in the cilia of airway epithelia. Polymorphisms in CDHR3 rs6967330 locus (G→A) that were previously associated with childhood asthma were related to differences in CDHR3 expression and epithelial cell function. The rs6967330 A allele was associated with higher overall protein expression and RV-C binding and replication compared with the rs6967330 G allele. Furthermore, the rs6967330 A allele was associated with earlier ciliogenesis and higher FOXJ1 expression. Finally, CDHR3 genotype had no significant effects on membrane integrity or ciliary beat function. These findings provide information on the subcellular localization and possible functions of CDHR3 in the airways and link CDHR3 asthma-risk genotype to increased RV-C binding and replication.

Evolving concepts in how viruses impact asthma: A Work Group Report of the Microbes in Allergy Committee of the American Academy of Allergy, Asthma & Immunology

Over the past decade, there have been substantial advances in our understanding about how viral infections regulate asthma. Important lessons have been learned from birth cohort studies examining viral infections and subsequent asthma and from understanding the relationships between host genetics and viral infections, the contributions of respiratory viral infections to patterns of immune development, the impact of environmental exposure on the severity of viral infections, and how the viral genome influences host immune responses to viral infections. Further, there has been major progress in our knowledge about how bacteria regulate host immune responses in asthma pathogenesis. In this article, we also examine the dynamics of bacterial colonization of the respiratory tract during viral upper respiratory tract infection, in addition to the relationship of the gut and respiratory microbiomes with respiratory viral infections. Finally, we focus on potential interventions that could decrease virus-induced wheezing and asthma. There are emerging therapeutic options to decrease the severity of wheezing exacerbations caused by respiratory viral infections. Primary prevention is a major goal, and a strategy toward this end is considered.

Mechanisms of eosinophilic inflammation

Eosinophils play roles in the pathogenesis of various diseases. In order to accumulate within sites of inflammation, eosinophils must adhere to, and migrate across the microvasculature. These processes are largely controlled by type 2-immune responses; interleukin (IL)-4 and IL-13 induce the expression of endothelial adhesion molecule vascular cell adhesion molecule-1 (VCAM-1), a representative adhesive ligand for eosinophils, while also stimulating generations of CC chemokines from structural cells, including epithelial cells. VCAM-1 and CC chemokines synergistically induce transmigration of eosinophils to the tissue inflammation site. Another type 2 cytokine, IL-5, prolongs survival, and enhances the effector functions of eosinophils. Recently, accumulating evidence has established that corticosteroid-resistant group 2 innate lymphoid cells are cellular sources for IL-5. Another immunological mechanism that may be contributing to eosinophilic inflammation involves type 1 immune system-associated molecules such as interferons and IP-10. In addition to these immune pathways, lipid mediators, such as cysteinyl leukotrienes, directly provoke the infiltration and activation of eosinophils. Extracellular matrix proteins including periostin also induce the adhesion and activation of eosinophils. Finally, activated neutrophils can also induce eosinophil transmigration. In summary, various mechanisms are involved within eosinophilic inflammation, and effective therapeutic strategies targeting these pathways should be established.

Rhinovirus Infection Is Associated With Airway Epithelial Cell Necrosis and Inflammation via Interleukin-1 in Young Children With Cystic Fibrosis

Introduction: The responses of cystic fibrosis (CF) airway epithelial cells (AEC) to rhinovirus (RV) infection are likely to contribute to early pathobiology of lung disease with increased neutrophilic inflammation and lower apoptosis reported. Necrosis of AEC resulting in airway inflammation driven by IL-1 signaling is a characteristic finding in CF detectable in airways of young children. Being the most common early-life infection, RV-induced epithelial necrosis may contribute to early neutrophilic inflammation in CF via IL-1 signaling. As little is known about IL-1 and biology of CF lung disease, this study assessed cellular and pro-inflammatory responses of CF and non-CF AEC following RV infection, with the hypothesis that RV infection drives epithelial necrosis and IL-1 driven inflammation. Methods:Primary AEC obtained from children with (n = 6) and without CF (n = 6) were infected with RV (MOI 3) for 24 h and viable, necrotic and apoptotic events quantified via flow cytometry using a seven-step gating strategy (% total events). IL-1α, IL-1β, IL-1Ra, IL-8, CXCL10, CCL5, IFN-β, IL-28A, IL-28B, and IL-29 were also measured in cell culture supernatants (pg/mL). Results:RV infection reduced viable events in non-CF AEC (p < 0.05), increased necrotic events in non-CF and CF AEC (p < 0.05) and increased apoptotic events in non-CF AEC (p < 0.05). Infection induced IL-1α and IL-1β production in both phenotypes (p < 0.05) but only correlated with necrosis (IL-1α: r = 0.80; IL-1β: r = 0.77; p < 0.0001) in CF AEC. RV infection also increased IL-1Ra in non-CF and CF AEC (p < 0.05), although significantly more in non-CF AEC (p < 0.05). Finally, infection stimulated IL-8 production in non-CF and CF AEC (p < 0.05) and correlated with IL-1α (r = 0.63 & r = 0.74 respectively; p < 0.0001). Conclusions:This study found RV infection drives necrotic cell death in CF AEC. Furthermore, RV induced IL-1 strongly correlated with necrotic cell death in these cells. As IL-1R signaling drives airway neutrophilia and mucin production, these observations suggest RV infection early in life may exacerbate inflammation and mucin accumulation driving early CF lung disease. Since IL-1R can be targeted therapeutically with IL-1Ra, these data suggest a new anti-inflammatory therapeutic approach targeting downstream effects of IL-1R signaling to mitigate viral-induced, muco-inflammatory triggers of early lung disease.

Rhinovirus C15 Induces Airway Hyperresponsiveness via Calcium Mobilization in Airway Smooth Muscle

Rhinovirus (RV) exposure evokes exacerbations of asthma that markedly impact morbidity and mortality worldwide. The mechanisms by which RV induces airway hyperresponsiveness (AHR) or by which specific RV serotypes differentially evoke AHR remain unknown. We posit that RV infection evokes AHR and inflammatory mediator release, which correlate with degrees of RV infection. Furthermore, we posit that rhinovirus C-induced AHR requires paracrine or autocrine mediator release from epithelium that modulates agonist-induced calcium mobilization in human airway smooth muscle. In these studies, we used an ex vivo model to measure bronchoconstriction and mediator release from infected airways in human precision cut lung slices to understand how RV exposure alters airway constriction. We found that rhinovirus C15 (RV-C15) infection augmented carbachol-induced airway narrowing and significantly increased release of IP-10 (IFN-γ-induced protein 10) and MIP-1β (macrophage inflammatory protein-1β) but not IL-6. RV-C15 infection of human airway epithelial cells augmented agonist-induced intracellular calcium flux and phosphorylation of myosin light chain in co-cultured human airway smooth muscle to carbachol, but not after histamine stimulation. Our data suggest that RV-C15-induced structural cell inflammatory responses are associated with viral load but that inflammatory responses and alterations in agonist-mediated constriction of human small airways are uncoupled from viral load of the tissue.

Development of a Rhinovirus Inoculum Using a Reverse Genetics Approach

Background

Experimental inoculation is an important tool for common cold and asthma research. Producing rhinovirus (RV) inocula from nasal secretions has required prolonged observation of the virus donor to exclude extraneous pathogens. We produced a RV-A16 inoculum using reverse genetics and determined the dose necessary to cause moderate colds in seronegative volunteers.

Methods

The consensus sequence of RV-A16 from a previous inoculum was cloned, and inoculum virus was produced using reverse genetics techniques. After safety testing, volunteers were inoculated with either RV-A16 (n = 26) or placebo (n = 10), Jackson cold scores were recorded, and nasal secretions were tested for shedding of RV-A16 ribonucleic acid.

Results

The reverse genetics process produced infectious virus that was neutralized by specific antisera and had a mutation rate similar to conventional virus growth techniques. The 1000 median tissue culture infectious dose (TCID₅₀) dose produced moderate colds in most individuals with effects similar to that of a previously tested conventional RV-A16 inoculum.

Conclusions

Reverse genetics techniques produced a RV-A16 inoculum that can cause clinical colds in seronegative volunteers, and they also serve as a stable source of virus for laboratory use. The recombinant production procedures eliminate the need to derive seed virus from nasal secretions, thus precluding introduction of extraneous pathogens through this route.

Role of viruses in asthma

Respiratory viral infections are the most important triggers of asthma exacerbations. Rhinovirus (RV), the common cold virus, is clearly the most prevalent pathogen constantly circulating in the community. This virus also stands out from other viral factors due to its large diversity (about 170 genotypes), very effective replication, a tendency to create Th2-biased inflammatory environment and association with specific risk genes in people predisposed to asthma development (CDHR3). Decreased interferon responses, disrupted airway epithelial barrier, environmental exposures (including biased airway microbiome), and nutritional deficiencies (low in vitamin D and fish oil) increase risk to RV and other virus infections. It is intensively debated whether viral illnesses actually cause asthma. Respiratory syncytial virus (RSV) is the leading causative agent of bronchiolitis, whereas RV starts to dominate after 1 year of age. Breathing difficulty induced by either of these viruses is associated with later asthma, but the risk is higher for those who suffer from severe RV-induced wheezing. The asthma development associated with these viruses has unique mechanisms, but in general, RV is a risk factor for later atopic asthma, whereas RSV is more likely associated with later non-atopic asthma. Treatments that inhibit inflammation (corticosteroids, omalizumab) effectively decrease RV-induced wheezing and asthma exacerbations. The anti-RSV monoclonal antibody, palivizumab, decreases the risk of severe RSV illness and subsequent recurrent wheeze. A better understanding of personal and environmental risk factors and inflammatory mechanisms leading to asthma is crucial in developing new strategies for the prevention and treatment of asthma.

Rhinovirus species and tonsillar immune responses

Background

Rhinovirus A and C infections are important contributors to asthma induction and exacerbations. No data exist on the interaction of local immune responses in rhinovirus infection. Therefore, we aimed to determine the tonsillar immune responses according to rhinovirus A, B and C infections.

Methods

We collected tonsillar samples, nasopharyngeal aspirates and peripheral blood from 42 rhinovirus positive tonsillectomy patients. Fifteen respiratory viruses or their types were investigated from nasopharynx and tonsil tissue, and rhinovirus species were typed. The expression of 10 cytokines and 4 transcription factors (IFN-α, IFN-β, IFN-γ, IL-10, IL-13, IL-17, IL-28, IL-29, IL-37, TGF-β, FOXP3, GATA3, RORC2 and Tbet) were studied from tonsil tissue by quantitative PCR. A standard questionnaire of respiratory symptoms and health was filled by the patient or his/her guardian. The patients were divided into three groups by the determination of rhinovirus species.

Results

Overall, 16 patients had rhinovirus A, 12 rhinovirus B and 14 rhinovirus C infection. In rhinovirus B positive group there were significantly less men (P = 0.0072), less operated in spring (P = 0.0096) and more operated in fall (P = 0.030) than in rhinovirus A or C groups. Rhinovirus A positive patients had more respiratory symptoms (P = 0.0074) and particularly rhinitis (P = 0.036) on the operation day. There were no significant differences between the groups in virus codetection. In adjusted analysis, rhinovirus C infections were associated with increased IFN-α (P = 0.045) and decreased RORC2 expression (P = 0.025).

Conclusions

Rhinovirus species associated differently with clinical characteristics and tonsillar cytokine responses.

Asthma and viral infections: An intricate relationship

OBJECTIVE

To synthesize available data related to the complex associations among viral infections, atopy, and asthma.

DATA SOURCES

Key historical articles, articles highlighted in our recent review of most significant recent asthma advancements, and findings from several birth cohorts related to asthma and viral infections were reviewed. In addition, PubMed was searched for review articles and original research related to the associations between viral infection and asthma, using the search words asthma, viral infections, atopy, development of asthma, rhinovirus (RV), and respiratory syncytial virus (RSV).

STUDY SELECTIONS

Articles were selected based on novelty and relevance to our topic of interest, the role of asthma and viral infections, and possible mechanisms to explain the association.

RESULTS

There is a large body of evidence demonstrating a link between early viral infections (especially RV and RSV) and asthma inception and exacerbations. RV-induced wheezing is an important risk factor for asthma only when atopy is present, with much evidence supporting the idea that sensitization is a risk factor for early RV-induced wheezing, which in turn is a risk factor for asthma. RSV, on the other hand, is a more important risk factor for nonatopic asthma, with severe infections conferring greater risk.

CONCLUSION

There are important differences in the development of atopic and nonatopic asthma, with several proposed mechanisms explaining the association between viral infections and the development of asthma and asthma exacerbations. Understanding these complex associations is important for developing asthma prevention strategies and targeted asthma therapies.

Clinical and Th1/Th2 immune response features of hospitalized children with human rhinovirus infection

This study aimed to assess the clinical characteristics and T-helper 1 (Th1)/Th2 profile of human rhinovirus (HRV) infection in children with bronchiolitis and pneumonia, compared with the respiratory syncytial virus (RSV). In September 2013 to August 2014, 335 nasopharyngeal aspirates from children below 14 with bronchiolitis and pneumonia were screened for HRV and 13 other respiratory viruses by PCR or reverse transcription PCR. Interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-6, IL-10, and tumor necrosis factor (TNF)-α were detected by multiplex enzyme-linked immunosorbent assay. HRVs were found in 66 cases (19.7%), including 35 bronchiolitis and 31 pneumonia cases. Compared with the RSV alone group, children with pneumonia had more frequent wheezing episodes in HRV (P_a  = .001) and HRV + non-RSV (P_b  = .002) groups, and fever in the HRV (P_f  = .004) and HRV + RSV (P_g  = .005) groups. Among patients with bronchiolitis, cases with HRV alone were more likely to present in winter than those with RSV alone (P_i  = .010) and HRV + non-RSV (P_j  = .014), and less numerous in summer compared with HRV + non-RSV (P_h  = .005). Children with HRV alone were more susceptible to have a history of eczema than RSV alone among bronchiolitis (P_c  < .001) and pneumonia (P_e  = .033) cases. HRV bronchiolitis cases had increased IL-4/IFN-γ and decreased TNF-α/IL-10 ratios, compared with HRV pneumonia counterparts. HRV is a major non-RSV pathogen causing hospitalization in children with bronchiolitis and pneumonia and induces an imbalanced Th1/Th2 response in bronchiolitis. Compared with RSV infection, HRV bronchiolitis and pneumonia differ significantly regarding wheezing episodes, susceptibility to eczema, fever occurrence, and seasonal prevalence.

Molecular detection of respiratory pathogens and typing of human rhinovirus of adults hospitalized for exacerbation of asthma and chronic obstructive pulmonary disease

Background

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and asthma are associated with a variety of precipitating factors including infection. This study assessed the infective viral etiologies by real-time multiplex polymerase chain reaction of patients hospitalized with AECOPD and asthma exacerbations. In addition, infective etiologies were assessed for association with the clinical outcome of the patients.

Methods

Adults admitted with AECOPD and asthma exacerbations between August 2016 and July 2017 were recruited. Nasopharyngeal aspirate (NPA) samples were obtained from the patients within 1–2 days of admission and subjected to pathogen detection and human rhinovirus (HRV) typing.

Results

Altogether 402 patients with AECOPD, 80 stable COPD, 100 asthma exacerbation and 21 stable asthma subjects were recruited. Among those admitted for AECOPD and asthma exacerbations, 141(35.1%) and 45(45.0%) respectively had pathogens identified in the NPA specimens. The commonest virus identified was influenza A followed by HRV. HRV typing identified HRV-A and HRV-C as the more common HRV with a wide variety of genotypes. Identification of pathogens in NPA or HRV typing otherwise did not affect clinical outcomes including the hospital length of stay, readmission rates and mortality except that identification of pathogens in asthma exacerbation was associated with a lower rate of readmissions at 30 and 60 days.

Conclusions

Many respiratory viruses were associated with AECOPD and asthma exacerbation. HRV-A and HRV-C were the more common HRV associated with exacerbations. Identification of pathogens in NPA was associated with less readmissions for asthma patients at 30 and 60 days.

Trial registration

ClinicalTrials.gov NCT02866357.

Supplementary information

Supplementary information accompanies this paper at10.1186/s12931-019-1181-0.

MEK inhibition drives anti-viral defence in RV but not RSV challenged human airway epithelial cells through AKT/p70S6K/4E-BP1 signalling

BACKGROUND

The airway epithelium is a major target tissue in respiratory infections, and its antiviral response is mainly orchestrated by the interferon regulatory factor-3 (IRF3), which subsequently induces type I (β) and III (λ) interferon (IFN) signalling. Dual specificity mitogen-activated protein kinase kinase (MEK) pathway contributes to epithelial defence, but its role in the regulation of IFN response in human primary airway epithelial cells (AECs) is not fully understood. Here, we studied the impact of a small-molecule inhibitor (MEKi) on the IFN response following challenge with two major respiratory viruses rhinovirus (RV2) and respiratory syncytial virus (RSVA2) and a TLR3 agonist, poly(I:C).

METHODS

The impact of MEKi on viral load and IFN response was evaluated in primary AECs with or without a neutralising antibody against IFN-β. Quantification of viral load was determined by live virus assay and absolute quantification using qRT-PCR. Secretion of cytokines was determined by AlphaLISA/ELISA and expression of interferon-stimulated genes (ISGs) was examined by qRT-PCR and immunoblotting. A poly(I:C) model was also used to further understand the molecular mechanism by which MEK controls IFN response. AlphaLISA, siRNA-interference, immunoblotting, and confocal microscopy was used to investigate the effect of MEKi on IRF3 activation and signalling. The impact of MEKi on ERK and AKT signalling was evaluated by immunoblotting and AlphaLISA.

RESULTS

Here, we report that pharmacological inhibition of MEK pathway augments IRF3-driven type I and III IFN response in primary human AECs. MEKi induced activation of PI3K-AKT pathway, which was associated with phosphorylation/inactivation of the translational repressor 4E-BP1 and activation of the protein synthesis regulator p70 S6 kinase, two critical translational effectors. Elevated IFN-β response due to MEKi was also attributed to decreased STAT3 activation, which consequently dampened expression of the transcriptional repressor of IFNB1 gene, PRDI-BF1. Augmented IFN response translated into inhibition of rhinovirus 2 replication in primary AECs but not respiratory syncytial virus A2.

CONCLUSIONS

Our findings unveil MEK as a key molecular mechanism by which rhinovirus dampens the epithelial cell's antiviral response. Our study provides a better understanding of the role of signalling pathways in shaping the antiviral response and suggests the use of MEK inhibitors in anti-viral therapy against RV.

Association of Rhinovirus C Bronchiolitis and Immunoglobulin E Sensitization During Infancy With Development of Recurrent Wheeze

IMPORTANCE

Rhinovirus infection in early life, particularly with allergic sensitization, is associated with higher risks of developing recurrent wheeze and asthma. While emerging evidence links different rhinovirus species (eg, rhinovirus C) to a higher severity of infection and asthma exacerbation, to our knowledge, little is known about longitudinal associations of rhinovirus C infection during infancy with subsequent morbidities.

OBJECTIVE

To examine the association of different viruses (respiratory syncytial virus [RSV], rhinovirus species) in bronchiolitis with risks of developing recurrent wheeze.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter prospective cohort study of infants younger than 1 year who were hospitalized for bronchiolitis was conducted at 17 hospitals across 14 US states during 3 consecutive fall to winter seasons (2011-2014).

EXPOSURES

Major causative viruses of bronchiolitis, including RSV (reference group) and 3 rhinovirus species (rhinovirus A, B, and C).

MAIN OUTCOMES AND MEASURES

Development of recurrent wheeze (as defined in national asthma guidelines) by age 3 years.

RESULTS

This analytic cohort comprised 716 infants who were hospitalized for RSV-only or rhinovirus bronchiolitis. The median age was 2.9 months (interquartile range, 1.6-3.8 months), 541 (76%) had bronchiolitis with RSV only, 85 (12%) had rhinovirus A, 12 (2%) had rhinovirus B, and 78 (11%) had rhinovirus C infection. Overall, 231 (32%) developed recurrent wheeze by age 3 years. In the multivariable Cox model, compared with infants with RSV-only infection, the risk of recurrent wheeze was not significantly different in those with rhinovirus A or B (rhinovirus A: hazard ratio [HR], 1.27; 95% CI, 0.86-1.88; rhinovirus B: HR, 1.39; 95% CI, 0.51-3.77; both P > .10). By contrast, infants with rhinovirus C had a significantly higher risk (HR, 1.58; 95% CI, 1.08-2.32). There was a significant interaction between virus groups and IgE sensitization on the risk of recurrent wheeze (P for interaction < .01). Only infants with both rhinovirus C infection and IgE sensitization (to food or aeroallergens) during infancy had significantly higher risks of recurrent wheeze (HR, 3.03; 95% CI, 1.20-7.61). Furthermore, compared with RSV-only, rhinovirus C infection with IgE sensitization was associated with significantly higher risks of recurrent wheeze with subsequent development of asthma at age 4 years (HR, 4.06; 95% CI, 1.17-14.1).

CONCLUSIONS AND RELEVANCE

This multicenter cohort study of infants hospitalized for bronchiolitis demonstrated between-virus differences in the risk of developing recurrent wheeze. Infants with rhinovirus C infection, along with IgE sensitization, had the highest risk. This finding was driven by the association with a subtype of recurrent wheeze: children with subsequent development of asthma.

Advances in the aetiology, management, and prevention of acute asthma attacks in children

Acute attacks of wheeze or asthma are among the most common reasons for paediatric hospital attendance, and the incidence of severe attacks in the UK is among the highest in Europe. Although most attacks are driven by infection, there are important differences in the underlying pathophysiology of asthma and wheeze between preschool and school-aged children. Allergen sensitisation, airway eosinophilia, and type 2 inflammation predominate in older children, whereas phenotypes in preschool children are variable, often including non-atopic episodes driven by neutrophilic infection. Currently, a universal approach is adopted towards management, but there is a need to make objective assessments of airway function, inflammation, and infection, both during the attack and during stable periods, to identify treatable traits and to target therapy if outcomes are to be improved. An assessment of the risk factors that led to the attack and early, focused follow-up are essential to ensure attacks never occur again.

Propagation of Rhinovirus C in Differentiated Immortalized Human Airway HBEC3-KT Epithelial Cells

Rhinoviruses (RVs) are classified into three species: RV-A, B, and C. Unlike RV-A and -B, RV-C cannot be propagated using standard cell culture systems. In order to isolate RV-Cs from clinical specimens and gain a better understanding of their biological properties and pathogenesis, we established air–liquid-interface (ALI) culture methods using HBEC3-KT and HSAEC1-KT immortalized human airway epithelial cells. HBEC3- and HSAEC1-ALI cultures morphologically resembled pseudostratified epithelia with cilia and goblet cells. Two fully sequenced clinical RV-C isolates, RV-C9 and -C53, were propagated in HBEC3-ALI cultures, and increases in viral RNA ranging from 1.71 log₁₀ to 7.06 log₁₀ copies were observed. However, this propagation did not occur in HSAEC1-ALI cultures. Using the HBEC3-ALI culture system, 11 clinical strains of RV-C were isolated from 23 clinical specimens, and of them, nine were passaged and re-propagated. The 11 clinical isolates were classified as RV-C2, -C6, -C9, -C12, -C18, -C23, -C40, and -C53 types according to their VP1 sequences. Our stable HBEC3-ALI culture system is the first cultivable cell model that supports the growth of multiple RV-C virus types from clinical specimens. Thus, the HBEC3-ALI culture system provides a cheap and easy-to-use alternative to existing cell models for isolating and investigating RV-Cs.