Identification and seasonality of rhinovirus and respiratory syncytial virus in asthmatic children in tropical climate

INTRODUCTION

Asthma is a disease that has been associated with the presence of different genetic and socio-environmental factors.

OBJECTIVE

To identify and evaluate the seasonality of respiratory syncytial virus (RSV) and human rhinovirus (RV) in asthmatic children and adolescents in tropical climate, as well as to assess the socioeconomic and environmental factors involved.

METHODS

The study was conducted in a referral hospital, where a total of 151 children were recruited with a respiratory infection. The International Study of Asthma and Allergies in Childhood (ISAAC) protocol and a questionnaire were applied, and a skin prick test was performed. The nasal swab was collected to detect RV and RSV through molecular assay. National Meteorological Institute (INMET) database was the source of climatic information.

RESULTS

The socio-environmental characterization of asthmatic children showed the family history of allergy, disturbed sleep at night, dry cough, allergic rhinitis, individuals sensitized to at least one mite. We identified RV in 75% of children with asthma and 66.7% of RSV in children with asthma. There was an association between the presence of RV and the dry season whereas the presence of the RSV was associated with the rainy season. Contributing to these results, a negative correlation was observed between the RSV and the wind speed and the maximum temperature (T. Max) and a positive correlation with precipitation.

CONCLUSIONS

The results suggest a high prevalence of RV and RSV in asthmatic children and the seasonality of these viruses were present in different climatic periods. This has significant implications for understanding short- and long-term clinical complications in asthmatic patients.

If Not COVID-19 What Is It? Analysis of COVID-19 versus Common Respiratory Viruses among Symptomatic Health Care Workers in a Tertiary Infectious Disease Referral Hospital in Manila, Philippines

The COVID-19 global pandemic is entering its second year. In this short report we present additional results as a supplement to our previous paper on COVID-19 and common respiratory virus screening for healthcare workers (HCWs) in a tertiary infectious disease referral hospital in Manila, Philippines. We sought to understand what etiologic agents could explain the upper/lower respiratory tract infection-like (URTI/LRTI-like) symptoms exhibited by 88% of the 324 HCWs tested. Among the patients who had URTI/LRTI-like symptoms, only seven (2%) were positive for COVID-19, while 38 (13%) of the symptomatic participants were identified positive for another viral etiologic agent. Rhinovirus was the most common infection, with 21 (9%) of the symptomatic participants positive for rhinovirus. Based on these results, testing symptomatic HCWs for common respiratory illnesses in addition to COVID-19 should be considered during this time of global pandemic.

Increased risk of rhinovirus infection in children during the coronavirus disease-19 pandemic

Background

Coronavirus disease (COVID‐19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), was first detected in Japan in January 2020 and has spread throughout the country. Previous studies have reported that viral interference among influenza virus, rhinovirus, and other respiratory viruses can affect viral infections at the host and population level.

Methods

To investigate the impact of COVID‐19 on influenza and other respiratory virus infections, we analyzed clinical specimens collected from 2244 patients in Japan with respiratory diseases between January 2018 and September 2020.

Results

The frequency of influenza and other respiratory viruses (coxsackievirus A and B; echovirus; enterovirus; human coronavirus 229E, HKU1, NL63, and OC43; human metapneumovirus; human parainfluenza virus 1, 2, 3, and 4; human parechovirus; human respiratory syncytial virus; human adenovirus; human bocavirus; human parvovirus B19; herpes simplex virus type 1; and varicella‐zoster virus) was appreciably reduced among all patients during the COVID‐19 pandemic except for that of rhinovirus in children younger than 10 years, which was appreciably increased. COVID‐19 has not spread among this age group, suggesting an increased risk of rhinovirus infection in children.

Conclusions

Rhinovirus infections should be continuously monitored to understand their increased risk during the COVID‐19 pandemic and viral interference with SARS‐CoV‐2.

Ensemble Analysis Identifies Nasal 15-Keto-PGE2 as a Predictor of Recovery in Experimental Rhinovirus Colds

BACKGROUND

Symptom intensity during a common cold is highly variable, particularly after the illness peaks, contributing to delay in recovery. Rhinoviruses frequently cause colds and, during acute infections, generate leukotriene B4 and prostaglandin E2 (PGE2). PGE2 is known to initiate oxylipin class switching and resolution of acute inflammation. Thus, we hypothesized that during acute rhinovirus colds, oxylipins with pro-resolving capabilities reduce symptom severity and speed recovery.

METHODS

Four groups of healthy volunteers were inoculated with placebo or 3 different doses of rhinovirus A16. Participants kept daily records of symptoms and contributed serial nasal lavage fluid samples. We collected semi-quantitative mass spectrometry data for 71 oxylipins in these acute samples from all participants. An ensemble analysis approach was used to further reduce this dataset.

RESULTS

Levels of 15-keto-PGE2 at day 3 of the cold were consistently among the top candidates in these models of recovery symptoms. 15-keto-PGE2 was the only oxylipin with an interaction between inoculum dose and time. Acute 15-keto-PGE2 levels were inversely associated with symptoms during cold recovery in a multivariable analysis (P = .0043).

CONCLUSIONS

These findings show that high 15-keto-PGE2 levels during the acute cold are associated with fewer symptoms during recovery.

Rhinovirus-induced CCL17 and CCL22 in Asthma Exacerbations and Differential Regulation by STAT6

The interplay of type-2 inflammation and antiviral immunity underpins asthma exacerbation pathogenesis. Virus infection induces type-2 inflammation-promoting chemokines CCL17 and CCL22 in asthma; however, mechanisms regulating induction are poorly understood. By using a human rhinovirus (RV) challenge model in human airway epithelial cells in vitro and mice in vivo, we assessed mechanisms regulating CCL17 and CCL22 expression. Subjects with mild to moderate asthma and healthy volunteers were experimentally infected with RV and airway CCL17 and CCL22 protein quantified. In vitro airway epithelial cell- and mouse-RV infection models were then used to define STAT6- and NF-κB-mediated regulation of CCL17 and CCL22 expression. Following RV infection, CCL17 and CCL22 expression was higher in asthma, which differentially correlated with clinical and immunological parameters. Air-liquid interface-differentiated primary epithelial cells from donors with asthma also expressed higher levels of RV-induced CCL22. RV infection boosted type-2 cytokine-induced STAT6 activation. In epithelial cells, type-2 cytokines and STAT6 activation had differential effects on chemokine expression, increasing CCL17 and suppressing CCL22, whereas NF-κB promoted expression of both chemokines. In mice, RV infection activated pulmonary STAT6, which was required for CCL17 but not CCL22 expression. STAT6-knockout mice infected with RV expressed increased levels of NF-κB-regulated chemokines, which was associated with rapid viral clearance. Therefore, RV-induced upregulation of CCL17 and CCL22 was mediated by NF-κB activation, whereas expression was differentially regulated by STAT6. Together, these findings suggest that therapeutic targeting of type-2 STAT6 activation alone will not block all inflammatory pathways during RV infection in asthma.

Human rhinovirus 16 induces antiviral and inflammatory response in the human vascular endothelium

The effect of rhinovirus on airway epithelium is very well described. However, its influence on the vascular endothelium is unknown. The current study assesses the effect of rhinovirus HRV16 on the antiviral and inflammatory response in the human vascular endothelial cells (ECs). HRV16 increased IFN-β, RANTES, and IP-10 mRNA expression and protein release. HRV16 copy number in ECs reached maximal value 10 h after incubation. Increase in virus copies was accompanied by the enhancement of Toll- and RIG-I-like receptors: TLR3, RIG-I, and MDA5. Additionally, HRV16 increased OAS-1 and PKR mRNA expression, enzymes responsible for virus degradation and inhibition of replication. ICAM-1 blockade decreased HRV16 copy number in ECs and inhibited IFN-β, RANTES, IP-10, OAS1, PKR, TLR3, RIG-I, and MDA5 mRNA expression increase upon subsequent induction with HRV16. The vascular endothelium may be infected by human rhinovirus and generate antiviral and inflammatory innate response. Results of the study indicate the possible involvement of the vascular endothelium in the immunopathology of rhinoviral airway infections.

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.

Up-Regulated Vitamin D Receptor by Pelargonium sidoides Extract EPs® 7630 Contributes to Rhinovirus Defense in Bronchial Epithelial Cells

EPs^®7630, extracted from Pelargonium sidoides, reduces the severity of viral upper respiratory tract infections. Vitamin D also improves anti-viral host defense through similar signaling pathways. This study assessed if EPs^®7630 modifies vitamin D receptor (VDR) expression and function by human bronchial epithelial cells. Bronchial epithelial cells were incubated with EPs^®7630 over 48 h before calcitriol stimulation and/or infection with Rhinovirus (RV)-16. Protein expression was determined by Western-blotting. Intracellular signaling of mitogen activated protein kinases (MAPK) was studied by chemical inhibitors. The anti-viral effect was assessed by immunofluorescence for RV-16 protein. EPs^®7630 upregulated VDR expression through Erk1/2 MAPK and thereby increased the cell's sensitivity to calcitriol. Compared ton untreated cells, the shift of the VDR into the nucleus at 5.3 times lower calcitriol concentration. EPs^®7630 increased Erk1/2 MAPK signaling, but reduced p38 phosphorylation, and had no effect on Jun N-terminal kinase (JNK). EPs^®7630 improved the anti-viral effect of vitamin D on RV-16 infection by 2.1 folds compared to vitamin D alone or to untreated cells. Furthermore, EPs^®7630 improved the differentiation of epithelial cells by upregulating E-cadherin expression through Erk1/2. In conclusion, EPs^®7630 increased host defense against Rhinovirus infection by upregulating the VDR and the differentiation of epithelial cells.

Viral Loads and Disease Severity in Children with Rhinovirus-Associated Illnesses

The role of rhinoviruses (RVs) in children with clinical syndromes not classically associated with RV infections is not well understood. We analyzed a cohort of children ≤21 years old who were PCR+ for RV at a large Pediatric Hospital from 2011 to 2013. Using univariate and multivariable logistic regression, we analyzed the associations between demographic, clinical characteristics, microbiology data, and clinical outcomes in children with compatible symptoms and incidental RV detection. Of the 2473 children (inpatients and outpatients) with an RV+ PCR, 2382 (96%) had compatible symptoms, and 91 (4%) did not. The overall median age was 14 months and 78% had underlying comorbidities. No differences in RV viral loads were found according to the presence of compatible symptoms, while in children with classic RV symptoms, RV viral loads were higher in single RV infections versus RV viral co-infections. Bacterial co-infections were more common in RV incidental detection (7.6%) than in children with compatible symptoms (1.9%, p < 0.001). The presence of compatible symptoms independently increased the odds ratio (OR, 95% CI) of hospitalization 4.8 (3.1-7.4), prolonged hospital stays 1.9 (1.1-3.1), need for oxygen 12 (5.8-25.0) and pediatric intensive care unit (PICU) admission 4.13 (2.0-8.2). Thus, despite comparable RV loads, disease severity was significantly worse in children with compatible symptoms.

Specific Assay of Negative Strand Template to Quantify Intracellular Levels of Rhinovirus Double-Stranded RNA

Human rhinovirus infections are a major trigger for acute exacerbations of lower airway diseases, including asthma and chronic obstructive pulmonary disease. Disease exacerbation is thought to be regulated via double-stranded RNA (dsRNA)-mediated signaling of proinflammatory and host defense responses in airway epithelial cells. Despite the central role of dsRNA in regulating host cell responses, no method for the quantitative assessment of dsRNA levels during HRV infections has been developed. Conventional RT-PCR for the negative strand template is not effective as self-priming results in apparent signals, even in the absence of primer during reverse transcription. To avoid these issues, we developed a selective assay for the negative strand template that uses a chimeric primer containing a 5′ non-viral sequence for reverse transcription and a primer using the non-viral sequence during subsequent PCR. We established that this assay avoided issues of self-priming and is strand specific, as it is unaffected even in the presence of a 1000-fold excess of positive strand. Assays in primary human airway epithelial cells showed that negative strand was detectable within 6 h of virus exposure and peaked at 18 h after virus exposure. The temporal pattern of negative strand induction mirrored that of genomic RNA but was always 1000-fold lower than positive strand, indicating that the negative strand levels regulate levels of dsRNA formation. This assay will permit relative quantification of dsRNA during studies of HRV regulation of epithelial cell function.

Immunomodulatory Effects of Rhinovirus and Enterovirus Infections During the First Year of Life

Early childhood infections have been implicated in the development of immune-mediated diseases, such as allergies, asthma, and type 1 diabetes. We set out to investigate the immunomodulatory effects of early viral infections experienced before the age of one year on the peripheral regulatory T cell population (Treg) and circulating cytokines in a birth-cohort study of Estonian and Finnish infants. We show here a temporal association of virus infection with the expression of FOXP3 in regulatory T cells. Infants with rhinovirus infection during the preceding 30 days had a higher FOXP3 expression in Treg cells and decreased levels of several cytokines related to Th1 and Th2 responses in comparison to the children without infections. In contrast, FOXP3 expression was significantly decreased in highly activated (CD4+CD127-/loCD25+FOXP3high) regulatory T cells (TregFOXP3high) in the infants who had enterovirus infection during the preceding 30 or 60 days. After enterovirus infections, the cytokine profile showed an upregulation of Th1- and Th17-related cytokines and a decreased activation of CCL22, which is a chemokine derived from dendritic cells and associated with Th2 deviation. Our results reveal that immunoregulatory mechanisms are up-regulated after rhinovirus infections, while enterovirus infections are associated with activation of proinflammatory pathways and decreased immune regulation.

Rhinovirus bronchiolitis, maternal asthma, and the development of asthma and lung function impairments

BACKGROUND

Children with a history of rhinovirus (RV) positive bronchiolitis have a high risk of developing subsequent asthma. Maternal asthma might also increase this risk. The aim of this study was to investigate the combined effects of hospitalization for RV positive bronchiolitis in infancy and a history of maternal asthma on the development of asthma at preschool age.

METHODS

This is a prospective cohort study of 139 preschool-aged children, with a history of hospital admission for bronchiolitis in infancy, followed-up to ascertain asthma and asthma-like symptoms, skin prick allergy test positivity, and lung function measured pre- and post-bronchodilator using impulse oscillometry.

RESULTS

Children with a past hospitalization for RV positive bronchiolitis (42.4% of all) and a history of maternal asthma (36.7% of all) had the greatest prevalence and risk ratio (RR) for doctor-diagnosed asthma (prevalence 81.8% and RR 2.10, 95% confidence interval [CI] 1.37-3.19, p = .001), use of inhaled corticosteroids (68.2% and RR 2.17, 95% CI 1.19-3.99, p = .001) and short-acting β-agonists in the last 12 months (95.2% and RR 1.49, 95% CI 1.17-1.89, p = .001), as compared to those with RV negative bronchiolitis and no maternal asthma history. More children in this group had an abnormal airway resistance (33.3% and adjusted risk ratio [aRR] 3.11, 95% CI 1.03-9.47, p = .045) and reactance (27.8% and aRR 2.11, 95% CI 1.06-4.26, p = .035) at 5 Hz, as compared to those with RV negative bronchiolitis and no maternal asthma history.

CONCLUSION

Hospitalization for RV positive bronchiolitis in early life combined with a history of maternal asthma identifies a subgroup of children with a high asthma burden while participants with only one of the two risk factors had intermediate risk for asthma.

The importance of viral load in the severity of acute bronchiolitis in hospitalized infants

OBJECTIVE

The relationship between viral load and the clinical evolution of bronchiolitis is controversial. Therefore, we aimed to analyze viral loads in infants hospitalized for bronchiolitis.

METHODS

We tested for the presence of human respiratory syncytial virus (HRSV) or human rhinovirus (HRV) using quantitative molecular tests of nasopharyngeal secretions and recorded severity outcomes.

RESULTS

We included 70 infants [49 (70%) HRSV, 9 (13%) HRV and 12 (17%) HRSV+HRV]. There were no differences among the groups according to the outcomes analyzed individually. Clinical scores showed greater severity in the isolated HRSV infection group. A higher isolated HRSV viral load was associated with more prolonged ventilatory support, oxygen therapy, and hospitalization days, even after adjustment for the age and period of nasopharyngeal secretion collection. In the co-infection groups, there was a longer duration of oxygen therapy when the HRSV viral load was predominant. Isolated HRV infection and co-infection with a predominance of HRV were not associated with severity.

CONCLUSION

Higher HRSV viral load in isolated infections and the predominance of HRSV in co-infections, independent of viral load, were associated with greater severity. These results contribute to the development of therapeutic and prophylactic approaches and a greater understanding of the pathophysiology of bronchiolitis.

Clinical correlates of rhinovirus infection in preschool asthma

Background

Investigation of preschool asthma is important since not all children outgrow their illness during this age. Data are scarce on the role of rhinovirus (RV) infections in this patient group.

Objectives

To investigate the role of RV infections in preschool asthma: (i) susceptibility factors, (ii) clinical course, and (iii) medium‐term outcome.

Methods

A total of 130 asthmatic children aged 4‐6 years from the multinational PreDicta cohort were prospectively followed for a 12‐month period. Allergy tests and a standard health questionnaire were carried out at study entry. Respiratory virus presence in nasopharyngeal washes was studied at illness visits and at 3 scheduled visits.

Results

At study entry, mean age of the children was 5.3 years. Of 571 visits, 54% were positive for any virus and 39% for RV. Patient characteristics were only assessed with RV infection due to low number of other viruses. The use of supplementary vitamin D was inversely associated with RV infection (P < .05). RV infection was associated with more severe course of acute illness in terms of more severe nighttime coughing, more sleep disturbances, and more days with runny nose (all P < .05). RV infection was also associated with more severe disease course during the 12‐month follow‐up in terms of more nights with awakenings and more days of exercise‐related symptoms (both P < .05).

Conclusions

Vitamin D supplementation may have an anti‐rhinovirus effect. Both short‐ and medium‐term outcomes suggest RV infection to be an important clinical marker of instable preschool asthma.

School-Based Surveillance of Respiratory Pathogens on "High-Touch" Surfaces

In order to assess the presence of respiratory pathogens on "high-touch" surfaces and inform sanitation practices at schools, pre-selected surfaces in elementary schools in Seattle, WA, USA were sampled weekly and tested by RT-PCR for 25 viral respiratory pathogens (including SARS-CoV-2 retrospectively) and S. pneumoniae during 2019-2020 winter respiratory illness season. Viral pathogens (rhinovirus, adenovirus, influenza) known to cause respiratory illness were detected on commonly touched surfaces, especially wooden surfaces, and matched the patterns of circulating virus in the community.

Rhinovirus: A Narrative Review on Its Genetic Characteristics, Pediatric Clinical Presentations, and Pathogenesis

Human rhinoviruses (HRVs) are the leading cause of common colds. With the development of new molecular methods since the 2000s, HRVs have been increasingly involved among severe clinical infections. Recent knowledge of the HRV genetic characteristics has also improved the understanding of their pathogenesis. This narrative review aims to provide a current comprehensive knowledge about this virus in the pediatric community. HRVs represent a main cause of upper and lower respiratory tract infections in children. HRV is the second virus involved in bronchiolitis and pneumonia in children, and HRV bronchiolitis has a higher risk of recurrent wheezing episode or asthma. Some recent findings described HRVs in stools, blood, or cerebrospinal fluid, thanks to new molecular techniques such as polymerase chain reaction (PCR) by detecting HRVs with high sensibility. However, the high rate of asymptomatic carriage and the prolonged excretion in postsymptomatic patients complicate interpretation. No sufficient data exist to avoid antibiotic therapy in pediatric high-risk population with HRV detection. Severe clinical presentations due to HRVs can be more frequent in specific population with chronic pathology or genetic particularity. Inflammatory response is mediated by the nuclear factor (NF)-kappa B pathway and production of interferon (IFN)-beta and IFN-gamma, interleukin 8 (IL8), and IL1b. No specific treatment or antiviral therapy exists, although research is still ongoing. Nowadays, in addition to benign diseases, HRVs are recognized to be involved in some severe clinical presentations. Recent advances in genetic knowledge or specific inflammatory response may lead to specific treatment.

Comparison of clinically related factors and treatment approaches in patients with acute bronchiolitis

AIM

Acute bronchiolitis is a lower respiratory tract infection caused by viral agents in children aged under two years. Treatment includes hydration, oxygen, nebulized salbutamol, and intravenous steroids. This study aimed to determine the clinically related factors, the effect of viral agents on the clinical picture, and the efficacy of treatment methods in patients admitted with acute bronchiolitis.

MATERIAL AND METHODS

Patients aged under two years of age who were hospitalized with a diagnosis of moderate/severe acute bronchiolitis between March 2015 and March 2019 were included in the study. Demographic data, hospitalization time, body temperature, presence of congenital heart disease, history of atopy, acute-phase reactants, mean platelet volume values, and respiratory virus panel results were recorded. The treatment modalities, length of hospitalization, intensive care hospitalization, and high-flow nasal cannula oxygen therapy (HFNC) were recorded.

RESULTS

Four hundred twenty-two patients were included in the study. The duration of hospitalization was found to be significantly longer in patients aged under one year and in patients with acyanotic congenital heart disease. A single viral agent was detected in 69 (51.9%) patients. Rhinovirus was detected in 70 patients and RSV was detected in 37. The duration of hospitalization was found to be significantly shorter in patients who received only oxygen and/or intravenous fluid treatment compared with those who received nebulized salbutamol and/or intravenous steroids. In addition, and there was no significant difference between the groups in terms of HFNC and hospitalization in the intensive care unit.

CONCLUSION

Rhinovirus was the most common cause of acute bronchiolitis in our study. It was observed that congenital heart disease prolonged the length of hospitalization. In the treatment approaches, it was observed that hydration and oxygen therapy were sufficient treatment methods for the patients, in accordance with the recommendations of the American Academy of Pediatrics, and giving nebulized therapy prolonged the hospitalization period due to the treatment discontinuation steps.

A Microengineered Airway Lung Chip Models Key Features of Viral-induced Exacerbation of Asthma

Viral-induced exacerbation of asthma remains a major cause of hospitalization and mortality. New human-relevant models of the airways are urgently needed to understand how respiratory infections may trigger asthma attacks and to advance treatment development. Here, we describe a new human-relevant model of rhinovirus-induced asthma exacerbation that recapitulates viral infection of asthmatic airway epithelium and neutrophil transepithelial migration, and enables evaluation of immunomodulatory therapy. Specifically, a microengineered model of fully differentiated human mucociliary airway epithelium was stimulated with IL-13 to induce a T-helper cell type 2 asthmatic phenotype and infected with live human rhinovirus 16 (HRV16) to reproduce key features of viral-induced asthma exacerbation. We observed that the infection with HRV16 replicated key hallmarks of the cytopathology and inflammatory responses observed in human airways. Generation of a T-helper cell type 2 microenvironment through exogenous IL-13 stimulation induced features of asthmatic airways, including goblet cell hyperplasia, reduction of cilia beating frequency, and endothelial activation, but did not alter rhinovirus infectivity or replication. High-resolution kinetic analysis of secreted inflammatory markers revealed that IL-13 treatment altered IL-6, IFN-λ1, and CXCL10 secretion in response to HRV16. Neutrophil transepithelial migration was greatest when viral infection was combined with IL-13 treatment, whereas treatment with MK-7123, a CXCR2 antagonist, reduced neutrophil diapedesis in all conditions. In conclusion, our microengineered Airway Lung-Chip provides a novel human-relevant platform for exploring the complex mechanisms underlying viral-induced asthma exacerbation. Our data suggest that IL-13 may impair the hosts' ability to mount an appropriate and coordinated immune response to rhinovirus infection. We also show that the Airway Lung-Chip can be used to assess the efficacy of modulators of the immune response.

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.

Impaired interferon-α expression in plasmacytoid dendritic cells in asthma

Background

Toll‐like receptor (TLR)‐7‐associated rhinovirus (RV) activation is involved in the pathogenesis of asthma. Plasmacytoid dendritic cells (pDCs) are the main interferon‐α‐producing cells against viruses.

Objective

To determine whether asthmatic patients and control subjects differ in terms of interferon‐α expression in pDCs under TLR‐7 or RV stimulation.

Methods

pDCs were identified in BDCA‐2+ and HLA‐DR+ peripheral blood mononuclear cells. Interferon‐α expression of pDCs was analyzed after TLR‐7 stimulation with or without interleukin 4 (IL‐4)/IL‐13 pretreatment. Interferon‐α expression was also analyzed after RV stimulation over periods of 24, 48, or 96 h with or without IL‐4 pretreatment. RV detection and molecular typing were assayed from throat swabs.

Results

Following TLR‐7 stimulation, the expression of intracellular interferon‐α was higher in the pDCs of normal subjects than those of asthmatic patients; however, pretreatment with IL‐4 was shown to reduce this effect. After 48‐ and 96‐h RV stimulation, we observed a notable increase in the production of interferon‐α of pDCs in normal subjects but not in asthmatic patients. Baseline interferon‐α expression in pDCs and the incidence of asthma exacerbation to emergency was higher among the 13% of patients identified as rhinovirus+ than among their RV counterparts.

Conclusion

Our study discovered the response to TLR‐7 stimulation in pDCs was compromised and the sustainability of interferon‐α expression to RV stimulation was reduced in pDCs of asthmatic patients, which provide further evidence of defective innate response and subspeciality to RV infection in asthma. The high exacerbation history founded in RV+ patients agrees with these findings. Further research is required for the modulatory effect of IL‐4 on TLR‐7 stimulated pDCs.

Human rhinovirus-specific CD8 T cell responses target conserved and unusual epitopes

Human Rhinovirus (HRV) is a major cause of common cold, bronchiolitis, and exacerbations of chronic pulmonary diseases such as asthma. CD8 T cell responses likely play an important role in the control of HRV infection but, surprisingly, HRV‐specific CD8 T cell epitopes remain yet to be identified. Here, we approached the discovery and characterization of conserved HRV‐specific CD8 T cell epitopes from species A (HRV A) and C (HRV C), the most frequent subtypes in the clinics of various pulmonary diseases. We found IFNγ‐ELISPOT positive responses to 23 conserved HRV‐specific peptides on peripheral blood mononuclear cells (PBMCs) from 14 HLA I typed subjects. Peptide‐specific IFNγ production by CD8 T cells and binding to the relevant HLA I were confirmed for six HRV A‐specific and three HRV C‐specific CD8 T cell epitopes. In addition, we validated A*02:01‐restricted epitopes by DimerX staining and found out that these peptides mediated cytotoxicity. All these A*02:01‐restricted epitopes were 9‐mers but, interestingly, we also identified and validated an unusually long 16‐mer epitope peptide restricted by A*02:01, HRVC_1791‐1806 (GLEPLDLNTSAGFPYV). HRV‐specific CD8 T cell epitopes describe here are expected to elicit CD8 T cell responses in up to 87% of the population and could be key for developing an HRV vaccine.

Rhinovirus and asthma: Challenges and opportunities

Human rhinoviruses (RVs) are the primary aetiological agent of the common cold. Generally, the associated infection is mild and self‐limiting, but may also be associated with bronchiolitis in infants, pneumonia in the immunocompromised and exacerbation in patients with pulmonary conditions such as asthma or chronic obstructive pulmonary disease. Viral infection accounts for as many as two thirds of asthma exacerbations in children and more than half in adults. Allergy and asthma are major risk factors for more frequent and severe RV‐related illnesses. The prevalence of RV‐induced wheezing will likely continue to increase given that asthma affects a significant proportion of the population, with allergic asthma accounting for the majority. Several new respiratory viruses and their subgroups have been discovered, with various degrees of relevance. This review will focus on RV infection in the context of the epidemiologic evidence, genetic variability, pathobiology, clinical studies in the context of asthma, differences with other viruses including COVID‐19 and current treatment interventions.

An adapted novel flow cytometry methodology to delineate types of cell death in airway epithelial cells

Current methodologies to measure apoptotic and necrotic cell death using flow cytometry do not adequately differentiate between the two. Here, we describe a flow cytometry methodology adapted to airway epithelial cells (AEC) to sufficiently differentiate apoptotic and necrotic AEC. Specifically, cell lines and primary AEC (n = 12) were permeabilized or infected with rhinovirus 1b (RV1b) over 48 h. Cell death was then measured via annexin V/propidium iodide (A5/PI) or annexin V/TO-PRO-3 (A5/TP3) staining using a novel flow cytometry and gating methodology adapted to AEC. We show that A5/PI staining could not sufficiently differentiate between types of cell death following RV1b infection of primary AEC. However, A5/TP3 staining was able to distinguish six cell death populations (viable, necrotic, debris, A5⁺ apoptotic, A5^– apoptotic, apoptotic bodies) after permeabilization or infection with RV1b, with phenotypic differences were observed in apoptotic populations. Collectively, using a staining and gating strategy never adapted to AEC, A5/TP3 could accurately differentiate and quantify viable, necrotic, and apoptotic AEC following RV1b infection.

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.