Human bocavirus 1 may suppress rhinovirus-associated immune response in wheezing children

B cell immune response to human bocaviruses

BACKGROUND

Human bocaviruses (HBoVs) have been demonstrated in respiratory and gastrointestinal infections; however, the immune response to them has not been studied in detail. In this study, we investigated the B cell immune responses to HBoV1 and HBoV2, representing two different species of bocaviruses in humans.

METHODS

We analyzed the effects of stimulations with HBoV1 and 2 virus-like particles (VLPs) and of co-stimulation with HBoV1-rhinovirus (RV) on cells of the immune system by flow cytometry, transcriptomics, and luminometric immune assays.

RESULTS

Human B cells, and particularly B regulatory cells (Breg cells), showed an increased immune response to HBoV1-VLPs stimulation. These immune responses were also supported by increased IL-1RA and PDL1 expressions in IL-10+ B cells from peripheral blood mononuclear cells (PBMCs) stimulated with HBoV1-VLPs. In addition, increased levels of IL-10 and IL-1RA were determined in the supernatants of PBMCs following HBoV1-VLPs stimulation. HBoV1-VLPs and RV co-stimulation increased the IL-10+ B cell population. Transcriptome analysis by next-generation RNA sequencing showed an increased expression of IL-10 signalling and Breg cell markers in PBMCs stimulated with HBoV1-VLPs. Furthermore, TGF-β and chemoattractants MIP-1α, MIP-1β and IP10 protein levels were high in the supernatants of PBMCs stimulated with HBoV1-VLPs.

CONCLUSIONS

The findings demonstrate that in Breg cells, IL-10 signalling pathways, and anti-inflammatory activity are induced by HBoV1, which can explain the often mild nature of the disease. In addition, the immune regulatory response induced by HBoV1-VLPs may indicate a potential immunomodulatory role of HBoV1 on the immune system and may represent an immune regulatory strategy.

Human bocavirus respiratory infection: Tracing the path from viral replication and virus-cell interactions to diagnostic methods

Human bocaviruses were first described between 2005 and 2010, identified in respiratory and enteric tract samples of children. Screening studies have shown worldwide distribution. Based on phylogenetic analysis, they were classified into four genotypes (HBoV1-4). From a clinical perspective, human bocavirus 1 (HBoV1) is considered the most relevant, since it can cause upper and lower acute respiratory tract infection, mainly in infants, including common cold, bronchiolitis, and pneumonia, as well as wheezing in susceptible patients. However, the specific processes leading to structural, biochemical, and functional changes resulting in the different clinical presentations have not been elucidated yet. This review surveys the interactions between the virus and target cells that can potentially explain disease-causing mechanisms. It also summarises the clinical phenotype of cases, stressing the role of HBoV1 as an aetiological agent of lower acute respiratory infection in infants, together with laboratory tests for detection and diagnosis. By exploring the current knowledge on the epidemiology of HBoV1, insights into the complex scenario of paediatric respiratory infections are presented, as well as the potential effects that changes in the circulation can have on the dynamics of respiratory agents, spotlighting the benefits of comprehensively increase insights into incidence, interrelationships with co-circulating agents and potential control of HBoV1.

Human bocavirus 1 coinfection is associated with decreased cytokine expression in the rhinovirus-induced first wheezing episode in children

BACKGROUND

Rhinovirus (RV)-induced first wheezing episodes in children are associated with a markedly increased risk of asthma. Previous studies have suggested that human bocavirus 1 (HBoV1) may modify RV-induced immune responses in young children. We investigated cytokine profiles of sole RV- and dual RV-HBoV1-induced first wheezing episodes, and their association with severity and prognosis.

METHODS

Fifty-two children infected with only RV and nine children infected with dual RV-HBoV1, aged 3-23 months, with severe first wheezing episodes were recruited. At acute illness and 2 weeks later, peripheral blood mononuclear cells were isolated, and stimulated with anti-CD3/anti-CD28 in vitro. Multiplex ELISA was used to quantitatively identify 56 different cytokines at both study points. Patients were prospectively followed for 4 years.

RESULTS

The mean age of the children was 14.3 months, and 30% were sensitized. During the acute illness, the adjusted analyses revealed a decrease in the expression of IL-1b, MIP-1b, Regulated upon activation, normal T cell expressed and presumably secreted (CCL5), TNF-a, TARC, and ENA-78 in the RV-HBoV1 group compared with the RV group. In the convalescence phase, the RV-HBoV1 group was characterized by decreased expression of Fractalkine, MCP-3, and IL-8 compared to the RV group. Furthermore, the hospitalization time was associated with the virus group and cytokine response (interaction p < 0.05), signifying that increased levels of epidermal growth factor and MIP-1b were related with a shorter duration of hospitalization in the RV-HBoV1 coinfection group but not in the RV group.

CONCLUSIONS

Different cytokine response profiles were detected between the RV and the RV-HBoV1 groups. Our results show the idea that RV-induced immune responses may be suppressed by HBoV1.

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.

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.

Respiratory virome profiles reflect antiviral immune responses

BACKGROUND

From early life, respiratory viruses are implicated in the development, exacerbation and persistence of respiratory conditions such as asthma. Complex dynamics between microbial communities and host immune responses shape immune maturation and homeostasis, influencing health outcomes. We evaluated the hypothesis that the respiratory virome is linked to systemic immune responses, using peripheral blood and nasopharyngeal swab samples from preschool-age children in the PreDicta cohort.

METHODS

Peripheral blood mononuclear cells from 51 children (32 asthmatics and 19 healthy controls) participating in the 2-year multinational PreDicta cohort were cultured with bacterial (Bacterial-DNA, LPS) or viral (R848, Poly:IC, RV) stimuli. Supernatants were analysed by Luminex for the presence of 22 relevant cytokines. Virome composition was obtained using untargeted high throughput sequencing of nasopharyngeal samples. The metagenomic data were used for the characterization of virome profiles and the presence of key viral families (Picornaviridae, Anelloviridae, Siphoviridae). These were correlated to cytokine secretion patterns, identified through hierarchical clustering and principal component analysis.

RESULTS

High spontaneous cytokine release was associated with increased presence of Prokaryotic virome profiles and reduced presence of Eukaryotic and Anellovirus profiles. Antibacterial responses did not correlate with specific viral families or virome profile; however, low antiviral responders had more Prokaryotic and less Eukaryotic virome profiles. Anelloviruses and Anellovirus-dominated profiles were equally distributed among immune response clusters. The presence of Picornaviridae and Siphoviridae was associated with low interferon-λ responses. Asthma or allergy did not modify these correlations.

CONCLUSION

Antiviral cytokine responses at a systemic level reflect the upper airway virome composition. Individuals with low innate interferon responses have higher abundance of Picornaviruses (mostly Rhinoviruses) and bacteriophages. Bacteriophages, particularly Siphoviridae, appear to be sensitive sensors of host antimicrobial capacity, while Anelloviruses are not correlated with TLR-induced immune responses.

Herpesvirus infections in adenoids in patients with chronic adenotonsillar disease

Adenoids and tonsils have gained interest as a new in vivo model to study local immune functions and virus reservoirs. Especially herpesviruses are interesting because their prevalence and persistence in local lymphoid tissue are incompletely known. Our aim was to study herpesvirus and common respiratory virus infections in nonacutely ill adenotonsillar surgery patients. Adenoid and/or palatine tonsil tissue and nasopharyngeal aspirate (NPA) samples were collected from elective adenoidectomy (n = 45) and adenotonsillectomy (n = 44) patients (median age: 5, range: 1–20). Real‐time polymerase chain reaction was used to detect 22 distinct viruses from collected samples. The overall prevalence of herpesviruses was 89% and respiratory viruses 94%. Human herpesviruses 6 (HHV6), 7 (HHV7), and Epstein–Barr virus (EBV) were found, respectively, in adenoids (33%, 26%, 25%), tonsils (45%, 52%, 23%), and NPA (46%, 38%, 25%). Copy numbers of the HHV6 and HHV7 genome were significantly higher in tonsils than in adenoids. Patients with intra‐adenoid HHV6 were younger than those without. Detection rates of EBV and HHV7 showed agreement between corresponding sample types. This study shows that adenoid and tonsil tissues commonly harbor human herpes‐ and respiratory viruses, and it shows the differences in virus findings between sample types.

Persistent human bocavirus 1 infection and tonsillar immune responses

BACKGROUND

Persistent human bocavirus 1 (HBoV1) infection is a common finding in patients suffering from chronic tonsillar disease. However, the associations between HBoV1 infection and specific immune reactions are not completely known. We aimed to compare in vivo expression of T-cell cytokines, transcription factors, and type I/III interferons in human tonsils between HBoV1-positive and -negative tonsillectomy patients.

METHODS

Tonsil tissue samples, nasopharyngeal aspirate (NPA), and serum samples were obtained from 143 immunocompetent adult and child tonsillectomy patients. HBoV1 and 14 other respiratory viruses were detected in NPAs and tonsil tissues by polymerase chain reaction (PCR). Serology and semi-quantitative PCR were used for diagnosing HBoV1 infections. Expression of 14 cytokines and 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, Tbet) was analyzed by quantitative reverse-transcription (RT)-PCR in tonsil tissues.

RESULTS

HBoV1 was detected by PCR in NPA and tonsils from 25 (17%) study patients. Serology results indicated prior nonacute infections in 81% of cases. Tonsillar cytokine responses were affected by HBoV1 infection. The suppression of two transcription factors, RORC2 and FOXP3, was associated with HBoV1 infection (p < 0.05). Furthermore, intratonsillar HBoV1-DNA loads correlated negatively with IFN-λ family cytokines and IL-13.

CONCLUSIONS

Our study shows distinctively decreased T-helper17 and T-regulatory type immune responses in local lymphoid tissue in HBoV1-positive tonsillectomy patients. HBoV1 may act as a suppressive immune modulator.

Clinical Characteristics of Pediatric Respiratory Tract Infection and Respiratory Pathogen Isolation During the Coronavirus Disease 2019 Pandemic

Objective: We sought to compare the clinical characteristics of pediatric respiratory tract infection and respiratory pathogen isolations during the coronavirus disease (COVID-19) pandemic to those of cases in 2018 and 2019. Methods: Our study included all children from 28 days to 15 years old with respiratory tract infections who were admitted to the Department of Respiration, in the Children's Hospital of Soochow University, between January 2018 and December 2020. Human rhinovirus (HRV) and human metapneumovirus (hMPV) were detected by reverse transcription polymerase chain reaction (RT-PCR). Mycoplasma pneumoniae (MP) and human bocavirus (HBoV) were detected by real-time fluorescence quantitative polymerase chain reaction (qPCR); In parallel, Mycoplasma pneumoniae was detected by enzyme-linked immunosorbent assays, and bacteria were detected by culture in blood, bronchoalveolar lavage specimen, and pleural fluid. Results: Compared to 2018 and 2019, the pathogen detection rate was significantly lower in 2020. With regard to infections caused by single pathogens, in 2020, the detection rates of MP were the lowest and those of HRV were the highest when compared to those in 2018 and 2019. Meanwhile, the positive rates of respiratory syncytial virus (RSV) and hMPV reported in 2020 were less than those recorded in 2018 but similar to those recorded in 2019. Also, the 2020 rate of adenovirus (ADV) was lower than that recorded in 2019, but similar to that recorded in 2018. There were no statistical differences in the positive rates of HBoV and PIV III over the 3 years surveyed. Infections in infants were significantly less common in 2020, but no significant difference was found among children aged 1 to 3 years. The detection rate of pathogens in children old than 5 years in 2020 was significantly lower than those recorded in the previous 2 years. Notably, the pathogen detection rates in the first and second quarters of 2020 were similar to those recorded in the previous 2 years; however, the rates were reduced in the third and fourth quarters of 2020. As for co-infections, the positive rate was at its lowest in 2020. In the previous 2 years, viral-MP was the most common type of mixed infection. By contrast, in 2020, viral-viral infections were the most common combination. Conclusion: The pathogen detection rate was significantly reduced in Suzhou City during the COVID-19 pandemic. Public interventions may help to prevent respiratory pathogen infections in children.

Human bocavirus and metapneumovirus in acute wheezing in children-Is there a link with atopy?

INTRODUCTION

Viral respiratory tract infections are the leading cause of acute wheezing in children with a significant risk of hospital admission, risk of recurrence and subsequent asthma. Human respiratory syncytial virus (RSV) and human rhinovirus (RV) in childhood wheezing are widely studied; however, accessible PCR assays enabled diagnosis of other pathogens, including bocavirus (hBOV) and metapneumovirus (hMPV).

OBJECTIVES

The aim of the study was to evaluate the prevalence of respiratory viruses in children hospitalized for acute wheezing along with demographic and clinical data.

METHODS

We enrolled 101 children, n = 50 (49.5%) with wheezy bronchitis, n = 34 (33.7%) with acute bronchiolitis and n = 17 (16.8%) with exacerbation of asthma; (median age 1.41 ± 2.84 years). Multiplex real-time PCR assay was used for virus detection.

RESULTS

One or more viruses were detected in 83.2% subjects: RSV in 44.6%, followed by RV (23.8%), hBOV and hMPV (both 11.9%); other viruses were less frequent (<8%). Viral coinfection was found in 38 (37.6%) of children. ANCOVA analysis revealed significantly higher total IgE concentrations in the hMPV-positive subgroup compared to RSV (34 kU/L vs 12.7 kU/L; P = .009) and RV (13.3 kU/L, P = .022). For both hMPV and hBOV an association with atopic dermatitis (AD) was observed: aOR for hMPV and AD was 5.6 (95%CI: 1.4-22.7; P = .016) and 4.7 for hBOV and AD (95%CI: 1.3-18; P = .024).

CONCLUSION

Viral detection ratio in wheezy respiratory tract infections in Polish children is high (83.2%), with both hBOV and hMPV at 11.9% The results also suggest possible relationship of hBOV wheezy infection with nonspecific markers of atopy in children.

Beyond Respiratory Syncytial Virus and Rhinovirus in the Pathogenesis and Exacerbation of Asthma: The Role of Metapneumovirus, Bocavirus and Influenza Virus

Respiratory viruses other than rhinovirus or respiratory syncytial virus, including human metapneumovirus, influenza virus, and human bocavirus, are important pathogens in acute wheezing illness and asthma exacerbations in young children. Whether infection with these viruses in early life is associated with recurrent wheezing and/or asthma is not fully investigated, although there are data to suggest children with human metapneumovirus lower respiratory tract infection may have a higher likelihood of subsequent and recurrent wheezing several years after initial infection.

Human bocaviruses and paediatric infections

Human bocavirus 1 (HBoV1), belonging to the Parvoviridae family, was discovered in 2005, in nasopharyngeal samples from children with respiratory tract infections. Three additional bocaviruses, HBoV2-4, were discovered in 2009-10. These viruses have mainly been found in faecal samples and their role in human diseases is still uncertain. HBoV1 causes a wide spectrum of respiratory diseases in children, including common cold, acute otitis media, pneumonia, bronchiolitis, and asthma exacerbations. HBoV1 DNA can persist in airway secretions for months after an acute infection. Consequently, acute HBoV1 infection cannot be diagnosed with standard DNA PCR; quantitative PCR and serology are better diagnostic approaches. Because of their high clinical specificity, diagnostic developments such as HBoV1 mRNA and antigen detection have shown promising results. This Review summarises the knowledge on human bocaviruses, with a special focus on HBoV1.

Role of viral coinfections in asthma development

Background

Viral respiratory infections, especially acute bronchiolitis, play a key role in the development of asthma in childhood. However, most studies have focused on respiratory syncytial virus or rhinovirus infections and none of them have compared the long-term evolution of single versus double or multiple viral infections.

Objective

Our aim was to compare the frequency of asthma development at 6–8 years in children with previous admission for bronchiolitis associated with single versus double or multiple viral infection.

Patients & methods

A cross-sectional study was performed in 244 children currently aged 6–8 years, previously admitted due to bronchiolitis between September 2008 and December 2011. A structured clinical interview and the ISAAC questionnaire for asthma symptoms for 6-7-year-old children, were answered by parents by telephone. Specimens of nasopharyngeal aspirate for virological study (polymerase chain reaction) and clinical data were prospectively taken during admission for bronchiolitis.

Results

Median current age at follow-up was 7.3 years (IQR: 6.7–8.1). The rate of recurrent wheezing was 82.7% in the coinfection group and 69.7% in the single-infection group, p = 0.06. The number of wheezing-related admissions was twice as high in coinfections than in single infections, p = 0.004. Regarding the ISAAC questionnaire, 30.8% of coinfections versus 15% of single infections, p = 0.01, presented “wheezing in the last 12 months”, data that strongly correlate with current prevalence of asthma. “Dry cough at night” was also reported more frequently in coinfections than in single infections, p = 0.02. The strongest independent risk factors for asthma at 6–8 years of age were: age > 9 months at admission for bronchiolitis (OR: 3.484; CI95%: 1.459–8.317, p:0.005), allergic rhinitis (OR: 5.910; 95%CI: 2.622–13.318, p<0.001), and viral coinfection-bronchiolitis (OR: 3.374; CI95%: 1.542–7.386, p:0.01).

Conclusions

Asthma at 6–8 years is more frequent and severe in those children previously hospitalized with viral coinfection-bronchiolitis compared with those with single infection. Allergic rhinitis and older age at admission seem also to be strong independent risk factors for asthma development in children previously hospitalised because of bronchiolitis.

Thymic stromal lymphopoietin, IL-33, and periostin in hospitalized infants with viral bronchiolitis

Much attention has recently been focused on thymic stromal lymphopoietin (TSLP), IL-33, and periostin in allergic disease, but less is known about their role in viral bronchiolitis.The aim of the study was to investigate whether infants exhibit enhanced nasal airway secretion of TSLP, IL-33, and periostin during natural respiratory viral bronchiolitis compared to healthy controls.In total, 213 infants < 2 years of age, hospitalized with bronchiolitis from October/2013 to April/2016 were enrolled alongside 45 healthy infants. Nasopharyngeal aspirates (NPA) were screened for respiratory viruses by the polymerase chain reaction. TSLP, IL-33, and periostin were measured in NPAs. Clinical data were recorded.At least 1 virus was detected in 186 (87.3%) hospitalized infants: 149 (70%) respiratory syncytial virus (RSV); 42 (19.7%) rhinovirus (HRV); 16 (7.5%) parainfluenza virus (PIV); 9 (4.2%) adenovirus; 10 (4.7%) bocavirus; and 7 (3.3%) metapneumovirus (hMPV). Infants with bronchiolitis had higher levels of TSLP (P = .02), IL-33 (P<.001), and periostin (P = .003) than healthy controls.Detectable levels of TSLP and periostin were more frequent in virus-positive than in virus-negative patients (P = .05). TSLP and IL-33 were also more common in coinfections, mainly RSV and HRV, than in single-infections (P < .05). No patient with bronchiolitis but with negative viral detection had detectable levels of nasal TSLP or IL-33. Infants with hospital stay ≥5 days were more likely to have detectable levels of nasal TSLP and periostin after adjusting by age (P = .01).Bronchiolitis by common respiratory viruses is associated with elevated nasal levels of TSLP, IL-33, and periostin, factors known to be important in the development of Th2-response. Respiratory viruses in early life might shift immune responses toward Th2, involving asthma, and allergic diseases.

Mechanisms of Aeroallergen Immunotherapy: Subcutaneous Immunotherapy and Sublingual Immunotherapy

Allergen immunotherapy (AIT) is an effective way to treat allergic disorders, targeting the underlying mechanisms and altering the disease course by inducing a long-lasting clinical and immune tolerance to allergens. Although sublingual and subcutaneous routes are used in daily practice, many novel ways to decrease side effects and duration and increase efficacy have been pursued. Further studies are needed to develop biomarkers for the identification of AIT responder patients and also to use the developed knowledge in allergy prevention studies. Future directions in AIT include treatments for autoimmune diseases, chronic infections, organ transplantation, and breaking immune tolerance to cancer cells.

Human Bocavirus NS1 and NS1-70 Proteins Inhibit TNF-α-Mediated Activation of NF-κB by targeting p65

Human bocavirus (HBoV), a parvovirus, is a single-stranded DNA etiologic agent causing lower respiratory tract infections in young children worldwide. Nuclear factor kappa B (NF-κB) transcription factors play crucial roles in clearance of invading viruses through activation of many physiological processes. Previous investigation showed that HBoV infection could significantly upregulate the level of TNF-α which is a strong NF-κB stimulator. Here we investigated whether HBoV proteins modulate TNF-α–mediated activation of the NF-κB signaling pathway. We showed that HBoV NS1 and NS1-70 proteins blocked NF-κB activation in response to TNF-α. Overexpression of TNF receptor-associated factor 2 (TRAF2)-, IκB kinase alpha (IKKα)-, IκB kinase beta (IKKβ)-, constitutively active mutant of IKKβ (IKKβ SS/EE)-, or p65-induced NF-κB activation was inhibited by NS1 and NS1-70. Furthermore, NS1 and NS1-70 didn’t interfere with TNF-α-mediated IκBα phosphorylation and degradation, nor p65 nuclear translocation. Coimmunoprecipitation assays confirmed the interaction of both NS1 and NS1-70 with p65. Of note, NS1 but not NS1-70 inhibited TNF-α-mediated p65 phosphorylation at ser536. Our findings together indicate that HBoV NS1 and NS1-70 inhibit NF-κB activation. This is the first time that HBoV has been shown to inhibit NF-κB activation, revealing a potential immune-evasion mechanism that is likely important for HBoV pathogenesis.

Advances in environmental and occupational disorders in 2014

In 2014, the Journal published a number of studies that have advanced our understanding of the effects of various environmental factors and immune responses in patients with allergic diseases. In this review we emphasize reports that have appeared in the Journal over the past year that deal with environmental and occupational respiratory disorders and novel approaches to their treatment. The review will focus on the effects of environmental factors and immune responses in allergic airway diseases, identification of new allergens, and risk factors in stinging insect allergy, development of asthma in different age groups, effects of viral infections, and benefits of new therapies.

The first wheezing episode: respiratory virus etiology, atopic characteristics, and illness severity

BACKGROUND

Susceptibility to early rhinovirus-induced wheezing has been recognized as an important risk factor for childhood asthma, but data on the first wheezing episode are limited. The aim of this selected population study was to investigate virus etiology, atopic characteristics, and illness severity, as well as their interrelation, among first-time wheezing children.

METHODS

We studied 111 first-time wheezing children aged between 3 and 23 months (88/23 in-/outpatients). The investigated factors included atopy, food, perennial and aeroallergen sensitization, eczema, atopic eczema, elevated blood eosinophil count, and parental allergic rhinitis, asthma, and smoking. Nasopharyngeal aspirates were analyzed for adenovirus, coronaviruses, enteroviruses, bocavirus-1 (also serologically confirmed), influenza viruses, metapneumovirus, parainfluenza viruses, rhinovirus, and respiratory syncytial virus using PCR methods.

RESULTS

The mean age of the study patients was 12 months (standard deviation 6.0). Atopic characteristics could be found in 56%, atopic eczema in 16%, and sensitization in 23% of the cases. In all samples (100%), ≥1 viruses were detected as follows: rhinovirus (76%), respiratory syncytial virus (29%), bocavirus (18%, acute infections), and other viruses <10% each. Virus coinfections occurred in 38% of the children. Rhinovirus infection was positively associated with age, blood eosinophil count, eczema, and duration of cough, as well as parental allergic rhinitis and smoking but negatively associated with virus coinfection (all p < 0.05).

CONCLUSIONS

A respiratory virus infection can be detected in all first-time wheezing children. Rhinovirus dominated the findings and was linked to atopic characteristics, prolonged cough, and parental smoking.