Relationship of early childhood viral exposures to respiratory symptoms, onset of possible asthma and atopy in high risk children: the Canadian Asthma Primary Prevention Study

Microarray-Based Analyses of Rhinovirus Species-Specific Antibody Responses in Exacerbated Pediatric Asthma in a German Pediatric Cohort

Rhinoviruses (RV) account for a significant number of asthma exacerbations, and RV species C may be associated with a severe course in vulnerable patient groups. Despite important evidence on the role of RV reported by clinicians and life scientists, there are still unanswered questions regarding their influence on asthma exacerbation in young patients. Thus, we measured the RVspecies-specific IgG titers in our German pediatric exacerbation cohort using a microarray-based technology. For this approach, human sera of patients with exacerbated asthma and wheeze, as well as healthy control subjects (n = 136) were included, and correlation analyses were performed. Concordantly with previously published results, we observed significantly higher cumulative levels of RV species A-specific IgG (p = 0.011) and RV-C-specific IgG (p = 0.051) in exacerbated asthma group compared to age-matched controls. Moreover, atopic wheezers had increased RV-specific IgG levels for species A (p = 0.0011) and species C (p = 0.0009) compared to non-atopic wheezers. Hypothesizing that bacterial infection positively correlates with immune memory against RV, we included nasopharyngeal swab results in our analyses and detected limited correlations. Interestingly, the eosinophil blood titer positively correlated with RV-specific IgG levels. With these observations, we add important observations to the existing data regarding exacerbation in pediatric and adolescent medicine. We propose that scientists and clinicians should pay more attention to the relevance of RV species in susceptible pediatric patients.

The Role of Atopy in COPD and Asthma

Common to several allergic diseases is the generation of immunoglobulin E (IgE) by plasma cells, when exposed to an innocuous antigen. Asthma and chronic obstructive pulmonary disease (COPD) are two prevalent chronic airway inflammatory diseases. Asthma is mediated in some patients through eosinophilic inflammatory mechanisms that include allergic sensitization and Th2-mediated immune airway response. COPD, on the other hand is mainly considered a Th1-mediated inflammatory process with neutrophilic predominance or a non-Th2 inflammation, occasionally associated with the presence of airway bacteria or viruses. IgE production appears to play an important role in the development of both COPD and asthma, as it has been associated to respiratory symptoms, lung function, bacterial and viral infections, airway remodeling and bronchial hyperreactivity in both diseases. The aim of this review is to summarize all current data concerning the role of specific and total IgE in COPD and asthma and to highlight similarities and differences in view of possible therapeutic interventions.

Association between early bronchiolitis and the development of childhood asthma: a meta-analysis

OBJECTIVE

Early life bronchiolitis has been hypothesised to be associated with the subsequent risk of persistent wheezing or asthma. However, the link remains controversial. The objective of our study was to evaluate the association between bronchiolitis before 2 years of age and the late-onset wheezing/asthma.

DESIGN

Systematic review and meta-analysis.

METHODS

PubMed, Embase and Web of Science databases were systematically searched for studies published between 1955 and January 2020. Meanwhile, we also checked through the reference lists of relevant articles to see whether these references included reports of other studies that might be eligible for the review. Cohort and case-control studies assessing the association between early-life bronchiolitis and late-onset wheezing/asthma were included in this meta-analysis. Data were extracted by two independent reviewers. Results were pooled using a random-effects model or fixed-effects model according to the heterogeneity among studies.

RESULTS

32 original articles with 292 844 participants, which met the criteria, were included in this meta-analysis. Bronchiolitis before 2 years of age was associated with an increased risk of subsequent wheezing/asthma (relative risk=2.46, 95% CI 2.14 to 2.82, p<0.001). After categorising studies into different groups based on age at the end of follow-up, geographical region and study quality, the association still remained significant.

CONCLUSIONS

The meta-analysis indicates an association between bronchiolitis before 2 years of age and the wheezing/asthma in later life. Well-designed and highly standardised prospective studies that better address bias due to potential confounding factors are needed to validate the risk identified in our meta-analysis.PROSPERO registration numberCRD42018089453.

Trajectories of early-onset rhinitis in the Singapore GUSTO mother-offspring cohort

BACKGROUND

The natural history of childhood rhinitis is not well described.

OBJECTIVE

This study aimed to identify different rhinitis trajectories in early childhood and their predictors and allergic associations.

METHODS

Rhinitis symptoms were ascertained prospectively from birth until 6 years using standardized questionnaires in 772 participants. Rhinitis was defined as one or more episodes of sneezing, runny and/or blocked nose >2 weeks duration. Latent trajectories were identified using group-based modelling, and their predictive risk factors and allergic associations were examined.

RESULTS

Three rhinitis trajectory groups were identified: 7.6% (n = 59) were termed early transient rhinitis, 8.6% (n = 66) late transient rhinitis, and 6.6% (n = 51) persistent rhinitis. The remaining 77.2% (n = 596) were classified as non-rhinitis/reference group. Early transient rhinitis subjects were more likely of Indian ethnicity, had siblings, reported childcare attendance, early wheezing and eczema in the first 3 years of life. Late transient rhinitis was associated with antenatal exposure to smoking, higher maternal education levels, and wheezing at age 36-72 months. Persistent rhinitis was associated with male gender, paternal and maternal history of atopy, eczema, and house dust mite sensitization.

CONCLUSIONS & CLINICAL RELEVANCE

Risk factors for early transient rhinitis involve a combination of genetic and early environmental exposures, whereas late transient rhinitis may relate to maternal factors and early respiratory infections independent of atopy. In contrast, persistent rhinitis is strongly associated with atopic risk and likely represents the typical trajectory associated with allergic disorders. Allergic rhinitis symptoms may commence as early as the first year of life and may inform development of early interventive strategies.

Does respiratory syncytial virus lower respiratory illness in early life cause recurrent wheeze of early childhood and asthma? Critical review of the evidence and guidance for future studies from a World Health Organization-sponsored meeting

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) and hospitalization in infants and children globally. Many observational studies have found an association between RSV LRTI in early life and subsequent respiratory morbidity, including recurrent wheeze of early childhood (RWEC) and asthma. Conversely, two randomized placebo-controlled trials of efficacious anti-RSV monoclonal antibodies (mAbs) in heterogenous infant populations found no difference in physician-diagnosed RWEC or asthma by treatment group. If a causal association exists and RSV vaccines and mAbs can prevent a substantial fraction of RWEC/asthma, the full public health value of these interventions would markedly increase. The primary alternative interpretation of the observational data is that RSV LRTI in early life is a marker of an underlying predisposition for the development of RWEC and asthma. If this is the case, RSV vaccines and mAbs would not necessarily be expected to impact these outcomes. To evaluate whether the available evidence supports a causal association between RSV LRTI and RWEC/asthma and to provide guidance for future studies, the World Health Organization convened a meeting of subject matter experts on February 12-13, 2019 in Geneva, Switzerland. After discussing relevant background information and reviewing the current epidemiologic evidence, the group determined that: (i) the evidence is inconclusive in establishing a causal association between RSV LRTI and RWEC/asthma, (ii) the evidence does not establish that RSV mAbs (and, by extension, future vaccines) will have a substantial effect on these outcomes and (iii) regardless of the association with long-term childhood respiratory morbidity, severe acute RSV disease in young children poses a substantial public health burden and should continue to be the primary consideration for policy-setting bodies deliberating on RSV vaccine and mAb recommendations. Nonetheless, the group recognized the public health importance of resolving this question and suggested good practice guidelines for future studies.

Rhinoviruses in infancy and risk of immunoglobulin E sensitization

Previous data about the role of viruses in the development of allergic immunoglobulin E (IgE) sensitization are contradictory. The aim of this study was to determine the possible associations between exposure to different viruses (rhinovirus, enterovirus, norovirus, and parechovirus) during the first year of life and IgE sensitization. Viruses were analyzed from stool samples collected monthly from infants participating in a prospective birth cohort study. From that study, 244 IgE sensitized case children and 244 nonsensitized control children were identified based on their allergen-specific IgE antibody levels at the age of 6, 18, and 36 months. Stool samples (n = 4576) from the case and control children were screened for the presence of rhinovirus, enterovirus, norovirus, and parechovirus RNA by reverse transcription quantitative polymerase chain reaction. The study showed that rhinovirus was the most prevalent virus detected, present in 921 (20%) samples. None of the viruses were associated with IgE sensitization in the full cohort but after stratifying by sex, the number of rhinovirus positive samples was inversely associated with IgE sensitization in boys (odds ratio [OR]: 0.81; 95% confidence interval [CI]: 0.69-0.94; P = 0.006). There was also a temporal relation between rhinoviruses and IgE sensitization, as rhinovirus exposure during the first 6 months of life was associated with a reduced risk of subsequent IgE sensitization in boys (OR: 0.76; 95% CI: 0.6-0.94; P = 0.016). In conclusion, early exposure to rhinoviruses was inversely associated with IgE sensitization but this protective association was restricted to boys.

Acute viral bronchiolitis and risk of asthma in schoolchildren: analysis of a Brazilian newborn cohort

OBJECTIVE

To verify whether the occurrence of acute viral bronchiolitis in the first year of life constitutes a risk factor for asthma at age 6 considering a parental history of asthma.

METHODS

Cross-sectional study in a cohort of live births. A standardized questionnaire of the International Study of Asthma and Allergies in Childhood was applied to the mothers to identify asthma in children at the age of 6 years. Acute viral bronchiolitis diagnosis was performed by maternal report of a medical diagnosis and/or presence of symptoms of coryza accompanied by cough, tachypnea, and dyspnea when participants were 3, 6, 9, and 12 months. Socioeconomic, environmental data, parental history of asthma, and data related to pregnancy were collected in the first 72h of life of the newborn and in prospective home visits by trained interviewers. The association between acute viral bronchiolitis and asthma was evaluated by logistic regression analysis and potential modifier effect of parental history was verified by introducing an interaction term into the adjusted logistic regression model.

RESULTS

Prevalence of acute viral bronchiolitis in the first year of life was 68.6% (461). The occurrence of acute viral bronchiolitis was a risk factor for asthma at 6 years of age in children with parental history of asthma OR: 2.66, 95% CI (1.10-6.40), modifier effect p=0.002. Parental history of asthma OR: 2.07, 95% CI (1.29-3.30) and male gender OR: 1.69, 95% CI, (1.06-2.69) were other identified risk factors for asthma.

CONCLUSION

Acute viral bronchiolitis in the first year of life is a risk factor for asthma in children with parental history of asthma.

Pediatric rhinitis risk factors

Rhinitis is a common global disorder that impacts on the quality of life of the sufferer and caregivers. Treatment for pediatric rhinitis is empirical and does not include a detailed history of the allergy triggers or allergy testing. Thus, allergen avoidance advice is not tailored to the child's sensitivities, which may result in adenoid hypertrophy. However, infant onset rhinitis, especially its relationship with respiratory viruses, remains to be further clarified. Rhinitis basically involves inflammation of the upper nasal lining, presenting typically with symptoms of runny nose (rhinorrhea), nasal blockage, and/or sneezing. While not typically fatal, it does impose significant health, psychological, and monetary burden to its sufferers, and is thus considered a global health problem. Previous findings showed that immunotherapy had significant clinical efficacy in children with allergic rhinitis. The present review article aims to highlight recent perspectives pertaining to the rhinitis risk factors especially in pediatric patients.

Increased seroprevalence of Enterovirus 71 IgE antibodies in asthmatic compared with non-asthmatic children

BACKGROUND

Asthma is a common pediatric chronic inflammatory airway disease. Respiratory viral infections are frequent infectious triggers for exacerbations of asthma.

OBJECTIVE

We sought to determine whether Enterovirus 71 (EV71), a ubiquitous virus that causes systemic inflammatory responses in children but is not a known respiratory pathogen, can also serve as an infectious trigger for asthma.

METHODS

Specific EV71 IgE and IgM antibodies (Abs), total serum IgE, and IL-2 and IL-4 cytokine levels in serum of asthmatic and non-asthmatic children (N = 42, ages 5-19; N = 35, ages 1-20, respectively) were measured (ELISA).

RESULTS

Asthmatic children had higher EV71 IgE Ab levels than non-asthmatic (P < 0.001). Non-asthmatic children had significantly higher EV71 IgM Ab levels than asthmatic (P < 0.001). Despite low serum IgE levels of non-asthmatic, compared with asthmatic (P < 0.001), the non-asthmatic children produced significantly more IL-2 and IL-4 than asthmatic (P < 0.001; P < 0.001). The ages of the asthmatics, but not the non-asthmatics had a significant effect on the levels of EV 71 IgE Abs (P = 0.02; P = 0.356). A test of difference between these two slopes was significant. However, the ages of the non-asthmatic, but not the asthmatic children had a significant effect on the levels of EV 71 IgM Abs; a test of difference between these two slopes was significant.

CONCLUSIONS

Increased specific EV71 IgE Ab responses may indicate that EV71 infection may also be an infectious trigger in asthma. However, the role of specific EV71 IgM Abs, Th2 cytokines, and age in non-asthmatic children should be further studied.

Postnatal Infections and Immunology Affecting Chronic Lung Disease of Prematurity

Premature infants suffer significant respiratory morbidity during infancy with long-term negative consequences on health, quality of life, and health care costs. Enhanced susceptibility to a variety of infections and inflammation play a large role in early and prolonged lung disease following premature birth, although the mechanisms of susceptibility and immune dysregulation are active areas of research. This article reviews aspects of host-pathogen interactions and immune responses that are altered by preterm birth and that impact chronic respiratory morbidity in these children.

The evolution of the hygiene hypothesis: the role of early-life exposures to viruses and microbes and their relationship to asthma and allergic diseases

PURPOSE OF REVIEW

Understanding the mechanisms involved in the development of asthma and allergic diseases is expanding, due in part to sequencing advances that have led to the identification of new viral strains such as human rhinovirus strain C (HRV-C) and the human microbiome project.

RECENT FINDINGS

Recent studies have identified new ways in which viral and microbial exposures in early life interact with host genetic background/variants to modify the risk for developing asthma and allergic diseases. Recent research suggests that HRV-C is the main pathogenic agent associated with infant wheeze, hospitalizations and likely the subsequent development of asthma. Pulmonary He MRI suggests that HRV infection in early childhood and subsequent immune responses initiate airway remodeling. Numerous studies of the microbiome indicate that intestinal and airway microbiome diversity and composition contribute to the cause of asthma and allergic diseases.

SUMMARY

Susceptibility to asthma and allergic diseases is complex and involves genetic variants and environmental exposures (bacteria, viruses, smoking, and pet ownership), alteration of our microbiome and potentially large-scale manipulation of the environment over the past century.

Recurrent wheeze and cough in young children: is it asthma?

A clinical diagnosis of asthma is often considered when a child presents with recurrent cough, wheeze and breathlessness. However, there are many other causes of wheeze in a young child. These range from recurrent viral infections to chronic suppurative lung disease, gastro-oesophageal reflux disease and rare structural abnormalities. Arriving at a diagnosis includes taking into consideration the symptomatology, triggers, atopic features, family history, absence of red flags and therapeutic trial, where indicated.

Infectious pathogens and bronchiolitis outcomes

Bronchiolitis is a common early childhood illness and an important cause of morbidity, it is the number one cause of hospitalization among US infants. Bronchiolitis is also an active area of research, and recent studies have advanced our understanding of this illness. Although it has long been the conventional wisdom that the infectious etiology of bronchiolitis does not affect outcomes, a growing number of studies have linked specific pathogens of bronchiolitis (e.g., rhinovirus) to short- and long-term outcomes, such as future risk of developing asthma. The authors review the advent of molecular diagnostic techniques that have demonstrated diverse pathogens in bronchiolitis, and they review recent studies on the complex link between infectious pathogens of bronchiolitis and the development of childhood asthma.

[Day-care centers: Sites of viral contact]

La répétition des épisodes infectieux chez les nourrissons placés précocement en collectivités est une évidence. Leur tropisme sur la sphère respiratoire et l’appareil digestif l’est également. Leur probable retentissement au long cours est difficile à évaluer par la rareté des études prospectives. Le risque infectieux est lié en partie au type de structure de garde, ce risque est important dans les premiers mois de fréquentation et conditionne les récidives ultérieures. Les liens de causalité entre infection virale et asthme sont complexes. Les infections virales augmentent le risque d’asthme mais le statut asthmatique augmente aussi le risque de réponses sévères à une infection virale. Alors que les infections acquises dans cet environnement sont majoritairement virales, leur répétition conduit à une utilisation excessive des antibiotiques d’où une pression de sélection microbienne et un retentissement sur le microbiome digestif voire respiratoire.

Rhinovirus has the unique ability to directly activate human T cells in vitro

BACKGROUND

Rhinovirus infection is a leading cause of exacerbation of airway diseases. We hypothesize that airway viruses activate inflammatory cells, inducing airway dysfunction. We have previously shown that airway viruses can induce eosinophil degranulation when cocultured with T cells and monocyte-derived dendritic cells (moDCs). These findings suggested that antigen presentation was important for T-cell activation.

OBJECTIVE

Given the clinical importance of rhinovirus, we sought to determine whether it had any unique abilities to activate inflammatory cells compared with another common virus, such as respiratory syncytial virus (RSV).

METHODS

We cocultured combinations of human leukocytes (T cells, moDCs, and eosinophils) with each virus. Using assays of BrdU incorporation, flow cytometry, and ELISA, we measured T-cell activation, rhinovirus expression, T-cell death, and eosinophil cysteinyl leukotriene release.

RESULTS

In contrast to RSV, rhinovirus induced T-cell activation without the involvement of moDCs. Without moDCs, rhinovirus induced T-cell proliferation of both CD4 and CD8(+) cells, cytokine production, and ultimately, eosinophil stimulation. Although chloroquine inhibited RSV-induced activation of T cells through moDCs, rhinovirus was not inhibited; UV inactivation did block the rhinovirus effect. We also found that T cells could be infected by rhinovirus in vitro and within human nasal explant tissue. Although Toll-like receptors did not appear to be involved in T-cell activation, antagonists of Jun N-terminal kinase and nuclear factor κB did inhibit T-cell responses to rhinovirus.

CONCLUSION

Rhinovirus has the unique ability to bypass antigen presentation and directly infect and activate human T cells. This could explain the strong association of rhinovirus with exacerbation of airway diseases.

Host and Viral Factors in Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is a major worldwide pathogen for which there is still no effective vaccine or antiviral treatment available, and immunoprophylaxis with RSV-specific antibodies (e.g., palivizumab) is used in limited clinical settings. In this review, we discuss virus-host interactions relevant to RSV pathobiology and how advances in cell and systems biology have accelerated knowledge in this area. We also highlight recent advances in understanding the relationship between RSV bronchiolitis and sequelae of recurrent wheezing and asthma, new findings into an intriguing interaction between RSV and air pollution, and exciting developments toward the goal of realizing a safe and effective RSV vaccine.

Role of viruses in the development of atopic disease in pediatric patients

The prevalence of atopic diseases continues to rise in modernized countries, without a clear explanation for this increase. One potential cause identified from epidemiologic studies of children is respiratory RNA viral infections leading to development of recurrent wheezing, asthma, and allergic sensitization. We review human epidemiologic data that both support and refute the role of viruses in this process. Exploring recent murine models, we document possible immunologic mechanisms that could translate a viral infection into atopic disease. We further discuss evidence for a post-viral "atopic cycle" that could explain the development of multiple allergen sensitization, and we explore available data to suggest a connection between viral infections of the gastrointestinal tract with the development of food allergy. Taken together, this review documents evidence to support the "viral hypothesis", and, in particular, the role of RNA viruses in the development of atopic disease.

Functional genetic variation in NFKBIA and susceptibility to childhood asthma, bronchiolitis, and bronchopulmonary dysplasia

Respiratory diseases are the most frequent chronic illnesses in babies and children. Although a vigorous innate immune system is critical for maintaining lung health, a balanced response is essential to minimize damaging inflammation. We investigated the functional and clinical impact of human genetic variants in the promoter of NFKBIA, which encodes IκBα, the major negative regulator of NF-κB. In this study, we quantified the functional impact of NFKBIA promoter polymorphisms (rs3138053, rs2233406, and rs2233409) on promoter-driven protein expression, allele-specific and total NFKBIA mRNA expression, IκBα protein expression, and TLR responsiveness; mapped innate immune regulatory networks active during respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia; and genotyped and analyzed independent cohorts of children with respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Genetic variants in the promoter of NFKBIA influenced NFKBIA gene expression, IκBα protein expression, and TLR-mediated inflammatory responses. Using a systems biology approach, we demonstrated that NFKBIA/IκBα is a central hub in transcriptional responses of prevalent childhood lung diseases, including respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Finally, by examining independent pediatric lung disease cohorts, we established that this immunologically relevant genetic variation in the promoter of NFKBIA is associated with differential susceptibility to severe bronchiolitis following infection with respiratory syncytial virus, airway hyperresponsiveness, and severe bronchopulmonary dysplasia. These data highlight the importance of negative innate immune regulators, such as NFKBIA, in pediatric lung disease and begin to unravel common aspects in the genetic predisposition to bronchopulmonary dysplasia, bronchiolitis, and childhood asthma.

Associations and interactions of genetic polymorphisms in innate immunity genes with early viral infections and susceptibility to asthma and asthma-related phenotypes

BACKGROUND

The innate immune system is essential for host survival because of its ability to recognize invading pathogens and mount defensive responses.

OBJECTIVES

We sought to identify genetic associations of innate immunity genes with atopy and asthma and interactions with early viral infections (first 12 months of life) in a high-risk birth cohort.

METHODS

Three Canadian family-based studies and 1 Australian population-based case-control study (n = 5565) were used to investigate associations of 321 single nucleotide polymorphisms (SNPs) in 26 innate immunity genes with atopy, asthma, atopic asthma, and airway hyperresponsiveness. Interactions between innate immunity genes and early viral exposure to 3 common viruses (parainfluenza, respiratory syncytial virus, and picornavirus) were examined in the Canadian Asthma Primary Prevention Study by using both an affected-only family-based transmission disequilibrium test and case-control methods.

RESULTS

In a joint analysis of all 4 cohorts, IL-1 receptor 2 (IL1R2) and Toll-like receptor 1 (TLR1) SNPs were associated with atopy after correction for multiple comparisons. In addition, an NFKBIA SNP was associated with atopic asthma. Six SNPs (rs1519309 [TLR3], rs740044 [ILIR2], rs4543123 [TLR1], rs5741812 [LBP], rs917998 [IL18RAP], and rs3136641 [NFKBIB]) were significant (P < .05, confirmed with 30,000 permutations) in both the combined analysis of main genetic effects and SNP-virus interaction analyses in both case-control and family-based methods. The TLR1 variant (rs4543123) was associated with both multiple viruses (respiratory syncytial virus and parainfluenza virus) and multiple phenotypes.

CONCLUSION

We have identified novel susceptibility genes for asthma and related traits and interactions between these genes and early-life viral infections.

RSV hospitalisation and healthcare utilisation in moderately prematurely born infants

Respiratory syncytial virus (RSV) infection is associated with chronic respiratory morbidity in infants born very prematurely. Our aims were to determine if infants born moderately prematurely (32--35 weeks of gestation) who had had an RSV hospitalisation, compared to those who had not, had greater healthcare utilisation and related cost of care in the first 2 years. Two thousand and sixty-six eligible infants' records were examined to identify three groups: 20 infants admitted for an RSV lower respiratory tract infection (RSV), 30 admitted for another respiratory problem (other respiratory) and 108 admitted for a nonrespiratory problem/never admitted (non-respiratory).Healthcare utilisation was assessed by examining hospital and general practitioner records and cost of care calculated using the National Scheme of Reference costs and the British National Formulary prices. The mean cost of care in the RSV group (£12,505) was greater than the non-respiratory(£1,178) (95% CI for difference £5,015 to £17,639, p=00.002) and the other respiratory (£3,356) groups (95% CI for difference £2,963 to £15,606, p<0.001). The adjusted mean differences in the cost of care were £11,186 between the RSV and non-respiratory groups (95% CI £4,763 to £17,609) and £9,076 (95% CI £2,515 to £15,637) between the RSV and the other respiratory groups. Forty-two of 2,066 eligible infants had an RSV hospitalisation (2%);thus, assuming prophylaxis would reduce the hospitalisation rate by 50%, the number needed to treat was 98. In conclusion,RSV hospitalisation in moderately prematurely born infants is associated with increased health-related cost of care. Nevertheless, if RSV prophylaxis is to be cost effective,a high risk group of moderately prematurely born infants needs to be identified.

Rhinitis in children less than 6 years of age: current knowledge and challenges

Rhinitis is a disease of the upper airway characterized by runny and/or blocked nose and/or sneezing. Though not viewed as a life threatening condition, it is also recognized to impose significant burden to the quality of life of sufferers and their caretakers and imposes an economic cost to society. Through a PubMed online search of the literature from 2006 to September 2011, this paper aims to review the published literature on rhinitis in young children below the age of 6 years. It is apparent from epidemiology studies that rhinitis in this age group is a relatively common problem. The condition has a heterogenous etiology with classification into allergic and non-allergic rhinitis. Respiratory viral infections may play a role in the pathogenesis of long standing rhinitis, but definitive studies are still lacking. Treatment guidelines for management are lacking for this age group, and is a significant unmet need. Although the consensus is that co-morbidities including otitis media with effusion, adenoidal hypertrophy and asthma, are important considerations of management of these children. Pharmacotherapy is limited for young children especially for those below the age of 2 years. This review underscores the lack of understanding of rhinitis in early childhood and therefore the need for further research in this area.

A review of palivizumab and emerging therapies for respiratory syncytial virus

INTRODUCTION

Respiratory syncytial virus (RSV) is an important pathogen in children and adults; however, current treatment options are primarily supportive. Palivizumab, the only approved specific monoclonal antibody for RSV is used prophylactically to reduce morbidity in a select population of high-risk children.

AREAS COVERED

The development and current use of palivizumab; the potential role of palivizumab as preventive therapy in patients with cystic fibrosis, asthma and compromised immune systems; and explores the limited research in which palivizumab has been used for treatment of RSV. The modified recommendations for the use of palivizumab espoused by the American Academy of Pediatrics and research on the cost-effectiveness of this product are presented. In addition, the authors discuss the development of enhanced monoclonal antibodies including motavizumab, which was recently denied FDA approval for preventative therapy. The authors explore the historical and current efforts to develop a vaccine targeting RSV. The current status of antiviral drug development is also reviewed. The literature search included RSV-Ig, palivizumab, and emerging drugs and vaccines for the treatment of RSV as keywords and titles from 1997 to 2011.

EXPERT OPINION

Although there are potential drugs and vaccines in development to prevent or reduce the effects of RSV infection, palivizumab remains the only licensed product to reduce the severity of disease in high-risk pediatric patients.

Viruses and asthma

Background

Viral respiratory infection has long been known to influence the occurrence of asthma exacerbations. Over the last 20 years much effort has been put into clarifying the role that viral respiratory infections play in the eventual development of asthma.

Scope of review

In this review we give a general background of the role of viruses in the processes of asthma exacerbation and asthma induction. We review recent additions to the literature in the last 3 years with particular focus on clinical and epidemiologic investigations of influenza, rhinovirus, bocavirus, respiratory syncytial virus, and metapneumovirus.

Major conclusions

The development of asthma emerges from a complex interaction of genetic predisposition and environmental factors with viral infection likely playing a significant role in the effect of environment on asthma inception. This article is part of a Special Issue entitled: Biochemistry of Asthma.

General significance

Further understanding of the role that viruses play in asthma exacerbation and inception will contribute to decreased asthma morbidity in the future. This article is part of a Special Issue entitled: Biochemistry of Asthma.

Global strategy for the diagnosis and management of asthma in children 5 years and younger

Asthma is the most common chronic disease of childhood and the leading cause of childhood morbidity from chronic disease as measured by school absences, emergency department visits, and hospitalisation. During the past two decades, many scientific advances have improved our understanding of asthma and our ability to manage and control it effectively. However, in children 5 years and younger, the clinical symptoms of asthma are variable and non-specific. Furthermore, neither airflow limitation nor airway inflammation, the main pathologic hallmarks of the condition, can be assessed routinely in this age group. For this reason, to aid in the diagnosis of asthma in young children, a symptoms-only descriptive approach that includes the definition of various wheezing phenotypes has been recommended. In 1993, the Global Initiative for Asthma (GINA) was implemented to develop a network of individuals, organizations, and public health officials to disseminate information about the care of patients with asthma while at the same time assuring a mechanism to incorporate the results of scientific investigations into asthma care. Since then, GINA has developed and regularly revised a Global Strategy for Asthma Management and Prevention. Publications based on the Global Strategy for Asthma Management and Prevention have been translated into many different languages to promote international collaboration and dissemination of information. In this report, Global Strategy for Asthma Management and Prevention in Children 5 Years and Younger, an effort has been made to present the special challenges that must be taken into account in managing asthma in children during the first 5 years of life, including difficulties with diagnosis, the efficacy and safety of drugs and drug delivery systems, and the lack of data on new therapies. Approaches to these issues will vary among populations in the world based on socioeconomic conditions, genetic diversity, cultural beliefs, and differences in healthcare access and delivery. Patients in this age group are often managed by pediatricians and general practitioners routinely faced with a wide variety of issues related to childhood diseases.

Moving towards a new generation of animal models for asthma and COPD with improved clinical relevance

Asthma and chronic obstructive pulmonary disease (COPD) are complex inflammatory airway diseases characterised by airflow obstruction that remain leading causes of hospitalization and death worldwide. Animal modelling systems that accurately reflect disease pathophysiology continue to be essential to the development of new therapies for both conditions. In this review, we describe preclinical in vivo models that recapitulate many of the features of asthma and COPD. Specifically, we discuss the pro's and con's of the standard models and highlight recently developed systems designed to more accurately reflect the complexity of both diseases. For instance, clinically relevant allergens (i.e. house dust mite) are now being used to mimic the inflammatory changes and airway remodelling that result after chronic allergen exposures. Additionally, systems are being developed to mimic steroid-resistant and viral exacerbations of allergic inflammation - aspects of asthma where there is an acute need for new therapies. Similarly, COPD models have evolved to align with the improved clinical understanding of the factors contributing to disease progression. This includes using cigarette smoke to model not only airway inflammation and remodelling, but some systemic changes (e.g. hypertension and skeletal muscle alterations) that are thought to influence disease. Further, mouse genetics are being exploited to gain insights into the genetics of COPD susceptibility. The new models of asthma and COPD described herein demonstrate that improved clinical understanding of the diseases and better preclinical models is an iterative process that will hopefully lead to therapies that can effectively manage severe asthma and COPD.

The effect of respiratory syncytial virus on subsequent recurrent wheezing in atopic and nonatopic children

BACKGROUND

Although respiratory syncytial virus (RSV) lower respiratory tract infections (LRTIs) in early life are followed by later airway hyperreactivity, it is unclear whether there is a causal relationship between this and an atopic diathesis.

OBJECTIVES

To separate the effects of RSV LRTI and an atopic diathesis on subsequent recurrent wheezing, we examined the protective effect of previous palivizumab administration against subsequent recurrent wheeze in infants with and without a family history of atopy.

METHODS

A prospective multicenter, matched, double cohort study was conducted in 27 centers in Europe and Canada. The rates of physician-diagnosed recurrent wheezing in premature infants <36 weeks gestation who had received palivizumab in the first year of life were compared to those of gestational age-matched controls.

RESULTS

The relative protective effect of palivizumab on physician-diagnosed recurrent wheezing through the ages of 2 to 5 years was 68% in those with no family history of asthma (odds ratio, 0.32; (95% CI, 0.14-0.75; N = 146 palivizumab-treated, 171 untreated) and 80% in those with no family history of atopy or food allergies (odds ratio, 0.20; 95% CI, 0.07-0.59; N = 101 palivizumab-treated, 100 untreated). In contrast, there was no effect of palivizumab on subsequent recurrent wheezing in the 90 children with a family history of atopy or food allergies compared to 130 untreated infants with atopic families.

CONCLUSION

Respiratory syncytial virus prophylaxis in nonatopic children decreases by 80% the relative risk of recurrent wheezing but does not have any effect in infants with an atopic family history. This suggests that RSV predisposes to recurrent wheezing in an atopy-independent mechanism.

The role of viruses in the development and exacerbation of atopic disease

Objective

To examine data in support of the viral hypothesis of atopic disease.

Data Sources

We retrieved review articles and original research from MEDLINE, OVID, and PubMed (1950-June 2009) that addressed our topic of interest, using the terms respiratory virus, asthma, IgE, atopy, and viral-induced wheeze.

Study Selection

Articles were selected for their relevance to viruses and their role in asthma.

Results

Much of the data in support of the viral role in asthma focuses on rhinovirus and respiratory syncytial virus. Epidemiologic studies have used factors such as day-care and family size as surrogates for infection in studies that support and negate the role of viruses in the development of asthma. A large volume of literature supports the theory that virus exacerbates preexisting asthma by setting off the inflammatory cascade. No mechanistic studies fully explain how viral infections can translate or exacerbate atopic disease. We provide information from our mouse model that suggests that dendritic cells, IgE, and FcɛRI are critical to the induction of atopy. Studies of patients taking antiviral agents (eg, ribavirin or palvizumab) support the notion that interfering with respiratory viral infections may decrease the development of atopy.

Conclusions

Many studies suggest strongly that viral infections may predispose patients to the development of asthma and other atopic diseases. Further, mechanistic studies are necessary to allow for the development of targeted therapeutics to prevent the translation of viral into atopic disease.

The interaction between early life upper respiratory tract infection and birth during the pollen season on rye-sensitized hay fever and ryegrass sensitization--a birth cohort study

Studies on early life viral respiratory infection and subsequent atopic disease in childhood have conflicting findings. Animal models show that viral respiratory infection in conjunction with allergen presentation can enhance sensitization. This prospective study assesses the influence of an upper respiratory tract infection (URI) in the first month of life and the season of birth on the development of hay fever and ryegrass allergen sensitization in childhood. From a Tasmanian cohort born during 1988 and 1989, a group of 498 children were followed up at 8 yr and another different group of 415 children were followed up at 16 yr. The ryegrass pollen season in Tasmania occurs in November and December. Forty-four (9.6%) children in Follow-up sample 1 and 47 (12.5%) children in Follow-up sample 2 were born in the pollen season. The parental report of an early upper respiratory tract infection (EURI) was documented prospectively by a home interview at 1 month of age (median age 5.1 wk). Sensitization to ryegrass and house dust mite (HDM) was determined at 8 yr of age by skin prick testing and at 16 yr by ImmunoCap. Ryegrass sensitized hay fever was defined as a positive response to a question on hay fever plus the presence of ryegrass allergy. For children tested at age 8 and born in the pollen season, a EURI by postnatal interview was associated with an increased risk of ryegrass sensitization (OR 5.80 95% CI 1.07, 31.31) but not for children with a EURI born outside the pollen season (OR 0.62 95% CI 0.35, 1.08). Similarly, EURI was significantly associated with early onset (< or = 8 yr) ryegrass sensitized hay fever for children born in the pollen season (AOR 4.78 95% CI 1.17, 19.47) but was not associated with early onset ryegrass sensitized hay fever for children born outside the pollen season (AOR 0.76 95% CI 0.43, 1.33). These findings suggest that early life viral URI interacts with ryegrass allergen exposure in the development of ryegrass allergen sensitization and ryegrass sensitized hay fever symptoms.

[Virus and sensitization]

Les virus respiratoires peuvent, en se répliquant aussi bien au niveau de l’épithélium respiratoire supérieur qu’inférieur, induire des sifflements. La plupart des études cliniques soulignent qu’une symptomatologie sifflante secondaire à l’atteinte par un virus respiratoire durant la prime enfance est liée à un risque ultérieur d’asthme. Les virus peuvent induire une exacerbation asthmatique par un effet direct sur sa cible principale, l’épithélium, mais aussi d’une réaction immuno-inflammatoire médiée par voie systémique. Par ailleurs, des études ont également montré des résultats discordants dans la capacité d’une infection virale d’induire des réponses allergiques significatives. Est-ce le virus l’initiateur de l’asthme allergique ou les sifflements viro-induits le révélateur d’enfants déjà prédisposés à l’atopie en raison d’anomalies préexistantes pulmonaires et/ou de la réponse immunitaire ?

Role of respiratory viral infections in the development of atopic conditions

PURPOSE OF REVIEW

Respiratory viral infections are implicated in both protection from, and inception of, allergic airway disease. Severe lower respiratory tract viral infections are associated with recurrent wheeze, asthma and atopy. It is unclear if this association is causal and the underlying mechanisms governing this are unknown. Whilst respiratory viral infections are the major precipitants of acute exacerbations of wheezing illness, early life infections are also clearly associated with protection from allergic diseases. This article aims to review the current understanding of the complex relationship between lower respiratory tract viral infections and their impact upon development of atopy in the airway.

RECENT FINDINGS

Clinical studies and animal models have further demonstrated that lower respiratory tract viral infections are strongly associated with development of recurrent wheeze and asthma with human rhinoviruses being shown to be the most prevalent cause of lower respiratory tract viral infections in infants, along with associated asthma development. A case-control study provided evidence of a contributory role for respiratory viral infections within this association, whilst recent experimental studies provide a possible mechanistic insight.

SUMMARY

Progress into understanding the relationship between respiratory viral infections and allergic airway disease is essential for development of treatments aimed at treating common risk factors mediating association but not cause. Recent findings may have begun to identify key pathways open to therapeutic intervention.

Host immune responses to rhinovirus: mechanisms in asthma

Viral respiratory infections can have a profound effect on many aspects of asthma including its inception, exacerbations, and, possibly, severity. Of the many viral respiratory infections that influence asthma, the common cold virus, rhinovirus, has emerged as the most frequent illness associated with exacerbations and other aspects of asthma. The mechanisms by which rhinovirus influences asthma are not fully established, but current evidence indicates that the immune response to this virus is critical in this process. Many airway cell types are involved in the immune response to rhinovirus, but most important are respiratory epithelial cells and possibly macrophages. Infection of epithelial cells generates a variety of proinflammatory mediators to attract inflammatory cells to the airway with a subsequent worsening of underlying disease. Furthermore, there is evidence that the epithelial airway antiviral response to rhinovirus may be defective in asthma. Therefore, understanding the immune response to rhinovirus is a key step in defining mechanisms of asthma, exacerbations, and, perhaps most importantly, improved treatment.

Predictors of wheezing in prematurely born children

OBJECTIVE

To examine the degree to which neonatal illness severity, postneonatal health problems, child characteristics, parenting quality as measured by the HOME Inventory, and maternal characteristics are related to the development of wheezing in prematurely born children over the first 27 months after term.

DESIGN

Longitudinal predictive study.

SETTING

Infants were recruited from two neonatal intensive care units, one in southeast and one in Midwest.

PARTICIPANTS

One hundred thirteen preterm infants who weighed less than 1,500 g or required mechanical ventilation and their mothers.

MAIN OUTCOME MEASURES

The presence of wheezing was obtained from maternal report at 2, 6, 9, 13, 18, 22, and 27 months. Wheezing was considered to be medically significant if the child was using bronchodilators or pulmonary antiinflammatory medications.

RESULTS

Sixty-eight percent of the children had wheezing at least one or more ages; 47% of the children were also taking bronchodilators or pulmonary antiinflammatory medications and thus had medically significant wheezing.

CONCLUSION

Postneonatal health problems and the social environment appear to be more important in developing wheezing in prematurely born children than neonatal medical complications.

Early environmental determinants of asthma risk in a high-risk birth cohort

Environmental exposures during early life have been suggested to have the greatest impact on childhood asthma. Our aim was to evaluate the risk factors associated with asthma at age 7 yr in a high-risk cohort that participated in a randomized controlled study on the primary prevention of asthma. Indoor exposures were characterized before birth and at 2 weeks, 4, 8, 12, 18, and 24 months after birth and again at 7 yr. Nasal scrapings for respiratory viruses were done at the same intervals during the first 2 yr. At age 7, the children were assessed by a pediatric allergist and had allergy skin tests. Logistic regression analysis was undertaken to evaluate the effect of exposures on asthma for the entire cohort with adjustment for group allocation. In addition to the lower risk of asthma in the intervention group, we found a higher prevalence of asthma at age 7 for males, those having a positive history of asthma in mother, father, or older siblings, for children residing in Winnipeg and for atopic subjects. Upon adjustment for intervention group assignment and baseline factors, significant environmental risk factors during year 1 included dog ownership and respiratory syncytial viral infection detected at 12 months while maternal smoking was protective. Dog ownership was a significant risk factor in year 2, but highly correlated with dog ownership in year 1. Indoor environmental exposures during year 7 were not associated with asthma at age 7. Maternal smoking at year 7 was associated with a reduced risk of asthma at 7 yr. Early-life exposures were more important determinants than those in later years. A 'window of opportunity' exists for intervention measures to be applied.

Early respiratory infections and asthma among New York City Head Start children

BACKGROUND

Respiratory infections in neonates have been found to predict wheeze among young children. We hypothesized that among preschool children from low-income minority communities in New York City, current asthma would be associated with a history of respiratory infection in the first few months after their birth.

METHODS

We asked parents of children in New York City Head Start centers (preschool programs for children of low-income families) to respond to a questionnaire covering demographic factors, lifestyle, home environment, and health history, including a detailed history of respiratory conditions. We used logistic regression to model the association of asthma and asthma severity with history of respiratory infections, controlling for gender, ethnicity, family history of asthma, and other factors.

RESULTS

Among 1,022 children (mean age 4+/- 0.6 years) whose parents provided information about their health history, 359 (35%) met our criteria for asthma. Overall, 22% had had a cold by 6 months and 17% an ear infection by 8 months of age. In multivariable models, children with asthma had had more colds (OR = 2.8, 95% confidence interval [CI] 1.4-6.0) and ear infections (OR = 3.4, 95% CI 1.7-6.9) in the past year than other children. Associations of respiratory infections with emergency department use for asthma (as a measure of severity) were similar. In models that did not control for infections in the past year, ages at first cold and first ear infection were associated with asthma and emergency department visits in the past year.

CONCLUSIONS

In this sample of preschool children, respiratory infections were common and were associated with asthma and health care utilization for asthma exacerbations. If these findings are confirmed, preventive measures among children who develop such infections at a very early age should be explored to help reduce the burden of asthma in this age group.

Understanding the mechanisms of viral induced asthma: new therapeutic directions

Asthma is a common and debilitating disease that has substantially increased in prevalence in Western Societies in the last 2 decades. Respiratory tract infections by respiratory syncytial virus (RSV) and rhinovirus (RV) are widely implicated as common causes of the induction and exacerbation of asthma. These infections in early life are associated with the induction of wheeze that may progress to the development of asthma. Infections may also promote airway inflammation and enhance T helper type 2 lymphocyte (Th2 cell) responses that result in exacerbations of established asthma. The mechanisms of how RSV and RV induce and exacerbate asthma are currently being elucidated by clinical studies, in vitro work with human cells and animal models of disease. This research has led to many potential therapeutic strategies and, although none are yet part of clinical practise, they show much promise for the prevention and treatment of viral disease and subsequent asthma.

Prospective multicenter study of the viral etiology of bronchiolitis in the emergency department

Objectives:  To determine the viral etiology of bronchiolitis and clinical characteristics of children age < 2 years presenting to the emergency department (ED) with bronchiolitis.

Methods:  The authors conducted a 14‐center prospective cohort study during 2005–2006 of ED patients age < 2 years with bronchiolitis. The study was conducted in 10 states as part of the Emergency Medicine Network. Researchers collected nasopharyngeal aspirates and conducted structured interviews, medical record reviews, and 2‐week follow‐up telephone calls. Samples were tested using reverse transcription polymerase chain reaction for respiratory syncytial virus (RSV), rhinovirus (RV), human metapneumovirus (hMPV), and influenza viruses (Flu).

Results:  Testing of 277 samples revealed 176 (64%) positive for RSV, 44 (16%) for RV, 26 (9%) for hMPV, 17 (6%) for Flu A, and none for Flu B. When children were categorized as RSV only, RV only, RV and RSV, and all others (hMPV, Flu, no identified virus), children with RV only were more likely to be African American (19, 62, 14, and 40%, respectively; p < 0.001) and have a history of wheezing (23, 52, 21, and 15%, respectively; p = 0.01). In multivariate models, children with RV were more likely to receive corticosteroids (odds ratio [OR] 3.5; 95% confidence interval [CI] = 1.5 to 8.15). The duration of illness may be shorter for children with RV (Days 8, 3, 6, and 8; p = 0.07).

Conclusions:  In this multicenter study, RSV was the most frequent cause of bronchiolitis (64%). RV was present in 16%, and these children have a distinct profile in terms of demographics, medical history, and ED treatment.