Community study of role of viral infections in exacerbations of asthma in 9-11 year old children

Alpha-1-antitrypsin and complement component C7 are involved in asthma exacerbation

Asthma is the most common chronic disorder in childhood and asthma exacerbation is an important cause of childhood morbidity and hospitalization. Allergic responses are known to be biased toward T-helper type 2 in asthmatics; however, the pathogenesis of asthma is not simple, and our understanding of the disease mechanism remains incomplete. The aim of the present study was to identify protein expression signatures that reflect acute exacerbation of asthma. Plasma was taken twice from pediatric asthmatic patients, once during asthma exacerbation and once during a stable period. Plasma was also taken from healthy children as a control. The protein profiles of plasma during asthma exacerbation were analyzed by 2-DE and 49 spots were differentially expressed during asthma exacerbation. Thirty-eight of the spots were successfully identified by MALDI-TOF MS. Proteins up- or down-regulated during asthma exacerbation were involved in responses to stress and pathogens, in the complement and coagulation cascades, and in acute-phase responses. Among the differentially expressed proteins, up-regulation of alpha-1-antitrypsin and complement component C7 was confirmed by nephelometry and ELISA. Our present results suggest that protease inhibitors and complement components may be involved in asthma exacerbation, and plasma level of alpha-1-antitrypsin may be a potential biomarker for asthma.

Many asthma patients experience persistent symptoms despite appropriate clinical and guideline-based treatment with inhaled corticosteroids

PURPOSE

To review possible reasons for persistence of asthma symptoms despite appropriate use of clinical and guideline-based treatments, including the use of inhaled corticosteroids.

DATA SOURCES

Review of the worldwide scientific literature on factors related to persistent symptoms in patients with asthma.

CONCLUSIONS

Patients with asthma may not respond as expected to therapy because of factors that include poor adherence, improper inhaler technique, persistent exposure to symptom triggers, and limitations of current standard therapy, including steroid insensitivity or the steroid plateau effect. Persistent symptoms may also be associated with IgE-mediated airway inflammation, as current standard asthma therapies do not directly address the IgE-mediated component of the inflammatory cascade. Asthma is a complex disease and its treatment requires the full cooperation and participation of the patient.

IMPLICATIONS FOR PRACTICE

Healthcare professionals can play a key role by educating patients and their family members about the nature of asthma and rationale for treatment, supporting the importance of strict adherence to prevention measures and the prescribed treatment regimen.

Respiratory syncytial virus decreases p53 protein to prolong survival of airway epithelial cells

Respiratory syncytial virus (RSV) is a clinically important pathogen. It preferentially infects airway epithelial cells causing bronchiolitis in infants, exacerbations in patients with obstructive lung disease, and life-threatening pneumonia in the immunosuppressed. The p53 protein is a tumor suppressor protein that promotes apoptosis and is tightly regulated for optimal cell growth and survival. A critical negative regulator of p53 is murine double minute 2 (Mdm2), an E3 ubiquitin ligase that targets p53 for proteasome degradation. Mdm2 is activated by phospho-Akt, and we previously showed that RSV activates Akt and delays apoptosis in primary human airway epithelial cells. In this study, we explore further the mechanism by which RSV regulates p53 to delay apoptosis but paradoxically enhance inflammation. We found that RSV activates Mdm2 1-6 h after infection resulting in a decrease in p53 6-24 h after infection. The p53 down-regulation correlates with increased airway epithelial cell longevity. Importantly, inhibition of the PI3K/Akt pathway blocks the activation of Mdm2 by RSV and preserves the p53 response. The effects of RSV infection are antagonized by Nutlin-3, a specific chemical inhibitor that prevents the Mdm2/p53 association. Nutlin-3 treatment increases endogenous p53 expression in RSV infected cells, causing earlier cell death. This same increase in p53 enhances viral replication and limits the inflammatory response as measured by IL-6 protein. These findings reveal that RSV decreases p53 by enhancing Akt/Mdm2-mediated p53 degradation, thereby delaying apoptosis and prolonging survival of airway epithelial cells.

Chlamydophila pneumoniae induces a sustained airway hyperresponsiveness and inflammation in mice

Background

It has been reported that Chlamydophila (C.) pneumoniae is involved in the initiation and promotion of asthma and chronic obstructive pulmonary diseases (COPD). Surprisingly, the effect of C. pneumoniae on airway function has never been investigated.

Methods

In this study, mice were inoculated intranasally with C. pneumoniae (strain AR39) on day 0 and experiments were performed on day 2, 7, 14 and 21.

Results

We found that from day 7, C. pneumoniae infection causes both a sustained airway hyperresponsiveness and an inflammation. Interferon-γ (IFN-γ) and macrophage inflammatory chemokine-2 (MIP-2) levels in bronchoalveolar lavage (BAL)-fluid were increased on all experimental days with exception of day 7 where MIP-2 concentrations dropped to control levels. In contrast, tumor necrosis factor-α (TNF-α) levels were only increased on day 7. From day 7 to 21 epithelial damage and secretory cell hypertrophy was observed. It is suggested that, the inflammatory cells/mediators, the epithelial damage and secretory cell hypertrophy contribute to initiation of airway hyperresponsiveness.

Conclusion

Our study demonstrates for the first time that C. pneumoniae infection can modify bronchial responsiveness. This has clinical implications, since additional changes in airway responsiveness and inflammation-status induced by this bacterium may worsen and/or provoke breathlessness in asthma and COPD.

Rhinovirus infection in hospitalized children in Hong Kong: a prospective study

OBJECTIVES

To analyze the clinical features and estimate the hospitalization disease burden of rhinovirus infection in children in Hong Kong.

METHODS

In this prospective study, nasopharyngeal aspirates were taken from children aged <18 years with symptoms of acute respiratory infection admitted to Queen Mary Hospital on one fixed day of the week during August 2001-July 2002 for detection of common respiratory viruses by immunofluorescence, viral culture, and for rhinovirus, human metapneumovirus, and coronaviruses by reverse transcription polymerase chain reaction. The clinical features of rhinovirus infections were analyzed and hospitalization disease burden was estimated.

RESULTS

Altogether 239 of the 426 nasopharyngeal aspirates (56.1%) were positive for respiratory viruses, including 151 patients with rhinovirus (35.4%). The median age was 2.34 years. Upper respiratory infection, asthma exacerbation, pneumonia, and acute bronchiolitis were diagnosed in 44.4%, 19.9%, 11.3%, and 7.9%, respectively. The most common symptoms were cough (81.5%), runny nose (76.8%), and fever (68.9%). Shortness of breath, wheezes, and crepitation were present in 25.8%, 29.1%, and 18.5%, respectively. Fifty-five of 99 patients (55.6%) had chest radiographic abnormalities, most commonly perihilar streakiness. Children with chronic diseases were more likely to have lower respiratory tract infection and these children required longer hospitalization (mean 0.6 days longer). Coinfection with other respiratory pathogens was common (33.1%).

CONCLUSION

Rhinovirus is frequently associated with asthmatic exacerbations and lower respiratory tract infection, especially in children with chronic diseases and is potentially an important contributor to hospitalization in children in Hong Kong.

Role of rhinovirus in hospitalized infants with respiratory tract infections in Spain

BACKGROUND

Rhinovirus is a recognized cause of common cold, proven to cause asthma exacerbations in children. In Spain, no description exists, as yet, as to the degree of burden rhinovirus infections represent among hospitalized infants. Our aim was to describe rhinovirus infections in hospitalized children, under 2 years of age, and to compare these with patients infected with respiratory syncytial virus (RSV).

PATIENTS AND METHODS

The prospective study was performed between September 2003 and July 2005, in children <2 years of age, admitted at the Severo Ochoa Hospital (Leganés, Madrid) with fever or respiratory tract infection and with positive rhinovirus detection in the nasopharyngeal aspirate samples. Virologic diagnosis was made by multiplex reverse transcription-polymerase chain reaction and for some virus by direct immunofluorescent assay in nasopharyngeal samples. Demographic and clinical data of those patients with rhinovirus infection were described and compared with a group of 86 patients, infected only with RSV, randomly selected from the same population.

RESULTS

We detected 85 children admitted to hospital with rhinovirus infection. Rhinovirus was the cause of 25% of all admissions, among the total of 340 under 2-year olds diagnosed with fever or respiratory tract infection. Rhinovirus was the second viral agent identified, after RSV. Clinical diagnosis was recurrent wheezing in 48.2%; bronchiolitis in 36.5%; and pneumonia in 3.5%. Fever was present in 60% of the patients. Radiologic infiltrates were found in 22.4% of the children. In 50.6% of the infants, oxygen saturation under 95% was detected, at the time of admission. Hypoxia was present in RSV-infected children more frequently (P = 0.005). Also, in this group, final diagnosis was, most frequently, bronchiolitis (P = 0.0001), and rhinovirus-infected patients were most frequently males (P = 0.004).

CONCLUSIONS

Rhinovirus was detected in hospitalized infants with respiratory tract disease and was the second most common virus after RSV. In our experience, it was the second etiologic agent associated with recurrent wheezing in hospitalized children, under the age of 2 years.

TLR3- and Th2 cytokine-dependent production of thymic stromal lymphopoietin in human airway epithelial cells

Thymic stromal lymphopoietin (TSLP) is elevated in asthma and triggers dendritic cell-mediated activation of Th2 inflammatory responses. Although TSLP has been shown to be produced mainly by airway epithelial cells, the regulation of epithelial TSLP expression has not been extensively studied. We investigated the expression of TSLP in cytokine- or TLR ligand-treated normal human bronchial epithelial cells (NHBE). The mRNA for TSLP was significantly up-regulated by stimulation with IL-4 (5.5-fold) and IL-13 (5.3-fold), weakly up-regulated by TNF-alpha, TGF-beta, and IFN-beta, and not affected by IFN-gamma in NHBE. TSLP mRNA was only significantly up-regulated by the TLR3 ligand (dsRNA) among the TLR ligands tested (66.8-fold). TSLP was also induced by in vitro infection with rhinovirus. TSLP protein was detected after stimulation with dsRNA (120 +/- 23 pg/ml). The combination of TNF-alpha and IL-4 produced detectable levels of TSLP protein (40 +/- 13 pg/ml). In addition, TSLP was synergistically enhanced by a combination of IL-4 and dsRNA (mRNA; 207-fold, protein; 325 +/- 75 pg/ml). The induction of TSLP by dsRNA was dependent upon NF-kappaB and IFN regulatory factor 3 (IRF-3) signaling via TLR3 as indicated by a study with small interfering RNA. The potent topical glucocorticoid fluticasone propionate significantly suppressed dsRNA-dependent TSLP production in NHBE. These results suggest that the expression of TSLP is induced in airway epithelial cells by stimulation with the TLR3 ligand and Th2 cytokines and that this response is suppressed by glucocorticoid treatment. This implies that respiratory viral infection and the recruitment of Th2 cytokine producing cells may amplify Th2 inflammation via the induction of TSLP in the asthmatic airway.

[Human bocavirus infections in Spanish 0-14 year-old: clinical and epidemiological characteristics of an emerging respiratory virus]

INTRODUCTION

In 2005 a new respiratory virus, called human bocavirus (HBoV), was cloned from respiratory samples from Swedish infants and children with lower respiratory tract infections.

OBJECTIVES

To determine whether HBoV has circulated in Spain, estimate the frequency of HBoV infections in patients hospitalized for respiratory infection and describe the clinical and epidemiological characteristics of these patients.

PATIENTS AND METHODS

We performed a descriptive prospective study of confirmed HBoV infections in patients aged < 14 years old, hospitalized for respiratory infections between October 2004 and June 2005. Virologic diagnosis was based on multiple RT-PCR for respiratory syncytial virus (RSV) A and B, influenza A,B, and C, parainfluenza 1-4, adenovirus and rhinovirus; PCR was used for human metapneumovirus (hMPV) and PCR in nasopharyngeal aspirates was used for HBoV. The clinical and epidemiological characteristics of patients were analyzed.

RESULTS

Fifty-two cases of HBoV infection were detected, representing 17.1% (95% CI: 13% a 21%) of patients hospitalized for respiratory infections. HBoV was the third most frequent viral agent after RSV (30%) and rhinovirus (25%). In 39 patients (71.1%) coinfection with another respiratory virus was detected. Fifty percent of the patients were aged less than 13.6 months and 75% were aged less than 2 years. The most frequent diagnoses were recurrent wheezing (55.8%), bronchiolitis (21.2%) and pneumonia (15.4%). Clinical sepsis with petechial exanthema was found in two patients. Fever > 38 degrees C was found in 72.1% and radiological infiltrate in 44%. Hypoxia was present in 55.8 % of the patients. HBoV was isolated in distinct episodes in two patients. Coinfections were similar to simple infections except that hypoxia was more frequent in the former (p = 0.038).

CONCLUSIONS

HBoV is one of the most frequent viruses in severe respiratory infections in patients aged less than 14 years old. Only RSV and rhinovirus are more frequent. Coinfections are highly frequent. Most patients are infants with recurrent wheezing and bronchiolitis.

Clinical evaluation of leukotriene receptor antagonists in preventing common cold-like symptoms in bronchial asthma patients

BACKGROUND

We investigated the possibility of preventing common cold-like symptoms as a previously unknown benefit of leukotriene receptor antagonists (LTRAs).

METHODS

A total of 279 adult patients with bronchial asthma referred to our hospital between June and December 2004 were retrospectively analyzed. Patients were divided into LTRA treated and untreated groups. Frequency of acute exacerbations and number of visits to emergency rooms and of hospital admissions were analyzed as indicators of frequency of infections and asthma exacerbation over the previous 12 months.

RESULTS

Irrespective of inhaled corticosteroid (ICS) use, frequency of infections was significantly lower in the LTRA treated group (0.3 +/- 0.7 times/year) than in the LTRA untreated group (1.6 +/- 4.2 times/year) (P < 0.05), suggesting that LTRA therapy prevents common cold-like symptoms. Frequency of acute exacerbations and number of hospital admissions were significantly lower in the LTRA treated versus LTRA untreated group (0.4 +/- 0.8 versus 2.7 +/- 4.3 times/year and 0.0 +/- 0.2 versus 0.4 +/- 0.7 times/year, respectively; both P < 0.01). When the patients were divided into ICS treated and untreated groups, none of the parameters analyzed differed significantly between the two groups, although all parameters tended to be lower in the ICS treated group.

CONCLUSIONS

Adult asthma patients undergoing treatment with LTRAs exhibit lower incidence rates of common cold-like symptoms than those not receiving LTRAs. LTRAs play an important role in reducing the incidence of common cold-like symptoms among asthma patients and in suppressing exacerbation of asthma symptoms possibly associated with these symptoms.

Pan-viral screening of respiratory tract infections in adults with and without asthma reveals unexpected human coronavirus and human rhinovirus diversity

Background. Between 50% and 80% of asthma exacerbations are associated with viral respiratory tract infections (RTIs), yet the influence of viral pathogen diversity on asthma outcomes is poorly understood because of the limited scope and throughput of conventional viral detection methods.

Methods. We investigated the capability of the Virochip, a DNA microarray—based viral detection platform, to characterize viral diversity in RTIs in adults with and without asthma.

Results. The Virochip detected viruses in a higher proportion of samples (65%) than did culture isolation (17%) while exhibiting high concordance (98%) with and comparable sensitivity (97%) and specificity (98%) to pathogen-specific polymerase chain reaction. A similar spectrum of viruses was identified in the RTIs of each patient subgroup; however, unexpected diversity among human coronaviruses (HCoVs) and human rhinoviruses (HRVs) was revealed. All but one of the HCoVs corresponded to the newly recognized HCoV-NL63 and HCoV-HKU1 viruses, and >20 different serotypes of HRVs were detected, including a set of 5 divergent isolates that formed a distinct genetic subgroup.

Conclusions. The Virochip can detect both known and novel variants of viral pathogens present in RTIs. Given the diversity detected here, larger-scale studies will be necessary to determine whether particular substrains of viruses confer an elevated risk of asthma exacerbation.

Detection of viruses identified recently in children with acute wheezing

The etiologic role of recently identified respiratory viruses for acute wheezing in children is not yet clear. The purpose of this study was to investigate the prevalence of recently identified viruses, including human metapneumovirus (hMPV), human bocavirus (hBoV), human coronavirus NL63 (hCoV‐NL63), and human coronavirus HKU1 (hCoV‐HKU1) in children with acute wheezing. Viral etiology was identified in 231 children hospitalized with acute wheezing, aged from 1 month to 5 years. Viral antigens for common respiratory viruses were detected by IFA or multiplex PCR. RT‐PCR was used to detect respiratory rhinoviruses, hCoV‐NL63, hCoV‐HKU1, and hMPV. PCR assays for hBoV DNA were performed using the primer sets for noncapsid protein (NP1) and nonstructural protein (NS1) genes. Viruses were found in 61.5% (142/231) of the study population and a single virus was detected in 45.5% (105/231) of the study population. Rhinovirus (33.3%), human respiratory syncytial virus (hRSV; 13.8%), and hBoV (13.8%) were the most frequently detected viruses. hMPV and hCoV‐NL63 were detected in 7.8% and 1.3% of wheezing children, respectively. HCoV‐HKU1 was not detected. In 16.0% of the study population, more than one virus was detected. In children with acute wheezing, rhinovirus, hRSV, and hBoV were most frequently detected. Further studies including healthy control subjects are needed to define the clinical significance of hBoV in acute wheezing. J. Med. Virol. 79: 1238–1243, 2007. © 2007 Wiley‐Liss, Inc.

Adult asthmatics display exaggerated IFNgamma responses to human metapneumovirus and respiratory syncytial virus

Human metapneumovirus and respiratory syncytial virus are RNA viruses associated with lower respiratory tract infections. Regular symptomatic re-infection and sequelae are common, particularly in individuals with pre-existing respiratory diseases, such as asthma. Our understanding of virus-dependent cytokine responses and potential differences between allergic asthmatics and non-asthmatics is limited. To test our hypothesis that adults with mild allergic asthma, the most common form of this disease, exhibit distinct pro-inflammatory responses, we developed a model using acute in vitro infection of fresh peripheral blood mononuclear cells. For both viruses, the production of innate-immunity-associated IL-6 and IL-10 was indistinguishable in the 2 populations. Type 1 cytokine production dominated adaptive immune responses in both asthmatic and non-asthmatic individuals. Surprisingly, asthmatics exhibited stronger pro-inflammatory IFNgamma production in response to human metapneumovirus than non-asthmatic adults (p = 0.01), with a similar, but statistically nonsignificant trend in the respiratory-syncytial-virus-stimulated response. Neutralizing IL-10 did not enhance the intensity of IFNgamma responses, demonstrating that this pro-inflammatory bias is not counter-regulated by IL-10. Finally, anti-TLR4 blocked lipopolysaccharide, but not respiratory-syncytial-virus-driven cytokine production. Collectively, the data demonstrate that asthma is characterized by markedly stronger pro-inflammatory IFNgamma responses to pneumoviruses than their non-asthmatic counterparts. This distinctive pattern of viral immunity may contribute to a worsening of asthma symptoms during respiratory virus infections.

Double-stranded RNA increases kinin B1 receptor expression and function in human airway epithelial cells

Increased levels of kinins have been detected within the airways during upper respiratory viral infections (URIs). Rhinovirus, the major URI associated with acute exacerbations of asthma, is an ssRNA virus that primarily infects the airway epithelium and produces dsRNA during replication. We asked whether dsRNA could increase the expression of kinin receptors in airway epithelial cells, thereby potentiating the inflammatory consequences of kinin generation. Human airway epithelial cell line BEAS-2B was stimulated with the dsRNA analog Poly I:C and kinin receptor expression detected by quantitative RT-PCR as well as radioligand binding. Poly I:C induced an increase in B1 and B2 receptor mRNA levels in BEAS-2B and primary human normal bronchial epithelial cells. At the cell surface, only B1 receptor expression was increased by Poly I:C. Furthermore, pretreatment of BEAS-2B cells with Poly I:C enhanced the induction of phospho-ERK following B1 receptor ligand stimulation. To investigate whether these finding had potential in vivo relevance, we assessed B1 receptor expression in nasal tissue obtained from 8 normal human subjects with URIs and 3 control subjects. Five of the URI subjects demonstrated increased B1 receptor mRNA compared to the 3 control subjects. We suggest that increased expression of B1 receptor in the human airway following a URI could increase the risk of an exacerbation of asthma by contributing to increased inflammation in the airway.

Understanding the September asthma epidemic

The highly predictable increase in emergency department visits, hospital admissions, and unscheduled physician consultations for childhood asthma in North America every September is uniquely related to school return. Rhinovirus infection is likely the major trigger, initially affecting asthma in school-age children, followed by similar but lesser increases in asthma morbidity in younger children and in adults. Low use of asthma medications during summer may fuel the epidemic, which may be attenuated by the short-term addition of an effective controller therapy.

Cooperative effects of rhinovirus and TNF-{alpha} on airway epithelial cell chemokine expression

Rhinovirus (RV) infections trigger exacerbations of airways disease, but underlying mechanisms remain unknown. We hypothesized that RV and cytokines present in inflamed airways combine to induce augmented airway epithelial cell chemokine expression, promoting further inflammation. To test this hypothesis in a cellular system, we examined the combined effects of RV39 and TNF-alpha, a cytokine increased in asthma and chronic obstructive pulmonary disease, on airway epithelial cell proinflammatory gene expression. Costimulation of 16HBE14o- human bronchial epithelial cells and primary mucociliary-differentiated tracheal epithelial cells with RV and TNF-alpha induced synergistic increases in IL-8 and epithelial neutrophil attractant-78 production. Similar synergism was observed for IL-8 promoter activity, demonstrating that the effect is transcriptionally mediated. Whereas increases in ICAM-1 expression and viral load were noted 16-24 h after costimulation, cooperative effects between RV39 and TNF-alpha were evident 4 h after stimulation and maintained despite incubation with blocking antibody to ICAM-1 given 2 h postinfection or UV irradiation of virus, implying that effects were not solely due to changes in ICAM-1 expression. Furthermore, RV39 infection induced phosphorylation of ERK and transactivation of the IL-8 promoter AP-1 site, which functions as a basal level enhancer, leading to enhanced TNF-alpha responses. We conclude that RV infection and TNF-alpha stimulation induce cooperative increases in epithelial cell chemokine expression, providing a cellular mechanism for RV-induced exacerbations of airways disease.

IFN-gamma-induced protein 10 is a novel biomarker of rhinovirus-induced asthma exacerbations

Background

Rhinovirus-induced acute asthma is the most frequent trigger for asthma exacerbations.

Objective

We assessed which inflammatory mediators were released from bronchial epithelial cells (BECs) after infection with rhinovirus and then determined whether they were also present in subjects with acute virus-induced asthma, with the aim to identify a biomarker or biomarkers for acute virus-induced asthma.

Methods

BECs were obtained from bronchial brushings of steroid-naive asthmatic subjects and healthy nonatopic control subjects. Cells were infected with rhinovirus 16. Inflammatory mediators were measured by means of flow cytometry with a cytometric bead array. Subjects with acute asthma and virus infection were recruited; they were characterized clinically by using lung function tests and had blood taken to measure the inflammatory mediators identified as important by the BEC experiments.

Results

IFN-γ–induced protein 10 (IP-10) and RANTES were released in the greatest quantities, followed by IL-6, IL-8, and TNF-α. Dexamethasone treatment of BECs only partially suppressed IP-10 and TNF-α but was more effective at suppressing RANTES, IL-6, and IL-8. In acute clinical asthma serum IP-10 levels were increased to a greater extent in those with acute virus-induced asthma (median of 604 pg/mL compared with 167 pg/mL in those with non–virus-induced acute asthma, P < .01). Increased serum IP-10 levels were predictive of virus-induced asthma (odds ratio, 44.3 [95% CI, 3.9-100.3]). Increased serum IP-10 levels were strongly associated with more severe airflow obstruction (r = −0.8; P < .01).

Conclusions

IP-10 release is specific to acute virus-induced asthma.

Clinical implications

Measurement of serum IP-10 could be used to predict a viral trigger to acute asthma.

Is there a role for influenza vaccination in cystic fibrosis?

BACKGROUND

Influenza vaccination is generally recommended to patients with Cystic Fibrosis (CF). Previous studies have shown that influenza infections cause worsening lung functions, disease progression and increase propensity of bacterial infections in CF. However, the clinical evidence in the effectiveness of influenza vaccination in CF is lacking.

AIMS

This study retrospectively reviewed the influenza vaccination status in the patients with CF and compared the influenza infection rates between the vaccinated and non-vaccinated groups. Finally the factors associated with non-adherence with vaccination were determined.

METHODS

Nasal swabs were obtained from 63 patients with CF between the age of 6 months to 18 years routinely and during respiratory exacerbations between October 2003 to April 2004. Influenza A and Influenza B were detected using Nucleic Acid Sequence Based Amplification (NASBA). The influenza vaccination status of these patients was retrospectively reviewed.

RESULTS

41 patients (65%) were vaccinated against influenza. For the 22 patients (35%) who were not vaccinated, 7 of them were scared of needles leading to non-adherence. Influenza virus was detected on 5 occasions; 3 were Influenza A (60%) and 2 were Influenza B (40%). 1 virus in the vaccinated group and 4 in the non-vaccinated were detected during the study period (p-value=0.046).

CONCLUSIONS

Although the current available evidence to support routine influenza vaccination is limited in CF, this study has shown that such practice may yet play a role in preventing its subsequent acquisition.

Upper airway viral infections

Upper airway viral infections (URI) are a major cause of absence from school and work. Although morbidity is low in most of the subjects, the complications of URI, including otitis media, sinusitis and exacerbations of asthma and chronic obstructive pulmonary disease (COPD) have an enormous health impact. Despite the major health care consequences associated with these complications, our understanding of how URI trigger upper airway symptoms and cause exacerbations of lower airway diseases remains limited. This article reviews our current understanding of the pathogenesis of URI, and of viral exacerbations of asthma and COPD, and considers host defense parameters that may regulate susceptibility to disease exacerbations. We will also consider current and potential therapeutic approaches for the treatment of URI and their lower airway complications.

Immunomodulatory effects of macrolide antibiotics in respiratory disease: therapeutic implications for asthma and cystic fibrosis

The macrolide antibiotics are a family of related 14- or 15-membered lactone ring antibiotics. There has been recent interest in the beneficial effects of these drugs as immune modulators in respiratory conditions in children. Cystic fibrosis (CF) and asthma, both of which occur in childhood, have an underlying inflammatory component and are associated with significant morbidity. The pathogenesis of both conditions is poorly understood but several molecular mechanisms have been suggested. In CF, these mechanisms broadly involve altered chloride transport and alteration of the airway surface liquid with disordered neutrophilic inflammation. There is much evidence for a proinflammatory propensity in CF immune effector and epithelial cells and many studies indicate that macrolides modulate these inflammatory processes. Recent studies have confirmed a clinical improvement in CF following treatment with macrolides, but the exact mechanisms by which they work are unknown. Asthma is likely to represent several different phenotypes but in all of these, airway obstruction, bronchial hyperresponsiveness, and inflammation are central processes. Results from trials using macrolides have suggested an improvement in clinical outcome. The putative mechanisms of macrolide immunomodulatory action include improvement of the primary defense mechanisms, inhibition of the bacteria-epithelial cell interaction, modulation of the signaling pathway and chemokine release, and direct neutrophil effects. Putative mechanisms of phenotypic modulation have also been proposed involving interactions with nitric oxide, endothelin-1, and bronchoconstriction, endothelial growth factors and airway remodeling, and bioactive phospholipids in both CF and asthma. Further characterization of these effects and development of targeted designer drugs will further expand our therapeutic repertoire and lead to improved quality and quantity of life for patients with CF and asthma.

Respiratory picornavirus infections in Korean children with lower respiratory tract infections

Recently, human rhinoviruses (RVs) and enteroviruses have been suggested as important etiological agents in young children with lower respiratory tract infections (LRTIs). We investigated the role of respiratory picornaviruses in hospitalized children with LRTI. A total of 233 nasopharyngeal samples were collected from hospitalized children with LRTIs from July 2004 to January 2006. All specimens were tested for the presence of human respiratory syncytial virus (hRSV), influenza virus A, influenza B, parainfluenzavirus, and adenovirus using direct immunofluorescent assay, and for human metapneumovirus (HMPV) by RT-PCR. Detection of RV was performed in nasopharyngeal samples by a RT-PCR assay that incorporated a BglI restriction enzyme digestion of the picornavirus RT-PCR amplicon, and detection of enterovirus was accomplished by hemi-nested RT-PCR using specific primers. Viral agents were detected in 70.4% (164/233) of the study population. The most frequently detected viruses were RV (64/233, 27.4%), hRSV (48/233, 20.6%), and enterovirus (43/233, 18.4%). Picornaviruses were detected as the sole viral agents in 27.0% (63/233) of children, whereas mixed viral infection was detected in 12.0%. These results suggest that picronavirus infection is an important etiological cause of LRTIs in Korean children.

Interleukin-17A modulates human airway epithelial responses to human rhinovirus infection

Human rhinovirus (HRV) infections are associated with exacerbations of asthma and chronic obstructive pulmonary disease that are characterized by a selective neutrophil infiltration. IL-17A, a cytokine derived primarily from activated T cells, has been linked to neutrophilic inflammation of the airways. We hypothesized that IL-17A alters the response of HRV-infected epithelial cells to modulate airway inflammatory cell populations. IL-17A synergistically enhanced HRV-16-induced epithelial production of the neutrophil chemoattractant, IL-8, as well as human beta-defensin-2 (HBD-2), a chemoattractant for immature dendritic cells and memory T cells, but suppressed viral production of the eosinophil chemoattractant, RANTES. These effects were not due to alterations of viral uptake or replication by IL-17A. The synergy between HRV-16 and IL-17A for IL-8 protein production was both dose- and time-dependent. IL-8 induction by IL-17A or HRV-16, alone and in combination, was reduced by inhibitors of the p38 and p44/42 MAPK pathways. By contrast, induction of HBD-2 depended on the activation of the p38 and JNK pathways. The ability of IL-17A to synergistically enhance HRV-induced IL-8 is mediated posttranscriptionally, since IL-8 promoter activation by the combination of the two stimuli was merely additive, whereas the combination of IL-17A and HRV-16 led to stabilization of IL-8 mRNA. Similarly, stimulation of HBD-2 promoter constructs by the combination of IL-17A and HRV-16 was no more than the sum of the individual responses. Further studies are needed to examine HBD-2 mRNA stability. Taken together, these data represent the first demonstration that IL-17A can modify epithelial responses to HRV in a manner that would be expected to favor the recruitment of neutrophils, immature dendritic cells, and memory T cells to the airways.

Dishing the dirt on asthma: What we can learn from poor hygiene

Allergic asthma continues to represent a huge health burden worldwide and is largely treated by non-selective immunosuppressive drugs, which often prove ineffective. The hygiene hypothesis proposes that the increased incidence of allergy and asthma in Western countries observed in the last 50 years is due to environmental changes that include improved hygiene and a lack of infections. The immunological mechanisms that must underpin such an environmental impact on immune regulation remain to be defined, making it difficult to identify specific ways of preventing development of allergy and asthma in early life. In this article we will seek to review some of the pathways that might underlie the hygiene hypothesis in an attempt to provide targets for future asthma prevention.

Nonspecific provocation of target organs in allergic diseases: EAACI-GA(2)LEN consensus report

It is widely accepted that nonspecific tissue reactivity is a distinct pathophysiological hallmark of allergic diseases, influenced by genetic and environmental factors different from those involved in causing sensitization and allergen response of target organs. This consensus document aims at reviewing procedures currently used for nonspecific provocation of the bronchi, nose and eye and for measuring their responsiveness to nonspecific stimuli.

Synergistic effects of fluticasone propionate and salmeterol on inhibiting rhinovirus-induced epithelial production of remodelling-associated growth factors

BACKGROUND

Rhinoviruses (RV), the major trigger of acute asthma exacerbations, are able to infect bronchial epithelium and induce production of pro-inflammatory, but also angiogenic and pro-fibrotic mediators. Fluticasone propionate (FP) and salmeterol (S) are clinically effective and act synergistically in controlling persistent asthma; however, their effect on virus-associated asthma is less clear.

AIM

The aim of this study was to assess the individual and combined effects of FP and S on RV-induced epithelial production of vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2).

METHODS

Bronchial epithelial cells (BEAS-2B) were exposed in vitro to RV and were subsequently treated with FP and S, at physiologically relevant concentrations, alone or in combination. VEGF and FGF-2 were measured in the supernatants of these cultures using ELISA.

RESULTS

FP was able to reduce RV-induced VEGF production in a dose-dependent manner. S also induced a smaller reduction; addition of both factors inhibited VEGF synergistically. FGF-2 production was not inhibited by either FP or S alone, but was significantly reduced when both substances were present in the culture.

CONCLUSION

This study demonstrates that FP and S may synergistically inhibit the production of angiogenic and/or pro-fibrotic factors that are induced after RV infection of BEAS-2B and are implicated in airway remodelling, suggesting that this combination may represent an important therapeutic option on virus-induced asthma.

Mechanisms of virus-induced asthma exacerbations: state-of-the-art. A GA2LEN and InterAirways document

Viral infections of the respiratory tract are the most common precipitants of acute asthma exacerbations. Exacerbations are only poorly responsive to current asthma therapies and new approaches to therapy are needed. Viruses, most frequently human rhinoviruses (RV), infect the airway epithelium, generate local and systemic immune responses, as well as neural responses, inducing inflammation and airway hyperresponsiveness. Using in vitro and in vivo experimental models the role of various proinflammatory or anti‐inflammatory mediators, antiviral responses and molecular pathways that lead from infection to symptoms has been partly unravelled. In particular, mechanisms of susceptibility to viral infection have been identified and the bronchial epithelium appeared to be a key player. Nevertheless, additional understanding of the integration between the diverse elements of the antiviral response, especially in the context of allergic airway inflammation, as well as the interactions between viral infections and other stimuli that affect airway inflammation and responsiveness may lead to novel strategies in treating and/or preventing asthma exacerbations. This review presents the current knowledge and highlights areas in need of further research.

Anti-inflammatory pharmacotherapy for wheezing in preschool children

Accumulating evidence indicates that there are at least two phenotypes of wheezing in preschool years with distinct natural history. Frequent wheezing in the first 3 years of life with risk factors for asthma (e.g., eczema, maternal asthma) predicts symptoms in older age, while infrequent viral-associated wheezing without risk factors for asthma has a benign prognosis. This systematic review summarizes evidence on the use of anti-inflammatory medications in preschool children with wheezing. Literature search was performed using Medline and the Cochrane Library. Retrieved articles were critically appraised. Episodic use of high-dose inhaled corticosteroids (>1,600 mcg/day of beclomethasone) may ameliorate severity of intermittent viral-associated wheezing. Maintenance inhaled corticosteroids can control symptoms in children with frequent wheezing associated with risk factors for asthma. Inhaled corticosteroids do not alter the natural history of wheezing even when started early in life and could have a negative impact on linear growth rate. Short courses of oral corticosteroids have been proposed as an effective measure to control exacerbations of symptoms although there is little evidence supporting their use. Some studies support the administration of non-steroidal anti-inflammatory medications (leukotriene pathway modifiers, cromones, methylxanthines) for mild frequent wheezing. Maintenance inhaled corticosteroids is the most effective measure for controlling frequent wheezing in preschool children, especially when accompanied by risk factors for asthma. This treatment does not affect the natural history of wheezing, although deceleration of linear growth rate is the most commonly recognized systemic adverse effect.

Allergies, infections and the hygiene hypothesis--the epidemiological evidence

The 'hygiene hypothesis' was first proposed by Strachan in 1989 suggesting that infections and unhygienic contact with older siblings or through other exposures may confer protection from the development of allergic illnesses. This hypothesis has evolved in various ways exploring the role of overt viral and bacterial infections, the significance of environmental exposure to microbial compounds, and their effect on underlying responses of innate and adaptive immunity. So far a truly unifying concept is still lacking, but various pieces of a complex interplay between a host's immune response, characteristics of the invading microorganism, the level and variety of the environmental exposure, and the interactions between a genetic background and a range of exposures become apparent. All these pieces eventually assemble to the clinical presentation of a complex syndrome namely of asthma and allergic illnesses. Even if today practical implications cannot directly be deduced from these findings, there is great potential for the development of novel preventive and therapeutic strategies in the future based on the concepts of the 'hygiene hypothesis'.

Risk factors for accident and emergency (A&E) attendance for asthma in inner city children

BACKGROUND

Inner city children make heavy use of accident and emergency (A&E) services for asthma. Developing strategies to reduce this requires a better understanding of the risk factors.

METHODS

A case-control study was carried out of children with asthma living in south-east London: 1018 children who attended A&E for asthma over 1 year and 394 children who had not attended A&E for asthma over the previous year. The main risk factors were socioeconomic status, home environment, routine asthma management and parents' psychological responses to and beliefs about the treatment of asthma attacks.

RESULTS

A&E attendance was more common in children living in poorer households. No associations were found with home environment or with measures of routine asthma care. Children who had attended outpatients were much more likely to attend A&E (odds ratio (OR) 13.17, 95% CI 7.13 to 24.33). Other risk factors included having a parent who reported feeling alone (OR 2.58, 95% CI 1.71 to 3.87) or panic or fear (OR 2.62. 95% CI 1.75 to 3.93) when the child's asthma was worse; and parental belief that the child would be seen more quickly in A&E than at the GP surgery (OR 2.48, 95% CI 1.62 to 3.79). Parental confidence in the GP's ability to treat asthma attacks reduced the risk of attending A&E (OR 0.30, 95% CI 0.17 to 0.54).

CONCLUSIONS

There is no evidence that passive smoking, damp homes or poor routine asthma care explains heavy inner city use of A&E in children with asthma. Reducing A&E use is unlikely to be achieved by improving these, but identifying appropriate settings for treating children with asthma attacks and communicating these effectively may do so.

What is the role of virus vaccination in patients with asthma?

It is estimated that viruses play a role in 30% to 80% of asthma exacerbations. Thus, virus vaccination in patients with asthma could play an important role in preventing asthma exacerbations and other complications. Influenza is the only agent for which a routine vaccine is currently available. This article discusses whether influenza vaccination in patients with asthma, based on the available evidence, is justified. Cost-effectiveness of (influenza) vaccination for patients with asthma is questionable. For the other major viruses involved, the present state of affairs is described. Although progress is being made, a vaccine may be available in the near future only for respiratory syncytial virus (RSV). Meanwhile, clinicians and patients should aim for an optimal treatment with the currently available asthma medication.

Mycoplasma pneumoniae and its role in asthma

Mycoplasma pneumoniae (M pneumoniae), primarily recognised as a causative agent of community-acquired pneumonia has recently been linked to asthma. An infection with M pneumoniae may precede the onset of asthma or exacerbate asthma symptoms. Chronic infection with M pneumoniae has been suspected to play a part in some patients with asthma. The role of immunoglobulin E-related hypersensitivity and induction of T helper type 2 immune response leading to inflammatory response in M pneumoniae-infected patients with asthma have also been proposed. Use of macrolides in reducing asthma symptoms only in M pneumoniae-infected patients supports the use of macrolides in patients with asthma having M pneumoniae infection. As macrolides are both antimicrobial and anti-inflammatory drugs, the therapeutic role of their biphasic nature in reducing asthma symptoms needs further attention in clinical research.

Corticosteroids and beta2 agonists differentially regulate rhinovirus-induced interleukin-6 via distinct Cis-acting elements

Interleukin-6 (IL-6) is a proinflammatory cytokine up-regulated by rhinovirus infection during acute exacerbations of asthma and chronic obstructive pulmonary disease. The role of IL-6 during exacerbations is unclear; however, it is believed IL-6 could contribute to airway and systemic inflammation. In this study we investigate the effects of common asthma treatments fluticasone propionate and beta(2) agonists salmeterol and salbutamol on IL-6 production in BEAS-2B and primary bronchial epithelial cells. Salmeterol and salbutamol enhanced rhinovirus- and IL-1beta-induced IL-6 production; however, fluticasone treatment caused a reduction of IL-6 protein and mRNA. Combined activity of salmeterol and fluticasone at equimolar concentrations had no effect on rhinovirus or IL-1beta induction of IL-6. The induction of IL-6 by salmeterol was dependent upon the beta(2) receptor and could also be induced by cAMP or cAMP-elevating agents forskolin and rolipram. Using transfection of IL-6 promoter reporter constructs, dominant negative mutants, and electromobility shift assays, it was found that NF-kappaB was the only transcription factor required for rhinovirus induction of IL-6 gene expression. Salmeterol caused an augmentation of rhinovirus-induced promoter activation via a mechanism dependent upon the c/EBP and/or CRE (cyclic AMP response element) cis-acting sites. The suppressive effect of FP was dependent upon distinct glucocorticoid response element sequences proximal to the transcriptional start site within the IL-6 promoter. The data demonstrate that beta(2) agonists can augment IL-6 expression by other stimuli in an additive manner via cyclic AMP and that the negative effect of steroids is mediated by glucocorticoid response elements within the IL-6 promoter.

Respiratory viruses in childhood asthma

PURPOSE OF REVIEW

Several epidemiological studies have confirmed the association between viral respiratory infections and wheezing episodes or exacerbations of asthma in childhood. In contrast, whether particular viral infections can be protective or able to initiate asthma is still debated; recent studies reported herein have added to our understanding in several different domains, including natural history, virology and mechanisms.

RECENT FINDINGS

Animal studies support the possibility that severe infections with respiratory syncytial virus early in life may be able to diverge the immune response towards an allergic phenotype; however, in human studies, predisposition seems dominating. Human rhinoviruses are increasingly being shown to be equally important as respiratory syncytial virus even in infancy. Newly discovered respiratory viruses have also been associated with asthma exacerbations. The interferon pathway is currently scrutinized with respect to virus-induced inflammation; furthermore, indications that viral infections may be associated with remodeling phenotypes have been recently published.

SUMMARY

Notwithstanding the progress in epidemiology and pathogenesis of virus-induced asthma, more effort is needed in assessing possible strategies for treatment. Current treatments seem to be relatively ineffective, but new pathways give a hopeful message for future therapies.

Early-life respiratory viral infections, atopic sensitization, and risk of subsequent development of persistent asthma

Background

Severe lower respiratory infections (LRIs) and atopic sensitization have been identified as independent risk factors for asthma.

Objective

The nature of potential interactions between these risk factors was the subject of this study.

Methods

A community-based cohort of 198 children at high atopic risk was followed from birth to 5 years. All episodes of acute respiratory illness in the first year were recorded and postnasal aspirates were collected for viral identification. History of wheeze and asthma was collected annually, and atopy was assessed at 6 months, 2 years, and 5 years.

Results

A total of 815 episodes of acute respiratory illness were reported, and 33% were LRIs. Viruses were detected in 69% of aspirates, most commonly rhinoviruses (48.3%) and respiratory syncytial virus (10.9%). At 5 years, 28.3%(n = 56) had current wheeze, and this was associated with wheezy [odds ratio (OR), 3.4 (1.2-9.7); P = .02] and/or febrile LRI [OR, 3.9 (1.4-10.5); P = .007], in particular those caused by respiratory syncytial virus or rhinoviruses [OR, 4.1 (1.3-12.6); P = .02]. Comparable findings were made for current asthma. Strikingly these associations were restricted to children who displayed early sensitization (≤2 years old) and not observed in nonatopic patients or those sensitized later.

Conclusion

These data suggest viral infections interact with atopy in infancy to promote later asthma. Notably the occurrence of both of these events during this narrow developmental window is associated with maximal risk for subsequent asthma, which suggests a contribution from both classes of inflammatory insults to disease pathogenesis.

Clinical implications

Protection of “high-risk” children against the effects of severe respiratory infections during infancy may represent an effective strategy for primary asthma prevention. The potential benefits of these strategies merit more careful evaluation in this age group.

The role of antibiotics in asthma

There is increasing evidence that atypical respiratory pathogens such as Chlamydophila pneumoniae and Mycoplasma pneumoniae may contribute to the pathogenesis of both stable asthma and asthma exacerbations. It is postulated that these organisms may contribute to inflammation in the airways possibly by activating inflammatory mechanisms in the respiratory tract.

The macrolide class of antibiotics may have a part to play in the management of asthma by exerting anti-inflammatory effects on the chronically inflamed airways in addition to their anti-infective action. The ketolide antibiotics may also have similar properties.

This paper discusses the role of these antibiotics in the management of asthma.

Bacterial colonization in respiratory secretions from acute and recurrent wheezing infants and children

Lower respiratory tract infection in childhood often results in airway obstruction, characterized by wheezing. However, contribution of bacterial colonization to the wheezy state in children remains unclear. Wheezing and non-wheezing children requiring hospitalization were classified into three groups: (i) wheezing children having a past history of recurrent wheezing; (ii) wheezing children without such history; and (iii) non-wheezing children as control subjects. Respiratory secretions as sputum were analyzed microscopically, and cultured. Cultured pathogenic bacterial species in sputum were categorized into two subgroups according to their amounts, i.e., dominant and non-dominant amounts of colonies. Incidence of bacterial colonization and wheezing were assessed. Hospitalized children were mainly 1- to 2-yr old, and rapidly decreased in number for older ages. Children in the three groups belonged to different clinical entities. Children in the recurrent wheezing group were highly sensitized to mite allergens, and still required hospitalization after 2 yr of age. Incidence of bacterial colonization was similar between the three groups. Dominant and non-dominant amounts of bacterial colonization were 170/997 (17.1%) and 170/997 (17.1%), respectively, in the recurrent wheezing group; 28/146 (19.2%) and 35/146 (24.0%), respectively, in the acute wheezing group; and 15/56 (26.8%) and 7/56 (12.5%), respectively, in the non-wheezing group. Regardless of the presence of wheezing, bacterial colonization commonly occurred at a young age in the three groups. In recurrent wheezing children, boys (122/611, 20.0%) carried non-dominant amounts of bacteria more frequently than girls (48/386, 12.4%) (p < 0.01). Boys showed predominant wheezing and susceptibility to bacterial colonization. Assessment of bacterial colonization allowed us to characterize asthma onset and outgrowth in childhood.

Laser acupuncture and probiotics in school age children with asthma: a randomized, placebo-controlled pilot study of therapy guided by principles of Traditional Chinese Medicine

Traditional Chinese Medicine (TCM) postulates an interaction between the lung as a Yin-organ and the large intestine as a Yang-organ. The aim of this pilot study was to investigate in asthmatic school age children whether treatment with laser acupuncture and probiotics according to TCM portends a clinical benefit to standard medical treatment performed according to pediatric guidelines. Seventeen children aged 6-12 yr with intermittent or mild persistent asthma were enrolled in this randomized, placebo-controlled, double-blind pilot study. Eight patients received laser acupuncture for 10 wk and probiotic treatment in the form of oral drops (living non-pathogenic Enterococcus faecalis) for 7 wk. Nine patients in the control group were treated with a laser pen which did not emit laser light and were given placebo drops. Peak flow variability (PFV) and forced expiratory volume in 1 s (FEV(1)) were measured and Quality of Life was assessed by a standardized questionnaire. Laser acupuncture and probiotics significantly decreased mean (standard deviation) weekly PFV as a measurement of bronchial hyperreactivity by -17.4% (14.2) in the TCM group vs. 2.2% (22.5) in the control group (p = 0.034). No significant effect was detected for FEV(1), Quality of Life criteria and additional medication. As an exploratory result, patients in the TCM group had fewer days of acute febrile infections when compared with the control group [1.14 (1.4) vs. 2.66 (2.5), p = 0.18]. In conclusion, this pilot study generates the hypothesis that the interactive treatment of lung and large intestine according to TCM by laser acupuncture and probiotics has a beneficial clinical effect on bronchial hyperreactivity in school age children with intermittent or mild persistent asthma and might be helpful in the prevention of acute respiratory exacerbations. These results should be confirmed by further studies.

[Role of rhinovirus in respiratory tract infections in hospitalized children]

BACKGROUND

Rhinovirus is a recognized cause of common cold and has been shown to cause asthma exacerbations in adults and children. The burden of rhinovirus infections in hospitalized children has not been described in Spain.

OBJECTIVE

To describe confirmed rhinovirus infections in children hospitalized for respiratory tract infection in a secondary public hospital.

PATIENTS AND METHODS

We performed a prospective descriptive study in children admitted to hospital with fever or respiratory tract infection and with a positive isolation of rhinovirus in nasopharyngeal washings between September 2004 and July 2005. Virological diagnosis was made with direct immunofluorescent assay and/or reverse transcription-polymerase chain reaction in specimens obtained from nasopharyngeal washings. The clinical characteristics of the patients were analyzed.

RESULTS

There were 76 children with rhinovirus infection, representing 25 % of admissions in 304 children with fever or respiratory tract infection. Rhinovirus was the second most frequent viral agent identified after respiratory syncytial virus (RSV) (29.9 % of admissions). Fifty-four children (71.1 %) were under 2 years of age. The most frequent clinical diagnoses were recurrent wheezing in 60.5 %, bronchiolitis in 23.7 %, pneumonia in 7.9 %, and upper respiratory tract infection in 5.3 %. Fever > 38 degrees C was present in 57.9 % of the patients and radiologic infiltrate was found in 23.7 %. Oxygen saturation less than 95 % was found in 43.4 % of the patients. Of 22 children aged more than 2 years, a diagnosis of asthmatic crisis was made in 21.

CONCLUSIONS

Rhinoviruses were frequently identified in hospitalized children with respiratory tract disease and were the second most common viruses after RSV. In our series, it was the most frequent cause of recurrent wheezing in hospitalized children and the second most common cause in infants.

Hochu-ekki-to inhibits rhinovirus infection in human tracheal epithelial cells

BACKGROUND AND PURPOSE

A traditional Japanese herbal medicine, hochu-ekki-to, has been used for the symptomatic treatment of the common cold and to reduce the frequency of colds in patients with chronic obstructive pulmonary disease. However, the inhibitory effects of hochu-ekki-to on infection by rhinovirus (RV), the major cause of common colds, have not been studied.

EXPERIMENTAL APPROACH

Human tracheal epithelial cells in culture were infected with a major group rhinovirus-RV14. Virus output and viral RNA were measured along with interleukin (IL)-1beta, IL-6, IL-8 and tumor necrosis factor (TNF)-alpha), mRNA for intercellular adhesion molecule (ICAM)-1 and acidic endosomes in cells.

KEY RESULTS

RV14 infection increased virus titers, the content of cytokines in supernatants and RV14 RNA in the cells. Hochu-ekki-to decreased virus output, RV14 RNA in the cells, susceptibility to RV infection and supernatant cytokine concentrations after RV14 infection. Hochu-ekki-to reduced mRNA for ICAM-1, the receptor for RV14, the concentration of the soluble form of ICAM-1 and the number and fluorescence intensity of acidic endosomes in the cells, from which RV RNA enters into the cytoplasm, at RV14 infection. Glycyrrhizin, one of the chemical constituents of hochu-ekki-to, reduced supernatant virus titers dose-dependently.

CONCLUSION AND IMPLICATIONS

Hochu-ekki-to inhibited RV14 infection by decreasing ICAM-1 and by blocking entry of viral RNA into the cytoplasm from the endosomes, in airway epithelial cells. Glycyrrhizin may be partly responsible for inhibition of RV infection by hochu-ekki-to. Hochu-ekki-to could modulate airway inflammation by reducing production of cytokines in RV infections.

Human bocavirus: a novel parvovirus epidemiologically associated with pneumonia requiring hospitalization in Thailand

Background. We detected human bocavirus (HBoV) infection in 4.5% of hospitalized patients with pneumonia in rural Thailand. However, the role of HBoV as a pathogen is unclear.

Methods. We compared HBoV infection in patients with pneumonia with that in asymptomatic control patients enrolled between 1 September 2004 and 31 August 2005 in the same hospitals in Thailand.We examined outpatients with influenza-like illness for HBoV infection and tested for 13 additional respiratory viruses. Epidemiologic and clinical characteristics of HBoV infection are described.

Results. HBoV infection was detected in 20 (3.9%) of 512 outpatients and 3 (1%) of 280 control patients. Coinfection with other viruses was detected in 83% of patients with pneumonia and in 90% of outpatients. Compared with control patients, HBoV infection was significantly associated with pneumonia requiring hospitalization (adjusted odds ratio, 3.56 [95% confidence interval, 1.06–11.91]; P = .04). Eighty-three percent of HBoV infections were detected in patients with pneumonia who were <5 years old. More patients with pneumonia associated with HBoV—respiratory syncytial virus (RSV) or human parainfluenza virus (HPIV) coinfections had wheezing than patients with RSV and HPIV infections alone (9 [53%] of 17 vs. 32 [23%] of 138]; P = .01).

Conclusions. HBoV infection was epidemiologically associated with pneumonia among young children in rural Thailand, but infection and illness may be dependent on coinfection with other viruses.

Rhinovirus-associated hospitalizations in young children

Background. Rhinoviruses frequently cause the common cold but have not been considered important causes of acute respiratory hospitalizations in children.

Methods. A population-based surveillance study was performed among children <5 years of age who were hospitalized with respiratory symptoms or fever and who resided within counties encompassing Nashville, Tennessee, or Rochester, New York, from October 2000 through September 2001. Data collected included questionnaires, nasal and throat swabs for viral culture and polymerase chain reaction testing, and chart review. Rates of rhinovirus-associated hospitalizations were calculated.

Results. Of 592 children enrolled, 156 (26%) were rhinovirus positive, representing 4.8 (95% confidence interval [CI], 4.3–5.2) rhinovirus-associated hospitalizations/1000 children. Age-specific rates per 1000 children were 17.6 (95% CI, 14.9–20.6) for 0–5-month-olds, 6.0 (95% CI, 5.0–7.0) for 6–23-month-olds, and 2.0 (95% CI, 1.6, 2.4) for 24–59-month-olds (P<.01) Children with a history of wheezing/asthma had significantly more rhinovirusassociated hospitalizations than those without a history (25.3/1000 children [95% CI, 21.6–29.5/1000 children] vs. 3.1/1000 children [95% CI, 2.7–3.5/1000 children]).

Conclusions. Rhinoviruses were associated with nearly 5 hospitalizations/1000 children <5 years of age and were highest in children with a history of wheezing/asthma.

Recurrent respiratory infections and phagocytosis in childhood

BACKGROUND

About 10% of pre-school children has recurrent respiratory infections (RRI), which could be related to environmental and/or immunological factors. The aim of the present study has been to evaluate the impact of phagocytosis (FAG) and reactive oxygen intermediates (ROI) production deficiencies on pediatric RRI by the measurement of FAG and ROI activity of the polymorphonuclear neutrophils.

METHODS

Serum immunoglobulins, IgG subclasses, lymphocytic subpopulations, FAG and ROI tests were measured in 90 children with RRI, in a moment of well-being and off all medications for at least 4 weeks. FAG and ROI tests were also measured in 19 healthy children.

RESULTS

FAG (91.4 +/- 11.5%) and ROI (81.8 +/- 17.5%) of patients resulted in significantly decreased measurements compared to the control values (95.2 +/- 1.8% and 89.7 +/- 4.8%, respectively). No significant difference was manifest between the mean values of FAG and ROI tests among the patients when they were divided for age (above and below 6 years). A significant decreased likelihood of abnormal ROI (odds ratio, 0.3; 95% confidence interval, 0.07-0.97) was found in the patients with low IgA.

CONCLUSIONS

The authors' results permit only to suppose an etiological role of FAG and ROI deficiencies of polymorphonuclear neutrophils in the genesis of pediatric RRI, irrespective of the age of the patients, and further studies are necessary for confirmation.

Asthma control or severity: that is the question

In the first National Heart Lung and Blood Institute and Global Initiative for Asthma (GINA) guidelines, the level of symptoms and airflow limitation and its variability allowed asthma to be subdivided by severity into four subcategories (intermittent, mild persistent, moderate persistent, and severe persistent). It is important to recognize, however, that asthma severity involves both the severity of the underlying disease and its responsiveness to treatment. Thus, the first update of the GINA guidelines defined asthma severity depending on the clinical features already proposed as well as the current treatment of the patient. In addition, severity is not a fixed feature of asthma, but may change over months or years, whereas the classification by severity suggests a static feature. Moreover, using severity as an outcome measure has limited value in predicting what treatment will be required and what the response to that treatment might be. Because of these considerations, the classification of asthma severity is no longer recommended as the basis for treatment decisions, a periodic assessment of asthma control being more relevant and useful.

Neuraminidase inhibitors for preventing and treating influenza in children

BACKGROUND

During epidemic years, influenza attack rates in children exceed 40%. Options for prevention and treatment include the neuraminidase inhibitors: zanamivir and oseltamivir.

OBJECTIVES

To assess the efficacy, safety and tolerability of neuraminidase inhibitors in the treatment and prevention of influenza infection in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005); MEDLINE (1966 to April 2005); EMBASE (January 1980 to December 2004); the on-line GlaxoSmithKline Clinical Trials Register; the on-line Roche Clinical Trial Protocol Registry and Clinical Trial Results Database (August 2005); and reference lists of articles. We also scrutinised web sites of European and US regulatory bodies and contacted manufacturers and authors.

SELECTION CRITERIA

Double-blind, randomised, controlled trials comparing neuraminidase inhibitors with placebo or other antiviral drugs in children less than 12 years of age. Additional safety and tolerability data from other sources were also included.

DATA COLLECTION AND ANALYSIS

Four authors applied the inclusion criteria to the retrieved studies, assessed trial quality and extracted data. Data were analysed separately for oseltamivir and zanamivir.

MAIN RESULTS

Three trials involving 1500 children with a clinical case definition of influenza were included, of whom 977 had laboratory-confirmed influenza. Overall, trial quality was good. Oseltamivir reduced the median duration of illness by 26% (36 hours) in healthy children with laboratory-confirmed influenza (P value less than 0.0001). The reduction was only 7.7% (10 hours) in 'at risk' (asthmatic) children, and this did not reach statistical significance (P value = 0.54). Zanamivir reduced the median duration of illness by 24% (1.25 days) in healthy children with laboratory-confirmed influenza (P value less than 0.001). No data in 'at risk' children were available. Only oseltamivir produced a significant reduction in the complications of influenza (particularly otitis media), although there was a trend to benefit for zanamivir. We identified one randomised, controlled trial of oseltamivir for the prevention of influenza transmission in households, reporting data from 222 paediatric contacts. Where index cases had laboratory-confirmed influenza, a protective efficacy of 55% was observed, but this did not reach statistical significance (P value = 0.089). The adverse events profile of zanamivir was no worse than placebo, but vomiting was more common in children treated with oseltamivir.

AUTHORS' CONCLUSIONS

Neuraminidase inhibitors are effective in shortening illness duration in healthy children with influenza, but efficacy in 'at risk' children remains to be proven. Oseltamivir is also effective in reducing the incidence of secondary complications, and may be effective for influenza prophylaxis.

Epidemiological and clinical features of hMPV, RSV and RVs infections in young children

BACKGROUND

Human metapneumovirus (hMPV) has recently been isolated from children with acute respiratory tract infections (RTIs). The epidemiological and clinical characteristics of hMPV infection need further investigation.

OBJECTIVES

The purpose of this study was to compare the clinical features of hMPV, respiratory syncytial virus (RSV) and rhinoviruses (RV) infections in children less than 3 years of age presenting to an emergency department with acute respiratory illness.

STUDY DESIGN

From December 2002 to April 2004, all children under age three (n=931) admitted for acute respiratory illness to Dijon Hospital, France, were investigated for respiratory viruses in nasal washes.

RESULTS

hMPV was detected in 6% of children (in 10.1% (n=38) the first winter and in 3.3% (n=17) the second winter); RSV was detected in 28.5% of the children, while rhinoviruses were found in 18.3%. Five hMPV-infected children had evidence of dual infection, two with RSV and three others with RV. The median age of the patients with hMPV infection was 6 months, and the main clinical symptoms were rhinorrhea (74.5%) and cough (67%). A lower tract disease occurred in 66% of hMPV-positive patients. Gene sequencing of hMPV isolates revealed co-circulation of the two major groups of hMPV during the study period; no difference in pathogenicity was found. There was no difference in the prevalence of bronchiolitis where hMPV, RSV or rhinoviruses were present. Asthma was found more often in hospitalized children with hMPV and rhinoviruses than among those with RSV (p<0.001).

CONCLUSIONS

These results provide further evidence of the importance of hMPV as a pathogen associated with respiratory tract infection in children.

Review of guidelines and the literature in the treatment of acute bronchospasm in asthma

Asthma is a common chronic condition that disproportionately affects persons younger than 45 years. Asthma exacerbations can be sudden and severe, requiring treatment in the emergency department or hospitalization. Children younger than 15 years are 2-4 times more likely to have asthma as the first-listed hospital discharge diagnosis compared with those in other age groups. An estimated 12.8 million missed school days and 24.5 million lost work days due to asthma occurred in 2003. Drugs used in the treatment of acute asthma include inhaled beta(2)-agonists, oral corticosteroids, and inhaled anticholinergics. Levalbuterol was evaluated in several recent trials for treatment of asthma in the emergency department, for its effect in improving pulmonary function and on hospitalization rate. Theophylline, intravenous beta(2)-agonists, intravenous magnesium sulfate, and inhaled anesthetics have not been proven useful in the emergency management of asthma. The effectiveness of inhalation devices is dependent on age, cooperation of the patient, and technique.

Syk is downstream of intercellular adhesion molecule-1 and mediates human rhinovirus activation of p38 MAPK in airway epithelial cells

The airway epithelium is the primary target of inhaled pathogens such as human rhinovirus (HRV). Airway epithelial cells express ICAM-1, the major receptor for HRV. HRV binding to ICAM-1 mediates not only viral entry and replication but also a signaling cascade that leads to enhanced inflammatory mediator production. The specific signaling molecules and pathways activated by HRV-ICAM-1 interactions are not well characterized, although studies in human airway epithelia implicate a role for the p38 MAPK in HRV-induced cytokine production. In the current study, we report that Syk, an important immunoregulatory protein tyrosine kinase, is highly expressed by primary and cultured human airway epithelial cells and is activated in response to infection with HRV16. Biochemical studies revealed that ICAM-1 engagement by HRV and cross-linking Abs enhanced the coassociation of Syk with ICAM-1 and ezrin, a cytoskeletal linker protein. In polarized airway epithelial cells, Syk is diffusely distributed in the cytosol under basal conditions but, following engagement of ICAM-1 by cross-linking Abs, is recruited to the plasma membrane. The enhanced Syk-ICAM-1 association following HRV exposure is accompanied by Syk phosphorylation. ICAM-1 engagement by HRV and cross-linking Abs also induced phosphorylation of p38 in a Syk-dependent manner, and conversely, knockdown of Syk by short interfering (si)RNA substantially diminished p38 activation and IL-8 gene expression. Taken together, these observations identify Syk as an important mediator of the airway epithelial cell inflammatory response by modulating p38 phosphorylation and IL-8 gene expression following ICAM-1 engagement by HRV.

Transforming growth factor beta enhances respiratory syncytial virus replication and tumor necrosis factor alpha induction in human epithelial cells

Asthma is characterized as a chronic inflammatory disease associated with significant tissue remodeling. Patients with asthma are more susceptible to virus-induced exacerbation, which subsequently can lead to increased rates of hospitalization and mortality. While the most common cause of asthma-related deaths is respiratory viral infections, the underlying factors in the lung environment which render asthmatic subjects more susceptible to viral exacerbation are not yet identified. Since transforming growth factor beta (TGF-beta) is a critical cytokine for lung tissue remodeling and asthma phenotype, we have focused on the effects of TGF-beta on viral replication and virus-induced inflammation. Treatment of human epithelial cells with TGF-beta increased respiratory syncytial virus (RSV) replication by approximately fourfold. Tumor necrosis factor alpha (TNF-alpha) mRNA and protein expression were also significantly increased above levels with RSV infection alone. The increase in RSV replication and TNF-alpha expression after TGF-beta treatment was concomitant with an increase in virus-induced p38 mitogen-activated protein kinase activation. Our data reveal a novel effect for TGF-beta on RSV replication and provide a potential mechanism for the exaggerated inflammatory response observed in asthmatic subjects during respiratory viral infections.