The relationship between atopic status and IL-10 nasal lavage levels in the acute and persistent inflammatory response to upper respiratory tract infection

Viruses in chronic rhinosinusitis: a systematic review

Background

Unlike acute rhinosinusitis (ARS) which is mostly viral in etiology, the role of viruses in chronic rhinosinusitis (CRS) remains unclear. Viruses may play a role in initiation, exacerbations or perpetuate chronic inflammatory responses in the sinonasal mucosa. Research needs to characterize whether viruses are part of the normal sinonasal microbiome, colonizers or pathogenic.

Methods

Systematic review of the English literature was conducted. Following databases were searched with an initial search conducted in November 2021 and then updated through June 2023: Ovid Medline (1946 to present), Ovid Embase (1988 to present), Scopus (2004 to present) and Web of Science (1975 to present). MeSH (Medical Subject Headings) terms included: viruses, virus diseases, sinusitis, and rhinovirus. Keywords: virus, viral infection*, sinusitis, rhinovirus, chronic rhinosinusitis, CRS, respiratory virus, respiratory infection*, and exacerbat*. A supplementary search was conducted through September 2023: Ovid Medline (1946 to present), Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Ovid MEDLINE(R) Daily. Keywords used were: virus, viral infection*, sinusitis, chronic rhinosinusitis, CRS, respiratory virus, respiratory infection*, and exacerbat*.

Results

Thirty studies on viruses in CRS met inclusion criteria for full review. These included 17 studies on prevalence of virus in CRS, 5 examining probable causes of host susceptibility to viral infections in CRS, and 8 studies examining pathological pathways in viral association of CRS. The prevalence of viruses in nasal specimens of CRS subjects was higher as compared to controls in most studies, though a few studies showed otherwise. Rhinovirus was the most common virus detected. Studies showed that viruses may be associated with persistent hyper-responsiveness in the sinonasal mucosa, susceptibility to bacterial infections, upregulation of genes involved in the immune response and airway remodeling as well as CRS exacerbations. Presence of viruses was also associated with worse symptom severity scores in CRS subjects.

Conclusion

Most data show higher presence of viruses in nasal and serum samples of CRS subjects as compared to controls but their exact role in CRS pathophysiology in unclear. Large studies with longitudinal sampling at all disease phases (i.e., prior to disease initiation, during disease initiation, during disease persistence, and during exacerbations) using standardized sampling techniques are needed to definitively elucidate the role of virus in CRS.

Endotypes of chronic rhinosinusitis based on inflammatory and remodeling factors

BACKGROUND

Previous studies on the endotyping of chronic rhinosinusitis (CRS) that were based on inflammatory factors have broadened our understanding of the disease. However, the endotype of CRS combined with inflammatory and remodeling features has not yet been clearly elucidated.

OBJECTIVE

We sought to identify the endotypes of patients with CRS according to inflammatory and remodeling factors.

METHODS

Forty-eight inflammatory and remodeling factors in the nasal mucosal tissues of 128 CRS patients and 24 control subjects from northern China were analyzed by Luminex, ELISA, and ImmunoCAP. Sixteen factors were used to perform the cluster analysis. The characteristics of each cluster were analyzed using correlation analysis and validated by immunofluorescence staining.

RESULTS

Patients were classified into 5 clusters. Clusters 1 and 2 showed non-type 2 signatures with low biomarker concentrations, except for IL-19 and IL-27. Cluster 3 involved a low type 2 endotype with the highest expression of neutrophil factors, such as granulocyte colony-stimulating factor, IL-8, and myeloperoxidase, and remodeling factors, such as matrix metalloproteinases and fibronectin. Cluster 4 exhibited moderate type 2 inflammation. Cluster 5 exhibited high type 2 inflammation, which was associated with relatively higher levels of neutrophil and remodeling factors. The proportion of CRS with nasal polyps, asthma, allergies, anosmia, aspirin sensitivity, and the recurrence of CRS increased from clusters 1 to 5.

CONCLUSION

Diverse inflammatory mechanisms result in distinct CRS endotypes and remodeling profiles. The explicit differentiation and accurate description of these endotypes will guide targeted treatment decisions.

Differentiating Rhinitis in the Paediatric Population by Giving Focus on Medical History and Clinical Examination

Chronic rhinitis is defined as an inflammation of the nasal epithelium, and is characterized by the presence of two or more specific nasal symptoms including obstruction, rhinorrhea, sneezing, and/or itching for at least 12 weeks. In childhood, this clinical entity is very common and carries a significant socioeconomic burden. The impact on the physical, social, and psychological well-being of family cannot be underestimated. Rhinitis is an umbrella term which includes different phenotypes of rhinitis with distinct underlying pathophysiologic mechanisms. In most cases the diagnosis of rhinitis is rather straightforward; however, sometimes when based on clinical symptomatology, characterization may be challenging. Herein, we provide guidance for getting all the data needed for the differential diagnosis of rhinitis based on medical history and clinical examination.

Nasal Airflow, Mucociliary Clearance, and Sinus Functioning during Viral Colds: Effects of Allergic Rhinitis and Susceptibility to Recurrent Sinusitis

Background

The aim was to compare nasal airflow and mucociliary clearance (MCC) and their association with paranasal sinus functioning during acute natural colds and convalescence in allergic and sinusitis-susceptible patients and healthy controls.

Methods

Nine allergic subjects, 16 sinusitis-susceptible subjects, and 20 healthy controls were examined during days 2–4 of acute colds and 3 weeks later by taking viral specimens, recording symptoms, performing rhinomanometry and dyed saccharin tests, and evaluating sinus functioning with computed tomography (CT).

Results

Viral etiology of the cold was identified in 31 (69%) subjects. Nasal airflow was decreased and MCC time prolonged during the cold compared to convalescence. A higher proportion of the allergic subjects, but not of the sinusitis-susceptible subjects, compared to the control subjects tended to have abnormal nasal airflow and MCC values. Abnormal nasal airflow and MCC values associated significantly with higher ipsilateral paranasal sinus CT scores.

Conclusion

Abnormal nasal airflow and MCC rates seem to be associated with impaired functioning of paranasal sinuses during viral colds and tend to be more common in allergic subjects.

Role of hygienic factors in the etiology of allergic disorders in children

BACKGROUND/AIM

We investigated the role of body flora and chronic inflammatory infections in the etiology of allergic disorders in Turkish children.

MATERIALS AND METHODS

Forty pediatric asthma patients with positive skin prick tests and 40 age-matched healthy subjects with negative skin prick tests were enrolled in this cross-sectional study. Serum H. pylori IgG, viral hepatitis serology, IL-10, and TGF-beta levels were measured. Stool and throat cultures were taken and tested for occurrence of microorganisms.

RESULTS

A significantly higher percentage of nonatopic subjects tested positive for anti-H. pylori antibodies compared to atopic subjects (60% vs. 20%). Serum IL-10 levels were also significantly higher in nonatopic subjects. No significant differences in direct microscopy and culture specimens of stools were observed. Examination of throat flora showed significantly higher occurrences of Neisseria and beta-hemolytic Streptococcus in nonatopic subjects, but higher occurrences of gram-positive bacilli in atopic subjects.

CONCLUSION

Higher prevalence of anti-H. pylori antibody and higher serum levels of IL-10 in nonatopic subjects suggest that chronic infection and inflammation may protect against atopic disease. Higher occurrences of Neisseria and beta-hemolytic Streptococcus in throat cultures from nonatopic subjects are novel findings that lend further support to the hygiene hypothesis.

Longitudinal analysis of inflammatory biomarkers during acute rhinosinusitis

Objective

To illuminate the pathophysiology of acute rhinosinusitis (ARS) with sequential monitoring of inflammatory biomarkers during an ARS episode and to clarify their diagnostic usability in bacterial ARS.

Study Design

Inception cohort study with 50 conscripts with ARS.

Methods

We collected peripheral blood high‐sensitive C‐reactive protein (hs‐CRP), white blood cell (WBC), procalcitonin, and nasal nitric oxide (nNO) counts at 2 to 3 and 9 to 10 days of symptoms during an ARS episode. We simultaneously gathered various clinical parameters and microbiological samples. Bacterial ARS was confirmed with a positive culture of sinus aspirate.

Results

Reciprocal correlations and a significant change in biomarker levels between the two visits suggest that ARS involves a local and systemic inflammatory response that was strongest at 2 to 3 days. High‐sensitive CRP and nNO reflected responses best (52% had increased CRP levels at 2–3 days; 66% had decreased nNO levels). White blood cell and procalcitonin counts rarely exceeded the reference range. Increased local and systemic inflammatory response were linked to multiple, adenoviral, or influenza A viral etiology or the detection of bacterial ARS. Local response correlated with imaging findings of wide paranasal sinus involvement and ostiomeatal complex occlusion. At 9 to 10 days, elevated (≥ 11 mg/L) and moderately elevated (≥ 49 mg/L) hs‐CRP predicted bacterial ARS well (likelihood ratio [LR]+ 3.3 and LR+ 15.8, respectively), but the sensitivity for both findings remained low.

Conclusion

Acute rhinosinusitis (particularly bacterial ARS) involves a local and systemic inflammatory response that is strongest at the beginning of symptoms. Elevated hs‐CRP supports the diagnosis of bacterial ARS.

Level of Evidence

4. Laryngoscope, 2016 127:E55–E61, 2017

Paediatric rhinitis: position paper of the European Academy of Allergy and Clinical Immunology

Rhinitis is a common problem in childhood and adolescence and impacts negatively on physical, social and psychological well-being. This position paper, prepared by the European Academy of Allergy and Clinical Immunology Taskforce on Rhinitis in Children, aims to provide evidence-based recommendations for the diagnosis and therapy of paediatric rhinitis. Rhinitis is characterized by at least two nasal symptoms: rhinorrhoea, blockage, sneezing or itching. It is classified as allergic rhinitis, infectious rhinitis and nonallergic, noninfectious rhinitis. Similar symptoms may occur with other conditions such as adenoidal hypertrophy, septal deviation and nasal polyps. Examination by anterior rhinoscopy and allergy tests may help to substantiate a diagnosis of allergic rhinitis. Avoidance of relevant allergens may be helpful for allergic rhinitis (AR). Oral and intranasal antihistamines and nasal corticosteroids are both appropriate for first-line AR treatment although the latter are more effective. Once-daily forms of corticosteroids are preferred given their improved safety profile. Potentially useful add-on therapies for AR include oral leukotriene receptor antagonists, short bursts of a nasal decongestant, saline douches and nasal anticholinergics. Allergen-specific immunotherapy is helpful in IgE-mediated AR and may prevent the progression of allergic disease. There are still a number of areas that need to be clarified in the management of rhinitis in children and adolescents.

Anti-bacterial IgE in the antibody responses of house dust mite allergic children convalescent from asthma exacerbation

Background Atopic sensitization to the house dust mite (HDM) is associated with altered antibody responses to the nasopharyngeal colonizing bacterium Haemophilus influenzae and children admitted to the emergency department for asthma exacerbation have reduced IgG responses to HDM allergens.

Objective To investigate anti‐bacterial and anti‐allergen antibody responses during convalescence from asthma exacerbation and differences found in exacerbations associated with and without viral infection.

Results IgE antibodies to the P6 bacterial antigen increased in 60% of sera during convalescence and for many children achieved titres as high as IgE titres to allergens. In contrast IgE anti‐HDM titres declined during convalescence. The anti‐bacterial IgE titres were the same in subjects with and without virus infection while the anti‐HDM IgE declined more rapidly in virus‐infected subjects. IgG titres to the major HDM allergens showed no consistent increase and the overall IgG anti‐HDM titres even declined in subjects without a virus infection. Anti‐bacterial IgG antibodies in contrast to IgE did not change. Patients with frequent episodic or persistent asthma had similar IgE anti‐bacterial titres to patients with infrequent asthma during the acute phase, although they had reduced IgG titres to both the bacteria and the HDM.

Conclusions During the period following an acute exacerbation of asthma there was a marked and specific increase in anti‐bacterial IgE compared with a reduced IgE response to HDM. This provides further support for the concept of T‐helper type 2 responses to bacterial antigens playing a role in asthma pathogenesis.

Inhibition of interleukin-10 signaling in lung dendritic cells by toll-like receptor 4 ligands

The homeostatic microenvironment in lung is immunosuppressive and interleukin-10 (IL-10) helps maintain this microenvironment. Despite constitutive production of IL-10 in normal lung, macrophages (MØs) and dentritic cells (DCs) remain capable of responding to microorganisms, suggesting that these innate immune cells have a mechanism to override the immunosuppressive effects of IL-10. Prior studies by the authors revealed that Toll-like receptor (TLR) ligands inhibit IL-10 receptor signaling in alveolar macrophages (AMØs), thereby obviating the immunosuppressive activity of IL-10. This report compares the immunologic phenotypes of AMØs and lung DCs and their ability to respond to IL-10 following exposure to microbial stimuli. IL-10 was constitutively produced by normal lung epithelium and exposure to lipopolysaccharide (LPS) in vivo increased the expression of IL-10 during the first 24 hours. AMØs constitutively produced IL-10 mRNA, whereas both AMØs and LDCs constitutively expressed IL-12 mRNA. AMØs and LDCs, as well as bone marrow-derived MØs and DCs, had reduced capacity to activate STAT3 in response to IL-10 if pretreated with LPS. Inhibition was not associated with decreased expression of IL-10 receptor (IL-10R) and was dependent on the MyD88 signaling pathway. These results demonstrate a common underlying regulatory mechanism in both DCs and MØs by which microbial stimuli can override the immunosuppressive effect of constitutive IL-10 production in the lung.

Infections

This chapter reviews the epidemiological evidence implicating infectious pathogens as triggers and will discuss the mechanisms of interaction between the host–pathogen response and preexisting airway pathology that result in an exacerbation. Asthma is a multifaceted syndrome involving atopy, bronchial hyperreactivity, and IgE and non-IgE-mediated acute and chronic immune responses. The asthmatic airway is characterized by an infiltrate of eosinophils and of T-lymphocytes expressing the type 2 cytokines IL-4, IL-5, and IL-13. Trigger factors associated with acute exacerbations of asthma include exposure to environmental allergens, especially animals, molds, pollens and mites, cold, exercise, and drugs. The frequency of exacerbations is a major factor in the quality of life of patients with COPD. The typical clinical features of an exacerbation include increased dyspnea, wheezing, cough, sputum production, and worsened gas exchange. Although noninfectious causes of exacerbations such as allergy, air pollution, or inhaled irritants including cigarette smoke may be important, acute airway infections are the major precipitants. The infection and consequent host inflammatory response result in increased airway obstruction. The success of vaccination to prevent respiratory virus infections has been limited by significant variation within the major virus types causing disease. Currently much of the treatment of infective exacerbations of asthma and COPD is symptomatic, consisting of increased bronchodilators, either short-acting β 2—agonists in inhaled or intravenous form or anticholinergics or theophyllines, or supportive in the form of oxygen and in severe cases noninvasive or invasive ventilatory measures.

Effects of intranasal TNFalpha on granulocyte recruitment and activity in healthy subjects and patients with allergic rhinitis

Background

TNFα may contribute to the pathophysiology of airway inflammation. For example, we have recently shown that nasal administration of TNFα produces late phase co-appearance of granulocyte and plasma exudation markers on the mucosal surface. The objective of the present study was to examine indices of granulocyte presence and activity in response to intranasal TNFα challenge.

Methods

Healthy subjects and patients with allergic rhinitis (examined out of season) were subjected to nasal challenge with TNFα (10 μg) in a sham-controlled and crossover design. Nasal lavages were carried out prior to and 24 hours post challenge. Nasal biopsies were obtained post challenge. Nasal lavage fluid levels of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) were analyzed as indices of neutrophil and eosinophil activity. Moreover, IL-8 and α₂-macroglobulin were analyzed as markers of pro-inflammatory cytokine production and plasma exudation. Nasal biopsy numbers of neutrophils and eosinophils were monitored.

Results

Nasal lavage fluid levels of MPO recorded 24 hours post TNFα challenge were increased in healthy subjects (p = 0.0081) and in patients with allergic rhinitis (p = 0.0081) (c.f. sham challenge). Similarly, α₂-macroglobulin was increased in healthy subjects (p = 0.014) and in patients with allergic rhinitis (p = 0.0034). Lavage fluid levels of ECP and IL-8 were not affected by TNFα challenge. TNFα increased the numbers of subepithelial neutrophils (p = 0.0021), but not the numbers of eosinophils.

Conclusion

TNFα produces a nasal inflammatory response in humans that is characterised by late phase (i.e., 24 hours post challenge) neutrophil activity and plasma exudation.

Peripheral blood mononuclear cell NF-kappaB p105 mRNA decreases during asthmatic attacks

BACKGROUND

NF-kappaB is a transcription factor involved in expression of many inflammatory cytokines, chemical transmitters, and adhesion molecules. It has been reported to play a major role in the pathogenesis of asthma. NF-kappaB p50, which is the actual subunit that results from the cleavage of p105, is required for the induction of eosinophilia via IL-5 and chemokines.

METHODS

The subjects were 10 patients with a mean age of 59.3 years (14-82 years). NF-kappaB p105 mRNA in peripheral blood mononuclear cells during the presence or absence of asthmatic attacks was investigated. Total RNA was extracted from peripheral blood mononuclear cells. After cDNA was synthesized using random primers, NF-kappaB p105 mRNA level was measured by real-time polymerase chain reaction.

RESULTS

The NF-kappaB p105 mRNA level in peripheral blood mononuclear cells was lower during asthmatic attacks than in the absence of attacks, showing a significant difference (Wilcoxon's signed rank test: p<0.01).

CONCLUSIONS

A drop in NF-kappaB p105 during an asthma attack could result in increased NF-kappaB activity. There is a possibility that a change in the NF-kappaB p105 mRNA level might indicate some pathogenetic state in bronchial asthma attacks.

Asthma exacerbations. 2: aetiology

The natural history of asthma involves relatively stable periods that are often punctuated by significant exacerbations of symptoms. There are many aetiologies that may lead to an increase in asthma severity including respiratory infection (bacterial/viral), allergens, irritants, and occupational exposures. Each trigger probably acts through different mechanisms, but a final common pathway of multicellular inflammation, enhanced bronchial responsiveness, and airflow obstruction is a likely consequence. This review discusses the most common causes of asthma exacerbations with a focus on their microbiology and immunopathogenesis. Through an understanding of underlying causes of asthma exacerbations, treatments with increased effectiveness may be developed, and it is these future developments that may directly influence the morbidity and mortality of the disease.

Atopy in Patients with Bronchiectasis: More than Coincidence

Bronchiectasis is common in developing countries, but its precise underlying mechanism can be detected in only about 40% of the cases. The studies reporting the frequency of atopy and its relation to radiological findings and lung function in bronchiectasis are limited in number, and the results are controversial. The present study was designed to investigate the relationship between atopy and bronchiectasis by means of high resolution computed tomography (HRCT) and pulmonary function tests. Skin prick test, HRCT and pulmonary function tests, including spirometric values of forced expiratory volume in one second (FEV1), FEV1/FVC (forced vital capacity) ratio were performed in 121 bronchiectatic patients of unknown etiology and in 68 healthy controls. Atopy and HRCT scores for the severity of atopy and extent of bronchiectasis respectively were determined for each patient. The rate of atopy (48.8% vs 11.8%) and mean atopy score (14.3 +/- 10.1 mm vs 5.5 +/- 2.1 mm) were significantly higher in patients with bronchiectasis than those in controls. Atopic patients had significantly worse spirometric values and more extended bronchiectasis than non-atopics. There is a significant correlation between atopy and HRCT scores (r = 0.54, p < 0.001), indicating that the more severe atopy is the more extended bronchiectasis. In conclusion, we suggest that the rate of atopy is higher in bronchiectatic patients than that in healthy controls. Bronchiectatic patients with atopy have lower spirometric values and higher HRCT scores. Atopy might be considered as a deteriorating and/or a causative or contributing factor for development of bronchiectasis.

Immune dysregulation in allergic respiratory disease: the role of T regulatory cells

Although earlier research focused on the role of the polarity of T helper cell signalling as the defining factor in immune responses, it is now recognised that other cells with regulatory properties have a more key role. It has been recently proposed that allergic disease may result from an inappropriate balance between regulatory cells (including but not limited to CD4+ CD25+ T regulatory cells) and T helper type 2 (Th2) effector cells. In the airways, a number of other cells also have important regulatory effects on local immune responses, including epithelial cells and airway dendritic cells (DC). Allergic respiratory disease appears to be the culmination of both local epithelial dysfunction and generalised immune dysregulation resulting in Th2 propensity (atopic predisposition). Although these processes are related they also appear to occur independently. This review examines evolving models of allergy pathogenesis, including the newly recognised role of diverse groups of regulatory cells. Increasing rates of allergic disease (and other immune diseases) suggest that environmental changes may be having fundamental effects on common regulatory pathways. Understanding these influences and their mechanism of action could lead to strategies to prevent disease.

Interleukin-10 gene expression in acute virus-induced asthma

RATIONALE

Virus-induced asthma is characterized by marked neutrophil influx and eosinophil degranulation, suggesting a mode of immunopathogenesis different from that of allergen-induced asthma.

OBJECTIVES

This study compared induced sputum cytokine responses in subjects with severe asthma exacerbation and respiratory virus infection with those of patients with stable asthma, healthy control subjects, and virus-infected nonasthmatic subjects.

METHODS

Subject infection status and pulmonary history were established on the basis of common cold and asthma questionnaires, and lung function and atopy tests were performed. Respiratory virus infection was diagnosed by cell culture and direct polymerase chain reaction, using induced sputum. The induced sputum cellular profile was examined and cytokine gene expression was assessed by quantitative real-time polymerase chain reaction.

RESULTS

A respiratory virus was detected in 78% of subjects with acute asthma. Specific viruses detected were rhinovirus (83%), influenza (15%), enterovirus (4%), and respiratory syncytial virus (2%). Virus-infected subjects with acute asthma or no asthma had increased RANTES (regulated on activation, normal T cell expressed and secreted) and macrophage inflammatory protein-1alpha messenger RNAs compared with other groups. Interleukin (IL)-10 mRNA was significantly increased in virus-infected acute asthma and reduced on recovery from acute asthma. IL-5, eotaxin, and IL-8 mRNA transcripts were similar across groups.

CONCLUSIONS

Asthma exacerbation triggered by respiratory virus infection is characterized by increased IL-10 gene expression that may explain the suppressed eosinophil influx in acute asthma. Airway neutrophilia due to respiratory virus infection is associated with chemokine gene expression involving RANTES and macrophage inflammatory protein-1alpha.

Relationship between atopic status and nasal interleukin 10 and 11 levels in infants with respiratory syncytial virus bronchiolitis

BACKGROUND

Interleukin 10 (IL-10) and IL-11 are known to have anti-inflammatory activities, and they have been implicated in the pathogenesis of respiratory syncytial virus (RSV) infection.

OBJECTIVES

To determine IL-10, IL-11, and myeloperoxidase levels in nasal secretions of infants with acute RSV bronchiolitis and to investigate whether there are any differences in these levels in patients with vs without atopy.

METHODS

We measured IL-10, IL-11, and myeloperoxidase levels in nasal secretions of 44 infants (20 were atopic) with acute RSV bronchiolitis. The nasal secretion samples were obtained from patients at hospital admission and were stored immediately at -70 degrees C until analysis. Atopy was defined as having at least 1 positive skin prick test reaction to common allergens, a history of atopic dermatitis, or a high serum IgE level compared with age-matched controls.

RESULTS

Levels of IL-10, IL-11, and myeloperoxidase increased significantly in samples from infants with acute RSV bronchiolitis. Levels of IL-10 and IL-11 were significantly lower in patients with vs without atopy (P < .05). Myeloperoxidase levels showed no significant difference in patients with vs without atopy (P = .18). Patients with severe symptoms tended to have lower IL-10 levels (P = .09), but no relationship was shown between symptom severity and IL-11 levels. Nasal myeloperoxidase levels were significantly higher in patients with severe symptoms (P < .05).

CONCLUSIONS

Production of IL-10 and IL-11 was significantly lower in patients with vs without atopy during acute RSV bronchiolitis. The airway inflammation induced by RSV infection may be different in patients with vs without atopy, and this is associated with lower induction of these immunoregulatory cytokines in children with atopy.

Reduced nasal IL-10 and enhanced TNFalpha responses during rhinovirus and RSV-induced upper respiratory tract infection in atopic and non-atopic infants

Rhinovirus and respiratory syncytial virus (RSV) are the most prevalent inducers of upper respiratory tract infections (URTI) in infants and may stimulate immune maturation. To estimate the amount of immune stimulation, nasal immune responses were examined during rhinovirus and RSV‐induced URTI in infants. Nasal brush samples were taken from infants (2–26 months; 57% atopic family) with rhinovirus‐induced URTI (N = 20), with RSV‐induced URTI (N = 7), and with rhinovirus‐induced rhinitis (N = 11), from children with asymptomatic rhinovirus infection (N = 7) and from eight non‐infected children. Numbers of nasal brush cells positive for Th1‐, Th2‐, regulatory and proinflammatory cytokines were measured by immunohistochemistry or by measuring protein levels using a cytometric bead array analysis. During rhinovirus and RSV‐induced URTI, fewer regulatory cytokine IL‐10 positive cells were found compared to non‐infected children. This fall was accompanied by an increase in levels of the Th1 cytokine TNFα. IL‐10 responses were inversely related to TNFα responses. No enhanced responses were observed for IFNγ, IL‐12 and IL‐18. Cytokine responses were comparable in children with rhinovirus‐induced URTI and in children with rhinitis, while responses in asymptomatic rhinovirus‐infected children were located between those for symptomatic and asymptomatic rhinovirus‐infected children. Cytokine responses did not depend on the age of the child or atopy in the family. In conclusion, reduced nasal IL‐10 responses during URTI in infants could facilitate the induction of a TNFα response. TNFα in turn could replace the immature production of IL‐12, IL‐18 and IFNγ during URTI to induce an effective clearance of the viral infection and which could stimulate the maturation of Th1 cytokine production in infancy. J. Med. Virol. 75:348–357, 2005. © 2004 Wiley‐Liss, Inc.

DNA, the immune system, and atopic disease

The prevalence and severity of atopic diseases (atopic dermatitis, asthma, and allergic rhinitis) have increased over recent decades, particularly in industrialized nations. Atopic dermatitis, like asthma, is more common in older siblings and in less crowded houses and with late entry to day care, increased maternal education, and higher socio-economic status. The inverse relationship between the incidence of atopy and childhood infections has led to the "hygiene hypothesis," which suggests that diminished exposure to childhood infections in modern society has led to decreased TH1-type responses. Reduced TH1 may lead to enhanced TH2-type inflammation, which is important in promoting asthma and allergic disease. Corticosteroids, commonly used to treat these conditions, inhibit the function of inflammatory cells, but they are ineffective in altering the initial TH2-type response to allergens in a sensitized individual. Treatment with TH1 cytokines not only has failed to make any significant impact on the outcome of these diseases, but it also has caused significant adverse reactions. A novel therapeutic approach, recently reported in the preclinical setting, is the use of oligodeoxynucleotides, which contain unmethylated motifs centered on CG dinucleotides. These CpG oligodeoxynucleotides potently induce TH1 cytokines and suppress TH2 cytokines, and can prevent manifestations of asthma and other allergic diseases in animal models. They have the potential to reverse TH2-type responses to allergens and thus restore balance to the immune system without the adverse effects of TH1 cytokines.

Double-stranded RNA activates RANTES gene transcription through co-operation of nuclear factor-kappaB and interferon regulatory factors in human airway epithelial cells

BACKGROUND

Regulated on activation, normal T cells expressed and secreted (RANTES) is a member of the CC chemokine family and contributes to viral-induced airway inflammation including exacerbations of asthma. Double-stranded RNA (dsRNA) is known to be synthesized during replication of many viruses and a ligand of Toll-like receptor 3. We hypothesized that dsRNA may mimic viral infection and induce RANTES expression in airway epithelial cells.

OBJECTIVE

We first confirmed that dsRNA up-regulated RANTES mRNA and protein synthesis in the airway epithelial cells. We next focused our studies on the transcriptional regulation of RANTES.

METHODS

Airway epithelial cell line BEAS-2B and normal human bronchial epithelial cells were used in vitro study. Levels of RANTES mRNA and protein expression were determined with RT-PCR and ELISA. Mechanisms of transcriptional regulation were assessed by electrophoretic mobility shift assay and dual luciferase assay using RANTES promoter-luciferase reporter plasmids.

RESULTS

Activation of nuclear factor-kappaB (NF-kappaB) was confirmed by nuclear protein binding to a DNA probe derived from the RANTES promoter. Activity of the RANTES promoter was increased by dsRNA. The stimulation with dsRNA was partially inhibited in plasmids mutated at either of the binding sites for NF-kappaB or IFN regulatory factors (IRFs). When both sites were mutated, the activation was totally abrogated.

CONCLUSION

These results imply that dsRNA activates NF-kappaB and IRFs and these transcription factors activate transcription of the RANTES promoter and its protein expression in airway epithelial cells.

Nasal mucosa in natural colds: effects of allergic rhinitis and susceptibility to recurrent sinusitis

The mechanisms of virus-induced airway hyperresponsiveness in asthma and allergy and the failure of host defence in patients suffering from secondary airway infections are still largely unknown. The aim of this study was to examine whether the presence of allergic rhinitis or susceptibility to recurrent sinusitis affects the structural and cellular changes in nasal mucosa during natural colds and convalescence. We compared the mucosal changes in biopsy samples during acute natural colds (days 2-4 of illness) and convalescence (3 weeks later) in patients with allergic rhinitis (n = 9), patients with susceptibility to sinusitis (n = 19) and healthy controls (n = 20). We saw similarly increased numbers of mucosal T and B lymphocytes and mast cells and increased vascular density during the acute colds compared to convalescence in all the three groups. The allergic subjects had elevated levels of eosinophils in the acute phase (P = 0.03), and the allergic and sinusitis-prone subjects had elevated levels of epithelial T cells (P = 0.04) and low levels of mast cells (P = 0.005) in convalescence compared to the control group. The sinusitis-prone subjects lacked intraepithelial cytotoxic cells in convalescence. In the allergic subjects, the reticular basement membrane was thicker in the acute phase compared to the convalescence (P = 0.05). These results suggest that various cells of the airways, including inflammatory and structural cells, are involved during viral respiratory infections in subjects with allergic rhinitis. The small numbers of mast cells and cytotoxic lymphocytes in the sinusitis-prone subjects may be related to their susceptibility to bacterial complications.

Diminished dendritic cell interleukin 10 production in atopic children

BACKGROUND

Diminished interleukin 10 (IL-10) and/or IL-12 production may contribute to the pathogenesis of asthma and atopy. Dendritic cells (DCs) produce these cytokines and have been implicated in the pathogenesis of these disorders.

OBJECTIVE

To determine whether DC IL-10 and/or IL-12 production is diminished in children aged 6 to 12 years with allergic rhinitis (AR) and with or without asthma.

METHODS

Monocyte-derived DCs were isolated from 20 subjects without AR or asthma (group 1), 20 subjects with AR without asthma (group 2), and 20 subjects with AR and asthma (group 3). Asthma was defined as a history of physician-diagnosed disease, and AR was defined as a positive history and positive puncture skin test responses (wheal > or = 5 mm) to relevant inhalant allergens. DCs were stimulated with either lipopolysaccharide (LPS) or diluent and cultured for 24 hours. Supernatants were assayed for IL-10 and IL-12 levels by enzyme-linked immunosorbent assay.

RESULTS

DC IL-10 production was diminished in groups 2 and 3 compared with group 1. Median LPS-induced IL-10 levels were 11.0 pg/mL in group 1, 6.1 pg/mL in group 2, and 1.5 pg/mL in group 3. The frequencies of subjects with detectable IL-10 levels were 85%, 20%, and 20% in groups 1, 2 and 3, respectively. Median LPS-induced IL-12 levels were similar in all groups.

CONCLUSIONS

These data support the hypothesis that atopic subjects have an intrinsic inability to up-regulate DC IL-10 production. Future studies in this area could lead to a better understanding of the pathogenesis of atopy.

Cytokine secretion in nasal mucus of normal subjects and patients with allergic rhinitis

Allergic rhinitis is regulated by the local production and release of several cytokines. The levels of Th2 cytokines IL-4, IL-6, IL-10 and the Th1 cytokine IFN-gamma were studied in nasal mucus from 30 subjects with allergic rhinitis and 45 non-atopic healthy controls. In this study a sampling technique for collecting nasal mucus, well tolerated by the subjects and with a minimal stimulation of the mucosa, was performed. The cytokine concentrations in nasal mucus samples were detected and quantitated by a new paramagnetic particle-based immunofluorescent assay system more sensitive than the conventional ELISA techniques. The new technique showed reliable values of the measured parameters. The nasal mucus from allergic patients contained significantly higher concentrations of IL-4 (25.5 +/- 3.6 pg/ml; P < 0.001) and IL-10 (1300 +/- 190 pg/ml; P < 0.05) compared to the nasal mucus from control subjects (15.2 +/- 2.3 and 532 +/- 28 pg/ml, respectively, for IL-4 and IL-10). No significant modification in IFN-gamma levels of allergic patients was found when compared to control group (respectively, 19.9 +/- 3.3 vs. 25.7 +/- 5.1 pg/ml; P > 0.05). Moreover, the allergic patients showed lower levels of IL-6 concentrations in the nasal mucus compared to control subjects (64.8 +/- 9.1 vs. 129.0 +/- 18.1 pg/ml; P = 0.0099). These data can be interpreted by the hypothesis that in response to environmental allergens there is a preferential Th2 polarity by activated CD4+ T cells and that the cytokines IL-6 and IL-10 have, respectively, an important anti-inflammatory and counterregulatory action in the pathogenesis of allergic rhinitis.

Association between environmental tobacco smoke and diminished dendritic cell interleukin 10 production during infancy

BACKGROUND

Diminished interleukin 10 (IL-10) production has been documented in children and adults with asthma and atopy. Environmental tobacco smoke (ETS) is recognized as a risk factor for the development of childhood asthma.

OBJECTIVE

To determine whether there is an association between ETS and dendric cell (DC) IL-10 production during infancy.

METHODS

ETS was evaluated by questionnaire, and blood samples were obtained at 2 weeks, 3 months, and 5 months of age in 37 healthy infants. DCs were cultured and stimulated, and supernatants were assayed for IL-10 by enzyme immunoassay.

RESULTS

Sixteen infants had no history of exposure to ETS, and 21 infants had a history of ETS exposure. The frequency of subjects with detectable IL-10 levels was similar in both groups at 2 weeks and 3 months but significantly different at 5 months (P < .001). In those without ETS exposure, the frequency with detectable IL-10 levels increased during the observation period (25% at 2 weeks, 20% at 3 months, and 36% at 5 months; P = .03 vs 2 weeks). In contrast, in those with ETS exposure, the frequency with detectable IL-10 levels decreased during the observation period (33% at 2 weeks, 19% at 3 months; P = .02 vs 2 weeks; and 7% at 5 months; P < .001 vs 2 weeks).

CONCLUSIONS

Our study results demonstrate an association between ETS and diminished DC IL-10 production during infancy. Future studies need to expand on these sample sizes and explore whether diminished DC IL-10 production is the mechanism by which ETS predisposes patients to the development of asthma and/or atopy.

Increasing prevalence of allergic rhinitis but not asthma among children in Hong Kong from 1995 to 2001 (Phase 3 International Study of Asthma and Allergies in Childhood)

There is a worldwide belief that the prevalence of asthma and other allergic diseases is increasing but the measures used in many studies are susceptible to systematic errors. We examined the trend of asthma, allergic rhinitis and eczema prevalence in school children aged 6-7 years in Hong Kong from 1995 to 2001 using standardized ISAAC methodology. There were 4448 and 3618 children participating in 2001 and 1995, respectively. The prevalence of life-time rhinitis (42.4% vs. 38.9%, p < 0.01), current rhinitis (37.4% vs. 35.1%, p < 0.03), current rhinoconjunctivitis (17.2 vs. 13.6%, p < 0.01) and life-time eczema (30.7% vs. 28.1%, p = 0.01) increased significantly. There was no significant change in prevalence of life-time asthma, life-time wheeze and current wheeze albeit a significant increase in severe asthma symptoms. We investigated a number of potential risk factors including sex, family history of atopy, sibship size, birth weight, respiratory tract infections, pet ownership and exposure to tobacco smoke. However, the increases in prevalence of rhinitis and eczema could not be entirely explained by the change of prevalence of these risk factors. The odds ratio OR for the study period remained significantly associated with current rhinitis (OR 1.31, 95% confidence intervals CI 1.17-1.46), current rhinoconjunctivitis (OR 1.63, 95% CI 1.41-1.87) and life-time eczema (OR 1.30, 95% CI 1.16-1.45) after adjustment for these confounding variables using logistic regression model. Further study is warranted to elucidate the factors contributing to the observable change in the prevalence of rhinitis in our population.

Paranasal sinus bony structures and sinus functioning during viral colds in subjects with and without a history of recurrent sinusitis

OBJECTIVES/HYPOTHESIS

The objective was to assess the impact of ostial obstruction and anatomical variations on paranasal sinus functioning during viral colds with computed tomography (CT) in subjects with and without a history of sinusitis.

STUDY DESIGN

Cross-sectional study.

METHODS

Twenty-three volunteers with a history of recurrent sinusitis and 25 subjects without such history who had an early (symptoms for 2-4 d) natural cold were examined by taking viral specimens and CT scans and recording symptoms. The pathological sinus changes in the CT scans were scored, and several paranasal bony anatomical variations recorded.

RESULTS

Viral origin of the cold was identified in 32 (67%) subjects, similarly in the two groups. Ostiomeatal obstruction and anatomical variations were equally frequent in the subjects with and without a sinusitis history (17 of 23 vs. 17 of 25 for ostial obstruction and 17 of 23 vs. 20 of 25 for at least one variation, respectively). However, in the case of ostiomeatal obstruction the combined CT score of ethmoidal and maxillary sinuses was significantly higher in the subjects with a sinusitis history than in those without (mean +/- SD, 3.0 +/- 0.9 vs. 2.3 +/- 1.2 [P =.05, t test]). In the sinusitis-prone subjects, several variations were associated significantly with various pathological sinus CT changes (septal deviation, horizontally situated processus uncinatus, large concha bullosa, and laterally concave concha media), whereas in the control subjects, only the presence of Haller cells was related to sphenoidal sinus disease.

CONCLUSION

Ostiomeatal complex obstruction and bony anatomical variations seem to have a greater impact on the functioning of paranasal sinuses during viral colds in sinusitis-prone subjects than in subjects without a sinusitis history. These differences may be associated with the increased risk of bacterial sinusitis.

New concepts of cytokines in asthma: is the Th2/Th1 paradigm out the window?

Although asthma is clearly associated with a systemic propensity for allergic T helper type 2 (Th2) cell cytokine responses, independent local immune events appear to be responsible for the development of allergic airways inflammation. There is growing interest in how local immune networks interact with resident airway cell populations such as epithelial cells, which are now also recognized as key producers of cytokines, chemokines and growth factors. As well as their recognized role in airway remodelling, epithelial cells are now thought to have a role in initiating events. This review examines the role of cytokines produced by these and other cells in the development of asthma. It also highlights emerging concepts that the excessive and inappropriate immune responses seen in allergic disease may be related to dysfunction of various interleukin-10 producing regulatory cell populations.

Is asthma an infectious disease?: Thomas A. Neff lecture

Respiratory tract infections caused by viruses, Chlamydia, and Mycoplasma have been implicated in the pathogenesis of asthma. Of these respiratory pathogens, viruses have been demonstrated to be associated with asthma epidemiologically in at least two ways. First, during infancy, certain viruses have been implicated as potentially being responsible for the inception of the asthmatic phenotype. Second, in patients with established asthma, particularly children, viral upper respiratory tract infections play a significant role in producing acute exacerbations of airway obstruction that may result in frequent outpatient visits or in hospitalizations. For infections with other microbial agents, recent attention has focused on Chlamydia and Mycoplasma as potential contributors to both exacerbations and the severity of chronic asthma in terms of loss of lung function or medication requirements. In an attempt to address the question posed in the title, this article will briefly review these various associations as they pertain to the pathogenesis of asthma in both children and adults.

Lymphocyte and mast cell counts are increased in the nasal mucosa in symptomatic natural colds

Knowledge of the virus-induced immune response is important in understanding the pathophysiology of respiratory virus infections. Data on the cellular immune response is still limited and based mainly on experimental studies. Natural colds may differ in their pathophysiology from experimentally induced ones. To evaluate the inflammatory cell responses in the upper respiratory tract during natural colds we counted the number of lymphocytes, mast cells and macrophages in the nasal mucosa. Nasal biopsies were taken from 22 adult volunteers during the acute (2-4 days of symptoms) and convalescent phases (day 21) of the cold, and the numbers of cells were counted with immunohistochemical methods. Viral aetiology was identified in 14 (64%) subjects by using viral isolation, antigen detection and rhino-polymerase chain reaction assays. The number of T lymphocytes was increased in the nasal epithelium and that of T and B lymphocytes and mast cells in the subepithelial layer in the acute phase compared to the convalescent phase. Intraepithelial T lymphocyte counts were significantly higher in the subjects who had a proven viral infection or a finding of pathogenic bacteria in the nasopharynx compared to the subjects without such findings (P = 0.005 and P = 0.04, respectively). Contrary to the earlier experimental studies, we found that viruses cause accumulation of T and B lymphocytes and mast cells during the first days of a symptomatic naturally acquired respiratory infection.

Allergen-specific CD8(+) T cells and atopic disease

Considerable evidence suggests that IL-10 may have a role in the manifestation of atopic disease. We sought to test the hypothesis that at the single cell level, allergen-specific T cells have diminished IL-10 production capacity in severely affected atopics compared with asymptomatic atopics. We defined three A*0201-restricted Der p 1 CD8(+) T cell epitopes. Using human leukocyte antigen-A*0201-peptide (HLA-A*0201-peptide) tetrameric complexes and enzyme-linked immunospot assays to analyze peripheral blood mononuclear cells from A*0201-positive severely symptomatic atopics, asymptomatic atopics, and nonatopic controls, we observed a significant association between the frequency of the Der p 1-specific CD8(+) T cells and disease activity. The specific T cells expressed an antigen-experienced cell surface phenotype, and 45.7% were positive for cutaneous lymphocyte-associated antigen. The specific T cells were able to produce IFN-gamma efficiently, but their IL-10 production was significantly reduced in severely affected atopics. In contrast, viral-specific CD8(+) T cells were able to produce equivalent amounts of IL-10 in the severely affected atopics compared with asymptomatic atopics and nonatopics. Through defining the first human atopic allergen HLA class I epitopes, we have provided a possible cellular mechanism to link the previous association of low IL-10 levels and severe atopic disease. These data are consistent with a role for CD8(+) T cells in atopic disease pathogenesis and may provide a basis for future T cell immunotherapy strategies.

Transgenic overexpression of interleukin (IL)-10 in the lung causes mucus metaplasia, tissue inflammation, and airway remodeling via IL-13-dependent and -independent pathways

To address the complex chronic effector properties of interleukin (IL)-10, we generated transgenic mice in which IL-10 was overexpressed in the lung. In these mice, IL-10 inhibited endotoxin-induced tumor necrosis factor production and neutrophil accumulation. IL-10 also caused mucus metaplasia, B and T cell-rich inflammation, and subepithelial fibrosis and augmented the levels of mRNA encoding Gob-5, mucins, and IL-13. In mice bred to have null mutations of IL-13, IL-4R(alpha), or STAT-6, transgenic IL-10 did not induce mucus metaplasia but did induce inflammation and fibrosis. IL-10 was also a critical mucin regulator of virus-induced mucus metaplasia. Thus, IL-10, although inhibiting lipopolysaccharide-induced inflammation, also causes mucus metaplasia, tissue inflammation, and airway fibrosis. These responses are mediated by multiple mechanisms with mucus metaplasia being dependent on and the inflammation and fibrosis being independent of an IL-13/IL-4R(alpha)/STAT-6 activation pathway.

Association of rhinovirus infection with increased disease severity in acute bronchiolitis

Respiratory syncytial virus (RSV) is the major pathogen responsible for acute bronchiolitis in infancy. However, evaluation of the relative importance of rhinovirus or multiple viral infections has been hampered by the lack of sensitive diagnostic methodologies. Therefore, in this study we used the reverse transcription-polymerase chain reaction for 11 respiratory pathogens to assess the etiology in infants with acute bronchiolitis and correlate it with clinical characteristics of the disease. Viruses were detected in 73.7% of patients. RSV was identified in 72.4% of virologically confirmed cases, rhinovirus in 29%, whereas multiple infections represented 19.5% of cases, most of which (69%) were combinations of rhinovirus with RSV. In a logistic regression model controlling for age, sex, birth weight, presence of fever, and day of disease on admission, the presence of rhinovirus was found to increase by approximately five-fold, the risk for severe disease. Multiple pathogens had a similar trend in the univariate analysis, which was eliminated in the multivariate model. Multiple virus cases were admitted to the hospital later in the course of their disease than unique pathogen cases, suggesting successive infections. In conclusion, rhinovirus is second only to RSV as a causative agent of bronchiolitis and is associated with more severe disease. The presence of more than one pathogen may influence the natural history of acute bronchiolitis.

Infections

Infection, in particular by respiratory viruses, plays an important role in triggering exacerbations and has also been implicated in the etiology of asthma and chronic obstructive pulmonary disease (COPD). This chapter reviews the epidemiological evidence that implicates infectious pathogens as triggers. The chapter also discusses the mechanisms of interaction between the host-pathogen response and preexisting airway pathology resulting in an exacerbation. Much of the treatment of infective exacerbations for both asthma and COPD is symptomatic, consisting of bronchodilators or supportive in the form of oxygen, and in severe cases it includes noninvasive or invasive ventilatory measures. The current therapy for virus-induced exacerbations of asthma and COPD relies on increased treatment of preexisting disease. Antibiotics are indicated for bacterial infections. The effective use of antiviral agents, particularly for influenza viruses, requires viral diagnosis, commencement of treatment early in the course of an exacerbation, or the targeting of high-risk groups for prophylaxis. Alternative strategies for drug development involve the identification of key factors common to exacerbations induced by a range of different viruses. Increased knowledge of the host–virus interaction can help in designing treatments that can increase virus clearance and minimize immunopathology.