Severe airway hyperresponsiveness was not predictable with the use of current tools in asthmatic children in general practice

A 7-Amino Acid Peptide Mimic from Hepatitis C Virus Hypervariable Region 1 Inhibits Mouse Lung Th9 Cell Differentiation by Blocking CD81 Signaling during Allergic Lung Inflammation

T helper (Th) cells orchestrate allergic lung inflammation in asthma pathogenesis. Th9 is a novel Th cell subset that mainly produces IL-9, a potent proinflammatory cytokine in asthma. A 7-amino acid peptide (7P) of the hypervariable region 1 (HVR1) of hepatitis C virus has been identified as an important regulator in the type 2 cytokine (IL-4, IL-5, and IL-13) immune response. However, it is unknown whether 7P regulates Th9 cell differentiation during ovalbumin- (OVA-) induced allergic lung inflammation. To address this, we studied wild-type mice treated with 7P and a control peptide in an in vivo mouse model of OVA-induced allergic inflammation and an in vitro cell model of Th9 differentiation, using flow cytometry, cytokine assays, and quantitative PCR. The binding of 7P to CD81 on naïve CD4⁺ T cells during lung Th9 differentiation was determined using CD81 overexpression and siRNA knockdown analyses. Administration of 7P significantly reduced Th9 cell differentiation after OVA sensitization and exposure. 7P also inhibited Th9 cell differentiation from naïve and memory CD4⁺ T cells in vitro. Furthermore, 7P inhibited the differentiation of human Th9 cells with high CD81 expression from naïve CD4⁺ T cells by blocking CD81 signaling. CD81 siRNA significantly reduced Th9 cell differentiation from naïve CD4⁺ T cells in vitro. Interestingly, CD81 overexpression in human naïve CD4⁺ T cells also enhanced Th9 development in vitro. These data indicate that 7P may be a good candidate for reducing IL-9 production in asthma.

Monitoring asthma in childhood: lung function, bronchial responsiveness and inflammation

This review focuses on the methods available for measuring reversible airways obstruction, bronchial hyperresponsiveness (BHR) and inflammation as hallmarks of asthma, and their role in monitoring children with asthma. Persistent bronchial obstruction may occur in asymptomatic children and is considered a risk factor for severe asthma episodes and is associated with poor asthma outcome. Annual measurement of forced expiratory volume in 1 s using office based spirometry is considered useful. Other lung function measurements including the assessment of BHR may be reserved for children with possible exercise limitations, poor symptom perception and those not responding to their current treatment or with atypical asthma symptoms, and performed on a higher specialty level. To date, for most methods of measuring lung function there are no proper randomised controlled or large longitudinal studies available to establish their role in asthma management in children. Noninvasive biomarkers for monitoring inflammation in children are available, for example the measurement of exhaled nitric oxide fraction, and the assessment of induced sputum cytology or inflammatory mediators in the exhaled breath condensate. However, their role and usefulness in routine clinical practice to monitor and guide therapy remains unclear, and therefore, their use should be reserved for selected cases.

Limitations of questioning asthma to assess asthma control in general practice

BACKGROUND

The monitoring of children with asthma in primary care is based on the occurrence and frequency of asthma symptoms. We questioned whether the current approach is adequate to identify all children in whom a sufficient level of asthma control is not achieved.

AIM

The aim of this study is to illustrate that in some children asthma was incorrectly considered controlled, because the children failed to report current symptoms of asthma.

PATIENTS AND METHODS

One hundred and nineteen children were identified with recent wheezing plus moderate or severe airway hyperresponsiveness. We analyzed whether these children reported current symptoms of asthma (as normally questioned during a routine visit).

RESULTS

In 20 children (18%) current asthma symptoms were absent despite moderately or severe airway hyperresponsiveness and wheezing in the last year. In addition, the usage of controller medication was very poor.

CONCLUSION

We conclude that the general practitioner has insufficient tools to adequately assess asthma control in all children. The assessment of airway hyperresponsiveness as an additional guide to manage asthma in children in general practice is recommended. In this way, better asthma control can be achieved.

Role of airway epithelial cells in development of asthma and allergic rhinitis

Asthma and allergic rhinitis frequently coexist in the same patient. There is a similarity and variation as well as potential relationship between asthma and allergic rhinitis. There is an increasing evidence to suggest a major involvement of airway epithelial cells in the pathogenesis of asthma and allergic rhinitis. The present review describes the importance of the airway epithelial cell in the development of allergic airway diseases, its role as the primary airway defense against exposure of the airway and lung to inflammatory stimuli and antigens and as an important player through activation of epithelial Toll-like receptors (TLRs) to provide an important link between innate immunity and allergic disease. Additionally, airway epithelial cells can act as inflammatory promoters capable of directing dendritic cells (DCs) towards a T helper 2 (Th2) response, and as active producers of several inflammatory/anti-inflammatory mediators. It is hypothesized that airway epithelial cells may play as both inflammatory initiator and immuno-pathological feedback regulation between allergic rhinitis and asthma via release of systemic inflammatory mediators. Thus, airway epithelial cells may be valuable therapeutic targets for discovery and development of new drugs and/or new therapeutic strategies to treat asthma and allergic rhinitis.

Residential exposure to mould and dampness is associated with adverse respiratory health

BACKGROUND

Indoor exposure to mould and dampness is frequently associated with asthma symptoms with and without lung function changes. However, the mechanisms contributing to this threat to respiratory health are only partly understood.

OBJECTIVE

To investigate the contribution of recent exposure to mould and dampness in the living room or bedroom to respiratory health in a general practice-based cohort of 526 asthmatic children.

METHODS

Parents were questioned about home characteristics, including moulds and dampness. The level of asthma control was evaluated in their participating children by means of asthma symptoms, peak expiratory flow (PEF) variability, severity of airway hyperresponsiveness (AHR), and medication usage.

RESULTS

Children exposed to indoor moulds and dampness more often had severe AHR compared with non-exposed (42% vs. 16%; P< or =0.001). They also showed an increased PEF variability (11.3% vs. 8.4%; P=0.03) and, however, not significant, more frequent asthma symptoms. The use of controller medication was not significantly different between exposed and non-exposed children. After adjustment for gender, age, smoking, exposure to parental smoking, parental education, pet ownership, presence of inhalant allergy, use of controller medication, health care center, and season of study assessment, the odds ratio for severe AHR in exposed children was 3.95 [95% confidence interval (CI): 1.82-8.57].

CONCLUSION

We found a consistent association between reported moulds and dampness in the living room or the child's bedroom and an increased risk for severe AHR in a general practice-based cohort of asthmatic children, even after adjustment for gender, presence of inhalant allergy, and use of controller medication.