Bronchial responsiveness to methacholine is increased in citrus red mite (Panonychus citri)-sensitive children without asthmatic symptoms

Epidemiology of spider mite sensitivity: a meta-analysis and systematic review

Background

Spider mites, including Tetranychus urticae, Panonychus citri, and Panonychus ulmi, are common pests in gardens, greenhouses, and orchards. Exposure, particularly occupational exposure, to these organisms may lead to the development of respiratory or contact allergies. However, the prevalence of sensitivity to spider mites is unclear.

Methods

We examined the literature to generate an estimate of the global prevalence of allergies to spider mites.

Results

Electronic databases were searched and twenty-three studies reporting the prevalence of sensitivity to spider mites (based on skin prick tests or IgE-based detection systems) in an aggregate total of 40,908 subjects were selected for analysis. The estimated overall rate of spider mite sensitivity was 22.9% (95% CI 19–26.8%). Heterogeneity was high and meta-regression analysis considering variables such as published year, country, number of study subjects, methods for allergen detection (skin prick test, ImmunoCAP, RAST testing, or intradermal test), and mite species revealed no single significant source. Twelve of the 23 studies reported rates of monosensitization (i.e., patients responsive to spider mites but no other tested allergen), yielding a global average of 7% (95% CI 5–9%), hence spider mites represent a unique source of allergens.

Conclusions

Spider mites are an important cause of allergic symptoms. However, the publication bias and heterogeneity evident in this study indicate that further trials using standardized detection methods are needed to determine the association of exposure and symptoms as well as the specific patient characteristics that influence developing spider mite sensitivity.

What makes a difference in exercise-induced bronchoconstriction: an 8 year retrospective analysis

Background

Exercise-induced bronchoconstriction (EIB) was recently classified into EIB alone and EIB with asthma, based on the presence of concurrent asthma.

Objective

Differences between EIB alone and EIB with asthma have not been fully described.

Methods

We retrospectively reviewed who visited an allergy clinic for respiratory symptoms after exercise and underwent exercise bronchial provocation testing. More than a 15% decrease of forced expiratory volume in 1 second (FEV1) from baseline to the end of a 6 min free-running challenge test was interpreted as positive EIB.

Results

EIB was observed in 66.9% of the study subjects (89/133). EIB-positive subjects showed higher positivity to methacholine provocation testing (61.4% vs. 18.9%, p<0.001) compared with EIB-negative subjects. In addition, sputum eosinophilia was more frequently observed in EIB-positive subjects than in EIB-negative subjects (56% vs. 23.5%, p = 0.037). The temperature and relative humidity on exercise test day were significantly related with the EIB-positive rate. Positive EIB status was correlated with both temperature (p = 0.001) and relative humidity (p = 0.038) in the methacholine-negative EIB group while such a correlation was not observed in the methacholine-positive EIB group. In the methacholine-positive EIB group the time to reach a 15% decrease in FEV1 during exercise was significantly shorter than that in the methacholine-negative EIB group (3.2±0.7 min vs. 8.6±1.6 min, p = 0.004).

Conclusions

EIB alone may be a distinct clinical entity from EIB with asthma. Conditions such as temperature and humidity should be considered when performing exercise tests, especially in subjects with EIB alone.

Differences in airway inflammation according to atopic status in patients with chronic rhinitis

Background

Chronic rhinitis is a heterogeneous group of diseases that cause nasal inflammation. And the nose may be a window into the lung in the concept of "one airway one disease."

Objective

This study was conducted to evaluate differences between the different forms of chronic rhinitis in terms of lower airway inflammation.

Methods

Patients that attended the allergy clinic and presented with moderate/severe persistent rhinitis symptoms for more than 1 year were enrolled. The patients with chronic rhinitis were classified into two groups (house dust mites [HDM]-sensitive allergic rhinitis [AR] or non-allergic rhinitis [NAR]) according to the presence of atopy, and additionally according to nasal polyposis and airway hyperresponsiveness, respectively. Medical records were reviewed and the mRNA expression levels of IL-5, IFN-γ, TGF-β1, IL-17A, and IL-25 were evaluated in induced sputum samples in each group.

Results

Induced sputum samples of 53 patients were evaluated. Patients with NAR were significantly older than patients with HDM-sensitive AR (p < 0.05). Nasal polyposis was more prevalent in NAR patients than in HDM-sensitive AR patients (10.2% vs. 62.5%, p < 0.001). The expression levels of IL-17A mRNA were higher in NAR patients, regardless of the presence of airway hyperresponsiveness (p = 0.005).

Conclusion

These results suggest that patients with different forms of chronic rhinitis could have different inflammatory environments in their lower airway and NAR patients might have bronchial inflammation related to the elevated levels of IL-17A compared to HDM-sensitive AR patients.

Evaluation of cytokine mRNA in induced sputum from patients with allergic rhinitis: relationship to airway hyperresponsiveness

BACKGROUND

Although airway hyperresponsiveness (AHR) is a characteristic feature of asthma, it is also frequently present in allergic rhinitis (AR). However, the pathogenesis of AHR is unclear and the roles of cytokines in the airway have not been well established in AR. We sought to compare cytokine mRNA levels in the sputum of AR patients with or without AHR and those of asthma patients, and to evaluate whether differences in cytokine levels are associated with the development of an abnormal airway response and the absence of respiratory symptoms in AR patients with AHR.

METHODS

Airway cells were obtained by sputum induction from 18 AR patients with AHR, 58 AR patients without AHR, and 27 asthma patients. Airway cell cytokine levels, interleukin (IL) -4, IL-5, IL-13, vascular endothelial growth factor (VEGF), and interferon-gamma (IFN-gamma), were studied at the mRNA level by RT-PCR.

RESULTS

Vascular endothelial growth factor and IL-5 mRNA levels were significantly higher in AR patients with AHR than in AR patients without AHR, but these were lower than those of asthmatic patients. Eosinophils were significantly higher in AR patients with AHR and in asthmatic patients than in AR patients without AHR. Interleukin-4, IL-13, and IFN-gamma levels were not elevated in AR patients with or without AHR vs asthma patients.

CONCLUSIONS

These findings suggest that VEGF and IL-5 can be important determinants of the development of AHR in AR patients and that lower levels of other cytokines may be associated with the absence of asthmatic symptoms in AR patients with AHR.

Association between sensitization to outdoor spider mites and clinical manifestations of asthma and rhinitis in the general population of adults

It has been demonstrated that spider mites such as the two-spotted spider mite (Tetranychus urticae) are important allergens for fruit farmers. A total of 2,467 adults (795 metropolitan urban, 788 non-metropolitan urban, and 884 rural subjects) were enrolled. They responded to the questionnaire, and underwent methacholine bronchial provocation tests as well as skin prick tests to locally common aeroallergens including the two-spotted spider mite. The prevalences of asthma and rhinitis as reported on the questionnaire were 7.8% and 16.4% of adults aged 20-35, 9.4% and 24.7% of those 36-50, and 17.7% and 21.7% of those older than 50, respectively. Among the older group, the two-spotted spider mite was the most common sensitizing allergen, although it was second of that of house dust mites among the other two age groups. Sensitization to the two-spotted spider mite was significantly associated with the prevalence of asthma and rhinitis among the younger age group, and associated with the prevalence of rhinitis among the older age group. The two-spotted spider mite might be a common sensitizing allergen in the general population of adults, and sensitization to this mite may play a role in the manifestation of asthma and rhinitis symptoms during adulthood.

High prevalence of current asthma and active smoking effect among the elderly

BACKGROUND

Although asthma is a common cause of morbidity in adults, relatively few objectively measured population studies of asthma prevalence in adult populations have been conducted.

OBJECTIVE

To evaluate the prevalence of asthma, based on both a questionnaire and methacholine bronchial provocation test, and to determine the risk factors of asthma prevalence in an adult population.

METHODS

A total of 2,467 adults, who were randomly selected from metropolitan urban, non-metropolitan urban and rural areas, responded to the modified ISAAC questionnaire, and underwent methacholine bronchial provocation tests and skin prick tests to locally common aeroallergens.

RESULTS

The prevalence of current asthma based on the questionnaire and the methacholine challenge was 2.0% in adults younger than 40, 3.8% in 40- to 54-year-olds, 7.7% in 55- to 64-year-olds and 12.7% in those aged 65 or higher. For subjects of 55-64 years, active smoking was found to be significantly related with the prevalence of current asthma and bronchial hyper-responsiveness, although smoking was positively associated with percentage predictive value of forced expiratory volume of 1 s (FEV1).

CONCLUSION

The prevalence of current asthma is common among the elderly, and active smoking may play an important role in the development of asthma and bronchial hyper-responsiveness among the elderly.

Role of environmental exposure to spider mites in the sensitization and the clinical manifestation of asthma and rhinitis in children and adolescents living in rural and urban areas

BACKGROUND

Spider mites such as the citrus red mite and the two-spotted spider mite have been demonstrated to be important allergens for fruit cultivating farmers.

OBJECTIVE

To evaluate the role of environmental exposure to spider mites in the sensitization and the clinical manifestations of asthma and rhinitis in children and adolescents living in urban and rural areas.

METHODS

A total of 16,624 subjects (aged 7 to 18 years) living in urban (metropolitan and non-metropolitan) and rural areas (apple orchards and citrus orchards) in Korea were evaluated by questionnaire and skin prick test for 11 common aeroallergens, including citrus red mite (CRM) and two-spotted spider mite (TSM).

RESULTS

The positive skin response rates to TSM were 4.2% of 1,563 metropolitan subjects, 3.8% of 5,568 non-metropolitan subjects and 6.5% of 1,464 subjects living nearby apple farms, and that to CRM 15.6% of 8,029 living nearby citrus farms. The prevalence of current wheeze and rhinitis as reported on a questionnaire was higher among those with a history of visiting fruit farms once or more per year than among those without it (10% vs. 7.1%, 32.8% vs. 26.7%, for wheezing and rhinitis, respectively). Among those with wheezing or rhinitis, the positive skin responses to TSM or CRM were also higher among those with a history of visiting fruit farms than among those without one (11.2% vs. 6.6%, 13.0% vs. 6.6%, respectively), although the positive skin responses to house dust mites were similar in the both groups.

CONCLUSION

Spider mites are common sensitizing allergens in children and adolescents exposed to them, and environmental exposure to these mites may represent an important risk factor in the sensitization and the clinical manifestations of asthma and rhinitis in children and adolescents living in rural and urban areas.

Spider-mite allergy and asthma in fruit growers

Asthma and allergic diseases caused by domestic mites such as house dust mites and storage mites are major health problems worldwide. In contrast to domestic mites, spider mites are outdoor phytophagous mites causing significant damage to fruit leaves throughout the world. After several case reports of spider mite-induced asthma and allergy, cross-sectional surveys have demonstrated that spider mites are important allergens in the development of asthma and rhinitis in fruit farmers. Interestingly, epidemiological surveys have also demonstrated that spider mites are common sensitizing allergens that are related to the prevalence of asthma and rhinitis, even in the non-farming population exposed to spider mites. Protein analysis has demonstrated that crude extracts derived from spider mites contain several major allergens, and that N-terminal amino acid sequencing of the major allergens is not homologous with any previously characterized domestic mite allergens, suggesting that major allergens derived from spider mites are unique in terms of cross-reactivity to domestic mites. Taken together, these findings suggest that spider mites are important allergens in the development of asthma among the exposed non-farming population as well as among fruit farmers themselves, and that allergens derived from spider mites may be novel allergens.