Association of house dust mite-specific IgE with asthma control, medications and household pets

Correlation of Blomia tropicalis-specific immunoglobulin epsilon profiles with family history of atopy in a Filipino population

Background

House dust mites are the major source of indoor allergens in the tropical and subtropical regions with Blomia tropicalis (Bt) allergens as one of the leading causative agents of sensitization among patients from the tropics. Despite the clinical importance of Bt in various populations, its allergenicity remains unclear among Filipino allergic patients.

Objective

This study determined the sensitization profiles of allergic Filipinos against Bt allergens and its correlation with atopy.

Methods

Total immunoglobulin epsilon (IgE) (n = 960), Bt-specific IgE (n = 247), and Blomia tropicalis 5 (Blo t 5)-specific IgE (n = 87) profiles of allergic and nonallergic subjects were measured through enzyme-linked immunosorbent assay (ELISA). Point-biserial correlation coefficient was used to determine the association between Bt-specific IgE levels and selected demographics. Inhibition ELISA was performed to measure the inhibition capacity of recombinant Blo t 5 (rBlo t 5) against Bt allergen extracts.

Results

Mean total IgE levels of allergic cases (n = 171) were significantly higher (P < 0.001) compared to the mean IgE levels of nonallergic controls (n = 76). Among allergic subjects, 58% were sensitized to Blo t extract and 80% of which were sensitized to rBlo t 5 allergen. A positive correlation was observed between Bt-specific IgE and family history of atopic disease (P = 0.031). Inhibition assay revealed that 54% mean reactivity of 7 plasma samples was caused by rBlo t 5, validating that rBlo t 5 is a major allergen in Bt.

Conclusions

This study has shown the importance of Bt as an allergen source that sensitizes atopic Filipino subjects. Hence, inclusion of Bt allergen extract and rBlo t 5 in the panel for allergy diagnosis and immunotherapy in Filipino populations is strongly recommended.

Immunological Factors Associated with Adult Asthma in the Aseer Region, Southwestern Saudi Arabia

Background: The prevalence of asthma is on the rise in Saudi Arabia. Data regarding the immunological profile of asthma in adults in the Aseer region, in southwestern Saudi Arabia, have not been well studied. Objectives: Our aim was to study the immunological factors associated with sensitization to asthma among adults in the Aseer region. Methods: A cross-sectional study with a nested case control design in a 1:1 ratio was conducted on a sample of adults attending primary health care centers in the Aseer region. The study used a validated Arabic version of the International study of asthma and allergies in childhood (ISAAC) questionnaire. The presence of wheezing in the past 12 months was used as a proxy for bronchial asthma. Matched age and sex controls were selected. Both groups were tested for complete blood count (CBC), total and differential white blood cell (WBC) count including eosinophils, total immunoglobulin E (IgE) measurement, allergen-specific immunoglobulin E (IgE), and cytokine levels. Results: The present study included 110 cases and 157 age- and sex-matched controls. Rye wheat was found to be a significant outdoor sensitizing agent ((odds ratio) OR = 5.23, 95% CI: 1.06–25.69). Indoors, house dust mites Dermatophagoides petronyssinus (OR = 2.04, 95% CI: 1.04–3.99) and Dermatophagoides farinae (OR = 2.50, 95% CI: 1.09–5.75) were significant. Higher total IgE (OR = 1.84, 95% CI: 1.10–3.06) and eosinophil levels (OR = 2.85, 95% CI: 1.14–7.15) were significantly associated with adult bronchial asthma in Aseer. On the other hand, the role of cytokines was not significant. Conclusions: In the present study, certain environmental agents were found to be important with regards to sensitization to bronchial asthma in adults. Knowledge about these sensitization agents should be disseminated to health providers and treating physicians in order to enhance preventive environmental control measures and asthma management. Asthma-treating physicians in the region should be alerted to the use of targeted biological therapies in selected asthmatics with difficult-to-control courses.

A review of house dust mite allergy in India

House dust mites (HDMs) are extensively reported as potent allergens worldwide with India being in the top row. HDM sensitization is hugely reported from India and has led to the concern of implementing proper guidelines for treatment of the sufferers. Climatic conditions and a rapid shift of life style toward a more indoor and urbanised pattern are denoted as the probable causes of increased HDM exposure and sensitization. On the contrary, the varying rate of HDM allergy from similar climate and urbanised areas throughout the world suggest the influence of genetic predisposition. At present, in India, avoidance of HDM exposure is recommended as the baseline defence. Allergen immunotherapy (AIT) guidelines are proposed in India to maintain uniformity in the diagnosis techniques and management strategies throughout the country. Considering the genetic susceptibility toward allergic diseases, the concept of 'personalised medicine' is preferred over the 'mass targeted treatment'. From the Indian perspective, the present problem is Dermatophagoides pteronyssinus and D. farinae allergens are not well characterised at the molecular level. As a consequence, India is still reliant on less standardised allergen extracts. The proper identification, purification, and molecular characterization of HDM allergens can combat this problem. In this review, we aimed to portray a complete account of HDM allergy in India with respect to prevalence, probable triggers, diagnosis and therapy. We have attempted to present the current ambiguities along with the likely deciphering that would pave the way to solve HDM allergy-related queries in India.

[Mite sensitization in children followed for respiratory allergy in a tropical African environment in Cotonou, Benin]

INTRODUCTION

In tropical Africa, allergies are not well documented. The objective of this work was to evaluate, by two methods, the sensitization to mites in children followed for respiratory allergy.

METHODS

Skin prick-test and IgE assay by REAST test with 3 mites: Dermatophagoides pteronyssinus (D. pteronyssinus), Dermatophagoides farinae (D. farinae) and Blomia tropicalis (B. tropicalis) were carried out in children from 3 to 15 years followed up for asthma and/or allergic rhinitis. The positive results of the two tests were compared.

RESULTS

Of the 130 (100%) children included, all eligible for the assay, 119 (91.5%) had the prick-test. The mean age and sex ratio (M/F) were 7±1 year, and 1.6. The association of rhinitis and asthma was the most frequent and found in 66 (55.6%). The sensitivity frequencies for the prick-test and assay were respectively 79% versus 36.1% for B. tropicalis, 71.4% versus 33.4% for D. pteronyssinus and 38.7% versus 37.8% for D. farinae. A moderate correlation between mean papule diameter and mean IgE concentration was observed.

CONCLUSION

In African tropical environments, dust mite sensitization in children followed for respiratory allergy is frequent, with the order of frequency being: B. tropicalis, D. pteronyssinus, and D. farinae. The prick-test had better sensitivity than the assay for its evaluation.

Aeroallergen sensitization and associated comorbid diseases of an adult Filipino population with allergic rhinitis

Background

There is a large global variation in sensitization patterns to aeroallergens due to differences in climate, urbanization, and lifestyle. Knowledge of the most common inhalant allergens is important for appropriate prevention and management of allergic rhinitis (AR).

Objective

This study aims to provide data on aeroallergen sensitization patterns and associated comorbid diseases of adult Filipinos with AR.

Methods

Medical records of adult Filipinos seen in an Otolaryngology-Allergy Clinic from January 2011 to 2016 were reviewed. Inclusion criteria used was presence of clinically defined AR and positive skin test to at least one aeroallergen in the test panel. Demographics, comorbid conditions, and results of skin prick test were determined. Standard descriptive statistics were used for analysis.

Results

One hundred ninety-one adult patients were included in this study. Mean age was 38.8 years, and majority lived in an urban area (71.2%). Most patients exhibited polysensitization (97.4%). All exhibited sensitization to indoor and 86.9% to outdoor allergens. The most common indoor allergens were Dermatophagoides pteronyssinus (97.4%), Dermatophagoides farinae, (95.8%), cockroach (80.1%), and molds (72.8%). Bermuda (67%), Johnson grass (58.7%), and Acacia (58.2%) were the most common outdoor allergens. Urticaria (18.8%), dermatitis (16.8%), and asthma (11.5%) were the most common associated comorbid disease. Twelve percent of patients had more than one associated comorbid disease. Asthma + urticaria followed by asthma + dermatitis were the most common co-morbid combinations. One patient had three comorbid diseases: asthma + urticaria + rhinosinusitis.

Conclusion

Compared to earlier studies, aeroallergen sensitization patterns of Filipinos remain unchanged. This study also identifies for the first time, the associated comorbid diseases of AR in this population. Understanding these factors can guide treatment strategies to reduce disease burden.

House Dust Mite Respiratory Allergy: An Overview of Current Therapeutic Strategies

Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence on the efficacy of pharmacotherapy treatment for known HDM-allergic patients is weaker. The standard diagnostic techniques--skin prick test and specific IgE testing--can be confounded by cross-reactivity. However, component-resolved diagnosis using purified and recombinant allergens can improve the accuracy of specific IgE testing, but availability is limited. Treatment options for HDM allergy are limited and include HDM avoidance, which is widely recommended as a strategy, although evidence for its efficacy is variable. Clinical efficacy of pharmacotherapy is well documented; however, symptom relief does not extend beyond the end of treatment. Finally, allergen immunotherapy has a poor but improving evidence base (notably on sublingual tablets) and its benefits last after treatment ends. This review identifies needs for deeper physician knowledge on the extent and impact of HDM allergy in respiratory disease, as well as further development and improved access to molecular allergy diagnosis. Furthermore, there is a need for the development of better-designed clinical trials to explore the utility of allergen-specific approaches, and uptake of data into guidance for physicians on more effective diagnosis and therapy of HDM respiratory allergy in practice.

Risk factors associated with asthma, atopic dermatitis and rhinoconjunctivitis in a rural Senegalese cohort

Background

The World Allergy Organization estimates that 40 % of the world’s population is affected by allergic diseases. The International Study of Asthma and Allergies in Childhood has completed Phase III and it has now become clear that these diseases have increased in developing countries, especially Africa, where prevalence rates were formerly low. Despite an increase in studies in Africa, few sub-Saharan West African countries are represented; the focus has remained on urban populations and little attention has been paid to rural sub-Saharan Africa.

Methods

We performed an allergy survey in a birth cohort of children aged less than 15 years in rural Senegal and implemented an ISAAC questionnaire. We carried out a complete blood count and serological analyses for IgE levels against common allergens and mosquito saliva.

Results

The prevalence rates of asthma, rhinoconjunctivitis (RC) and atopic dermatitis (AD) were 12.8, 12.5 and 12.2 % respectively. Specific IgE (sIgE) levels against mosquito spp. salivary gland antigens were significantly associated with AD; sIgE levels against selected true grasses (Poaceae) were significantly associated with RC. sIgE levels against house dust mite spp. were not associated with asthma, but were significantly correlated with mosquito IgE levels. Such cross-reactivity may blur the association between HDM sIgE and asthma. Consumption of seafood, storing whey cream, using plant fibre bedding and presence of carpet were significantly associated with increased risk of RC. The association of seafood may be the result of histamine intoxication from molluscs prepared by putrefaction. Cat presence and dog contact were associated with increased risk of asthma. Cow contact was associated with increased risk of AD.

Conclusions

Our allergy study in rural West Africa revealed lower prevalence rates than the majority of African urban settings. Although several associated known risk factors were identified, there were associations specific to the region. The identification of probable artefactual dietary phenomena is a challenge for robust diagnosis of allergic disease. The association AD with mosquito saliva, a common allergen in rural settings, warrants specific attention. Further studies in rural Africa are needed to address the aetiology of allergy in a non-urban environment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13223-015-0090-0) contains supplementary material, which is available to authorized users.

Sensitization to airborne allergens among adults and its impact on allergic symptoms: a population survey in northern Vietnam

Background

The knowledge about allergic sensitization and its relationship with clinical symptoms and diseases among adults in South-East Asia is poor. The aim of this study was to investigate the prevalence and pattern of allergic sensitization and the association with asthma and allergic rhinitis in adults in urban and rural Vietnam.

Methods

Among 5,782 responders to a questionnaire survey in northern Vietnam, a random sample was invited to a clinical follow-up and 684 (46%) participated. The methods included a structured interview using a modified GA²LEN study questionnaire on symptoms and possible determinants for diseases. Skin prick test (SPT) with ten common airborne indoor and outdoor allergens, lung function test, and methacholine test was performed among subjects ≤60 years of age.

Results

In total, one third of subjects had a positive SPT reaction to at least one allergen, 36.9% of men and 31.0% of women (n.s.). The most common sensitizer was the storage mite B. tropicalis (men 27.7%; women 18.7%) followed by house dust mite D. pteronyssinus (men 16.5%; women 10.6%), and D. farinae (men 15.3%; women 6.3%), and cockroach (men 16.5%; women 10.2%). Sensitization to all major allergens were significantly more common among men and among subjects ≤45 years compared with women and subjects >45 years, respectively. The prevalence of sensitization to animals, pollen and molds were low. The majority of cockroach-sensitized subjects were also sensitized to mites. Sensitization to any allergen and all major allergens were significantly associated with rhinitis, but not with asthma. However, bronchial hyper-reactivity was significantly associated with increasing number of positive SPTs (p = 0.047).

Conclusions

Among adults in northern Vietnam sensitization to mite and cockroach most common in both rural and urban areas. The dominant sensitizer was the storage mite B. tropicalis, which should be included in future studies and also in clinical practice, owing to its association with clinical symptoms. As in the Western world allergic sensitization was associated with rhinitis and bronchial hyper-reactivity. The lack of association with asthma in South-East Asia needs to be studied further.

Different anti-apoptotic effects of normal and asthmatic serum on normal eosinophil apoptosis depending on house dust mite-specific IgE

We investigated the effect of asthmatic serum on constitutive eosinophil apoptosis in normal subjects. Eosinophil apoptosis in normal subjects was inhibited by asthmatic serum but not normal serum. In a detailed analysis based on the presence of house dust mite (HDM) IgE, HDM IgE-positive (+) asthmatic serum was more effective for eosinophil apoptosis than that of HDM IgE-negative (-) asthmatic serum. HDM IgE+ asthmatic serum inhibited both HDM IgE- and HDM IgE+ normal eosinophil apoptosis, and HDM IgE- asthmatic serum suppressed eosinophil apoptosis of HDM IgE+ normal. HDM IgE- normal serum did not inhibit either HDM IgE- or HDM IgE+ normal eosinophil apoptosis, and HDM IgE+ normal serum inhibited HDM IgE+ normal eosinophil apoptosis. The kind of HDM IgE (Dermatophagoides pteronissinus-specific IgE and Dermatophagoides farinae-specific IgE) was not related to the effect of asthmatic serum on eosinophil apoptosis. Extracts of DP and DF, Der p1, and Der p2, were not effective for eosinophil apoptosis. HDM IgE+ asthmatic serum inhibited cleavage of procaspase 9 and procaspase 3. Asthmatic serum induced Akt and ERK phosphorylation, and ERK activation was suppressed by AKTi. Taken together, asthmatic serum inhibited normal eosinophil apoptosis via PI3K/Akt/ERK cascade. The novel approach taken in this study provided better insight into HDM-associated anti-apoptotic mechanism of eosinophils in patients with asthma.