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PubMed2002

House dust mite barrier bedding for childhood asthma: randomised placebo controlled trial in primary care [ISRCTN63308372].

BACKGROUND: The house dust mite is the most important environmental allergen implicated in the aetiology of childhood asthma in the UK. Dust mite barrier bedding is relatively inexpensive, convenient to use, and of proven effectiveness in reducing mattress house dust mite load, but no studies have evaluated its clinical effectiveness in the control of childhood asthma when dispensed in primary care. We therefore aimed to evaluate the effectiveness of house dust mite barrier bedding in children with asthma treated in primary care. METHODS: Pragmatic, randomised, double-blind, placebo controlled trial conducted in eight family practices in England. Forty-seven children aged 5 to 14 years with confirmed house dust mite sensitive asthma were randomised to receive six months treatment with either house dust mite barrier or placebo bedding. Peak expiratory flow was the main outcome measure of interest; secondary outcome measures included asthma symptom scores and asthma medication usage. RESULTS: No difference was noted in mean monthly peak expiratory flow, asthma symptom score, medication usage or asthma consultations, between children who received active bedding and those who received placebo bedding. CONCLUSIONS: Treating house dust mite sensitive asthmatic children in primary care with house dust mite barrier bedding for six months failed to improve peak expiratory flow. Results strongly suggest that the intervention made no impact upon other clinical features of asthma.

Adolescent↗
PubMed2006

Childhood asthma and indoor allergens in Native Americans in New York.

BACKGROUND: The objective of this study was to assess the correlation between childhood asthma and potential risk factors, especially exposure to indoor allergens, in a Native American population. METHODS: A case-control study of St. Regis Mohawk tribe children ages 2-14 years, 25 diagnosed with asthma and 25 controls was conducted. Exposure was assessed based on a personal interview and measurement of mite and cat allergens (Der p 1, Fel d 1) in indoor dust. RESULTS: A non-significant increased risk of childhood asthma was associated with self-reported family history of asthma, childhood environmental tobacco smoke exposure, and air pollution. There was a significant protective effect of breastfeeding against current asthma in children less than 14 years (5.2 fold lower risk). About 80% of dust mite and 15% of cat allergen samples were above the threshold values for sensitization of 2 and 1 mug/g, respectively. The association between current asthma and exposure to dust mite and cat allergens was positive but not statistically significant. CONCLUSION: This research identified several potential indoor and outdoor risk factors for asthma in Mohawks homes, of which avoidance may reduce or delay the development of asthma in susceptible individuals.

Adolescent↗
PubMed2003

Basophils express a type 2 cytokine profile on exposure to proteases from helminths and house dust mites.

The proteolytic activities frequently associated with sources of allergens and parasite secretions have been suggested as important immunomodulators. We have investigated whether the protease activity of the house dust mite allergen Der p1 and the secreted proteases of the hookworm Necator americanus are able to directly induce type 2 cytokine production by basophils. Der p1 and the secretions of N. americanus induced interleukin (IL)-4, IL-5, and IL-13 but not interferon-gamma mRNA in KU812 basophils. Enzyme-linked immunosorbent assay confirmed that IL-4 and IL-13 were secreted. A nonproteolytic antigen failed to induce cytokine expression, and preincubation of Der p1 or N. americanus secretions with protease inhibitors inhibited cytokine expression. Data were confirmed using basophils purified from human peripheral blood. We speculate that this innate mechanism may contribute to the development of a cytokine milieu that could promote immunoglobulin E synthesis, eosinophil recruitment, and the development of type 2 T cells.

Animals↗
PubMed2005

Acaricidal daphnane diterpenoids from Trigonostemon reidioides (KURZ) CRAIB roots.

A new daphnane diterpenoid, rediocide F (1), was isolated together with three known compounds, rediocides A (2), C (3) and E (4), from the hexane extract of Trigonostemon reidioides roots by bioassay-guided fractionation for acaricidal activity on Dermatophagoides pteronyssinus, Thai common house dust mite. The structure of rediocide F (1) was established as the demethyl analog of rediocide C (3) on the basis of spectral analysis. Compounds 1-4 exhibited potent activity against D. pteronyssinus with respective LC50 values of 2.53, 0.78, 5.59 and 0.92 microg/cm2.

Chromatography, High Pressure Liquid↗
PubMed2002

Determination of antigenic proteins of housedust mites in 90 dogs suffering from atopic dermatitis.

Housedust mites, Dermatophagoides pteronyssinus (D. pteronyssinus) and Dermatophagoides farinae (D. farinae), are the important causative agents of allergic diseases in human and animals. By using 165 dogs suffering from atopic dermatitis (AD), serum levels of immunogloblin E (IgE) antibody against 25 kinds of allergen including housedust mites were determined. Housedust mites were the most frequent allergen against which 90 of the 165 allergic dogs (54.5%) by IMMUNODOT assay. With the further analysis of immunoblotting assay in the 90 dogs sensitized with housedust mites, antigenic proteins of housedust mites recognized by IgE antibodies were with the apparent molecular masses of 15, 76, 90, 98, and 170-kD. Among them, the 15-kD protein that might be identical to Group 2 antigens (Der f2, Der p2) was prominently observed (52/90). This study indicates that about a half of dogs with AD were sensitized to housedust mites, suggesting that Group 2 antigens of housedust mites may be a major allergen in canine AD.

Animals↗
PubMed2005

Effect of pet removal on pet allergic asthma.

BACKGROUND: Allergen avoidance has been recommended in the management of allergic asthma. Very few studies have assessed the effect of pet removal on pet allergic asthma. OBJECTIVE: We examined the effect of pet removal from homes on pulmonary function testing, airway hyperresponsiveness, and medication use. DESIGN: Prospective, nonrandomized, nonblinded observational study. PATIENTS AND METHODS: Subjects included 20 symptomatic patients with newly diagnosed pet allergic asthma who were keeping domestic animals, including hamsters, cats, dogs, and ferrets, and were sensitized to the animals. They were treated with inhaled corticosteroids or other medications according to recommendations by level of severity of the Global Initiative for Asthma. Methacholine inhalation tests were performed regularly before and after starting medication. Clinical features were compared between the patients who gave away their pets according to recommendations by the clinician (removal group) and the patients who refused to give away their pets (keeping group). RESULTS: There were 10 patients in both the removal group and the keeping group. After >or= 1 year of follow-up with or without pet removal, a 5.9-fold increase in the provocative concentration of methacholine causing a 20% fall in FEV(1) was observed in the removal group compared with a 2.3-fold increase in the keeping group (p = 0.04). There were no significant differences in the changes in FEV(1) and peak flow variability. Finally, no patient received inhaled corticosteroids in the removal group, whereas all but one of the patients needed beclomethasone dipropionate (mean dose, 600 mug/d) in the keeping group. CONCLUSION: This study indicates that removal of pets from homes reduces airway responsiveness in patients with pet allergic asthma more than optimal pharmacotherapy alone, thereby enabling a decrease in inhaled corticosteroid doses.

Adult↗
PubMed2006

Increase in concentration of soluble CD86 after segmental allergen challenge in patients with allergic asthma.

STUDY OBJECTIVE: To investigate the effects of segmental allergen challenge on the concentration of soluble CD86 (sCD86) in BAL fluids in patients with allergic asthma. METHODS: BAL fluid and peripheral blood were collected at baseline, 24 h after segmental saline solution or allergen challenge by fiberoptic bronchoscopy and venepuncture, respectively, from 10 patients with allergic asthma. Total and differential cell counts in BAL fluid were performed, and sCD86 levels in both BAL fluid and serum were measured by enzyme-linked immunosorbent assay. RESULTS: In allergic asthmatics, there was no significant increase in BAL sCD86 concentrations after saline solution challenge (median, 2.0 IU/L; 25th to 75th percentiles, 0 to 3.4) compared with baseline control subjects (median, 1.2 IU/L; 25th to 75th percentiles, 0 to 3.6 IU/mL; p = 0.735); however, sCD86 concentrations were significantly elevated after allergen challenge (median, 8.1 IU/L; 25th to 75th percentiles, 4.4 to 17.0 IU/mL; p < 0.001). The concentrations of sCD86 in BAL fluid after allergen challenge exceeded levels that could be accounted for passive transudation from the circulation, based on the magnitude of increases in BAL albumin concentrations. CONCLUSIONS: These data indicate that allergen challenge results in a significant local accumulation of sCD86 within the airways, and that the local release of sCD86 may play a role in allergen-induced inflammatory processes in the asthmatic airways.

Adolescent↗
PubMed2005

Infant sleeping environment and asthma at 7 years: a prospective cohort study.

OBJECTIVES: We investigated the role of infant bedding items, as part of a composite bedding environment, in the development of childhood wheezing. METHODS: This prospective cohort investigation involved 863 children who participated in an infant survey in 1988 and an asthma study in Tasmania, Australia, in 1995. The derived 3 composite infant bedding categories corresponded to increasing numbers of house dust mite (HDM)-rich bedding items used. Outcomes measured included recent and frequent wheezing. RESULTS: Composite infant bedding used was associated with recent wheezing. Effects increased at increasing levels of HDM-rich bedding items used. Effects were further enhanced by home environmental factors of bedroom heating, recent bedroom painting, and absence of bedroom carpeting. When any 2 or more of these environmental factors were present, a strong dose-response relationship was evident. CONCLUSIONS: Our results show that bedding exposures in infancy are prospectively associated with childhood wheezing and that home environmental conditions may modify this association.

Asthma↗
PubMed2004

Sequence tag catalogs of dust mite-expressed genomes: utility in allergen and acarologic studies.

Dust mites are a major source of indoor allergens. They contain a large number of components that react with immunoglobulin (Ig) E in individuals with allergies and are capable of inducing sensitization, and allergic respiratory and cutaneous diseases. With a significant proportion of the population affected in some way by mite allergies, it is essential that we improve our understanding of these organisms so that control strategies could be defined and its allergens better understood. Thus, we have initiated a project using the expressed sequence tagging (EST) strategy to study the major species of dust mites associated with allergic diseases, in particular, the American house dust mite, Dermatophagoides farinae, as well as Blomia tropicalis, the most prevalent mite in domestic tropical dwellings. The work has recently been expanded to include 'storage' mites such as Tyrophagus putrescentiae, Acarus siro, Lepidoglyphus destructor, Glycyphagus domesticus, Suidasia medanensis, and Aleuroglyphus ovatus. More than 50% of the initial 3000 ESTs from the D. farinae and B. tropicalis dust mites showed significant matches to known genes and were categorized into eight functional groups (such as proteins involved in metabolism, gene expression, protein synthesis, cell signaling, etc.). Of specific interest, however, were the homologs to known mite allergens, in addition to a number of sequences bearing significant homology to allergens from non-mite sources previously not known to exist in mites. The availability of these allergen sequences has facilitated their expression and subsequent characterization in our laboratory in terms of their IgE-binding reactivity. The wealth of sequence information, generated via the EST project, has also facilitated the identification of polymorphic forms of allergens, the investigation of differential gene expression under various environmental conditions via DNA microarrays, as well as the analysis of protein level expression profiling via the proteomics approach. Additionally, ESTs have also ameliorated the understanding of the phylogenetic relationships between mites, and enabled the isolation of gene products crucial for life processes so that mite control strategies can be more effectively devised. Taken together, the utilization of the EST strategy has opened up numerous new avenues by which the allergist can engage more effectively in the study of dust mites with the ultimate aim of developing appropriate treatment regimens for mite-induced allergy.

Animals↗
PubMed2006

Molecular cloning of Blomia tropicalis allergens--a major source of dust mite allergens in the tropics and subtropics.

Allergic asthma, rhinitis, rhinoconjunctivitis and atopic dermatitis are the most common allergic disorders that are caused by the house dust mite (HDM). Beside pyroglyphid mites, the clinical importance of non-pyroglyphid mites has also been increasingly recognized in the recent years. Blomia tropicalis is the most important and ubiquitous mite species in tropical and subtropical regions of the world. Well-standardized and characterized allergens are essential for the diagnosis and therapy of house dust mite allergy as well as for the study of the pathophysiology of allergic disease. With the introduction of molecular biology, a number of house dust mite allergens were obtained by cloning the genes encoding the allergens. To date, seven allergens from Blomia tropicalis have been identified and characterized. Among these, Blo t 5, with unknown function, is the major allergen of Blomia tropicalis, with up to 92% of allergic patients sensitized to it. Native Blo t 5 has been purified and shown to consist of multiple isoforms. With advancing knowledge of these specific allergens, it is anticipated that targeted, effective, diagnostic, efficacious and safe therapeutic modalities would be developed.

Allergens↗
PubMed2003

Use of an amplified ELISA technique for detection of a house dust mite allergen (Der f 1) in skin and coat dust samples from dogs.

OBJECTIVE: To use an amplified ELISA technique to document the presence and quantify the concentration of the house dust mite allergen, Der f 1, in skin and coat dust samples collected from dogs. ANIMALS: 29 pet dogs of various breeds. PROCEDURE: Dogs were weighed, and body surface area in square meters was determined. Skin and coat dust samples were obtained by vacuuming dogs. Collected dust was analyzed by use of standard and amplified ELISA techniques. RESULTS: By use of the standard ELISA technique, Der f 1 was detected in skin and coat dust samples from 6 of 29 (21%) dogs. Mean concentration of Der f 1 in the 6 samples with positive assay results was 16.16 ng/mL (range, 5.61 to 31.24 ng/mL). Samples with negative assay results were retested for dust mite allergen by use of an amplified ELISA technique; an additional 14 dogs had positive assay results. Mean concentration of allergen was 0.36 ng/mL (range, 0.19 to 2.20 ng/mL). Combining both techniques, 20 of 29 (69%) dogs had positive assay results for Der f 1. CONCLUSIONS AND CLINICAL RELEVANCE: Results of our study indicate that house dust mite allergens are present on the skin and in the coat of dogs, and this source of allergen may act as a reservoir for allergen exposure in hypersensitive dogs. Use of an amplified ELISA technique to determine environmental concentrations of house dust mite allergens in homes and on dogs will help to identify the relationship between immunologic findings and environmental exposures in dogs with atopic dermatitis.

Allergens↗
PubMed2003

Serum immunoglobulin E against storage mite allergens in dogs with atopic dermatitis.

OBJECTIVE: To determine the prevalence of serum IgE against the storage mites Acarus siro, Blomia tropicalis, and Tyrophagus putrescentiae in a population of dogs with atopic dermatitis. SAMPLE POPULATION: Sera from 84 dogs with atopic dermatitis residing in various regions of the United States and Europe. PROCEDURE: Immunoblotting of sera from atopic dogs was used to identify proteins in mite extracts that bound IgE. RESULTS: 94% of the dogs had serum IgE against proteins in extracts of 1 or more of the storage mite species. Ninety-five, 92, and 89% of the storage mite-sensitive dogs had serum IgE against proteins in extracts of A siro, B tropicalis, and T putrescentiae, respectively. Eighty-two percent had serum IgE against at least 1 protein in all 3 species. Most of the major allergens had molecular weights > 80 kd. A greater percentage of the dog sera had IgE against storage mite proteins, compared with proteins of the house dust mites Dermatophagoides farinae and D pteronyssinus. CONCLUSION AND CLINICAL RELEVANCE: Many dogs with atopic dermatitis have serum IgE against many allergens of storage mites. Most of these allergens, like allergens of dust mites, had molecular weights > 80 kd. Storage mite sensitivity in dogs may be as important, if not more important, than dust mite sensitivity.

Acaridae↗
PubMedDate not supplied

Protozoal forms in house-dust mites and respiratory allergy.

The presence of mites in sputum smears has been described with possible implications through direct action of dust mites inside the lungs and of the possibility of them being a causal factor in asthma. Because of the impact and frequency of allergic respiratory diseases associated with exposure to dust mites, we examine extracts of the intestinal content of dust mites to find a special factor to link the allergic respiratory diseases and the dust mites. We examined 600 slides of household dust with an average of 5 (3-8 mites) mites being observed on each, approximately 3000 mites in all. Among the remains of intestinal contents of the mites, the presence was observed of various protozoal forms with filiform projections. These forms were very similar in morphology to those previously observed by us, under the same conditions of phase contrast, in the sputa of asthmatic patients and the nasal extrusions of patients with allergic rhinosinusitis. The discovery of these protozoal forms may be the nexus necessary to connect these diseases with the arthropods mentioned.

Animals↗
PubMedDate not supplied

Production of interferon gamma in asthmatic patients with small bacille Calmette-Guerin scars: a pilot study.

Some studies suggest a decrease in interferon (IFN) gamma production among atopic individuals, and others refer to low IFN-gamma levels as a characteristic of asthma, regardless of the atopic state. Recent research has indicated a relation between asthma and a tendency toward a bacille Calmette-Guerin (BCG) vaccine scar with a small diameter, suggesting an association of this illness with the low production of IFN-gamma. The aim of this study was to check the hypothesis that asthmatic patients with a small BCG scar present low IFN-gamma production. This work was a quasi-experimental study. The capacity to produce IFN-gamma among 12 asthmatic patients with an average BCG vaccine scar diameter <5 mm was compared with 7 nonasthmatic individuals with scars > or =5 mm using whole blood cells stimulated by purified protein derivative (PPD), phorbol myristate acetatelionomycin (PMA/Iono) and medium (no stimulus). The study also analyzed the relation between IFN-gamma production after PPD stimulation and eosinophil count, total IgE, and dust-mite-specific IgE levels. The asthmatic patients presented a decrease in IFN-gamma production in comparison with a control group after PPD stimulation (p < 0.02). However, the same was not observed when PMA/Iono stimulation was used or when no stimulation was used. Asthmatic patients with small BCG scars showed a decrease in IFN-gamma production, suggesting that there may be an intrinsic characteristic of these patients.

Adolescent↗
PubMedDate not supplied

Reduction of house-dust mite allergen concentrations in carpets by aluminium potassium sulfate dodecahydrate (alum).

Special tools and skilled labor are required to reduce house-dust mite allergens in carpets. The main house-dust mite allergen is Der p 1, a soluble protein found in high abundance in woolen carpets. Current chemical treatment options are either unsafe or ineffective in eradicating Der p 1. Here, we present an effective, safe, and easy application reagent to reduce the allergen levels in carpets. Sixty woolen carpets with Der p 1 concentrations >2 microg/g in fine dust were divided into three homogeneous groups of 20 carpets each, according to their allergen load. We tested alum dissolved in 60 mL of water at doses of 3, 6, and 9 g/m2 against Der p 1 in groups 1, 2, and 3, respectively. The test side of the carpets was sprayed with the reagent. The control side was treated with the 60 mL of tap water. Dust particles were collected from a 1-m2 area on each carpet side 24 hours after treatment and were analyzed for Der p 1 content with a monoclonal ELISA. Alum reduced the Der p 1 concentrations by 48.6 +/- 6.2%, 78.8 +/- 7.2%, and 95.2 +/- 3.0% at 3, 6, and 9 g/m2 in the carpets, respectively. Moreover, there were no complaints registered by the residents against the alum applications. Alum, at 9 g/m2 (in a solution at 15%) in water, can be used for decreasing existing Der p 1 concentrations in woolen carpets.

Air Pollution, Indoor↗
PubMed2005

Clinical effects of Lactobacillus acidophilus strain L-92 on perennial allergic rhinitis: a double-blind, placebo-controlled study.

Studies in animals have suggested that lactic acid bacteria alleviate allergic diseases, however, little information is available on their clinical effect on allergy in humans. Thus, we examined the efficacy of orally administered Lactobacillus acidophilus strain L-92 (L-92) on perennial allergic rhinitis. In a randomized, double-blind, placebo-controlled clinical trial, 49 patients with perennial allergic rhinitis were randomized to receive either 100 mL of heat-treated fermented milk containing L-92 (n = 25) or acidified milk without lactic acid bacteria (placebo; n = 24) for 8 wk. The severity of symptoms was evaluated based on the changes in the scores of clinical symptoms. Oral administration of milk fermented with L-92 resulted in a statistically significant improvement of nasal symptom-medication scores. Ocular symptom-medication scores of patients in the L-92 intervention group tended to improve compared with those in the placebo group. In addition, clear decreases of the scores of swelling and color of the nasal mucosa were observed in the L-92 intervention group at 6 and 8 wk after the start of ingestion of fermented milk. There were no significant differences in serum antihouse dust mite immunoglobulin E levels nor in T helper type 1/T helper type 2 ratio between the 2 groups. These results suggest that oral administration of L-92 can alleviate the symptoms of perennial allergic rhinitis, however, statistically significant changes were not shown in blood parameters.

Animals↗