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Background: Diagnosis and immunotherapy of house-dust mite (HDM) allergy is still based on natural allergen extracts. The aim of this study was to analyze commercially available Dermatophagoides pteronyssinus extracts from different manufacturers regarding allergen composition and content and whether variations may affect their allergenic activity. Methods: Antibodies specific for several D. pteronyssinus allergens (Der p 1, 2, 5, 7, 10 and 21) were used to analyze extracts from 10 different manufacturers by immunoblotting. Sandwich ELISAs were used to quantify Der p 1 and Der p 2 in the extracts. Mite-allergic patients (n = 45) were skin-tested with the extracts and tested for immunoglobulin E (IgE) reactivity to a panel of 10 mite allergens (Der p 1, 2, 4, 5, 7, 8, 10, 14, 20 and 21) by dot blot. Results: Only Der p 1 and Der p 2 were detected in all extracts but their concentrations and ratios showed high variability (Der p 1: 6.0-40.8 μg ml-1; Der p 2: 1.7-45.0 μg ml-1). At least 1 out of 4 allergens (i.e. Der p 5, 7, 10 and 21) was not detected in 8 of the studied extracts. Mite-allergic subjects showed different IgE reactivity profiles to the individual mite allergens, the extracts showed different allergenic activity in skin-prick tests and false-negative results. Conclusions: Commercially available D. pteronyssinus extracts lack important allergens, show great variability regarding allergen composition and content and some gave false-negative diagnostic test results in certain patients. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: The prevalence of allergic rhinitis due to house-dust mites (HDMs) is high and increasing. Treatment guidelines and consensus statements are available, but few data exist on how these are followed in clinical practice in Spain. This study was designed to collect data on diagnosis and treatment of allergic rhinitis due to HDMs and adherence to guidelines in Spanish specialized clinical practice. Methods: In this observational study, patients referred to specialists for a first consultation were collected. Diagnosis of allergic rhinitis due to HDMs was confirmed by skin-prick tests and measurement of specific immunoglobulin E levels. Variables included patient demographics, diagnosis, and treatment. Moreover, investigators answered a questionnaire on their attitudes to allergic rhinitis treatment. Results: Two hundred forty-seven clinicians collected evaluable data from 519 patients (mean age, 24.8 years; SD, 11.9 years; 54% women) with confirmed allergic rhinitis (86.2% with moderate or severe disease and 70.5% with persistent disease; 40% with concomitant asthma) caused by Dermatophagoides. In 85.6% of patients, symptoms had not improved since diagnosis and good disease control was only being achieved in 43.4%. At the study visit, pharmacologic treatment was prescribed in 98.3% and allergen immunotherapy was prescribed in 52.2% of patients. Conclusion: When patients with HDM-induced allergic rhinitis are referred to an allergy specialist in Spain, they have moderate-to-severe persistent disease and are generally not achieving good control with symptomatic treatment. Allergen immunotherapy is prescribed in approximately one-half of patients. In this representative sample of Spanish allergy specialists, the level of adherence to clinical guidelines in these patients is encouraging. [ABSTRACT FROM AUTHOR]

Background: Although the prevalence of allergic rhinitis (AR) is increasing, relatively little is known about patient characteristics in Spain. The aim of this study was to investigate the clinical profile and therapeutic strategies in patients attending Spanish specialists for AR caused by grass pollen or house-dust mites (HDMs). Methods: This was a multicenter cross-sectional epidemiological study of consecutive patients aged ≥5 years with confirmed diagnosis of AR caused by grass pollen or HDMs attending allergy specialists throughout Spain. Demographic and clinical data and information on treatment were collected. Results: Data from 1043 patients were analyzed (524 with grass pollen allergy and 519 with HDM allergy; mean age, 27.1 years). Three-quarters had persistent AR as per the Allergic Rhinitis and Its Impact on Asthma (ARIA) definition, with disease duration of >2 years in 94.3% of those with pollen allergy and 85.5% of those with HDM allergy. Approximately 38% had concurrent asthma. Over one-half of the patients were considered to have gotten worse since the first onset of symptoms. In total, 51.5% did not achieve good disease control with pharmacotherapy and 47.7% were treated with immunotherapy (52.2% of HDM allergic patients and 43.2% of grass pollen-allergic patients). Conclusion: The duration of AR in patients attended for the first time by specialists is long and, in general, the disease does not improve over time and is often not well controlled with pharmacologic interventions. Less than one-half of patients receive allergen-specific immunotherapy that is more often prescribed in HDM allergy. [ABSTRACT FROM AUTHOR]

This study was designed to determine the occurrence, distribution and abundance of house dust mites (HDM) in residential homes in Bandar Abbas (Hormozgan Province), because of numerous complaints of allergies in this oriental city. The study area was divided in five sampling zones based on population density and geographical distribution. In each sampling zone 10 houses were randomly selected. A total of 50 home dust samples were collected using a portable vacuum cleaner for 2 min from 1 m of the surface of mattresses, carpets, sofas and furniture in residential houses. After collection, samples were immediately frozen. Mite species were identified and counted using standard methods and keys. Of the sampled houses 88% (44 houses) were contaminated with at least one HDM species. Three species were identified: Dermatophagoides pteronyssinus (63.1%), D. farinae (32.8%) and D. evansi (4.1%) (Pyroglyphidae). Our findings indicate a relationship between HDM density and moisture and temperature of residential places. The high contamination rate of residential houses (88%) and the favourable environmental conditions for these arthropods stress that they should be considered as important allergic causing agents. [ABSTRACT FROM AUTHOR]

Estimated indoor climate conditions in unheated summer cottages offers house-dust mites unfavorable temperature and feeding conditions while giving them optimum humidity conditions. We aimed to estimate the exposure level of house-dust mites in summer cottages. A total of 37 summer cottages were sampled for house dust and storage mites in three locations and the results compared with samples from 33 patients suspected of house-dust mite allergy and living in ordinary houses. The processed dust samples were investigated by microscopy and exposure levels given as number of mites per 0.1 g dust. The summer cottages were without exception all heavily infested with threefold or higher concentrations of both house dust and storage mites in comparison with ordinary houses. In unheated summer cottages were found tropical high concentrations of house dust and storage mites with a median concentration of house-dust mites in mattress dust of 2000 house-dust mites/g of dust which corresponds to an average of 40 μg allergen/g of mattress dust. As a probable consequence of high indoor air humidity conditions in unheated summer cottages in winter, dust samples contained threefold or higher concentrations of house dust and storage mites. Indoor humidity conditions thus more than compensated for lack of continuous supply of skin scales from human beings and an unfavorable low indoor air temperature. The uniform high mite exposure in summer cottages is likely to imply disease deterioration in patients already allergic to mites. [ABSTRACT FROM AUTHOR]

Mites belong to the most frequent and potent allergen sources. Immunotherapy with mite allergen extracts is frequently performed if allergen avoidance is not possible or successful. However, highly controversial results have been reported for mite-specific immunotherapy. The aim of this study was to develop diagnostic concepts that may contribute to an improved selection of patients for immunotherapy with Der p allergen extracts and that may be used for immunological monitoring of patients undergoing this treatment. The IgE reactivity profiles to Der p extract were determined in a Middle European mite-allergic population by IgE immunoblotting and by using a panel of seven purified natural or recombinant Der p allergens (nDer p 1, nDer p 4, rDer p 2, rDer p 5, rDer p 7, rDer p 8, rDer p 10). Furthermore, we investigated the sensitization and cross-reactivity to house-dust- and storage-mite allergen extracts by CAP FEIA measurements and by IgE competition studies. More than 95% of the patients could be diagnosed with a combination of nDer p 1 and rDer p 2. With the methods used, we could discriminate mite-allergic patients who were mainly sensitized to the major Der p allergens (Der p 1, Der p 2) from patients with a broad sensitization profile, including highly cross-reactive allergens (e.g. Der p 10: tropomyosin) as well as reactivity to storage mites. Diagnostic tests containing the major mite allergens (i.e. Der p 1, Der p 2) and highly cross-reactive mite allergens (e.g. Der p 10) may improve the diagnostic selection of patients for immunotherapy with Der p extracts. These tests may also be used for the immunological monitoring of patients undergoing immunotherapy. [ABSTRACT FROM AUTHOR]

Background: Allergic rhinitis, asthma or the atopic eczema/dermatitis syndrome (AEDS) may independently impair quality of life in patients. However, although many allergic patients may suffer from more than one disorder, the effect of concomitant disease — in particular, the impact of AEDS — is largely unknown. As part of a large multicenter clinical trial on the efficacy of mattress casings in house-dust mite (HDM) allergy, generic quality of life in a mixed population of 224 subjects with rhinitis (n = 198) and/or asthma (n = 111) and/or AEDS (n = 64) was studied. The study aimed to estimate quality of life impairment in these atopic patients and to address the questionissue of whether one atopic disorder goes beyond other existing allergic diseases, thereby causing further impairment to quality of life. Methods: Generic quality of life was assessed by SF-36. Quality of life in the atopic group was compared with a Dutch norm population. Multiple linear regression was used to determine the effects of disease (i.e. the presence of allergic rhinitis, asthma or AEDS) or disease severity, as assessed by visual analog scores (VAS) for asthma, rhinitis, VAS sleeplessness and VAS itching being considered as major symptoms in AEDS on SF-36 domains. Results: Compared to the norm group, atopic patients were impaired in: physical functioning; role physical functioning; general health; vitality; and social functioning. The diagnosis of asthma was negatively associated with the SF-36 subscales for physical functioning (P = 0.02), and general health (P < 0.01). In line with these findings, asthma severity (VAS asthma) was negatively associated with physical functioning (P < 0.01), role physical functioning (P < 0.01), general health (P < 0.0.1), social functioning (P = 0.01), emotional functioning (P = 0.01), and vitality (P = 0.01). VAS sleeplessness had significant negative effect on role physical functioning (P < 0.01), bodily pain (P < 0.01), General health... [ABSTRACT FROM AUTHOR]

In search of potential new indoor allergen sources, all mites in dust from homes of 55 asthmatic children living in three climatic regions in Sweden were counted and identified by light microscope. Antibodies of the IgE class against three house‐dust mites and three storage mites were measured in corresponding serum samples. Mites were found in all but two homes from the northernmost area, where levels also were lower than in the other regions. The highest mite densities were most often found in bedrooms (50%) and living rooms (40%). Mite density was increased in homes with high humidity and was higher in bungalows than in flats. House‐dust mites predominated in the south and storage mites in the east central area, particularly in kitchens and bathrooms. Mite‐density and IgE‐antibody levels against house‐dust mites were significantly associated. The same association applied to storage mites. Other species numbered around 100 mites/g dust in some homes. Microscopy helps to identify potentially important mites. Analysing home dust only for house‐dust mites will underestimate mite exposure. Storage mites may be as relevant to sensitivity as house‐dust mites. As other species occasionally were found in high numbers, their relevance should also be assessed. [ABSTRACT FROM AUTHOR]

Exposure to house-dust-mite allergens is an important cause of allergic reactions in sensitized patients. In community-based studies, sensitization to house-dust mites, as ascertained by a positive skin test or by an increased allergen-specific IgE level in serum, is associated with both diminished lung function and enhanced airway hyperresponsiveness. Sensitization to house-dust mites is an independent risk factor for the development of asthma, especially in areas which favor the growth of house-dust mites. In studies with asthmatic patients, however, the relationship between sensitization to mites and lung function or airway hyperresponsiveness is less clear. The selection of asthmatic individuals (with sensitization to other inhalant allergens) and the use of medication such as inhaled steroids may interfere with the demonstration of a possible association between mite allergy and lung function or airway hyperresponsiveness in asthmatic patients. [ABSTRACT FROM AUTHOR]

Increased exposure to house-dust mites entails a greatly increased frequency of sensitization and increased frequency of mite asthma in the population. The available case-control studies demonstrate large variations worldwide in sensitization and disease risk dependent on the actual level of population exposure. In areas with comparatively tow population exposure to house-dust mites, there is a strong association between exposure and effect, while other areas with a more or less uniformly high population exposure do not demonstrate significant differences between patients and controls because the unexposed groups are too small. As to the existence of a hygienic maximum threshold exposure level, current data all point to a single value of 100 mites/g of dust, corresponding to 2 μg allergen/g of dust. This applies to the risk of sensitization and risk of disease, and when programs of prevention imply exposure below this value, convincing clinical improvement is always observed. Today, the magnitude of the health problem related to population exposure to house-dust mites in many areas is comparable to the effects of active tobacco smoking and traffic accidents. [ABSTRACT FROM AUTHOR]

In cool climates, the humidity circumstances in a home during the summer months arc more important for allergen accumulation than those in the winter months. For the same reasons, a reduction of humidity will have a much greater impact during the summer months. Not only the relative humidity, hut also the removal of the duet mites food by cleaning can be an important factor in determining the ultimate level of mite allergens. These theoretic deductions remain to he experimentally tested. An understanding of the dynamics of mite populations and allergen concentrations in homes and public buildings is still hampered by gaps in our knowledge. These gaps mainly concern the fond availability and food requirements of dust mites and the kinetics of mite allergens. [ABSTRACT FROM AUTHOR]

An understanding of the life cycle of house-dust mites, as well as environmental factors influencing mite populations, can he exploited in mite control. The most important limiting factor for house-dust-mite populations is air humidity. House-dust mites osmoregulate through the cuticle and therefore require a high ambient air humidity to prevent excessive water loss. In addition, the supracoxal glands actively take up ambient water vapour, and the protonymph stage of the life cycle is resistant to desiccation. Larger house-dust-mite populations are found when the absolute indoor air humidity is above 7 g/kg (45% relative humidity at 20°C). Consequently, ventilation by air-conditioning systems is being developed as a means of control. A number of other aspects of the domestic environment are also being manipulated in an integrated approach to render the habitat less suitable for mites. The potential exists for developing models for house-dust-mite populations, environmental characteristics, and the effects of various approaches to control. [ABSTRACT FROM AUTHOR]

Background In coastal Australia, mean house-dust-mite allergen concentration is 20-40 times higher in homes than in public buildings. Allergen concentrations in university colleges, which share some characteristics of both homes and public buildings, are not known. The study aimed to compare bed mite-allergen concentration in colleges with local homes. Methods Mattress dust was collected from three colleges (n = 60 m each) and local homes (n=68) during summer. Der p 1 was measured by ELISA. Information was collected on the floor plan of the colleges, cleaning practices, age of building, and orientation of room. Results Most college mattresses (94%) had Der p 1 concentrations less than the mean of homes in the same climate. The geometric means of Der p 1 m the mattresses of the colleges were as follows: A, 8.9 pg Der p 1/g fine dust (95% CI 6.9,11.5); B, 1.9 (1.5,2.3); and C, 1.5 (1.2,2.0), compared to homes, 22.5 (17.6, 28.7). The percentages of college mattresses with less than 2 μg/ g were 7%, 48%, and 58%, respectively, compared to 4% for homes. Higher Der p 1 concentrations were weakly associated with age of building in college A, and orientation in college B. Der p 1 concentrations were independent of floor level and age of mattress. Conclusions These findings indicate that low allergen concentrations are achievable without extreme hygiene and cleaning measures in a climate which supports mite proliferation in homes. [ABSTRACT FROM AUTHOR]

We have examined the effect of reducing relative humidity (RH), with inbuilt mechanical ventilation and heat-exchange (MVHE) units, on house-dust-mite (HDM) counts and allergen levels, in a pilot study of 10 Wellington dwellings. Recent international prevalence studies in adults and children have confirmed a high prevalence of asthma in New Zealand, Sensitivity to HDM is common among the general population, and HDM is the major allergen associated with asthma. Recent studies of allergen levels have confirmed high concentrations of Der p 1 in the domestic environment. While humidity was significantly reduced in those dwellings fitted with ventilation units, no systematic effect on mites or Der p 1 was observed during the study period. When the reductions in humidity were examined in the context of the time spent below the critical equilibrium humidity (CEH), the intervention led to RH values below the CEH for only 39% of the total of 24-h periods for which measurements were made. Reducing RH by means of MVHE in New Zealand domestic dwellings does not lower humidity sufficiently, or long enough, to have any measurable effect on HDM populations. [ABSTRACT FROM AUTHOR]

The major allergen of Dermatophagoides microceras, Der m 1, as well as the allergens of D. pteronyssinus and D. farinae, Der p 1 and Der f 1, were analyzed in the homes of 111 asthmatic children in three climatic regions in Sweden. The numbers and species of mites were determined by microscopy, and circulating IgE antibodies against mites were measured. Der f 1 was the predominant house-dust-mite (HDM) allergen, Der p 1 the least often found, and Der m 1 represented 31% of the allergen load. However, in the Linköping area, Der m 1 was the major HDM allergen (58%). Mite counts and allergen levels correlated well. Current exposure to HDM allergens at home was associated with the serum IgE antibody response to HDM in the children with no threshold level. Of the children with IgE antibodies against HDM, 67% reacted to all three mites. Mite sensitization rates were marginally increased (7%) by the addition of IgE analysis of D. microceras to the routine analysis of IgE antibodies against D. pteronyssinus and D. farinae. Thus, Der m 1 may be an important HDM allergen and should be considered when HDM exposure data are assessed in areas with a climate like that of Sweden. [ABSTRACT FROM AUTHOR]

This double-blind, placebo-controlled study investigated whether the application of an acaricide (Acarosan®) on mattresses and on textile floor coverings in living rooms and bedrooms can contribute to improvement in lung function and airway hyperresponsiveness in 40 adult asthmatic patients sensitized to house-dust mite. In a second group of 19 patients who refused chemical intervention, the clinical effects of application of allergenimpermeable mattress encasings were studied. In all three treatment groups, Der p 1 levels in mattress dust were statistically significantly decreased after 12 months. However, this decrease was much greater in the group who received mattress encasings (final mean level 430 ng/g) than in groups with acaricide-or placebo-treated mattresses (final mean levels 1730 and 2100 ng/g, respectively). Treatment of textile floors with either Acarosan or placebo chemical caused a statistically significant decrease in the level of the house-dust-mite allergen Der p 1 in floor dust. In the group with mattress encasings, no significant changes of floor dust Der p 1 were found. Airway hyperresponsiveness (as measured by the PC10 histatnine) improved significantly in the mattress cover group after 6 months. The Acarosan group also showed a small but statistically significant improvement after 12 months. [ABSTRACT FROM AUTHOR]

Thirty-one adult patients with asthma caused by house-dust mites (HDM) were included in this placebo-controlled, double-blind study to evaluate the efficacy and safety of specific immunotherapy (SIT) with biologically standardized extracts of HDM. The specific diagnosis was confirmed by skin prick tests, specific IgE, and bronchial provocation tests with HDM allergens. The patients were randomized to receive active treatment with extracts of either Dermatophagoides pteronyssinus (Dpt) or D. farinae (Dfa) (Alutard® SO, ALK, Denmark) or placebo injections. Twenty-three patients completed the study. After 1 year of treatment, we found a clinically important and significant reduction in both asthma medicine consumption (inhaled steroids 38% and beta 2-agonists 46%) and symptom score (57%) in the actively treated group, but not the placebo group. These findings were confirmed by a significant decrease in skin and bronchial sensitivity to HDM in the active group. Additionally, there was a significant difference in the patients' scores for effect in favor of the actively treated group. Total IgE and specific IgE to HDM showed no significant changes before and after treatment for either group. Spirometric lung-function measurements showed a significant increase in forced expiratory volume in 1 s (FEV1) from 85% before to 89% of predicted values after treatment for the actively treated group. Peak-flow measurements at home showed no significant changes during the study. It is concluded that allergen SIT is an effective treatment in adult patients suffering from asthma due to HDM. [ABSTRACT FROM AUTHOR]

The Blomia genus has been described as allergenic in man. The present study aimed to assess the prevalence of B. kulagini sensitization in a large population of allergic subjects without occupational exposure in a subtropical region (Canary Islands, Spain). Secondarily, a new standardized B. kulagini extract was evaluated. The study population comprised 207 patients. RAST for B. kulagini was positive in 76.2% of patients, and 47 of them were selected for the biologic standardization. When the prick test was performed with the nonstandardized extracts, results were positive in 76.6%, whereas when the test was repeated with the standardized extract, sensitivity rose to 95.7%. The conjunctival provocation test was positive in 78.3% of 46 evaluated patients. The bronchial provocation test was positive in 18 sensitized patients and negative in live controls, In conclusion, B. kulagini is an important cause of sensitization among the occupationally unexposed population of the studied area and should be included in allergy diagnostic tests. For reliable prick tests, the use of standardized extracts is mandatory. [ABSTRACT FROM AUTHOR]

The introduction of molecular cloning techniques has led to advances in allergen identification and sequencing, production of recombinant allergens, identification of B-cell and T-cell epitopes, and tertiary structural analysis of allergen molecules. Over 10 groups of mite allergens have been cloned from Dermatophagoides spp., as well as several homologous allergens from Euroglyphus maynei, Lepidoglyphus destructor, and Blomia tropicalis. The availability of these allergens has made it feasible to consider their use for both diagnostic and therapeutic purposes. Several recombinant Dermatophagoides allergens show comparable reactivity on skin testing and in Serologic assays to natural allergens, and cocktails of the recombinant proteins could be used as diagnostic reagents. New technologies have been developed for detection of allergen-specific IgE and for environmental allergen detection using rapid diagnostic tests. Novel approaches to immunotherapy are also being investigated, including T-cell-peptide-based vaccines, allergen variants which lack IgE reactivity, and naked DNA vaccines, The application of allergen biotechnology should lead to improvements in the management of mite-allergic patients with asthma and represents a logical step toward reducing asthma mortality and morbidity. [ABSTRACT FROM AUTHOR]

We investigated the levels of mite allergens (Der p 1 Der f 1, Der 2, and Lep d 1) in dust samples from the homes of 59 patients with asthma, 36 sensitized to house-dust mites (HDM) and 23 to grass pollen (controls), living in Porto. northern Portugal. The relationship between exposure and sensitization to HDM and the influence of housing conditions on mite-allergen levels were also evaluated. Der p 1 (median 9.2 μg/g) and Der 2 (4.6 μg/g) were the main allergens. while Der f 1 and Lep d 1 levels were always <1 μg/g dust and undetectable in 11 % and 47% of samples, respectively. All HDM-sensitized asthmatics were exposed to Der p 1 levels > 2 μg/g and their homes contained significantly higher levels of Der p 1 (median 12.5 vs 6.4 μg/g; P = 0.008) and Der 2 (6.2 vs 3.0 μg/g: P = 0.004) when compared to the control group. A significant correlation was observed between the exposure to Der p 1 and the wheal area at skin testing with the Dermatophagoides pteronyssinus (Dp) extract (P = 0.01) as well as with serum specific IgE levels to Dp (P = 0.03). Patients with higher levels of serum specific IgE (≥ 17.5 HRU/ml) were also more frequently exposed to Der p 1 levels ≥ 10 μg/g (P = 0.002). Old homes, presence of carpets, and signs of dampness were conditions associated with significantly higher levels of mite allergens. In conclusion, we found high levels of Der p 1 and Der 2 particularly in the homes of HDM-sensitized patients and we confirm the relationship between exposure and sensitization to HDM, assessed by both in vivo and in vitro methods. In addition to a favorable outdoor climate, we found in our region housing conditions propitious to mite growth. suggesting that specific geographic characteristics must also he taken into account for the correct planning of mite-avoidance measures. [ABSTRACT FROM AUTHOR]

Mite species adapted to warm, humid climates are commonly found in house dust in the tropics. In Cuba, Dermatophagoides pteronyssinus, D. siboney, and Blomia tropicalis are the most common and abundant mite species in house dust. To investigate the pattern of sensitization of Cuban asthmatic patients to common mite species, we skin-prick-tested (SPT) 148 patients with a clinical history of asthma and possible mite allergy, and determined specific IgE antibodies against mite allergens (D. pteronyssinus, D. farinae, D. siboney, B. tropicalis, Acarus siro, Lepidoglyphus destructor, Tyrophagus putrescentiae, and Glycyphagus domesticus). The prevalence of positive SPT was high to D. siboney (88%), D. pteronyssinus (87%), A. siro (85%), B. tropicalis (85%), and D. farinae (83%). The largest skin reactions were obtained with D. siboney and B. tropicalis extracts. The skin test response to the D. siboney extract correlated to those of D. farinae, D. pteronyssinus, B. tropicalis, and A. siro. The highest IgE levels were found to Dermatophagoides species and B. tropicalis. IgE to D. siboney and B. tropicalis were found in 97% and 96% of the patients, respectively. The prevalence of specific IgE to the other mites studied varied from 46 to 65%. D. siboney and B. tropicalis are important sensitizers among asthmatic patients in Cuba. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate the effects of immunotherapy (IT) with an extract of Dermatophagoides pteronyssinus (Alergo-Merck Depot®) during a 27-month period in patients with allergic asthma to house-dust mites. We included 11 patients (mean age 18 years) treated with a combination of IT and inhaled beclomethasone dipropionate (BDP) in comparison to another 11 (mean age 22 years) treated with BDP alone. We evaluated symptom scores, salbutamol use, peak expiratory flow rates (PEFR), spirometry, and bronchial hyperresponsiveness (BHR) during 18 months of therapy with BDP and in the 9 months after BDP interruption. The two kinds of treatment were efficient and comparable in relation to symptom score, salbutamol use, morning PEFR, FVC, and FEV1, but patients treated with IT and BDP had a faster improvement of BHR and PEFR variability. The interruption of BDP after 18 months of therapy was linked to an impairment of all end points, which were more pronounced in patients previously treated only with BDP. These findings suggest that in selected asthmatic patients allergic to house-dust mites, the association of IT and BDP is more effective than therapy with this inhaled steroid alone due to a faster and more striking improvement during the first months of treatment and to a lower rate of relapse after the interruption of therapy with BDP. [ABSTRACT FROM AUTHOR]

Because the mite-allergen content in homes is highly variable even in the same geographic area, we tried to determine which variables influence mite infestation. We evaluated mite-allergen content in bedding relative to housing conditions and living habits. This cross-sectional study included 108 homes. Housing conditions were assessed by an architect and living habits by a researcher specialized in social and family economics. Group 1 allergen level was measured on the mattress dust with monoclonal antibodies, and relative humidity (RH) was monitored in the bedroom during a 2-week period. Homes with low RH did have low mite-allergen content. In contrast, homes with intermediate RH levels had very variable mite-allergen content. Using analysis of variance and a logistic regression analysis, we were unable to identify any variable predictive of mite-allergen content. Thus, factors other than relative humidity seem to influence mite infestation. Moreover, the absence of association between mite infestation and ventilation rate might be accounted for by the gentle climate in our area with notable outdoor RH. [ABSTRACT FROM AUTHOR]

In Stockholm, Sweden, 17 children with newly diagnosed sensitization to house-dust mites (HDM) and 11 children with previously diagnosed HDM-sensitization were included in a study of HDM-allergen avoidance. Mattress dust was collected on repeated occasions during 18 months and assayed for concentration of major HDM allergens. During the first 12 months, the parents of the intervention group were instructed to intensify cleaning and airing of the child's bedroom. During the last 6 months of the study, the mattresses and pillows of seven children in the intervention group and sibling controls were encased in semipermeable polyurethane covers. The homes exhibited a high absolute indoor humidity throughout the year, and even during the winter the mean levels exceeded 7 g/kg. No mite allergen reduction was seen in the intervention group during the first year. However, among the newly diagnosed HDM-sensitized children, there was a mean reduction of the mattress mite allergen concentration of 83% (P = 0.02). and this was most pronounced in the homes with low humidity. At the end of the mattress encasement period, an average difference of 98% (P < 0.001) was found between the vacuumed amount of mite allergen on top of the covers and that underneath. [ABSTRACT FROM AUTHOR]

To better understand the clinical consequences of exposure to house dust mites (HDM), we investigated the relationship between treatment requirements to control symptoms in mite-allergic asthmatic patients and HDM-allergenic levels in their mattresses. This study included 49 asthmatic subjects recruited from an outpatient clinic. The protocol consisted of a questionnaire about the number of asthma attacks and treatment requirements in the last 3 months. Patients provided a sample of house dust collected from their mattresses by a standardized vacuum cleaning procedure. Mean antigen P1 equivalent defined as the sum of major allergens Der pI and Der fI (Ag P1 Eq) level was 1.34 μg/g dust in patients who had no treatment, 5.4 μg/g dust in patients who took puffs of β2-agonists only when required and 17.8 μg/g dust in patients who required daily long-term treatment. Similar relationships were demonstrated between mean Ag P1 Eq levels and the number of asthma attacks. These data support the clinical role of allergenic exposure in HDM-allergic asthmatics. [ABSTRACT FROM AUTHOR]

To evaluate the effect of preventive measures 46 patients, all allergic to house-dust mites (Dermatophagoides spp.), were randomly allocated to a study and a control group. According to the patients' subjective recordings of symptom score and use of medicine, compared with the control group, the study group had improved. There was, however, no improvement when comparing the objective recordings of morning and evening peak flow and use of medicine, and it is concluded that the preventive measures in this programme are not very effective for patients allergic to house-dust mites. The reduction in indoor humidity in the study group was limited and, as a high indoor humidity is the cause of huge populations of house-dust mites in homes, it is emphasized that future programmes of preventive measures should focus more on damp problems, particularly those related to bad housing construction. [ABSTRACT FROM AUTHOR]

Since one of the greatest reservoirs of allergens is the blanket, we assessed mite allergen levels in dust collected from five blankets by vacuuming before and after dry cleaning with perchlorethylene and compared the results with five control blankets. Assays with monoclonal antibodies showed that group I (Der p I and Der f I) mite allergen levels per g dust were 78% lower after dry cleaning. Group I allergen levels per m² of dry-cleaned blankets were 98% Lower. RAST inhibition showed that total allergen levels decreased 70% after dry cleaning. Mite allergens were not denatured by perchlorethylene. The effect of dry cleaning resulted from physical washing out of dust and allergens. [ABSTRACT FROM AUTHOR]

The article offers information on the genus of house-dust mites (HDM) found on the wall surfaces of damp dwellings. It demonstrates a strong association between HDM and molds on wall surfaces. As stated, most HDM identified belong to the storage mite species. Storage mites genus need higher environmental water activity than Dermatophagoides genus to develop.

Investigates the Der p 1 allergen level, assayed by monoclonal antibody-based enzyme-linked immunosorbent assay, in mattresses belonging to mite-allergenic asthmatics. Correlation of Der p 1 level with mattresses age and housing conditions; Measures to prevent house-dust mite infestations.

Evaluates the prevalence of sensitization to Lepidoglyphus destructor, Glycyphagus domesticus, Acarus siro and Tyrophagus putrescenrtiae in patients with positive skin tests to Dermatophagoides house-dust mites in the Spanish environment. Measurement of specific immunoglobulin E antibodies; Strength of the relationships between the different species of storage mites and house-dust mice.

Examines the presence of mite allergens in feather and synthetic pillows in New Zealand. Increase in the use of non-leather pillows; Levels of major house-dust mite allergen in synthetic and feather pillows; Analysis on the allergens recovered in synthetic pillows.