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Objectives: To determine sensitization to house-dust mite (HDM) antigen in under-five children with recurrent wheeze, compare it with nonwheezers, and assess atopic comorbidities in them. Methods: A cross-sectional study was done in the Pediatric department of a teaching hospital in North India, in 190 children aged 1–5 y. Out of these, 127 had recurrent wheeze (RW), and 63 had no wheeze (NW). Sensitivity was done by skin prick test (SPT) for two dust mites antigens: Dermatophagoide farinae and Dermatophagoide pteronyssinus antigens. In addition, atopic comorbidities like atopic dermatitis and allergic rhinitis were assessed. Results: Mean age of the study population was 34.52 ± 20.50 mo. SPT positivity for either of the dust mites was 97 (76.4%) in RW and 13 (20.6%) in NW which was significant (p < 0.001, aOR = 12.27). HDM species sensitization for D. pteronyssinus was 55.1% vs. 15.9% (p < 0.001 aOR = 7.81) and D. farinae was 39.4% vs. 9.5% (p < 0.001, aOR = 5.45) in groups, respectively. Mean wheal size in RW Group was also significantly higher than NW group for D. pteronyssinus (2.39 ± 1.44 vs. 0.52 ± 1.19 mm, median (IQR) 3 (1-3), p < 0.001), D. farinae (1.80 ± 1.39 vs. 0.32 ± 1.00 mm, median (IQR) 2 (0–3), p < 0.001). Allergic rhinitis was present in 55 (43.3%) vs. 7 (11.1%) (p < 0.001), atopic dermatitis in 28 (22%) vs. 2 (3.2%) (p = 0.001) in group 1 and 2, respectively. All children with allergic rhinitis had HDM sensitization in both groups. Conclusion: This study showed early sensitization to HDM in children with recurrent wheeze. Atopic comorbidities were also present in them. [ABSTRACT FROM AUTHOR]

Probiotics are an attractive target for reducing the incidence of allergic disease. Bacillus subtilis is a gut-associated probiotic bacteria that can suppress allergic lung disease; however, it is not clear for how long this protection lasts. We exposed C57Bl/6 mice to B. subtilis via oral gavage and challenged them with intranasal house-dust mite for up to 8 weeks. We found that B. subtilis treatment was able to provide protection from eosinophil infiltration of the airways for 3 weeks. This loss of protection correlated with an increase in the eosinophil chemoattractant CCL24. Additionally, we demonstrate that B. subtilis treatment altered the bacterial composition by increasing the phylum Bacteroidetes and Verrucomicorbiota. The phylum Verrucomicorbiota was reduced in B. subtilis-treated mice at 8 weeks when protection was lost. These results support B. subtilis as a prophylactic for preventing the production of allergic lung disease and highlights that protection can last up to 3 weeks. This work also expands our understanding of how B. subtilis mediates protection and that in addition to modifying the immune system it is also altering the host microbiota.

Abstract House-dust mites (HDM) allergy is the prevailing condition in subjects allergic to inhalants. Clinical studies with HDM extracts—either subcutaneous (SCIT) or sublingual (SLIT) have long been characterized by small sample size, varying allergen doses, and poorly defined endpoints assessing disease severity. In the last decade, well-designed, randomized, controlled studies recruiting thousands of patients have been conducted with newly developed HDM sublingual tablets (SQ®-HDM tablets). This drug is easily dispersible in the oral cavity due to the patented Zydis® technology and its allergen composition is balanced in terms of group I and group II major mite allergen content, reflecting the equal contribution of the two components to HDM sensitization. HDM is the most common allergen associated with asthma. Clinical efficacy of the SQ® HDM SLIT-tablet in HDM allergic asthma has been evaluated in randomized, double-blind, placebo-controlled trials. Both endpoints related to “present” asthma control (inhaled corticosteroid—ICS) as well as endpoints related to “future” asthma control (occurrence of asthma exacerbations) were included in these studies, in agreement with GINA (Global Initiative for Asthma) guidelines. Based on the positive results of these studies, SQ®-HDM SLIT-tablets were approved Europe-wide as registered drug for treating moderate-to-severe allergic rhinitis with or without allergic asthma and not well controlled HDM allergic asthma, associated with allergic rhinitis of any severity. GINA guidelines in 2017 included SLIT-tablet-based immunotherapy as an “add-on” treatment for asthmatic patients sensitized to HDM; indeed, allergen immunotherapy (AIT) is considered to be a complementary treatment option that targets the immunological of allergic diseases, representing the only treatment potentially disease-modifier or, at least, with a long-term efficacy. The availability of a safe, standardized, registered treatment for HDM respiratory allergies is pivotal in the immunotherapy field, pushing it out of a century-long limbo of amatorial interest towards the full dignity deserved by the only casual treatment of respiratory allergies.

House-dust mites (HDM) allergy is the prevailing condition in subjects allergic to inhalants. Clinical studies with HDM extracts—either subcutaneous (SCIT) or sublingual (SLIT) have long been characterized by small sample size, varying allergen doses, and poorly defined endpoints assessing disease severity. In the last decade, well-designed, randomized, controlled studies recruiting thousands of patients have been conducted with newly developed HDM sublingual tablets (SQ®-HDM tablets). This drug is easily dispersible in the oral cavity due to the patented Zydis® technology and its allergen composition is balanced in terms of group I and group II major mite allergen content, reflecting the equal contribution of the two components to HDM sensitization. HDM is the most common allergen associated with asthma. Clinical efficacy of the SQ® HDM SLIT-tablet in HDM allergic asthma has been evaluated in randomized, double-blind, placebo-controlled trials. Both endpoints related to "present" asthma control (inhaled corticosteroid—ICS) as well as endpoints related to "future" asthma control (occurrence of asthma exacerbations) were included in these studies, in agreement with GINA (Global Initiative for Asthma) guidelines. Based on the positive results of these studies, SQ®-HDM SLIT-tablets were approved Europe-wide as registered drug for treating moderate-to-severe allergic rhinitis with or without allergic asthma and not well controlled HDM allergic asthma, associated with allergic rhinitis of any severity. GINA guidelines in 2017 included SLIT-tablet-based immunotherapy as an "add-on" treatment for asthmatic patients sensitized to HDM; indeed, allergen immunotherapy (AIT) is considered to be a complementary treatment option that targets the immunological of allergic diseases, representing the only treatment potentially disease-modifier or, at least, with a long-term efficacy. The availability of a safe, standardized, registered treatment for HDM respiratory allergies is pivotal in the immunotherapy field, pushing it out of a century-long limbo of amatorial interest towards the full dignity deserved by the only casual treatment of respiratory allergies. [ABSTRACT FROM AUTHOR]

Background. Atopic dermatitis (AD) is an early and important step in the propagation of the allergic march, enhancing food and respiratory allergies via epicutaneous sensitisation to allergens. Objectives. To determine the prevalence and patterns of aeroallergen sensitisation, asthma and allergic rhinitis in South African (SA) children with AD. Methods. This was a prospective, observational study in a paediatric university hospital in Cape Town, SA. Children with moderate to severe AD, aged 6 months - 10 years, were recruited randomly and investigated for food sensitisation and allergy. They were assessed for sensitisation to aeroallergens by the immuno solid-phase allergen chip test. House-dust mite DerP and DerF, dust mite Eur m, Timothy grass, Bermuda grass, tree pollen, mould (Alternaria), cat and dog sensitisation patterns were analysed. Symptoms of asthma and allergic rhinitis were elicited using a questionnaire modified from the International Study of Asthma and Allergies in Childhood study questions. Results. One hundred participants (59 black Africans and 41 of mixed ethnicity) were enrolled (median age 42 months). Of the participants, 39% had symptoms of asthma and 53% symptoms of allergic rhinitis; 89% tested positive to at least one aeroallergen, most commonly house-dust mite DerP or DerF (81%), dust mite Eur m (51%), Timothy grass (36%) and cat (35%). Asthma, allergic rhinitis and aeroallergen sensitisation all increased with increasing age, while food allergy decreased with age. Food allergy was not an independent risk factor for respiratory allergies. Children were sensitised to indoor allergens (house-dust mite, pets) from an early age, while pollen allergies increased with age. Conclusions. In this cohort of SA children with moderate to severe AD, comorbidity with respiratory allergies was high. The prevalence of respiratory allergies increased with age while food allergy decreased with age, in keeping with the pattern of the allergic march. Seasonal allergies increased with age, while house-dust mite and pet allergy peaked in younger children, in keeping with early exposure via a defective skin barrier. Early and effective restoration of the skin barrier in AD may be a target for reducing aeroallergen-related diseases.

Background MicroRNAs (miRNAs) may facilitate cell-to-cell communication via extracellular vesicles (EVs). The biological roles of miRNAs in EVs on allergic airway inflammation are unclear. Methods Airway-secreted EVs (AEVs) were isolated from bronchoalveolar lavage fluid (BALF) of control and house-dust mite (HDM) allergen-exposed HDM-sensitized mice. The expression of miRNAs in AEVs or miRNAs and mRNAs in lung tissue was analysed using miRNA microarray. Results The amount of AEV increased 8.9-fold in BALF from HDM-exposed mice compared with that from sham-control mice. HDM exposure resulted in significant changes in the expression of 139 miRNAs in EVs and 175 miRNAs in lung tissues, with 54 miRNAs being common in both samples. Expression changes of these 54 miRNAs between miRNAs in AEVs and lung tissues after HDM exposure were inversely correlated. Computational analysis revealed that 31 genes, including IL-13 and IL-5Ra, are putative targets of the miRNAs up-regulated in AEVs but down-regulated in lung tissues after HDM exposure. The amount of AEV in BALF after HDM exposure was diminished by treatment with the sphingomyelinase inhibitor GW4869. The treatment with GW4869 also decreased Th2 cytokines and eosinophil counts in BALFs and reduced eosinophil accumulation in airway walls and mucosa. Conclusion These results indicate that selective sorting of miRNA including Th2 inhibitory miRNAs into AEVs and increase release to the airway after HDM exposure would be involved in the pathogenesis of allergic airway inflammation. [ABSTRACT FROM AUTHOR]

Backgrounds: House-dust mites are the main cause of allergic rhinitis in Asia, for which immunotherapy (SLIT) is a currently accepted treatment. However, few studies have evaluated the efficiency of SLIT on Asian children with allergic rhinitis for a period longer than one year. The aim of this study was to investigate the efficacy and safety of SLIT for Asian children with allergic rhinitis due to house-dust mites over a 2-year period. Materials and Method: This study included 65 patients who had allergic rhinitis due to Dermatophagoides pteronyssinus and Dermatophagoides farinae. All patients were treated with SLIT (StaloralⓇ). Symptom scores and quality of life were evaluated by using questionnaires over two years. The medication score was assessed monthly by a diary medication card and serologic tests were evaluated before and two years after the start of treatment. Adverse effects and dropout rates were also investigated. Results: All nasal and non-nasal symptoms and quality of life were significantly improved after two years of treatment. Furthermore, the total medication score decreased significantly and the serologic tests showed a significant change two years after the start of SLIT. Although minor adverse effects were reported, no systemic reactions were observed. The dropout rate was 40%. Conclusion: SLIT is an efficient and safe therapeutic tool for a period of two years in Asian children with allergic rhinitis to house-dust mites. [ABSTRACT FROM AUTHOR]

Background: The alarmin interleukin 33 (IL-33) and its receptor ST2 play an important role in mucosal barrier tissues, and seem to be crucial for Th2-cell mediated host defense. Galacto-oligosaccharides (GOS), used in infant formulas, exhibit gut and immune modulatory effects. To enhance our understanding of the immunomodulatory capacity of GOS, this study investigated the impact of dietary GOS intervention on IL-33 and ST2 expression related to intestinal barrier dysfunction and asthma. Methods: B6C3F1 and BALB/c mice were fed a control diet with or without 1% GOS. To simulate intestinal barrier dysfunction, B6C3F1 mice received a gavage with the mycotoxin deoxynivalenol (DON). To mimic asthma-like inflammatory airway responses, BALB/c mice were sensitized on day 0 and challenged on days 7-11 with house-dust mite (HDM) allergen. Samples from the intestines and lungs were collected for IL-33 and ST2 analysis by qRT-PCR, immunoblotting and immunohistochemistry. Results: Dietary GOS counteracted the DON-induced IL-33 mRNA expression and changed the IL-33 distribution pattern in the mouse small intestine. The IL-33 mRNA expression was positively correlated to the intestinal permeability. A strong positive correlation was also observed between IL-33 mRNA expression in the lung and the number of bronchoalveolar fluid cells. Reduced levels of IL-33 protein, altered IL-33 distribution and reduced ST2 mRNA expression were observed in the lungs of HDM-allergic mice after GOS intervention. Conclusions: Dietary GOS mitigated IL-33 at the mucosal surfaces in a murine model for intestinal barrier dysfunction and HDM-induced asthma. This promising effect may open up new avenues to use GOS not only as a prebiotic in infant nutrition, but also as a functional ingredient that targets inflammatory processes and allergies associated with IL-33 expression. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: The relationship between sensitization to Dermatophagoides species and solar irradiation, as reflected by vitamin D, remains elusive. Objective: We investigated the lag time and the cumulative and maximum effects of exposure to solar irradiation on sensitization to house-dust mites. Methods: A time series study design was applied to solar irradiation (MJ/m2) and relative humidity (%) for specific immunoglobulin E (IgE) levels against Dermatophagoides pteronyssinus (n = 20,451) and Dermatophagoides farinae (n = 22,824). We used the distributed lag nonlinear model to assess the difference of log IgE to house-dust mites in relation to climate variables. Results: Compared with specific IgE levels of those exposed to 18 MJ/m2, the maximum increase in sensitization to D. pteronyssinus was observed at a solar irradiation of 10 MJ/m2 at peak 0 week (difference of log IgE 0.368 [95% confidence interval (CI), 0.209-0.529], p < 0.001), and this increase continued for 3 weeks. The IgE level was significantly affected by the relative humidity of the 3rd- to 12th-lag week, and the effect reached its peak at 75% on the 8th week (difference of log IgE 0.394 [95% CI, 0.221-0.566], p < 0.001). The logistic regression analysis showed that solar irradiation was associated with a decreased risk to sensitization to D. pteronyssinus (odds ratio 0.988 per 1 MJ/m2 [95% CI, 0.979-0.997], p < 0.013) on the testing week after controlling for humidity and temperature. Conclusion: This study demonstrated that low solar irradiation immediately increased the risk of sensitization to two house-dust mite species. Further research is warranted to delineate the underlying mechanism of the effect of solar irradiation on aeroallergen sensitization. [ABSTRACT FROM AUTHOR]

Introduction: Specific immunotherapy has shown to be very useful for allergy control in dogs, with a common success rate ranging from 65% to 70%. However, this efficacy could probably be improved and the identification of individual allergomes, with the choice of more adequate molecular allergen pools for specific immunotherapy, being the strategy. Aim: To map Dermatophagoides pteronyssinus (Der p) allergens for mite-sensitized atopic dogs, for better understanding how individual allergograms may influence the response to house-dust mite immunotherapy. Material and methods: To identify the Der p mite allergome for dogs, 20 individuals allergic to dust-mites and sensitized to Der p, were selected. The extract from Der p was submitted to isoelectric focusing (IEF), one-dimensional (1-D) and two-dimensional (2-D) sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Separated proteins were blotted onto polyvinylidene difluoride (PVDF) membranes and immunoblottings were performed with patient sera. Allergen-bound specific IgE was detected. Results: Eleven allergens were identified from isoelectric focusing (IEF), as well as from 1-D SDS PAGE. From 2-D SDS-PAGE, 24 spots were identified. Conclusions: Several similarities were found between dog and human allergograms and no absolute correlation between sensitization and allergy was observed either. As in humans, different individual allergograms do not seem to implicate different clinical patterns, but may influence the response to specific immunotherapy. The molecular epidemiology approach in veterinary allergy management, by the characterization of individual patients' allergoms and by choosing the best molecular allergen pool for each patient could also improve the efficacy of allergy immunotherapy. [ABSTRACT FROM AUTHOR]

Dermatophagoides farinae fecal allergens are a major source of immunogens in home environments; however, as the source of mite fecal allergen is considered spent growth medium extract that can only mimic the pure fecal extract. In this study, we prepared and using proteomic methods analyzed a D. farinae fecal extract for the first time. The preparation approach used D. farinae feces that were produced within 8 weeks of initiating cultivation in minimized growth media. The feces were collected via adhesion to the tissue culture flask surfaces after removing the SGM and mites. This study contains in-depth proteomic mapping of the allergenic isoforms from the D. farinae fecal extract. Despite extensive analysis, MALDI TOF/TOF spectrometry showed that only six proteins/allergens, Der f1, Der f2, Der f3, Der f6, Der f15 and ferritin, originated from D. farinae. No other analyzed proteins were exactly assigned to Dermatophagoides or to similar invertebrate species by sequence similarity. The remaining proteins were assigned mostly to yeasts or cereals (originally dietary proteins); however, many of the proteins were not successfully identified in the current NCBInr. The numerous dietary proteins identified in the feces suggest that these proteins remained highly stable after passing through the gut. Isoforms of the allergens Der f1, Der f3 and Der f15 were identified in more MWs indicating the presence of zymogens and active-enzyme forms. The identified fecal allergens accumulate in the environment during the life of the mite and represent quantitatively greater amounts of mite immunogens than those that were missed in the 2D-E. The results contribute to our understanding of D. farinae digestive physiology with regard to the enzymes/proteins present in the feces. [ABSTRACT FROM AUTHOR]

Background: Two different allergic rhinitis (AR) symptom phenotype classifications exist. Treatment recommendations are based on intermittent-persistent (INT-PER) cataloging, but clinical trials still use the former seasonal AR-perennial AR (SAR-PAR) classification. This study was designed to describe how INT-PER, mild-moderate/severe and SAR-PAR of patients seen by allergists are distributed over the different climate zones in a (sub)tropical country and how these phenotypes relate to allergen sensitization patterns. Methods: Six climate zones throughout Mexico were determined, based on National Geographic Institute (Instituto Nacional de Estadística y Geografía) data. Subsequent AR patients (2-68 years old) underwent a blinded, standardized skin-prick test and filled out a validated questionnaire phenotyping AR. Results: Five hundred twenty-nine subjects participated in this study. In the tropical zone with 87% house-dust mite sensitization, INT (80.9%; p < 0.001) and PAR (91%; p = 0.04) were more frequent than in the subtropics. In the central high-pollen areas, there was less moderate/severe AR (65.5%; p < 0.005). Frequency of comorbid asthma showed a clear north-south gradient, from 25% in the dry north to 59% in the tropics (p < 0.005). No differences exist in AR cataloging among patients with different sensitization patterns, with two minor exceptions (more PER in tree sensitized and more PAR in mold positives; p < 0.05). Conclusion: In a (sub)tropical country the SAR-PAR classification seems of limited value and bears poor relation with the INT-PER classification. INT is more frequent in the tropical zone. Because PER has been shown to relate to AR severity, clinical trials should select patients based on INT-PER combined with the severity cataloging because these make for a better treatment guide than SAR-PAR. [ABSTRACT FROM AUTHOR]

Mattress covers that are impermeable to dust mites may not be effective in treating asthma, according to a study of 1,122 people. Even though the impermeable covers reduced the amount of dust mite allergen in the mattress, it did not improve asthma symptoms or allow patients to use a smaller dose of corticosteroid drugs.

Mattress and pillow covers that are impermeable to dust mites may not be effective in treating hay-fever, according to a study of 232 people. Even though the impermeable covers reduced the amount of dust mite allergen in the mattress, it did not improve the patients' hay-fever symptoms.

Brown Norway (BN) rats develop a robust response to antigens in the lung, characterized by a large increase in allergen-specific immune function and pulmonary eosinophilia. The objective of this study was to investigate alternative models by determining whether other rat strains could be sensitized to house dust mite (HDM) antigen and whether the allergic disease process could be worsened with repeated allergen exposure. In general, BN rats sensitized by either subcutaneous or intratracheal routes exhibited increased pulmonary allergy compared with Sprague-Dawley (SD) and Lewis (L) rats. Multiple intratracheal allergen exposures incrementally increased HDM-specific immune function in BN rats but progressively decreased eosinophil recruitment and markers of lung injury. SD rats had more moderate responses, whereas L rats were relatively unresponsive. Because BN rats developed stronger clinical hallmarks of allergic asthma under various immunization regimes compared with SD and L rats, we conclude that the BN is the most appropriate strain for studying allergic asthma-like responses in rats. Phenotypic differences in response to HDM were associated with differences in the Th1/Th2 cytokine balance and antioxidant capacity. genetic variability; atopy; asthma

Abstract: Lactobacillus plantarum CJLP133 was isolated from Kimchi, a Korean fermented food, and its potential to improve mouse atopic dermatitis after onset was studied. Dermatitis was developed through house dust-mite extract application onto NC/Nga mice, and then CJLP133 feeding was started. CJLP133 suppressed dermatitis-like skin lesions and decreased high serum IgE levels through balancing between IL-4 and IFN-γ in serum. CJLP133 diminished skin thickening, mast cell accumulation into inflamed site, and lymph node enlargement. In lymph node cells, CJLP133 repressed secretion of T cell cytokines such as IFN-γ, IL-4, IL-5, and IL-10. However, CJLP133 decreased ratios of IFN-γ and IL-5 to IL-10 in lymph node cells, while it did not decrease ratios of IL-4 and IL-5 to IFN-γ. Conclusively, CJLP133 exhibited therapeutic potential for atopic dermatitis in mice through orderly increment of type 1 helper T cell activation and regulatory T cell activation. These results suggest that CJLP133 could treat human atopic dermatitis. [Copyright &y& Elsevier]

Introduction: Cutaneous test practice to identify atopy is recommended in persons who suffer persistent asthma. Objective: To estimate the prevalence of allergen sensitization in a group of adult asthma patients; plus, to investigate about the differences that exist between atopic and non-atopic asthmatic persons. Methods: Consecutive asthmatic outpatients were evaluated for the first time in an Allergology Service. They were analyzed through clinical history, physical examination, and allergic cutaneous reactivity to any of 38-allergen panel. IgE serum levels were quantified too. Results: One hundred eighty one asthmatic patients were included. Mean age was 40 years; 75.1% were women; in 59.9%, asthma was accompanied by allergic rhinitis; 81.2% fulfilled the atopy criteria. On average, each patient had 7.2 positive skin tests, corresponding to house-dust mite the highest frequency, followed by cockroach. Subjects age correlated negatively with the amount of positive cutaneous test and IgE serum levels, and positively with severity of asthma. IgE serum level higher than 100UI/ml was identified as a predictive factor for atopic asthma (OR = 3.1, p = 0.03). Conclusions: A substancial amount of asthmatic patients were atopic. The most highly sensitizing allergens were house-dust mite and cockroach. Differences between atopic and non-atopic asthmatics depended on their age and IgE serum levels. [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD) is marked by elevated levels of immunoglobulin E and skin lesions such as oedema and haemorrhage. Kimchi is a Korean fermented food that contains beneficial bacteria for human health. In this study, Lactobacillus plantarum CJLP55, CJLP56, CJLP133 and CJLP136 isolated from Kimchi were investigated for their capacity to inhibit AD. The three strains, CJLP55, CJLP133 and CJLP136, suppressed AD-like skin lesions, high serum IgE levels and epidermal thickening. The three strains diminished the accumulation of eosinophils and mast cells into topical inflammatory sites and the enlargement of axillary lymph nodes, which are responsible for the dorsal dermatitis. CJLP55, CJLP133 and CJLP136 decreased production of type 2 cytokines such as IL-4 and IL-5 in lymph node cell culture. CJLP133 and CJLP136 increased IFN-γ secretion, while CJLP55 enhanced IL-10 production. The three strains isolated from Kimchi suppress house-dust mite-induced dermatitis in NC/Nga mouse, a representative animal model of human AD. These findings suggest that lactobacilli isolated from Kimchi inhibit AD, probably by altering the balance of Th1/Th2 ratio or inducing IL-10 production. [ABSTRACT FROM AUTHOR]

Background: In perennial allergic rhinitis (PAR), the skin-prick test (SPT) is a good diagnostic tool to identify the specific allergens. A nasal provocation test (NPT) is used to identify allergens and to confirm the diagnosis. The aim of this study was to determine the optimal cutoff values of symptom and peak nasal inspiratory flow (PNIF) changes after dust-mite NPT for predicting PAR. We also studied the relationship of the changes of symptoms in NPT and the wheal size of SPT. Methods: One hundred five patients with perennial rhinitis underwent the NPT to Dermatophagoides pteronyssinus and the SPT. The NPT was assessed by changes in symptoms and PNIF. The optimal cutoff values of the symptoms score and PNIF changes after the NPT for predicting the SPT were determined using a receiver operating characteristic (ROC) curve. The relationship of the wheal sizes of SPT and the changes from the NPT were analyzed. Results: Forty-eight patients had a positive SPT to D. pteronyssinus, of whom 33 patients had a positive NPT by increases of the symptom score. Twenty patients had a positive NPT by decreases of PNIF. The area under the ROC curve was 0.85 for symptom score changes and it was 0.612 for PNIF changes. There was a significant correlation between the wheal size of the SPT and symptom changes in the NPT. Conclusion: Nasal provocation is a valuable test to confirm the diagnosis of D. pteronyssinus allergy, especially when the wheal from the SPT is small. The symptom change after the house-dust mite NPT is better than the PNIF change for predicting the PAR. [ABSTRACT FROM AUTHOR]

With a view to producing carpets that could be used to determine the ease of particulate aerosolisation during domestic activity, we measured the cross-sectional distribution of dust-mite allergen, Der p 1, produced using American Society for Testing and Materials method (ASTM F608-89) for embedding house dust in carpets with that produced by several alternative protocols. Allergen concentrations produced at different levels within the pile using the different techniques were also compared with those in carpets from actual houses - in which the majority of allergen is typically found towards the base of the pile. To obtain profiles of allergen, horizontal sections, 2-mm thick, were taken from new carpets after they had been seeded with dust and embedded using one of four following techniques: (1) dragging a fixed roller across the surface of the carpet four times, (2) using the same roller but following it up with 200 revolutions in a hexapod wear simulator, (3) dragging the fixed roller across the carpet surface 30 times (the ASTM method), and (4) 2 minutes under a commercial plate compactor. Fibre from each 2-mm-thick section was collected and the Der p 1 content determined using enzyme linked immunosorbent assay and results expressed as ng Der p 1 per area in each section. Embedding with a fixed roller alone was not found to be particularly effective, resulting in roughly equal amounts of dust being apportioned within each pile layer, irrespective of the number of embedding passes used. In contrast, a distribution biased towards the base of the pile was found after roller-embedding/hexapod wear, although still to a lesser extent than has been observed in used carpets. Plate compaction gave a similar allergen distribution profile to combined roller/hexapod treatment but was considerably easier to perform. Thus, both techniques offer promise for researchers seeking to replicate the cross-sectional distribution of dust mite allergen found in carpets after actual use (and conceivably other particulate pollutants also). [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the relationship between the house- dust mite allergy and prevalence of house-dust mites in dwellings of children who were tested for specific IgE against Dermatophagoides pteronyssinus (D. pteronyssinus) and D. farinae on the suspicion of allergic rhinitis, dermatitis and asthma. All dust specimens collected from children's houses were investigated under a light microscope. House-dust mites were found in 3 1.7% of houses of children with a specific IgE, while the rate was 27.5% in houses of those without a specific IgE. Overall, house dust specimens collected from a total of 92 houses were examined, and mites were found in 27 (29.3%) of them. Both Der p and Der f were found in 38 (92.7%), while mixed allergy (D. pteronyssinus + D. farinae) was found in 3 (7.3%). Der p allergy (100%) was found in all of the allergic children, while no child was found with specific IgE for Der f allergy, except in mixed allergies. [ABSTRACT FROM AUTHOR]

Background: The precise mechanism of specific immunotherapy (SIT), long used for treating allergic diseases, remains undefined. SIT was shown to act by modifying the immune response of T lymphocytes to antigens. We examined the effect of SIT on the expression and use V-alpha, -beta, -gamma and -delta chains of T-cell receptors (TCR) in patients allergic to house-dust mite. Methods: Peripheral venous blood was taken for lymphocyte TCR analysis from 10 house-dust mite (HDM) allergic adults before initiating SIT and 6 months after initiating the treatment. Twelve similarly allergic patients without SIT served as controls. TCR chains were identified by fluorescence-activated cell sorter (FACS) using the following monoclonal antibodies: CD3, CD14, CD8, pan alpha-beta, pan gamma-delta, V-alpha2, V-alpha12.1, V-beta5a, V-beta5b, V-beta5c, V-beta8a, V-beta8b, V-beta3.1, V-beta13, V-beta12, V-beta6.7, V-delta1, V-delta2, V-gamma9, and V-gamma4. Results: Analyzed before and 6 months after SIT initiation, lymphocyte TCR showed significantly increased V-beta5b, V-beta12 and V-alpha12.1 values compared to controls (without significant changes in other markers). Conclusions: SIT caused selective expansion of certain V-beta- and V-alpha-expressing T cells in patients allergic to HDM. Our results support the notion that the effect of SIT in patients with allergic rhinitis may be achieved by modifying the T lymphocyte response through the modulation of TCR usage. [ABSTRACT FROM AUTHOR]

Background: Limpet is a mollusc that is frequently found along the shores of warm seas. Few allergic reactions to limpet have been described, and cross-reactivity with house-dust mites has not been established. Methods: We report five patients with anaphylactic reactions due to limpet ingestion. A limpet extract was prepared and skin prick tests (SPT), radioallergosorbent assays (RAST), sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), and IgE-immunoblotting were performed. In order to evaluate cross-reactivity, an immunoblotting inhibition assay with Dermatophagoides pteronyssinus was also done. Results: All patients were asthmatics sensitized to house-dust mites. In each case, severe bronchospasm was evidenced, and three required mechanical ventilation. Positive SPT with limpet extract was found in the four patients tested. RAST showed specific IgE on each patient's sera. Immunoblotting showed several allergenic fractions with a wide molecular weight range (15–250 kDa). D. pteronyssinus inhibited IgE-binding molecules above 50 kDa in the limpet extract, particularly one molecule of 75 kDa. Conclusions: We describe five patients with IgE-mediated limpet allergy. Severe bronchospasm was the most important symptom. Cross-reactivity with D. pteronyssinus was demonstrated. [ABSTRACT FROM AUTHOR]

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Background: HDM distribution varies between geographic areas and may be affected by housing characteristics. We quantified Der p 1 and Der f 1 and assessed the relationships between their levels and housing characteristics in homes of nonallergic subjects. Methods: Der f 1 and Der p 1 were measured by ELISA in dust samples from living-room floors and mattresses of 44 homes of nonallergic subjects in Pavia. Information about household characteristics was obtained by questionnaire. Results: Der p 1 and Der f 1 concentrations (μg/g dust, median) were 0.34 and 7.8 on mattresses, and 0.15 and 0.83 on living-room floors. Higher Der f 1 levels on mattresses were associated with synthetic pillows (P<0.05), and (only when expressed as μg/m2) with bedding washing temperature of ≤60°C (P<0.05). Der f 1 levels were higher on the living-room floors of homes located on lower (≤first) floors (P<0.05). Good correlations were found between Der p 1 and Der f 1 expressed as μg/g dust and μg/m2 on both mattresses and living-room floors. Conclusions: In homes of nonallergic subjects in northern Italy, Der f 1 exceeded the threshold for sensitization in a high proportion of mattress samples. [ABSTRACT FROM AUTHOR]

Background: The safety and efficacy of sublingual-swallow immunotherapy (SLIT) in rhinitis caused by house-dust mite were evaluated in a double-blind, placebo-controlled study including 75 patients for 24 months. Methods: Patients received either placebo or SLIT with a standardized Dermatophagoides pteronyssinus (D.pt.) – D. farinae (D.f.) 50/50 extract. The mean cumulative dose was 90 000 IR, equivalent to 2.2 mg of Der p 1 and 1.7 mg of Der f I. Symptom and medication scores were assessed throughout the study. Exposure to house-dust mite, skin sensitivity, and serum specific IgE and IgG4 were assessed before starting treatment and after 12 and 24 months. Results: Seventy-two patients (36 active–36 placebo) were eligible for intent-to-treat analysis. Thirty-six patients dropped out of the study. The number of patients who dropped out due to lack of efficacy was eight out of 37 (21.6%) in the active treatment group compared to 15 out of 38 (39.5%) in the placebo group (chi-square=2.81, P=0.09). Total symptom and medication scores decreased significantly after 12 and 24 months (P<0.05) of treatment in both groups, but no significant difference was observed between the active and placebo groups. After 24 months, the number of patients with high levels of indoor allergenic load decreased significantly in both groups compared to baseline data (P=0.01). Specific IgE (D.pt. and D.f.) increased significantly in the active treatment group after 12 and 24 months, while no change was observed in the placebo group. Specific IgG4 levels were not significantly modified in either group. Two patients in each group reported mild adverse effects. No severe adverse effects were reported. Conclusions: We conclude that SLIT in rhinitis caused by house-dust mite was safe, but there was a lack of consistent clinical benefit compared to placebo, probably due to the impact of the allergen avoidance measures that lowered the allergen burden. [ABSTRACT FROM AUTHOR]

A double‐blind, placebo‐controlled study was carried out in 85 patients with a well‐documented history of perennial asthma caused by house‐dust mites. Patients received either placebo or sublingual immunotherapy (SLIT) with a standardized Dermatophagoides pteronyssinus (DP)–D. farinae (DF) 50/50 extract. After a run‐in period, patients received increasing doses up to 300 IR every day for 4 weeks and then three times a week for the following 24 months. The cumulative dose was about 104 000 IR, equivalent to 4.2 mg Der p 1 and 7.3 mg Der f 1. Symptom and medication scores and respiratory function were assessed throughout the trial. Serum specific IgE and IgG4 were determined before SLIT (t0) and after 6 (t1), 11 (t2), 17 (t3), and 25 months (t4) of SLIT. Mite exposure was evaluated at t0, t2, and t4 by semiquantitative guanine determinations. Patients aged 15 years and older were asked to assess their quality of life (QoL) by completing the SF20 (Short Form Health Status Survey) plus two items at t0, t2, and t4. Use of inhaled corticosteroids and β2‐agonists was significantly decreased after 25 months of treatment in both groups (P<0.03). SLIT patients showed significant improvements in respiratory function at t4 (% predicted FEV1 (P=0.01), VC (P=0.002), morning (P=0.01) and evening (P=0.03) PEFR), and reduction in daytime asthma score (P=0.02). In the SLIT group, the post‐treatment PD20 was 1.75 times higher than the baseline value. There was no change in PD20 in the placebo group. Compared to the placebo group, the SLIT group showed a significant increase in specific IgE DP (P=0.05), IgE DF (P=0.02), IgG4 DP (P=0.001), and IgG4 DF (P=0.001) levels after SLIT. QoL scores were similar in both groups at t0 and... [ABSTRACT FROM AUTHOR]

The pathogenetic role of house-dust mites (HDM) in atopic dermatitis (AD) remains controversial, mainly because there is no common agreement on a provocation test that mimics ordinary exposure to HDM. This is related to the lack of knowledge of the mechanism of how HDM allergens enter the body. Theoretically, there are two possible routes: directly through the epidermis, or by inhalation. In ‘atopy patch testing’, a concentrated HDM suspension is tested on the skin under occlusion. This method is frequently used as a model of the epidermal route. The clinical relevance of this method as a provocation test for AD is discussed. As opposed to atopy patch testing, we describe another method, namely, ‘allergen inhalation testing’, as a model of the respiratory route. Twenty patients with AD underwent bronchial provocations with HDM extract in a double-blind, randomized, placebo-controlled study. In nine out of 20 AD patients, bronchial challenge with HDM evoked skin symptoms. All patients with HDM-induced dermatitis had a history of asthma, and as a group they had a higher mean total log-transformed IgE level than the ‘negative skin responders’. Thus, the respiratory route may be relevant in the provocation of AD in a subset of AD patients and may represent an appropriate model of provocation in these patients. Furthermore, the role of HDM in urticaria and allergic rhinitis is discussed. [ABSTRACT FROM AUTHOR]

Background House-dust mites contain components that are allergenic in mite-sensitive patients, and a number of these have been produced in recombinant form. Methods In the present study, we evaluated by skin prick testing the positivity to native Der p 2 and recombinant Der p 2, Der p 5, and Der p 7 allergens of Dermatophagoides pteronyssinus in patients with rhinitis, asthma, or a combination of these diseases, who were positive to whole-mite extract. Results In all patients, the positivity to both native and recombinant Der p 2 was high. In patients with either rhinitis or asthma, the reactivity to Der p 5 and 7 was significantly lower than to Der p 2. However, in patients with combined disease, the positivity to the minor allergens was almost as high as that to Der p 2. Conclusions These results raise the question of whether patients with combined allergic rhinitis and asthma, when compared to those with either of these diseases alone, are predisposed to react to a wider range of mite allergens, or, inversely, whether patients who respond to the minor allergens are more susceptible to suffering the combined disease. [ABSTRACT FROM AUTHOR]

Discusses the environmental and other provocation factors in atopic dermatitis (AD). Information on AD; Hormonal and emotional factors that influence AD pathophysiology; Effect of pollution on AD prognosis; Overview of patch tests for environmental allergens in AD.

The prevalence of sensitization to the storage mites Acarus siro (AS), Tyrophagus putrescentiae (TP), and Lepidoglyphus destructor (LD) was studied in 250 sera of patients with different degrees of sensitization to the house-dust mite Dermatophagoides pteronyssinus (DP) by measuring IgE binding to extracts of the storage mites. Additionally, allergenic crossreactivity between DP and the storage mite species was studied by RAST inhibition with five individual sera (and a pool of these sera) with moderate IgE levels to all three storage mites and to DP. Increased serum IgE to storage mites was found in 46% of the 200 patients sensitized to DP. Increased prevalence rates of IgE titers to storage mites were associated with higher IgE levels to DP In 50 sera without sensitization to DP, only five sera showed increased IgE to one of the storage mites. Extracts of TP almost completely inhibited the IgE binding to AS, and vice versa. DP inhibited IgE binding to all storage mites up to 60%, whereas IgE binding to DP was only minimally inhibited by extracts of storage mites. In conclusion, cosensitization to storage mites is a frequent finding in patients sensitized to DP. Although this is largely the result of cross-reactivity between different mite species, it may nevertheless be of clinical significance in patients exposed to storage mites. [ABSTRACT FROM AUTHOR]

The prevalence of allergic disease is low in Eastern Europe for reasons that are poorly understood. Our study aimed to investigate the levels of exposure to indoor allergens and living conditions among Estonian infants in relation to sensitization. Dust samples were collected during four winter months in 1993/94 from the homes of 197 infants participating in a prospective study of sensitization. Information about living conditions was collected through a home visit and interviewing the mothers when the children were 6 weeks old. Three dust samples were collected from each home: i.e., from the infant's mattress, bedroom floor, and living-room carpet. The levels of allergens were determined by ELISA with monoclonal antibodies. The highest allergen level in a home was regarded as the peak value. The peak geometric mean values (±SD) of Der p 1 and Der f 1 were 0.3 (0.07-1.4) µg/g dust, of Can f 1, 0.86 (0.23-3.12) µg/g dust, and of Fel d 1, 0.1 (0.01-0.9) µg/g dust. In 12 homes (9%), the peak value of house-dust mite (HDM) allergens exceeded 2 µg/g dust, with Der p 1 as the dominating allergen. Multivariate analyses indicated that high levels of HDM allergens were more common in apartments that were on the ground floor or first floor, that were heated with stoves, and/or that had a dampness problem. The mean allergen levels at home were similar in children sensitized to HDM (n = 17. 0.29 vs 0.3 µg/ g dust), dog (n=5, 0.55 vs 1.06 µg/g dust, and cat (n = 18, 0.21 vs 0.09 µg/g dust) and in children who were not sensitized to these allergens. Most of the sensitized children were exposed to relatively low allergen levels at home; i.e., below 1 µg/g dust. This level was exceeded in the homes of 4/17 mite-, 5/18 cat-, and 0/5 dog-sensitized children. The similar levels of the major indoor allergens in Estonia and in Scandinavia indicate that the large differences in atopy prevalence among children and young adults in the two regions are not due to differences in allergen exposure. No allergen threshold level for sensitization was identified. [ABSTRACT FROM AUTHOR]

Recombinant Der p 2, expressed in the baker's yeast Saccharomyces cerevisiae. was used as a tool to determine IgE- and monoclonal antibody (mAb)-binding sites on this allergen. For this purpose, mutant molecules were produced by application of site-directed mutagenesis. The amino-acid residues spanning cys21-cys27 and cys73-cys78 were deleted, thus preventing loop formation through disulfide bonds. Charged residues in three predicted antigenic sites (residues 45-48, 67-1-69. and 88-90) were replaced by alanine residues. IgE- and mAb reactivity to these mutants was compared to that to "wild type" Der p 2. Residues spanning cys73-cys78 were involved in the antigenic binding site for mAb αDpX. Mutations in the areas adjacent to this loop (i.e.. 67+69 and 88-90) had similar effects on this mAb (10- to 20-fold decreases in reactivity were observed), supporting the suggestion that these areas are involved in this antigenic structure. The area of residues 45-48 was shown to be involved in an epitope for mAb 2B12. The reactivity of mAb 7A1 was influenced by substitutions of residues 45-48 as well as 88-90. Deletion of the residues spanning cys21-cys27 resulted in decreased reactivity to three mAbs (10E11, αDpX. and 7A1). From these observations, it may be concluded that binding of different mAbs is influenced by the same mutations and that the binding of single mAbs is influenced by two or more mutations scattered over the allergen molecule. These findings can point in two directions: minor aminoacid changes result in disruption of the overall conformation of the allergen, or distant sites are close together in the three-dimensional structure of the allergen. Decreased IgE reactivity was observed with all mutant molecules, varying between patients. The observed effects ranged from 5- to 1000-fold. Deletion of the amino-acid residues spanning cys21-cys27 and cys73-cys78 had the strongest effect on IgE reactivity, where decreases up to 1000-fold were observed. Such mutants might be useful tools to improve the safety of allergen-specific immunotherapy. [ABSTRACT FROM AUTHOR]

We investigated by enzyme linked immunoassay( ELISA )the IgE response to whole extract of the housedust mite Dermatophagoides pteronyssinus (Dp) and to the native major allergens, Der p 1 and Der p 2, in sera from 18 adult patients (group A) with Dp-allergic asthma before (t0) and 1,2,3 and 4 t1-t4) years after subcutaneous specific immunotherapy (SIT). A qualitative reduction (P=0.05) of the IgE responses to Dp and Der p 2 was observed from t1 to t4, but a highly statistical significant decrease at t3 (P<0.01). With regard to Der p 1 IgE values, the immunotherapy induced a significant decrease (P<0.01) at t3, but not before. In group A, the IgE responses to Der p 1 and Der p 2 were not correlated at t0 (rs = 0.31; P = 0.21) but were correlated at t3 (rs=0.78; P0.001). We also examined sera from 14 adult patients (group B, same SIT schedule as group A) who were without respiratory symptoms at the end of the third year (t3) of Dp SIT. At this time (t3), there were no significant differences in Der p 1 and Der p 2 IgE levels between group A and group B. [ABSTRACT FROM AUTHOR]

Sensitization to the house-dust mite is one of the most important risk factors for asthma, and a dose-response relationship between exposure to house-dust-mite allergens and asthma as well as asthma severity has been shown by several authors. The likelihood of mite-allergen exposure varies according to geographic conditions. To prevent exacerbation and deterioration, of established allergic disease, treatment of symptoms and inflammation should if possible, be combined with allergen avoidance. A broad range of mite-avoidance measures are theoretically possible, and this article reviews possible strategies.

There is a lack of consensus as to the best way to quantify settled house-dust mite Der p 1 allergen from planar and nonplanar surfaces. To investigate the most appropriate measure. of settled house-dust mite Der p 1 allergen, we determined the relationship between Der p 1 allergen content and collected dust weight from planar-surface (mattress) and nonplanar-surface (living-room) samples in 58 homes. There was a direct relationship between Der p 1 content and dust weight br both planar-surface (mattress, n=217) samples (r=0.50, P0.0001) and nonplanar-surface (living-room, n = 48) samples (r=0.61, P0.0001). Correction for the surface area of the planar surface (mattress) vacuum-cleaned resulted in no additional benefit. We conclude that expression of Der p 1 levels per weight of collected dust appears to be the best method for both planar and nonplanar surfaces. [ABSTRACT FROM AUTHOR]

According to the maximum tolerated dose (MTD) achieved, we assessed the changes in clinical and laboratory parameters, induced by specific immunotherapy (SIT), in a group of 43 asthmatic patients sensitized to Dermatophagoides pteronyssinus, over a period of 18 months. A standardized extract (100 Bu/ml; 40 μg/ml of Der p 1; 20 μg/ml of Der p 2) was used. The patients were divided into two groups: the high-dose immunotherapy (HDI) group (MTD ≥= 4 μg Der p I) and the conventional immunotherapy (CI) group (MTD < 4 μg Der p 1). Changes in clinical severity index, medication, and symptom scores; in cutaneous and conjunctival reactivity; and in the levels of specific IgE, IgG, IgG1, and IgG4 to D. pteronyssinus (Der p 1 and Der p 2) were measured (ELISA monoclonal antibodies). Safety was monitored according to the EAACI guidelines. The range of the MTD was 0.8-16 μg of Der p 1. Ninety percent of the patients tolerated a dose of 3.2 μg, but only 18% of the patients reached a maintenance dose of 16 μg. The medians of the accumulated dose were 197 μg of Der p 1 for the HDI group, and 50 μg for the CI group. Conjunctival and cutaneous reactivity was significantly lowered (P< 0.001) after SIT, as were the clinical severity score and medication score in both groups, without significant differences between the groups, except for cutaneous reactivity. Levels of specific IgE decreased significantly (P< 0.01) in both groups, again without significant differences between the groups. The range of the increase in medians of specific IgG, IgG1, and IgG4 was 4.4-120-fold for the HDI group and 3-24-fold for the CI group (P< 0.01). The increase in the levels of Der p 1 and Der p 2 IgG4 were correlated to the changes in cutaneous and conjunctival reactivity (P< 0.01). These results show that a maintenance dose of 3.2 μg Der p 1 (8 BU) can induce pronounced clinical and immunologic changes with an excellent safety profile. [ABSTRACT FROM AUTHOR]

Allergic disease is reflected in a chronic inflammatory response to an allergen. It is thought that local allergen priming underlies this chronicity. To assess the effect of allergen priming on the amplitude and histologic effect of the allergic reaction, four sequential, intracutaneous skin tests were done with 48-h intervals in 13 patients allergic to the house-dust mite Dermatophagoides pteronyssinus (Dpt). Reactions were measured at 15 min, and at 6, 24, and 48 h. Subsequently, epicutaneous tests were done on Dpt-primed spots (n = 5). At 6, 24, and 48 h, reactions increased after priming (P < 0.006), with unaltered early reactions. Epicutaneous reactions to Dpt on primed spots were larger than in epicutaneous controls on similarly primed skin. Local intradermal priming results in greater inflammatory responses at both intra- and epicutaneous challenge. This mechanism may explain the chronicity of allergic reactions at epithelial surfaces. [ABSTRACT FROM AUTHOR]

Although asthmatic children are often sensitized to the house-dust mite (HDM) during early childhood, it is not clear what antigenic components are associated with the early immune response of these children. To investigate this problem, we evaluated IgE, IgG, and IgG4 antibody responses to Dermatophagoides farinae (Df) by immunoblotting among three groups of children: group I aged 0-4 years, group II aged 5-9 years, and group III aged 10-14 years. In the group I subjects, positive IgE-binding reactions to 15- and 25-kDa components were found in 76% and 44% of sera, respectively. Those to other components were generally low in frequency. In contrast, positive IgG-binding reactions to 15- and 25-kDa components were found in 44% and 24% of sera, and those to 30- and 110-kDa components in 48% and 88% of sera, respectively. Positive IgG4 reactions to 15- and 25-kDa components were found in 48% and 24%, respectively, and those to other components were very low. Positive IgE-binding reactions to these components gradually became more frequent with increasing age in groups II and III, while IgG and IgG4 reactivities were not markedly different in these age groups. These results suggest that the 15- and 25-kDa proteins of Df are important antigens associated with the initial IgE response to HDM in early childhood, while the 30- and 110-kDa proteins are associated with IgG and 15-kDa components with IgG4. [ABSTRACT FROM AUTHOR]

In an attempt to prevent or reduce the manifestations of atopic disease, a group of infants considered to be genetically at high risk of atopy was entered in a prenatally randomized, controlled study. A prophylactic group (n = 58) was either breast-fed with their mothers excluding foods regarded as highly antigenic from their diets, or given an extensively hydrolysed formula. In addition, strenuous efforts were made to reduce exposure to the house-dust mite by application of acaricide to the bedroom and living room carpets and upholstered furniture. A control group (n =62) was fed conventionally by breast or on formula, and no specific environmental measures were taken. The results (previously reported) after 1 year showed significantly less total allergy, asthma, and eczema in the prophylactic group. Similar results were obtained at 2 years although the reduction in asthma no longer achieved statistical significance. However, there was significantly, less sensitization, as shown by a battery of skin prick tests (SPTs), to both dietary allergens and aeroallergens in the prophylactic group. All the children have now been reviewed at the age of 4 years, and SPTs to a wide range of dietary allergens and aeroallergens have been performed. The control group continues to show more total allergy (odds ratio [OR] 2.73, 95% confidence interval [CI) 1.21-6.13. P<0.02), definite allergy (allergic symptoms plus positive SPT) (OR 5.6, CI 1.8-17.9, P<0.005), and eczema (OR 3.4, CI 1.2-10.1, P<0.05). More control children have positive SPTs (OR 3.7, CI 1.3-10.0, P<0.02). A dual approach to the prevention of allergic disease, avoiding as far as possible sensitization to food and aeroallergens, significantly reduces the risk of atopic disease. This should be reserved for infants considered at very high risk of atopy, and close medical and dietetic supervision must be available. [ABSTRACT FROM AUTHOR]

Exposure chambers have proven to be valuable tools in studying allergic diseases. The chamber provides a controlled environment and maintains conditions for measuring the amount of allergen inducing symptoms in allergic subjects. The aim of the present study was to develop and test an exposure chamber, The chamber was constructed as an airtight tent, made of transparent polyethylene, easy to adapt to the shape of an existing room, easy to clean, and providing exact allergen-dosage control. Airflow to the interior of the tent was controlled by a variable inlet ventilator fitted with a micropore filter and balanced by a variable high-volume air-sampler on the outlet side. Trace material and allergen were administered as aerosols with a nebulizer connected to the inlet pipe. Samples were obtained from interior surfaces and filters at the outlet. Two different methods were used to test the concept. One method used a colored, neutral trace substance (phenol red indicator) measured photometrically on extracts from filters. Secondly, house-dust mite allergen (Dermatophagoides pteronyssinus) was applied, with samples samples analyzed by an ELISA technique. The results demonstrated the ability of the system to administer and sample allergen with a high degree of reproducibility. A clinical pilot trial proved the capability of the system to initiate symptoms in allergic subjects. [ABSTRACT FROM AUTHOR]

Twenty-three Dermatophagoides pteronyssinus (Dpt)-sensitive asthmatic children aged 7-14 years entered a double-blind, placebo-controlled trial of standardized immunotherapy (IT) (Alpare) while resident at high altitude. Dpt sensitivity was evaluated by skin prick tests at different allergen concentrations at the enrollment and after 6 and 12 months of treatment. Bronchial hyperreactivity was evaluated at the same time points, and on each occasion, histamine challenge and, the following day, Dpt bronchial challenge were performed. All patients, irrespective of active treatment, improved clinically and in lung function with increased PC20 and Dpt-PD20. Alpare-treated patients had a significantly decreased sensitivity on Dpt skin testing (P< 0.009) and felt that their asthma had improved (P< 0.001) compared with placebo-treated subjects, but there was no difference between the treatment groups in lung function or bronchial challenge response. IT neither increased nor decreased bronchial histamine sensitivity. Our results indicate that Dpt IT benefits asthmatic children, but improvement by allergen avoidance at high altitude is even greater. [ABSTRACT FROM AUTHOR]

To study in vivo monitoring variables for bronchial allergen challenges, we investigated the time course of the eosinophil granule proteins, eosinophil cationic protein (ECP) and eosinophil protein X (EPX) after allergen provocation in serum. Thirty-two asthmatic children sensitive to house-dust mites and six healthy young adult controls were challenged by bronchial allergen provocations with Dermatophagoides pteronyssinus and D. farinae. Blood samples were taken at regular intervals up to 24 h. Base-line concentrations of ECP (P < 0.004), EPX (P < 0.002), and eosinophils (P < 0.001) were found to be increased in asthmatic children, as compared with healthy controls. ECP and EPX concentrations showed a uniform pattern with two characteristic features: 1) a rapid increase for both mediators up to 30 min after provocation over base-line values (P < 0.0001 and P < 0.001), followed by a rapid decrease nearly to base-line values in the next 30 min; and 2) a steady increase for ECP and EPX up to 10 h (P < 0.02 and P < 0.01), and even higher levels at 24 h, after challenge (P < 0.002 and P < 0.003). We conclude that although eosinophils are activated in asthmatic children after bronchial allergen challenge, ECP and EPX concentrations are not suitable monitoring variables. Base-line eosinophils seem to predict the occurrence of a late-phase asthmatic reaction alter allergen provocation. [ABSTRACT FROM AUTHOR]

Allergic rhinitis induced by house dust mites (HDMs) is a highly prevalent but often underdiagnosed and undertreated/untreated chronic disease. It often has a negative impact on sleep, work, leisure activities, and health-related quality of life. Allergen immunotherapy is a proven, safe treatment for respiratory allergies. We sought to assess the efficacy and safety of a 300 index of reactivity (IR) sublingual tablet formulation of Dermatophagoides pteronyssinus : Dermatophagoides farinae 1:1 extract in adolescents (aged ≥12) and adults with moderate to severe HDM-induced allergic rhinitis. In a phase III, international, double-blind, placebo-controlled, randomized clinical trial, participants received approximately 12 months of treatment with placebo or the 300 IR tablet. The primary end point was the average total combined score during 4 weeks at the end of the treatment period. A total of 1607 participants were randomized, and 1476 (including 555 [37.6%] with concomitant mild controlled asthma at inclusion) comprised the full analysis set. Over the primary evaluation period, the least squares mean average total combined score in the 300 IR group (3.62) was significantly lower (P <.0001) than in the placebo group (4.35), with a relative least squares mean difference of −16.9% (95% CI, −24.0% to −9.2%). All prespecified secondary end points were consistently improved in the 300 IR group, relative to placebo. The 300 IR tablet was generally well tolerated. Treatment-related adverse events (mainly mild or moderate local reactions) were reported for 51.0% of the patients in the 300 IR group and 14.9% in the placebo group. The 300 IR sublingual HDM tablet is an effective, safe treatment for HDM-induced allergic rhinitis. [ABSTRACT FROM AUTHOR]

A female patient experienced a severe allergic reaction after consumption of vineyard snails. The patient proved to be sensitized to house-dust mite (HDM) and demonstrated a positive skin test and specific IgE to snail (Eobania vermiculata, Lofarma). The snail RAST was > 80% inhibited by HDM, whereas the mite RAST was < 10% inhibited by snail extract. This is possibly another example of food allergy related to primary sensitization by an aeroallergen. [ABSTRACT FROM AUTHOR]

Several epidemiologic studies suggest that in mite-sensitive patients symptoms are dependent upon mite-exposure level. However, in clinical practice, it is not easy to measure major mite allergens. In contrast, assay of specific IgE antibodies can be done routinely. Thus, we wanted to compare, in a group of 40 mite-sensitive patients, the levels of mite-specific IgE (measured by RAST grade 0-6) and the level of mite group I allergen in mattresses (measured in μg/g house dust). The correlation coefficient between both variables was highly significant (P = 0.001). Subjects with a RAST grade of 3 or more had a 77% probability of being exposed to high (i.e., > 10 μg/g dust) mite allergen level. In contrast, subjects with RAST grades 0, 1, or 2 had a 77% probability of not being exposed to such high levels. Thus, measurement of serum mite-specific IgE level could be used in routine prediction of mite exposure. [ABSTRACT FROM AUTHOR]

Summary Infants have a higher risk of developing allergic asthma than adults. However, the underlying mechanism remains unknown. We show here that sensitization of mice with house-dust mites (HDMs) in the presence of low-dose lipopolysaccharide (LPS) prevented T helper 2 (Th2) cell allergic responses in adult, but not infant, mice. Mechanistically, adult CD11b+ migratory dendritic cells (mDCs) upregulated the transcription factor T-bet in response to tumor necrosis factor-α (TNF-α), which was rapidly induced after HDM + LPS sensitization. Consequently, adult CD11b+ mDCs produced interleukin-12 (IL-12), which prevented Th2 cell development by promoting T-bet upregulation in responding T cells. Conversely, infants failed to induce TNF-α after HDM + LPS sensitization. Therefore, CD11b+ mDCs failed to upregulate T-bet and did not secrete IL-12 and Th2 cell responses normally developed in infant mice. Thus, the availability of TNF-α dictates the ability of CD11b+ mDCs to suppress allergic Th2-cell responses upon dose-dependent endotoxin sensitization and is a key mediator governing susceptibility to allergic airway inflammation in infant mice. Graphical Abstract Highlights • Infant mice require high doses of LPS to suppress Th2-driven allergic asthma to HDMs • T-bet+ lung CD11b+ DCs inhibit Th2 cell development after HDM + LPS sensitization • T-bet expression on CD11b+ DCs depends on TNF-α production and TNFR signaling • Infants have an impaired ability to induce TNF-α and T-bet+CD11b+ DCs in response to LPS Children have a higher risk of developing asthma in low-LPS "clean" environments than adults. Bachus et al. demonstrate that infant mice require higher doses of LPS than adult mice to prevent Th2-dependent allergic responses because of the decreased ability to induce LPS-driven TNF-α production and TNFR-mediated CD11b+ dendritic cell activation for Th2 cell suppression. [ABSTRACT FROM AUTHOR]

Many parents may have to do more than buy mattress covers that are impermeable to dust mites to help their children who have asthma or hay-fever. Two studies published in 2003 showed that dust mite-impermeable mattress covers were not effective in reducing the symptoms of asthma or hay-fever. Many houses may contain other allergens from cats and other pets, cockroaches, bacteria, and fungi.

Focuses on the removal of house-dust mites during laundering of bedding. Influence of temperature on the survival of mites; Procedures for the removal of mites.