Effect of rush immunotherapy on airway inflammation and airway hyperresponsiveness after bronchoprovocation with allergen in asthma

Background: Rush immunotherapy (RIT) has been shown to be effective in allergic asthma. Objective: We investigated the mechanisms of RIT on the basis of cytokine production by T-cell lines and airway inflammation and responsiveness. Methods: Subjects were 8 patients with house dust mite–allergic asthma treated with dust mite extract RIT for 6 months and 6 RIT-untreated control patients. IL-5 production by Dermatophagoides farinae –specific T-cell lines, eosinophil percentages, and eosinophil cationic protein (ECP) in induced sputum and airway responsiveness to allergen and histamine were evaluated before and after treatment. Changes in eosinophil percentages and ECP in induced sputum and responsiveness to histamine 24 hours after allergen inhalation were also studied. Results: After 6 months of RIT, percentages of total eosinophils (43.0% ± 6.90% to 16.8% ± 2.48%; P < .01), percentages of EG2⁺ eosinophils (32.6% ± 6.39% to 19.7% ± 4.68%; P < .01) and ECP (362.7 ± 125.3 ng/mL to 26.2 ± 5.15 ng/mL; P < .05) decreased in induced sputum, and IL-5 production by T-cell lines decreased (617 ± 93.2 pg/mL to 200.0 ± 34.1 pg/mL; P < .01). RIT decreased both early- and late-phase bronchoconstriction (early phase: 33.2% ± 3.46% to 25.4% ± 1.42%; P < .03; late phase: 16.2% ± 3.52% to 6.2% ± 1.96%; P < .03) and suppressed increases in the percentages of total (61.8% ± 4.89% to 42.0% ± 4.67%; P < .01) and EG2-positive eosinophils (55.54% ± 7.21% to 36.5% ± 6.43%; P < .01) and ECP (685.6 ± 217.0 ng/mL to 85.4 ± 23.4 ng/mL; P < .05) in induced sputum after allergen inhalation. RIT also decreased airway responsiveness to dust mite (1:303.7 ± 123.7 wt/vol to 1:65.0 ± 13.2 wt/vol; P < .03) and to histamine before (397.1 ± 206.9 μg/mL to 1391.3 ± 283.3 μg/mL; P < .03) and after allergen inhalation (139.2 ± 36.5 μg/mL to 629.1 ± 196.3 μg/mL; P < .03). Conclusion: RIT decreases airway inflammation and airway hyperresponsiveness before and after bronchial provocation with allergen, possibly by inhibiting both allergen-specific T-cell– and mast cell-dependent pathways. RIT is an effective antiinflammatory treatment in allergic asthma. (J Allergy Clin Immunol 1998;102:927-34.)     

Effectiveness of an intervention to reduce house dust mite allergen levels in children's beds

BACKGROUND: In temperate climates, exposure to house dust mite (HDM) allergens is the strongest environmental risk factor for childhood asthma. Environmental modifications to limit exposure have the potential to reduce the prevalence of asthma. The aim of this study was to reduce allergen exposure for children at high risk of developing asthma. METHODS: A total of 616 pregnant women were randomized to HDM intervention and control groups. The control group had no special recommendations whereas the intervention group was given allergen impermeable mattress covers and an acaricidal washing detergent for bedding. Children were visited regularly until 18 months of age to have dust collected from their bed. RESULTS: Der p 1 concentrations in the control group increased from 5.20 microg/g at 1 month to 22.18 microg/g at 18 months but remained low in the intervention group, ranging from 3.27 microg/g at 1 month to 6.12 microg/g at 18 months. CONCLUSIONS: In a high HDM allergen environment, a combined approach using physical barriers and an acaricidal wash, is effective in reducing HDM allergen concentrations in bedding. However, even with these control measures in place, HDM allergen levels remained high by international standards.     

Indoor allergens and longitudinal FEV 1 decline in older adults: The Normative Aging Study

We investigated the relationship between home allergen exposure and decline in FEV₁ in 10 asthmatic and 30 randomly selected, age-matched, nonasthmatic participants in the Normative Aging Study. We defined asthma as subject-reported wheezing apart from colds, with either a physician's diagnosis of asthma or a methacholine PD₂₀ FEV₁ of 8.6 μmol or less. We examined the relationship between the annual decline in FEV ₁ and the concentrations of the cockroach (Blattella germanica) allergens Bla g 1 and Bla g 2, the dust mite (Dermatophagoides pteronyssinus and Dermatophagoides farinae) allergens Der p 1 and Der f 1, and the cat (Felis domesticus) allergen Fel d 1 in house dust specimens. Bla g 1 (–79.8 ml/yr, p = 0.0006) and Bla g 2 (–40.81 ml/yr, p = 0.0004) were significant predictors of decline in FEV₁ after adjustment for age, smoking, and baseline FEV₁. These results were unchanged after elimination of the asthmatic subjects from the analysis. We conclude that cockroach allergen levels in homes is a risk factor for accelerated decline in FEV₁ independent of airway responsiveness. (J Allergy Clin Immunol 1998;101:720–5.)     

Determinants of house dust mite allergen in homes in Wellington, New Zealand

Objectives To measure levels of the major Dermatophagoides pteronyssinus allergen (Der p 1) in homes in Wellington, New Zealand, and to examine factors which affect these levels. Methods As part of a study of risk factors for asthma among 474 8–10-year-old children, standard procedures were used to collect reservoir dust and to measure Der p 1 levels on the living room floor and child's bedroom floor and bedding. Der p 1 levels were analysed both as geometric mean μg/g of fine dust and as μg/m². Questionnaires collected information about factors which might influence these levels, and an average relative humidity in the bed and on the bedroom floor was also measured. Results Similar geometric mean levels of Der p 1 were found at each floor site – 25.5μg/g (95% CI: 22.8–28.5) in the living room and 26.4 μg/g (95% CI: 23.7–29.3) on the child's bedroom floor. The geometric mean level of Der p 1 in the child's bed was 46.6 μg/g (95% CI: 42.3–51.3). After controlling for possible confounders, geometric mean living room and bedroom floor Der p 1 levels were significantly higher in households with older carpet than households with no carpets or newer carpets, and higher in the autumn. Households with three or more children had higher levels of Der p 1 than households with fewer children. Bedding levels were significantly higher in beds with kapok or inner sprung mattresses, or wool underlays and at relative humidities above the mean (51%). Conclusion The very high levels of house dust mite allergen (Der p 1) found in Wellington are likely to be due to a variety of life-style and climatic factors. However, the type and age of floor covering appears to be the single most important factor.     

House dust mite allergen avoidance: a randomized controlled trial of surface chemical treatment and encasement of bedding

To test the effectiveness of a house dust mite (HDM) allergen avoidance strategy we conducted a randomized controlled trial in 35 atopic subjects with asthma, aged 13 to 60 living in Sydney — a high HDM allergen environment. After a 3 month run-in period, subjects were randomized to active allergen avoidance treatment (n= 17) or placebo (n= 18) groups and followed for 6 months. The active treatment involved placing impermeable covers over the mattress, pillows and duvet and spraying the remaining bedding, as well as the carpets and furniture, with a tannic acid/acaricidal spray. Subjects kept a daily record of symptoms and peak expiratory flow rates and had 3 monthly assessments of lung function and airway hyperresponsiveness (AHR). Dust samples were collected from the bed, the bedroom floor and the living room floor at 3 monthly intervals and 2 weeks after the treatment. Mean HDM allergen levels at baseline at these sites were, in the active group, 15.5, 9.6 and 10.2μ/g Der p I/g of fine dust, and, in the placebo group 25.7, 11.8 and 6.3μg/g. Two weeks after the allergen avoidance treatment the HDM allergen level in the beds was reduced to 29% of baseline (95% CI 16.50%, P= 0.038 compared with placebo), but was not significantly different at 3 or 6 months. There was also no significant effect of the allergen avoidance treatment on symptom scores, peak flow variability, lung function or AHR (P > 0.1). We conclude that, in a high HDM allergen environment, simple chemical treatment and encasement of bedding is not sufficient to cause a sustained, beneficial reduction in allergen levels. Effective allergen avoidance requires an active strategy to remove allergen reservoirs and control accumulating allergen within the house.     

Gender differences in indoor allergen exposure and association with current rhinitis

Background Differences between boys and girls in allergic manifestations are well known, and this difference is possibly not attributed to physiological differences alone. Objective We, therefore, investigated whether boys and girls could be exposed to different allergen levels at home and whether indoor allergen levels could be differently associated with rhinitis in boys and girls at 10 years of age. Methods Cat, dog and house dust mite (HDM) allergen levels in mattress dust and interview data regarding current allergic disease were available for 797 10‐year‐old children (360 girls) in The Environment and Childhood Asthma Study in Oslo. Results Girls had higher concentrations of cat and dog allergens in their mattresses compared with boys, also in homes without cats [geometric mean 95% confidence intervals (95% CI): 0.37 (0.31, 0.44) for girls and 0.26 (0.23, 0.30) μg cat allergen/g dust for boys, P=0.002], and without dogs [girls: 0.74 (0.63, 0.86) and boys: 0.55 (0.48, 0.62) μg dog allergen/g dust, P=0.003]. No difference was observed for HDM allergen (Der p 1) levels. Of the 190 (23.8%) children reporting current rhinitis, 144 (75.8%) were sensitized to at least one allergen. The adjusted odds ratio for current rhinitis increased with 1.20 (95% CI: 1.01, 1.42) per 1 μg/g dust increase in Der p 1 for girls (P=0.037), but not for boys (P=0.91). Conclusion Girls had higher levels of cat and dog allergens in mattress dust compared with boys, whereas no difference was observed for Der p 1 allergen. Nevertheless, only increasing levels of Der p 1 and not cat and dog allergens significantly increased the risk of current rhinitis in girls, whereas no significant association was observed for boys. Cite this as: R. J. Bertelsen, C. Instanes, B. Granum, K. C. Lø;drup Carlsen, G. Hetland, K.‐H. Carlsen, P. Mowinckel and M. Løvik, Clinical & Experimental Allergy, 2010 (40) 1388–1397.     

Variability of house-dust-mite allergen levels within carpets

Sensitization and exposure to house-dust-mite allergens is an important cause of asthma. Standardized, reliable, and reproducible methods for measuring exposure are essential for the assessment of the relationship between exposure, sensitization, and asthma. This study investigated the variability of the house-dust-mite allergen Der p 1 concentration in reservoir dust collected within whole carpets in living rooms and bedrooms. The carpets of nine bedrooms and 11 living rooms were sampled. Each room was divided into 1 m² areas measured from wall to wall where the carpet was accessible. Reservoir dust samples were collected by vacuuming each 1 m² area for 2 min. Der p 1 was assayed by a two-site monoclonal-antibody-based immunometric ELISA. Der p 1 was detectable in the carpets of nine bedrooms and six of the 11 living rooms. Within these 15 rooms, there was a wide range of Der p 1 levels. The smallest range of allergen within single room was 0.9 μg Der p 1/g dust (0.2 and 1.1 ng/g; 5.5-fold difference), and the largest was 149.2 μg Der p 1/g dust (0.8 and 150 μg/g; 192-fold difference). The mean range of allergen levels in the living rooms was 11.5 jig Der p 1/g of dust, and the mean coefficient of variation of these rooms was 80.2%. illustrating the huge variation of mite allergen levels within each room. The variation within bedrooms was also large, with a mean coefficient of variation value of 88.7%. The coefficient of variation was significantly lower around soft furnishings or beds (57%) than in the rest the room (89.3%), with the mean difference being 32% (95% CI 27ndash;63%; P=0.04). In conclusion, this study has shown that there is a great variation of Der p 1 levels between areas within a room. No consistent pattern of distribution of mite allergen within a room was found. Der p 1 levels in areas around soft furnishings and beds varied less than the levels in the rest of room.     

Residential characteristics influence Der p 1 levels in homes in Melbourne, Australia

BACKGROUND: Exposure to house dust mite (HDM) allergens is an important risk factor for childhood asthma. Knowledge of environmental determinants of HDM allergen levels is essential before designing rational avoidance measures. AIM: To investigate the effect of domestic characteristics on HDM allergen (Der p 1) levels in Melbourne homes. METHODS: Dust was collected from bed and floor of the bedrooms in 485 houses over a period of one year. Dust was analysed for Der p 1 levels using an enzyme-linked immunosorbent assay. Temperature and relative humidity were measured at the visit. Details of residential characteristics were collected using a questionnaire. Statistically significant predictors of Der p 1 levels (P < 0.05) were identified using multiple linear regression. RESULTS: High levels of Der p 1 were observed in the floors (geometric mean 17.2 microg/g fine dust) as well as in the beds (geometric mean 20.3 microg/g fine dust). Der p 1 levels in the floor dust were significantly lower in winter and spring. They were higher in houses built before 1980 and those with central heating, weather board walls, damp bedrooms or fitted old wool carpets. Der p 1 levels in bed dust were significantly higher in houses built before 1980, with wooden floors built on stumps, with high relative humidity, with visible mould in the room, in beds with an old mattress or in beds without a quilt. CONCLUSIONS: We would encourage construction of homes without carpets, wooden floors on stumps or weather board walls.     

Assay for the major dog allergen, Can f I: Investigation of house dust samples and commercial dog extracts

Monospecific rabbit antibodies were used to develop a sensitive two-site enzyme immunoassay to measure a major dog hair and dander allergen, Can f I. This Can f I assay demonstrated no reaction with 17 heterologous allergen sources, including dog albumin, cat, guinea pig, and horse. Analysis of serial dilutions of purified Can f I and the international standard for dog was parallel. The assay was considered specific for Can f I with a lower limit of detection at 0.03 μg/ml. Total imprecision was from 2% to 6%. Commercial dog extracts for specific immunotherapy contained from 0.7 to 290 μg of Can f I per milliliter. The assay was used to measure Can f I in 136 house dust samples collected from 103 homes across the United States. Concentration of the dog allergen was expressed as micrograms of Can f I per gram of dust. Prevalence of Can f I in the dust samples ranged from <0.3 to 10,000 μg/gm. Serial dilutions of samples containing Can f I were parallel to the standard. The median Can f I value for homes with a dog in residence was 120 μg/gm, and for homes with no dog, 3 μ/gm. With few exceptions, homes with no dog in residence had <10 μg/gm. This Can f I assay will provide useful information for assessing commercial extracts as well as monitoring dog-allergen exposure and allergen-control methods.     

House dust mite and cat allergen in different indoor environments

Allergy to house dust mites (HDM) and domestic pets is a major cause of asthma. People in developed countries spend more than 90% of their time indoors. We have measured levels of HDM allergen Der p I and cat allergen Fel d I in public buildings and public transport. Dust samples were collected by vacuuming a 1 m² area for 2 min from five schools, six hotels, four cinemas, six pubs, three buses, two trains and 12 domestic households without a cat. Der p I and Fel d I were assayed with monoclonal antibodies in a two-site immunometric ELISA. Der p I concentration was significantly higher in the private homes than in comparable sites in public places except for cinema seats (where high values were found) compared with domestic sofas. Der p I >2000 ng/g of fine dust was found in 30% of the upholstered seats, 9% having a concentration > 10000 ng/g. Fel d I levels were significantly higher in the dust from upholstered seats (geometric mean 14±88 μg/g) than in carpeted floors (geometric mean 0±73 μg/g), and in public places than in private homes. Fel d I >8 μg/g was found in 79% of the upholstered seats or furniture sampled in public buildings or public transport. In conclusion, upholstered seats from public buildings and public transport constitute an allergen reservoir for continuous contamination of the indoor environment which could compromise the effects of allergen avoidance employed at home.     

Effects of luminal antigen on intestinal albumin and hyaluronan permeability and ion transport in atopic patients

BACKGROUND: Increased luminal transport of proteins and fluid is part of the inflammatory reaction in inflammatory disease of the bowel and of the airways in allergic diseases and asthma. The objective of this study was to determine intestinal appearance rates of albumin and hyaluronan in vivo in atopic patients allergic to birch, as well as changes in net jejunal transport of monovalent ions and water induced by the antigen. METHODS: Secretion studies were performed with the use of a segmental jejunal perfusion system with a small two-balloon, six-channel tube. The intestinal mucosa was challenged with birch allergen in patients allergic to birch and in matched control subjects (n = 12 in both groups). RESULTS: In patients, but not in control subjects, the luminal antigen induced a net increase in albumin of 2689 ± 567 μg/cm/hr and in hyaluronan of 2609 ± 737 ng/cm/hr (p < 0.01 vs control subjects in both cases). Furthermore, basal net absorption of Cl^- ions, Na⁺ ions, and water was converted to a net secretion after antigen challenge. CONCLUSION: Exposure to antigen normally acting on the respiratory tract induced increased permeability of the gastrointestinal mucosa. This would suggest less organ specificity and more general allergic recognition shared by several immunocompetent tissues in the body, probably mediated by circulating IgE antibodies. (J ALLERGY CLIN IMMUNOL 1996;97:1225-32.)     

Guanine, mite, and cockroach allergens in Costa Rican homes

Previous studies of schoolchildren in Costa Rica have shown an asthma prevalence of 23% and a high level of sensitization, particularly to mite allergens. As a continuation of these studies, some 400 dust samples were collected from various places in Costa Rica, and parts of these were analyzed for specific mite and cockroach allergens, as well as for the number of mites and amount of guanine. Guanine was quantified by a diazo, as well as an HPLC method, which were found to be highly correlated. The concentrations of guanine by the diazo method, Der p 1, Der f 1, and the number of mites were higher in bed dust than in bedroom floor dust, and it was possible to quantify mite allergens and guanine in almost all bed-dust samples. The mean levels were 2–3 times higher than the proposed risk level for elicitation of symptoms in mite-sensitive asthmatics. Bed and bedroom floor dust contained more guanine and mite allergen in humid (>2000 mm rain) than in drier places (P&0.05), but the number of mites in bed and bedroom floor dust was higher in less humid places (P=0.01). The guanine content in bedroom floor dust was higher in areas with a temperate climate than in areas with a warmer climate (P<0.001, Bartlett's chi square [BCS]), as was the number of mites (P<0.01, Kruskal-Wallis [KW], 0.04, BCS) and the Der p 1 concentration (P<0.01, BCS; P=0.02, KW). The Der f 1 concentration in bedroom floor dust was higher in a warmer than in a temperate climate (P<0.001, BCS). More guanine and mites were found in urban than in rural bed dust (P<0.03, KW). Dust samples from the metropolitan area (temperate climate) of Costa Rica contained higher levels of guanine (P<0.01) and Der p 1 (P<0.07) than the coastal areas, but very little Der f 1. In these samples, guanine and Der p 1 allergen were closely related, and 2 μg of the allergen was equivalent to 0.49 mg of guanine. Two-thirds of bed and floor samples collected on cotton filters contained Bla g 2 allergen at mean levels of 1.6 and 2.1 units/g dust, respectively. Cockroach allergen was, however, absent in all bed samples from the metropolitan area, but did occur in very high concentrations in the coastal bed dust samples collected with tighter polyester filters. In conclusion, the concentration of guanine and Der p 1 was very high in the bed dust of Costa Rican homes. Some factors, such as humidity, small houses for large families, and type of bedding, probably favored the heavy mite infestation, which is probably related to the widespread occurrence of bronchial asthma in this country.     

Mattress encasings and mite allergen levels in the Prevention and Incidence of Asthma and Mite Allergy study

BACKGROUND: Reduction of allergen exposure from birth may reduce sensitization and subsequent allergic disease. OBJECTIVE: To measure the influence of mite allergen-impermeable mattress encasings and cotton placebo encasings on the amount of dust and mite allergen in beds. METHODS: A total of 810 children with allergic mothers took part in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) study. Allergen-impermeable and placebo mattress encasings were applied to the childrens' and the parents' beds before birth. Dust samples were taken from the beds of children and their parents before birth and 3 and 12 months after birth. Extracts of dust samples were analysed for mite allergens (Der p 1 and Der f 1). RESULTS: Active mattress encasings were significantly more effective in reducing dust and mite allergen levels than placebo encasings. Mite allergen levels were low in general and the treatment effect was modest. Twelve months after birth, mattresses with active mattress encasings had about half the amount of Der 1 (Der p 1 + Der f 1)/m2, compared to mattresses with placebo encasings, for the child's and the parental mattress. CONCLUSION: This study shows that mite-impermeable mattress encasings have a significant but modest effect on dust and mite allergen levels of mattresses with low initial mite allergen levels, compared to placebo.     

Mite antigen in house dust: relationship with different housing characteristics in the Netherlands

As part of a case-controlled study on the relationship between home dampness and respiratory symptoms of children, the concentration of the major allergen of Dermato-phagoides pteronyssinus (Der p I) in floor dust and mattress dust in 516 dwellings in the Netherlands was measured. A checklist, completed by the investigators, was used to obtain information on home and occupant characteristics, which may have an impact on the Der p I concentration in house dust. The geometric mean mite antigen concentrations were 2370 ng Der p I/g floor dust for the living room, 2201 ng Der p I/g floor dust for the bedroom and 5075 ng Der p I/g mattress dust. In 86% of the houses the maximum concentration was higher than 2000 ng Der p I/g dust, that is regarded as representing a risk for genetically predisposed individuals for the development of specific IgE to house dust mite allergen. In 55% of the houses the maximum concentration exceeded 10000 ng Der p I/g dust, regarded as a risk factor for acute attacks of asthma for mite allergic patients. The Der p I concentrations in dust from carpeted floors were six to 14 times higher than in dust from floors with a smooth floor covering. Higher Der p I concentrations in floor dust were also significantly associated with increasing age of the dwelling and of the floor covering, with an increasing number of occupants, and with the absence of floor insulation. For mattress dust, the age of the mattress, the presence of an outer cavity wall and mechanical ventilation were important factors. Older mattresses had higher levels, and mattress dust from bedrooms with solid brick outer walls had higher levels than that from bedrooms with outer cavity walls. Mattresses in homes with continuous mechanical ventilation had almost twice lower levels than mattresses in homes with natural ventilation. There was a tendency towards higher Der p I concentrations in dust in homes with reported or observed signs of dampness. The Der p I concentrations in dust from carpeted bedroom floors and mattresses were positively associated with the average relative humidity in the bedroom over a period of 3–6 weeks in a subset of the homes where relative humidity was measured. Similar results were obtained using the concentrations of Der p I in ng/m² instead of ng/g dust. The results obtained in this study are of importance for planning and evaluating allergen avoidance measures advised to mite allergic patients.     

House dust mite allergen levels in dust from schools with smooth and carpeted classroom floors

A study was conducted to investigate the levels of house dust mite allergen Der p I in classroom floor dust from 49 schools with smooth (n= 18) or carpeted (n= 31) floors. Schools were located in the city of Rotterdam (n= 29) and in a number of small communities in the Province of Gelderland (n= 20). Data on building characteristics of the schools were obtained. Dust samples were analysed for Der p I content, the major allergen of the house dust mite Dermatophagoides pteronyssinus. The results showed that in schools with carpeted classroom floors, larger amounts of settled dust and higher Der p I levels either expressed as concentrations (in ng/g) or loadings (in ng/m²) were found than in schools with smooth classroom floors. However, the levels of Der p I were considerably lower than in dust collected from floors in homes. Although the Der p I levels were low, effects of several building characteristics on the levels were found. Age of the floor cover, the number of classrooms in the school and the presence of damp spots in the building were related to Der p I concentrations and loadings mainly on carpeted floors. Remarkably, schools in the rural area contained significantly more dust and Der p I than schools in the urban area. We conclude that dust from carpeted classroom floors contains more house dust mite allergen than dust from smooth classroom floors, but much less than dust from floors in homes.     

Immunoreactive β-endorphin in the plasma, pituitary and hypothalamus of young and old male rats

Immunoreactive beta-endorphin (IR-β-ENDO) was measured in the plasma, pituitary, and hypothalamus of young (3–5 mo.) and old (19–23 mo.) male Sprague-Dawley rats, using a specific radioimmunoassay. Plasma IR-β-ENDO in old male rats (3.44±10.54 ng/ml) was more than three times higher than values observed in young male rats (1.00±0.10 ng/ml). Pituitary content and concentration of IR-β-ENDO also were significantly greater in the old (5.85±0.51 μg/gland and 1.17±0.10 μg/mg protein) than in the young (3.53±0.29 μg/gland and 0.78±0.06 μg/mg protein) male rats. The content of IR-β-ENDO in the hypothalamus of old and young rats was nearly the same (43.45±2.47 and 49.88±6.35 ng/hypothalamus, respectively), whereas the concentration of IR-β-ENDO in the hypothalamus of the old male rats (3.89±0.25 ng/mg protein) was approximately 50% lower than that observed in the young male rats (7.80±0.85 ng/mg protein). These changes in plasma, pituitary, and hypothalamic IR-β-ENDO may contribute to the increase in prolactin and decrease in gonadotropins observed in old male rats, since β-ENDO administration is known to produce these effects on prolactin and gonadotropin secretion.     

Effect of dry cleaning on mite allergen levels in blankets

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 1 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.     

Der p I concentrations in mattress surface and floor dust collected from infants' bedrooms

Background Allergen exposure in early childhood is thought to be important for sensitization and subsequent development of asthma. Not much is known, however, about exposure of young children to allergens in the home. Objectives This study was designed to document dust mite allergen exposure in young children, and to determine wheither infants from atopic mothers (=‘high-risk’ infants) are exposed to lower concentrations of house dust mite alkrgen than infants from non-atopic parents (=‘low-risk’ infants). Methods Dust samples were taken in the homes of 104 infants (48 ‘high-risk’ and 56 ‘low-risk’ infants, selected by questionnaire) aged 3–15 months, from floors in different rooms and from the child's mattress surface. Results The majority of the infants were found to be exposed to Der p I concentrations of more than 2000 ng/g in dust collected from the surface of their mattresses. Lower Der p I concentrations were found in mattress surface dust from the beds of infants from atopic mothers than of infants from non-atopic parents. Also, lower Der p I concentrations were found in floor dust from the homes of infants from atopic mothers, Infant beds equipped with new mattresses, new blankets and top plastic sheeting had significantly lower Der p I concentrations than beds equipped with used mattresses and blankets, without top plastic sheeting. Conclusions Young children in the Netherlands are exposed to significant concentrations of Der p I in mattress surface dust. Allergic parents appear to provide their children with environments somewhat less rich in mite allergen than non-allergic parents.