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The purpose of this study was to evaluate the effects of furniture polish (FP) on the release of cat allergen(Fel d 1)-laden dust from wood surfaces and decay of Fel d 1 in dust over time. About 2 g of sieved (150 μm screen) allergen-laden dust was introduced as an aerosol into an experimental chamber by a Pitt-3 generator and allowed to settle onto two finished wood surfaces pre-treated with either distilled water (DW) or FP. After 24 h, each surface was vacuumed into separate plastic cassettes loaded with 37 mm diameter, 0.4 μm pore, polycarbonate filters. The recovered dust was weighed, extracted in phosphate-buffered saline, and assayed for Fel d 1 content using a two-site monoclonal antibody ELISA. After vacuuming, the remaining dust on the wood surfaces was wiped up with a water-moistened swab. The dusts were extracted from the swabs and assayed by ELISA for Fel d 1. More Fel d 1 was recovered by vacuuming from DW-pre-treated surfaces than from FP pre-treated surfaces (100% vs. 69 ± 66%). On the contrary, more residual Fel d 1 (>99.9%) on the vacuumed surfaces was recovered from FP than from DW pre-treated surfaces by wet swabs. The concentration of Fel d 1 in dust did not change significantly at room temperature over 80 days. In conclusion, FP on wood surfaces makes dust stick to the surface, which likely reduces the release of allergen-laden dust from the wood surface. Re-aerosolization of cat allergen-laden dusts from wood surfaces (e.g. wood floor or furniture) significantly increases the concentration of airborne cat allergens. Our study indicates that exposure to airborne cat allergens might be reduced by surface treatment with commercially available FP because cat allergen-laden dusts stuck more tightly to the wood surface treated with FP. [ABSTRACT FROM AUTHOR]

We have previously described both modification of allergen immunotherapy using peptide fragments, and reduced regulation of allergen stimulated T cells by CD4+ CD25+ T cells from allergic donors when compared with nonallergic controls. It has been suggested that allergen immunotherapy induces regulatory T cell activity: we hypothesized that allergen peptide immunotherapy might increase suppressive activity of CD4+ CD25+ T cells.To examine cat allergen-stimulated CD4 T cell responses and their suppression by CD4+ CD25+ T cells before and after cat allergen peptide immunotherapy in a double-blind placebo-controlled study.Peripheral blood was obtained and stored before and after peptide immunotherapy or placebo treatment. CD4+ and CD4+ CD25+ were then isolated by immunomagnetic beads and cultured with allergenin vitro.Comparing cells from blood taken before with that after peptide immunotherapy there was a significant reduction in both proliferation and IL-13 production by allergen-stimulated CD4+ T cells, whereas no change was seen after placebo. CD4+ CD25+ T cells suppressed both proliferation and IL-13 production by CD4+ CD25− T cells before and after therapy but peptide therapy was not associated with any change in suppressive activity of these cells.Allergen peptide immunotherapy alters T cell response to allergen through mechanisms other than changes in CD4+ CD25+ T cell suppression. [ABSTRACT FROM AUTHOR]

Background: Some schools in Sweden offer allergen avoidance classrooms for allergic children with severe asthma. However, the measures commonly used to achieve a reduction in allergen levels have not been properly evaluated. The aim of the present prospective study was to study whether the levels of airborne cat allergen are altered after introducing feasible intervention measures in classrooms, without interfering with peoples' freedom of choice regarding pet ownership. Methods: Twenty-five classes, including five established allergy prevention classrooms participated in the study during a school year. After one term, six classes underwent a number of intervention measures recommended by the Swedish National Institute of Public Health. Curtains, upholstery and plants were removed, bookshelves were replaced with cupboards and regular cleaning was increased. Airborne dust was collected weekly (32 weeks) using duplicate Petri dishes ( n = 1574) and on six occasions using two personal air samplers in each class ( n = 264). Results: Airborne cat allergen levels were showing a similar variability throughout the whole study in all classes. Despite extensive measures in order to reduce allergen exposure, cat allergen levels were unaltered in the six classes after intervention. Allergen levels were not significantly lower in the established allergy prevention classes, compared with the other classes. Cat allergen levels differed, however, significantly between classes with few and many cat owners ( P < 0.05). Conclusions: We conclude that the recommended allergen avoidance measures used in this study did not reduce airborne cat allergen. It seems plausible that measures that fail to reduce allergen levels also fail to influence health status in allergic children but this remains to be shown. [ABSTRACT FROM AUTHOR]

Vacuum cleaners with a central exhaust may lead to lower airborne dust and allergen concentrations compared with regular vacuum cleaners. In 12 houses, equipped with a central vacuum cleaning system, a standardized vacuum cleaning protocol was performed comparing airborne dust and allergen concentrations between the central system and a regular cleaner. Airborne dust concentrations during (104 vs. 95 μg/m3) and after vacuum cleaning (38 vs. 36 μg/m3) were not significantly different. In houses with a cat, Fel d 1 concentrations were also not significantly different either during (6.12 vs.5.91 ng/m3) and after (0.64 vs. 0.91 ng/m3) use of the vacuum cleaners. Airborne dust and Fel d 1 concentrations increased considerably during use of both vacuum cleaners. Compared with central vacuum cleaning systems, conventional modern vacuum cleaners do not cause higher airborne dust or cat allergen concentrations during and after use. This study shows that the amount of dust or cat allergen in the air during and after vacuum cleaning is similar when comparing a central vacuum cleaner with a regular vacuum cleaner. Therefore, allergen avoidance advice given to reduce exposure of allergic asthmatic patients to allergens, does not necessarily have to include switching to a central vacuum cleaner. [ABSTRACT FROM AUTHOR]

Studies investigating the effect of exposure to indoor allergens and endotoxin on human respiratory health usually take dust samples only at one single point of time and consider them to be representative for the indoor biocontaminant burden during a time period of several years. This singly measured biocontaminant concentration is related to adverse respiratory outcomes such as asthma, wheeze or others. We analysed two repeated measurements of mite and cat allergens in mattress and living room floor dust as well as endotoxin concentrations in living room floor dust. The repeated samples were taken over a time period of about 6 years. We investigated the repeatability over time of their concentrations by determining correlation coefficients and computing within- and between-home variance components. Our analysis was based on the population of a study on Indoor Factors and Genetics in Asthma (INGA) being carried out in 1995/96 and followed up in 2000/01. Complete data were available from 152 participants. The measured allergen concentrations were low and a considerable percentage of the values was below the limit of detection. The crude Spearman's rank correlation coefficients between the two measurements taken in 1995/96 and 2000/01 ranged from 0.32 to 0.61 for the dust mites allergens, from 0.21 to 0.44 for cat allergen and from 0.35 to 0.51 for endotoxin. Correlations were higher if measurements were performed on the same floor or the same mattress at both sampling time-points. The within-home variance for all measured biocontaminant concentrations was of about the same order as the between-home variance. For studies like ours with low allergen and endotoxin concentrations, the repeatability of these concentrations over a time period as long as 6 years is low and a single measurement does not accurately reflect the true long-term exposure in the homes. [ABSTRACT FROM AUTHOR]

Allergen exposure is a risk to develop an IgE-mediated sensitization. The amount of allergen inhaled per unit time should be related to the amount present in the air, i.e. airborne allergen. Thus, measuring allergen levels in the air would be more relevant than measuring allergen levels in dust. Allergens are present in the air in very minute quantities and usually become airborne after disturbance. Large variation of allergen levels have been found in dust. In this study, we measured variability of airborne cat allergen, Fel d1, in a public place using a high-volume air-sampler. We also studied the distribution and relationship between dust and airborne cat allergens in homes and schools. Air samples were collected at three different airflow rates, i.e. 55, 40, and 30 m3 of air per hour. The concentration of airborne Fel d1 in the community gymnastic hall varied from 1 to 10 pg/m3 within a period of 3 weeks, at airflow rates 55–30 m3/h. The coefficient of variation for repeated samplings was 14–43% (day-to-day variation) and 27–38% (within-day variation). As expected, higher levels of airborne cat allergens were found in homes with cats than in cat-free environments. There was a significant relationship between cat allergen levels in dust and air ( r = 0.7, P < 0.01). Our study demonstrates that when measuring airborne cat allergen a large variation is observed within a day and between days. The large variability of measurement may be explained by the disturbance in the environments. We suggest, that when exposure assessment is made the environment in question should be analyzed, if possible in several occasions. Airborne cat allergens are associated with the levels of cat allergen in the dust. Cat allergens are commonly found in the public places where these animals are never kept. Thus, it seems that cat allergens are brought to public places in the clothes of people who have cats at home. The levels of allergens vary both within a day and day-to-day depending on the number of people visit this area. Outdoor clothing and shoes must be avoided in order to achieve allergen-free gymnastic halls. [ABSTRACT FROM AUTHOR]

An immunochromatographic method for qualitative and quantitative determination of aeroallergens direct on sampling (ADOS) filters has been developed. In this method, a porous polytetrafluoroethylene filter carrying adsorbed allergens is fixed by double-coated adhesive tape to a supporting filter paper matrix. Following addition of antibodies specific for the relevant allergens and washing and staining reagents via a reagent applicator an immunochromatogram is developed resulting in a 5–10 mm wide area of the sample filter covered with blue-violet-stained spots appearing on a faintly pink or white background. The method takes 30 to 90 min, depending on the nominal porosity (1.2–5 μm) and the defined reaction area (5–10 mm) of the sample filter. Application experiments with birch and grass pollen, soluble Bet v 1, Phl p 5 and mould allergens as well as cat allergen carried by airborne dust revealed a limit of detection of a few picograms of allergen as stained spots. The specificity of the new method to evaluate the type of allergen is a function of the selected antibodies. The concentrations of the allergen in an air sample are related to the number and intensity of stained spots. [Copyright &y& Elsevier]

The increasing frequency of pet ownership (especially cats) in many industrialized countries has raised the level of exposure to the allergens produced by these animals. Moreover, it is likely that modern energy-saving systems and the wide use of upholstered furniture has resulted in closer contact between cats (and their allergens) and humans. Many different methods have been developed to quantify the main cat allergen (Fel d 1) in settled dust and in ambient air. The threshold levels of cat allergen inducing sensitization or triggering respiratory symptoms in sensitized patients have been calculated in settled dust, but airborne amounts of Fel d 1 probably represent a more reliable index of allergen exposure. Noticeably, the amount of Fel d 1 may be relatively high also in confined environments where cats have never been kept. It has been demonstrated that clothes of cat owners are the main source for dispersal of allergens in cat-free environments. This fact may be of relevance, because recent studies have shown that allergic sensitization to cats is more likely to develop in children exposed to moderate levels of this allergen than in children exposed to high amounts of Fel d 1. The ubiquity of cat allergen may justify the common observation that allergen avoidance is often insufficient to reduce the risk of developing allergic sensitization and/or symptom exacerbation in highly susceptible patients. Further efforts are needed to improve the efficacy of Fel d 1 avoidance strategies to try to reduce the risk of allergic sensitization to this allergen.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Summary Background Domestic air filtration units have previously been shown to cause a dramatic fall in airborne pet allergen levels in homes with pets. Clinical trials of air filtration units, however, have failed to reveal a significant beneficial effect. Personal pet allergen exposure during air filtration unit use has never been measured. Objective To determine the effect of air filtration on inhaled cat allergen exposure in homes with cats. Methods Nasal air samplers were worn to measure personal cat allergen exposure. The study was carried out in five homes with cats on 4 separate days examining four experimental conditions (cat absent or present, air filtration off or on). The two operators collected four baseline samples and two 15-min samples/h over three consecutive hours. Cat allergen-bearing particles were detected by immunoblotting and allergen concentrations measured by amplified enzyme-linked immunosorbent assay (ELISA). Results There was a significant reduction in the quantity of the inhaled Fel d 1 when the air cleaner was used with the cat in the room. Fel d 1 halo counts (detransformed means) were 29.3 at baseline, 11.8 after 1 h, 10.0 after 2 h and 14.1 after 3 h, with no change on control days (P = 1.00). With the cat elsewhere in the house, a marginal, but statistically significant reduction was observed only after 3 h with the use of air cleaner (Fel d 1 halo count: baseline 12.4; 3 h 5.5; P = 0.01). Conclusions The use of air filtration units appears to result in a much smaller reduction of inhaled cat allergen exposure than suggested by previous studies using standard air samplers. Cat removal remains the best advice to cat-allergic patients who experience symptoms upon exposure. [ABSTRACT FROM AUTHOR]

Background: Recent cross-sectional studies suggested that highest sensitization prevalences occur with moderate cat allergen exposures. We aimed to assess the impact of moderate levels of second-hand cat allergen exposure on the incidence of specific sensitization and wheezing in the framework of a birth cohort study. Therefore we restricted our analysis to infants without a cat at home since birth. Methods: At infant's age 3 months, cat allergen levels were measured in the mattress dust of 1840 families without cats. At age 2 years, serum IgE specific to Fel d 1 was analyzed. Incidence of wheezing apart from respiratory infection was assessed by questionnaire. Logistic regression models were used to calculate adjusted odds ratios (OR) for the association between second-hand cat allergen exposure and health outcomes. Results: Until age 2 years, 13 of 1301 infants (1%) were sensitized to cat allergen and 56 of 1492 infants (4%) had ever-wheezing without infection. Early exposure to second-hand cat allergen levels ≥ 1 µg/g dust increased substantially the risk for specific sensitization to Fel d 1 (OR 10.9, 95% CI 3.4–35.0) and ever-wheeze without infection (OR 2.0, 95% CI 1.1–3.9) at age 2 years. Conclusions: Second-hand exposure to cat allergen in homes without cats is detrimental in terms of allergy development in infants. [ABSTRACT FROM AUTHOR]

Few teams have studied the effects of particle size on the bronchial response to inhaled allergen. Nonetheless, the aerodynamic characteristics of the particles carrying allergens may explain some of the differences observed between bronchial responses to different allergens, between responses during bronchial provocation tests (BPT) and to responses under realistic conditions. We have shown that the dose of allergen inducing symptoms in BPT is 20 times smaller when cat allergen is carried by particles measuring 10.3 μm in aerodynamic diameter than when carried by particles measuring only 1.4 μm. Accordingly, the immediate bronchial response to cat allergen appears to be localized in the proximal airways and should be studied in BPT with particles of 10 μm diameter. [Copyright &y& Elsevier]

Increasing asthma prevalence is evident in many countries and childhood asthma has also become one of the most common chronic diseases in children. Exposure to indoor allergens has been be attributed to a significant increase in asthma occurrence. Meanwhile, allergen distribution varies widely among different countries. This brief investigation reports the distribution of common indoor allergens, such as mite (Dermatophagoides pteronyssinus, Der p 1 and Der p 2), cat (Felis domesticus, Fel d 1), and German cockroach allergens (Blattella germanica, Bla g 1) at different sites of asthmatic children in Taiwan. Approximately 40 asthmatic children''s homes participated in this study and the cohort was followed prospectively for approximately 6 months, starting in December until the following May. Dust samples were collected from each child''s mattress, and bedroom and living room floors. All samples were analyzed with monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA). Statistical difference of Der p 1 concentrations is observed among those on the mattress, bedroom and living room floor, except for in May. Seasonal variation in Der p 1 levels on the mattress and bedroom floor is also significant (P<0.025 and 0.001, respectively). Distributional variation seems to be significant for most allergens among sites within homes in most seasons. Therefore, if only one sample is to be taken, the month of May would be a more ideal choice of study period, and detailed sampling across sites appears to be necessary should the true environmental exposure of allergens be desired. [Copyright &y& Elsevier]

Background: Exposure to furred pets in early life has been considered to increase the risk of allergic sensitization and consequent development of asthma later in children. However, recently, it has been suggested that early exposure to pets prevents sensitization. The aim of this study was to evaluate the importance of early exposure to pets and other environmental risk factors in asthmatic children. Methods: This is a follow-up study after 2 years of a previously investigated group of 193 asthmatic children, aged 1–4 years. The study was completed by 181 children, who were clinically examined; serum IgE antibodies were also measured and a questionnaire was answered. Results: Children with reported exposure to cats during the first 2 years of life were more likely to have developed sensitization to cat by 4 years of age than unexposed children. High levels of cat allergen (Fel d 1≥8 µg/g dust) were associated with an increased risk of sensitization to cat and, in combination with tobacco smoke, also with the development of more severe asthma. Conclusions: In young asthmatic children, early exposure to cat and tobacco smoke increased the risk of allergic sensitization and further development of more severe asthma later in childhood. [ABSTRACT FROM AUTHOR]

Exposure to foreign antigens is an essential element of all immune responses, including allergic sensitization. For some allergens (e.g. mite and cockroach), the prevalence of sensitization is directly correlated with exposure. However, for allergens derived from domestic animals, several studies have suggested that children with a cat in the home have a decreased risk of sensitization and asthma. We have now shown that many children exposed to greater than 20 μg of Fel d 1/g of dust at home made an IgG and IgG4 antibody response to Fel d 1 without IgE antibody. This modified Th2 response is not associated with symptoms and should be regarded as a form of immunological tolerance. The fact that the dose-response relationship between cat exposure and sensitization is bell shaped, while that for mite exposure and sensitization is linear, is highly relevant to understanding the role of allergens in the increase in allergic disease.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

xxBackground: Measurement of airborne allergens has hitherto been done with the use of fixed-location pumps or personal air samplers. Our objective was to find out whether ionizers could be good tools for collecting airborne allergens. As a model we have used cat allergen (Fel d 1). We have compared Fel d 1 levels collected by the ionizer at different time periods, as well as comparing Fel d 1 levels obtained with the ionizer with those of low- and high-volume pumps. Methods: Dust samples from floors and air samples collected with ionizers and pumps, obtained in 31 homes with cat, 23 homes without cats, and 28 day-care centres, were analysed for cat allergen content (Fel d 1) by ELISA. Results: Fel d 1 was present in the reservoir in all homes with cats, ranging from 660 to 375000 ng/g (GM 75000) and in the air collected by the ionizer from 2.0 to 204 ng/24 h (GM 19.3). The allergen in homes without cat varied from <55 to 1800 ng/g (GM 166). Corresponding levels in air were found in two of these homes (2.3 and 7.3 ng/24 h). There was a correlation between the number of cats and the amount of airborne cat allergen (r: 0.47; P<0.05). The levels in day-care centres were <55 to 3070 ng/g in dust (GM 360) and <1.1 to 7.9 ng/24 h in the air (GM 1.6). We obtained a moderately strong correlation between air and dust samples in homes with cats (rs: 0.64; P<0.001) and in day-care centres (rs: 0.49; P<0.05). We found that a collection period of 24 h is preferable for the ionizer. The intrahome reliability coefficient was nearly two times higher for the ionizer (r: 0.69) than the pump (r: 0.39). Conclusions: The ionizer seems to be a good tool for monitoring the environment. It is easy to use and silent and does not disturb the airflow in the room. [ABSTRACT FROM AUTHOR]

Genome engineering with clustered regularly interspaced short palindromic repeats (CRISPR) technology offers the unique potential for unequivocally deleting allergen genes at the source. Compared to prior gene editing approaches, CRISPR boasts substantial improvements in editing efficiency, throughput, and precision. CRISPR has demonstrated success in several clinical applications such as sickle cell disease and β-thalassemia, and preliminary knockout studies of allergenic proteins using CRISPR editing show promise. Given the advantages of CRISPR, as well as specific DNA targets in the allergen genes, CRISPR gene editing is a viable approach for tackling allergy, which may lead to significant disease improvement. This review will highlight recent applications of CRISPR editing of allergens, particularly cat allergen Fel d 1, and will discuss the advantages and limitations of this approach compared to existing treatment options., Competing Interests: MC is a co-owner and founder of INDOOR Biotechnologies Inc. NB and AP are employees of INDOOR Biotechnologies Inc., (Copyright © 2022 Brackett, Pomés and Chapman.)

Background: Earlier studies have shown that farmers are to a low degree sensitized to animal allergens. We have measured the amount of cat (Fel d 1) and dog (Can f 1) in farm households and examined the relationship between exposure and sensitization to cat and dog allergens. Methods: Dust samples from the homes of 403 farmers who had participated in an epidemiologic follow‐up study on respiratory symptoms were analyzed for allergen content by two‐site ELISA methods. Results: Fel d 1 was detected in 99.5% of the farmers' households ranging from 0.055 to 1455 μg/g dust in mattresses (GM 13.2) and to 3775 μg/g dust in living‐room carpets (GM 17.1). Can f 1 was detected in 90.6% of the households from 0.2 to 116 μg/g dust in mattresses (GM 2.0) and to 504 μg/g dust in carpets (GM 4.3). Homes with pets present had the highest levels of the allergens (P<0.001). A total of 8.4% and 7.4% of the farmers were sensitized to cat and dog, respectively. A significant correlation was noted between exposure to the allergens and specific IgE to cat and dog, respectively (P<0.001). Sensitization to cat (OR=4.9) and dog (OR=17.8) was significantly associated with asthma. Conclusions: In spite of the abundance of Fel d 1 and Can f 1, farmers are only to a low degree sensitized to cats and dogs. [ABSTRACT FROM AUTHOR]

BackgroundCat allergy is common among children with asthma. Many cat-allergic patients in Japan and elsewhere do not keep cats, but nonetheless become sensitized through environmental exposure to cat allergen. ObjectiveTo assess the frequency of cat allergy and cat-specific immunoglobulin E (IgE) and immunoglobulin G (IgG) antibody responses in young Japanese patients with asthma in relation to self-reported cat exposure and Fel d 1 levels in dust samples. MethodsCat dander-specific IgE antibody was measured in sera from asthma patients using the CAP system. IgE and IgG antibody to Fel d 1 was measured by antigen binding radioimmunoassay and by chimeric enzyme immunoassay. Fel d 1 levels in dust samples from a subset of patients' homes were measured by monoclonal antibody-based enzyme immunoassay. ResultsCat-specific IgE (CAP class≥2) was found in sera from 70% of 44 patients who kept cats and 34% of 394 patients who had never kept cats. The prevalence of sensitization increased progressively to age 6 years (40%: positive), and then increased gradually to age 16 years (approximately 60%: positive) in patients who had never kept cats. There was an excellent correlation between cat CAP values and IgE levels to Fel d 1. The absolute amount of IgE antibody to Fel d 1 ranged from 0.01 to 15.6% of total IgE. Most patients who did not keep cats were exposed to Fel d 1 levels ranging from 0.07–8 μg/g dust. ConclusionsSensitization to cat allergen is common among young asthmatic patients in Japan, even among patients who do not keep cats. Use of CAP and the chimeric enzyme-linked immunosorbent assay allows accurate diagnosis of cat allergy and quantification of specific IgE antibody levels. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether repeated exposure to subclinical doses of cat allergens, not inducing asthma symptoms, could affect eosinophil cationic protein (ECP) levels in bronchoalveolar lavage (BAL) or in peripheral blood, without the appearance of clinical symptoms. Twelve patients with mild asthma, all sensitized to cats and not exposed to cat allergen at home, underwent a series of inhalations of cat allergen or placebo for 8 days over 2 weeks. A methacholine challenge was performed before and after the allergen and saline exposures, and BAL and blood were sampled for ECP measurements and eosinophil counts. No patients experienced asthma symptoms. However, PD20 methacholine (geometric mean) decreased significantly from 263 μg before to 126 μg after inhalation of allergen. Inhalation of saline did not induce any significant change in PD20. The change in log PD20 before and after cat allergen exposure was statistically different from the change in log PD20 before and after saline. Median ECP levels in BAL and serum increased significantly after allergen exposure, from 0.8 to 3.1 μg/l (p<0.02) and from 15.9 to 31.4 μg/l (p<0.05), respectively. No change was observed after saline inhalations. The change in BAL and serum ECP levels was statistically significant compared to that in the control group. The number of eosinophils did not change, however, nor did IL–5 and RANTES levels in BAL and serum. In conclusion, our results show that (1) exposure of asthma patients to repeated low doses of allergen, which did not provoke any clinical symptoms, is capable of inducing a local eosinophil activation associated with an increase in nonspecific bronchial hyperresponsiveness and (2) the increase in serum ECP levels due to eosinophil activation precedes the occurrence of asthma symptoms and may thus be a marker of allergen exposure in allergic asthma. [ABSTRACT FROM AUTHOR]

Background Poor indoor air quality has been suggested to be related to the increase in the prevalence of asthma that has occurred in the western world, especially among children and young persons. Apart from the home, school is the most important indoor environment for children. Objectives The aims were to study the prevalence of current asthma among secondary pupils and its relationship to the school environment, but also to personal factors and domestic exposures. Methods Data on asthmatic symptoms, other health aspects, and domestic exposures were gathered using a questionnaire which was sent to 762 pupils in the seventh form (13-14 years old) in 11 randomly chosen schools in the county of Uppsala in Sweden. Pupils answering `yes' to having had asthma diagnosed by a physician, and having had recent asthma attacks, or who used asthma medication were defined as having current asthma. Data on exposures at school were gathered by measurements in 28 classrooms. The relationship between asthma and exposures was analysed by multiple logistic regression. Results The questionnaire was completed by 627 (82%). Current asthma was found among 40 pupils (6.4%). Current asthma was more common in those who had an atopic disposition, or food allergy, or who had attended a day care centre for several years. Controlling for these factors, current asthma was related to several factors in the school environment. There were more pupils with current asthma in schools that were larger, had more open shelves, lower room temperature, higher relative air humidity, higher concentrations of formaldehyde or other volatile organic compounds, viable moulds or bacteria or more cat allergen in the settled dust. Conclusions Although the pupils attended school for a minor part of their time, our study indicates that the quality of the school environment is of importance and may affect asthmatic symptoms. [ABSTRACT FROM AUTHOR]

Background It has been shown that a vacuum cleaner (VC) can increase airborne cat allergen levels. This study aimed to compare the degree of leakage of airborne Fel d 1 levels among five different VCs, both under laboratory conditions and in an apartment with cats. Methods Three of the VCs were marketed as antiallergic: a HEPA filter VC (VC A), a water impingement and HEPA filter VC (VC B), and a foam fabric filter VC (VC C). The other two were standard VCs: VC D and VC E. VCs were tested in a 20 m³, airtight, experimental room and in a 53 m³ living room in an apartment with three cats. Air was sampled with a glass-fiber filter and an impinger at 20 1/min for 30 min before, during, and after vacuuming. Airborne Fel d 1 was measured with a two-site monoclonal ELISA assay. Results In the experimental room, no airborne Fel d 1 level was measured before using the VCs. After introducing a dust sample containing Fel d 1 in the VCs. we found that VCs A, B, and E did not provoke any increase in airborne Fel d I. In contrast, VCs C and D significantly increased airborne Fel d 1 levels (GM: 4.9 and 5.3 ng/m³, respectively). In the apartment, all VCs induced an increase in airborne Fel d 1, which was carried by particles greater than 5 µm. However, VCs C and D provoked significantly greater increases in airborne Fel d 1 than VCs A, B, and E (P=0.0001). Conclusions Our results suggest that: 1) The two VCs with leakage in the experimental room had greater leakages in the apartment. 2) In the apartment with cats, all VCs provoked increases in airborne Fel d 1, primarily carried by large particles. 3) Given the increased marketing of "antiallergic" VCs, further studies are needed to standardize methods for testing airborne allergen leakage by VCs. [ABSTRACT FROM AUTHOR]

The major cat allergen Fel d I is a homodimer of which each monomer consists of two disulfide-linked polypeptide chains: chain 1 (70 amino acid residues) and chain 2 (92 amino acid residues). Twenty-one synthetic peptides of 14 arming acid residues length, overlapping by seven residues and spanning the entire sequence of both chains, were synthesized. These peptides were coupled to CNBr-activated Sepharose--4B and used as solid-phase antigens in epitope-mapping studies with monoclonal antibodies against native and reduced/alkylated Fel d I. Two monoclonal antibodies directed against reduced/alkylated chain 1 bound to the overlapping peptides 53-66 and 60-70 of chain 1. The monoclonal antibody directed against reduced/alkylated chain 2 bound to the overlapping peptides 36-49 and 43-56 of chain 2. Binding specificity was demonstrated by inhibition by reduced/alkylated Fel d I for all three monoclonal antibodies. Another monoclonal antibody against reduced/alkylated Fel d I had been found to bind predominantly to reduced/alkylated chain 2 on immunoblot in previous studies (27). It bound to peptides 1-16 and 60-70 of chain 1 and peptides 1-14 and 50-63 of chain 2; it is therefore probably directed against a conformational epitope formed by these four regions. Possibly because of low affinity of this monoclonal antibody, specificity of its binding could not be verified by inhibition studies. A panel of monoclonal antibodies directed against native Fel d I bound to peptides 1-16 and 60-70 of chain 1 and peptides 1-14 and 43-56 of chain 2. For two monoclonal antibodies, binding to each peptide was investigated and shown to be inhibitable by native Fel d I. These antibodies are therefore probably directed against a conformational epitope formed by these four regions. These studies give us substantial information about the quaternary structure of Fel d I. [ABSTRACT FROM AUTHOR]

The article discusses the survey on the possibility of cat allergen exposure on the passengers of the airlines in-cabin transportation of cats. It presents a table of the approved and banned airlines for the in-cabin transportation. It says that passengers should keep anti allergic drugs including carticosteroids, and epinephrine. It also says that allergen exposure also derive from many different sources including transportation of cat's owners clothing, and contaminated seats.

Background: The determination of house dust mite and cat allergens is a prerequisite for qualified assessment of exposure risk indoors. We describe the validation of integrated wipe tests comprising a porous sampling pin for the collection of settled house dust and an immunochemical test set-up for specific analysis of dust associated allergens. Methods: Wipe tests comprised an immunochromatographic test system and a porous sampling pin for collecting dust by manually wiping a surface. Two different wipe tests were developed with specificity to cat allergen (Fel d 1) and to dust mite allergen (Der p 2/f 2). One-hundred and fifty on-site determinations for each of the allergens in 50 different households completed the field study to validate the analytical system. Reference analysis was based on collection of dust with a vacuum cleaner and analysis of dust associated allergens by ELISA. Results: The wipe tests were found to produce semiquantitative results (class 0–3) on-site within 10 min of analysis time. For dust mite (cat) allergen the median of class 0–3 was 119 (263), 812 (844), 2708 (5670) and 8000 (56 800) ng/g dust, respectively. With respect to cut-off levels for dust mite (cat) allergens the clinical sensitivity was 62% (79%) and the clinical specificity was 94% (92%). Conclusions: The wipe tests proved to be a reliable tool for indoor allergen exposure screening, suitable for use even by untrained persons. This may have an impact on compliance with allergen avoidance measures. [ABSTRACT FROM AUTHOR]