Cockroach allergy and exposure to cockroach allergen in Polish children with asthma

BACKGROUND: Asthma morbidity increases every year, especially among children, and exposure to high levels of indoor allergens is a very important factor. We evaluated the prevalence and exposure to cockroach (CR) allergen in asthmatic children in Poland, and also tested the hypothesis that asthma with allergy to CR is more severe than with allergy to other antigens. METHODS: One hundred and sixty children with asthma were examined, had skin prick tests (SPT) with common and CR allergens, underwent spirometry, and provocation tests to histamine. Children with positive SPT to CR had measured specific IgE levels to this antigen and Bla g 2 concentrations were measured in their homes. RESULTS: The most common allergen, was dust mite 51.3%, followed by pollen 48.8% and CR allergen 24.3%. In children with CR sensitivity, 13% had mild asthma, 26% moderate and 61% had severe asthma. Their levels for forced expiratory volume in one second (FEV1), and the provocative concentration of histamine that caused a 20% fall in FEV1 (PC20), were statistically lower than in the group of children with other than CR allergies. Bla g 2 antigen was detected in 55.13% samples. The highest levels of Bla g 2 were found in old houses, without central heating, and in houses with lower income. CONCLUSION: In Polish children, CR allergen is a very important factor of sensitivity. Concentrations of Bla g 2 in homes are higher than previously reported in other European countries, and are strongly related to the houses' characteristics. Also, children with CR hypersensitivity have severe asthma more often than children with other allergies.     

Longitudinal study on the relationship between cat allergen and endotoxin exposure, sensitization, cat-specific IgG and development of asthma in childhood--report of the German Multicentre Allergy Study (MAS 90)

BACKGROUND: Controversial data have emerged regarding the question whether cat exposure in childhood favours or decreases the risk of sensitization and allergic airway disease. In a prospective birth-cohort study, we assessed the association between longitudinal cat allergen exposure, sensitization (immunoglobulin E, IgE), IgG antibody (ab) levels to cat and the development of asthma in children up to the age of 10 years. METHODS: Of 1314 newborn infants enrolled in five German cities in 1990, follow-up data at age 10 years were available for 750 children. Assessments included yearly measurements of specific serum IgE to cat and at age 6 and 18 months, 3, 4 and 10 years measurement of cat allergen Fel d 1 in house dust samples. Additionally, Fel d 1-specific IgG ab were determined in 378 serum samples of 207 children. Endotoxin exposure in mattress dust was measured in a subgroup of 153 children at age 10 years. From age 4 years on, International Study of Asthma and Allergy in Childhood (ISAAC) questionnaires were completed yearly in order to assess the prevalence of wheeze and asthma. RESULTS: Serum IgG-levels to cat showed a large variation, however, intraindividually values showed rather constant concentration over a longer time period. The IgG levels at school-age correlated with cat allergen exposure during the first 2 years of life. Specific IgE to cat was clearly associated with wheeze ever, current wheeze and bronchial hyperresponsiveness (BHR), this was also observed for children with specific IgE ab to cat (>0.35 kU/l) plus IgG levels above 125 U/ml. A large percentage of very highly exposed children showed high IgG but no IgE responses to cat, however, not all highly exposed children were found to be protected from sensitization. Children with IgG but without IgE ab to cat showed the lowest prevalence of wheeze ever and current wheeze despite high cat allergen exposure, however, this trend did not achieve significance. While homes of cat owners showed higher Fel d 1 concentrations than homes without cats, homes of cat owners were not found to have higher endotoxin levels in carpet dust samples than homes without cats. CONCLUSIONS: We could confirm that high cat allergen exposure in a cohort with lower community prevalence of cats is associated with higher serum IgG and IgE levels to cat in schoolchildren. Sensitization to cat allergen (IgE) is a risk factor for childhood asthma. While exposure to cat allergen during infancy is associated with sensitization (IgE), only in the very highly exposed children the likelihood of sensitization (IgE) is decreased and high IgG levels to cat without IgE were associated with low risk of wheeze. However, cat-specific IgG ab levels did not protect children with IgE-mediated sensitization from wheeze.     

Etiologic role of unapparent exposure in cat allergy

To determine the importance of unnoticed exposure to cat, we studied 20 patients with a history of respiratory allergy. All the patients had a positive prick test to cat dander extract, and none of them kept cats as pets. The prick test was carried out with a dander extract from cat at a concentration of 100 BU/ml. The specific IgE was determined by the commercially available Pharmacia CAP System. We carried out a conjunctival challenge test. The concentration of Fel d I was quantified in dust samples from the patients' homes by a commercially available method. The patients were reassessed in order to establish a relation between exposure and symptoms, and concealed allergen sources. Sixteen patients, showed significant levels of Fel d I in their homes (mean of 3.35 μg g of dust). The conjunctival challenge test was positive in 15 patients. These patients showed an exposure mean of 0.4 μg/g of dust. The mean levels of specific serum IgE were higher in those patients with a positive challenge than in those with a negative challenge ( P = 0.0145). In nine reassessed patients, a relation was established between natural exposure and the onset of the symptoms. A possible hidden allergen source was established in 11 patients. Hidden exposure to cat allergen may play a role in the symptomatology of many atopic patients, and investigation of sensitization to Fel d I should be included in the routine allergologic evaluation of all patients with asthma or perennial rhinitis.     

Does early exposure to cat or dog protect against later allergy development?

BACKGROUND: It is unknown which factors in modern western society that have caused the current increase in prevalence of allergic diseases. Improved hygiene, smaller families, altered exposure to allergens have been suggested. OBJECTIVES: To assess the relationship between exposure to pets in early life, family size, allergic manifestations and allergic sensitization at 7-9 and 12-13 years of age. METHODS: The prevalence of allergic diseases and various background factors were assessed in 1991 and 1996 by questionnaire studies. In 1991, the study comprised representative samples of children from the G?teborg area on the Swedish west coast (7 years old, n = 1649) and the inland town Kiruna in northern Sweden (7-9 years old, n = 832). In 1992, a validation interview and skin prick test (SPT) were performed in a stratified sub-sample of 412 children. In 1996, this subgroup was followed up with identical questions about clinical symptoms as in 1991, detailed questions about early pet exposure were added and SPT performed. RESULTS: Children exposed to pets during the first year of life had a lower frequency of allergic rhinitis at 7-9 years of age and of asthma at 12-13 years. Children exposed to cat during the first year of life were less often SPT positive to cat at 12-13 years. The results were similar when those children were excluded, whose parents had actively decided against pet keeping during infancy because of allergy in the family. There was a negative correlation between the number of siblings and development of asthma and allergic rhinitis. CONCLUSION: Pet exposure during the first year of life and increasing number of siblings were both associated with a lower prevalence of allergic rhinitis and asthma in school children.     

Wheat allergen exposure and the prevalence of work-related sensitization and allergy in bakery workers

Background: Occupational airway diseases are common among bakers. The present study describes the association between exposure to wheat allergen levels and sensitization to wheat allergens, work‐related upper and lower respiratory symptoms and asthma in bakery workers. Methods: As part of a Health Surveillance System for early detection of (allergic) occupational airway diseases a so‐called ‘validation study’ was performed among Dutch bakers for validation of a diagnostic model that predict the likelihood of sensitization to specific workplace allergens. The present study used serology and questionnaire results of a subgroup of 860 bakers participating in the validation study. An earlier developed job‐exposure matrix was used to predict average and cumulative personal exposure to wheat allergens. Results: The prevalence of wheat sensitization, work‐related respiratory symptoms and asthma increased till average wheat exposure levels of approximately 25–30 μg/m³, leveled off and decreased at higher exposure concentrations. Exposure–response curves showed a stronger pronounced bell‐shape with cumulative exposure. Associations were strongest for asthma and work‐related lower respiratory symptoms (PR∼2 and PR∼3.5–4.5 for average and cumulative exposure, respectively). Associations were only found in atopics. Wheat sensitization was an important factor in the prevalence of respiratory symptoms. Conclusion: In accordance with earlier studies, the present study showed a bell‐shaped exposure–response relationship especially for cumulative wheat allergen exposure with sensitization, allergic respiratory symptoms and asthma. The healthy worker effect may be the possible explanation for the bell‐shaped relationship.     

Mite and cat allergen exposure in Brazilian public transport vehicles.

BACKGROUND: Mites and pets are important sources of indoor allergens. OBJECTIVES: To determine Dermatophagoides pteronyssinus (Der p 1), Dermatophagoides farinae (Der f 1), and Felis domesticus (Fel d 1) allergen levels in buses and taxis and to evaluate the predominant allergen in each vehicle type. METHODS: Mite and cat allergens were measured using enzyme-linked immunosorbent assay in dust samples collected from upholstered seats in 60 natural-ventilation buses (NVBs), 60 artificial-ventilation buses (AVBs), and 60 taxis. Thirty dust samples from AVB air-conditioning filters were also included. RESULTS: Levels of Der p 1 and Der f 1 were significantly higher in AVBs than in NVBs, whereas Fel d 1 levels were not significantly different between bus types. No significant differences were found in mite allergen levels in various sites in both types of buses, whereas Fel d 1 levels were significantly higher in rear and middle seats than in front seats in NVBs. Mite and cat allergen levels in taxis were significantly higher in passenger's rear seats than in driver's seats. A high proportion of dust samples from the vehicles, especially AVBs (82% for Der p 1 and 58% for Der f 1) had sensitizing levels of mite allergens, whereas more than 60% of samples from all vehicles had sensitizing levels of Fel d 1 allergen. In AVBs, samples from seats showed significantly higher levels of mite and cat allergens than those from air-conditioning filters. CONCLUSIONS: Public transport vehicles constitute an important allergen reservoir for continuous contamination of the indoor environment.     

Longitudinal study of the cognitive development in children with Williams-Beuren syndrome

Crisco [1990: Clin Res 38:536A] reported stability of IQs in a group of 14 children with Williams-Beuren syndrome (WBS) over a 5-year period and concluded that they display a development rate similar to normal children. The aim of our study was to examine the stability of the development of nonverbal reasoning abilities over a period of 2 years using two methods. We studied 18 children with WBS (9 girls, 9 boys) with a mean age of 6.6 years (range: 4.4–10.6 yr) at year one (T1), and approximately two years later (T2) at the average age of 8.6 years (range: 5.11–12.7 yr). The Columbia Mental Maturity Scale (CMM) and the Draw A Person Test were administered. The results show that the IQs resulting from the Draw A Person Test were stable over the 2-year period (T1: mean IQ = 63.5, T2: mean IQ = 65, t = 0.63), and display a significant correlation between the two methods (r = 0.547, P = 0.01). Furthermore, the correlation between the two tests (CMM and Draw A Person Test) at the second assessment is high and significant (r = 0.56, P = 0.01). The mean IQs at T2 can be classified as mild mental retardation. A notable result is the significant decrease of the IQs according to the CMM (T1: mean IQ = 77, T2: mean IQ = 68, t = 2.69, P = 0.01). These results suggest that the developmental outcome of children with WBS varies in specific areas of cognitive function over a 2-year period. © 1995 Wiley-Liss, Inc.     

Human hair: an unexpected source of cat allergen exposure

BACKGROUND: Cat allergens are ubiquitous because the clothing of cat owners constitutes an important source of distribution of Fel d 1 in cat-free environments. Since Fel d 1 can adhere to a variety of surfaces, we sought to verify if human hair belonging to individuals with or without a cat at home might represent a reservoir and be a possible carrier of cat allergens. METHODS: Seventy-three women (25 with a non-neutered male cat and 25 with a dog at home, and 23 controls without any direct contact with these animals) were recruited. The collection of material from hair was carried out using a modified version of a battery-powdered portable sampler. Particulate material was harvested onto glass fiber filters (25 mm in diameter, with a pore size of 2 microm; AP 20 Millipore, Milan Italy), extracted in phosphate buffer with BSA and then assayed for the evaluation of cat allergen using an ELISA based on anti-Fel d 1 monoclonal antibody. RESULTS: Detectable levels of cat allergen were found in 2 controls, in 2 women with a dog at home and in 13 women with a cat at home, respectively. CONCLUSIONS: In some women with a cat at home, hair constitutes a significant reservoir of Fel d 1. It is likely that these amounts of cat allergen might contribute to allergic sensitization when released in cat-free environments.     

A prospective study of allergy development in 158 children and 128 adults with new extensive exposure to furred animals

BACKGROUND: There is still controversy over whether exposure to furred animals increases or decreases the risk of developing sensitization and allergic symptoms to such animals, and there is a need for further knowledge on this subject. OBJECTIVE: The aim of this study was to follow allergy development in relation to new extensive exposure to furred animals in adults and children. METHODS: A total of 286 individuals, 128 parents and 158 children, were recruited from 68 families who intended to buy a dog or a cat, or where one child of the family intended to start riding a horse. Subjects were examined before the new allergen exposure and once a year thereafter for 5 years, in all at six occasions, and they also completed questionnaires covering allergy symptoms. Serum IgE antibodies to cat, dog and horse were determined each year, and fur allergens from beds and living rooms were analysed. RESULTS: Two-hundred and fifty-six study subjects remained for evaluation, 37 of whom showed signs of allergic sensitization at the start of the study. Four children (11%) in this pre-sensitized group developed IgE antibodies to their new animal and six (16%) to another animal. Among the 219 participants who were not sensitized when entering the study, one male adult (0.4%) developed a sensitization to his new animal, and nobody developed sensitization to other animals. Pre-sensitized individuals had significantly more allergic symptoms at the study start, but the symptom scores did not change over time. CONCLUSIONS: When the first year of a human's life has passed, we have no strong evidence to recommend avoidance of a domestic animal in order to prevent new allergy development, even if there are known allergies in the family or if the individual is sensitized and has allergic symptoms to another allergen. Five years exposure to new fur allergens does not seem to influence sensitization to these animals in either sensitized or non-sensitized children and adults.     

The frequency and severity of cat allergy vs. dog allergy in atopic children

Questions were put to parents accompanying 1238 children, 1 to 17 yr old, who had symptoms of respiratory tract allergy. Skin prick tests were then performed. Symptoms after exposure to cats and positive skin test results from cat hair extract were significantly more frequent than symptoms after exposure to dogs or reactions to dog hair extract. The prevalence of symptoms and positive skin test reactions to cat allergens increased with age, significantly more so than the reaction or symptoms after exposure to dog allergens. The greater frequency of sensitivity to cats was not caused by exposure to cats in more homes, since dogs significantly outnumbered cats as the household pet in both atopic and nonatopic families. However, greater intimacy of exposure to cats when they were present may have been a factor because cats, significantly more often than dogs, were inside the house and in the child's bedroom. Two subgroups were examined to determine whether those with cat sensitivity who owned cats had more severe symptoms than those with dog sensitivity who owned dogs. Numbers were small and differences not statistically significant, but those in the cat subgroup more frequently had persistent allergic nasal symptoms and abnormally low spirometric measurements than did those in the dog subgroup. Our findings indicate that children are more often allergic to cats than to dogs and suggest that the greater frequency of sensitization to cats may be due to increased intimacy of exposure to cats.     

Different effects of endotoxin versus mite and cat allergen exposure on T-cell differentiation in infants

BACKGROUND: Early exposure to bacterial endotoxin has been proposed to protect against allergy development in children. Whether endotoxin is able to direct T-cell differentiation into a predominance of type 1 immunity is still unresolved. OBJECTIVE: We sought to compare the effects of endotoxin and mite and cat allergens on T-cell differentiation in infants. METHODS: In a random population sample of 135 2-year-old children of an ongoing birth-cohort study, peripheral blood CD4+ and CD8+ T-cell subsets were defined by the expression of the chemokine receptors CCR5 and CCR3 as surrogate markers for type 1 and type 2 T cells, respectively. Endotoxin and mite and cat allergens were measured in house dust collected from the mother's mattress at the child's age of 3 months to assess early exposure. RESULTS: In the CD4+ T-cell subset, endotoxin levels were positively associated with high proportions of type 1 CCR5+ cells (odds ratio for fourth exposure quartile [OR(Q4)], 7.68; 95% CI, 1.35-43.75), whereas cat allergen levels were associated with increased proportions of type 2 CCR3+ cells (OR(Q4), 4.07; 95% CI, 1.05-15.85). In contrast to endotoxin, allergen levels were associated with CD8+ T cells, showing an inverse relationship between mite allergen concentrations and high proportions of CCR5+ or CCR3+ cells (CCR5+ cells: OR(Q4), 0.14; 95% CI, 0.03-0.74; CCR3+ cells: OR(Q4), 0.16; 95% CI, 0.03-0.89) and a positive association of cat allergen levels with increased proportions of CCR5+ cells (OR(Q4), 9.24, 95% CI, 1.61-53.10), as well as CCR3+ cells (OR(Q3), 6.64; 95% CI, 1.21-36.51). CONCLUSION: Our results indicate that endotoxin has the potential to promote the development of type 1 CD4+ T cells, whereas mite and cat allergens primarily modify the proportion of CD8+ cells of both types.     

The prevalence of allergy to egg: a population-based study in young children

BACKGROUND: The aim of the present study was to estimate the prevalence of adverse reactions to egg, as population-based prevalence estimates based on objective diagnostic procedures are lacking. METHODS: The parents of 2721 children in a population-based birth cohort completed questionnaires on the occurrence of any reaction to food at 12, 18, and 24 months of age. Children with parentally reported reactions to eggs at the age of 2 years were selected for further examination. A stepwise diagnostic procedure was developed that included diet trials at home, skin prick tests, and open and double-blind, placebo-controlled food challenges. The mean age of the children at the time of the examination was 2.5 years (CI 2.5-2.6). A sample of children without perceived reactions to egg was also selected for assessment of unrecognized reactions. RESULTS: The estimated point prevalence of allergy to egg in children aged 2(1/2) years was 1.6% (CI 1.3-2.0%), with an upper estimate of the cumulative incidence by this age calculated roughly at 2.6% (CI 1.6-3.6). Almost all reactions were IgE mediated. In general, two-thirds of the parentally perceived reactions were verified. However, the positive predictive value of a parentally perceived reaction depended on the number of times it had been reported, and increased from 50% to 100%, for reactions reported one and three times, respectively. Unrecognized reactions were infrequent. CONCLUSION: This study confirms that allergy to egg is frequent in a child population.     

Haemagglutinating antibodies to cat dander in relation to exposure and respiratory allergy

Cat epithelial extract was coupled with chromic chloride to red cells and used as an antigen in a haemagglutination assay. Agglutinins coexisted with IgE type antibodies in 44% of patients with respiratory allergy and sensitivity to cat dander but occurred in only 1% of asthmatic patients sensitized to other allergens or in controls. The agglutinins were detected in six out of 104 cat fanciers, and three of those with agglutinins had asthma. The agglutinins were of IgG type and were heterogeneous in specificity.     

Small airways response to naturalistic cat allergen exposure in subjects with asthma

BACKGROUND: It is currently unclear whether the small airways (diameter <2 microm) contribute significantly to late asthmatic reactions to inhaled allergen. OBJECTIVES: We sought to determine whether naturalistic exposure to cat allergen induced late responses in the small airways as measured by pulmonary function testing and high-resolution computed tomography (HRCT) of the chest performed at end-expiration. METHODS: In a group of 10 subjects with cat-induced asthma, physiologic studies (spirometry and lung volumes, including closing volume) and HRCT were performed before and 6 and 23 hours after a cat room challenge that caused a 20% or greater acute fall in FEV(1). RESULTS: There was no significant decline in FEV(1) at 6 or 23 hours after cat exposure. Forced expiratory flow at 25% to 75% of forced vital capacity was significantly decreased at 6 hours after the challenge and returned to normal by 23 hours. HRCT image analysis as well as closing volume demonstrated increased air trapping from baseline at both 6 and 23 hours after the challenge. In addition, image analysis demonstrated a significant increase in small airways hyperresponsiveness to methacholine at 23 hours after the challenge. No significant mean changes were noted in lung volumes at either 6 or 23 hours or in PC(20) FEV(1) at 23 hours postchallenge. CONCLUSION: These findings demonstrate that naturalistic exposure to cat allergen results in significant small airways obstruction and hyperresponsiveness persisting for at least 23 hours, at which time these changes cannot be detected by conventional physiologic measures. CLINICAL IMPLICATIONS: Physiologically silent distal lung inflammation persists after an antigenic challenge.     

The effect of reducing levels of cat allergen (Fel d 1) on clinical symptoms in patients with cat allergy.

BACKGROUND: Treatment of cat allergy normally entails removal of the cat from the household, but cat owners are often unwilling to part with their pets, despite clinically relevant allergies. OBJECTIVE: To determine whether levels of Fel d 1 can be reduced without removal of the cat and whether this will affect symptoms of cat allergy. METHODS: Cat-allergic patients underwent randomization to either a group instructed in environmental control (EC) and a group with unchanged environment (UE). Dust samples were obtained and settled Fel d 1 measured by enzyme-linked immunosorbent assay. Patients recorded daily nasal inspiratory flow rates. At baseline, 3 months, and 8 months, patients underwent symptom evaluation. RESULTS: Eighteen patients were randomized to the EC group and 22 to the UE group; the final number completing the study was 31, 15 in the EC group, and 16 in the UE group. At 8 months, home Fel d 1 levels had diminished to 6.8% of baseline levels in the EC group, whereas no reduction in levels was noted in the UE group. In the EC group, significant improvements were found in nasal inspiratory flow rate and symptoms compared with the UE group. Patients did not have difficulties adhering to EC measures. CONCLUSION: A decrease in the allergen load was found in the EC group, which had a significant effect on symptoms of nasal allergy.     

Health impacts of second-hand exposure to cat allergen Fel d 1 in infants

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 >or= 1 microg/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.