Atopy patch testing in children with asthma and rhinitis symptoms allergic to house dust mite

The atopy patch test (APT) is generally used to assess immunoglobulin E (IgE) mediated sensitization to allergens in patients with atopic dermatitis, but its diagnostic role in children with respiratory allergy is still controversial. The aim of the study was to evaluate APT with house dust mite (HDM) in children with asthma and rhinitis symptoms allergic to HDM and its relevance to skin prick test (SPT) diameters and specific IgE levels. The study population consisted of 33 children, aged 8-16 yr (median: 12 yr) with asthma and 30 children with allergic rhinitis in the same age range (median: 11 yr). All patients had positive SPT results and high serum specific IgE levels for Dermatophagoides pteronyssinus APT was performed on back skin of all patients with 200 index of reactivity (IR)/ml of D. pteronyssinus allergen extracts in petrolatum (Stallerpatch) and evaluated at 72 h. Of 63 patients, 16 (25%) showed a positive patch test result. APT with HDM showed 30% (10/33) positivity among the patients with asthma and 20% (6/30) positivity among the patients with allergic rhinitis. APT presented no significant correlation with age, SPT diameter, serum total and specific IgE levels for D. pteronyssinus, nasal provocation test or pulmonary function test results. Patch testing with HDM may partly identify mite sensitive children with respiratory allergy. Positive APT results may imply that delayed hypersensitivity reactions play a role in children with asthma and rhinitis allergic to HDM.     

Effect of montelukast on exhaled NO in asthmatic children exposed to relevant allergens

The level of exhaled nitric oxide (FENO) is increased in house dust mite (HDM)-sensitized asthmatic children after exposure to HDM antigen, and inhaled steroids can prevent this increase. The aim of this study was to evaluate whether montelukast could prevent an increase in FENO levels in allergic asthmatic children after a brief period of exposure to relevant allergens. Sixteen children were evaluated at the residential house 'Istituto Pio XII' (Misurina, Bellunio, Italy) in the Italian Alps, a dust mite-free environment. FENO levels were evaluated before ( t ₀) and immediately after ( t ₁) the children were exposed to HDM allergens for 2 weeks in their homes at sea level. No significant difference in FENO was observed in the fluticasone-treated group of children after 2 weeks at sea level. In the group treated with montelukast, an increase in FENO was observed between t ₀ and t ₁, which failed to reach statistical significance. These preliminary data suggest that oral montelukast could be effective in preventing the relapse in airway inflammation in allergic asthmatic children who are occasionally exposed to relevant allergens for a short period of time.     

The use of mutually exclusive categories for atopic sensitization: A contrasting effect for family size on house dust mite sensitization compared with ryegrass sensitization

Our aim was to examine the relative importance of family size on sensitization to two different allergens: ryegrass and house dust mite (HDM), using a mutually exclusive classification for allergen-specific sensitization. An 8-year follow-up birth cohort study of children born between 1988–89 was conducted. The follow-up sample consisted of 498 children residing in Northern Tasmania in 1997 (84% of eligible). Outcome measures included skin prick test (SPT) reaction to nine aeroallergens and parental questionnaire. Family size was defined as sibling number in 1997. Children with a positive SPT to either Der p or Der f house dust mite but not ryegrass were classified as HDM-exclusive (n = 84). Children with a positive SPT to ryegrass but not HDM were classified as ryegrass-exclusive (n = 43). Family size was associated with reduced ryegrass-exclusive sensitization [AOR 0.57 (0.39, 0.84) per increase in sibling number] but not HDM-exclusive sensitization [AOR 0.97 (0.77,1.23)]. The difference in the family size effect on these sensitization outcomes was significant (p = 0.02). Similarly, family size tended to be associated with reduced asthma among ryegrass-exclusive sensitized children [AOR 0.45 (0.18,1.12)] but not HDM-exclusive sensitized children [(AOR 1.46(0.80–2.65)]. Large family size was strongly associated with reduced sensitization for ryegrass allergens but not HDM allergens using mutually exclusive sensitization categories. If this difference is confirmed in other studies, the contrasting effect of family size may reflect differences between these allergens with regard to level or timing of early life exposure, differences in allergen -specific potentiation for sensitization or unidentified confounding. The use of mutually exclusive categories for allergen sensitization will assist future work on child atopic disease.     

Childhood asthma and exposure to indoor allergens: lowmite levels are associated with sensitivity

The prevalence and level of sensitivity to indoor allergens were studied in relation to current exposure at home in 124 children with perennial asthma living in three climatic zones of Sweden. The house dust mite (HDM) allergen levels were higher in the South than in the North (p < 0.001), while cat and dog allergen levels tended to be higher in the North than the South (n. s.). Thirty-four percent of the children were sensitive to the HDM Dermatophagoides pteronyssinus , as determined by IgE antibodies in vitro, 27% were sensitive to D. farinae , 57% to cat and 55% to dog. Sensitivity to HDM was significantly more prevalent in Southern, than in Central and Northern Sweden (p=0.001) where the children were more often sensitive to pets (cat p=0.005, dog p= 0.002). A significant association between the concentration of Der p I and Derf I in the house dust and both the prevalence of sensitivity to HDM and the IgE antibody levels against mites was found even at concentrations well below the commonly suggested risk level for sensitisation of 2 μg/g dust. No relationship was found between pet allergen concentration in the home dust and sensitivity to pets, possibly because of exposure outside home, e. g. in schools and meeting places for leisure activities. Similarly, there was no consistent association between the level of mite or pet allergen exposure at home and asthma severity as judged by symptom and medication score. The study indicates that there is no threshold value for sensitisation to mite allergens in asthmatic children, and therefore, dust allergen levels at home should be kept as low as possible in homes of children at risk for asthma.     

Building characteristics affect the risk of allergy development

Damp dwellings increase the risk for house dust mite (HDM) infestation in temperate climate zones and may be associated with an increased risk for allergic disease. The aim of the study was to assess possible relationships between allergen levels in house dust, characteristics of residence buildings and allergic diseases in children. A subsample of 12-yr-old children, having the same address in 1991 and 1996, was selected from a population-based sample of children from the Göteborg area. Health inspectors examined the residences of all the 109 children and several different building characteristics including humidity and indoor temperature were collected. Dust samples for analysis of HDM allergens were collected from the children's beds, and for analysis of cat and dog allergens from the living room. Current health status was assessed by questionnaires, interviews and skin prick tests (SPT). Dog or cat allergens were found in all houses, even in houses without such animals. HDM allergens were found in 60% of the houses, but only six of them had levels exceeding 2 μg/g dust. There was a strong association between HDM-infestation and wheeze, but not with specific sensitization to HDM. The type of building (houses when compared with flats), the ventilation system and the presence of a basement had all major implications on respiratory symptoms, atopy and HDM infestation. We can conclude that dog or cat allergens were found in all houses, and a strong association between HDM infestation and indoor environment. Building construction affected both respiratory morbidity and sensitisation independently, suggesting not only worsening of symptoms but also a causative relationship with disease development.     

Exposure to indoor allergens and development of allergy

House dust contains several indoor allergens which can elicit hypersensitivity and various atopic symptoms, especially in childhood. This review article focusses on house dust mite hypersensitivity to one of the most important species, Dermatophagoides , as a model. A clear dose-response relationship has been demonstrated between house dust mite allergen exposure in mattress dust samples and sensitization, i.e. serum IgE to Dermatophagoides and positive histamine release from basophil leukocytes to one of the major allergens from Dermatophagoides pteronyssinus, Der p I. 2 μg major allergen of Dermatophagoides /g of dust and 8 μg major allergen of cat/g of dust have been suggested to be threshold concentrations above which the risk of sensitization in genetically predisposed atopic children is significantly increased. Epidemiological studies showed house dust mite allergens to be one of the most important risk factors in the development of atopic airway disease. A relation between age at onset of the first wheezing episode and house dust mite allergen exposure at the age of 1 year has been observed. There are various factors influencing house dust mite growth, and many studies have been performed to reduce house dust mite allergen exposure. Until now, none of the approaches appeared to have achieved sufficient mite and mite allergen reduction.     

The effect of high-efficiency and standard vacuum-cleaners on mite, cat and dog allergen levels and clinical progress

The major triggers for allergic asthma are exposure to allergens of the house dust mite, Dermatophagoides pteronyssinus , and of pets. Unfortunately studies of techniques designed to reduce house dust mite and pet allergens have had mixed results. However, new so-called 'improved' products continue to appear on the market and require subjective evaluation. The homes of 60 house dust mite-allergic patients were studied to compare the effects of high-efficiency and standard vacuum-cleaners on allergen concentration. Der p 1 (house dust mite), Fel d 1 (cat) and Can f 1 (dog) allergens were measured in four separate locations in each home. Clinical analysis was by lung function, bronchodilator usage and histamine challenge techniques. There was a significant reduction in Fel d 1 (ng/m²) in dust samples from the living-room carpet (p = 0.046), bedroom carpet (p = 0.003) and mattress (p = 0.013) and living-room sofa (p = 0.005) after 12 months of using the high-efficiency cleaners, but only in the mattress sample using the standard cleaners (p = 0.014). Can f 1 (ng/g dust) was reduced in the mattress sample after using the high-efficiency vacuum-cleaners (p = 0.028), but not at other sites. Der p 1 levels were not significantly changed over this period. Clinically, patients in the high-efficiency group showed improvements in peak expiratory flow rate (PEFR) (p = 0.004), FEV₁ (p = 0.026) and bronchodilator usage (p = 0.005) after 12 months. When the cat-sensitive patients were analyzed separately, improvements in histamine PC₂₀ (p = 0.039) were also seen. Reducing Fel d 1 concentrations, in the absence of any change in Der p 1 concentrations, can produce significant improvements in the lung function of atopic, asthmatic patients. This effect was primarily achieved in those patients with cat sensitivity, but who did not possess a cat themselves.     

House dust mite allergen reduction and allergy at 4 yr: Follow up of the PIAMA-study

Exposure to high allergen levels in early life is a risk factor for the development of allergy. We previously reported limited effects of mite allergen impermeable mattress covers in the prevention and incidence of asthma and mite allergy (PIAMA) cohort at the age of 1 and 2 yr. We now present the results of follow-up at 4 yr objectives. To examine the effects of early reduction of house dust mite (HDM) allergen exposure by means of mattress covers on the incidence of allergy and asthma symptoms in the PIAMA birth cohort at the age of 4 yr. High-risk children (allergic mother) were prenatally recruited and randomly allocated to three groups; receiving mite allergen impermeable mattress covers (n = 416), placebo covers (n = 394) or no intervention (n = 472). At 4 yr of age, atopy was assessed by questionnaire; specific Immunoglobulin E (IgE) to inhalant and food allergens was measured in serum. Dust samples collected from the children's mattresses were analysed for mite allergens. Dermatophagoides farinae1 allergen (Der f 1) levels in dust were reduced in the active group. However, Dermatophagoides pteronissinus 1 (Der p 1) levels, sensitization and atopic symptoms were similar in all groups. We found no effect of mite allergen impermeable mattress covers on sensitization and atopy at 4 yr. Moreover, the allergen reducing effects of the covers had disappeared for one of the two mite allergens that were measured.     

Prenatal exposure to house dust mite allergen (Der p 1), cord blood T cell phenotype and cytokine production and atopic dermatitis during the first year of life

This study investigated the influence of prenatal exposure to house dust mite (HDM, D. pteronyssinus) on interleukin (IL)-2, interferon-gamma (IFN-gamma) and IL-4 producing CD4(+) and CD8(+) T lymphocytes in cord blood as well as on the development of sensitization and occurrence of atopic dermatitis (AD) as the first symptom of allergy during the first year of life. Dust samples (n = 22) were collected by vacuum cleaning the maternal mattress during early to mid-pregnancy. In these samples, the amount of the major HDM antigen (Der p 1) was assessed by a sensitive enzyme-linked immunosorbent assay technique (detection limit 0.004 microg/g dust). Flow cytometry was used to determine cord blood lymphocyte subtypes and to quantify the intracellular amounts of IL-2, IFN-gamma and IL-4 produced by cord blood CD4(+) helper and CD8(+) cytotoxic T lymphocytes, both spontaneously and after stimulation with phorbol-12-mirystate-13-acetate and ionomycin. Children were followed for 1 yr for the presence of symptoms associated with allergy. In addition, at the age of 1 yr specific IgE to different classical inhalant and food allergens was measured. Higher prenatal exposure to Der p 1 (>0.2 microg/g dust) was associated with a significant lower percentage of IFN-gamma producing stimulated CD4(+) T lymphocytes, compared with lower prenatal Der p 1 exposure (p = 0.03). The presence of AD during the first year of life (n = 9) was associated with an increased number of naive CD4(+) CD45RA(+) lymphocytes (p = 0.03), with an increased spontaneous IL-4 production by CD8(+) lymphocytes (p = 0.04) and with a decreased percentage of IFN-gamma producing stimulated CD4(+) lymphocytes (p = 0.04). Furthermore, exposure to HDM during pregnancy tended to be higher in mothers of children with AD during the first year of life when compared with those without AD (p = 0.08). This study shows that the level of prenatal exposure to Der p 1 influences the immune profile of cord blood T lymphocytes and the clinical outcome in early life. Therefore, the prenatal environment must be regarded as a possible early risk factors for allergic diseases in children.     

Placebo-controlled study of the mite allergen-reducing effect of tannic acid plus benzyl benzoate on carpets in homes of children with house dust mite sensitization and asthma

We studied the effect of a spray containing 1% benzyl benzoate, an acaricide, and 1% tannic acid (‘Lowal’; a protein‐denaturing substance), on concentrations of major allergens from house dust mite (HDM) species Dermatophagoides pteronyssinus and D. farinae (Der p 1 and Der f 1, respectively) in carpets. In a double‐blind, placebo‐controlled study with crossover design, 30 homes of children with HDM sensitization and asthma were included. All houses showed ≥ 400 ng/g of Der p 1 + Der f 1 in carpet dust. The first treatment was performed on day 0 (group 1 active treatment, n = 15; group 2 placebo treatment, n = 15). After 2 and 8 weeks, dust samples were collected for quantification of mite allergens. After a 2‐week washout period, the second treatment was performed (group 1 placebo treatment; group 2 active treatment). Again, carpet dust was collected after 2 and 8 weeks. Twenty‐two of 30 families completed the trial: 14/15 in group 1 and eight of 15 in group 2. On day 0, there was no significant difference in mite allergen exposure between group 1 and group 2 (1,498 vs. 2,239 ng/g of Der p 1 + Der f 1, respectively). In group 1, the geometric mean for the difference of mite allergen concentration comparing day 0 and week 6 was 196 ng/g (95% CI: ?7,161 and 8,401) for the first treatment (active) and 15 ng/g (95% CI: ?1,079 and 1,292) for the second treatment (control). In group 2, the difference was 66 ng/g (95% CI: ?398 and 1,515) for the first treatment (control) and 609 ng/g (95% CI: 186 and 9,264) for the second treatment (active). Comparing placebo and active treatment in total, there was a significant decrease following placebo treatment after 14 days (p = 0.026). After 8 weeks, active treatment was superior to placebo treatment (p = 0.049), but the allergen reduction achieved was < 20% (median 1,500 ng/g on day 0 vs. 1,250 ng/g after 8 weeks). We conclude that the slight mite allergen reduction on carpets achieved by the treatment with ‘Lowal’ is unlikely to achieve worthwhile clinical benefit either in the treatment of mite‐sensitive patients or in primary or secondary prophylaxis.     

Comparison between serial skin-prick tests and specific serum immunoglobulin E to mite allergens

Sensitization to dust mite allergens can be determined by means of a skin-prick test (SPT) or by measurement of specific IgE antibodies in serum (sIgE). In our study, concordance of the results of both methods was analyzed on the basis of reproducible SPT results. Three consecutive SPTs were performed on 138 school children (age 6–8 years) at one-year intervals. SIgE was determined at the end of a two-year observation period. Seven common inhalant allergens (Dpt, Df, birch pollens, hazel pollens, grass pollens and cat and dog dander) were analyzed. The majority of subjects with positive SPT reactions to the respective allergen also showed sIgE (Dpt: 82/86; Df: 53/53; cat dander: 31/32; dog dander: 6/9; birch pollens: 29/31; hazel pollens: 22/22; grass pollens: 37/37). A significant correlation between the SPT [weal diameter (P₁) or allergen/histamine ratio (P₂)] and sIgE was found for Dpt (P₁ = 0.004/P₂ = 0.016), birch pollens (P₁ = 0.002/P₂ = 0.0001) and grass pollens (P₁ = 0.0005/P₂ = 0.0001). There was also a significant correlation between sIgE to Dpt and to either Der p 1 (p = 0.0001) or Der p 2 (p = 0.0001), as well as between sIgE of both major allergens (p = 0.0001). In the analysis of co-sensitization of Dpt and Df, most subjects sensitized to Dpt were also sensitized to Df (57/91). Children with sIgE to Dpt (n = 87) usually showed sIgE to Df (n = 83). In this study, SPT and sIgE results are concordant and appear equivalent when using reproducible SPTs. Therefore, in the case of a positive Dpt result, additional testing for sensitization to Df can be regarded as redundant when Dpt and Df are the major contributors to the allergen content of house dust.     

Epidemiology of atopy patch tests with food and inhalant allergens in an unselected population of children

Atopy patch test (APT) has been used as a diagnostic tool in patients with suspected food or inhalant allergy. This study assessed the prevalence of positive APT with food or inhalant allergens in an unselected population of schoolchildren. We also evaluated the link between positive APT reactions and skin‐prick tests (SPT) for food and inhalant allergens, circulating eosinophils and histamine skin reactivity. We studied an unselected population of 380 children aged 9 or 13 yr living in Rome, Italy. APTs were carried out with food (native or standardized) and inhalant allergens. All the children also underwent skin‐prick testing with five common inhalant and four food allergens. We also measured eosinophil cell counts and histamine skin reactivity. The prevalence of positive APT reactions for foods in unselected children ranged between 4% and 11% for hen’s egg, tomato, and wheat flour and was similar for both age groups studied. The prevalence of positive APT for milk was significantly lower in children aged 13 than in children aged 9 (p = 0.013). No concordance emerged between positive APT and SPT for foods. Conversely, APT and SPT for inhalant allergens yielded statistically significant concordance (p < 0.001). APT produces positive reactions for food or inhalant allergens in a significant number of subjects in the general population of schoolchildren. Age influences the prevalence of positive APTs with cow’s milk to some extent. Inhalant allergens probably induce a positive APT reaction through an immunoglobulin E‐linked process, while food allergens probably do not.     

Value of skin prick test and atopy patch test in mite-induced respiratory allergy and/or atopic eczema/dermatitis syndrome

AIM: The atopy patch test (APT) was introduced to assess sensitization to inhalant allergens in patients with atopic/eczema dermatitis syndrome (AEDS), but its diagnostic role in subjects with respiratory allergy is scantly investigated. We sought to evaluate the response to APT and to skin prick tests (SPT) with mite extracts in subjects with persistent respiratory symptoms (rhinoconjunctivitis, rhinosinusitis, asthma), with AEDS, and with both the diseases. METHODS: Eighty-nine patients were included in the study, 75 (84.3%) children and 14 (15.7%) adults, 54 (60.7%) males and 35 (39.3%) females (median age 5.4 years). They were divided in 3 groups, respectively formed by 47 (mean age 12.3+/-11.6 years), 15 (mean age 2.2+/-2.5 years), and 27 (mean age 6.2+/-6.3 years) subjects, according to the presence of only respiratory symptoms, only AEDS, or both, and underwent to usual SPT with mite extracts and to APTs done by mite extract in Finn chambers and removed after 48 hours, with readings after 20 minutes and 24 hours. RESULTS: Of the 89 patients, 24 showed a positive SPT and 69 a positive APT; in 17 both SPT and APT were positive, while 13 were negative to the 2 tests. The APT was more frequently positive than SPT not only in the 2 groups with AEDS -- 32/42 (86.5%) vs 8/42 (21.6%) -- but also in the group with only respiratory symptoms -- 37/47 (78.7%) vs 16/47 (34%). CONCLUSION: These results confirm the high value of APT in patients with mite-induced AEDS and suggest that its routine use might improve also the diagnosis of respiratory allergy to house dust mites.     

Exhaled breath condensate eicosanoids and sputum eosinophils in asthmatic children: A pilot study

Cysteinyl leukotrienes (cys-LTs), LTB₄ and 8-isoprostane are increased in the exhaled breath condensate (EBC) from asthmatic patients. The aim of this study was to investigate whether the measurement of cys-LTs, LTB₄ and 8-isoprostane in EBC can reflect the level of airway inflammation assessed by induced sputum in asthmatic children sensitized to house dust mite (HDM) during natural avoidance of HDM allergens. Twelve children were evaluated at the time of admission (T0) and after 3 months of stay (T1) at the Istituto Pio XII (Misurina, Italian Dolomites 1756  m). Sputum eosinophil percentage and measurement of cys-LTs, LTB₄ and 8-isoprostanes in the breath condensate at T0 and T1 were evaluated. Eosinophil percentage in induced sputum was 8.5 ± 1.1% at T0 and 3.5 ± 0.4% at T1 (p = 0.011). Neutrophil percentage in sputum was 1.1 ± 0.5% at T0 and 1.5 ± 1.0% at T1 (ns). Cys-LTs mean level was 14.24 ± 4.53 pg/ml at T0 and 4.65 ± 0.68 pg/ml at T1 (p = 0.0125). LTB₄ level was 2.36 ± 0.19 pg/ml at T0 and 2.41 ± 0.23 pg/ml at T1 (ns). 8-Isoprostane level reduced from 17.47 ± 3.18 pg/ml at T0 to 7.36 ± 3.26 pg/ml at T1 (p = 0.003). This study show that exhaled cys-LTs and 8-isoprostane, as well as eosinophil percentage in induced sputum, are reduced after allergen avoidance in asthmatic children suggesting a potential application of EBC for the non-invasive evaluation of airway inflammation in asthma in allergic asthmatic children.     

Leukotriene C4 in Children with Atopic Asthma II. Plasma Levels in Bronchial Challenge with Specific Allergen

Peptide leukotrienes C₄, D₄ and E₄ are considered to be major mediators of hypersensitivity reactions. In this study, immunoreactive leukotriene C₄ (iLTC₄) in plasma, taken from asthmatic children who had undergone bronchial challenge with a specific allergen, was measured using radioimmunoassay in order to determine whether LTC₄ is released in duo during human allergic reactions. With regard to the bronchial challenge of 10 asthmatic children, plasma iLTC₄ levels at the postchallenge stage (0.131 ± 0.037 pmol/ml) were significantly elevated compared to the prechallenge stage (0.065 ± 0.016 pmol/ml) (p <0.01). The bronchial response was not directly related to the increased plasma iLTC₄ levels, but the strength of the bronchial response did relate to the plasma iLTC₄ levels at the pre-challenge (p<0.05) and postchallenge (p<0.01) states. The prechallenge levels are relevant to bronchial reactivity, and the post-challenge levels are relevant to bronchocon-striction caused by exposure to allergens. The in vivo release of LTC₄ following exposure to a specific allergen suggests that leukotrienes are important in the pathogenesis of asthma.     

喘息性疾病患儿过敏原检测分析

目的分析喘息性疾病婴幼儿过敏情况,以利早期干预治疗。方法用UniCAP全自动检测仪和皮肤点刺试验对243例喘息性疾病婴幼儿(毛细支气管炎、伴喘息的支气管炎或肺炎、婴幼儿哮喘)进行过敏原筛查和特异性IgE测定。结果1.婴儿期过敏原以食物为主(P=0.03),幼儿期气媒性过敏原阳性率达67.2%;婴幼儿期主要的食物过敏原为牛奶、鸡蛋白;气媒性过敏原是户尘螨。2.进行过敏原特异性IgE测定时,皮肤点刺试验阳性比例低(0～37.5%)。结论婴儿出生后即食入蛋白质,胃肠道功能未健全,易发生食物过敏;幼儿期添加易致敏食物,且在户外时间增多,食物和吸入性过敏均明显。UniCAP系统是一种用于筛查和寻找变应原的较为准确的方法。     

Allergens in urban schools and homes of children with asthma

To cite this article: Permaul P, Hoffman E, Fu C, Sheehan W, Baxi S, Gaffin J, Lane J, Bailey A, King E, Chapman M, Gold D, Phipatanakul W. Allergens in urban schools and homes of children with asthma. Pediatr Allergy Immunol 2012: 23: 543-549. ABSTRACT: Background: Most studies of indoor allergens have focused on the home environment. However, schools may be an important site of allergen exposure for children with asthma. We compared school allergen exposure to home exposure in a cohort of children with asthma. Correlations between settled dust and airborne allergen levels in classrooms were examined. Methods: Settled dust and airborne samples from 12 inner-city schools were analyzed for indoor allergens using multiplex array technology (MARIA). School samples were linked to students with asthma enrolled in the School Inner-City Asthma Study (SICAS). Settled dust samples from students' bedrooms were analyzed similarly. Results: From schools, 229 settled dust and 197 airborne samples were obtained. From homes, 118 settled dust samples were obtained. Linear mixed regression models of log-transformed variables showed significantly higher settled dust levels of mouse, cat and dog allergens in schools than homes (545% higher for Mus m 1, estimated absolute difference 0.55?μg/g, p?相似文献   

Vacuum cleaning decreases the levels of mite allergens in house dust

To investigate the capacity of chemical treatment of surfaces and the difference in capacity among common vacuum cleaners to reduce mite allergen content in house dust, we recruited 52 families with allergic children. Ten families used their central vacuum cleaners. Forty-two families were randomly divided into four groups with 10 or 11 families in each. These families used cither new vacuum cleaners with either HEPA (High Efficiency Paniculate Air) or micro-filters, or their own vacuum cleaners with either tannic acid or placebo. Dust samples were collected from carpets and upholstered furniture in the living rooms and from the mattresses of the children at Days 0, 7, 21, and 35. Der p I and Der f I allergens were determined by sandwich ELJSA, After one week, tannic acid reduced the concentration of mite allergens/g of dust and the total amount/sampling area by 30% and 34%, respectively (p < 0.05), but there was no significant decrease in relation to placebo. After 5 weeks, central, HEPA- and micro-filter vacuum cleaners decreased the mite allergen concentration by 10–50% (p < 0.05) and the total amount of mite allergen from the investigated areas by 50–85% (p < 0.01). In relation to the placebo group the decrease was significant for HEPA-and micro-filter vacuums (p < 0.05), The total amount of mite allergens/ sampling area was more significantly (p < 0.05) reduced than the con-centration/g of dust. We conclude, that tannic acid reduces mite allergen concentrations in dust and total amount/sampling area for a short period of time. Central, HEPA- or micro-filter vacuum cleaners reduce mite ellergen concentrations and still more the total amount of mite allergen in house dust when used regularly for long periods. Therefore, when the total house is thoroughly cleaned, tannic acid should be applied to car pets and upholstery and low mite allergen levels maintained by using modern vacuum cleaners.     

儿童血清过敏原与哮喘发生关系的探讨

目的探讨儿童血清特异性Ig E(s Ig E)过敏原与哮喘发生的关系。方法采用免疫印迹法对2004年12月至2013年4月就诊的2 239例1~14岁单纯哮喘患儿(n=1 415)和非过敏性疾病患儿(n=824)的血清s Ig E过敏原进行检测,分别建立所有样本、不同年龄及不同性别单纯哮喘与非过敏性疾病的病例对照模型,采用多因素logistic回归分析探讨过敏原与哮喘发生的关系。结果 2 239例患儿中,血清s Ig E阳性者1 028例(45.91%),过敏原阳性率居于前三位的为户尘螨(15.68%)、屋尘(14.29%)和霉菌类(13.40%)。病例对照研究结果显示,户尘螨、霉菌类、屋尘、腰果/花生/黄豆是哮喘发病的危险因素(P0.05);不同年龄组与哮喘发生相关的过敏原有所不同,1岁~组儿童仅屋尘与哮喘的发生有关,户尘螨和屋尘是3~14岁儿童哮喘发生的危险因素,而霉菌类是6~14岁儿童哮喘发生的危险因素(P0.05);户尘螨和屋尘是男、女儿童哮喘发生的危险因素(P0.05),而腰果/花生/黄豆和霉菌类仅是男性儿童哮喘发生的危险因素(P0.05)。结论户尘螨、屋尘、霉菌类为哮喘患儿最常见过敏原,且与哮喘发生关系极为密切。     

上海嘉定地区儿童过敏原调查及过敏原与支气管哮喘的相关性

目的：分析上海嘉定地区过敏原及其与支气管哮喘发生的相关性。方法：上海嘉定南翔医院382 例4~12岁缓解期支气管哮喘患儿作为病例组（哮喘组）,采用整群随机法抽取上海嘉定地区2所学校和2所幼儿园402例4~10岁儿童（普查组）作为对照,对儿童家庭生活状况及过敏性疾病患病情况进行问卷调查,并进行18种常见过敏原皮肤点刺试验（SPT）。普查组按出生地分为移居组（219例）和常住组（183例）,分析家庭生活环境与SPT阳性率的相关性。结果：嘉定地区儿童过敏原主要为：粉尘螨、户尘螨、海虾、蟑螂、狗毛。哮喘组SPT阳性率为67.9%,显著高于普查组（31.8%）,二者差异有统计学意义（P＜0.01）。移居组家庭生活环境与常住组有明显差异（P＜0.01）,移居组SPT阳性率明显低于常住组,差异有统计学意义（P＜0.01）。结论：上海嘉定地区儿童主要过敏原为粉尘螨、户尘螨、海虾、蟑螂、狗毛;哮喘儿童对过敏原更具易感性;儿童生活环境与SPT阳性率存在一定相关性。