Seasonal variations in house dust mite allergens--significance for children with allergy

Allergenic proteins of the house dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae and their major allergens Der p I and Der f I are one of the most significant environmental factors which may facilitate sensitization and allergic airway disease in childhood. In order to measure seasonal variations of mite allergen exposure, we collected mattress dust samples monthly in 13 homes over a period of 1 year. Der p I and Der f I were determined with a sandwich type ELISA. Mite allergen levels were significantly lower from January-June than from July-December (p less than 0.05) which was mostly due to Der p I variations. Only in 6 of the studied homes seasonal variations in mite allergen concentrations according to seasonal variations in outdoor humidity could be observed. In 7 homes mite allergen exposure stayed constant and seemed to depend only on indoor climate factors.     

The determinants of dust mite allergen and its relationship to the prevalence of symptoms of asthma in the Asia-Pacific region

The role that house dust mites play in the primary causation of asthma is controversial. Approximately thirty-six 10-yr-old children in each of 10 centres in the Asia-Pacific region participated. Researchers collected dust from mattresses and living room floors using standardized procedures. Der p1 and Der f1 were analysed using a double monoclonal antibody enzyme-linked immunosorbent assay. Geometric mean allergen levels were calculated for each centre. An ecological analysis was conducted to show the regression of the geometric mean allergen level, using the highest household level, against asthma symptom and severity prevalence data from the International Study of Asthma and Allergies in Childhood, Phase I. Among children aged 13–14 yr, the change in asthma symptom prevalence was associated with per unit change in Der p 1  μ g/g (1.08, 95% CI 0.10–2.06) and Der 1  μ g/g (Der p1 + Der f1) (0.64, 95% CI 0.02–1.26). The change in having four or more attacks of asthma in the last 12 months was associated with per unit change in Der p 1  μ g/g (0.29, 95% CI −0.02 to 0.60) and Der 1  μ g/g (0.20, 95% CI 0.01–0.38). There was no effect for total Der p1 or Der f1 (total or μ g/g). Among children aged 6–7 yr, neither allergen was related to symptoms or severity prevalence. While our findings suggest that Dermatophagoides pteronyssinus may have a role in the primary causation of asthma, the complexity of this association reinforces the need for prospective studies.     

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.     

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.     

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.     

Exposure to a high concentration of mite allergen in early infancy is a risk factor for developing atopic dermatitis: A 3-year follow-up study

The cause of allergy is multi-factorial, and the development of an allergic disease seems to be the result of an interaction between genetic and environmental factors. The goal for preventing the development of allergic diseases is to avoid sensitization to allergens. The aim of this work was to study whether or not exposure to environmental allergens early in infancy would influence the occurence of various allergic diseases in later life. On an annual basis, a total of 931 healthy newborns were followed-up until they reached 3 years of age. The occurence of allergic diseases was recorded by trained medical students during visits. Measurement of Dermatophagoides pteronyssinus (Der p 1) concentration in house dust was performed when each baby was 18 and 36 months old. Total and specific immunoglobulin E (IgE) antibodies against Der p 1, cow's milk, and egg white were evaluated at birth and at 18 months of age. The following results were obtained: at 3 years of age, 10.4% had bronchial asthma (BA), 21.4% atopic dermatitis (AD), 7.0% urticaria, and 46.8% had experienced wheezing; higher family allergy scores led to a higher incidence of AD (p=0.0012); exposure to a mite allergen concentration of 1 µg/g of dust may be associated with a higher incidence of AD (p=0.0156); the presence of Der p 1 IgE antibody at 18 months of age was associated with a higher incidence of BA (p=0.0001); and children sensitized to egg whites at 18 months of age had an increased risk of developing AD at 3 years of age (p=0.0187). Hence, early exposure to mite allergen is a risk factor for the development of atopic dermatitis, but seems not to be related to the development of bronchial asthma. Early sensitization to egg whites increases the risk of developing AD. The early detection of serum Der p 1 IgE antibody is associated with a higher incidence of bronchial asthma.     

屋尘螨皮下特异性免疫治疗的哮喘患儿肺功能及免疫学动态变化

目的：动态观察屋尘螨变应原皮下特异性免疫治疗对哮喘患儿的肺功能和免疫学影响。方法：屋尘螨过敏的轻中度哮喘患儿32例,分成治疗组(n=15)和对照组(n=17)。治疗组吸入糖皮质激素的同时加用屋尘螨变应原皮下特异性免疫治疗,对照组仅予吸入糖皮质激素治疗。检测治疗前、治疗后3月、6月、12月、18月、24月肺通气功能,观察治疗前、治疗后12月及24月哮喘发作次数并测定血清总IgE、屋尘螨特异性IgE、屋尘螨特异性IgG4、嗜酸细胞阳离子蛋白（ECP）、IL-10、IL-4及IFN-γ的变化。结果：治疗组患儿治疗后肺通气功能各项参数稳定在正常或接近正常水平;无哮喘急性发作病例的百分率治疗后高于治疗前,随治疗时间的延长而增加（P<0.05）;治疗后屋尘螨特异性IgG4高于治疗前,随着治疗时间延长而增加（P<0.01）;治疗后血清总IgE、屋尘螨特异性IgE、ECP、IL-10、IL-4、IFN-γ水平与治疗前比较,差异无统计学意义。对照组患儿治疗前后各项指标比较,差异均无统计学意义。结论：屋尘螨过敏的轻中度哮喘患儿经屋尘螨变应原皮下特异性免疫治疗2年后,肺通气功能保持正常或接近正常,无哮喘急性发作病例增加,可能与血清屋尘螨特异性IgG4浓度增高有关。［中国当代儿科杂志,2010,12（9）：715-719］     

大鼠发育早期接触变应原对Th1/Th2亚群功能及哮喘发生的影响

目的 探讨妊娠期母鼠及其子代接触尘螨点刺液（Der p）对发育后期个体Th1/Th2平衡及哮喘发生的影响。方法 Wistar大鼠根据母体妊娠期及新生早期是否接触Der p随机分为对照组、母Der p-仔Der p-组（母鼠和其子代均未接触Der p）、母Der p+仔Der p+组（母鼠和其子代均接触Der p）和母Der p+仔Der p-组（母鼠接触Der p,其子代未接触Der p）,分别皮下注射Der p或生理盐水,30 d龄时除对照组外,其余3组以卵白蛋白（OVA）为变应原致敏并雾化吸入,诱发哮喘发生。取血浆检测OVA特异性IgE抗体、收集外周血单个核细胞（PBMC）用ELISA法检测培养上清中细胞因子IL-4和IFN-γ水平,行支气管肺泡灌洗记录支气管肺泡灌洗液（BALF）中嗜酸性粒细胞的计数,留取肺组织行病理学检查。结果 母Der p+仔Der p+组在哮喘建模后PBMC培养上清中IFN γ水平显著低于母Der p-仔Der p-组,IL-4水平显著升高,IL-4/IFN-γ比值升高,OVA特异性IgE、BALF中嗜酸性粒细胞计数显著高于母Der p-仔Der p-组;母Der p+仔Der p-组与母Der p-仔Der p-组IL-4和IFN-γ水平差异均无统计学意义,OVA特异性IgE水平虽有增高,但差异不具统计学意义,BALF中嗜酸性粒细胞计数差异无统计学意义。母Der p+仔Der p+组Th2优势显著高于母Der p+仔Der p-组。 结论 胎鼠对于Der p跨胎盘的致敏作用可通过母体妊娠期间的免疫来完成,这一过程会根本上导致Th2优势免疫的发生,增加了变态反应性疾病的危险性。     

Risk factors, clinical and laboratory aspects of asthma in children

OBJECTIVE: To evaluate the clinical and laboratory aspects and the risk factors associated with asthma in children treated at the Pediatric Outpatient Clinic of Hospital Universitário Júlio Müller. METHODS: A case-control study including 59 asthmatic children (cases) and 104 nonasthmatic children (controls). The following factors were considered for risk analysis: parent? level of education, domestic exposure to allergens, passive smoking, breast feeding, low income, and family history of allergy. Samples of blood were collected for hemogram and to determine the total serum IgE as well as the one specific to allergens. Immediate hypersensitivity skin tests were performed with puncture for the detection of the following allergens: house dust mite, animals, molds, and cockroaches with positive (histamine) and negative controls (physiologic solution). A logistic regression model was used to calculate the odds ratio (OR) and 95% confidence intervals (95%CI) adjusted for risk factors and for confounding factors. RESULTS: Among the risk factors studied, sex, parent? low level of education, low income, length of the breast feeding period, and passive smoking were not associated with the presence of asthma. The domestic exposure to allergens was similar in both groups except for the higher frequency of pets at the homes of control patients (chi-square=16.9; P<0.05). Paternal history of rhinitis was the only association with asthma (OR=3.33; 95%CI: 1.03-11.17; P<0.05). The asthmatic children presented higher frequency of positive reactions to skin tests than the controls, mainly to house dust mites: Dermatophagoides pteronyssinus (69.5%), Dermatophagoides farinae (59.3%) and Blomia tropicalis (59.3%); cockroaches: Periplaneta americana (59.3%), and cat: Felis domesticus (37.3%), with OR between 11.2-21.0; P<0.05. Eosinophilia and serum levels of total IgE were more elevated in the group of asthmatic children (P<0.05). The positivity of the specific IgE test for Dermatophagoides pteronyssinus and Blomia tropicalis was higher in the cases than in the controls (P<0.05). The multivariate analysis showed that sensitization to the allergens produced by cockroaches (OR=9.26; 95%CI: 2.59-33.4), animals (OR=3.93; 95%CI: 1.05-14.67) and house dust mites (OR=3.74; 95%CI: 1.18-11.8) were the most important risk factors for asthma. CONCLUSIONS: The sensitization to indoor allergens, mainly to house dust mites, cockroaches, and cats showed a strong association with asthma in this study.     

Low frequency of positive skin tests in asthmatic patients infected with Schistosoma mansoni exposed to high levels of mite allergens

Helminthic infections and allergic diseases are highly prevalent in many parts of the world. Although skin reactivity to indoor allergens is decreased in subjects from helminthic endemic areas, the degree of exposure to mite allergens has not yet been investigated in these areas. This study evaluated the association between exposure to dust mites and skin reactivity to mite allergens in subjects with a history of wheezing in the last 12 months selected from a rural endemic area for schistosomiasis (group I, n = 21), and two non- Schistosoma mansoni endemic locale, a rural area (group II, n = 21) and a urban slum area (group III, n = 21). All subjects were evaluated by skin prick tests with mite allergens, and for total and specific immunoglobulin E (IgE) against dust mites, antibodies for S. mansoni , and for intestinal parasites. Dust samples from each subjects' home were quantified for mite allergen and species of the mite identification. Except for S. mansoni infection which was more prevalent in group I than in groups II and III (p < 0.0001), the prevalence of intestinal parasites, and total and specific IgE levels were similar for all groups. Despite the levels of mite allergens and specifically to Der p 1 detected in dust samples of subjects home from all three areas, the frequency of positive skin reactivity to mite antigens was significantly lower (19.0%) in subjects from group I relative to group II (76.2%) and group III (57.1%; p < 0.001). This result suggests that S. mansoni infection could modulate the immediate hypersensitivity skin response to mite allergens in highly exposed subjects.     

Effects of an acaricide on mite allergen levels in the homes of asthmatic children

Previous study by the current authors has shown that treating homes with D'Allergen, an acaricidal agent, can reduce bronchial hyper-reactivity in asthmatic children with house dust mite allergy. In the present study, the effects of a single D'Allergen treatment on the levels of major dust mite allergens, Der p I and Der f I was evaluated, and the duration of its effectiveness in the environment determined. Twenty randomly selected homes were treated with the acaricide and ten remained untreated. Dust samples were collected from mattresses, upholstered sofas and carpets of these homes before and 1, 2 and 4 months after treatment. The samples were then assayed for Der p I and Der f I allergens using a sandwich enzyme immunoassay. The results showed that D'Allergen was effective in reducing dust mite allergen levels in all three niches by 1.5–22.3 times below baseline values. This effect, however, was only present for 2 months, and the dust mite allergen levels increased to those of the baseline by the fourth month after treatment. These results indicated that repeated applications of the acaricide were required at 2–3 monthly intervals to obtain optimal effectiveness.     

Concentrations of cat (Fel d 1), dog (Can f 1) and mite (Der f 1 and Der p 1) allergens in the clothing and school environment of Swedish schoolchildren with and without pets at home

To investigate whether our hypothesis that cat and dog owners bring allergens to public areas in their clothes was true or not, we studied the levels of Fel d 1, Can f 1, Der p 1 and Der f 1 in dust from the clothes and classrooms of children in a Swedish school. We also investigated the levels of allergen in different areas in the four classrooms used by the children. Thirty-one children were selected in four classes, forming three groups: cat owners, dog owners and children without a cat or dog at home. Furthermore, a group of children with asthma was included. Cat and dog allergens were detected in all 57 samples from clothes and classrooms. Mite allergen Der f 1 was detected in low concentrations in 6 out of 48 and Der p 1 in 5 out of 46 samples investigated. The concentrations of Can f 1 were higher than those of Fel d 1 in samples from clothes (geometric mean: 2676 ng/g fine dust and 444 ng/g) and classrooms (Can f 1: 1092 ng/g, Fel d 1: 240 ng/g). The dog owners had significantly higher concentrations of Can f 1 (8434 ng/g fine dust) in their clothes than cat owners (1629 ng/g, p <0.01), children without cat or dog (2742 ng/g, p < 0.05) and children with asthma (1518 ng/g, p < 0.001). The cat owners did not have significantly higher levels of Fel d 1 (1105 ng/g) in their clothes compared to the other three groups (D: 247 ng/g, nCnD: 418 ng/g, A: 386 ng/g) but the levels were significantly higher than for all children without a cat at home (345 ng/g, p < 0.05). No concentrations of mite allergen and low concentrations of Fel d 1 and Can f 1 were found in the children's hair. There were significantly higher concentrations of Fel d 1 and Can f 1 in dust from curtains than in samples from floors and bookshelves (p < 0.05). There was no significant difference between the allergen concentrations in samples from curtains and from desks and chairs, including the teachers' chairs, the only upholstered furniture in the rooms. Our results support the hypothesis that cat and dog owners bring allergens to public areas in their clothes and support other studies showing that textiles and upholstered furniture function as reservoirs of cat and dog allergens. Thus, children with asthma and other allergic diseases will be exposed to cat and dog allergens at school and by contact with pet owners, even if they avoid animal allergens at home.     

Individual time-courses of ECP and EPX during allergen provocation tests in asthmatic children

To study the time-course of eosinophil cationic protein (ECP) and eosinophil protein X (EPX) during bronchial allergen provocation, we investigated 32 asthmatic children sensitive to house-dust mites as well as 6 non-atopic young adult controls. In all subjects, allergen challenges were performed with house dust mite extracts of Dermatophagoides pteronys-sinus or Dermatophagoides farinae. Blood samples were taken at regular intervals during the 24-h observation period. The individual time-courses of ECP and EPX revealed different characteristic groups of patterns: (1) an isolated early serum peak of both mediators during or within the first 60 min after provocation (2) an early plus a late peak (3) an isolated late peak 12 h after provocation (4) an isolated late peak 24 h after provocation, and (5) no significant variation during the 24-h observation period. The early peak could be due to short-term changes in eosinophil activation, while late peaks may reflect eosinophil proliferation, recruitment, subsequent priming and enhancing of the propensity to release their proteins. ECP and EPX showed a corresponding parallel time-course in nearly all challenges, with EPX-concentration exceeding that of ECP. There was no correlation between ECP/EPX serum concentrations and clinical parameters such as lung function data. From our results we conclude that the striking groups of time-courses of ECP/EPX serum concentration indicate different uniform patterns of eosinophil activation during allergen challenge - but do not predict clinical outcome of provocation. The role of the eosinophil in early asthmatic reactions remains to be established in further studies.     

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目的比较3~14岁哮喘和变应性鼻炎患儿吸入性致敏原分布特征的异同。方法2004-10—2005-10,北京儿童医院对527例哮喘和620例变应性鼻炎患儿进行吸入性致敏原皮肤点刺试验(skin prick test,SPT),分析比较检出阳性的致敏原在两组病例中的分布特征。结果哮喘和变应性鼻炎患儿SPT阳性检出率分别为77·8%和78·9%(χ2=0·823,P>0·05)。户尘螨、粉尘螨、交链孢霉、猫上皮、艾蒿是两种疾病主要致敏原。哮喘患儿户尘螨、粉尘螨、混合霉菌的阳性率分别为64·6%、59·8%、8·8%,均高于变应性鼻炎患儿(49·5%、47·9%、3·9%,均P<0·05)。变应性鼻炎患儿杂草花粉和艾蒿的阳性率分别为25·6%、26·0%,均高于哮喘患儿(19·3%、19·3%,均P<0·05)。40·2%的哮喘和46·2%的变应性鼻炎为单致敏原阳性。尘螨霉菌混合致敏及尘螨宠物混合致敏在哮喘和变应性鼻炎中最为常见。结论尘螨、霉菌、夏秋季花粉和宠物是3~14岁哮喘和变应性鼻炎患儿主要吸入性致敏原,两病具有相似的致敏原分布特征,但尘螨及霉菌过敏多见于哮喘,夏秋季花粉过敏多见于变应性鼻炎。     

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.     

Frequency of sensitization to D. pteronyssinus or D. farinae in children with perennial bronchial asthma

Bronchial sensitization against house dust mites (dermatophagoides farinae, dermatophagoides pteronyssinus) was investigated in 48 children. The therapeutic effect of hyposensitization and removal of house dust mite allergen was evaluated. The diagnosis was established by skin-prick-test, RAST and bronchial provocation. The bronchial provocation test was carried out by a whole body plethysmograph with breath by breath registration of the airway resistance. We found a bronchial reaction against both mites in 70% of the children; 18% showed bronchial reaction only against d. farinae, 10% only against d. pteronyssinus. There was a better correlation between RAST and bronchial provocation (69,5%) than between skin-prick-test and bronchial provocation (65%). The correlation concerning the skin-brick-test and RAST was 55% with d. farinae and 59% with d. pteronyssinus. There was no correlation between PRIST and RAST, RAST and eosinophiles, therapeutic effects of hyposensitization and positive allergen tests. After one year of therapy, the conditions of 87,5% (only mite sensitization) respectively 92% (mixed sensitization) of patients improved. Another group of sensitized children was only treated by removal of house dust mite allergen and anti-allergic and bronchodilating drugs. 43% (mixed allergy) respectively 54% (only mite sensitization) had less asthma problems. After the hyposensitization the children showed a significant improvement. There was no difference in the therapeutic effect after hyposensitization against d. farinae or d. pteronyssinus.     

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.     

标准化屋尘螨变应原特异性免疫治疗对儿童变应性鼻炎合并哮喘的临床疗效

目的 评估标准化屋尘螨变应原特异性免疫治疗(specific immunotherapy,SIT)对儿童变应性鼻炎合并哮喘的临床疗效.方法 选择我院42例接受标准化屋尘螨SIT的变应性鼻炎合并哮喘儿童为研究对象.所有患儿治疗前、治疗1年后均进行变应原皮肤点刺试验、测定血清屋尘螨和粉尘螨特异性IgE水平、进行肺功能测定和自觉症状评分.结果 治疗1年后屋尘螨和粉尘螨的皮肤指数和自觉症状评分均较治疗前显著降低(P＜0.01,P＜0.05),而治疗前后屋尘螨和粉尘螨特异性IgE水平、肺功能(肺活量、第1秒用力呼气量、最大呼气中段流量)均无明显变化(P＞0.05).结论 变应性鼻炎合并哮喘儿童给予SIT1年后其皮肤敏感性显著改善,临床症状明显好转,但对气道炎症的影响有待于进一步的观察.     

Clinical and immunologic effects of sublingual immunotherapy in asthmatic children sensitized to mites: a double-blind, randomized, placebo-controlled study

Immunotherapy through oral routes is thought to be a valuable therapeutic option for asthma. The clinical and immunologic effects of sublingual immunotherapy (SLIT) in children with asthma caused by mites were evaluated in a double-blind, placebo-controlled study for 6 months. Patients (aged 6-12 yr) with mild-to-moderate asthma, with single sensitization to mite allergen, received either SLIT or placebo with a standardized Dermatophagoides pteronyssinus (D.p.)/D. farinae (D.f.) 50/50 extract. The cumulative dose was around 41824 IR, equivalent to 1.7 mg of D.p. and 3.0 mg of D.f. allergen. Symptom and medication scores were assessed throughout the study. Serum total immunoglobulin (Ig)E, eosinophil count, eosinophil cationic protein, specific IgE, specific IgG4, and skin sensitivity were evaluated before starting the treatment and after the treatment period. Twenty patients completed the study. At the beginning of the treatment, no differences were observed between the groups for symptom and medication scores, skin sensitivity, or immunologic parameters. After 6 months of treatment, there was a significant difference in nighttime asthma symptom scores and specific IgG4 (p < 0.05) in the SLIT group compared with the placebo group. Daytime symptom and medication scores, total IgE, eosinophil count, forced expiratory volume in 1 s, and mean evening peak expiratory flow rate reached significant differences in the SLIT group during the treatment period (p < 0.05). No severe adverse effects were reported. Our results revealed that treatment for 6 months with SLIT is clinically effective in decreasing asthmatic symptoms and medication use in children with mild-to-moderate asthma because of mite sensitivity. The clinical usefulness of this form of immunotherapy and the mechanism underlying its immunologic effects deserve further studies.     

908例哮喘儿童皮肤点刺试验分析

目的：分析哮喘儿童皮肤点刺试验结果,探讨皮肤点刺试验的临床应用及理论价值。 方法：使用丹麦爱尔开-阿贝优公司的吸入组点刺试剂和德国默克公司生产的阿罗格食入组点刺试剂进行皮肤点刺试验,组胺液为阳性对照,生理盐水为阴性对照。结果：①908例哮喘儿童皮肤点刺试验阳性率为77.4%。吸入变应原总阳性率76.9%,吸入变应原中以粉尘螨和屋尘螨阳性率居高,分别为72.4%和74.7%;食入变应原总阳性率37.1%,食入变应原在前3位的为小虾22.9%,金枪鱼7.3%,蚌6.7%。②皮肤点刺结果为强阳性（++++）的以粉尘螨和屋尘螨为主,分别为64.0%和66.4%,其次为霉菌1,阳性率为7.1%。③1～14岁哮喘儿童吸入变应原与食入变应原阳性率随年龄增加均有升高趋势,在各年龄分组中吸入变应原与食入变应原各年龄组两两比较差异均有显著性意义（P<0.05）。结论：908例哮喘儿童皮肤点刺试验有较高的变应原检出率,对哮喘的流行病学调查及特异性免疫治疗均有一定的指导意义。［中国当代儿科杂志,2009,11（7）：559-561］