Hen's egg allergen in house and bed dust is significantly increased after hen's egg consumption—A pilot study

Environmental exposure to food allergens may be a risk factor for cutaneous sensitization. Previous studies could detect peanut allergen in house dust. In this pilot study, we wanted to investigate whether hen's egg allergen is detectable in house dust collected from different household areas and whether levels are increased after intentional hen's egg consumption. Hen's egg protein levels of dust samples were measured using ELISA. In 8 of 8 households, hen's egg was detectable in dust samples of eating area and bed. Forty‐eight hours after intentional hen's egg consumption, hen's egg protein levels were significantly increased in both. Still, further research is necessary to investigate whether hen's egg allergen in house and bed dust plays a role in sensitization via skin.     

Immunochemical quantification of the airborne mite allergens

We collected airborne particle from indoor air by using a high-volume air sampler, and measured mite allergens in the air-filter extract by use of RAST inhibition assay. The results obtained were as follows: 1) The assay revealed the presence of house dust mite allergen in the indoor air varying from 690 to 129000 pg/m3. 2) In apartments, seasonal fluctuations of house dust mite allergen in the indoor air demonstrated a peak in autumn (September and October), and showed a tendency to increase in spring. In our outpatient clinic, the quantity of house dust mite allergen in the indoor air varied from 690 to 5670 pg/m3, while there were few mites on the floor, and showed a tendency to increase in winter. 3) There was a significant correlation between the quantity of house dust mite allergen in the indoor air and the number of mite in house dust (r = 0.535, p less than 0.01). 4) The amount of D.f. allergen in the indoor air was significantly decreased by using air cleaners (p less than 0.005). These results showed that the quantification of house dust mite allergen was useful from the clinical point of view as a parameter of mite pollution indoors, and it was important for asthmatics to live in clean environment, and to decrease the number of mites in house dust.     

Possible indirect binding of IgE in house dust RAST.

House dust subfractions obtained in the course of purification exhibit increasing skin reactivity in allergic patients, which runs parrallel to both complement-consuming and RAST-binding capacity. Working with highly purified house dust allergen in RAST, the correlation with clinical parameters for house dust allergy was found to remain poor. In a large group of sera a significant statistical correlation was found between total IgE and allergen-binding IgE. Ultracentrifugation experiments demonstrated that IgE binding to allergen in RAST occurs in complex with an unidentified serum protein. These results suggests that IgE binding in house dust RAST is indirect and is mediated by another serum factor.     

Sensitization to house dust mites in Reykjavik, Iceland, in the absence of domestic exposure to mites

BACKGROUND: House dust mites are common sources of indoor allergens. In Reykjavik, Iceland, 9% of the young adult population had serum-specific IgE to Dermatophagoides pteronyssinus. Sensitization to mites is usually assumed to be due to exposure to house dust mites in the indoor environment. This investigation was carried out to measure the concentrations of house dust mite allergens and to investigate which species of mites were present in beds in Iceland. METHODS: A total of 197 randomly selected adults were visited at home using the European Community Respiratory Health Survey (ECRHS) II Indoor protocol. Dust samples were collected from mattresses for measurement of house dust mite allergen concentrations and to estimate the number and type of house dust mites. Additional samples from mattresses and floors were collected from the homes of 10 patients with positive skin prick tests (SPT) to D. pteronyssinus. House dust mite allergen concentrations were measured using ELISA and examination of mite species was carried out using microscopy. Climatic parameters were assessed using psychrometer readings in the bedrooms and outdoors. RESULTS: We found two single mite specimens, both D. pteronyssinus, in two dust samples. Mite allergen analyses indicated that two other dust samples had Der f 1 results close to the cut-off of 0.1 microg/g of dust. No samples were positive for Der p 1. In an additional collection of dust from the homes of 10 SPT-positive patients no Dermatophagoides spp. were found. CONCLUSIONS: Reykjavik citizens are exposed to extremely low amounts of house dust mite allergens in their homes. Possible alternative sources for sensitization are discussed, such as bird nests, exposure from travelling abroad, or other mites or invertebrates that cross-react with house dust mite allergens. Our findings suggest that exposures other than to house dust mites indoors are possible sources of mite allergen exposure.     

Molecular characterisation of group I allergen Eur m I from house dust mite Euroglyphus maynei.

Using the polymerase chain reaction (PCR) we have amplified and cloned genomic DNA encoding the secreted group I allergen proteins from the house dust mite species Euroglyphus maynei, Dermatophagoides pteronyssinus and D. farinae. Affinity chromatography using a monoclonal antibody to the allergen Der p I was used to purify the group I protein from E. maynei. We present the deduced amino acid sequence of a new member of the group I house dust mite allergen family Eur m I. The three proteins show a high level of primary structure similarity: Eur m I and Der p I show 85% amino acid identity, and the three allergen amino acid sequences taken together show 78% identity. A potential N-glycosylation site and residues of the cysteine protease active site are also conserved between the three proteins.     

Photo-inactivated allergens

Purified house dust allergen irradiated with UV-light loses its capacity to elicit immediate type skin and bronchial provocation reactions in the majority of asthmatic patients. However, in some patients both immediate and/or late bronchial reactions were observed to the active house dust and its inactivated counterpart. Immunotherapy with UV-irradiated house dust allergen, which hyposensitized 66% of forty-eight asthmatic patients allergic to house dust, was as effective as treatment with aluminium oxide-adsorbed active house dust, and there were fewer adverse side-effects.     

Comparison of allergen-induced late inflammatory reactions in the nose and in the skin in house dust mite-allergic patients with or without asthma

BACKGROUND: It remains to be established which factors contribute to the occurrence of asthma in allergic individuals. We hypothesized that differences in the late allergic inflammatory reaction to allergen between asthmatic and non-asthmatic house dust mite-allergic individuals might contribute to the difference in the clinical presentation of allergy. AIM: To compare allergen-induced changes in parameters for cellular inflammation during the phase of the late allergic reaction in the skin and nose, in house dust mite-allergic individuals with or without asthma. MATERIAL AND METHODS: Nasal and dermal allergen challenges with house dust mite (Dermatophagoides pteronyssinus) extract were performed in 52 house dust mite-allergic individuals, of whom 26 had mild to moderate persistent asthma and 26 had perennial rhinitis without current or past asthmatic symptoms. Serial nasal lavage samples were analyzed for the presence of inflammatory cells (eosinophils and neutrophils) and soluble markers associated with cellular inflammation [interleukin-5 (IL-5), interleukin-8 (IL-8), eosinophil cationic protein (ECP) and myeloperoxidase (MPO)]. Macroscopic late phase skin reactions were studied after intracutaneous skin tests with house dust mite extract. RESULTS: Fixed dose nasal allergen provocation elicited a similar degree of immediate allergic reaction as judged by plasma protein exudation and histamine concentrations in asthma and non-asthmatic rhinitis. Subsequently, no differences between groups were found during the phase of the late allergic reaction (4-24 h) in inflammatory cell influx, plasma protein leakage, ECP or MPO. Likewise, there were no differences in levels of chemotactic cytokines IL-5 and IL-8. In agreement with the results of nasal challenge, the late skin reaction after dermal challenge with a fixed allergen dose and after an allergen dose 10,000 times above the skin threshold for an early skin reaction did not differ between the groups. CONCLUSION: House dust mite-allergic patients with or without asthma have very similar late allergic inflammatory reactions in the skin and in the nose after allergen challenge. Hence, it is unlikely that the occurrence of pulmonary symptoms in asthma is explained by a general tendency of asthmatics to have an enhanced late allergic cellular inflammatory response. Nasal and dermal allergen provocations are adequate models to study allergen-induced inflammation but probably lack the pivotal link which is essential for the development of asthma.     

Allergen- and anti-IgE-induced histamine release from whole blood

The release of histamine by allergen and anti-IgE from whole blood was observed in 34 asthmatic subjects with a positive skin test to house dust. The time course of histamine release showed that the release by allergen and anti-IgE peaked after 15 min incubation. There was no significant difference in the time course of the release from whole blood between allergen and anti-IgE. Anti-IgE-induced histamine release correlated to a certain extent with the serum IgE level. Histamine release by house dust, on the other hand, correlated with the radioallergosorbent test score. A striking difference was present in the dose-response slope between allergen and anti-IgE. The maximum percent release correlated with the dose-response slope by allergen, but not by anti-IgE. The amount of histamine release induced by anti-IgE paralleled the amount of the release by house dust in the cases sensitive to the allergen; less sensitive basophils to anti-IgE were less sensitive to house dust.     

T cell cytokine responses to outer membrane proteins of Haemophilus influenzae and the house dust mite allergens Der p 1 in allergic and non-allergic subjects

BACKGROUND: Haemophilus influenzae are ubiquitous colonizers of the nasopharynx, Little is known about the T cell cytokine responses to the antigens of these bacteria and whether or not the responses may interact with responses to aeroallergen. OBJECTIVE: To measure the T cell cytokine responses to conserved outer membrane protein antigens of Haemophilus influenzae and to house dust mite allergen of subjects allergic to the house dust mite and of subjects without allergic sensitization. METHODS: T cell responses were measured by in vitro proliferation and cytokine release from peripheral blood monocytes (PBMC). The allergen used was Der p 1 and outer membrane proteins were recombinant polypeptides representing the OMP6 and D15 antigens. RESULTS: The PBMC of most subjects had proliferative responses to OMP6 and D15, which were highly correlated. The pattern of cytokine release was Th1 biased with high levels of IFN-gamma and usually little IL-5 or IL-13 although PBMC from a few subjects did release IL-5 independent of allergic status. IL-10 release was readily detected. There was no difference in the anti-OMP cytokine response of PBMC from subjects without any known allergy and the responses of PBMC from subjects who were highly allergic to house dust mite. The responses to the Der p 1 allergen showed the expected Th2 cytokine release. CONCLUSION: The outer membrane protein antigens of the ubiquitous colonizing bacteria Haemophilus influenzae induce Th1 cytokine responses which are similar for PBMC from non-allergic individuals and subjects with a high degree of allergy to the perennial house dust mite allergen and strong Th2 responses to Der p 1.     

House dust mite allergen in US beds: results from the First National Survey of Lead and Allergens in Housing

BACKGROUND: Although exposure to house dust mite allergen is a major risk factor for allergic sensitization and asthma, nationwide estimates of dust mite allergen levels in US homes have not been reported. OBJECTIVE: The purpose of this study was to estimate the prevalence of dust mite allergen in beds of US homes and to identify predictors of dust mite allergen concentration. METHODS: Data were obtained from the first National Survey of Lead and Allergens in Housing, a cross-sectional survey of 831 permanently occupied noninstitutional housing units that permitted resident children. Dust mite allergen concentration (Der f 1 plus Der p 1) was determined from a dust sample collected from a bed. The percentages of homes with concentrations at or greater than detection, 2.0 microg/g bed dust, and 10.0 microg/g bed dust were estimated. Independent predictors of allergen concentration were assessed with multivariable linear regression. RESULTS: The percentages of US homes with dust mite allergen concentrations at or greater than detection, 2.0 microg/g, and 10.0 microg/g were 84.2% (SE, 1.73), 46.2% (SE, 2.0), and 24.2% (SE, 2.1), respectively. Independent predictors of higher levels were older homes, non-West census regions, single-family homes, no resident children, lower household income, heating sources other than forced air, musty or mildew odor, and higher bedroom humidity. CONCLUSION: Most US homes have detectable levels of dust mite allergen in a bed. Levels previously associated with allergic sensitization and asthma are common in US bedrooms. Predictors can be used to identify conditions under which homes are more likely to have increased dust mite allergen levels.     

Non-allergenic antigen in allergic sensitization: responses to the mite ferritin heavy chain antigen by allergic and non-allergic subjects

BACKGROUND: The majority of house dust mite proteins are non-allergenic. There is, however, no information on the type of immune responses produced to these proteins and if the responses are affected by allergic sensitization. OBJECTIVE: To identify and produce a non-allergenic antigen of the house dust mite and compare antibody and T cell responses with the responses to allergens in sensitized and non-sensitized individuals. RESULTS: Ferritin heavy chain was cloned from a cDNA library as a candidate non-allergen of the house dust mite. It bound IgG but not IgE in the sera of allergic and non-allergic subjects and induced high T cell proliferative responses that correlated highly with the responses to the major allergen Der p 2. The cytokine response to the non-allergen was characterized by the release of high levels of both Th1 and Th2 cytokines from the PBMC of both allergic and non-allergic subjects. In contrast, the response to Der p 2 showed the expected high level of Th2 cytokine release from the PBMC of allergic subjects, while the Th2 cytokine production from PBMC of non-allergic subjects was low and even lower than that induced by ferritin heavy chain. The levels of IFN-gamma release were similar for all groups. Der p 2 induced significantly more IL-10 than ferritin in the non-allergic group. CONCLUSION: The T cell responses to a non-allergenic protein of the house dust mite were high and strongly correlated with the response to the major allergen. The non-allergenic protein induced high levels of Th1 and Th2 cytokine in both allergic and non-allergic subjects, while the allergen induced high levels of Th2 cytokine in allergic subjects and low levels in non-allergic subjects. The responses to the allergen were thus independently up- and down-regulated with no evidence of bystander regulation.     

过敏原蛋白组分sIgE检测及分析

目的 分析过敏性疾病患者血清中多种过敏原蛋白组分的sIgE,明确过敏原中的致敏蛋白组分,为临床过敏性疾病预防和治疗提供科学依据.方法 采用荧光酶联免疫法,用ImmunoCAP过敏原检测试剂检测受试者血液标本中过敏原蛋白组分及相关过敏原的特异性IgE(sIgE)水平,统计每种过敏原蛋白组分sIgE检出量和阳性率,并对主要致敏蛋白组分sIgE阳性率和相关过敏原的阳性率进行对比和分析.结果 40种过敏原蛋白组分的阳性率均小于过敏原的阳性率,致敏组分和交叉过敏组分共存于过敏原中.户尘螨、黄胡蜂毒、桃、猫毛、榛子、牛奶和鸡蛋的主要致敏蛋白组分阳性率高于过敏原阳性率的50%;百慕达草、意大利蜜蜂毒、桦树和花生的主要致敏蛋白组分阳性率介于过敏原阳性率的20%~50%之间;虾、狗毛、梯牧草和北艾草的主要致敏蛋白组分阳性率低于过敏原阳性率的20%.结论 过敏原蛋白组分检测能鉴别过敏原中真正致敏的蛋白组分,解决由于交叉反应所导致的过敏原特异性诊断难题,确保过敏性疾病特异性免疫治疗的精确性和有效性.     

The isolation of an allergen from extracts of Dermatophagoides pteronyssinus using a murine IgA myeloma with a specificity for phosphorylcholine

The presence of a high molecular weight glycoprotein component bearing the hapten phosphorylcholine (Pc) has been demonstrated in some but not all extracts of house dust mite using a phosphorylcholine specific IgA myeloma protein (S107). The Pc bearing component was isolated from house dust mite extracts by precipitation at equivalence using whole myeloma serum and the isolated fraction was found to be allergenic as judged by a direct RAST assay using a highly house dust mite allergic human serum pool. RAST inhibition studies using free hapten and direct RAST studies using pneumococcal polysaccharide C-substance indicated that the Pe moiety did not contribute significantly to the immunodominant portion of the isolated allergen. Further studies indicated that the S107 isolated material was immunochemically different from the tridacnin reactive material and the con A reactive material previously isolated from extracts of house dust mite.     

Cat allergen content of commercial house dust extracts: Comparison with dust extracts from cat-containing environment

Eighteen lots of house dust extract from nine commercial sources (obtained as weight per volume or protein nitrogen unit per cubic centimeter) were analyzed for cat allergen content by direct quantitative immunoelectrophoresis after concentration. Cat allergen 1 was measurable (greater than 0.3 units) in 11 extracts with a mean (range) of 5.8 (1.3 to 31.0) U/gm of source material. Cat albumin was measurable (greater than 2.4 units) in 12 extracts with a mean (range) of 53.4 (11.5 to 319.7) U/gm. In order to evaluate whether the cat allergen 1 content is a significant contribution to the allergenic activity of the extract, 17 cat-allergic subjects were tested by prick test with a purified preparation of cat allergen 1. The mean (range) concentration that produced a 3 mm wheal was 0.01 (0.0013 to 1.33) U/ml. Therefore, the commercial house dust extracts studied, when these extracts were diluted to a concentration commonly used for prick testing, would frequently contain enough cat allergen 1 to produce strong prick test reactions in cat-allergic subjects. It is difficult to justify the use of such commercial dust extracts as diagnostic reagents. For comparison purposes, nine dust samples from an apartment housing two cats were similarly analyzed. Cat allergen 1 was measurable in seven samples with a mean (range) of 23.8 (1.8 to 64.3) U/gm. Cat albumin could be measured in all nine samples with a mean (range) of 32.3 (0.16 to 70.8) U/gm. The average amount of cat allergen 1 that could be washed off the surface of the cats was 270 units. Large reservoirs of cat allergen 1 were present.(ABSTRACT TRUNCATED AT 250 WORDS)     

Monoclonal antibodies to recombinant Der f 2 and development of a two-site ELISA sensitive to major Der f 2 isoallergen in Korea

BACKGROUND: Der f 2 is a major sensitizing allergen in patients allergic to house dust mites worldwide. Isoforms of Der f 2 have been reported and are known to have different antigenicities. The aim of this study was to facilitate antigenic analysis and to develop an improved method for the detection of Der f 2 isoallergen, which is prevalent in Korea. METHODS: A two-site ELISA was developed with monoclonal antibodies (mAbs) which were produced against recombinant Der f 2 (rDer f 2) and applied to assess Der f 2 in bedding samples. RESULTS: A major isoform of Der f 2, found in Korea, was found to have amino acid variations especially at position 100 from lysine to glutamic acid, which is known to reduce significantly the binding affinity of mAbs when used to assess group 2 allergens. The detection limit of the developed two-site ELISA was determined to be about 8 ng/ml with rDer f 2 and 1 microg/ml with Derntatophagoides farinae crude extract. The average amount of Der f 2 in dust obtained from bedding samples from 89 homes in Seoul was estimated to be 25.61+/-10.70 microg/g dust. CONCLUSIONS: Assays using mAbs for rDer f 2 could be useful for the assessment of environmental allergen exposure and mAbs could be used to further characterize the isoallergens of Der f 2.     

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

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

Enzyme-Linked Immunosorbent Assay for Determination of Major Excrement Allergens of House Dust Mite Species D. pteronyssinus, D. farinae and D. microceras

Species-specific enzyme-linked immunosorbent assays (ELISA) for major excrement allergens (Dp42, Df6 and Dm6) of D. pteronyssinus, D. farinae and D. microceras in house dust were established, using immunoabsorbed, monospecific rabbit antibodies, coupled to horse radish peroxidase. The limit of detection was 13, 4 and 38 ng/ml, respectively. The coefficient of variation for the entire procedure, including dust sieving (212 micron) and extraction was 5-16% for allergen levels above 1000 ng/g dust. Allergen concentration by ELISA correlated well with the number of mite bodies identified and counted by microscopy in 31 dusts (r = 0.88, 0.86 and 0.82 for combined Dermatophagoides sp., D. pteronyssinus and D. farinae group, resp.) Dermatophagoides allergen was recorded in 21/22 mattress dusts (median: 26,000 ng/g; maximum: 290,000 ng/g). D. pteronyssinus allergen occurred in largest amounts (median 7,500 ng/g) followed by D. microceras (median 650 ng/g) and D. farinae (median 240 ng/g).     

Effect of reduction and heat on the detection of house dust mite (Dermatophagoides pteronyssinus) allergen Der p I by protein blotting

Employment of reducing conditions during sample preparation alters the mobility of the house dust mite (Dermatophagoides pteronyssinus) allergen Der p I as determined by sodium dodecylsulphate-poly-acrylamide gel electrophoresis (SDS-PAGE) from an apparent MW of approximately 25 kD (unreduced) to an apparent MW of approximately 30 kD. Probing of nitrocellulose transfers with sera from subjects allergic to D. pteronyssinus showed that reduction of Der p I was accompanied by a substantial loss of IgE-antibody-binding capacity by this allergen. An important consequence of the effect of reduction on Der p I is that the electrophoretic mobility of this protein becomes very similar to a closely spaced pair of protein-staining bands, probably Der p III, of MWs 30-31 kD. These bands bind IgE antibodies strongly and with high frequency and exhibit the same electrophoretic mobilities under both reducing and non-reducing conditions. Thus, for the clear resolution of allergen Der p I from other IgE-binding components in the same MW region, including Der p III, house dust mite samples for analysis by SDS-PAGE and blotting should not be reduced.     

Inhibition Experiments with Solid Phase Mite or Epithelia in House Dust Hypersensitivity

The present study was undertaken to verify that mites are not the only allergens in house dust extracts and that other allergens such as cat epithelia can also be responsible for house dust hypersensitivities detected both by house dust skin tests and house dust RAST studies. In order to determine whether mite or epithelia fixed on a solid phase could remove not only the IgE antibodies reactive with the homologous allergens, but also the IgE antibodies reactive with house dust allergens, the authors have absorbed 10 sera of house dust allergic patients with solid phase mite or epithelia. The absorption procedure removed a large part of the IgE antibodies reactive with specific immunosorbent (Dermatophagoides pteronyssinus or cat epithelia) and in the same way the IgE antibodies reactive with house dust immunosorbent. The percentage of RAST inhibition varied from 65% to 92% for Dermatophagoides pteronyssinus and from 65% to 94% for house dust in patients allergic to house dust and mite; the percentage of RAST inhibition varied from 67% to 92% for cat epithelia and from 73% to 90% for house dust in patients allergic to house dust and cat epithelia. This is in accordance with the hypothesis that house dust is not an allergen per se, but rather a complex mosaic of several allergens including mite, animal epithelia, etc.     

House dust mite-induced histamine release from washed blood cells

In a selected group of 60 house dust mite allergic asthmatics, the correlation between the bronchial sensitivity to house dust mite and effect parameters of mite-induced histamine release from washed blood cells was evaluated. Using a sensitive glass microfibre-based method, a significant positive correlation (r = 0.60; P less than 0.001) was found between bronchial allergen sensitivity and basophil cell sensitivity expressed as the house dust mite concentration necessary to give half the maximum histamine release. No correlation was found between bronchial sensitivity and other parameters of the histamine release response. This way of determining the histamine release from washed blood cells is a simple and valuable alternative to bronchial allergen challenge.