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Allergen Concentration (allergen + concentration)

Distribution by Scientific Domains

Medical Sciences	100%

Kinds of Allergen Concentration

mite allergen concentration

Selected Abstracts

FS04.6 Dose/unit area and time , key factors influencing the elicitation capacity of MCI/MI

CONTACT DERMATITIS, Issue 3 2004
Claus Zachariae
The objective of the study was to investigate, using the Repeated Open Application Test (ROAT), two key parameters of exposure , allergen concentration (dose/unit area) and time in terms of the elicitation capacity of methylchloroisothiazolinone and methylisothiazolinone (MCI/MI) in MCI/MI-sensitised individuals and to explore the inter-relationship between these two key factors. The study was designed as a double-blind, placebo-controlled, dose-response ROAT preceded by a Diagnostic Patch Test (DPT). 79 patients with a known MCI/M allergy were contacted, 29 were diagnostically patch tested and 25 had their allergy confirmed. 25 MCI/M-allergic subjects and 10 healthy non-allergic control subjects were challenged with 2 ppm of MCI/MI/unit area of skin for 4 weeks. After a wash out period of at least 4 weeks the subjects were challenged with 7.5 ppm of MCI/MI/unit area of skin for 4 weeks. A ROAT with 2 drops of solution twice a day was conducted on the volar aspect of the left and right forearms on a 3 × 3 cm area resulting in dose/unit area of MCI/MI of 0.025 mg/cm2 and 0.095 mg/cm2 for 2 ppm and 7,5 ppm MCI/MI respectively. The elicitation capacity of MCI/MI in MCI/MI sensitive patients is dependent on the exposure dose/unit area and time The results of this study will be a useful addition to the risk assessment information available for MCI/MI. The risk assessment for the use of MCI/MI in rinse off consumer products is unaffected by the results of this study. [source]

Major mite allergen Der f 1 concentration is reduced in buildings with improved energy performance

ALLERGY, Issue 5 2010
F. Spertini
To cite this article: Spertini F, Berney M, Foradini F, Roulet C-A. Major mite allergen Der f 1 concentration is reduced in buildings with improved energy performance. Allergy 2010; 65: 623,629. Abstract Background:, Environmental conditions play a crucial role in mite growth, and optimal environmental control is key in the prevention of airway inflammation in chronic allergic rhinoconjunctivitis or asthma. Objective:, To evaluate the relationship between building energy performance and indoor mite allergen concentration in a cross-sectional study. Methods:, Major allergen concentration (Der f 1, Der p 1, mite group 2, Fel d 1 and Bla g 2) was determined by quantitative dot blot analysis from mattress and carpet dust samples in five buildings designed for low energy use (LEB) and in six control buildings (CB). Inhabitants had received 4 weeks prior to mite measurement a personal validated questionnaire related to the perceived state of health and comfort of living. Results:, Cumulative mite allergen concentration (with Der f 1 as the major contributor) was significantly lower in LEB as compared with CB both in mattresses and in carpets. In contrast, the two categories of buildings did not differ in Bla g 2 and Fel d 1 concentration, in the amount of dust and airborne mould collected. Whereas temperature was higher in LEB, relative humidity was significantly lower than in CB. Perceived overall comfort was better in LEB. Conclusions:, Major mite allergen Der f 1 preferentially accumulates in buildings not specifically designed for low energy use, reaching levels at risk for sensitization. We hypothesize that controlled mechanical ventilation present in all audited LEB may favour lower air humidity and hence lower mite growth and allergen concentration, while preserving optimal perceived comfort. [source]

Characterization and comparison of commercially available mite extracts for in vivo diagnosis

ALLERGY, Issue 2 2010
B. Brunetto
To cite this article: Brunetto B, Tinghino R, Braschi MC, Antonicelli L, Pini C, Iacovacci P. Characterization and comparison of commercially available mite extracts for in vivo diagnosis. Allergy 2010; 65: 184,190. Abstract Background:, Assessment of sensitization by allergen-specific IgE testing and skin prick testing (SPT) are primary tools in routine clinical diagnosis of allergies. To perform a correct diagnosis, it is critical that the allergen reagent used contains an adequate amount of all relevant components. This study aimed at evaluating commercially available mite extracts for in vivo diagnosis from eight manufacturers. Methods:, Eight extracts from Dermatophagoides pteronyssinus and eight from Dermatophagoides farinae were analysed for total protein content by Bradford and for major allergen content by ELISA. SDS-PAGE, immunoblotting and SPT were also carried out. Results:, The protein amount ranged from 27.7 ,g/ml extract to 361.1 ,g/ml (D. pteronyssinus) and from 20.3 to 353.0 ,g/ml (D. farinae). In regards major allergen concentration, Der p 1 ranged from 9.6 to 36.2 ,g/ml, Der f 1 26.5,196.1 ,g/ml, mite group 2 0.7,31.7 ,g/ml in D. pteronyssinus and 1.3,10.4 ,g/ml in D. farinae. SDS-PAGE experiments showed that some components are poorly represented or absent in extracts from most manufacturers. Similar results were obtained by IgE-immunoblotting and SPT with 10 mite allergic patients confirmed a broad spectrum of reactivity of the extracts in the same subject. Conclusions:, Immunochemical analysis showed a heterogeneous amount of component/s among mite extracts from different manufacturers. These data were confirmed by in vivo testing, suggesting that, for some of the patient tested, the absence of relevant allergens could strongly affect the diagnosis. [source]

Allergen content of grass pollen preparations for skin prick testing and sublingual immunotherapy

ALLERGY, Issue 10 2009
I. Sander
Background:, The allergen content of diagnostics and immunotherapeutics is crucial for effective diagnosis and treatment. The aim of this study was to quantify and compare the allergen content of different grass pollen preparations for skin prick testing and sublingual immunotherapy (SLIT). Methods:, Five skin prick test (SPT) solutions and 10 sublingual immunotherapeutics were analysed for protein and allergen concentration by Bradford assay, inhibition of IgE-binding to Phleum pratense ImmunoCAPs and content of the main allergen Phl p 5 by two-site enzyme immunoassay. In addition, the grass pollen preparations were compared by sodium dodecyl sulfate,polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting analyses. Results:, Protein concentrations of SPT solutions ranged from 15 to 427 ,g/ml, and Phl p 5 concentrations ranged from 0.15 to 18.3 ,g/ml. The ranking of SPT solutions concerning Phl p 5 content and IgE inhibition capacity was the same, and the ranking of protein and allergen content was closely correlated (r = 0.9). Protein content of the maintenance doses of the immunotheurapeutics ranged from 5 to 153 ,g, Phl p 5 content ranged from 0.2 to 21.6 ,g. IgE inhibition capacity of the maintenance doses was closely correlated to their Phl p 5 and protein content. SDS-PAGE and immunoblots confirmed the differences in protein and allergen content. Conclusions:, Grass pollen preparations for SPT and SLIT varied greatly concerning protein and allergen content. Whereas this result corresponds to previous analyses results of SPT solutions, it was the first comparison of grass pollen immunotherapeutics. For diagnosis and therapy, these differences should be taken into account. [source]

Window pane condensation and high indoor vapour contribution , markers of an unhealthy indoor climate?

CLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2000
Emenius
Objective The aim of this study was to investigate whether window pane condensation and indoor vapour contribution , 3 g/m3 could be used as indicators of defective air change rate, high indoor humidity and high mite allergen concentration in mattress dust. Methods Actual ventilation rate, indoor temperature, air humidity (AIH/RH) and concentrations of mite allergen were measured in 59 houses and compared with received outdoor temperatures and air humidity. Indoor vapour contribution defined as the difference between the indoor and the outdoor vapour concentration was calculated. Sensitivity, specificity, predictive values and accuracy were calculated for window pane condensation and high vapour contribution (, 3 g/m3), as indicators of defective ventilation (< 0.5 ACH), high indoor humidity (, 7 g/kg and , 45% RH) and high mite allergen concentration in mattress dust (, 2 ,g/g). Results All houses with high humidity and high mite allergen concentrations were positive for the two indicators (high sensitivity), but with a specificity of only 50% so that half of the houses with reported condensation and high vapour contribution turned out to be low pollution houses with adequate high ventilation levels. Both indicators had high negative predictive values and absence of the two indicators almost certainly (97,100%) excluded high indoor pollution with high humidity and high mite concentrations. Overall more than 70% of the dwellings were correctly classified by the two indicators. Conclusion Absence of window pane condensation on double-glazed windows and low indoor vapour contribution (< 3 g/m3) during the winter are true markers of a dwelling without high indoor air humidity and without high mite allergen concentrations in mattress dust in houses in a cold temperate climate with subzero outdoor temperatures. The presence of the two indicators is associated with a 18,45% risk of high humidity and mite allergen concentrations so in this latter group further measurements are needed for correct classification. [source]

P28 Interleukin-8 from keratinocytes can be used to test for contact allergy

CONTACT DERMATITIS, Issue 3 2004
Bolli Bjarnason
Objective:, To investigate whether secretion of interleukin-8 (IL-8) proteins by keratinocytes following in vitro exposure to a contact allergen can be used to detect contact allergy. Methods:, Suction blisters were made on skin of allergic and anergic subjects to urushiol, the contact allergen of poison ivy. Keratinocyte cultures were prepared and exposed to the allergen in vitro. Controls were the allergen solvent. Variable allergen concentrations, allergen exposure times and cell culture times were used. At the end of each culture time, IL-8 RNA and protein of the culture supernatants were analyzed by PCR and ELISA. Results:, The concentration of IL-8 in the supernatants proved to be a successful way to distinguish between subjects who patch tested positive with a non-toxic concentration of urushiol and subjects who tested negative. In the allergic subjects, a correlation was established between the dose of the allergen and the IL-8 protein concentration in the supernatants. Conclusions:, In vitro testing of contact allergies in patients makes possible an objective assessment of their allergic status without causing a booster effect or risking active sensitizations. The results indicate that the method may be used as an alternative method to animal models for testing consumer products before their marketing, thus avoiding ethical problems and problems related to interpretation of tests because of biological differences between animals and humans. [source]

Cigarette smoke facilitates allergen penetration across respiratory epithelium

ALLERGY, Issue 3 2009
K. Gangl
Background:, The association between cigarette smoke exposure and allergic airway disease is a matter for debate. We sought to investigate in an in vitro system whether active smoking reduces the integrity and barrier function of the respiratory epithelium and thus facilitates allergen penetration. Methods:, We cultured the human bronchial epithelial cell line 16HBE14o, in a transwell culture system as a surrogate for the intact respiratory epithelium. The cell monolayer was exposed to standardized cigarette smoke extract (CSE). The extent and effects of trans-epithelial allergen penetration were measured using 125I-labelled purified major respiratory allergens (rBet v 1, rPhl p 5 and rDer p 2) and histamine release experiments. Results:, Exposure of cells to concentrations of CSE similar to those found in smokers induced the development of para-cellular gaps and a decrease in trans-epithelial resistance. CSE exposure induced a more than threefold increase in allergen penetration. Increased subepithelial allergen concentrations provoked a substantial augmentation of histamine release from sensitized basophils. Conclusions:, Our results indicate that cigarette smoke is a potent factor capable of reducing the barrier function of the respiratory epithelium for allergens and may contribute to increased allergic inflammation, exacerbation of allergic disease and boosting of IgE memory. [source]

Variation of dust endotoxin concentrations by location and time within homes of young children

PEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 3 2010
Dennis R. Ownby
Ownby DR, Peterson EL, Williams LK, Zoratti EM, Wegienka GR, Woodcroft KJ, Joseph CLM, Johnson CC. Variation of dust endotoxin concentrations by location and time within homes of young children. Pediatr Allergy Immunol 2010: 21: 533,540. © 2010 John Wiley & Sons A/S Endotoxin may affect the development of allergic disease in childhood but little is known about endotoxin variation within homes. We sought to determine endotoxin concentration agreement within homes when five locations were each sampled twice 5 months apart. Endotoxin was measured using the recombinant Limulus factor C assay in dust samples from 585 homes of children enrolled in a prospective study and again in 335 homes 5 months later. The five locations sampled in each home were the child's bedroom floor, child's bed, mother's bedroom floor, mother's bed and living room floor. Concentrations of 4 allergens (Can f 1, Fel d 1, Der f 1 and Bla g 2) were also measured from the child's bedroom floor. In pair-wise comparisons, endotoxin concentrations in all locations within each home were significantly different from all other locations (p < 0.001) except for the child's and mother's bedroom floors (p = 0.272). Spearman correlations between endotoxin concentrations from the different locations were all statistically significant (p < 0.05) but of modest magnitude (r = 0.24,0.54). Similarly, correlations at each site over the 5 month observation interval were statistically significant but modest (r = 0.17,0.44). Pets and season of the year did not affect correlations, although correlations were lower if the floor was not carpeted. Endotoxin concentrations at all locations were minimally correlated with allergen concentrations in both negative and positive directions (r = ,0.12 to 0.12). We conclude that a single measurement of endotoxin from a home dust sample provides an imprecise estimate of dust endotoxin concentrations in other locations within the home and over a relatively short observation interval. [source]

Allergens, Der p 1, Der f 1, Fel d 1 and Can f 1, in newly bought mattresses for infants

CLINICAL & EXPERIMENTAL ALLERGY, Issue 11 2002
R. De Boer
Summary Background To avoid allergen exposure of newborn babies, the use of a new mattress for the baby bed may be recommended. However, it is not certain that new mattresses are always free of allergens. Objective In the present study the allergen content of new infant mattresses was investigated. Methods Dust samples were vacuumed from 90 new mattresses for infant beds bought in 50 different Dutch shops, and the concentrations of Der p 1, Der f 1, Fel d 1 and Can f 1 were determined by radioimmunoassays. Results Most mattresses contained some allergen and often the allergen concentrations were surprisingly high. Only 15 of the 90 mattresses contained no detectable amounts of any of the four allergens. The highest concentration found for each allergen was 3.1, 46.5, 20.2 and 95.7 µg/g of dust, respectively. However, the total amount of allergen in a mattress was still rather low because the new mattresses contained only modest amounts of dust. Baby mattresses more often contained an increased allergen load than the larger, standard-sized, infant mattresses. This may be caused by differences in manufacturing procedure. Also, mattresses that were sold without a plastic encasement more often contained an increased allergen load. Conclusions It is advisable to buy a mattress that is wrapped in plastic, but it may still contain a substantial amount of allergen. Thorough vacuuming of a newly bought mattress before it is installed on a child's bed, is also advisable. After instalment, regular vacuuming of the mattress and washing of the bed linen as well as measures to eliminate allergen reservoirs in other parts of the house are important, because our observations indicate that mattresses easily pick up allergens from the environment. [source]