Dust from carpeted and smooth floors

Dust samples were collected twice from smooth and carpeted floors in 10 Norwegian schools. The content of antigens and allergens of alder (Alnus incana), birch (Betula verrucosa), timothy (Phleum pratense), cat and dog dander, house dust mite (Dermatophagoides farinae), mould (Cladosporium herbarum), hen egg white and codfish (DIII) were investigated by crossed immunoelectrophoresis (CIE), crossed radio immunoelectrophoresis (CRIE), radio allergosorbent test (RAST) inhibition and quantitative precipitation inhibition analysis by laser nephelometry. Antigens and allergens of cat and dog dander and hen egg white were most prevalent in the dust samples investigated. With the exception of hen egg white and codfish allergens, no statistically significant differences in mean allergen content were shown in identical quantities of freeze-dried dust extracts from carpeted and smooth floors. RAST-inhibition analyses of identical amounts of dust from either floors showed higher content of allergens of cat, dog, hen egg white, codfish, mould and timothy pollen in classrooms with carpets.     

Dust from carpeted and smooth floors. I. Comparative measurements of antigenic and allergenic proteins in dust vacuumed from carpeted and non-carpeted classrooms in Norwegian schools

Dust samples from fitted-carpets and linoleum floors in 12 schools in Norway were collected by vacuum cleaning. The presence of antigens and allergens of alder (Alnus incana), birch (Betula verrucosa), timothy (Phleum pratense), mould (Cladosporium herbarum), house dust mite (Dermatophagoides farinae), cat and dog dander, codfish, hen egg white and human dander were investigated by crossed immunoelectrophoresis (CIE), crossed radio-immunoelectrophoresis (CRIE) and radio-allergosorbent test (RAST) inhibition. No qualitative differences in allergen contents of dust from both types of floor tested were noted. Similarly, no relationship could be demonstrated between floor-type and allergen concentration under identical experimental conditions. Antigens and allergens of both cat and dog were frequently demonstrated in dust extracts. All extracts included human dander and mould allergens. In addition, most dust samples from both carpeted and smooth floors contained hen egg white and codfish allergens. Furthermore, the study demonstrated that dust from smooth floors and fitted-carpets was relatively free of mite and pollen from alder, birch and timothy.     

Der p I concentrations in mattress surface and floor dust collected from infants' bedrooms

Background Allergen exposure in early childhood is thought to be important for sensitization and subsequent development of asthma. Not much is known, however, about exposure of young children to allergens in the home. Objectives This study was designed to document dust mite allergen exposure in young children, and to determine wheither infants from atopic mothers (=‘high-risk’ infants) are exposed to lower concentrations of house dust mite alkrgen than infants from non-atopic parents (=‘low-risk’ infants). Methods Dust samples were taken in the homes of 104 infants (48 ‘high-risk’ and 56 ‘low-risk’ infants, selected by questionnaire) aged 3–15 months, from floors in different rooms and from the child's mattress surface. Results The majority of the infants were found to be exposed to Der p I concentrations of more than 2000 ng/g in dust collected from the surface of their mattresses. Lower Der p I concentrations were found in mattress surface dust from the beds of infants from atopic mothers than of infants from non-atopic parents. Also, lower Der p I concentrations were found in floor dust from the homes of infants from atopic mothers, Infant beds equipped with new mattresses, new blankets and top plastic sheeting had significantly lower Der p I concentrations than beds equipped with used mattresses and blankets, without top plastic sheeting. Conclusions Young children in the Netherlands are exposed to significant concentrations of Der p I in mattress surface dust. Allergic parents appear to provide their children with environments somewhat less rich in mite allergen than non-allergic parents.     

Dust from carpeted and smooth floors

The amounts of dust, protein, and allergens in vacuumed floor covering samples taken from both schools and homes in Norway have been investigated. Classrooms contained significantly more crude dust per unit area than homes, while the mean protein content per unit area was somewhat higher in homes. The main allergen exposure problem in classrooms was that of pet allergens; the contents of dog allergens and the major cat ( Felis domesticus ) allergen Fel d I per unit area were significantly higher in school classrooms than in homes of families who do not keep pets. The mite and food allergens, on the contrary, were more prevalent in homes. Carpeted floors in schools and homes contained significantly more dust, proteins, and allergens than smooth floors (P<0.05). Fel d I was detected in the vacuum cleaners' filter system in concentrations from <1 ng to 1080 ng, confirming that this allergen can pass through the dust bag during vacuuming.     

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.     

Gender differences in indoor allergen exposure and association with current rhinitis

Background Differences between boys and girls in allergic manifestations are well known, and this difference is possibly not attributed to physiological differences alone. Objective We, therefore, investigated whether boys and girls could be exposed to different allergen levels at home and whether indoor allergen levels could be differently associated with rhinitis in boys and girls at 10 years of age. Methods Cat, dog and house dust mite (HDM) allergen levels in mattress dust and interview data regarding current allergic disease were available for 797 10‐year‐old children (360 girls) in The Environment and Childhood Asthma Study in Oslo. Results Girls had higher concentrations of cat and dog allergens in their mattresses compared with boys, also in homes without cats [geometric mean 95% confidence intervals (95% CI): 0.37 (0.31, 0.44) for girls and 0.26 (0.23, 0.30) μg cat allergen/g dust for boys, P=0.002], and without dogs [girls: 0.74 (0.63, 0.86) and boys: 0.55 (0.48, 0.62) μg dog allergen/g dust, P=0.003]. No difference was observed for HDM allergen (Der p 1) levels. Of the 190 (23.8%) children reporting current rhinitis, 144 (75.8%) were sensitized to at least one allergen. The adjusted odds ratio for current rhinitis increased with 1.20 (95% CI: 1.01, 1.42) per 1 μg/g dust increase in Der p 1 for girls (P=0.037), but not for boys (P=0.91). Conclusion Girls had higher levels of cat and dog allergens in mattress dust compared with boys, whereas no difference was observed for Der p 1 allergen. Nevertheless, only increasing levels of Der p 1 and not cat and dog allergens significantly increased the risk of current rhinitis in girls, whereas no significant association was observed for boys. Cite this as: R. J. Bertelsen, C. Instanes, B. Granum, K. C. Lø;drup Carlsen, G. Hetland, K.‐H. Carlsen, P. Mowinckel and M. Løvik, Clinical & Experimental Allergy, 2010 (40) 1388–1397.     

Dust from carpeted and smooth floors: IV. Solid material, proteins and allergens collected in the different filter stages of vacuum cleaners after ten days of use in schools.

The accumulation of dust, proteins and allergens from alder, birch, timothy, cat, dog, mite, hen egg white, codfish and mould in schools was investigated by analysing the content of vacuum cleaners after 10 days of use. The main goals were to compare the dust accumulation on carpeted and smooth floors and to estimate to what degree the three vacuum cleaner filter stages (i.e. the disposable bag, the main filter and the microfilter) collected dust, proteins and allergens. Carpeted floors accumulated more dust, proteins and allergens per unit area than smooth floors. Histamine release studies of some of the dust extracts showed that the dust from carpeted floors released histamine from passively sensitized basophils at concentrations for which dust from smooth floors gave low or no histamine release. The analyses showed that most of the dust, proteins and allergens were retained in the dust bags. Less than 1% of the vacuumed material had accumulated in the main filters, which, according to the manufacturer, detain 99.5% of particles greater than 2 microns. By the use of a scanning electron microscope (SEM), particle deposits were observed in the microfilters. These deposits, which represented less than 0.1% of the total mass, showed no significant allergenic activity. Thus, for the field conditions of this study, the microfilters were not needed for cleaning the exit air of allergens, although they were useful for removing fine (less than 2 microns) particles.     

Prevalence and distribution of indoor allergens in Singapore

Background and aims Immediate hypersensitivity to indoor allergens is known to be associated with allergic asthma. This study evaluated the prevalence and distribution of six indoor allergens in 956 dust samples obtained from homes, childcare centres, schools, and a hospital in tropical Singapore. Seasonality of mite allergens was also assessed. Methods The major allergens of the Dermatophagoides spp. dust mites, Der p l and Der f 1; major cat and dog allergens, Can f 1 (dog) and Fel d 1 (cat); and cockroach, Bla g 1. were measured by specific enzyme immunoassays. Allergen levels of the storage mite. Blomia tropicalis (Blot), were measured by a fluorescent allergosorbent test (FAST) inhibition assay. Results Our results showed that homes had significantly higher concentrations and prevalence of allergens compared with the other locations, except for Bla g 1, where higher mean levels were found in schools. Within the homes, the highest concentrations of mite allergens were found in mattresses (geometric mean: 1.2 μg/g dust Der p 1; 2717 Allergen Units per gram dust [AU/g] Blot), and carpets (1.5 μg/g Der p 1; 1620 AU/g Blo t), whilst Bla g 1 was mainly concentrated in the storerooms (geometric mean = 3.5 units/g) and kitchens (geometric mean = 5.1 units/g). The major cat and dog allergens were well distributed and not confined to homes with pets. Their highest levels were found in dust of soft furnishings, carpets and mattresses. There was an absence of significant seasonal variation in Der p 1, Der f 1 and Blo t levels in the homes over a 1 year period. Conclusion The results indicate that compared with public places, the home consitutes a major reservior of indoor allergens. Allergens of the storage mite, B. tropicalis, should be considered as a major allergenic component of dust in Singapore.     

House dust mites and their allergens at selected locations in the homes of house dust mite-allergic patients

BACKGROUND: Knowledge of the occurrence of house dust mites (HDM) and their allergens in domestic locations is important when planning intervention. OBJECTIVE: The aim of this study was to describe the distribution of HDMs and their allergens before intervention in multiple locations in the homes of newly diagnosed HDM-allergic patients with a known high Der 1 concentration in their mattress dust. METHODS: Dust was collected from ten locations in the homes of eight HDM-allergic patients. Dust was analysed for allergen content with ELISAs for Der f 1, Der p 1 and Der m 1; and HDM were counted. Total allergen concentrations ( micro g Der 1/g dust) were expressed as the sum of Der f 1, Der p 1 and Der m 1. RESULTS: On mattresses the median concentration was 86 micro g Der 1/g dust (range 30-288) and 188 mites/g dust (range 12-1910). Der 1 exceeded 10 micro g/g dust in mattresses (8/8), duvets/pillows (3/8), a bedroom carpet (1/1), a living room carpet (1/6), upholstered furniture (2/8) and a curtain (1/5). Uncarpeted floors, upholstered furniture, bookshelves and walls had significantly lower Der 1 concentration than the mattresses. The relative contribution of Der p 1, Der f 1 or Der m 1 to Der 1 was related to homes, rather than to the location. Der m 1 only occurred in minute amounts. CONCLUSION: For HDM intervention, our results indicate that priority should be given to the removal of allergens from mattresses, and in addition from carpets, duvets/pillows and upholstered furniture. Dust from walls, uncarpeted floors, bookshelves and curtains appear to contribute insignificantly to the domestic HDM allergen load.     

Mite allergens in relation to home conditions and sensitization of asthmatic children from three climatic regions

We investigated the levels of mite (Der p I and Der f I) allergen in dust from bedrooms, living rooms, kitchens, and bathrooms from 130 homes of asthmatic children in three climatic zones of Sweden. Bedroom dust samples included the child's mattress, carpets, floors, and other plain surfaces. Living-room dust samples were taken from sofas and other furniture, carpets, floors, and other plain surfaces. The allergen levels were related to home characteristics, including absolute indoor humidity (AIH), relative humidity (RH), and air changes per hour (ach). Mite allergen was detected in 62% of the homes. Levels of Der p I varied between <16 ng and 50 μg/g dust, and Der f I between ≤16 ng and 73 μg/g dust. Because we have designed a composite type of dust collection in our study, the allergen levels found tend to average down the results. Mite allergen levels were higher in homes with dampness problems, in homes with a smoker, and in homes without a basement. Homes with high absolute humidity (7 g/kg) or relative humidity (45%) and poor ventilation (≤0.5 ach) contained higher levels of mite allergens than homes with lower humidity and better ventilation. However, the number of ach measurements in homes was not high, and few homes had ≤0.5 ach. Sensitization to house-dust mites was more common in southern than in northern and central Sweden. High levels of house-dust mite allergen in a temperate climate where mites are not ubiquitous are thus associated with dampness problems in homes and with tobacco smoking. Our data confirm and extend previous findings that high AIH and RH and poor ventilation increase the risk of mite infestation in homes. It seems to be important and necessary to control indoor humidity and ventilation levels, to avoid high mite allergen exposure in a temperate climate, because 34% of mite-sensitized asthmatic children were exposed to levels of mite allergen >2 μg/g dust in their homes. The study also shows that mite allergen levels below the suggested threshold level (2 μg/g dust) are associated with mite sensitivity in children with perennial symptoms of asthma.     

Mite allergens during 18 months of intervention

Wickman M, Nordvall SL, Pershagen G, Korsgaard J, Johansen N, Sundell J. Mite allergens during 18 months of intervention.
In Stockholm, Sweden, 17 children with newly diagnosed sensitization to house-dust mites (HDM) and 11 children with previously diagnosed HDM-sensitization were included in a study of HDM-allergen avoidance. Mattress dust was collected on repeated occasions during 18 months and assayed for concentration of major HDM allergens. During the first 12 months, the parents of the intervention group were instructed to intensify cleaning and airing of the child's bedroom. During the last 6 months of the study, the mattresses and pillows of seven children in the intervention group and sibling controls were encased in semipermeable polyurethane covers. The homes exhibited a high absolute indoor humidity throughout the year, and even during the winter the mean levels exceeded 7 g/kg. No mite allergen reduction was seen in the intervention group during the first year. However, among the newly diagnosed HDM-sensitized children, there was a mean reduction of the mattress mite allergen concentration of 83% ( P = 0.02), and this was most pronounced in the homes with low humidity. At the end of the mattress encasement period, an average difference of 98% ( P < 0.001) was found between the vacuumed amount of mite allergen on top of the covers and that underneath.     

New mattresses: how fast do they become a significant source of exposure to house dust mite allergens?

Background Sensitization and exposure to mile allergens is a major risk factor for asthma. Little is known about the rate of build-up of allergens in the mite microhabitats. Objectives To investigate the rate of increase in mite allergen levels in new mattresses. Methods Der p 1 was measured in the dust samples collected from six identical new single mattresses over a period of 2 years. Results Der p 1 increased significantly at 4 months as compared with baseline level (P < 0.01), but no difference was found between the concentrations at 4. 8, 12 and 24 months. There was a significant correlation between Der p 1 concentration in mattresses at 4.8, 12 and 24 months and Der p 1 levels in the bedroom carpet at the beginning of the study. Conclusions New mattresses can become a significant source of exposure to mite allergens after a short period of time (< 4 months). There is little justification for advising mite sensitive patients to replace their mattresses as a part of avoidance regime.     

Mite antigen in house dust: relationship with different housing characteristics in the Netherlands

As part of a case-controlled study on the relationship between home dampness and respiratory symptoms of children, the concentration of the major allergen of Dermato-phagoides pteronyssinus (Der p I) in floor dust and mattress dust in 516 dwellings in the Netherlands was measured. A checklist, completed by the investigators, was used to obtain information on home and occupant characteristics, which may have an impact on the Der p I concentration in house dust. The geometric mean mite antigen concentrations were 2370 ng Der p I/g floor dust for the living room, 2201 ng Der p I/g floor dust for the bedroom and 5075 ng Der p I/g mattress dust. In 86% of the houses the maximum concentration was higher than 2000 ng Der p I/g dust, that is regarded as representing a risk for genetically predisposed individuals for the development of specific IgE to house dust mite allergen. In 55% of the houses the maximum concentration exceeded 10000 ng Der p I/g dust, regarded as a risk factor for acute attacks of asthma for mite allergic patients. The Der p I concentrations in dust from carpeted floors were six to 14 times higher than in dust from floors with a smooth floor covering. Higher Der p I concentrations in floor dust were also significantly associated with increasing age of the dwelling and of the floor covering, with an increasing number of occupants, and with the absence of floor insulation. For mattress dust, the age of the mattress, the presence of an outer cavity wall and mechanical ventilation were important factors. Older mattresses had higher levels, and mattress dust from bedrooms with solid brick outer walls had higher levels than that from bedrooms with outer cavity walls. Mattresses in homes with continuous mechanical ventilation had almost twice lower levels than mattresses in homes with natural ventilation. There was a tendency towards higher Der p I concentrations in dust in homes with reported or observed signs of dampness. The Der p I concentrations in dust from carpeted bedroom floors and mattresses were positively associated with the average relative humidity in the bedroom over a period of 3–6 weeks in a subset of the homes where relative humidity was measured. Similar results were obtained using the concentrations of Der p I in ng/m² instead of ng/g dust. The results obtained in this study are of importance for planning and evaluating allergen avoidance measures advised to mite allergic patients.     

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

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 microg/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.     

Effects of IL-4 and IL-13 on total and allergen specific IgE production by cultured PBMC from allergic patients determined with recombinant pollen allergens

Background: Interleukin (IL)-4 and IL-13 have been shown to be potent switch factors for IgE synthesis in human B cells. Objective: In this study we investigated the effects of recombinant human IL-4 and IL-13 on total and allergen specific IgE synthesis by peripheral blood inononuclear colls (PBMC) from pollen allergic patients and healthy control individuals. Methods: Peripheral blood mononuclear cells (PBMC) from allergic patients were investigated for their capacity to produce allergen specific IgE in vitro. Total protein extracts from birch pollen and timothy grass pollen as well as purified recombinant birch pollen allergens, Bet v I, birch profiling (Bet v II) and recombinant timothy grass pollen allergens. Phi p I, Phi p II, and Phi p V were used to measure specific IgE-antibody synthesis in cell culture supernatants by IgE-immunoblot and ELISA. Reults PBMC obtained from allergic patients spontaneously secreted allergen specific IgE in the culture supernatants. Addition of Interleukin 4, Interleukin 13 and anti-CD40 antibody to the cultures alone or in combinations significantly induced total IgE production whereas allergen specific IgE production was not affected. Conclusion: Our results indicate that the peripheral blood of allergic individuals contains long lived allergen specific B cells which have already switched to IgE production and which are not sensitive to IL-4 and IL-13 treatment. These results may have implications on attempts to use cytokines or cytokine antagonists in therapy of Type I allergy.     

Allergen avoidance in the homes of atopic asthmatic children: the effect of Allersearch DMS

Allersearch DMS (an alcohol based purified benzyltannate complex) is an acaricide with allergen denaturing properties. The living rooms in the homes of 16 atopic asthmatic children were thoroughly cleaned and treated with Allersearch DMS and the effect on allergen concentrations in carpet and soft-furnishing dusts was determined. The skintest reactivity of the children to their own dust, collected before and after treatment, was compared. In 13 of the 16 homes the concentration of major house dust mite allergen Der p I was reduced in the carpet dust after treatment (P< 0.001) and in 11 homes major cat allergen Fel d I was reduced (P= 0.03). Changes in allergen concentrations in soft-furnishing dusts were not significant. Control homes, which were cleaned but not treated, showed no significant difference in allergen concentrations. There were highly significant reductions in skin-test reactivity to both types of dust after treatment (P<0.004, P< 0.008) suggesting an effect of the compound on allergens other than those individually monitored. The change in skin-test response to soft-furnishing correlated significantly (P< 0.05) with the number of individual sensitivities detected in each child. Controlled clinical trials of the effect of Altersearch DMS as part of an allergen avoidance study are now necessary.     

Mite (Der p I, Der f I), cat (Fel d I) and dog (Can f I) allergens in dust from Swedish day-care centres

Early exposure to allergens is important for sensitization to inhalant allergens and it has been reported that there is a causal relationship between allergen exposure and bronchial asthma. We investigated the levels of major mite (Der p I/Der f I), cat (Fel d I) and dog (Can f I) allergen levels in dust collected from various locations in seven day-care centres (22 sections). The allergen levels were related to the characteristics of the day-care centres. Children and staff were questioned about contacts with animals, and cleaning personnel were asked about methods and frequency of cleaning. Mite allergen was found in nine of the 22 sections. The concentrations varied between < 16 ng/g and 106 ng/g dust (median < 16 ng/g). Mite allergen was not detected in any floor dust sample. Cat and dog allergen was detected in all centres and sections. The concentrations of dog allergen (median 4.3 μg/g; range < 60 ng-21 μg/g) were significantly higher (P < 0.05) than that of cat allergen (median 1.6 μg/g; range < 16 ng-22.8 μg/g). Higher amounts of both Fel d I and Can f I were observed on mattresses/sofas/cushion like toys and curtains than on tables/chairs and floors. The levels of cat or dog allergen on floors significantly correlated with the total number of children and staff with either a cat or a dog at home and or frequent contacts with them. Neither cleaning methods nor the frequency of cleaning influenced the allergen concentrations. The concentration of Fel d I was significantly lower (P < 0.05) in washed than in never washed curtains. We conclude that Fel d I and Can f I allergens are ubiquitous in day-care centres. The allergens are probably carried there in the clothes of children and staff. Day-care centres should be considered a cause of exposure to indoor allergens. Curtains, toys and upholstery were the most important reservoirs. We suggest that the concentration of allergen in curtains reflects long-term exposure to airborne indoor allergens, since they are mainly exposed to airborne allergens.     

Mite fauna, Der p I, Der f I and Blomia tropicalis allergen levels in a tropical environment

Fifty dust samples were collected from the mattresses and bedroom floors of 25 subjects with allergic asthma in Cartagena, Colombia, in order to identify house dust mites and quantitate Der p I, Derf I and Blomia tropicalis allergens. The geometric mean of the total mite density per gram of dust was 418 (range, 40–2280). Twenty-two samples (44%) had more than 500 mites and four, less than 100. B. tropicalis and Dermatopha-goides pteronyssinus were found in 96% and 90% of the samples, accounting for 40.1% and 35.7% of the total mites, respectively. Cheyletus malaccensis, Chortoglyphus arcuatus, Pyroglyphus africanus, Orihatids, Grallacheles bakeri. Tarsonemus spp., Suidasia spp., Dermatophagoides farinae and unidentified mites accounted for the rest. The geometric mean of the total mites/gram of dust in mattresses (563.9) was significantly higher than in floor dust (309. 1), P < 0.01. Allergen concentrations and mite numbers were analysed by Spearman rank correlations: B. tropicalis mites vs B. tropicalis allergen, r= 0.54, P<0.001; D. pteronyssinus mites vs Der p I, r= 0.52, P< 0.001. A negative correlation was obtained between B. tropicalis mites and Der p I. Allergens derived from B. tropicalis and other domestic mite species may play an important role in sensitization and allergic symptoms in Cartagena, Colombia.     

Fetal Cord Blood: Aspects of Heightened Immune Responses

Neonatal immune responses have been associated with the development of atopy in childhood. We assessed in cord blood mononuclear cells (CBMC) whether increased allergen/mitogen-induced lymphoproliferation (LP) is associated with pro-allergic Th2 cytokine IL-13 or Th1 cytokine IFN-γ secretion. We determined whether LP to one allergen is related to heightened lymphocyte function to other allergens/mitogen. CBMC from 135 neonates were stimulated with house dust mite (Derf1), cockroach, ovalbumin, or mitogen. LP to one allergen was associated with significantly increased LP to other allergens/mitogen. Increased Derf1-LP was associated with increased Derf1-induced IL-13 secretion (r = 0.21, p = 0.01). After adjusting for neonatal gender, race, and maternal smoking, Derf1-LP remained associated with Derf1-IL-13 (OR 3.08, 95% CI 1.56–6.10). Increased mitogen-induced proliferation was associated with increased mitogen-induced IL-13 secretion (r = 0.37, p < 0.001). For some individuals, a predisposition to a heightened immune response is already evident at birth. Whether this phenotype results in atopy in childhood warrants further investigation.     

The allergen profile of beech and oak pollen

Background Beech and oak pollen are potential allergen sources with a world‐wide distribution. Objective We aimed to characterize the allergen profile of beech and oak pollen and to study cross‐reactivities with birch and grass pollen allergens. Methods Sera from tree pollen‐allergic patients with evidence for beech and oak pollen sensitization from Basel, Switzerland, (n=23) and sera from birch pollen‐allergic patients from Vienna, Austria, (n=26) were compared in immunoblot experiments for IgE reactivity to birch (Betula pendula syn. verrucosa), beech (Fagus sylvatica) and oak (Quercus alba) pollen allergens. Subsequently, beech and oak pollen allergens were characterized by IgE inhibition experiments with purified recombinant and natural allergens and with allergen‐specific antibody probes. Birch‐, beech‐ and oak pollen‐specific IgE levels were determined by ELISA. Results Beech and oak pollen contain allergens that cross‐react with the birch pollen allergens Bet v 1, Bet v 2 and Bet v 4 and with the berberine bridge enzyme‐like allergen Phl p 4 from timothy grass pollen. Sera from Swiss and Austrian patients exhibited similar IgE reactivity profiles to birch, beech and oak pollen extracts. IgE levels to beech and oak pollen allergens were lower than those to birch pollen allergens. Conclusion IgE reactivity to beech pollen is mainly due to cross‐reactivity with birch pollen allergens, and a Phl p 4‐like molecule represented another predominant IgE‐reactive structure in oak pollen. The characterization of beech and oak pollen allergens and their cross‐reactivity is important for the diagnosis and treatment of beech and oak pollen allergy.