Search PubMed⌕ Search

Biomedical subjects

M van Hage-Hamsten

Publications and source records attributed to M van Hage-Hamsten.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effectiveness of occlusive bedding in the treatment of atopic dermatitis--a placebo-controlled trial of 12 months' duration.

BACKGROUND: Several studies on avoidance of house-dust-mite (HDM) and cat allergens have been carried out, most of them in asthmatic patients and only a few in patients with atopic dermatitis (AD). No study so far has focused on which subgroup of AD patients benefits from avoidance measures. METHODS: Forty adult patients with AD completed the 12-month avoidance study. They were divided into an active treatment (n = 22) and a placebo (n = 18) group. Active treatment comprised use of polyurethane-coated cotton encasings for bedding, and placebo use of cotton covers. Patients came for regular checkups during the 12-month period, when eczema severity was assessed and blood samples were analyzed for total IgE, HDM- and cat-specific IgE and soluble CD30 (sCD30) in serum. Dust samples were collected from mattresses before treatment and after 3, 6, and 12 months, and analyzed for content of HDM and cat allergen. RESULTS: Eczema severity decreased significantly in both groups (P < 0.001), with a more pronounced decrease in patients with active covers. The HDM exposure decreased significantly in the active treatment group (P < 0.001), and the levels of HDM-specific IgE were reduced (P<0.05). Exposure to cat allergens was unchanged in the active treatment group but decreased, albeit not significantly (P=0.19), in the placebo group. sCD30 levels were significantly reduced in both groups (P<0.001). Patients not sensitized to HDM allergens benefited from the bedcovers as much as sensitized patients. CONCLUSIONS: Occlusive bedding significantly reduced HDM exposure in bed (P<0.001) and eczema severity, and sCD30 levels decreased significantly (P<0.001). Patients not sensitized to HDM and not exposed to HDM allergens benefited equally from use of the bedcovers, a result which could be due to a reduction of other important allergens, superantigens, or irritants in bed. We therefore recommend the use of bedcovers as part of treatment for AD.

Adult↗
PubMed2001

A revised nomenclature for allergy. An EAACI position statement from the EAACI nomenclature task force.

This report has been prepared by an EAACI task force representing the five EAACI Sections and the EAACI Executive Committee composed of specialists that reflect the broad opinion on allergy expressed by various clinical and basic specialties dealing with allergy. The aim of this report is to propose a revised nomenclature for allergic and related reactions that can be used independently of target organ or patient age group. The nomenclature is based on the present knowledge of the mechanisms which initiate and mediate allergic reactions. However, the intention has not been to revise the nomenclature of nonallergic hypersensitivity.

Humans↗
PubMed2001

Cloning of three new allergens from the dust mite Lepidoglyphus destructor using phage surface display technology.

The dust mite Lepidoglyphus destructor is a common species in Europe and a major cause of dust mite allergy in rural surroundings, but it also contributes to dust mite allergy in urban areas. One major allergen, Lep d 2, has been expressed as a recombinant protein and evaluated both in vivo and in vitro and shown to detect 60% or more of L. destructor-sensitized subjects. Additional recombinant allergens are needed to obtain a reliable diagnostic tool for L. destructor allergy. The aim of this study was to clone and express new allergens from L. destructor and determine their recognition frequency among sensitized individuals. A phage display cDNA expression library was constructed and screened with sera from L. destructor-sensitized individuals. The cDNAs encoding the allergens were cloned into the pET17b vector and subsequently expressed in Escherichia coli as C-terminal His6-tagged proteins. Immunoblotting of the recombinant proteins was performed using sera from 45 subjects allergic to L. destructor. Three new allergens from L. destructor, Ld 5 (originating from a partial Lep d 5 clone), Lep d 7 and Lep d 13, were identified and recognized by 4/45 (9%), 28/45 (62%) and 6/45 (13%) sera from L. destructor-sensitized subjects, respectively.

Allergens↗
PubMed2001

Cross-reactivity studies of a new group 2 allergen from the dust mite Glycyphagus domesticus, Gly d 2, and group 2 allergens from Dermatophagoides pteronyssinus, Lepidoglyphus destructor, and Tyrophagus putrescentiae with recombinant allergens.

BACKGROUND: Dust mites are important inducers of allergic disease. Group 2 allergens are recognized as major allergens in several mite species, including Dermatophagoides pteronyssinus, Lepidoglyphus destructor, and Tyrophagus putrescentiae. No allergens have thus far been characterized on the molecular level from the dust mite Glycyphagus domesticus. OBJECTIVE: We sought to examine the cross-reactivity among group 2 allergens of G domesticus, L destructor, T putrescentiae, and D pteronyssinus. METHODS: A group 2 allergen from G domesticus, Gly d 2, was cloned and expressed as a recombinant protein. Cross-reactivity between Gly d 2 and 3 other group 2 allergens, Lep d 2, Tyr p 2, and Der p 2, was studied by using individual sera and a serum pool RAST-positive to G domesticus, L destructor, T putrescentiae, and D pteronyssinus. Recombinant allergens were used as inhibitors of IgE binding in immunoblotting experiments. Molecular modeling on the basis of the Der p 2 structure was carried out for Gly d 2, Lep d 2, and Tyr p 2. RESULTS: Two cDNAs encoding isoforms of Gly d 2 were isolated, but only the Gly d 2.02 isoform was used in this study. Sixteen of 17 subjects had IgE to Gly d 2. The protein sequence of Gly d 2 revealed 79% identity to Lep d 2 and 46% and 41% identity to Tyr p 2 and Der p 2, respectively. Extensive cross-reactivity was demonstrated among Gly d 2, Lep d 2, and Tyr p 2, but little cross-reactivity was found between these allergens and Der p 2. According to the tertiary structure of Der p 2 and 3-dimensional models of Gly d 2, Lep d 2, and Tyr p 2, differences reside mainly in surface-exposed residues. CONCLUSION: Gly d 2 showed high sequence homology to Lep d 2. Cross-reactivity was observed between Gly d 2, Lep d 2, and Tyr p 2, but only limited cross-reactivity was demonstrated between these 3 allergens and Der p 2.

Allergens↗
PubMed2001

The molecular basis of antigenic cross-reactivity between the group 2 mite allergens.

BACKGROUND: Mite group 2 allergens Der p 2, Der f 2, and Eur m 2 are 14-kDa proteins of unknown function that share 83% to 85% amino acid sequence identity. Isoforms of the allergens within each genus have been identified which differ by 3 or 4 amino acids, but little is known of the influence of group 2 polymorphisms on human IgE antibody binding. OBJECTIVE: The purpose of this study was to investigate the importance of interspecies and isoform substitutions on murine mAb and IgE antibody binding and on the molecular structure of the group 2 allergens. METHODS: Site-directed mutagenesis was used to incorporate the isoform amino acid substitutions onto the Der p 2.0101 sequence. Recombinant allergens were expressed and purified from Escherichia coli and used to evaluate antibody binding by enzyme-linked immunosorbent assay (ELISA). Molecular modeling of the tertiary structure was used to analyze structural differences between the various group 2 allergens. RESULTS: The substitution of asparagine for aspartic acid at position 114 restored mAb binding of rDer p 2.0101; the other Der p 2 isoforms and the 3 rDer f 2 isoforms also reacted in the 2-site ELISA. The correlation of IgE binding to the Der p 2 isoforms was excellent and tended to be higher in the isoforms with the asparagine 114 substitution (r (2) = 0.87 vs r (2) = 0.95). rEur m 2.0101 bound to all mAb except 7A1; when compared with rDer p 2 for IgE binding, rEur m 2.0101 gave a correlation coefficient of r (2) = 0.68. Molecular modeling revealed that Eur m 2 and the storage mite homologs Lep d 2 and Tyr p 2 retain the tertiary fold of Der p 2. Eur m 2 has a conserved surface, whereas Lep d 2 and Tyr p 2 present most of the amino acid substitutions on this surface. Lep d 2 and Tyr p 2 did not react with mAb or with sera from patients with IgE to Dermatophagoides species. CONCLUSION: The isoform substitutions of rDer p 2 can be distinguished by mAb. The allergenic cross-reactivity between Der p 2, Der f 2, and Eur m 2 is a direct result of the conserved antigenic surface, whereas the lack of cross-reactivity with Lep d 2 and Tyr p 2 is a result of the multiple substitutions across this surface.

Amino Acid Sequence↗
PubMed2001

A hypoallergenic derivative of the major allergen of the dust mite Lepidoglyphus destructor, Lep d 2.6Cys, induces less IgE reactivity and cellular response in the skin than recombinant Lep d 2.

BACKGROUND: The major allergen of the dust mite Lepidoglyphus destructor, Lep d 2, has been produced as a recombinant allergen (rLep d 2) with IgE reactivity both in vivo and in vitro. A modified form of rLep d 2 (rLep d 2.6Cys) obtained by site-directed mutagenesis has been shown to have a reduced IgE reactivity in vitro. In this study we have compared the ability of rLep d 2 and rLep d 2.6Cys to elicit positive skin prick tests and cellular responses among L. destructor-sensitized subjects. METHODS: Seventeen subjects were skin prick-tested with rLep d 2, rLep d 2.6Cys, histamine and negative controls and 17-20 h later skin biopsy specimens were taken from the skin prick-tested sites. The biopsy specimens were stained immunohistochemically for EG2+, CD3+, CD1a+, mast cell tryptase+, and IgE+ cells. Dermal cell infiltrates were judged in hematoxylin and eosin staining. Total IgE and allergen-specific IgE were determined by CAP-RAST. RESULTS: Compared to rLep d 2, rLep d 2.6Cys induced significantly smaller and fewer skin prick test reactions (p < 0.001) and dermal cell infiltrates (p < 0.05). Further, rLep d 2.6Cys induced fewer EG2+ cells (p < 0.001) but more tryptase+ cells (p < 0.05) than rLep d 2. A positive RAST to rLep d 2 was obtained for 88.2% of the subjects, while only 35.2% displayed a positive RAST to rLep d 2.6Cys. CONCLUSION: This study demonstrates that rLep d 2.6Cys is less able to evoke IgE-mediated reactions and cellular responses, as measured both in skin and in serum, than rLep d 2. In the future this hypoallergenic derivative may be a promising candidate molecule for immunotherapy of L. destructor-allergic patients.

Adult↗
PubMed2001

IgG1, IgG4 and IgE antibody reactivity to mutant forms of the major dust mite allergen Lep d 2 among atopic and nonatopic subjects naturally exposed to Lepidoglyphus destructor.

BACKGROUND: Lepidoglyphus destructor is a common dust mite causing IgE-mediated sensitization. The major allergen, Lep d 2, has previously been cloned and expressed as several double Cys to Ser mutants with the purpose of producing hypoallergenic variants for immunotherapy. Our aim was to investigate the reactivity pattern of IgG1, IgG4 and IgE antibodies to wild-type (wt) rLep d 2 and four mutants among atopic and nonatopic subjects in relation to sensitization and exposure to L. destructor. METHODS: Inhibition and sandwich ELISA were used to compare IgG1, IgG4 and IgE antibody reactivities to rLep d 2 variants in serum of 20 atopic and 18 nonatopic farmers naturally exposed to L. destructor. A group of 22 urban subjects served as controls. RESULTS: Atopic farmers demonstrated correlating IgE and IgG4 levels to rLep d 2(wt) (rs = 0.70; p < 0.0001) which were significantly (p < 0.0001) higher than those of nonatopic farmers and urban controls. No IgG4 antibodies were detected in nonatopic farmers despite chronic allergen exposure. A parallel reactivity pattern of IgE and IgG4 to all rLep d 2 mutants was observed. The mutant lacking all 3 disulfide bonds, rLep d 2.6Cys, demonstrated neither any IgE nor IgG4 reactivity. In contrast, IgG1 antibodies had a different reactivity pattern and were detected among most subjects irrespective of atopy, exposure to L. destructor or disulfide impairments in rLep d 2. Moreover, IgG1 levels to rLep d 2(wt) and rLep d 2.6Cys correlated (n = 60; rs = 0.65; p < 0.0001). CONCLUSIONS: IgE/IgG4 Ab to rLep d 2 were restricted to atopic farmers and demonstrated parallel recognition patterns of conformational epitopes. In contrast, IgG1 antibodies are ubiquitously found and mainly recognize sequential structures. The observed isotypic difference and interindividual variation in antibody specificities among atopic and nonatopic subjects imply careful investigation of hypoallergenic variants destined for immunotherapy.

Allergens↗
PubMed2001

Fewer allergic respiratory disorders among farmers' children in a closed birth cohort from Sweden.

The aim of this study was to investigate the prevalence of respiratory allergy, eczema and atopic sensitization in a closed birth cohort of Swedish schoolchildren, 7-8 yrs of age (n=707), of farmers and nonfarmers on the island of Gotland, in the Baltic Sea. All children were born and raised on the island. The survey comprised a questionnaire on atopic diseases and lifestyle factors. Atopic sensitization was assessed by the skin-prick test (SPT) with 15 standardized allergens. The risk ratio (RR) for ever having asthma and/or allergic rhinoconjunctivitis was significantly lower among children of farmers compared to children of nonfarmers (RR=0.38, confidence interval (CI) 95% 0.19-0.77). SPTs (test rate 92%) showed that 32% of the children had at least one positive test. Although the number of positive SPTs did not differ between the groups, there was a reduced risk among children of farmers for having both respiratory symptoms and sensitization to any International Study on Asthma and Allergy in Childhood allergen (RR=0.28, CI 95% 0.09-0.88). The present indicate that living in a farming population seems to protect against development of respiratory allergic disorders but not against allergic sensitization.

Agriculture↗
PubMed2000

A new method for collecting airborne allergens.

BACKGROUND: Measurement of airborne allergens has hitherto been done with the use of fixed-location pumps or personal air samplers. Our objective was to find out whether ionizers could be good tools for collecting airborne allergens. As a model we have used cat allergen (Fel d l). We have compared Fel d l levels collected by the ionizer at different time periods, as well as comparing Fel d l levels obtained with the ionizer with those of low- and high-volume pumps. METHODS: Dust samples from floors and air samples collected with ionizers and pumps, obtained in 31 homes with cat, 23 homes without cats, and 28 day-care centres, were analysed for cat allergen content (Fel d I) by ELISA. RESULTS: Fel d l was present in the reservoir in all homes with cats, ranging from 660 to 375,000 ng/g (GM 75,000) and in the air collected by the ionizer from 2.0 to 204 ng/24 h (GM 19.3). The allergen in homes without cat varied from < 55 to 1,800 ng/g (GM 166). Corresponding levels in air were found in two of these homes (2.3 and 7.3 ng/24 h). There was a correlation between the number of cats and the amount of airborne cat allergen (r: 0.47; P < 0.05). The levels in day-care centres were < 55 to 3,070 ng/g in dust (GM 360) and < 1.1 to 7.9 ng/24 h in the air (GM 1.6). We obtained a moderately strong correlation between air and dust samples in homes with cats (rs: 0.64; P< 0.001) and in day-care centres (rs: 0.49; P<0.05). We found that a collection period of 24 h is preferable for the ionizer. The intrahome reliability coefficient was nearly two times higher for the ionizer (r: 0.69) than the pump (r: 0.39). CONCLUSIONS: The ionizer seems to be a good tool for monitoring the environment. It is easy to use and silent and does not disturb the airflow in the room.

Air Ionization↗
PubMed2000

Skin prick test and serological analysis with recombinant group 2 allergens of the dust mites L. destructor and T. putrescentiae.

BACKGROUND: The dust mites Lepidoglyphus destructor and Tyrophagus putrescentiae are important sources of allergen in farming environments. The major allergens of the dust mites L. destructor and T. putrescentiae have been cloned and expressed as recombinant proteins. OBJECTIVE: To evaluate the use of recombinant group 2 allergens of L. destructor (rLep d 2) and T. putrescentiae (rTyr p 2) in skin prick test (SPT), and serological analysis in sensitized and non-sensitized farmers chronically exposed to dust mites. METHODS: Skin prick test with rLep d 2, rTyr p 2 and the corresponding commercial extracts was performed in 44 farmers sensitized to L. destructor and/or T. putrescentiae, and 38 control farmers. IgE and IgG subclass antibodies to the recombinant allergens were analysed by RAST and ELISA, respectively. RESULTS: Out of the 44 subjects positive in SPT to L. destructor and/or T. putrescentiae extract, 26 (59%) displayed a positive SPT to one or the other of the recombinant allergens, whereas 21 (48%) were positive to both. Significant correlations were registered between the sizes of the weals induced by rLep d 2 and rTyr p 2 and the corresponding RAST values (P < 0.001). A majority of subjects positive in SPT to the recombinant allergens had detectable IgG4 antibodies, and the levels were significantly higher in the dust mite sensitized group than in the controls (P < 0.05). No such differences were found in the IgG1 values (P > 0.05). The results obtained with rLep d 2 and rTyr p 2 correlated relatively well with each other with respect to SPT, RAST and IgG4, suggesting that the allergens have similar or shared IgE epitopes. All the control subjects had a negative SPT and RAST to rLep d 2 and rTyr p 2. CONCLUSION: Recombinant group 2 allergens from the dust mite L. destructor and T. putrescentiae represent useful tools for diagnosis of dust mite allergy.

Adult↗
PubMed1999

Skin test evaluation of genetically engineered hypoallergenic derivatives of the major birch pollen allergen, Bet v 1: results obtained with a mix of two recombinant Bet v 1 fragments and recombinant Bet v 1 trimer in a Swedish population before the birch pollen season.

BACKGROUND: More than 95% of birch pollen-allergic subjects react with the major birch pollen allergen, Bet v 1, and almost 60% of them are sensitized exclusively to this allergen. OBJECTIVE: The aim of this study was to compare the in vivo biologic activity of genetically engineered hypoallergenic derivatives of Bet v 1 (an equimolar mixture of 2 recombinant [r] Bet v 1 fragments and of rBet v 1 trimer) with that of rBet v 1 wild-type by skin prick and intradermal testing. METHODS: Birch pollen-allergic patients who had not received immunotherapy (n = 23), a group of allergic patients without birch pollen allergy (n = 12), and nonatopic persons (n = 8) from northern Europe (Sweden) underwent skin prick and intradermal testing with different concentrations of the recombinant allergens and commercial birch pollen extract before the birch pollen season. Immediate and late-phase reactions were recorded and allergen-specific IgE and IgG subclass responses were determined by CAP radioallergosorbent test and ELISA, respectively. RESULTS: Atopic persons without birch pollen allergy and nonatopic individuals did not have skin reactions to rBet v 1 wild-type and genetically engineered hypoallergenic derivatives. By intradermal testing, 8 of 23 and 13 of 23 birch pollen-allergic patients did not react with the highest concentration (1 microg/mL) of the rBet v 1 fragment mix and rBet v 1 trimer, respectively, compared with 1 with rBet v 1 wild type. Likewise, the highest concentration (100 microg/mL) of fragment mix or trimer failed to elicit a positive skin prick test in 18 of 23 and 15 of 23 patients in comparison with 0/23 with the monomer. No late reactions were observed. CONCLUSION: The recombinant hypoallergenic birch pollen allergens can probably be used for patient-tailored immunotherapy with a reduced risk to induce anaphylactic reactions.

Adolescent↗
PubMed1999

Influence of interaction of environmental risk factors and sensitization in young asthmatic children.

BACKGROUND: The increasing prevalence of asthma and allergy in many countries demands evaluation of potential risk factors to improve the possibility of prevention. OBJECTIVE: We studied the association between exposure to cat and dog allergen and allergic sensitization in young children with asthma and interactions with potential environmental risk factors. METHODS: One hundred eighty-nine young children with asthma were evaluated. IgE antibodies to cat and dog were analyzed. Questionnaires were filled in focusing on exposure to cats and dogs, environmental tobacco smoke (ETS), and signs of home dampness as indicated by window pane condensation (WPC) during the first years of life. House dust was analyzed for content of cat (Fel d 1) and dog (Can f 1) allergen. RESULTS: There was a strong association between the degree of reported exposure to cat and dog and the concentration of the respective allergens in floor dust. A dose-response relationship was found between cat exposure, measured as either reported degree of cat exposure or cat allergen levels in dust, and sensitization both to cat and dog. No such relationship was found between exposure and sensitization to dog. WPC increased the risk for sensitization to cat (odds ratio = 2.6, 95% confidence interval 1.2-5.8), whereas ETS strongly tended to do so both to cat and dog. Interaction was found between exposure to ETS, WPC, and high levels of cat allergen (>8 microg/g dust). The presence of all 3 risk factors revealed a multiplicative interaction with a high risk of sensitization to cat (odds ratio = 42.0, 95% confidence interval 3.7-472.8). CONCLUSIONS: Keeping cats indoors may be a health hazard for infants and young children at risk for development of asthma, particularly when they live in a damp house and their parents smoke.

Allergens↗
PubMed1999

Sensitization to allergens of house-dust mite in adults with atopic dermatitis in a cold temperature region.

BACKGROUND: An IgE-mediated contact reaction to airborne allergens has been suggested as one important pathogenetic mechanism in atopic dermatitis (AD). The house-dust mite (HDM) might be a common allergen involved. In Scandinavia, sensitization to HDM has been rare, probably because of the cold, dry climate. However, recent studies indicate high levels of domestic mites and HDM allergen in 15-20% of homes in central and northern Sweden. METHODS: To evaluate the importance of the HDM in patients with AD in the Stockholm region, we screened 81 adult Stockholm residents with AD, for the prevalence and degree of sensitization to the HDM, according to specific IgE (RAST), skin prick test (SPT), and atopy patch test (APT). We also assessed the HDM exposure in their homes and correlated the results with clinical history, severity of the dermatitis, and type of residence during childhood and today. RESULTS: The sensitization rate to HDM was high (56% according to RAST, 24% according to SPT, and 47% according to APT), and 20% of the patients were exposed to HDM allergens in their beds. Mite exposure seemed to aggravate the dermatitis in highly sensitized patients. CONCLUSIONS: The results indicate that we have to take the HDM into account when discussing aggravating factors in adult patients with AD in the Stockholm region.

Adolescent↗
PubMed1999

Risk factors associated with asthma and rhinoconjunctivitis among Swedish farmers.

BACKGROUND: Earlier studies have shown a high prevalence of respiratory symptoms in farming communities and that storage mites constitute important allergens. We examined risk factors associated with asthma and rhinoconjunctivitis among Swedish farmers. METHODS: A population of 1015 small-scale dairy farmers was part of an epidemiologic survey. After selection based on symptom reports in a questionnaire, 461 of the farmers attended a medical examination, which comprised SPT, RAST analyses, and lung-function measurements. Risk factors for sensitization to different allergens, and development of asthma and rhinoconjunctivitis were assessed by multiple logistic regression. RESULTS: The prevalence of atopy was 26.7% among the farmers. For both asthma and rhinoconjunctivitis, sensitization to mites (OR = 5.8 vs. OR = 3.8) and pollens (OR = 10.3 vs. OR=5.8) was a significant risk factor. There was a significant relationship between sensitization to mites and working time (OR = 5.2). Environmental tobacco smoke and exposure to different animal species at the farm did not appear to affect the risk of allergen sensitization or respiratory symptoms. Farmers smoked less than the general population, but they more frequently had reduced FEV1. CONCLUSIONS: Allergen sensitization, especially to mites and pollens, was significantly associated with asthma and rhinoconjunctivitis in a farming community. The results point to allergen avoidance as a major goal for the prevention of occupational respiratory diseases among the farming population.

Adolescent↗
PubMed1999

Exposure to an abundance of cat (Fel d 1) and dog (Can f 1) allergens in Swedish farming households.

BACKGROUND: Earlier studies have shown that farmers are to a low degree sensitized to animal allergens. We have measured the amount of cat (Fel d 1) and dog (Can f 1) in farm households and examined the relationship between exposure and sensitization to cat and dog allergens. METHODS: Dust samples from the homes of 403 farmers who had participated in an epidemiologic follow-up study on respiratory symptoms were analyzed for allergen content by two-site ELISA methods. RESULTS: Fel d 1 was detected in 99.5% of the farmers' households ranging from 0.055 to 1455 microg/g dust in mattresses (GM 13.2) and to 3775 microg/g dust in living-room carpets (GM 17.1). Can f 1 was detected in 90.6% of the households from 0.2 to 116 microg/g dust in mattresses (GM 2.0) and to 504 microg/g dust in carpets (GM 4.3). Homes with pets present had the highest levels of the allergens (P<0.001). A total of 8.4% and 7.4% of the farmers were sensitized to cat and dog, respectively. A significant correlation was noted between exposure to the allergens and specific IgE to cat and dog, respectively (P<0.001). Sensitization to cat (OR = 4.9) and dog (OR = 17.8) was significantly associated with asthma. CONCLUSIONS: In spite of the abundance of Fel d 1 and Can f 1, farmers are only to a low degree sensitized to cats and dogs.

Agricultural Workers' Diseases↗
PubMed1999

Markers of inflammation and bronchial reactivity in children with asthma, exposed to animal dander in school dust.

Several studies have confirmed the presence of animal dander allergens in school dust but the effect of this indirect animal exposure on health has not been evaluated. In this study we investigated bronchial reactivity and markers of eosinophil activity and inflammation during two separate weeks of school in 10 children with mild asthma and a positive skin prick test to cat and dog. At the beginning and the end of the first week the children underwent bronchial challenges with methacholine, and at the beginning and the end of the second week they underwent nasal lavages (NAL) and induced sputum samplings. Blood and urine samples for analysis of inflammatory markers were obtained before and after both school weeks. Peak expiratory flow (PEF) and symptoms of asthma and allergy were recorded daily, and spirometry was performed on each visit. The exposure to animal dander allergens was estimated from dust samples obtained in the subjects' schools and homes. Bronchial sensitivity to methacholine increased in the week when this was measured. The proportion of eosinophils in peripheral blood, and urinary eosinophil protein X (EPX), decreased in both weeks. There was a trend towards an increase of eosinophil peroxidase (EPO) and myeloperoxidase (MPO) in sputum in the week when these proteins were measured. The concentrations of cat (Fel d1) and dog (Can f1) allergens were higher in dust collected in schools than in homes. Our results show that in children with mild asthma and animal dander allergy, there is a significantly increased bronchial sensitivity to methacholine after one school week. There is also a significant decrease in the number of circulating eosinophils and a trend towards an increase of sputum EPO, which could correlate with the early phase of eosinophil recruitment to the lungs. These effects may be related to the continuous exposure to animal allergens in school dust.

Adolescent↗