PLoS ONE / Exposure to indoor allergens in different residential settings and its influence on IgE sensitization in a geographically confined Austrian cohort

Background Exposure to indoor allergens is crucial for IgE sensitization and development of allergic symptoms. Residential settings influence the allergen amount in house dust and hence allergic sensitization. Within this study, we investigated allergen exposure and molecule-based IgE levels in a geographically confined region and evaluated the impact of housing, pets and cleaning. Methods 501 adolescents from Salzburg, Austria participated in this cross-sectional study. House dust samples were examined regarding major mite, cat, dog, and mold allergens using a multiplex assay. Serum samples of participants were analyzed for specific IgE to Der p 1, Der p 2, Fel d 1, Can f 1 and Alt a 1 using the multiplex array ImmunoCAP ISAC. Information on allergies, living areas, dwelling form (house, flat, farm), pets, and household cleanliness were obtained by a questionnaire. Results In investigated house dust samples, the concentration of cat allergen was highest while the prevalence of mold allergens was very low. Participants showed IgE sensitization to Der p 1 (13.2%), Der p 2 (18.2%), Fel d 1 (14.4%), Can f 1 (2.4%) and Alt a 1 (2.0%). In alpine regions, lower mite allergen concentrations were detected which correlated with reduced IgE levels. A trend for increased sensitization prevalence from rural to alpine to urban regions was noted. Living on farms resulted in lower sensitization prevalence to mite and cat allergens, even though exposure to mites was significantly elevated. The presence of cats was associated with a lower sensitization rate and IgE levels to cat and mite allergens, and less frequent allergic diseases. Cleaning did not impact allergen concentrations, while IgE reactivity to mites and allergic diseases were more pronounced when living in cleaner homes. Conclusion Allergen exposure to indoor allergens was influenced by setting of homes. Living in a farm environment and having a cat at home showed a pro tective effect for IgE sensitization and allergies. This cross-sectional study in combination with hereditary and lifestyle factors enables development of risk schemes for a more efficient management and potential prevention of allergic diseases

Exposure to Indoor Allergens in Different Residential Settings and Its Influence on IgE Sensitization in a Geographically Confined Austrian Cohort.

Exposure to indoor allergens is crucial for IgE sensitization and development of allergic symptoms. Residential settings influence the allergen amount in house dust and hence allergic sensitization. Within this study, we investigated allergen exposure and molecule-based IgE levels in a geographically confined region and evaluated the impact of housing, pets and cleaning.501 adolescents from Salzburg, Austria participated in this cross-sectional study. House dust samples were examined regarding major mite, cat, dog, and mold allergens using a multiplex assay. Serum samples of participants were analyzed for specific IgE to Der p 1, Der p 2, Fel d 1, Can f 1 and Alt a 1 using the multiplex array ImmunoCAP ISAC. Information on allergies, living areas, dwelling form (house, flat, farm), pets, and household cleanliness were obtained by a questionnaire.In investigated house dust samples, the concentration of cat allergen was highest while the prevalence of mold allergens was very low. Participants showed IgE sensitization to Der p 1 (13.2%), Der p 2 (18.2%), Fel d 1 (14.4%), Can f 1 (2.4%) and Alt a 1 (2.0%). In alpine regions, lower mite allergen concentrations were detected which correlated with reduced IgE levels. A trend for increased sensitization prevalence from rural to alpine to urban regions was noted. Living on farms resulted in lower sensitization prevalence to mite and cat allergens, even though exposure to mites was significantly elevated. The presence of cats was associated with a lower sensitization rate and IgE levels to cat and mite allergens, and less frequent allergic diseases. Cleaning did not impact allergen concentrations, while IgE reactivity to mites and allergic diseases were more pronounced when living in cleaner homes.Allergen exposure to indoor allergens was influenced by setting of homes. Living in a farm environment and having a cat at home showed a protective effect for IgE sensitization and allergies. This cross-sectional study in combination with hereditary and lifestyle factors enables development of risk schemes for a more efficient management and potential prevention of allergic diseases

Study enrollment.

<p>Study enrollment.</p

Allergen concentrations in house dust samples collected in households with and without pets.

<p><b>(A)</b> Allergen concentrations in homes with and without a pet. <b>(B)</b> Allergen concentrations in homes with and without a cat. <b>(C)</b> Allergen concentrations in homes with and without a dog. Boxes indicate 25^th to 75^th percentile, horizontal line represents median, whiskers indicate 5^th and 95^th percentiles. *, p<0.05; ****, p<0.0001 for pairwise comparisons.</p

Demographic data of participants.

<p>Demographic data of participants.</p

Allergen concentrations in house dust samples collected in different housing settings.

<p><b>(A)</b> Allergen concentrations in different living areas (urban, rural and alpine). <b>(B)</b> Allergen concentrations in different dwelling forms (flat, house and farm). Boxes indicate 25^th to 75^th percentile, horizontal line represents median, whiskers indicate 5^th and 95^th percentiles. *, p<0.05; ***, p<0.001; ****, p<0.0001 for pairwise comparisons.</p

Dot plot of the specific IgE levels to indoor allergens and respective sensitization rates.

<p>Dots represent individual measurements, lines indicate mean values and whiskers the standard deviation.</p

IgE levels to indoor allergens of participants with or without pets at home.

<p><b>(A)</b> IgE levels of participants with or without any pet at home. <b>(B)</b> IgE levels of participants with or without a cat at home. <b>(C)</b> IgE levels of participants with or without a dog at home. Dots represent individual measurements, lines indicate mean values and whiskers the standard deviation. *, p<0.05; **, p<0.01.</p

IgE levels to indoor allergens in sera of pupils living in different settings.

<p><b>(A)</b> IgE levels of pupils living in different areas (urban, rural, alpine). <b>(B)</b> IgE levels of pupils living in different dwelling forms (flat, house, farm). Dots represent individual measurements, lines indicate mean values and whiskers the standard deviation. *, p<0.05; **, p<0.01; ****, p<0.0001.</p

Allergen concentrations found in investigated house dust samples and respective detection rates.

<p>Boxes indicate 25^th to 75^th percentile, horizontal line represents median, whiskers indicate 5^th and 95^th percentiles.</p