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Variability of house dust mite allergen exposure in dwellings
T Hirsch1, E Kuhlisch, W Soldan
1Children's Clinic, University Hospital, Dresden, Germany.
Abstract:
The variability of repeated house dust mite (HDM) allergen determinations at the same site within 3-24 months was evaluated on previously collected samples. Between two and four repeated measurements of Der p 1, a major allergen of Dermatophagoides pteronyssinus and Der f 1, a major allergen of D. farinae, on 46 carpets and 31 mattresses were analyzed. In 90% of carpets and mattresses, HDM allergen concentrations were clinically relevant (at least one measurement >0.1 microg Der p 1 + Der f 1/g dust). The coefficients of variation (CVs) for allergen concentrations in repeated samples over time (55.3-82.0% for the two allergens in beds and carpets) were clearly greater than the CVs for multiple samples collected at the same time (4.0-32.6%). Determination of allergen mass per square meter of surface instead of concentration per gram of dust resulted in an even greater CV (72.3-86.7%). The 95% range of expected values was about 10-fold above and below the result of a single determination. We conclude that single determinations of HDM allergen in dust give very limited information about long-term exposure of an individual to the allergen. Repeated measurements are recommended. Studies of factors that affect HDM allergen exposure must be planned with appropriate sample sizes.
Insights
Repeated house dust mite (HDM) allergen tests show high variability over time. Single HDM allergen measurements provide limited insight into long-term exposure, necessitating repeated testing for accurate assessment.
Area of Science:
- Allergen immunotherapy
- Environmental health
- Clinical immunology
Background:
- House dust mites (HDM) are a major source of indoor allergens.
- Exposure to HDM allergens is linked to asthma and allergic diseases.
- Accurate assessment of HDM allergen exposure is crucial for effective management.
Purpose of the Study:
- To evaluate the variability of repeated house dust mite (HDM) allergen determinations over time.
- To assess the reliability of single allergen measurements for long-term exposure assessment.
- To inform the design of studies investigating HDM allergen exposure.
Main Methods:
- Analysis of repeated measurements (2-4) of Der p 1 and Der f 1 allergens.
- Samples collected from 46 carpets and 31 mattresses over 3-24 months.
- Calculation of coefficients of variation (CVs) for allergen concentrations and mass per surface area.
Main Results:
- High variability in HDM allergen levels was observed in repeated samples over time (CVs 55.3-82.0%).
- Variability was significantly greater over time compared to simultaneous sampling (CVs 4.0-32.6%).
- Determination of allergen mass per square meter showed even higher variability (CVs 72.3-86.7%).
Conclusions:
- Single HDM allergen determinations offer very limited information on long-term exposure.
- Repeated measurements are recommended for a more accurate assessment of HDM allergen exposure.
- Future studies require appropriate sample sizes to account for high allergen variability.