Within the Clinical Research Unit 339 Food@, the impact of the exposome on the development and tolerance induction of allergies is being studied. A central component is the analysis of allergen exposure in the domestic environment. Dog ownership may play a potentially significant role in immunomodulation. Therefore, this study investigated the concentration of the major dog allergen Can f 1 in house dust samples to analyze its association with dog contact and other clinical data. This investigation is part of the study "Tolerance Induction through Non-Avoidance to Prevent Persistent Food Allergy".  

Since 2021, living room and bed dust samples have been collected from food allergic participants of a clinical cohort (children and adults). The dust samples were collected using a specialized vacuum cleaner adapter, stored at −20 °C, and subsequently extracted using standardized protocols. The concentration of Can f 1 was determined using a standardized Enzyme-Linked Immunosorbent Assay. Statistical analysis was performed descriptively, as well as using the Mann-Whitney-U test and Spearman correlations in SPSS. 

Overall, both children and adults (n=145) showed significantly higher Can f 1 concentrations (p < 0.001) in households with dogs (125.67 ng/ml, n=12) compared to households without dogs (68.25 ng/ml, n=133). Similar results were observed for bed dust samples (households with dogs: 111.42 ng/ml; without dogs: 62.60 ng/ml; p < 0.001, n=133). Additionally, in children, a significant but weak positive correlation (r = 0.215; p = 0.030) was found between the Can f 1 concentration in the living room and the maximum tolerated dose in the oral food challenge (OFC). This correlation was not observed in adults.

The results suggest that dog ownership significantly increases Can f 1 allergen levels in the domestic environment. The observed correlation between Can f 1 concentrations and the maximum tolerated dose in the OFC among children indicates that allergen exposure may have a potentially positive immunomodulatory effect during childhood. However, due to the small number of dog-owning participants, further studies are needed to better understand the role of dog ownership in tolerance development. 

This study is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) as part of the clinical research unit (CRU339): Food allergy and tolerance (FOOD@) – 409525714.