Background: Enhanced eosinophil/basophil (Eo/B) progenitor levels are known to contribute to allergic inflammation and associated with atopic risk. So far, less data exist about the responsiveness of Eo/B progenitor cells to environmental pollutants. Therefore, the aim of the present study was to investigate the influence of different indoor exposures on the recruitment and differentiation of Eo/B progenitors in mother-child pairs.
Method: Analyses of Eo/B progenitors were performed in a sub cohort of 68 mother-child-pairs at children's age of two within the LINA cohort study (Lifestyle and environmental factors and their Influence on Newborns Allergy risk). PBMCs were used for methylcellulose assays to assess colony formation (CFU) in presence of IL-3, IL-5 or GM-CSF. Standardized questionnaires answered by parents were used to collect information about atopic outcomes and indoor exposures to tobacco smoke as well as disinfectants during the second year of life. Concentrations of volatile organic compounds (VOC) were measured around the first birthday in the home.
Result: A positive correlation was found between maternal and infantile circulating IL-3 (p<0.001) and GM-CSF (p<0.05) stimulated Eo/B CFUs at children's age of two. In children, increased numbers of IL-3, IL-5 or GM-CSF stimulated Eo/B CFUs were seen in response to indoor VOC exposures, tobacco smoke and usage of disinfectants. In contrast, maternal Eo/B CFUs were not significantly affected by most of these exposures. Further, children's enhanced numbers of IL-3 and GM-CSF stimulated Eo/B CFUs, raw or adjusted for known confounders, were associated with treated wheezing during the second year of life (p<0.05).
Conclusion: This study demonstrates that the recruitment and differentiation of Eo/B progenitors in infants is much more sensitive to indoor air pollutants compared to their corresponding mothers. Resulting enhanced numbers of Eo/B CFUs may contribute to the development of respiratory diseases in early infancy.