The LINA cohort: indoor chemical exposure, circulating eosinophil/basophil ( Eo/ B) progenitors and early life skin manifestations.

Background Hematopoietic progenitor cells, especially those committed to the Eo/ B lineage, are known to contribute to allergic inflammation. Objective The aim of the present study was to investigate whether environmental factors are associated with changes in numbers of circulating Eo/ B progenitors at 1 year of age. Methods Peripheral blood from 60 1-year-old children enrolled in the LINA (Lifestyle and environmental factors and their Influence on Newborns Allergy risk) birth cohort was assessed for Eo/ B progenitor cells ( Eo/ B CFU) using standardized and validated methylcellulose assays. Frozen peripheral blood mononuclear cells ( PBMC) were cultured in the presence of IL-3, IL-5 or GM- CSF, and Eo/ B CFUs enumerated. Clinical outcomes and exposure to environmental tobacco smoke ( ETS) were documented by standardized questionnaires, and indoor volatile organic compound ( VOC) concentrations were assessed by passive sampling. Results Children with skin manifestations (atopic dermatitis or cradle cap) within the first year of life had higher numbers of circulating IL-3-, IL-5- or GM- CSF-stimulated Eo/ B CFUs ( P < 0.05) at 1 year. In children with cradle cap, a positive correlation was found between Eo/ B CFUs and exposure to ETS-related VOCs during pregnancy or at 1 year of age ( P < 0.05). Conclusions and Clinical Relevance This is the first demonstration that environmental exposures are positively associated with levels of circulating Eo/ B progenitors. The recruitment and differentiation of Eo/ B progenitors in response to environmental triggers may play a role in the development of skin manifestations during the first year of life. [ABSTRACT FROM AUTHOR]