Abstract
Background: Our previous studies suggested a protection against allergic diseases through farm exposure. The underlying mechanisms may involve immune regulation through T cell subsets already present early in childhood.
Objective: To assess whether T regulatory cells (Tregs) are involved in the allergy-protective effect of farm exposure in childhood and which specific exposures are relevant.
Methods: 457 pregnant women were recruited before delivery and followed until the age of 4.5 years in Germany (n=254) and France (n=203) as part of a European birth cohort study (PASTURE/EFRAIM). Children of families living on livestock farms were compared to children of families from this region, but not living on farms. Detailed questionnaires assessed farming exposures over time. Tregs (CD4+CD25highFOXP3+ expression) in peripheral blood mononuclear cells (PBMC) were assessed at 4.5 years before and following stimulation (lipopolysaccharide (LPS), PMA/Ionomycin (PI)) by flow cytometry.
Results: At 4.5 years of age, farm-exposed children showed increased Tregs following stimulation (LPS, PI), p<0.05). Specifically, exposure to farm milk was strongly associated with increased Tregs upon LPS and PI-stimulation (p≤0.001). Exposure to stable was associated with increased Tregs after LPS and PI-stimulation (p=0.006, p=0.02; respectively).
Conclusions: Farm exposure, and particularly farm milk intake in early childhood, was associated with an increase of Tregs in early childhood upon specific stimulation. Specific contents of farm milk may modulate the immune system towards a regulatory profile potentially leading to a protective effect for the development of childhood allergic diseases.
- © 2011 ERS