In a recent study by Heidi Kääriö et al., using samples from the Protection Against Allergy-Study in Rural Environments (PASTURE) birth cohort, demonstrate that farm exposures (stables, hay barn, farm milk) at age 4.5 years is linked to amplified Th1-type cytokine production.
The research group from Finland and Germany report that peripheral blood mononuclear cells (PBMCs) from farm children produced more Th1-associated cytokines such as IL-12 and interferon (IFN)-γ, and immunoregulatory cytokines such as IL-10. Interestingly, the number of farm exposures correlated with higher IFN-γ levels.
Children growing up on a farm have significantly less asthma, hay fever and atopic reactions. Farm exposure provides protection from childhood asthma and allergic diseases, but the causal mechanisms remain poorly understood.
It is also known that T helper (Th) 2-type cytokines such as interleukin (IL)-4, IL-5 and IL-13 drive allergic/asthma reactions, whereas Th1-type cytokines antagonize these effects.
Thus, growing up on a farm, in early childhood, and its related Th1-type immune responses may be linked to suppressed, allergy related Th2-type responses, and this may provide help explaining the protection of farming lifestyle on asthma and allergy development in children.