Being born on a farm MAY prevent contact allergies
Being born and raised on a farm may prevent allergies, but the underlying immunological mechanisms are still poorly understood. Swiss researchers pursued this idea by comparing groups of mice to whose skin they applied allergenic substances. Some were born and raised on a farm, the others in the laboratory (some of which were transferred to the farm). Then they studied the immunological changes involved in preventing allergies, as well as their intestinal microbiota.
Unsurprisingly, mice born on the farm showed a reduced tendency to develop contact allergies compared with those raised in the laboratory. When they were moved to the farm, that tendency was reduced the earlier the environmental change happened in their life. The immune systems of the farm mice were activated earlier and secreted more IL22, a molecule that modulates the allergic response. Furthermore, their microbiota was enriched with age, containing more bacteria with immune modulating properties. These results confirm that the farm is an environment that protects against contact allergies, say the authors.
C. P. Frossard et al. The farming environment protects mice from allergen-induced skin contact hypersensitivity. Clinical & Experimental Allergy, 47, 805-814. http://onlinelibrary.wiley.com/doi/10.1111/cea.12905/epdf