Pregnant women, who are exposed to farms, particularly to barns and farm milk, protect their newborns from developing allergies, says a new study.
Researchers in Germany recently studied 18 farming mothers and 59 non-farming mothers and discovered that exposure to farms affects a baby's T regulatory cells.
These cells are now believed to suppress immune responses, thus maintaining immune system homeostasis and contributing to healthy immune development.
"We found that the babies of mothers exposed to farms have more and better functioning regulatory T cells," explained Bianca Schaub, M.D., who led the research team at University Children's Hospital in Munich.
"The effect was strongest among those mothers who entered barns or drank farm milk," she added.
Dr. Schaub and her researchers believe that the findings represent "a potential immunological explanation of the mechanism" that produces "the protective farm effect" on the development of childhood atopic diseases.
To conduct this study, the investigators assessed exposure through detailed questionnaires. They then recorded the number of regulatory T cells (CD4+CD25+ high, Foxp3+) and their associated genes (Foxp3/LAG3) after stimulating cord blood mononuclear cells with microbial stimuli and allergens.
Expression of the regulatory T cells and associated genes were significantly higher in the blood drawn from the umbilical cord of babies whose moms spent time on a farm.
According to Dr. Schaub, the findings support the "paradigm shift" from attributing allergic diseases solely to an impaired balance between anti-allergic Th1 cells and pro-allergic Th2 cells.
"It may be possible that T regulatory cells are capable of preventing an allergic response at an early time point by suppressing Th2 cells," she said.
"It is a long way off, but these findings may one day hopefully help researchers to develop an effective preventive strategy, perhaps even a vaccine, against allergic diseases," she added.
The study will be presented at the American Thoracic Society's 2008 International Conference in Toronto.