Innate immunity and asthma risk in Amish and Hutterite farm children
Exposure to an environment rich in microorganisms can protect against asthma
This study examined environmental exposures and immune profiles of sixty children from two different U.S. farming communities — Amish and Hutterite. While these two groups have similar ancestry and lifestyles, they have different farming practices and their prevalence of asthma differs. The Amish practice traditional farming, live on single family dairy farms, and use horses for fieldwork and transportation. The Hutterites, on the other hand, live on large, highly industrialized, communal farms. Previous studies have demonstrated that the prevalence of asthma for the Amish is 5.2% vs. 21.3% for the Hutterite. Previous studies revealed remarkable genetic similarities between the Amish and Hutterite children, as compared with other European populations.
Participating in this study were 30 Amish children (7-14 years of age) who lived in Indiana and thirty Hutterite children who lived in South Dakota and were matched with the Amish children for sex and for age within 1 year. One parent of each child responded to a questionnaire on their child’s symptoms and previous diagnoses of asthma.
Environmental measurement of levels of allergens and endotoxins and the microbiome composition of indoor dust samples were taken in both the Amish and Hutterite homes. Results showed that the endotoxin levels were 6.8 times higher in the Amish homes than in the Hutterite homes; similar differences were found in the composition of bacteria in mattress dust. These findings suggest that Amish children are exposed to higher levels of microbial elements in their home. Data from blood samples revealed profound differences in the innate immune cells of the two groups of children in that crucial immune pathways were activated in the Amish but not in the Huttrerite children.
An experimental allergic asthma test was then conducted on mice. The intranasal instillation of dust extracts from Amish but not Hutterite homes significantly inhibited airway hyper-reactivity and conditions related to asthma. This indicates that house dust from Amish homes provided robust protection against the development of experimental asthma.
The results of this study involving both humans and mice indicate that the Amish farming environment provides protection against asthma by engaging and shaping the innate immune response. These findings also support the idea that exposure to an environment rich in microorganisms can protect against asthma.
Stein, M.M., Hrusch, C.L., Gozdz, J., Igartua, C., Pivniouk, V., Murray, S.E., Ledford, J.G., Marques dos Santos, M., Anderson, R.L., Metwali, N., Neilson, J.W., Maier, R.M., Gilbert, J.A., Holbreich, M., Thorne, P.S., (2016). Innate immunity and asthma risk in Amish and Hutterite farm children. New England Journal of Medicine, 375(5),