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14-01-2010 | Respiratory | Article

Prenatal farm exposure influences immune system development

Abstract

Free abstract

MedWire News: Maternal exposure to farming activities during pregnancy modulates early immune system responses in neonates, research suggests.

The findings support the results of previous studies, which indicate that living in a farming environment is protective against the development of asthma and allergies, and suggest that such a protective effect can be initiated prenatally through programming of the innate and adaptive immune system.

Harald Renz (Philipps-University of Marburg, Germany) and team analyzed data from the PASTURE (Protection Against Allergy – Study in Rural Environments) study on 299 children born to mothers who lived on farms during pregnancy and 326 born to women who were not exposed to a farming environment.

Cord blood from both groups was collected at delivery and analyzed for the production of cytokines, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-5, IL-10, and IL-12.

The researchers found that TNF-α was more often detectable in cord blood from children born to farming families than in nonfarm children, at an odds ratio of 1.52.

Quantitative analysis also revealed significantly higher levels of IFN-γ in cord blood from children born to farming families than those born to nonfarming families, although levels of TNF-α were nonsignificantly higher in cord blood from farm children.

There were no significant differences in cord blood levels of IL-5, IL-10, or IL-12 between the two groups of children.

Further analysis of data from the PASTURE study revealed that maternal contact with a variety of farm animal species and consumption of farm-produced butter during pregnancy enhanced the production of proinflammatory cord blood cytokines, whereas maternal consumption of farm-produced yogurt resulted in significantly lower levels of IFN-γ and TNF-α in cord blood.

Renz and team conclude in the Journal of Allergy and Clinical Immunology: “Maternal farming lifestyle in close contact with livestock and self-produced dairy products seems to induce mechanisms in the progeny that result in a T-helper 1-skewed cytokine pattern at birth.

“This new finding might represent the initial step for allergy protection later in life.”

They add: “The follow-up of the PASTURE cohort will allow the verification of this notion once children attain school age, when clinical allergic outcomes will have become apparent.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Mark Cowen

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