Prenatal farm exposure is related to the expression of receptors of the innate immunity and to atopic sensitization in school-age children
ABSTRACT There is increasing evidence that environmental exposures determining childhood illnesses operate early in life. Prenatal exposure to a farming environment through the mother might also play an important role.
We sought to investigate the role of maternal exposures to environments rich in microbial compounds for the development of atopic sensitization, asthma, and corresponding alterations in the innate immune system in offspring.
In the children of the cross-sectional Prevention of Allergy Risk Factors for Sensitization in Children Related to Farming and Anthroposophic Life Style study, asthma and atopy were assessed by means of standardized questionnaires (n = 8263) and serum IgE measurements (n = 2086). In a subsample (n = 322) gene expression of Toll-like receptors (TLR2 and TLR4) and CD14 was assessed. Maternal exposures were defined through questionnaire information.
Both atopic sensitization (adjusted odds ratio, 0.58; 95% CI, 0.39-0.86) and the gene expression of receptors of innate immunity were strongly determined by maternal exposure to stables during pregnancy, whereas current exposures had much weaker or no effects. A dose-response relation was found between the extent of upregulation of these genes and the number of different farm animal species the mother had encountered in her pregnancy. Each additional farm animal species increased the expression of TLR2, TLR4, and CD14 by a factor of 1.16 (95% CI, 1.07-1.26), 1.12 (95% CI, 1.04-1.2), and 1.10 (95% CI, 1.03-1.23), respectively.
Maternal exposure to an environment rich in microbial compounds might protect against the development of atopic sensitization and lead to upregulation of receptors of the innate immune system. The underlying mechanisms potentially operating through the intrauterine milieu or epigenetic inheritance await further elucidation.
When assessing risk factors of allergies in an infant's medical history, attention must also be paid to environmental exposures affecting the mother.
Full-textDOI: · Available from: Christian Bieli, Mar 18, 2015
- SourceAvailable from: Mimi L K Tang
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- "September 2012 | Volume 3 | Article 171 | 1 Toh et al. Probiotic therapy for allergic disease or asthma (Riedler et al., 2001), while prenatal farm exposure modulates atopic sensitization later in life (Ege et al., 2006). The human intestinal microbiota represents the most significant microbial exposure for the developing infant. "
ABSTRACT: The prevalence of allergic disease has increased dramatically in Western countries over the past few decades. The hygiene hypothesis, whereby reduced exposure to microbial stimuli in early life programs the immune system toward a Th2-type allergic response, is suggested to be a major mechanism to explain this phenomenon in developed populations. Such microbial exposures are recognized to be critical regulators of intestinal microbiota development. Furthermore, intestinal microbiota has an important role in signaling to the developing mucosal immune system. Intestinal dysbiosis has been shown to precede the onset of clinical allergy, possibly through altered immune regulation. Existing treatments for allergic diseases such as eczema, asthma, and food allergy are limited and so the focus has been to identify alternative treatment or preventive strategies. Over the past 10 years, a number of clinical studies have investigated the potential of probiotic bacteria to ameliorate the pathological features of allergic disease. This novel approach has stemmed from numerous data reporting the pleiotropic effects of probiotics that include immunomodulation, restoration of intestinal dysbiosis as well as maintaining epithelial barrier integrity. In this mini-review, the emerging role of probiotics in the prevention and/or treatment of allergic disease are discussed with a focus on the evidence from animal and human studies.Frontiers in Pharmacology 09/2012; 3:171. DOI:10.3389/fphar.2012.00171 · 3.80 Impact Factor
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- "Robust epidemiological data linking early environmental exposures to the development of allergies have been obtained in studies of European children born to farming and non-farming families, which show that farmer's children develop less atopy or asthma (Braun-Fahrlander et al. 1999; Riedler et al. 2000; Von Ehrenstein et al. 2000). The maternal exposure to stables and farm animals during pregnancy , was strongly associated with up-regulation of innate immune receptors and lower degree of allergic sensitization in a child born to a farmer mother (Ege et al. 2006). In terms of cytokines, maternal exposure to microbial compounds and consumption of farm dairy products was associated with increased T helper 1 (Th1)-type (IFN-γ) and pro-inflammatory (TNF-α) cytokines in cord blood (Pfefferle et al. 2010). "
ABSTRACT: The shaping of a child's immune system starts in utero, with possible long-term consequences in later life. This review highlights the studies conducted on the development of the immune system in early childhood up to school-age, discussing the impact that environmental factors may have. Emphasis has been put on studies conducted in geographical regions where exposure to micro-organisms and parasites are particularly high, and the effect that maternal exposures to these may have on an infant's immune responses to third-party antigens. In this respect we discuss the effect on responses to vaccines, co-infections and on the development of allergic disorders. In addition, studies of the impact that such environmental factors may have on slightly older (school) children are highlighted emphasizing the need for large studies in low to middle income countries, that are sufficiently powered and have longitudinal follow-up components to understand the immunological footprint of a child and the consequences throughout life.Parasitology 07/2011; 138(12):1508-18. DOI:10.1017/S0031182011000588 · 2.35 Impact Factor
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- "In a parallel study, 5-13-yr-old children of farm-exposed mothers displayed reduced rates of sensitization and concomitantly increased TLR2, TLR4, and CD14 gene expression in PBMCs (Ege et al., 2006). It should be emphasized that the effects in the children were unrelated to the farm exposure levels at the time of their PBMC collection , and instead were related exclusively to the mothers' exposures during pregnancy. "
ABSTRACT: The progressive rise in the prevalence of allergic diseases since the 1970s is widely attributed to diminished exposure to microbial stimuli, resulting in dysregulated immune functions during early life. Most studies investigating the mechanism behind this phenomenon have focused on postnatal microbial exposure. But emerging evidence suggests that such programming may also occur in the developing fetus as a result of microbial stimulation of the pregnant mother.Journal of Experimental Medicine 12/2009; 206(13):2861-4. DOI:10.1084/jem.20092469 · 13.91 Impact Factor