The environment of a child in the first two years of birth could influence the inherited risk of developing eczema, suggests research, proximity to dogs particularly decreasing the strength of a genetic variant.
The results, published in AllergySuggest that although people can be genetically predisposed to the dry and inflamed skin state, exposure to certain environmental factors can increase or decrease this risk.
Overall, seven factors, including the use of antibiotics and the older brother, have shown an interaction with genes predisposing to eczema, exposure to dogs being particularly powerful.
The study is the most important and complete analysis to date by studying the interaction between genes and the environment in atopic eczema, say investigators.
Sara Brown researcher, PHD, of the University of Edinburgh, said that the study was aimed at answering some of the most difficult questions asked at the clinic by caregivers, such as why a child had eczema and what could be done to help protect her baby.
“We know that the genetic composition affects the risk of a child to develop eczema and previous studies have shown that the possession of a company dog can be protective, but this is the first study to show how it can happen at the molecular level,” she continued.
“More work is necessary, but our results mean that we have a chance to intervene in the rise of allergic diseases, to protect future generations.”
Atopic eczema, also known as atopic dermatitis, is a chronic inflammatory disease and a systemic condition affecting approximately one in five and one in ten adults living in high -income countries.
Although it is a hereditary line, its rapid increase in prevalence in the past 30 years in industrialized areas demonstrates the importance of environmental factors in its etiology.
Brown and his colleagues used 16 studies to explore the interactions between 24 most important risks that have been associated with atopic eczema in association studies across genome and 18 environmental factors at the start of life.
Environmental exhibitions to early life composed of those in utero and during the first 2 years of life were included to minimize reverse causality.
The team then tested the gene-environment interactions in 10 additional studies on European populations and carried out in vitro Modeling using a model of skin keratinocytes to validate the identified interactions.
The initial analysis involved 25,339 people, suggesting evidence of interaction between at least one genetic variant established for eczema and seven environmental factors: the use of antibiotics; possession of cats; Dog property; breast-feeding; older brother; smoking; and washing practices and at least a genetic variant established for eczema. In all, there were 14 interactions.
The following analysis of 254,532 people showed that exposure to dogs interacted with the RS10214237 variant on chromosome 5 and was correlated with the expression of the interleukin-7 receptor, which is a protein involved in the function of immune cells.
A more in-depth survey revealed that canine proximity has had an impact on this genetic variant on eczema, providing a protective effect via the interleukin-7 receiver gene, and perhaps also interleukin-10, suppressing skin inflammation.
The authors add: “There may be an interaction effect equivalent to the brothers and sisters, but this is not possible to model in vitro. “”
They suggest that the effect of other interactions could be low and may be unlikely to have important contributions to the pathogenesis of eczema.