Twin study shows microbes and other factors lead the immune system to adapt
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Environmental factors shape the immune system’s reactions more than genes do, a study of twins suggests. As people age, the effect of the environment on their immune systems grows even stronger, researchers report January 15 in Cell.
In the study, 58 percent of the variation measured in immune system responses was almost completely determined by nonheritable factors, such as exposure to microbes such as cytomegalovirus, a mostly benign virus that lives in 50 to 80 percent of adults.
The findings reinforce evidence that microbes have a powerful influence on the development of the human immune system. The lessons learned from this study also may lead to a better understanding of how genes and the environment interact, helping researchers figure out why some people get asthma, allergies or other autoimmune diseases, while others develop healthy immune reactions.
“It’s not negating