Now, Dr. Blumberg and a team have what they say is the first biological evidence to link early exposure to germs to stronger adult immune systems. They say this exposure could prevent the development of some autoimmune diseases.
In the adult germ-free mice, they found that inflammation in the lungs and colon was caused by so-called killer T cells. These normally fight infection. But they became overactive and targeted healthy tissue -- an autoimmune condition seen in asthma and a disease called ulcerative colitis.
Dr. Blumberg says the mice raised in a normal environment did not have the same reaction. He says their immune systems had been "educated" by early exposure to germs.
RICHARD BLUMBERG: "What was really most remarkable to us was the fact that once the education event provided by the microbes occurred in early life, it was durable and lasted throughout the life of the animal."
Rates of autoimmune disorders are rising worldwide, but mostly in wealthier, industrialized countries.
RICHARD BLUMBERG: "I think one obvious question, for example, that’s raised by these studies is the early life use of antibiotics and whether we need to be more careful in their prescribing."
Rob Dunn is a professor of ecology and evolutionary biology at North Carolina State University in Raleigh. He says the new study does not mean people should stop washing.
ROB DUNN: "Wash your hands, but don't do it with antimicrobial soap. Let your kids play in a reasonable amount of dirt and get outside and get exposed to a diversity of things."
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2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25