Studies have shown that the incidence of autoimmune disease tends to be highest in the developed world, and is highest there among upper-income groups. Weinstock (from the University of Iowa) and others hypothesize that the elimination of certain intestinal parasites may have led to the loss in some individuals of a key mechanism for modulating the immune system.
Millions of organisms, including viruses, bacteria and worms, enter
the body through contact with dirt. Researchers believe many of these
organisms are needed to train the body's immune system to recognize and
"Microbes have adapted to us, and us to them, and
we use them to stimulate our immune system," said Dennis Kasper, a
professor of medicine, microbiology and immunobiology at Harvard Medical
SOURCE: Chicago Tribune