Autoimmune Diseases: It's Not Just the Genes
The results could also explain how men and women without children get scleroderma, she says. Babies in the womb pick up some of their mother's cells, so foreign "maternal cells could also engraft and persist in a child," she says.
Scleroderma occurs in 14 of every million people, and is much more common in women than in men.
Other findings in mice show that it takes more than the wrong gene to cause autoimmune disease.
A team led by Denise Faustman, MD, PhD, studied a genetically identical line of mice that usually develop type 1 diabetes. But rather than develop diabetes, some of the mice developed rheumatoid arthritis instead. Just as in humans, the arthritis occurred about 75% of the time in females, and it occurred in middle age. Faustman is director of the Immunobiology Labs at Massachusetts General Hospital and an associate professor of medicine at Harvard Medical School in Boston.
"It demonstrates the same gene can cause two different phenomena," she says. What's more, the mice also come down with the same symptoms of rheumatoid arthritis as humans, and middle-aged females tend to get it more than anybody else. That makes this mouse line a great model for researchers to study the causes and possible treatments of rheumatoid arthritis, Faustman says.
The results of both studies could help researchers find "novel ways of approaching treatment and even possible prevention of autoimmune disease," Rose says. Today, the best physicians can do is to treat patients with drug that dampens the immune response, but in the future drugs that target foreign cells could help.
What's more, the fact that both men and women have cells from our mothers, and women also have cells from their children, could even alter our traditional notion of who we are, Nelson says.
"Our concept of self will have to be conditional," she says -- it seems we're not necessarily the people we thought we were.