Questions remain about how autoimmune disorder is triggered
The spark that ignites multiple sclerosis may come from within. A new study in mice points to normal intestinal bacteria as a trigger for the immune disorder.
In patients with multiple sclerosis, the body’s immune system attacks the brain, stripping away a protective sheath called myelin from nerve cells. This causes inflammation that leads to the disease. Although the exact causes of MS are not known, scientists generally agree that a genetic predisposition combines with one or more environmental triggers to set off the attack on the brain. The new study provides evidence that friendly bacteria may be one of those triggers.
Mice genetically engineered to develop multiple sclerosis–like symptoms don’t get the disease when raised without any bacteria in their guts, a research team from Germany reports online October 26 in Nature. But germ-free mice that were then colonized with intestinal bacteria quickly developed the disease, the team fo