STANFORD, Calif. Ten years ago, Stanford University School of Medicine scientist Emmanuel Mignot, MD, PhD, and his colleagues made headlines when they identified the culprit behind the sleep disorder narcolepsy. Now Mignot and his collaborators have shown for the first time that a specific immune cell is involved in the disorder confirming experts' long-held suspicion that narcolepsy is an autoimmune disease.
The work, which will be published online May 3 in Nature Genetics, could lead to better treatments for the sleep disorder and help immunologists understand other, more common autoimmune diseases, such as multiple sclerosis and juvenile diabetes.
"We're now getting the main pieces of what's happening in narcolepsy," said Mignot, a Howard Hughes Medical Institute investigator who has been studying the disease for more than two decades. "What's most satisfying to me is that we're bringing this story to a close and that we can use narcolepsy as a model for other diseases."
Narcolepsy affects about one in 2,000 people and is characterized by daytime drowsiness, irregular sleep at night and cataplexy a sudden loss of muscle tone and strength. Mignot and others showed in the late 1990s that the disease stems from a lack of hypocretin, a hormone that promotes wakefulness; they later showed that narcoleptics are missing brain cells that produce this hormone.
Mignot and others believe that the body's immune system plays a role in killing hypocretin-making cells, primarily because of scientific literature showing a link between narcolepsy and a variant for the human leukocyte antigen, or HLA, gene. The immune system uses HLAs to differentiate between "self" cells and foreign cells (and attacks those presented as foreign), and most autoimmune diseases are associated with variants of HLA. In recent studies, more than 90 percent of narcolepsy patients were shown to carry one such variant.
"For a long time, peopl
|Contact: Michelle Brandt|
Stanford University Medical Center