A group of researchers has finally found evidence to confirm what many have long suspected: Narcolepsy is an autoimmune disease. The hypothesis has been swirling since 2009, when at least 900 children developed the chronic drowsiness disorder after being given a swine flu vaccine from GlaxoSmithKline, Scientific American and Reuters explain. That suggested that the narcolepsy was caused by the body's immune response to the H1N1 protein in the vaccine.
Now, a team of Stanford researchers thinks it knows what happened. Narcolepsy is largely caused by the loss of the neurons that produce the wakefulness hormone hypocretin. What the researchers found was a type of T-cell (the cells produced by immune responses) that specifically targeted hypocretin—and only existed in narcoleptics. "I think these cells are a smoking gun," one of the lead researchers says. An unaffiliated neurologist agrees. "It's one of the biggest things to happen in the field of narcolepsy for some time." (Read more narcolepsy stories.)