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."