Narcolepsy may be an autoimmune disorder. That means that the immune system of the narcoleptic is not just attacking foreign invaders, it is attacking the body's own cells.
"Researchers at the University of Lausanne, Switzerland, have now identified auto-antibodies (immune molecules that target a natural protein in the body rather than a protein from an infectious agent) that target a natural protein called Trib2 in narcolepsy patients who experience paralysis linked to their emotions. This clearly suggests that narcolepsy could be an autoimmune disorder. Normally, the immune system can distinguish between 'self' and 'not self' and only attacks those tissues that it recognizes as foreign, or 'not self.' But when it comes to narcolepsy, it seems we could have a mutiny on our hands."
Some signs of narcolepsy are overwhelming sleepiness during the day and sudden weakness or paralysis triggered by intense feelings, as well as sleep paralysis.
There is as yet no cure for narcolepsy, though naps can sometimes be an effective substitute for stimulant medications.
http://www.theinsomniablog.com/the_insomnia_blog/2010/06/narcolepsy-an-autoimmune-disorder.html?utm_sourceg)