Tuesday, May 5, 2009

Tuesday Narcolepsy Geek-Out

There is new scientific evidence that narcolepsy is an autoimmune disorder:

The researchers analyzed DNA from nearly 4000 participants, all of whom shared the same narcolepsy-linked HLA but only about half of whom had narcolepsy. They found that the narcoleptics in the study shared a version of another gene that tells T cells--the immune cells that destroy intruders--how to react to the pathogens that HLA molecules bring them. The result indicates that T cells and HLA, which together regulate much of the body's immune response, gang up in a unique way to destroy narcoleptics' hypocretin cells, the team reports online this week in Nature Genetics.

The study doesn't explain why T cells target the hypocretin cells specifically, says Mignot. It also sheds no light on what triggers the attack in the first place, a mystery for most autoimmune diseases.
If I read this correctly, it suggests that the key mechanism lies in this "version of another gene that tells T-cells ... how to react to ... pathogens": this gene is instructing T-cells to attack "hypocretin cells," which they do with ruthless efficiency, depriving the body of its normal means of sleep regulation. Consequently, I'd rather be napping.

I put "hypocretin cells" in scare-quotes because hypocretin is a chemical, not a cell; by "hypocretin cells," I take it the reference is to the cellular systems that generate or receive (or both) hypocretin.

I'm not sure what possibilities this study opens for effective treatments (as opposed to prevention) -- I've been given to understand that once the "hypocretin cells" are destroyed, they're gone for good. Maybe that was my neurologist's oversimplification in light of my near-perfect ignorance of brain physiology and chemistry.

On such things as narcolepsy's causes, knowledge is necessary even if not sufficient. Surely this will open new lines of research that will in turn create new and better answers. Yay science!

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