That's interesting. It sort of goes along with Rich's theory about excitotoxicity due to a drop in glutathione in the astrocytes. That thing about cysteine in the CSF concerns me since one of the places Lyme borrelia like to hang out is in the spinal fluid and they consume cysteine. One thing I'm wondering is about amino acids from food. I seem to remember reading somewhere that people with CFS/ME have a harder time absorbing amino acids from food. If that is true (and hopefully someone following this thread can confirm that) then that would mean we're getting less cysteine and methionine from our food so less glutathione and methylation. Also, less lysine and methionine would mean less carnitine.