http://www.heartfixer.com/AMRI-Nutrigenomics.htm has additional info about
methylation and the genetic variants some people can have that can affect the methylation cycle. Glutathione is NOT good for those of us who have the gene variant that increases sulfur and ammonia (like me). If you have no trouble tolerating sulfur foods (onions, garlic, asparagus, broccoli, cauliflower, cabbage, eggs, etc.) then you likely don't have a problem with this particular gene variant (the Cystathione Beta Synthase variant).
Edited to add: For the person who asked about CD8, CD8 is a type of lymphocyte (white blood cell) known as regulatory T-Cell. When CD8 is low, one can be more prone to developing autoimmune or allergic reactions to things because the regulatory T-Cells are insufficient in number to control lymphocyte response.