IL6 and Alzheimer disease: Several possible biomarkers for AD onset and progression have been suggested in this context, most related to the immune system, inflammation, and oxidative stress, such as phagocytic capacity against Aβ [49], proliferative response, chemotaxis, cytokines (IL-1β, IL-2, IL-6, TNFα...), glutathione or glutathione regulatory enzymes, thiobarbituric acid reactive substances (TBARS), and malondialdehyde (MDA) [21,23,42,46,49,50,51,52,53,54,55].