Cytokines and Cognitive Decline in Alzheimer's Disease

Amyloid plaques and neurofibrillary tangles are the 2 well-known etiopathological hallmarks of Alzheimer's disease (AD). Beside these 2 lesions, inflammation response is described in the brain of patients with AD. The main objective of our study is to analyse the correlation between the value of plasma cytokines (interleukin 1, 6, TNFα and chemochine Rantes) and the rapidity of the cognitive decline in AD over a 2-year follow-up. Secondary objectives include: * the predictive value of the cytokines on the cognitive decline after 6 months and one year of follow-up., of the patients include 150 patients with AD (MMSE: 16-25) * correlation between plasma cytokines levels and expression of the protein kinase PKR (involved in death cell) in blood mononuclear cells.