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.

Inclusion Criteria:

• Alzheimer's disease (AD)patients
• MMSE score: 16-25
• Written informed consent

Exclusion Criteria:

• AD patients with specific treatment for AD before inclusion MMSE score under 16 or over 25 at inclusion
• patients with anti-inflammatory drugs (non steroids or corticosteroids) or immunosuppressive agents
• Patients with acute disease (infectious disease, rheumatologic disease) or chronic disease (malignancy, infectious, rheumatologic disease) that could interact with plasma cytokines level
• Patients with a life threatening disease