Based on these studies, the results show significant predictability in the progression of AD and some systemic inflammatory markers such as high serum complement components (C3, C4, C5), complement regulator proteins (FH, FI), a soluble form of a complement receptor (sCR1), a classical marker of inflammation (CRP), and chemokines (eotaxin-1, MCP-1, and MIP-1b) [11]. This evidence concerns the gene C3 and Alzheimer disease.