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]. The gene discussed is C5; the disease is Alzheimer disease.