AD-related gene networks were consistently upregulated, including an early and strong activation of cytokine pathway (e.g., Ccl3, Ccl4, Csf3r, Osmr) and complement pathways (e.g., C1qc, C1qa, C1qb, C3, C3ar1); similarly, the Fc pathway was also heavily activated (e.g., Fcgr1, Fcgr2b, Dock), although at subsequent stages. The gene discussed is C3; the disease is Alzheimer disease.