TNF-α, IL-1β, IL-6, and CRP levels between the severe AD group and the mild and moderate AD groups were statistically significant (all P < 0.05), while TNF-α, IL-1β, IL-6, and CRP levels between the mild AD group and the moderate AD group were not significantly different (P = 0.055, 0.067, 0.093, 0.088). This evidence concerns the gene CRP and Alzheimer disease.