CXCL8 and Alzheimer disease: Findings regarding the associations between AD and inflammatory cytokines, including interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-18, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, interferon (IFN)-γ, and the C-reactive protein are controversial (Julian et al., 2015).