IL6 and Alzheimer disease: Additionally, high levels of TNF-α, IL-1β, IL-6, IL-12, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in plasma increased gut permeability in aging macaques, which was associated with leaky gut, inflammatory phenotype, and dysbiosis of gut microbiota, leading to AD and neurological disorders through a gut-brain axis pathway (Schneider et al., 2019; Sochocka et al., 2019).