TNF and Alzheimer disease: AD mice display significant reductions in the abundance of members of the phyla Firmicutes, Verrucomicrobia, Proteobacteria, and Actinobacteria, and increases in that of members of Bacteroidetes and Tenericutes (Harach et al., 2017); these changes may cause TNF-mediated inflammation of the gastrointestinal tract, thereby increasing the risk of AD (Schaubeck et al., 2016).