Pedrini et al. (2017) found proteins eotaxin-3, leptin, and PYY to be altered in individuals with AD in correspondence with their APOE ε4 status. More recently, Boccardi et al. (2019) observed that a joint expression of three proteins (IFN-α2, IL-1α, and TNFα) could discriminate HC from AD with an accuracy of 65.24%. Here, PYY is linked to Alzheimer disease.