PPIB and Alzheimer disease: Although the two most well-established diagnostic criteria for AD both acknowledge the importance of Αβ and tau pathology in AD pathogenesis1, an important distinction is that the National Institute on Aging and Alzheimer’s Association (NIA-AA) criteria2 define AD by its biological features (that is, the presence of Αβ and tau pathology) irrespective of the clinical syndrome, whereas the International Working Group (IWG) criteria3 require the presence of objective cognitive impairment (mild cognitive impairment (MCI) or dementia) in conjunction with positive AD biomarkers.