Zeydan B, Lowe VJ, Reichard RR, et al. - Researchers investigated aging multiple sclerosis (MS) patients for β-amyloid and tau depositions using Pittsburgh compound B (PiB) PET and AV1451 tau PET imaging. They included 16 patients with MS and 80 controls in this study; the controls were matched for age, gender, and APOE ε4 status from the population-based Mayo Clinic Study of Aging who underwent PiB PET imaging. Patients with MS vs controls exhibited lower Alzheimer disease (AD)-signature PiB SUVr, total cortical PiB SUVr and the frequency of abnormal PiB SUVrs. While the groups showed no differences in AD-signature and total cortical AV1451 SUVrs, patients with MS vs controls exhibited higher frequency of abnormal AV1451 SUVrs. Steeper association of AD-signature PiB SUVr with age was evident in the controls vs patients with MS. Similarly, steeper association of total cortical PiB SUVr with age was evident in the controls vs patients with MS. The findings suggest the value of both β-amyloid and tau as biomarkers of cognitive aging and AD, however, MS vs age-matched controls indicated lower cortical β-amyloid deposition, hinting that some aspect of MS pathobiology hinders the accumulation of β-amyloid, but not the accumulation of tau.