ALZHEIMER’S & DIMENTIA

Michelle M. Mielke, Clinton E. Hagen, Jing Xu, Xiyun Chai, Prashanthi Vemuri,
Val J. Lowe, David C. Airey, David S. Knopman, Rosebud O. Roberts, Mary M. Machulda,
Clifford R. Jack, Jr., Ronald C. Petersena, Jeffrey L. Dage

Alzheimer’s & Dimentia

DOI: 10.1016/j.jalz.2018.02.013

Abstract

Introduction: 

We examined and compared plasma phospho-tau181 (pTau181) and total tau: (1)
across the Alzheimer’s disease (AD) clinical spectrum; (2) in relation to brain amyloid b (Ab) posi-
tron emission tomography (PET), tau PET, and cortical thickness; and (3) as a screening tool for
elevated brain Ab.

Methods: 

Participants included 172 cognitively unimpaired, 57 mild cognitively impaired, and 40
AD dementia patients with concurrent Ab PET (Pittsburgh compound B), tau PET (AV1451),
magnetic resonance imaging, plasma total tau, and pTau181.

Results: 

Plasma total tau and pTau181 levels were higher in AD dementia patients than those in
cognitively unimpaired. Plasma pTau181 was more strongly associated with both Ab and tau PET.
Plasma pTau181 was a more sensitive and specific predictor of elevated brain Ab than total tau
and was as good as, or better than, the combination of age and apolipoprotein E (APOE).

Discussion: 

Plasma pTau181 may have utility as a biomarker of AD pathophysiology and as a noninvasive screener for elevated brain Ab.