Detecting amyloid positivity in early Alzheimer's disease using combinations of plasma Aβ42/Aβ40 and p-tau

Alzheimers Dement. 2022 Feb;18(2):283-293. doi: 10.1002/alz.12395. Epub 2021 Jun 20.

Abstract

Introduction: We studied usefulness of combining blood amyloid beta (Aβ)42/Aβ40, phosphorylated tau (p-tau)217, and neurofilament light (NfL) to detect abnormal brain Aβ deposition in different stages of early Alzheimer's disease (AD).

Methods: Plasma biomarkers were measured using mass spectrometry (Aβ42/Aβ40) and immunoassays (p-tau217 and NfL) in cognitively unimpaired individuals (CU, N = 591) and patients with mild cognitive impairment (MCI, N = 304) from two independent cohorts (BioFINDER-1, BioFINDER-2).

Results: In CU, a combination of plasma Aβ42/Aβ40 and p-tau217 detected abnormal brain Aβ status with area under the curve (AUC) of 0.83 to 0.86. In MCI, the models including p-tau217 alone or Aβ42/Aβ40 and p-tau217 had similar AUCs (0.86-0.88); however, the latter showed improved model fit. The models were implemented in an online application providing individualized risk assessments (https://brainapps.shinyapps.io/PredictABplasma/).

Discussion: A combination of plasma Aβ42/Aβ40 and p-tau217 discriminated Aβ status with relatively high accuracy, whereas p-tau217 showed strongest associations with Aβ pathology in MCI but not in CU.

Keywords: Alzheimer's disease; Aβ42/Aβ40; amyloid; blood biomarkers; neurofilament light; p-tau217.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease*
  • Amyloid
  • Amyloid beta-Peptides
  • Amyloidosis*
  • Biomarkers
  • Cognitive Dysfunction*
  • Humans
  • Peptide Fragments
  • Positron-Emission Tomography / methods
  • tau Proteins

Substances

  • Amyloid
  • Amyloid beta-Peptides
  • Biomarkers
  • Peptide Fragments
  • amyloid beta-protein (1-42)
  • tau Proteins