Learnings about the complexity of extracellular tau aid development of a blood-based screen for Alzheimer's disease

Alzheimers Dement. 2019 Mar;15(3):487-496. doi: 10.1016/j.jalz.2018.09.010. Epub 2018 Nov 9.

Abstract

Introduction: The tau protein plays a central role in Alzheimer's disease (AD), and there is huge interest in measuring tau in blood and cerebrospinal fluid (CSF).

Methods: We developed a set of immunoassays to measure tau in specimens from humans diagnosed based on current best clinical and CSF biomarker criteria.

Results: In CSF, mid-region- and N-terminal-detected tau predominated and rose in disease. In plasma, an N-terminal assay (NT1) detected elevated levels of tau in AD and AD-mild cognitive impairment (MCI). Plasma NT1 measurements separated controls from AD-MCI (area under the curve [AUC] = 0.88) and AD (AUC = 0.96) in a discovery cohort and in a Validation Cohort (with AUCs = 0.79 and 0.75, respectively).

Discussion: The forms of tau in CSF and plasma are distinct, but in each specimen type, the levels of certain fragments are increased in AD. Measurement of plasma NT1 tau should be aggressively pursued as a potential blood-based screening test for AD/AD-MCI.

Keywords: Biomarker; Dementia; Enzyme-linked immunoassay; Mild cognitive impairment; Plasma; Single molecule array.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Validation Study

MeSH terms

  • Aged
  • Alzheimer Disease / blood*
  • Alzheimer Disease / cerebrospinal fluid
  • Biomarkers / blood
  • Biomarkers / cerebrospinal fluid
  • Cognitive Dysfunction / blood*
  • Cognitive Dysfunction / cerebrospinal fluid
  • Cohort Studies
  • Diagnosis, Differential
  • Extracellular Space
  • Female
  • Humans
  • Immunoassay* / methods
  • Male
  • Middle Aged
  • Sensitivity and Specificity
  • tau Proteins / blood*
  • tau Proteins / cerebrospinal fluid

Substances

  • Biomarkers
  • MAPT protein, human
  • tau Proteins