New blood test shows great promise in the diagnosis of Alzheimer's
disease

Date:
July 29, 2020
Source:
Lund University
Summary:
A new blood test demonstrated remarkable promise in discriminating
between persons with and without Alzheimer's disease and in persons
at known genetic risk may be able to detect the disease as early
as 20 years before the onset of cognitive impairment, according
to a large international study.



FULL STORY ========================================================================== [Alzheimer's blood test, | Credit: (c) felipecaparros / stock.adobe.com] Alzheimer's blood test, photo concept (stock image).

Credit: (c) felipecaparros / stock.adobe.com [Alzheimer's blood test,
| Credit: (c) felipecaparros / stock.adobe.com] Alzheimer's blood test,
photo concept (stock image).

Credit: (c) felipecaparros / stock.adobe.com Close A new blood test demonstrated remarkable promise in discriminating between persons with
and without Alzheimer's disease and in persons at known genetic risk may
be able to detect the disease as early as 20 years before the onset of cognitive impairment, according to a large international study published
today in the Journal of the American Medical Association (JAMA) and simultaneously presented at the Alzheimer's Association International Conference.


==========================================================================
For many years, the diagnosis of Alzheimer's has been based on the characterization of amyloid plaques and tau tangles in the brain,
typically after a person dies. An inexpensive and widely available blood
test for the presence of plaques and tangles would have a profound impact
on Alzheimer's research and care. According to the new study, measurements
of phospho-tau217 (p-tau217), one of the tau proteins found in tangles,
could provide a relatively sensitive and accurate indicator of both
plaques and tangles - - corresponding to the diagnosis of Alzheimer's --
in living people.

"The p-tau217 blood test has great promise in the diagnosis, early
detection, and study of Alzheimer's," said Oskar Hansson, MD, PhD,
Professor of Clinical Memory Research at Lund University, Sweden, who
leads the Swedish BioFINDER Study and senior author on the study who spearheaded the international collaborative effort. "While more work
is needed to optimize the assay and test it in other people before it
becomes available in the clinic, the blood test might become especially
useful to improve the recognition, diagnosis, and care of people in the
primary care setting." Researchers evaluated a new p-tau217 blood test
in 1,402 cognitively impaired and unimpaired research participants from well-known studies in Arizona, Sweden, and Colombia. The study, which
was coordinated from Lund University in Sweden, included 81 Arizona participants in Banner Sun Health Research Institute's Brain Donation
program who had clinical assessments and provided blood samples in their
last years of life and then had neuropathological assessments after they
died; 699 participants in the Swedish BioFINDER Study who had clinical,
brain imaging, cerebrospinal fluid (CSF), and blood-based biomarker assessments; and 522 Colombian autosomal dominant Alzheimer's disease (ADAD)-causing mutation carriers and non-carriers from the world's
largest ADAD cohort.

* In the Arizona (Banner Sun Health Research Institute) Brain Donation
Cohort, the plasma p-tau217 assay discriminated between Arizona
Brain donors with and without the subsequent neuropathological
diagnosis of "intermediate or high likelihood Alzheimer's" (i.e.,
characterized by plaques, as well as tangles that have at least
spread to temporal lobe memory areas or beyond) with 89% accuracy;
it distinguished between those with and without a diagnosis of
"high likelihood Alzheimer's" with 98% accuracy; and higher ptau217
measurements were correlated with higher brain tangle counts only
in those persons who also had amyloid plaques.

* In the Swedish BioFINDER Study, the assay discriminated between
persons
with the clinical diagnoses of Alzheimer's and other
neurodegenerative diseases with 96% accuracy, similar to tau PET
scans and CSF biomarkers and better than several other blood tests
and MRI measurements; and it distinguished between those with and
without an abnormal tau PET scan with 93% accuracy.

* In the Colombia Cohort, the assay began to distinguish between
mutation
carriers and non-carriers 20 years before their estimated age at
the onset of mild cognitive impairment.

In each of these analyses, p-tau217 (a major component of Alzheimer's
disease- related tau tangles) performed better than p-tau181 (another
component of tau tangles and a blood test recently found to have promise
in the diagnosis of Alzheimer's) and several other studied blood tests.

Other study leaders include Jeffrey Dage, PhD, from Eli Lilly and Company,
who developed the p-tau217 assay, co-first authors Sebastian Palmqvist,
MD, PhD, and Shorena Janelidz, PhD, from Lund University, and Eric Reiman,
MD, Banner Alzheimer's Institute, who organized the analysis of Arizona
and Colombian cohort data.

In the last two years, researchers have made great progress in the
development of amyloid blood tests, providing valuable information about
one of the two cardinal features of Alzheimer's. While more work is needed before the test is ready for use in the clinic, a p-tau217 blood test
has the potential to provide information about both plaques and tangles, corresponding to the diagnosis of Alzheimer's. It has the potential to
advance the disease's research and care in other important ways.

"Blood tests like p-tau217 have the potential to revolutionize Alzheimer's research, treatment and prevention trials, and clinical care," said
Eric Reiman, MD, Executive Director of Banner Alzheimer's Institute in
Phoenix and a senior author on the study.

"While there's more work to do, I anticipate that their impact in both
the research and clinical setting will become readily apparent within the
next two years." Alzheimer's is a debilitating and incurable disease that affects an estimated 5.8 million Americans age 65 and older. Without the discovery of successful prevention therapies, the number of U.S. cases
is projected to reach nearly 14 million by 2050.


========================================================================== Story Source: Materials provided by Lund_University. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. Sebastian Palmqvist, Shorena Janelidze, Yakeel T. Quiroz, Henrik
Zetterberg, Francisco Lopera, Erik Stomrud, Yi Su, Yinghua Chen,
Geidy E.

Serrano, Antoine Leuzy, Niklas Mattsson-Carlgren, Olof Strandberg,
Ruben Smith, Andres Villegas, Diego Sepulveda-Falla, Xiyun Chai,
Nicholas K.

Proctor, Thomas G. Beach, Kaj Blennow, Jeffrey L. Dage, Eric
M. Reiman, Oskar Hansson. Discriminative Accuracy of Plasma
Phospho-tau217 for Alzheimer Disease vs Other Neurodegenerative
Disorders. JAMA, 2020; DOI: 10.1001/jama.2020.12134 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200729114404.htm

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