Novel Blood Test Detects Early Alzheimer’s Disease

STRATFORD, NJ -- June 8, 2016 -- Researchers have developed a blood test that leverages the body’s immune response system to detect mild cognitive impairment (MCI).

In a proof of concept study involving 236 individuals, the test demonstrated an overall accuracy, sensitivity, and specificity rate of 100 percent in identifying those whose MCI was actually caused by an early stage of Alzheimer’s disease.

“About 60% of all patients with MCI have MCI caused by an early stage of Alzheimer’s disease,” said lead author Cassandra DeMarshall, Rowan University Graduate School of Biomedical Sciences, Stratford, New Jersey. “The remaining 40% of cases are caused by other factors, including vascular issues, drug side-effects and depression.”

“To provide proper care, physicians need to know which cases of MCI are due to early Alzheimer’s and which are not,” she said. “Our results show that it is possible to use a small number of blood-borne autoantibodies to accurately diagnose early-stage Alzheimer’s. These findings could eventually lead to the development of a simple, inexpensive and relatively noninvasive way to diagnose this devastating disease in its earliest stages.”

“It is now generally believed that Alzheimer’s-related changes begin in the brain at least a decade before the emergence of tell-tale symptoms,” said Robert Nagele, Rowan University School of Osteopathic Medicine. “To the best of our knowledge, this is the first blood test using autoantibody biomarkers that can accurately detect Alzheimer’s at an early point in the course of the disease when treatments are more likely to be beneficial -- that is, before too much brain devastation has occurred.”

For the study, published in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, the researchers analysed blood samples from 236 subjects, including 50 patients with MCI with low levels of amyloid-beta 42 peptide in their cerebrospinal fluid.

Employing human protein microarrays, each containing 9,486 unique human proteins that are used as bait to attract blood-borne autoantibodies, the researchers identified the top 50 autoantibody biomarkers capable of detecting ongoing early-stage Alzheimer’s pathology in patients with MCI.

In multiple tests, the 50 biomarkers were 100% accurate in distinguishing patients with MCI due to Alzheimer’s from healthy age- and gender-matched controls.

Further testing of the selected MCI biomarker panel demonstrated similar high overall accuracy rates in differentiating patients with early Alzheimer’s at the MCI stage from those with more advance, mild-moderate Alzheimer’s (98.7%), early-stage Parkinson’s disease (98.0%), multiple sclerosis (100%), and breast cancer (100%).

In their report, the researchers acknowledge that the utility of their MCI biomarker panel as a blood test for early detection of Alzheimer’s disease will hinge on a successful larger replication study using an independent patient cohort. However, they also pointed out that, because this blood-based diagnostic strategy is dependent on the presence of Alzheimer’s pathology which can be underway many years before symptoms emerge, this approach could open the door to even earlier pre-symptomatic detection of Alzheimer’s disease.

SOURCE: Rowan University
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