A research team has developed a blood test that leverages the body’s immune response system to detect an early stage of Alzheimer’s disease – referred to as the mild cognitive impairment (MCI) stage – with high accuracy. In a proof-of-concept study involving 236 subjects, the test demonstrated an overall accuracy, sensitivity and specificity rate of 100 percent in identifying subjects whose MCI was actually caused by an early stage of Alzheimer’s disease.
The team was led by Dr. Robert Nagele from the Rowan University School of Osteopathic Medicine along with Durin Technologies, Inc.
“About 60 percent of all MCI patients have MCI caused by an early stage of Alzheimer’s disease,” Cassandra DeMarshall, the study’s lead author, and a PhD candidate at the Rowan Graduate School of Biomedical Sciences, commented. “The remaining 40 percent 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 aded that the findings could eventually lead to the development of a simple, inexpensive and relatively noninvasive way to diagnose thedisease in its earliest stages.
The researchers presented their results in an article published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring that also reported the test’s ability to accurately “stage the disease,” meaning it can distinguish early-stage Alzheimer’s at MCI from later, more advanced stages. The test was also disease-specific. It readily distinguished early Alzheimer’s at the MCI stage from other diseases including Parkinson’s disease, multiple sclerosis, and early stage breast cancer.
For the study, the Rowan University researchers analyzed blood samples from 236 subjects, including 50 MCI subjects with low levels of amyloid-beta 42 peptide in their cerebrospinal fluid. The latter is a reliable indicator of ongoing Alzheimer’s pathology in the brain and predicts a likely rapid progression to Alzheimer’s.
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 percent 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 percent), early-stage Parkinson’s disease (98.0 percent), multiple sclerosis (100 percent) and breast cancer (100 percent), the research team reported.
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 point 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, the approach could open the door to even earlier pre-symptomatic detection of Alzheimer’s disease.