At Montpellier University Hospital, a simple blood test can detect Alzheimer’s disease

Patiently, Professor Sylvain Lehmann, head of the biochemistry and clinical proteomics laboratory at the Montpellier University Hospital (Hérault), peels off several adhesive Post-its one after the other and assembles them on his desk. Using red and blue pencils, the man who heads one of the laboratories of excellence in French research into neurodegenerative diseases carefully draws the mechanism used by one of the machines he has just purchased to detect antibodies in the blood produced by a protein characteristic of Alzheimer’s disease. To his amazed eyes, he looks like a child preparing to receive the most beautiful gift at Christmas.

Across the corridor, among the quietly humming machines, this device is particularly revolutionary: since the beginning of September, it has been establishing, following a simple blood test, the blood counts of patients admitted to the hospital to find out if they are suffering from the disease. A first in France. And yet, with its air of a large photocopier with a robotic rhythm, one would not say that it alone represents an upheaval in the early diagnosis of Alzheimer’s.

A quick analysis

While blood tests have recently appeared in the United States, Professor Lehmann’s team has considerably refined them, by identifying the biomarker p-tau217, which is very reliable because it can be detected in infinitesimal quantities. “Our blood tests make it possible to complete doctors’ diagnoses and will probably one day make it possible to do without the battery of tests they need today,” says Professor Lehmann with his good-natured and confident smile. This major advance was made possible thanks to close collaboration with the Centre mémoire de ressources et de recherches (CMRR) in Montpellier, one of 266 in France, housed in the buildings next to the CHU. “The blood test now offered to our patients makes it possible to know quickly and precisely whether or not they are suffering from the disease, or from another form of dementia,” explains Dr. Cédric Turpinat, a neurologist at the CMRR.

Above all, a blood sample is much less invasive than the tests prescribed until now. Since the advent of medical imaging, the disease has been detected using positron emission tomography, magnetic resonance imaging (MRI) and a lumbar puncture. But these tests remain cumbersome and expensive. “We cannot offer them to patients with suspected but relatively mild disorders,” emphasizes Dr. Turpinat.

It was in 2020 that Professor Lehmann and his team identified one of the characteristic biomarkers of Alzheimer’s disease. The latter is characterized by two types of damage: the accumulation of “plaques” called amyloid, formed by the protein of the same name, which disrupts the communication of neurons; and neurofibrillary degenerations resulting from another protein, called tau, which alters the functioning of these neurons.

Anticipate symptoms

Thanks to a machine that is unique in France – the mass spectrometer – the professor managed to identify a specific biomarker for Alzheimer’s: the famous p-tau217. The latter has even become the most sought-after biomarker in analyses, because it also makes it possible to predict the evolution of protein accumulation. And this is the second major advance: the blood test carried out in Montpellier is revolutionizing the medical pathway linked to the disease: “The blood test can highlight its presence ten to fifteen years before the onset of symptoms,” explains Professor Lehmann. However, “early management is crucial to very quickly initiate specialized therapies adapted to the stage of the disease,” adds Dr. Turpinat.

Especially since last year, the first drugs that slow the progression of the disease have appeared on the market. The earlier they are administered, the more effective they are. Although the European Medicines Agency refused to market lecanemab, an anti-amyloid antibody, on July 25, it is already used in the United States, Japan and the United Kingdom. “We are in full swing: we have at the same time a non-invasive means of early diagnosis and treatments that are coming,” enthuses Professor Lehmann, who predicts the arrival of other markers. “The most anticipated is the one that will allow us to know in what time frame the person will develop the disease,” he adds, his eyes full of hope.