Paolo Rossi Castelli 13 May 2020 8 min read

Could a blood test detect Parkinson’s in advance?

Parkinson’s disease has an autoimmune origin, at least in part, and the signs of the onset of this disease could be found well in advance by looking for autoimmunity “markers” in the blood. This is according to researchers from La Jolla Institute for Immunology (USA), who have published their results in the journal Nature Communications. “If you are able to diagnose the disease as early as possible, it could make a huge difference (in treating the disease – editor’s note)”, said Cecilia Lindestam Arlehamn, main author of the study.

We recall that Parkinson’s is a neurodegenerative disease that results in the damaging of several areas of the brain, causing mobility disorders, which may be very serious, as well as cognitive disorders. A key role in the disease is attributed to alpha-synuclein, a protein that, in an altered form, accumulates in several areas of the brain (for reasons still unknown), eventually destroying the neurons that produce dopamine, an essential neurotransmitter for muscle control.

Back in 2017 the researchers from La Jolla showed that alpha-synuclein can cause T lymphocytes (fundamental cells of the body’s defence system) to trigger auto-immune reactions. Basically, according to the researchers, when alpha-synuclein accumulates, it “attracts” T lymphocytes and makes them attack brain cells by mistake, thus contributing to the progression of Parkinson’s. However, it is not clear if these auto-immune reactions are an initial cause of the disease, or “only” worsen the degeneration of the neurons already compromised by the accumulation of alpha-synuclein.

In the study published in Nature Communications, the US researchers checked the “chronology” of the interaction between alpha-synuclein and T lymphocytes, and – by analysing the blood of a wide range of sufferers of the disease – demonstrated that there is a very specific temporal evolution in this delicate relationship. In particular, the researchers discovered that the T lymphocytes mistakenly “stimulated” by alpha-synuclein are found in abundant numbers many years before the appearance of the symptoms of the disease and that they are highly reactive. Then, with the passing of time, while the disease runs its course, these lymphocytes progressively decrease and finally disappear.

“The detection of T cell ‘responses’ could help in diagnosing people at risk or in the early stages of disease development, when many of the symptoms have not been detected yet”, explained Alessandro Sette, coordinator of the study. But this is not enough. If they were able to find the anti-alpha-synuclein T lymphocytes as soon as they formed, they could try to neutralize them before they increased the degeneration of nerve cells.

There already are therapies to treat the inflammation caused by auto-reactive T lymphocytes and the patients that use them, for other illnesses, have proven to be less prone to Parkinson’s disease. This also could be an indirect confirmation of the claims made by the researchers from California.


Paolo Rossi Castelli

Journalist since 1983, Paolo has been dealing with scientific divulgation for years, especially in the fields of medicine and biology. He is the creator of Sportello Cancro, the site created by on oncology in collaboration with the Umberto Veronesi Foundation. He collaborated with the pages of the Science of Corriere della Sera for several years. He is the founder and director of PRC-Comunicare la scienza.