Immune system may mount an attack in Parkinson’s disease

T cells may play an important role in Parkinson’s disease (PD), according to a new study.

Researchers have found that T cells from people with PD responded to the presence of alpha-synuclein to a much greater degree than those gathered from a control group.

Two regions of alpha-synuclein evoked reactions from T cells: a section that often contains mutations linked with Parkinson’s. The researchers identified four genetic variations that were associated with T cell reactivity to alpha-synuclein. More than half of people with Parkinson’s carried at least one of those variants, compared to 20 percent of controls.

“This collaboration between neuroscientists and immunologists provides important new evidence for ways in which the immune system can play a role in Parkinson’s, a link that can be used to further define this interaction,” said Dr Beth-Anne Sieber, a program director at National Institute of Neurological Disorders and Stroke (NINDS).

A research team led by Dr David Sulzer, professor of neurology at Columbia University in New York City and Dr Alessandro Sette, professor of infectious diseases at the La Jolla Institute for Allergy and Immunology in California, examined the role of T cells in PD. The team collected blood samples from 67 individuals with Parkinson’s disease and 36 healthy controls. Immune cells were extracted from the samples and mixed with portions of the alpha-synuclein protein, which accumulates in the brains of people with PD and can result in cell death.

“These findings expose a potential biomarker for PD that may someday help in diagnosing the disease or be used to evaluate how well treatments are working,” said Dr Sette.

According to the authors, the results suggest that PD may have characteristics of an autoimmune disease, in which the immune system incorrectly attacks the body’s own cells.

“As we age, proteins throughout the body undergo various molecular modifications. If they become unrecognisable, the immune system may start going after them, thinking they may be dangerous invaders,” said Dr Sulzer.

More research is needed to learn about the interactions between immune cells and alpha-synuclein. Improved understanding of those interactions may lead to information about disease progression as well as potential connections to other neurodegenerative disorders.