Immune System May Attack Brain in Parkinson's Disease

The results from a new study published by Nature suggest that T cells may have an important and previously unknown role in Parkinson’s disease (PD).

PD is a neurodegenerative condition characterized by the death of dopamine-producing brain cells, which results in tremors, muscle stiffness, loss of balance, and slowed movement. There is currently no cure for PD and the underlying causes of the condition are not well-understood.

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

In the study, the authors collected blood samples from 67 patients with PD and 36 healthy patients. The authors extracted immune cells from the samples and mixed it with alpha-synuclein protein, which accumulates in the brain of patients with the disease.

The authors discovered that T cells from patients with PD had a higher response to alpha-synuclein compared with the cells from control patients, according to the study.

There were 2 regions of the protein that caused reactions from T cells: a section that is frequently mutated in PD and a portion that can undergo a chemical change that leads to the aggregation of the protein.

The authors also identified 4 gene variants that were linked to T cell reactivity to the protein, according to the study. Approximately 50% of patients with PD had the variants, while only 20% of controls were observed to have the variants.

“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 lead researcher Alessandro Sette, Dr.Biol.Sci.

The authors suggest that PD may have the characteristics of an autoimmune condition based on their findings.

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

Additional research is needed to explore the interactions between immune cells and alpha-synuclein. Achieving a better understanding of the interactions could lead to information regarding disease progression and potential links to other neurodegenerative diseases, according to the study.