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Positing Parkinson’s as an autoimmune disease

Parkinson’s disease, like Alzheimer’s disease, is one of the leading neurodegenerative issues being targeted by the biopharmaceutical and life sciences industries today. It is the result of the death of neurons responsible for producing dopamine, which the Parkinson’s Disease Foundation describes as “A chemical messenger that regulates movement by assisting in the effective communication (transmission) of electrochemical signals in the brain from one nerve cell (neuron) to another.” When the dopamine deficiency increases, it results in the loss of autonomous movement control Parkinson’s disease is known for.
Given the role dopamine plays in the disease, most work has focused on trying to increase dopamine production. But a new study has suggested that attention should be turned onto the immune system, as Parkinson’s disease might be an autoimmune condition.

In a standard immune system, the body’s white blood cells recognize antigens—which can take the form of bacteria, viruses or toxins—on infected cells and produces T cells to destroy them. In autoimmune diseases, such as type 1 diabetes, multiple sclerosis, rheumatoid arthritis and lupus, the immune system mistakes healthy cells for antigens, which results in damage to healthy tissue.

Parkinson’s disease has not previously been considered in the category of autoimmune diseases because it the prevailing belief is that since neurons do not display antigens on their cell surfaces, they are safe from immune system attacks.
Cells display antigens with proteins known as MHCs. A team led by Dr. David Sulzer, professor of neurobiology in the departments of psychiatry, neurology and pharmacology at Columbia University College of Physicians & Surgeons, worked with postmortem brain tissue donated by healthy donors to the Columbia Brain Bank and found MHC-1 proteins in two types of neurons. Both types of neurons degenerate in patients with Parkinson’s disease, and one type is dopamine neurons located in the substantia nigra region of the brain. Dopamine deficiency is credited as one of the leading issues of Parkinson’s disease.