Immune response may cause harm in brain injuries, disorders

Could the body's own immune system play a role in memory impairment and cognitive dysfunction associated with conditions like chronic epilepsy, Alzheimer's dementia and concussions? Cleveland Clinic researchers believe so, based on a study published online by PLOS ONE.

The study focuses on the role of a protein known as S100B, which serves as a biomarker for . Normally, S100B is found only in the brain and spinal column. However, following a brain injury, it can leak through the into the blood.

Once S100B enters the bloodstream, it is identified as an intruder by the immune system, which releases antibodies to attack the protein.

"Our results show an unexpected role for S100B in the regulation of a neuro-, connecting the function of the brain to the ," said Damir Janigro, Ph.D., senior author and molecular medicine researcher at Cleveland Clinic's Lerner Research Institute. "Uptake of S100B was prominent in cells that are known to be involved in regulating immune responses. Repeated increases of S100B – whether due to , Alzheimer's disease, or repeated hits to the head in sporting events – may thus become boosters of an against the brain, which may slowly but inexorably result in chronic neurological disease."

These findings are the first to report a connection between a brain-derived protein and an immune response in the context of normal immunological function.

"Prior to this research, S100B autoantibodies have been described in a variety of diseases, primarily in Alzheimer's dementia and chronic epilepsy. More recently, repeated subconcussive episodes in football players included a post-game increase of S100B, followed by an autoimmune response against the protein," Janigro said. "Therefore, it appears that autoimmunity against brain proteins may be one of the initial steps in the progression towards posttraumatic cognitive decline."

The study tested the hypothesis that the presence of S100B in extracranial tissue is due to the production of antigen-presenting cells in the blood, which may induce the production of auto-antibodies against S100B. To test this hypothesis, researchers used animal models of seizures, enrolled patients undergoing repeated disruption of the blood-brain barrier, and collected blood samples from epileptic patients.

If further research confirms the study's findings, treatments for may include anti-inflammatory therapy or immunomodulators to decrease the autoimmune response, as has been done in the treatment of multiple sclerosis and myasthenia gravis.

add to favorites email to friend print save as pdf

Related Stories

On-field blood test can diagnose sports concussions

Jan 08, 2014

A brain protein, S100B, which may soon be detected by a simple finger-stick blood test, accurately distinguishes a sports-related concussion from sports exertion, according to a study of college athletes in Rochester, N.Y., ...

Researchers discover neuroprotective role of immune cell

Jul 22, 2014

A type of immune cell widely believed to exacerbate chronic adult brain diseases, such as Alzheimer's disease and multiple sclerosis (MS), can actually protect the brain from traumatic brain injury (TBI) and may slow the ...

New knowledge about the brain's effective bouncer

Jul 16, 2014

Research from the University of Copenhagen is shedding new light on the brain's complicated barrier tissue. The blood-brain barrier is an effective barrier which protects the brain, but which at the same ...

Recommended for you

Owls and lizards lend their ears for human hearing research

5 minutes ago

Lizards and owls are some of the animal species that can help us to better understand hearing loss in humans, according to new research out of York University's Department of Physics & Astronomy in the Faculty of Science.

Team finds key to tuberculosis resistance

4 hours ago

The cascade of events leading to bacterial infection and the immune response is mostly understood. However, the molecular mechanisms underlying the immune response to the bacteria that causes tuberculosis ...

Mutation may cause early loss of sperm supply

5 hours ago

Brown University biologists have determined how the loss of a gene in male mice results in the premature exhaustion of their fertility. Their fundamental new insights into the complex process of sperm generation ...

No more bleeding for 'iron overload' patients?

7 hours ago

Hemochromatosis (HH) is the most common genetic disorder in the western world, and yet is barely known. Only in the US 1 in 9 people carry the mutation (although not necessarily the disease).

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.