More MS news articles for June 2001

Autoimmune Response Protects Against Neurodegeneration

http://www.medscape.com/reuters/prof/2001/06/06.26/20010625scie002.html

WESTPORT, CT (Reuters Health) Jun 25 - The natural autoimmune response to central nervous system (CNS) injury protects against delayed neurodegeneration, according to a report in the June 1st issue of the Journal of Neuroscience.

Delayed neurodegeneration often follows primary axonal injury in the CNS, the authors explain, but the role of the immune system in causing or mitigating that damage has been controversial.

In a series of experiments in rats and mice, Dr. Michal Schwartz from The Weizmann Institute of Science, Rehovot, Israel, and colleagues examined whether injury could trigger a beneficial autoimmune response.

Rats subjected to spinal cord contusion 7 to 17 days before optic nerve crush injury had significantly greater numbers of surviving optic neurons than did rats without prior contusion, the authors report, suggesting that CNS injury evoked a systemic neuroprotective response.

Moreover, this beneficial effect could be transferred by injection of T lymphocytes from spinally injured rats exposed to myelin basic protein, the report indicates. Adult rats subjected to thymectomy at birth were unable to mount the protective autoimmune response to CNS injury.

In further support of the autoimmune-mediated protective effect, transgenic mice overexpressing a T-cell receptor for myelin basic protein showed significantly more surviving retinal ganglion cells after axonal injury than did wild-type mice.

"This is the first demonstration, confirmed by four independent experimental approaches, that a T-cell-dependent autoimmunity is evoked for the benefit of the individual," the authors conclude. "These results support our contention that autoimmune protection, being the body's own physiological (although inadequate) response to injury, is worth boosting for therapeutic purposes."

"Autoimmunity and autoimmune disease are separate entities," Dr. Schwartz noted in comments to Reuters Health. "Autoimmunity is a purposeful physiological response. If it is defective it may become destructive, leading to autoimmune disease development."

"The subjects of autoimmunity and autoimmune disease should be revisited," Dr. Schwartz said. "When treating an autoimmune disease, physicians should take care to avoid immune suppression, and aim [instead] for immune modulation."

J Neuroscience 2001;21:3740-3748.
 

Copyright © 2001 Reuters Ltd.