Studies in laboratory mice and humans suggest that the immune system ages prematurely and malfunctions
Premature aging of the immune system appears to play a role in the development of amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, according to research scientists from the Maxine Dunitz Neurosurgical Institute at Cedars-Sinai Medical Center, the Weizmann Institute of Science in Israel, and Sheba Medical Center in Israel.
A study published in the Journal of Cellular and Molecular Medicine shows that CD4+ T cells, which grow and mature in the thymus before entering the bloodstream, are reduced in number in patients who have ALS as the thymus shrinks and malfunctions. Theoretically, devising therapies to support or replace these cells could be a strategy in treating the disease.
The research was led by Michal Schwartz, Ph.D., a visiting professor at the Center of Neuroimmunology and Neurogenesis in the Department of Neurosurgery at Cedars-Sinai and professor of neuroimmunology at the Weizmann Institute in Rehovot, Israel.
The findings are consistent with evidence collected over a decade by Schwartz's group suggesting that a well-functioning immune system plays a pivotal role in maintaining, protecting and repairing cells of the central nervous system. Studies conducted in animals have shown that boosting immune T-cell levels may reduce symptoms and slow progression of certain neurodegenerative diseases.
Results from the current study suggest that premature aging of the immune system and thus a decrease in protection from immune T cells could contribute to the aggressive and rapid progression of amyotrophic lateral sclerosis, which attacks motor neurons - nerve cells responsible for muscle strength and voluntary movements. The researchers found that thymic malfunction occurs simultaneously with motor neuron dysfunction, both in laboratory mice bred to mimic amyotrophic lateral sclerosis and in humans suffering from the disease.
Motor neurons extend from the brain to the spinal cord and from the spinal cord to the muscles of the body. Amyotrophic lateral sclerosis damages motor neurons in the spinal cord, leading to their death, the inability to control muscle action, and the wasting away of muscle tissue. About 5,600 people are diagnosed with amyotrophic lateral sclerosis each year. Up to 10 percent of cases are inherited because of certain gene mutations but the majority occur in the general population with no known cause.