Study Explains How Immune System Weakens

A U.S. study shows less effective immune system cells tend to overpopulate as people get older, which may explain why the immune system worsens with age.

The finding might prove useful in developing ways to slow the deterioration of the immune system, which could help protect elderly from infectious diseases, such as the flu, scientists at Oregon Health and Science University write in the Journal of Experimental Medicine.

In the study, the researchers used a strain of mice that have immune systems very similar to humans. The scientists found older mice had greater levels of a specific type of immune system cell called T cell clonal expansions or TCE, which are known to be less effective at fighting disease than other immune system cells.

The researchers also found increasing TCE cells in normal, healthy mice inhibited their ability to fight off disease.

If we can find ways to limit the production of TCE in the aging, we might be able to keep their immune systems strong and better able to fight disease, said Dr. Janko Nikolich-Zugich, a senior scientist and principal author.