Adapting Immunotherapies to Perform Well in the Aged Immune System
Researchers manage to make an immunotherapy work well in aged immune systems - which is important, as most of the potential uses for immune therapies will target older people: "a new study [shows] that some types of immunotherapy previously thought to work only in younger patients can be used to help the elderly, with less toxic effects than many common therapies, if combined in ways that account for age-related changes in the immune system. ... We've shown that immunotherapy for cancer not only works in aged mice, but actually can work better in aged hosts than in young counterparts by capitalizing on the immune changes that happen with age ... As you age, most parts of your body begin to wear out. They keep doing what they're made to do [but] over time, they don't do it as well. The general perception is that the immune system also simply declines with age. ... That's really too simplistic. That's really not the full picture of what's happening. ... The body's immune system does weaken with age, but it also changes, and that changes the rules for fighting disease within the body. [The researchers] started by examining an immune therapy that they previously had shown to work in younger hosts, including cancer patients. It's designed to eliminate regulatory T cells (called Tregs), which are cells that turn off immune responses, allowing cancer to progress. Tregs increase in cancer. In young hosts, the drug turns off Treg activity, allowing the immune system to function better. In older hosts, even though the drug turns off the Tregs, it has no clinical benefit. ... In older mice, when the drug turned off the Tregs, the researchers found that another type of immune suppressor cell (a myeloid-derived suppressor cell or MDSC) exploded in number to take the Tregs' place, hampering clinical efficacy. That did not happen in young mice. The team added a second drug that targets the MDSC, and found that with those tools to help immunity, the older hosts can combat cancer just as well as the younger hosts."
Link: http://www.eurekalert.org/pub_releases/2012-04/uoth-ife041012.php