How ageing harms the body's response to raging infection

"Genes that protect the body against infection during youth can do harm in old age, according to a study in mice. The results hint that ageing lowers immunity in unexpected ways, not just by weakening the immune response. The study's authors report that the presence of a specific gene in the heart helped mice to survive virulent infections - but only if the mice were young. For old mice, the gene increased the risk of death."

""In one case it's protective. In another case, it actually drives death," says Andrew Wang, an immunologist at Yale University in New Haven, Connecticut, who was not involved in the research. The study shows that "the mechanisms that are protective to organs really can differ dramatically". These findings about how age affects the body's ability to endure invasion from pathogens, published in Nature on 14 January, might be a step towards developing therapies for diseases distinguished by broad immune dysfunction that damages the body, researchers say."

"Surviving an infection requires the immune system to fight off harmful invaders. But it also requires the body to avoid damage from pathogens and overzealous immune cells. Young individuals often withstand both infection and the immune defences that are unleashed by their bodies to kill off infectious organisms. "But as you get older, your ability to do that reduces," says Manu Shankar-Hari, an immunologist at the University of Edinburgh, UK."

Certain genes that protect against infection during youth can become harmful with age, increasing death risk in older mice. A specific cardiac gene improved survival after virulent infections in young mice but raised mortality in aged mice. Age-associated changes reduce the body's ability to endure damage from pathogens and immune responses, not merely weakening immune reactions. Sepsis, marked by immune overreaction and organ damage, exemplifies this decline in endurance with age. Organ-specific protective mechanisms vary with age and imply potential therapeutic targets for diseases involving immune-driven tissue damage.

Read at Nature