Study conducted on mice by Stanford Medicine and the US National Institutes of Health’s Rocky Mountain Laboratories and published in the journal Nature, provides evidence that it may one day be possible to revive the immune system of elderly people with a treatment that modulates the synthesis of a type of immune cell.

As our immune system faces more and more challenges from unknown bacteria and viruses, vaccination in the elderly is not as effective while in the younger and new pathogenic micro-organisms they can impose themselves frighteningly quickly.

The cells the researchers targeted are a subset of so-called hematopoietic stem cells, or HSCs, which give rise to all other types of blood and immune system cells, including B and T lymphocytes. As we age, HSCs begin to favor increased production of other immune cells (myeloid cells) over lymphocytes, and this shift hinders our ability to fully respond to new viral or bacterial threats and makes our vaccination response much less robust than of younger people.

Treatment with an antibody given in the research, which targeted senescent cells for destruction, significantly improved the ability of the immune systems of older animals to deal with a new virus, as well as respond to vaccination, allowing them to fight off a new threat months later. The treatment also reduced inflammation that occurs when an aging immune system fights a new pathogen.

“If we can revive the aging human immune system, as we did in mice, this could be a lifesaver when the next global pathogen emerges,” points out Irving Weisman, professor of Pathology and Evolutionary Biology at Stanford University and one of the study’s lead authors. Weissman was the first to isolate HSCs in mice and humans in the late 1980s.

Preclinical and clinical studies are needed to determine whether this approach may be feasible in humans. However, in an accompanying article published in Nature, Yasar Arfat Kasou and Robert Shiner of the University of California, San Diego, warn that increased lymphoid cell production in older adults could potentially increase the risk of developing tumors (such as leukemia). , which have been shown to be suppressed by reduced lymph production. “However, the burden of increased risk of lymphogenous leukemia could be offset by greater protection against infections and reduced risk of other cancers resulting from enhanced immune surveillance,” they add.