Depleting myeloid-biased haematopoietic stem cells rejuvenates aged immunity. (https://pubmed.ncbi.nlm.nih.gov/38538791/)

These scientists wanted to understand how our immune system changes as we get older. They found that as we age, our immune system becomes less effective at fighting off infections and more prone to inflammation. They discovered that a certain type of cells in our blood, called haematopoietic stem cells (HSCs), play a big role in these changes.

In young people, there are two types of HSCs - one that produces both immune cells and inflammatory cells in a balanced way, and another type that mainly produces inflammatory cells. As we age, the balance shifts towards more of the inflammatory cell-producing HSCs, leading to a weaker immune system.

The scientists wanted to see if they could reverse this aging effect by getting rid of the inflammatory cell-producing HSCs in older mice. They used special antibodies to target and remove these cells. They found that when they removed these cells, the immune system of the older mice started to look more like that of younger mice. The older mice had more immune cells that fight off infections and less signs of immune decline.

This study suggests that by targeting these specific cells, we might be able to help older individuals have a stronger immune system and better protection against infections.

Ross JB., Myers LM., Noh JJ., Collins MM., Carmody AB., Messer RJ., Dhuey E., Hasenkrug KJ., Weissman IL. Depleting myeloid-biased haematopoietic stem cells rejuvenates aged immunity. Nature. 2024 Apr;628(8006):162-170. doi: 10.1038/s41586-024-07238-x. Epub 2024 Mar 27.