Stem cells

Some stem cells are so efficient that just a few will do

Versatile stem cell completely replenishes the blood cells and immune system of macaques.

A potent type of stem cell can give rise to the entire immune system — and all blood cells.

Previous studies have suggested that several cell types, acting in waves, replenish blood and immune cells that are obliterated by chemotherapy or other causes. In a study in pig-tailed macaques (Macaca nemestrina), Hans-Peter Kiem at the Fred Hutchinson Cancer Research Center in Seattle, Washington, and his colleagues inserted genetic tags into thousands of types of stem cell and tracked them over time. The team found that low levels of a single type of stem cell were capable of generating all blood cells and the entire immune system, and maintaining them for up to 7.5 years. The scientists discovered that humans have a corresponding type of stem cell that expresses many of the same key genes.

The discovery could help to refine stem-cell therapies, potentially leading to treatment with fewer cells, fewer cell types and possibly fewer side effects, the researchers say.