Stanford Study Finds Bone Marrow Cells in Brain Influence Alzheimer

Researchers at Stanford University examined brain tissue from 20 older adults and identified immune cells that originated in the bone marrow. Single‑cell analyses showed these cells closely resemble microglia and can make up a substantial proportion of the brain's microglial population.

Analysis of larger human cohorts indicated that forms of clonal hematopoiesis—where blood cells derive from a single stem cell—are associated with a lower risk of Alzheimer disease. While the findings suggest a possible protective link, they do not prove causation. The results challenge the prevailing mouse‑based view that microglia are solely embryonic and persist unchanged throughout life. The study was posted as a pre‑print on Nature and is pending peer‑review.