Stanford study in Nature finds immune cells enter aging brain
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Stanford researchers report in Nature that immune cells from outside the body enter the human brain during aging. The finding challenges the view of the brain as a closed immune system.
Key Facts
- Earlier work showed people carrying certain clones of immune cells produced by mutated blood stem cells were much less likely to develop Alzheimer's.
- The mutations are associated with clonal hematopoiesis of indeterminate potential, a condition found in only a minority of people.
- Julia Belk, a postdoctoral scholar in pathology at Stanford Medicine, is the first author, and Siddhartha Jaiswal, an associate professor of pathology, is the senior author.
- The work was published in Nature and supported in part by the Knight Initiative for Brain Resilience at the Wu Tsai Neurosciences Institute.
Immune Cell Influx
Stanford researchers report in Nature that large numbers of immune cells from outside the body enter the human brain during aging. The finding challenges a decades-old view that the brain's immune system is largely separate from immune defenses elsewhere in the body. Julia Belk, a postdoctoral scholar in pathology at Stanford Medicine and first author, said scientists usually think of the brain as a closed system. Siddhartha Jaiswal, senior author and associate professor of pathology, said immune cells in the brain were presumed to renew themselves throughout the lifespan without contribution from outside the brain.
Earlier Genetic Work
The research grew from earlier work that examined genetic information from thousands of people, including some followed for decades. That work showed people carrying certain clones of immune cells produced by mutated blood stem cells were much less likely to develop Alzheimer's. The result led the researchers to ask whether immune cells from the blood routinely enter the brains of people as they grow older. The researchers later found evidence that some mutant cells can enter the brain itself. The mutations involve clonal hematopoiesis of indeterminate potential, a condition found in only a minority of people.
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Stanford study in Nature finds immune cells enter aging brain
