Looks at evidence that peripheral blood immune cells migrate into the aging human brain and adopt microglial identities, challenging brain isolation assumptions.
Key Takeaways
- Researchers used shared somatic mutations to trace blood-derived immune cells into human brain tissue
- Blood-derived immune cells enter the brain by middle age and differentiate into microglia-like cells
- This peripheral-to-brain immune exchange was observed in humans but not in mice or nonhuman primates