Alzheimer's May Originate in Neck Lymph Nodes, Study Finds

A Nature Neuroscience study proposes that Alzheimer's-related brain damage may be driven by an immune response that begins outside the brain: dendritic cells in deep cervical lymph nodes prime CD8+ T cells, which then enter the brain and promote neuroinflammation. In mouse models, silencing cDC1s or blocking cross-presentation reduced T-cell brain infiltration and neurodegeneration without changing brain tau levels, suggesting the immune process outside the brain could be a key driver and a new therapeutic target via the brain's lymphatic system rather than direct CNS drug delivery.