Washington University study links lymph node signals to Alzheimer's neurodegeneration

September 27, 2026 at 05:00 AM2 min

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Scientists at Washington University School of Medicine in St. Louis identified a lymph node signaling pathway that prepares T cells to enter the brain and drive neurodegeneration in mice. Disrupting these signals dramatically reduced tau-related brain damage, according to a study published Sept. 3 in Nature Neuroscience. The findings point to a previously unrecognized immune mechanism outside the brain that could be targeted to slow or halt Alzheimer's disease and primary tauopathies.

Key Facts

The study was published Sept. 3 in Nature Neuroscience.
Disrupting lymph node signals that prepare T cells to enter the brain dramatically reduced neurodegeneration in mice.
The findings may offer a way to slow or halt damage associated with Alzheimer's disease and primary tauopathies, which are marked by twisted accumulations of tau protein.
Senior author David M. Holtzman, MD, said the discovery identifies a disease-related process that begins outside the brain, potentially allowing treatments that do not need to cross the blood-brain barrier.

Immune Pathway Discovery

The study from Washington University School of Medicine in St. Louis found that T cells receive signals from lymph nodes that appear to prepare them to enter the brain and contribute to damage. When the scientists disrupted those signals, neurodegeneration was dramatically reduced in mice modeling tau-related damage. The findings reveal a previously unrecognized immune pathway that may offer a way to slow or potentially halt damage associated with Alzheimer's disease and primary tauopathies. These disorders are marked by twisted accumulations of tau protein in the brain.

T Cell Origins

Holtzman's laboratory previously showed that removing T cells from the brain prevented much of the neurodegeneration that normally develops in mice modeling tau-related damage. The new study traced those immune cells back to lymph nodes, where they receive signals from dendritic cells. Certain T cells rely on other immune cells, known as dendritic cells, to identify the molecular targets they should attack. Very few of the relevant dendritic cells, known as classical dendritic cells type 1 (cDC1), are found in the brain.

Therapeutic Implications

Senior author David M. Holtzman, MD, said the discovery is especially intriguing because it identifies a disease-related process that begins outside the brain. That could make it possible to target mechanisms that are easier to reach and better understood. Holtzman noted that treatments for neurological diseases typically need to cross the blood-brain barrier, but this pathway might not require that. He added that many ways to manipulate T cells have been studied extensively and are approved treatments for other diseases, but have not yet been explored for neurodegenerative diseases.