Skull bone marrow harbors immune hubs that respond to brain cancer in mice

September 16, 2026 at 05:00 AM2 min

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Researchers at Washington University School of Medicine in St. Louis identified lymph node-like immune structures in the skull bone marrow of mice. These structures respond rapidly to brain cancer, activating before distant lymph nodes receive signals. The team also found similar immune cells in human skull bone marrow, suggesting the defense system may not be limited to mice.

Key Facts

The study, published in Nature, is the first to identify immune hubs of this kind inside bone.
Senior author Jonathan Kipnis, PhD, is the Alan A. and Edith L. Wolff Distinguished Professor of Pathology & Immunology at WashU Medicine.
First author Jang Hyun Park, PhD, is a postdoctoral research fellow in the Kipnis lab and will start his own lab at the Korea Advanced Institute of Science and Technology this fall.
The researchers previously discovered lymphatic vessels in the dura mater and tiny physical channels bridging the skull, dura, and brain tissue.

Discovery of Skull Immune Hubs

Researchers at Washington University School of Medicine in St. Louis identified previously unknown lymph node-like immune structures in the skull bone marrow of mice. The findings suggest these nearby immune hubs can respond rapidly to brain cancer, becoming active before more distant lymph nodes even receive signals that something is wrong. The team also found evidence of similar immune cells in human skull bone marrow, suggesting that this local defense system may not be limited to mice. Published in Nature, the study is the first to identify immune hubs of this kind inside bone.

Mechanism and Significance

Earlier work from Kipnis' laboratory helped overturn the long-standing idea that the brain was separated from the immune system. The group discovered lymphatic vessels in the dura mater, the protective outer layer of tissue surrounding the brain just beneath the skull. More recently, the researchers found tiny physical channels bridging the skull, dura, and brain tissue, providing a direct route for immune cells and cellular waste to travel between the brain and nearby skull bone marrow. In the new mouse study, the scientists followed proteins as they moved out of the brain, through these channels, and into the skull bone marrow, where they discovered organized immune structures resembling those normally found in lymph nodes. Lymph nodes serve as important coordination centers for immune activity, and finding comparable structures in healthy bone marrow was unexpected.

Expert Commentary

Senior author Jonathan Kipnis, PhD, stated that the skull bone marrow is far more than just a structural framework and harbors previously unrecognized hubs for brain-specific immune responses. Kipnis added that uncovering this localized immune niche changes how we view neuroimmune interactions and opens exciting new avenues for treating brain tumors and other neurological diseases. First author Jang Hyun Park, PhD, noted that such structures have never been seen in healthy bone marrow before and that a complex brain requires its own specialized immune structures to defend it.