Skull bone marrow contains immune hubs that fight brain cancer

Researchers at Washington University School of Medicine in St. Louis have discovered lymph node-like structures in the skull bone marrow of mice for the first time and demonstrated that they act as rapid first responders against brain cancer before distant lymph nodes get the signal that abnormal cells are present. The researchers also found evidence of similar immune cells in human skull bone marrow.

For decades, scientists assumed that the brain and the immune system did not communicate. The new study reveals that the brain not only communicates with the immune system but also has positioned immune 'security stations' nearby, closer than other organs do.

"This study reveals that the skull bone marrow is far more than just a structural framework - it harbors previously unrecognized hubs for brain-specific immune responses," said senior author Jonathan Kipnis, PhD, the Alan A. and Edith L. Wolff Distinguished Professor of Pathology & Immunology and a BJC Investigator at WashU Medicine. "Uncovering this localized immune niche changes how we view neuroimmune interactions and opens exciting new avenues for treating brain tumors and other neurological diseases."

Kipnis' lab challenged the once widely accepted idea that the brain is shielded from the immune system when they discovered lymphatic vessels running through the dura mater, the outer tissue layer enveloping the brain underneath the skull. More recently, his team identified tiny physical channels bridging the skull, dura and brain tissue, revealing a direct conduit for immune cells and cellular waste to move between the brain and local skull bone marrow.