‘Missing link’ vessels connecting brain and immune system found

US researchers have made the discovery that the human brain is directly connected to the immune system by vessels that were not known to exist until now.

The University of Virginia study has revealed that the brain is connected to the peripheral immune system through meningeal lymphatic vessels, like all other tissue. The presence of a lymphatic system for the central nervous system was previously unknown since it follows a major blood vessel down into the sinuses, an area that is difficult to image.

It is expected that this discovery will greatly affect the study and treatment of a number of neurological diseases, including autism, Alzheimer's disease and multiple sclerosis, among others.

The team also believes it answers key questions about neuro-immune interactions that were previously thought to be unanswerable, allowing this process to be considered mechanistically for the first time.

Dr Jonathan Kipnis, professor at the University of Virginia department of neuroscience, said: "I really did not believe there are structures in the body that we are not aware of … I thought that these discoveries ended somewhere around the middle of the last century. But apparently they have not."