Neurologists from the University of Virginia School of Medicine has discovered a previously unknown link between the brain and the body's immune system, which could play a critical role in battling neurological conditions that include the likes of Alzheimer's disease and autism spectrum disorder in the future.

For the new study, researchers have found that the human brain is directly connected with the immune system by vessels that scientists did not previously know existed.

A 2009 research review has pointed out that it is an undisputed fact that the only major organ that does not have direct connection to the lymphatic system is the brain but the team discovered that the lymphatic system encloses the brain, which contradicts previous knowledge that the lymphatic system ends at the brain.

The lymphatic system is not part of the immune system but it has a crucial role in providing protection to the body against foreign and harmful microorganisms by carrying the fluid containing all the white blood cells, which fight these organisms and allow the body to excrete them.

The newly discovered vessels have surprisingly evaded detection regardless that the lymphatic system has already been thoroughly mapped.

Study researcher Jonathan Kipnis, from the University of Virginia's Center for Brain Immunology and colleagues noticed the odd object while studying the membranes of the mice's brains under the microscope and found that the lymph vessels hide behind another blood vessel located in the part of the brain that scientists have difficulty imaging.

The researchers said that although the observation was made on the brains of mice, the same anatomy characterizes humans as well.

"The unique location of these vessels may have impeded their discovery to date, thereby contributing to the long-held concept of the absence of lymphatic vasculature in the central nervous system," the researchers wrote in their study, which was published in the Journal Nature on June 1.

The finding is seen to have important implications in understanding diseases that plague the brain and the immune system. Kipnis said that the vessels may have a role in neurological diseases with an immune component to them.

The existence of the vessels, for instance, could explain why large protein chunks accumulate in the brain of people suffering from Alzheimer's such that these proteins may be accumulating because the vessels do not efficiently remove them.

The researchers likewise hope that the findings could pave way to the treatment of these disorders via therapies targeting the brain's lymphatic vessels. 

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