The findings have implications for how diseases with an immune component are researched and treated.
Most researchers spend their careers searching for the missing link in their respective field of study, but University of Virginia School of Medicine researchers have found it. They’ve directly linked the brain to the immune system via previously unknown lymphatic vessels.
The game-changing findings, published in June 2015 in Nature, will likely affect medical textbooks and how every disease with an immune component — from multiple sclerosis to Alzheimer’s — is researched and treated.
“We believe that for every neurological disease that has an immune component to it, these vessels may play a major role,” said Jonathan Kipnis, PhD, professor in the UVA Department of Neuroscience and director of UVA’s Center for Brain Immunology and Glia (BIG). “Hard to imagine that these vessels would not be involved in a [neurological] disease with an immune component.”
According to Neuroscientist News, the discovery was made possible by the work of Antoine Louveau, PhD, a postdoctoral fellow in Kipnis’s lab. The vessels were detected after Louveau developed a method to mount a mouse’s meninges — the membranes covering the brain — on a single slide so that they could be examined as a whole. After noticing vessel-like patterns in the distribution of immune cells on his slides, he tested for lymphatic vessels and there they were.
As to how the brain’s lymphatic vessels managed to escape notice all this time, Kipnis described them as “very well hidden” and noted that they follow a major blood vessel down into the sinuses, an area difficult to image. “It’s so close to the blood vessel, you just miss it,” he said. “If you don’t know what you’re after, you just miss it.”
The Lymph Loop
Most of what you know about the “immune system” is actually the work of the lymph system. In biological terms, the lymph system is an astounding network of fluid, organs, nodes and nodules, ducts, glands, and vessels that continuously and aggressively cleanse the system of waste matter. Millions upon millions of nodes — some no bigger than a pinhead, others the size of a lima bean — guard the passages into the body against the intrusion of destructive substances. Placed end to end in a straight line, all the lymph vessels in the body would cover a distance in excess of 100,000 miles, which could circle the globe four times!
There is actually three times as much lymph fluid in your body as there is blood. Except for cartilage, nails, and hair, your entire body is bathed in lymph. If you could somehow see a picture of the network of glands and nodes inside your body, you would see what looked like an extremely fine sheath of lace covering and saturating everything.
You can actually feel some lymph nodes where they are close to the surface of your skin — on the sides of your neck, under your chin, under your arms, and where your legs meet your torso. (If you would like to see some unusually large lymph nodules, look at your tonsils.)
Unlike the circulatory blood system, the lymph system carries fluid only away from the tissues. It picks up wastes from all the cells and, through an intricate series of processes, breaks them down and arranges for their elimination from the body. Every day, billions of cells in your body die off and form highly toxic substances in the process. Toxins are also built up from the residue of the approximately 70 tons of food that we eat in a lifetime. Then there are pollutants and irritants in the environment, in cleaning products and cosmetics, and in all the other things we put in, on, and around our bodies. The lymph system cleans it all.
The lymph system is also involved in producing white blood cells (lymphocytes) that seek out, capture, and destroy foreign substances — such as bacteria and other “invaders” — and remove them from the body. The circulation of lymph provides ample opportunity for toxins to come in contact with the surfaces of the body’s powerful cleansing cells (such as macrophages and lymphocytes). In fact, more than 99 percent of soluble toxins (called antigens) can be trapped by the body’s lymph nodes.
Lymph Facts at a Glance
- The lymph system is a network of fluid, organs, nodes and nodules, ducts, glands, and vessels that continuously and aggressively cleanse the system of waste matter.
- Millions upon millions of nodes — some tiny, some large — guard the passages into the body against the intrusion of destructive substances.
- Placed end to end in a straight line, all the lymph vessels in one body would cover a distance in excess of 100,000 miles (more than four times around the earth).
- There is three times as much lymph fluid in your body as there is blood.
- The lymph system is involved in the production of white blood cells (lymphocytes) that seek out, capture, and destroy foreign substances, such as bacteria and other “invaders,” and remove them from the body.
Read more about the lymphatic system in “Look After Your Lymph!”