Last week, a study published in the prestigious journal Nature made waves in the scientific community with the discovery of a direct connection between the lymphatic system and the central nervous system (CNS). This finding was ground-breaking in that it provided concrete evidence that toppled the classically-held belief that the brain and spinal cord (together comprising the CNS) lacked lymphatic drainage and a direct link to the immune system, and unveiled a new avenue for exploring the disease-causing mechanisms of multiple sclerosis.
What is the lymphatic system, exactly? The lymphatic system is a network of vessels and organs in the body involved in both draining and filtering interstitial fluid (the fluid that bathes the cells of our tissues) back into the blood. In addition, the lymphatic system transports lymphocytes (a type of white blood cell) and antigen-presenting cells (APCs), which are both integral components of the immune system. During an infection, invading microbes are detected by APCs, which engulf the microbe and display pieces of them (called antigens) on their surface. The APCs travel to the lymph nodes (lymph organs distributed throughout the body) where they interact with lymphocytes that “recognize” the microbial antigen, causing the lymphocyte to activate and mount an immune response in order to fight the infection.