Immunology and Multiple Sclerosis

Multiple sclerosis occurs when the immune system mistakenly attacks myelin, the protective coating around nerve fibers. In MS, immune cells become overactive and move into the central nervous system, where they trigger inflammation and damage myelin. This damage interferes with the brain’s ability to send signals properly.

Research shows that in the early stages of MS, immune cells called B cells and T cells drive the response against myelin. B cells and T cells are part of the adaptive immune response, which is the part of the immune system that is supposed that recognize, eliminate, and remember previously encountered germs. In MS, the B cells and T cells, remember and attack myelin on accident. This is usually due to a break down in the cells and signals that control immune responses. As the disease gets worse, other immune cells and immune signaling molecules called cytokines become involved, leading to inflammation that further breaks down myelin and injures the cells that produce it.

Scientists still do not fully understand what causes the immune system to behave this way, but genetic and environmental factors play important roles. Studies suggest that people with MS often have an imbalance between immune cells that encourage inflammation and those that normally keep inflammation under control. This imbalance allows the long-lasting inflammation that leads to the damaged myelin seen in MS. These immune responses create a cycle of injury within the brain and spinal cord that can lead to symptoms such as numbness, vision problems, fatigue, and difficulty with coordination.

What’s Next for Multiple Sclerosis?

Immunology research may hold the key to developing a cure for multiple sclerosis or new treatments that prevent the disease from worsening. In 2017, the United States Food and Drug Administration approved the first treatment for multiple sclerosis. The drug reduces the number of B cells in the body, one of the immune cells that attacks myelin.

Epstein-Barr virus (EBV) is common virus that infects many people in their lifetime. For reasons we don’t understand, in some people EBV may trigger autoimmunity, including MS. New research is investigating whether a vaccine against EBV could be used to treat MS. While this trial isn’t looking at whether the vaccine prevents EBV (other research is doing that), the HORIZON trial is seeing if this vaccine could help the immune system keep EBV under control after infection, which could decrease MS symptoms.