Research Reveals Exactly How Rogue Immune Cells Cause Multiple Sclerosis

In multiple sclerosis, rogue immune cells damage the myelin sheath, which is the fatty layer of tissue that protects neurons. Loss of the myelin sheath leads to damage of the electrical impulses that allow the central nervous system and other parts of the body to communicate with one another. This, in turn, leads to impairment of motor function, including speaking and walking. Symptoms can either be irregular – flare up, go away, and come back – or be progressive and worsen with time. MS is unpredictable and each patient with the disease is affected differently.

A recent study

In a study published in the journal Cell Reports, researchers explained how drug designers should focus on blocking the activity of rogue immune cells, which are responsible for attacking healthy neurons. The research team, led by authors Sarah Lutze from the University of Illinois at Chicago College of Medicine (under the guidance of Dr. Dritan Agalliu, assistant professor of pathology & cell biology at Columbia) and Sunil Gandhi from the University of California, Irvine, discovered two different ways in which immune cells overcome the blood-brain barrier in order to get to the neurons, attack them, and cause damage to the brain and spinal cord.

The specifics were misunderstood until now

While to date, it has been known that the activity of two different types of immune cells, Th1 and th17 lymphocytes, is known to cause damage to the myelin in MS, it was not clear to researchers how the cells were able to penetrate through to the blood-brain barrier and gain access to the neurons. The blood-brain barrier not only protects the brain, but it also protects the spinal cord and makes sure that the blood vessels that supply blood to both areas are impermeable. This is because the cells that make up the blood vessels, known as the endothelial cells, are bolted tightly together by protein complexes known as tight junctions. Tight junctions prevent harmful cells, chemicals, and microbes that are circulating in the blood from getting to the brain and spinal cord. In regards to the blood vessels that supply blood to other areas of the body, the endothelial cells are more loosely bound together. Therefore, this allows a freer transmission of cells, chemicals, and microbes from the bloodstream into the tissues and the other way around. “In autoimmune diseases like multiple sclerosis, immune cells that enter the brain and spinal cord cause disease. A better understanding of how these cells cross the blood-brain barrier will aid our efforts to develop specific therapies to keep them out,” said Lutz, lead author of the study and assistant professor of anatomy and cell biology in the UIC College of Medicine.

Read on to learn more about this study, its promising results, and what it could mean for the future of multiple sclerosis diagnosis and treatment.