13 msfocusmagazine.org damage. Speaking of the blood-brain barrier, we can actually see this “leaky” blood-brain barrier on MRI. When we give dye by vein during an MRI, if the blood-brain barrier is leaky,thedyecrossesitandresultsinMSlesions that “enhance.” This enhancement typically lasts for four to six weeks and then resolves. B-cells are cells of the immune system that have two major roles in inflammation. B-cellscanbecomeplasmacells,whichproduce antibodies.Antibodies are crucial in protecting us from foreign invaders like bacteria, but can also be problematic in autoimmune diseases like MS. Interesting, a class of antibodies called monoclonal antibodies are also used to treat MSandincludeTysabri(natalizumab),Lemtrada (alemtuzumab), Ocrevus (ocrelizumab) and Zinbryta (daclizumab). Finally, macrophages also play a role in the inflammatory damage of an MS relapse. Macrophage comes from the Greek words “makro” meaning big and “phagein” meaning to eat. So, macrophages are big eaters. Think of them as like a little Pac-Man, gobbling up bacteria or other undesirable things in your body. Again, in the setting of an autoimmune disease,thisnormallyhelpful cell can be turned against healthy tissue, such as myelin. Fortunately, the human immune system caneventuallyturnofftheimmuneattackofan MS relapse. Many people recover naturally and completely from an MS relapse. Steroid treatment may speed up the recovery process. Unfortunately, some relapses are not associated with a complete recovery and may lead to a newlevel of permanent disability.The number of relapses in the first two years after the diagnosis of MS is also important. More relapses in the first two years of MS are associated with a higher risk of needing a cane to walk sooner. Recovery from a relapse also involves the myelin and axons themselves.As humans, we do have some abilityto make newmyelin after it has been damaged. The new myelin tends to be thinner than the original equipment and may be more prone to damage from anotherattack. Even if newmyelin is not made, electrical conduction can be re-established across a demyelinated axon. This is done by spreading out sodium channels across the naked nerve fiber.While this does re-establish electrical signaling, this way of repairing the damage may lead to “conduction block” or “nerve fiber fatigue.” In everyday life, this means weakness, visual loss, sensory symptoms or other symptoms that happen with exertionorfatigue.It’simportant to remember that you are not causing any new damage if you overheat or exert yourself too much. You are simply draining the battery. Once you rest and cool off, things should be back to baseline. In terms of managing relapses, the best treatment is prevention. That’s the goal of any of the 16 available FDA-approved disease modifying therapies. If you do experience a relapse, decisions will need to be made about treating it with steroids or not, and whether any changes are warranted to your existing long-term therapy. In general, there are not many lifestyle factors that we think are associated with a higher risk of a relapse. Let’s look at a few though: Fortunately, the human immune system can eventually turn off the immune attack of an MS relapse. Many people recover naturally and completely from an MS relapse.