Rare neuroimmune disorders are immune-mediated disorders of the central nervous system (brain, spinal cord and optic nerves). The immune system is the body’s defense against foreign invaders, such as viruses and/or bacteria. Normally, the cells that are a part of the immune system have the ability to distinguish an infectious agent from a person’s body; however, sometimes some of these cells become ‘confused’ and mistakenly attack an organ within a person. This is known as autoimmunity. Health care providers sometimes use the term ‘inflammation’ to describe this occurrence. Inflammation refers to situations when immune cells invade human tissue. For example, if there is inflammation in a spinal cord, then immune cells have invaded the spinal cord. Inflammation can be normal, such as during an infection, or abnormal, such as during autoimmune attacks.
The rare neuroimmune disorders that are supported by SRNA occur when a person experiences an inflammatory attack at some location in their central nervous system. When the spinal cord is affected it is called Transverse Myelitis (TM), and when the optic nerve is affected it is called Optic Neuritis (ON). In Acute Disseminated Encephalomyelitis (ADEM), MOG Antibody-Associated Disease (MOG-Ab disease), and Neuromyelitis Optica Spectrum Disorder (NMOSD) there are various patterns of organ involvement, and in some disorders there is the potential for recurrent events. When the central nervous system is affected, there are multiple kinds of damage that can occur. The connections between the brain and body are like insulated electrical wires. During an immune mediated attack on the central nervous system, the insulation around the wire (myelin) or the wire itself (axon) can be damaged. When an inflammatory attack damages the insulation, the damage is referred to as demyelination.
When the myelin or axon of a neuron is damaged, it is unable to conduct a signal. The symptoms are dependent on which axons are affected. For example, if the wire that carries visual information from the eye to the brain (optic nerve) develops demyelination, then signals are not carried to the brain efficiently resulting in a person having blurred or lost vision (ON). If the demyelination occurs in the wires sending motor signals to a person’s legs, then the person has weakness and difficulty walking.