How the KIR4.1 Autoantibody Could Change the Diagnosis and Treatment of MS
A team of scientists from the University of Munich recently published a paper in the New England Journal of Medicine reporting that they may have found an autoantibody linked to multiple sclerosis. The results of their research were recently presented at the American Academy of Neurology’s 66th Annual Meeting in Philadelphia, PA. In their study they found that almost half of people with MS had detectable levels of the KIR4.1 autoantibody in their blood years before developing MS. During the study they tested the blood of 16 blood donors who later developed MS for the KIR4.1 autoantibody and found that 7 people tested positive, 2 were borderline and, 7 were negative. Additionally, autoantibodies were not present in any of the blood samples taken from healthy people. So what is KIR4.1 and what does this mean to the MS community?
Despite its complicated sounding name, KIR4.1 is simply a protein. In humans proteins are essential molecules and they are involved in almost every process within our bodies. There are hundreds of thousands of proteins in the human body, and each one has its own job. The KIR4.1 protein is essential in the formation of myelin, and our brains need KIR4.1 in order to make the myelin that forms the protective covering around our nerves. A normal, healthy immune system fights off infections and foreign invaders with weapons known as antibodies. However, in some people, the immune system malfunctions. If your immune system mistakenly attacks your own proteins or cells thinking they are foreign invaders, then the antibodies used to attack them are called autoantibodies. This is what causes autoimmune diseases where your body attacks itself and is responsible for many different diseases. MS is a complicated autoimmune disease, and the team from the University of Munich has convincing data that suggest autoantibodies against KIR4.1 play an important role in the inflammatory process and tissue damage that occurs with MS.
Knowing that KIR4.1 autoantibodies exist and play a role in MS could help doctors in a couple of ways. First, it would allow us to have a blood test for MS. When we are doing other diagnostic studies such as lumbar punctures and MRIs, we can also test for the presence of KIR4.1 autoantibodies in the blood. But, according to the study not all MS patients have these antibodies. Knowing this could allow us to not only classify MS as relapsing remitting or progressive, but also as “autoantibody positive” or “autoantibody negative”. This could help us choose medications that will work better for each individual patient. Other diseases have similar autoantibodies that have helped in finding effective treatments. Myesthenia Gravis (MG) is an example of a neurological disease that we treat based on the presence or absence of autoantibodies. MG has many subtypes including autoantibody negative and autoantibody positive. The patient is then treated with different medications based on their subgroup to get the best results. The hope is that we will be able choose the best medications for MS patients based on autoantibodies such as KIR4.1. If MS really does have different subgroups this could help explain why MS is so different from patient to patient, and why certain medications work for some but not others.
The big question is how long are KIR4.1 autoantibodies detectable in the blood before someone develops MS? Knowing the answer to this question could help us identify “pre-MS” and may even let us intervene before the disease develops and or before it has the chance to cause significant damage. Larger studies will be needed to know for sure.1-5
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