For multiple sclerosis found a viral cause

Multiple sclerosis remains in many ways a mysterious disease in the sense that it is not very clear why it occurs. The disease process itself is well understood – it is an autoimmune attack on the myelin sheath of neurons. The myelin lipid sheath, which envelops neuronal processes in several layers, is needed to ensure that neural impulses are transmitted quickly and to the correct address. Without it, the connection between the nerve centers in the brain, between the brain and muscles, between the brain and the sense organs, literally disappears; inflammation that develops during an immune attack destroys the neural processes themselves. Accordingly, in the treatment of multiple sclerosis, they try to somehow suppress the excessive activity of the immune system or somehow distract the immune system from the destruction of myelin on neurons.

But why does the immune system begin to behave this way? There is evidence that it is a matter of genetic predisposition, there is evidence that it is some kind of infection, there is evidence that the manifestations of multiple sclerosis are highly dependent on the environment. Employees Harvard University write to Science that they were able to discover the main or at least one of the main causes of multiple sclerosis is the Epstein-Barr virus, or human herpes virus type 4. It is called one of the most common human viruses in general. For most, Epstein-Barr virus infection is asymptomatic, for some it can cause very serious trouble: it causes infectious mononucleosis, it provokes some cancers, hypothyroidism and chronic fatigue syndrome are associated with it.

Actually, they have also been talking about multiple sclerosis in connection with the Epstein-Barr virus for a long time. But it is difficult to establish a reliable causal relationship here: a viral infection is usually transferred in childhood or adolescence, while the first symptoms of multiple sclerosis, if they occur, then about ten years later. However, this time the researchers claim that they were able to establish a causal relationship, and succeeded thanks to more than 10 million military personnel, from whom the special medical service took blood samples every two years for several years – in total, about 62 million samples.

To see an association between Epstein-Barr virus and multiple sclerosis, the first sample must show evidence of a viral infection (eg, antibodies to the virus), and by the last blood sample, the same person must already have clear symptoms of the disease. This is exactly what happened: the virus increased the likelihood of multiple sclerosis by 32 times, and a couple of years before the onset of symptoms, a special protein appeared in the blood, which clearly indicates degenerative processes in the nervous system provoked by an autoimmune attack. For comparison, we tried to analyze the relationship of multiple sclerosis with another common and usually asymptomatic herpes virus, cytomegalovirus. But it apparently has nothing to do with multiple sclerosis: there could be a lot of antibodies to human cytomegalovirus, there could be little, this did not affect the likelihood of molecular signs and symptoms of multiple sclerosis.

True, as the portal writes The Scientist, cytomegalovirus is not a very good object for comparison here: there is an interesting medical statistic that suggests that cytomegalovirus infection partly protects against multiple sclerosis. And in any case, if you look at the prevalence of the Epstein-Barr virus, the question arises why there are so few cases of multiple sclerosis: it happens in about 0.5% of those who get the virus. Obviously, it is not the only main reason here, but one of the main reasons, and in addition to the virus, a person must have, for example, an overly excitable immune system, which, irritated by the virus, will begin to attack the body itself.

Source: Автономная некоммерческая организация "Редакция журнала «Наука и жизнь»" by

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