)
Science just got closer to knowing the cause and treatment for multiple sclerosis. The disease consists of a degeneration of the central nervous system characterized by the gradual removal of the myelin sheath, which acts on neurons as an electrical wire cover. Consequently, the person suffering from the disease develops deficiencies in the senses, motor and cognitive functions. Multiple sclerosis is not usually life-shortening, but it is debilitating. Now, a new study in partnership with the US military that followed more than ten million officers on active duty during 20 years proposes a culprit for the disease: the Epstein-Barr virus.
The study, published in the journal Science on the day 13 in January and first shared by Kjetil Bjornevik and Marianna Cortese, both from the Department of Nutrition at Harvard’s TH Chan College of Public Health, noted how many military personnel infected between 1993 and 2022 with the virus, and, of those, how many developed multiple sclerosis. One of the difficulties is that it infects 95% of the population, but multiple sclerosis is a rare disease, affecting about one in every thousand people.
To get around the problem, the researchers first isolated the 5% of active-duty servicemen who showed no signs of infection with the Epstein-Barr virus, using blood plasma samples collected by the military to primarily measure infection with the Epstein-Barr virus. HIV. Epstein-Barr is a herpes-like virus that was already known to cause a number of illnesses such as infectious mononucleosis, a common illness in teenagers and college students characterized by extreme fatigue, fever, sore throat, headache and body aches, swollen glands in the neck and armpits, irritation and swelling in the liver and spleen. The virus also causes Hodgkin’s lymphoma and other cancers. Most of those infected do not develop these diseases.
Among the 5% of military personnel – the equivalent of hundreds of thousands of people in the sample -, were documented by the researchers 955 cases in which the multiple sclerosis emerged. In each of these cases, they tested the subject’s blood plasma up to three times. In the first, to establish the infection-free status, when the majority were below the 20 years old. Another test was performed shortly before the diagnosis of sclerosis, approximately ten years later, and another test was performed in the period between these two.
Each of the multiple sclerosis patients was compared with two disease-free individuals of the same age, sex, race, and military service specialty. These individuals served as controls. After method adjustments, the sample of individuals with sclerosis was reduced to 801. Of those, only one tested negative for the Epstein-Barr virus, in the second battery of tests, before showing symptoms of multiple sclerosis. This means that the risk of individuals with multiple sclerosis having the virus is four to 380 times greater than not having.
Detective work
Correlations are just a point of reference. starting point for scientists to suggest that the Epstein-Barr virus causes multiple sclerosis. Further investigations were carried out to ascertain a causal relationship. They investigated, for example, whether another herpes-like virus, cytomegalovirus (CMV), could be behind the disease. As it is from the same viral group, CMV serves as another type of control over the results. The presence of antibodies in the blood plasma of the military against CMV was not different between the group with multiple sclerosis and the group without the disease, unlike the antibodies against Epstein-Barr.
They also looked at a method that allows detecting antibodies against 214 species of viruses that infect humans, in addition to
a thousand different targets in these viruses for human antibodies, if any other virus stimulated a different immune system response compared to patients with multiple sclerosis with the disease-free. Only Epstein-Barr showed this difference.
Continuing the detective work , researchers look for a molecule associated with neurodegeneration in plasma, which may indicate the onset of multiple sclerosis long before the patient presents the clinical picture, and noticed that the molecule increased in the blood of military personnel up to six years before the diagnosis of the disease. This increase in the molecule happened shortly after infection with Epstein-Barr.
) There is a mutation in a human gene whose effect is to increase the risk of multiple sclerosis by three times. The researchers point out that this mutation is not associated with infection with this virus, and that the mutation may work together with the virus to cause the disease. So, by elimination, the study concludes that it is very unlikely that there is any other factor as important as the virus in explaining the causes of this neurodegeneration. Thus, there is a hope of avoiding the disease.
mRNA is hope to prevent multiple sclerosis
Bjornevik, Cortese and his colleagues comment that their discovery explains why one of the most effective treatments known for multiple sclerosis involves the administration of monoclonal antibodies that reduce the number of memory cells in the immune system. Antivirals that attack Epstein-Barr are already being tested as a treatment. To prevent multiple sclerosis, the same technology behind the mRNA vaccines against COVID could be used 19. An mRNA vaccine against the Epstein-Barr virus is already in phase 1 of development by the company Moderna. The year of 2022 starts with more hope for people with multiple sclerosis, with a great possibility that, in the future, the disease may be eliminated along with other problems caused by the virus.
