Wed. Jan 26th, 2022


In green, leukemia cells are infected by Epstein-Barr virus.

In green, leukemia cells are infected by Epstein-Barr virus.
Pictures: CDC / Dr. Paul M. Fiorino

Scientists say they have found significant evidence that a common infection caused by Epstein-Barr virus is the leading cause of multiple sclerosis. Them Research It was found that military personnel who tested positive for the new virus did not have a higher risk of developing multiple sclerosis later than those who did not. The results appear to support the need for a preventive vaccine or treatment that can directly target a lifelong latent infection.

Multiple sclerosis is a rare but debilitating Brain deformity Which affects an estimated 1 million people in the United States who have multiple sclerosis have an over-stimulated immune system that eats away at the protective lining of our nervous system, known as myelin. Over time, myelin deficiency slows down and damages the connections between our brain and body, leading to a range of symptoms such as numbness, muscle weakness, pain, and difficulty walking.

Multiple sclerosis Is proceeding differently After the initial exacerbation from person to person, and most people can avoid the symptoms early on and clear up the nerve damage for months or years at a time between re-infections. But about 10% to 20% of those with multiple sclerosis have to live with stable and often worsening symptoms, with some relapsing forms of multiple sclerosis eventually ending in remission. In the most severe cases, people lose their ability to write, speak and walk, and even the average sufferer’s life expectancy is reduced.

There is no clearly established cause for MS, although it has long been suspected that some viral infections may be the primary trigger in many cases. And has been one of the most prominent suspects Epstein Barr virus (EBV).

EBV is a herpesvirus that almost everyone contracts at some point in their lives. Infection does not usually make children sick, but if caught during adolescence or adulthood, it is one of the leading causes of infectious mononucleosis, or psycho-an acute illness that causes fatigue, fever, and sometimes about two to six rashes. Weeks after the initial illness, however, the virus then remains dormant in our body and usually does not cause visible problems again, although it can do so in people with weakened immune systems.

Some evidence suggests a link between EBV and multiple sclerosis, including finding signs of EBV in lesions caused by the disease. But a big hurdle in establishing an obvious cause-and-effect relationship between the two is that since EBV is so common, it can be difficult to find people before they become infected and track them over time to see if they develop MS, and Comparing those who are not infected with the virus to those at risk. It’s new Research, Published in Science on Thursday, seems to have done it.

The research team, led by scientists at the Harvard TH Chan School of Public Health, was able to track the long-term health of nearly 10 million active-duty military members over a 20-year collaboration with the U.S. military. At the beginning of their service, these members have their blood tested for HIV and screened regularly every two years. This means that researchers can test the same blood samples for EBV.

During the 20-year study period, 955 people were diagnosed with multiple sclerosis during their service. Of the 801 MS cases that had test blood samples, only one tested positive for EBV antibody. The team also looked at thirty-five people who later developed multiple sclerosis but who were negative for EBV early in their military service, and compared their controls with those who tested negative for the virus and did not develop multiple sclerosis. All but one of them were infected with the virus before their final MS diagnosis. In contrast, the people in the control group Those who never developed MS were also less likely to be diagnosed with EBV during the study period.

According to study author Mariana Curtis, those who contracted the virus had a 32 times higher risk of developing MS than those who avoided the infection – so much so that it was a mere coincidence and incredibly unlikely. That “provides compelling evidence of causation,” he said in an email.

“This level of risk is unusual in scientific research. The strength of these results and the study and other aspects of the results indicate that this cannot be explained by other risk factors and makes us confident that EBV is the leading cause of MS, “added Cortes.

Using the same blood sample, Curtis and his team were also able to detect the presence of markers associated with neuroaxial degeneration, a sign of MS that may be present long before symptoms occur. And again, they found that these markers in MS patients were initially negative for EBV, only to be seen after the virus had infected them, further supporting an effective link. They also failed to find a similar link between MS and human cytomegalovirus, another very common herpesvirus, suggesting that there is something really important about the role that EBV plays in multiple sclerosis.

Although EBV is very common, multiple sclerosis is very rare, perhaps because other important factors, including genetics, affect someone’s risk. A case of MS has been found in someone without a previous EBV infection, which may mean that other infections are less common triggers. But the results of the study, assuming they have been verified by other studies, have some important implications for how we are advancing EBV.

“If EBV is the leading cause of MS, the disease can be prevented by preventing EBV infection, for example with a vaccine,” Cortes noted. “Also, targeting the virus with EBV-specific drugs may lead to better treatment of the disease.”

This will not be the first vaccine made for a germ to prevent a separate but connected condition down the road. The HPV vaccine is already available Begins to resist Many cases of cervical cancer are among the first women to get it.

There is also some evidence that latent EBV infection can affect the course of MS symptoms. Currently, one of the most effective treatments for multiple sclerosis Monoclonal antibody, CD-20 Which reduces the body’s supply of memory B cells that can attack the nervous system. But these cells are also where the EBV is hidden, so it is possible that some of the benefits of these drugs can get rid of the EBV. And if that is the case, then making antivirals that can directly target EBV may be a better strategy than these antibodies, which are given intravenously and weaken the immune system.



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