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For decades, researchers suspected that people infected with Epstein-Barr, an extremely common virus, may be more likely to develop multiple sclerosis, a neurological disease that affects. one million people in the United States. Now, a research team says it’s the most convincing evidence, some say, of a strong link between the two diseases.
The virus affects nearly everyone during their teen or young adult years, and very few go on to develop multiple sclerosis. The researchers also note that it is not the only known risk factor for people who develop the disease. However, they say their data indicates that it is clearer than any of them. While it remains to be seen whether the finding will result in a cure or cure for multiple sclerosis, the study could further motivate research into therapies and vaccines for the condition.
In his studies, Published Thursday in the journal Science, the group analyzed data from 10 million people who had been on active duty for two decades in the United States Armed Forces. D., an epidemiologist at the Harvard TH Chan School of Public Health. Alberto Ascherio said the strength of their work is that they can follow people for years and ask Epstein-Barr whether infections precede multiple sclerosis.
Among service members in the study, 801 developed multiple sclerosis, a disabling disease that occurs when the immune system attacks the fatty insulation that protects the nerves in the brain and spinal cord. Most people who develop the disease Diagnosed between the ages of 20 and 50. While the disease is rare – an individual’s chance of getting multiple sclerosis is half to one percent.
At the same time, the Epstein-Barr virus in question is widespread and infects almost everyone in the population at some point. While few realize they are infected, some develop mononucleosis. The virus remains in the body for life.
Since very few people infected with the virus have multiple sclerosis, it cannot be the only cause of the disease. Other risk factors have been identified, including some previously seen by the Harvard group using the same dataset, such as low vitamin D levels and smoking. There are genetic factors as well—Dr., a multiple sclerosis specialist at the University of Chicago who was not involved in the new study. Anthony J. Reder said that 900 abnormal genes have been identified in patients with multiple sclerosis. Gender also plays a role; Most of the patients are women.
However, Dr. Ascherio said no risk factors such as Epstein-Barr infections stood out.
To ask how much the virus raises risk, the researchers studied a small proportion of people who were not infected early in their service careers but were later infected. They detected infections by the presence of antibodies to the virus.
Among multiple sclerosis patients, 32 out of 33 were infected with Epstein-Barr before they developed MS.
As a control group for their study, the scientists followed 90 people who were not initially infected with Epstein-Barr and also did not get multiple sclerosis. Of these, only 51 subsequently became infected with Epstein-Barr.
Dr. Ascherio said this means that an Epstein-Barr virus infection increases the risk of multiple sclerosis more than 30 times.
However, Dr. Reder cautioned that it can be difficult to draw cause and effect from an epidemiological study. People who develop multiple sclerosis have overactive immune systems that make them develop high levels of antibodies against viral infections. Multiple sclerosis can occur not because of the virus, but because of the body’s response to it.
“Multiple sclerosis patients have fewer viral infections than normal,” he said, because their immune systems are so active that they fight viruses effectively. “Multiple sclerosis patients often say, ‘I never get a cold’. My ears are ringing when I hear that.”
Dr. Reder noted that the drugs currently used to treat multiple sclerosis suppress the immune system. He added that until now, anti-viral drugs have not helped people with multiple sclerosis.
The Harvard group sought to check for the possibility that in those infected with Epstein-Barr, the immune system response, not the virus itself, increases the risk of multiple sclerosis. They asked whether antibodies to another common virus, cytomegalovirus, were also linked to a greater risk of multiple sclerosis. They weren’t.
However, Dr. Reder said that cytomegalovirus protects against multiple sclerosis for unknown reasons. Therefore, it may come as no surprise that those infected with it do not have a higher risk of multiple sclerosis.
Others said the study had compelling evidence of cause and effect.
A multiple sclerosis specialist at Johns Hopkins, Dr. “The way it’s done is pretty convincing,” said Michael David Kornberg. “The most convincing data we have for a truly causal relationship.”
That leaves the question of what to do now.
A multiple sclerosis researcher at the University of California, San Francisco, Dr. Bruce Cree noted that it may be difficult to treat multiple sclerosis by following Epstein-Barr, as it can be difficult to find the actual virus in patients. Although multiple sclerosis is a brain and spinal cord disease, it did not find the virus in patients’ spinal fluid.
But patients seem to have cells in their brains that produce antibodies to the Epstein-Barr virus. Dr. Cree is investigating whether he can cure people with multiple sclerosis by destroying Epstein-Barr-infected cells.
And a multiple sclerosis researcher at Stanford, Dr. Lawrence Steinman perspective An experimental mRNA vaccine against Epstein-Barr is one of a number of approaches designed to stop the virus from infecting the brain, said Epstein-Barr, who accompanied the Harvard group’s article.
Now the question is, “Can we eliminate multiple sclerosis?” said.
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