Two studies suggest that the measles virus sneaks inside our immune cells to "erase their memories". We would thus be vulnerable to certain diseases again.
According to the World Health Organization, the number of measles cases has increased by more than 280% worldwide since 2018. The patients concerned have therefore fallen victim to the symptoms infection, but not only. Two new studies now confirm that the virus also takes advantage of this to "wipe the memory" of our immune system. This means that those affected may also find themselves at the mercy of secondary infections.
That the virus is able to enter the immune system, researchers have long been aware of. We know that the number of white blood cells is reduced. The workforce then recomposes once the virus has been fought. However, even then, the affected person may remain immunocompromised for years. These two new studies allow us today to better understand this "immune amnesia".
For the first study, blood samples from 82 unvaccinated Dutch children were taken. When a measles epidemic hit the country in 2013, 77 of them were infected. The authors compared samples before and after infection to determine how their immune systems evolved.
The researchers focused on a type of white blood cell called a B cell. When the body detects a pathogen, these cells produce proteins that "catch" the germ and destroy it. forward to another protein for destruction. The B cells then continue to develop these antibodies even after the pathogen is gone. This is why the body "remembers" said disease when it rears its head again.
However, researchers found that children infected with the virus lost many B cells trained to recognize common infections. These came back after about 45 days, but they were much less effective than the first ones.
Researchers in the second study focused on the antibodies themselves. Using a tool called VirScan, they sought to determine which antibodies appeared in children's blood before and after measles. It emerged that after catching the virus, the children had lost between 11% and 72% of their total antibody diversity. In other words, the measles had erased much of their "immune memory".
The researchers point out that we could still recover some of it by reacquainting ourselves with the pathogens. The idea is therefore to re-educate our immune system.
Healthy people should be able to do this without too much trouble, but weaker or really immunocompromised patients might not be able to cope. “Getting bombarded by multiple infections at once could be particularly devastating “, conclude the researchers.
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