Measles erases the "memory" of our immune system

Measles erases the “memory” of our immune system


Two studies suggest that the measles virus sneaks inside our immune cells to “erase their memories”. We would be vulnerable again to certain diseases.

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 been victims of the symptoms of infection, but not only. Two new studies confirm today that the virus also benefits to “erase the memory” of our immune system. This means that those affected can also be at the mercy of secondary infections.

That the virus is able to get into the immune system, researchers have been aware of it for a long time. We know that the number of white blood cells is reduced. The numbers are then recomposed once the virus has been fought. However, even in this case, the affected person may remain immunocompromised for years. These two new research allow us today to better understand this “immune amnesia”.

New, less effective “soldiers”
For the first study, blood samples from 82 unvaccinated Dutch children were collected. When a measles outbreak hit the country in 2013, 77 of them had been infected. The authors compared samples before and after infection to determine the evolution of their immune system.

The researchers had focused on one type of white blood cell called cell B. When the body detects a pathogen, these cells produce proteins that “catch” the germ and pass it on to another protein for destruction. B cells then continue to develop these antibodies even after the disappearance of the pathogen. This is why the body “remembers” the said disease when it points again to the tip of its nose.

However, researchers found that children infected with the virus had lost many B cells trained to recognize common infections. They returned after about 45 days, but they were much less effective than the first ones.

“Amnesic” defenses
The researchers in the second study focused on the antibodies themselves. Using a tool called VirScan, they sought to determine which antibodies appeared in the blood of children before and after measles. It was found that after catching the virus, children lost between 11% and 72% of their total antibody diversity. In other words, measles had erased much of their “immune memory”.

The researchers point out that we could still recover some of it by familiarizing ourselves again with the pathogens. The idea is to re-educate our immune system.

People in good health should be able to do this without much problem, but weaker or really immunocompromised patients may not be able to cope. “Being bombarded with several infections at once could be particularly devastating,” the researchers conclude.