The serious symptoms associated with COVID-19 come not from the virus itself, but from our immune system, according to a recent study published in the journal Nature. White blood cells, these cells supposed to protect us against microbes, would even become a “Trojan horse” likely to cause the destruction of our organs.
Two types of white blood cells are targeted by this study published in the journal Naturemacrophages in the lungs and monocytes in the blood.
These “monocytes” would be particularly responsible for the “inflammatory cascade” which damages our lungs, our muscles and our heart, and which can lead to death. Normally, these monocytes absorb microbes and then destroy them.
However, the COVID-19 virus would have the ability to survive this absorption, and even to use these white blood cells to reproduce. “This is a surprising finding, as it shows that [globules blancs] can promote infection,” the article states.
What should fight against the disease on the contrary spreads it, confirms Dr. Donald Vinh, a specialist in infectious diseases associated with McGill University. ” The problem is that [les monocytes] circulate in our blood, and therefore in our organs. It becomes a kind of Trojan horse to get to the entry point of other organs, like the brain, the liver, or whatever, and facilitate the distribution of the virus. »
Once the virus is present everywhere in the body, our immune system has no choice but to bring out the heavy artillery to get rid of the intruder. This immune counter-attack then takes the form of self-destruction.
“The immune system tries to use a bazooka rather than a gun to kill infected cells en masse,” Dr. Vinh explains. […] When the virus starts to spread, we have to increase our response. And there, we lack precision. We don’t just target the infected cells, but also the cells around them. And that’s why we have organ damage. »
What is “scary” about this discovery, he adds, is the impossibility of stopping this “inflammatory cascade”, because “interrupting this process of inflammation in the monocyte helps the virus to reproduce”.
Current treatments still manage to partially curb the runaway immune system, and this study confirms a little more the need for “strategic” drugs, believes the Quebec immunologist. “If we can understand this infection process, it can allow us to understand a little bit more about the effectiveness of our drugs. »
This text is taken from our newsletter “Coronavirus mail” of April 11, 2022. To subscribe, click here.