A small percentage of young and healthy people develop severe symptoms when infected with the corona virus. Two international studies in the journal Science explain for the first time in nearly 15 percent of those in their twenties why they become seriously ill. This can be the result of a hereditary abnormality or a defect in the immune system. The studies are an important step forward in treatment, says Professor Filpaal Haerynck of UZ Gent. The UZ participated in both studies and coordinated the data collection of seventeen Belgian centers.
Some young and healthy people get much sicker from COVID-19 than others in their age group. For example, there are people in their twenties without underlying conditions who need intensive care. Two studies show that the young people are deficient in a certain group of proteins. Proteins of the type I interferon, which protect the body against viruses.
The first study showed that many critically ill subjects tested carried rare variants of thirteen genes that are known to be crucial to protect the body against, for example, the seasonal flu virus. These genes regulate the production of type I interferons. More than 3 percent of them even lacked a functional gene. Further studies showed that the immune cells of these patients therefore did not produce detectable type I interferons during the acute COVID-19 infection.
Deviation in defense
A second study reveals another abnormality in the seriously ill infected patients. These people have certain antibodies or immune cells that, instead of attacking the enemy, attack their own immune cells. More specifically, the proteins of the type I interferon. A very small number of uninfected people (4 in 1,277) also have these types of defective antibodies. That is why the researchers think that the abnormality in the immune system is not the result of the infection with the corona virus.
“The research is an important step forward in deciphering the immunological treatment that we can provide to patients with COVID-19,” says Professor Haerynck, “We still need to test these treatments through clinical trials. But this is clearly a great example of how we can now consider known treatments for other diseases with COVID-19. ”
For example, treatment with type I interferons has been available and approved for a long time, for example in chronic viral hepatitis. Another possible treatment for patients with these abnormalities is plasmapheresis, a treatment to eliminate faulty antibodies from the blood, used for example in severe kidney disease.