A study by French researchers published this week in the American journal Science shows that a deficiency in the blood of a protein normally produced by the immune system – interferons – “could be the hallmark of the severe forms of Covid-19”. A result that could help identify patients at risk.
Interferons are proteins of the cytokine family, produced in particular by cells of the immune system in response to the presence of an infection.
About 5% of people with Covid-19 progress to a severe or critical form, often occurring 9 to 12 days after the onset of the first mild to moderate symptoms. Researchers believe that this worsening is caused by a sharp increase in cytokines, which causes a runaway of the “inflammatory response” of the body. But doctors cannot say precisely which patients will develop this serious form of the disease, beyond the risk factors observed (diabetes, obesity, advanced age, etc.). But this is “an essential question […] to improve individual care and the prognosis of these patients “, observe the authors.
These performed analyzes on 50 patients, with different degrees of severity. It appears that in seriously ill patients, “the production and activity of type 1 interferons are greatly reduced”. They also have a persistent viral load in the blood, testifying to the poor control of viral replication by the immune system.
A new therapeutic approach?
The study also reveals that “low levels of type 1 interferons in plasma precede the clinical worsening of patients and their transfer to intensive care.” Therefore, type 1 interferon deficiency “could be a signature of the severe forms of Covid-19 and could help identify a high-risk population”. Furthermore, these results “underline the interest of therapeutic approaches associating the early administration of interferons with an adapted anti-inflammatory therapy.”
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