A new study by French researchers shows that a deficit in the blood of the Type 1 interferon protein “could be the hallmark of severe forms of Covid-19,” findings that could help in identifying patients at higher risk of becoming gravely ill.
Interferons are proteins from the cytokine family that are normally produced by the body’s immune system’s cells when it is infected.
About 5% of people infected with Covid-19 become gravely or critically ill, developing severe pneumonia which then becomes an acute respiratory disorder syndrome, often 9 to 12 days after the first light or moderate symptoms appear.
Researchers think this deterioration is caused by a strong increase in cytokines, causing the body’s inflammatory response to go into overdrive. However, doctors cannot tell for sure which patients will develop the severe form of the illness, beyond risk factors like diabetes, obesity and old age that have already been identified.
Knowing this is essential to improving individual care and patients’ prospects, Inserm, University of Paris, the Imagine Institute, Public Assistance – Hospitals of Paris (AP-HP) and the Pasteur Institute said in a press release on Thursday.
The authors of the study, who came from these institutions, ran tests on 50 Covid-19 patients with varying degrees of severity.
The results show that the production and activity of interferons was greatly diminished in severely ill patients. They also had a persistent blood viral load, attesting to poor control of viral replication by the patient’s immune system, leading the inflammation response to go into overdrive, and become ineffective and pathological.
The study published this week in the U.S. magazine Science also shows that weak Type 1 interferon levels in plasma precede the clinical deterioration of patients and the need to transfer them to intensive care, which means they could be a sign of severe forms of Covid-19 and could enable high–risk populations to be identified.
Further, the results show the interest of therapeutic approaches combining early management of interferons with an adapted anti-inflammatory strategy in patients, to avoid a severe form of the disease, the researchers say.