Inhibiting a protein associated with chronic inflammation improves lung health in mice with COVID-19.
Signalling molecule
A signalling molecule that helps to kick-start inflammation in the lungs could play a key part in aggravating some long COVID symptoms, finds a study that analysed lung samples from people with the condition.
By inhibiting the molecule — called interferon gamma (IFN-γ) — in mice with COVID-19, “we were able to dampen the chronic conditions after infection”, says study co-author Jie Sun, an immunology researcher at the University of Virginia in Charlottesville. “In the future, we could target this pathway for potential treatment of long COVID.”
Inflammation protein
IFN-γ is one of many proteins that the body releases to fight infections. When released by white blood cells known as T cells, it sends signals to other immune cells and promotes inflammation. In the short term, this increases blood flow to the infected area to support the healing process — but chronic inflammation can cause damage to cells and tissues.
To investigate this, Sun and his colleagues took a two-step approach. First, they recruited people with long COVID and compared samples of cells from their lungs with those of people who had recovered from COVID-19 a few weeks before the study, as well as a controls who hadn’t been infected.
Then, the researchers infected mice with SARS-CoV-2. Twenty-one days after infection, the mice had a cellular response in their lungs similar to that seen in people with long COVID, including elevated levels of IFN-γ-producing T cells.
Future treatments
The team hopes that targeting IFN-γ could have similar benefits for people with long COVID. “The next step would be to see if we can use a treatment which impacts this pathway to see if symptoms are improved in patients,” says Stéphanie Longet, an immunologist at the International Centre for Infectiology Research in Lyon, France, who has long COVID herself. She adds that there are already IFN-γ-inhibiting drugs on the market, such as baricitinib, which is currently used to treat severe COVID-19 and to reduce inflammation caused by rheumatoid arthritis.
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Source: Nature
