Drugs used to treat rheumatoid arthritis could help relieve lung-related symptoms in long Covid, which can persist even two years after the infection, according to a new research.
While previous studies have looked at blood samples to understand long Covid better, in this study -- published in the journal Science Translational Medicine -- researchers looked at lung tissues of mice and humans.
The team, including researchers from the University of Virginia, US, found that contracting Covid-19 can cause changes to immune cells in the lungs, thereby promoting scarring and driving inflammation even after the initial infection has passed.
The persisting inflammation was found to contribute to long-lasting respiratory symptoms, such as cough and difficulty breathing, associated with long Covid.
The team said the anti-inflammatory effects of rheumatoid arthritis drugs, including baricitinib, may help in relieving these respiratory symptoms.
Rheumatoid arthritis is a chronic inflammatory condition affecting joints.
"Our study identified a root cause of the respiratory complication of long Covid by performing comparative analysis of both clinical samples and a relevant animal model," lead author Jie Sun from the University of Virginia said.
In the lung tissue samples, the researchers found that immune cells -- which usually help the body fight disease -- were having 'faulty, harmful interactions'.
They never stopped fighting, even after the initial infection had passed, they said.
According to the researchers, doctors may be able to break this cycle of inflammation using drugs already known to treat the harmful inflammation seen in patients with rheumatoid arthritis.
However, clinical trials testing the efficacy of these drugs in targeting the same inflammatory pathway in long Covid would be needed, they added.