Common Arthritis Drugs May Help Dangerous Viruses Spread, Study Finds

"JAK inhibitors are often prescribed for autoimmune diseases and inflammatory conditions such as rheumatoid arthritis," says Erlend Ravlo, a PhD research fellow at NTNU and first author of the paper.

The drugs suppress an important immune signaling pathway that helps protect healthy cells from viral attacks. "In particular, the drugs suppress an important immune signalling pathway that helps protect healthy cells from viral attacks," Ravlo said.

When that pathway falters, the activity of antiviral genes drops.

"These genes play a crucial role in the body's response to viral infections," said Aleksandr Ianevski, an NTNU researcher and coauthor of the study.

Without the usual defensive response, viruses find it easier to establish an infection and move between cells.

How did the team test this?

The researchers combined advanced virology methods with gene expression analysis and organoid technology — miniature, lab-grown organ models that mimic real human tissue.

Their experiments covered cells from the lungs, eyes, and brain, allowing the team to track how JAK inhibitors affect antiviral defenses across different tissue types rather than in a single cell line.

"Although JAK inhibitors are effective in the treatment of inflammation, this shows that they can pose a hidden risk for patients who have latent or active viral infections," Ravlo says.

Takeaway: lab-grown tissue models from three organs showed the same pattern — the drugs removed barriers that normally hold viruses in check.

What does this mean for prescribing?

The results suggest clinicians should weigh the timing of JAK inhibitor prescriptions carefully, particularly when a patient already has a viral infection or when a virus is circulating widely in the community.

The researchers stop short of calling for anyone to stop treatment. The findings are preliminary in the sense that they come from laboratory models, not from clinical trials in patients, and the authors themselves frame their recommendation as a call for further study.

"We recommend further studies to better understand how the drugs can be used optimally, especially during virus outbreaks or pandemics," says Ianevski.

There is also a research upside. The same immune-suppressing properties that create risk in patients could help scientists under controlled laboratory conditions — for example, in developing vaccines or evaluating candidate antiviral drugs.

Who funded the work?

Professor Magnar Bjørås of the Department of Clinical and Molecular Medicine provided significant scientific expertise and secured most of the funding. Additional support came from the Central Norway Regional Health Authority, the South-Eastern Norway Regional Health Authority, the Research Council of Norway, and the Swedish Research Council.

For prescribers, the practical point is simple: JAK inhibitors work well against inflammation, but during an outbreak or an active infection, their antiviral cost deserves a second look.