Some survivors of COVID-19 carry worrying signs that their immune system has turned on the body, reminiscent of potentially debilitating diseases like lupus and rheumatoid arthritis, a new study has found.
At some point, the body's defense system in these patients shifted into attacking itself, rather than the virus, the study suggests. The patients are producing molecules called "autoantibodies" that target genetic material from human cells, instead of from the virus.
This misguided immune response may exacerbate severe COVID-19. It may also explain why so-called "long haulers" have lingering problems months after their initial illness has resolved and the virus is gone from their bodies.
The findings carry important implications for treatment: Using existing tests that can detect autoantibodies, doctors could identify patients who might benefit from treatments used for lupus and rheumatoid arthritis. There is no cure for these diseases, but some treatments decrease the frequency and severity of flare-ups.
"It's possible that you could hit the appropriate patients harder with some of these more aggressive drugs and expect better outcomes," said Matthew Woodruff, an immunologist at Emory University in Atlanta and lead author of the work.
The results were reported Friday on the preprint server MedRxiv, and have not yet been published in a scientific journal. But other experts said that the researchers who carried out the study are known for their careful, meticulous work, and that the findings are not unexpected because other viral illnesses also trigger autoantibodies.
"I'm not surprised, but it's interesting to see that it's really happening," said Akiko Iwasaki, an immunologist at Yale University. "It's possible that even moderate to mild disease may induce this kind of antibody response."
For months it has been clear that the coronavirus can cause the immune system to run amok in some people, ultimately wreaking more damage to the body than the virus itself. (Dexamethasone, the steroid President Donald Trump took after his COVID diagnosis, has proved effective in some people with severe COVID to tamp down this over-exuberant immune response.)