Researchers at the University of Arkansas for Medical Sciences say they have discovered an antibody that may be the cause of long-term COVID-19 symptoms.
The study shows some patients who contract COVID-19 have responses where their bodies produce a second antibody called autoantibody. The antibody then attacks an enzyme called ACE2 that balances the body's response to the virus. When the second antibody attacks ACE2, it causes organs to not function properly.
Dr. John Arthur, director of nephrology at UAMS and one of the lead researchers, said he and his team focused on the enzyme because they estimated there was an increase in immune system activation.
“We got some samples from people that had been infected with coronavirus and recovered, and they were at least three weeks out from their infection. In another group, we got blood samples from people that had coronavirus infection,” Arthur said. “Then, we looked to see if they had antibodies against ACE2, and they do.”
In the findings, published in the Public Library of Science One, Arthur said about 80% of patients in the first group had antibodies against ACE2. The patients who never had the coronavirus also never produced the second antibody.
According to the study, some people with the autoantibody have severe long-term COVID-19 symptoms, and some don’t. Arthur said he and other researchers have a few ideas as to why this may be.
“It could be that the antibody is against different parts of the ACE2 enzyme, it could be that some people have much higher levels of the antibody, it could be the persistence of them. Maybe some people get rid of those antibodies pretty quickly, and some people, they persist on and cause symptoms. We’re not sure exactly what that is yet,” Arthur said.
The next step, he said, is to test if there is a correlation between those who have the antibody and people who have long-term symptoms after their COVID-19 infection.
If the findings are proven to be accurate, Arthur said it still won’t be definite because there are other intermediate things that need to be studied. But researchers would be closer to finding a treatment, he said.
“There’s a lot of people that I think are getting desperate,” Arthur said. “Their symptoms are going on for so long and they’re so debilitating. But, the word that I would like to pass on is that there is hope. We’re getting closer to finding a treatment for this, and people just need to hang in there and we’re going to get to that point.”
