A pair of new studies on COVID-19 patients have found that the coronavirus is more deadly to some patients than others due to some having a previously unknown antibody. The findings could potentially help scientists and doctors identify highly vulnerable patients early on and develop targeted therapies to save lives—at a time when COVID-19 cases are skyrocketing across the U.S. and hospitals are filling up quickly.
In a study published in Science last month, researchers found that about 10 percent of nearly 1,000 COVID patients who developed life-threatening pneumonia had antibodies that suppress key immune system proteins called interferons. These antibodies were significantly less present among people with mild or no symptoms, although scientists found no evidence showing that the severity of symptoms had a role in the body generating these antibodies.
These antibodies are called “autoantibodies” because they attack the body itself. They are created when the body is attacked by autoimmune diseases, such as Lupus and Type 1 diabetes. In Type 1 diabetes, for example, a confused immune system fights viruses by attacking insulin-producing cells in the pancreas.
When a patient has these autoantibodies, their body is unable to generate interferons, which defends the immune system by activating virus-fighting genes. They are particularly important for protecting the body against new viruses, such as COVID-19.
When infected by the coronavirus, “your body should have alarms ringing everywhere,” Qian Zhang, a lead author of the study, told Kaiser Health News. “If you don’t get the alarm out, you could have viruses everywhere in large numbers.”
One surprising finding of the study is that an overwhelming majority of patients with these autoantibodies were men. About 12.5 percent of men who had developed COVID pneumonia had autoantibodies against interferons. Only 2.6 percent of women had the same autoantibodies.
This may have something to do with the difference in the number of genes on the X chromosome between men and women, researchers found. Men only have one copy of this chromosome, while women have two, which gives women a backup in case one copy of a gene becomes defective.
The study was led by the COVID Human Genetic Effort, which includes 200 research centers in 40 countries.
In another study by the same team published in Science last month, researchers found that an additional 3.5 percent of severely ill COVID-19 patients had mutations in genes that control the interferons.
Scientists need to confirm these findings in a much larger study. But these preliminary results offer valuable insights on the diagnosis of COVID-19. For instance, knowing that patients with the autoantibodies are more likely to develop severe symptoms, hospitals can test patients for the antibodies upon admission to identify high-risk groups. The findings could also help doctors develop targeted interferon treatments for those patients to lower death rate.