Antibodies that act like enzymes may explain some of the mystifying symptoms associated with COVID-19, early findings from a study of patients’ blood samples suggest.
In the analysis of blood samples obtained from 67 volunteers with moderate or severe COVID-19 on day 7 of hospitalization, researchers found a small subset had antibodies that acted like enzymes that regulate blood pressure.
Patients may also be making antibodies that activate enzymes involved in blood clotting and inflammation, the researchers said.
Typically, antibodies recognize and attack viruses and bacteria, while enzymes initiate or accelerate various processes in the body. Molecules called “abzymes,” which can perform both functions, have been seen before in patients with immune system disorders, according to a report in the American Society for Microbiology’s mBio.
When the virus that causes COVID begins to infect a cell, the spike protein on the surface of the virus attaches itself to an enzyme on the cell surface called ACE2. Some patients make antibodies against the spike protein that so closely resemble ACE2 that they also have enzymatic activity like ACE2, the researchers found.
Unfortunately, the researchers were not able to track their volunteers over time and so could not determine whether the abzymes were associated with patients’ clinical course.
“If COVID-19 patients are making abzymes, it is possible that these rogue abzymes could harm many different aspects of physiology,” study leader Dr. Steven Zeichner of the University of Virginia School of Medicine said in a statement.
“If this turns out to be true, then developing treatments to deplete or block the rogue abzymes could be the most effective way to treat the complications of COVID-19.”
