The presence of special immune system defense molecules, known as autoimmune antibodies, has been strongly linked to people faring poorly when hospitalized with COVID-19. A new study by scientists at NYU Grossman School of Medicine examined the autoimmune antibodies in the blood of over 33% of adults admitted to the hospital and confirmed to have COVID-19.
The study found that a subset of the autoimmune antibodies that bind to DNA or to a specific type of fat molecule, phosphatidylserine, were twice as abundant during the initial phase of an infection in people whose symptoms worsened quickly than in those whose health did not worsen. Patients with these elevated levels of autoimmune antibodies were five to seven times more likely to develop severe disease than those whose antibodies levels were stable.
People hospitalized with severe cases of COVID-19 required mechanical ventilators and intensive care to help them breathe. The people with lower levels of the autoantibodies could breathe on their own and recovered.
Published in the journal Life Science Alliance on September 9, 2021, the researchers’ work is based on the nature of antibodies – immune proteins that target invading viruses and bacteria. Autoimmune antibodies attack the infected person’s own cells and molecules. This includes genetic material and lipids, or DNA, which can enter the bloodstream as cells while cells are being killed by a disease like COVID-19.
“Our study results show that initial blood levels of anti-DNA or anti-phosphatidylserine antibodies were directly linked to the severity of illness in those with COVID-19,” says study co-lead investigator Claudia Gomes, Ph.D., a postdoctoral fellow at NYU Langone Health.
“While further testing is needed, our findings suggest that a test for the presence of anti-DNA and anti-phosphatidylserine antibodies could help identify those COVID-19 patients admitted to hospital who are most at risk of needing intensive care and who need to be monitored more closely,” says Marisol Zuniga, MS, also a study co-lead investigator at NYU Langone.
This new study investigated the medical records and blood tests from 115 adults hospitalized at NYU Langone hospitals between April and June 2020. Approximately equal numbers had severe disease from which they either survived or died or did not require intensive care and recovered quickly. Test results for more than 100 measurements, such as blood oxygen levels, liver enzymes, and kidney function, were compared with levels of autoimmune antibodies.
The study was designed to analyze whether common autoimmune antibodies were present in COVID-19, which other studies have found in other infectious diseases. It also looked at whether variations in the blood levels were related to how sick people became.
Thirty-six percent of study participants were found to have autoimmune antibodies when they were admitted to the hospital. Levels of anti-DNA and anti- phosphatidylserine antibodies were then strongly linked to the severity of illness. Specifically, 86 and 93 percent of patients with high levels of anti-DNA and anti- phosphatidylserine antibodies, respectively, experienced severe COVID-19.
Levels of anti-DNA antibodies were also linked to increases in blood coagulation (thrombosis) and cell death (lysis), especially in muscle tissue. Researchers reported both thrombosis, which can lead to life-threatening blood clots, and damage to muscle tissue, especially in the heart, have been observed in the most serious cases of COVID-19.
“Our overall observations suggest that in severe cases of COVID-19, the production of autoimmune antibodies plays a key role in blood clotting and cell death,” says study senior investigator Ana Rodriguez, Ph.D., a professor in the Department of Microbiology at NYU Langone. “Our study adds evidence to the underlying premise of the disease that the misguided immune system’s response is doing more damage than the actual viral infection itself.”
Rodriguez noted that those further studies are necessary to determine if autoimmune antibodies are indeed the “cause or effect” of the blood clotting and cell lysis observed in her team’s study.
If it is discovered to be a cause of cell damage, new COVID-19 treatments could include antibody injections from healthy donors to dilute the presence of autoimmune antibodies. Other therapies may include biodegradable antigens that attach to autoimmune antibodies and neutralize them but do not lead to a lasting antibody immune reaction of their own.