According to a new study, approximately half of patients hospitalized with COVID-19 develop dangerous immune system proteins that attack the body’s own tissues.
Researchers at Stanford University studied blood samples from nearly 200 patients hospitalized with Covid during the early months of the pandemic and identified signs in the blood of these patients that were similar to those of patients with lupus and other autoimmune conditions.
Half of the patients developed what are known as autoantibodies
The researchers found that about 20% of patients who had blood drawn several times had developed these “rogue antibodies” during the first week in hospital.
“If you get sick of COVID-19 enough to end up in the hospital, you may not be out of the woods even after you recover,” said one of the study’s lead authors.
Further study is needed to determine the links between these autoantibodies and the severe symptoms of Covid, as well as the possible links with long Covid.
According to a new study, more than half of patients hospitalized with Covid develop “rogue antibodies” that attack their own body tissue. Pictured: A healthcare worker cares for a patient in the Covid ICU at Freeman Hospital West in Joplin, Missouri, August 2021
Covid patients tested positive for various autoantibodies associated with different autoimmune conditions
Since the onset of the pandemic, doctors have noticed that patients with severe cases of Covid share common symptoms with autoimmune diseases.
In autoimmune diseases, a person’s immune system mistakenly attacks other parts of the body instead of attacking a foreign virus or other type of invader.
These autoimmune conditions include lupus, celiac disease, and type 1 diabetes.
Autoimmune conditions usually involve swelling, blood clots, fatigue, and fever, all symptoms that doctors have observed in patients with covid.
Researchers have also suggested that an autoimmune reaction may be a causative factor for long-term covid, in which patients experience symptoms for much longer than a typical two-week infection period.
A new study, published Tuesday in Nature Communications, reveals the degree of frequency of autoimmune reactions in critically ill patients with Covid.
The study was led by researchers from Stanford University, Philipps University in Marburg, Germany, and the University of Pennsylvania.
The researchers studied blood samples from patients hospitalized with Covid in March and April 2020.
This included 147 patients at Stanford-affiliated facilities and 48 patients at Kaiser Permanente, another California hospital system.
In studying these blood samples, the researchers looked for autoantibodies, which are types of immune system proteins that attack the body’s own tissues, which often cause autoimmune conditions.
Previous research has found autoantibodies in Covid patients and in children with multisystem inflammatory syndrome in children (MIS-C).
Stanford researchers looked for many different antibodies, including those associated with different autoimmune diseases such as lupus and systemic sclerosis.
Compared with healthy controls (HC), patients with Covid were more likely to test positive for autoantibodies that are common in connective tissue disease and other conditions.
Overall, they found that more than half of the patients with Covid had at least one type of autoantibody in their blood compared to less than 15% of the healthy patients who were used as controls.
This autoimmune reaction can be caused by an intense, long-term Covid infection that sends the immune system into “excessive driving,” the researchers said in a press release.
For some patients, a coronavirus infection can cause higher levels of natural immune system proteins that were present before the virus entered the body.
For others, the immune system can be triggered by coronavirus particles that look like human proteins.
“It is possible that in the course of a poorly controlled SARS-CoV-2 infection, in which the virus stays too long while an intensifying immune response continues to break up viral particles into pieces, the immune system sees pieces of the virus that do not had seen it before, ”explained Dr. PJ Utz, a Stanford professor of immunology and lead author of the study.
“If any of these viral pieces look too much like one of our own proteins, this could trigger the production of autoantibodies.”
About 60 percent of patients had anti-cytokine antibodies, which attack proteins involved in cell signaling and are common in autoimmune diseases.
A quarter of patients had anti-nuclear antibodies, another common autoantibody associated with these conditions.
And, in a specific blood test that looked for numerous antibodies at once, 41 of 51 patients (80 percent) tested positive for at least one autoantibody.
Some of Covid’s patients tested positive for two or more autoantibodies
A small number of patients tested positive for two or more autoantibodies, and some even tested positive for these dangerous ‘rogue antibodies’ in the first hospital stays.
“Within a week of being hospitalized, about 20 percent of these patients had developed new antibodies against their own tissues that were not there the day they were admitted,” Utz said. .
“In many cases, these autoantibody levels were similar to what you would see in a diagnosed autoimmune disease.”
These findings may suggest that patients with severely ill Covid may experience autoimmune conditions after recovering from the initial infection.
Or, as Utz said, “If you get sick enough from COVID-19 to end up in the hospital, you may not be out of the woods even after you recover.”
The findings give Americans additional motivation to get vaccinated, Utz said, because vaccination does not trigger the body’s autoimmune response in the same way as a Covid infection.
“If you haven’t been vaccinated and you say,‘ Most people who get COVID outperform it and are fine, ’remember you can’t know in advance that when you get COVID-19 it will be a mild case,” Utz said.
“If you have a bad case, you could be preparing for life-long problems, as the virus can cause autoimmunity.”
Utz and other scientists plan to continue investigating the links between autoimmunity and severe Covid disease, as well as the links between autoimmunity and long Covid.
