About half of patients hospitalized with COVID-19 develop dangerous immune system proteins that attack the body’s own tissues, a new study finds.
Researchers at Stanford University studied blood samples from nearly 200 patients hospitalized in the early months of the Covid pandemic and identified signals in the blood of these patients that were similar to those seen in patients with lupus and other autoimmune diseases.
Half of the patients developed so-called autoantibodies
About 20 percent of patients who had multiple blood draws had developed these “rogue antibodies” within the first week in the hospital, the researchers found.
“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,” said one of the study’s senior authors.
Further research is needed to determine links between these autoantibodies and severe Covid symptoms, as well as possible links to long-term Covid.
More than half of patients hospitalized with Covid develop “rogue” attacks that attack their own body tissues, a new study finds. Pictured: A health worker treats a patient in the Covid ICU at Freeman Hospital West in Joplin, Missouri, August 2021
The Covid patients tested positive for a number of autoantibodies linked to various autoimmune diseases
From the start of the pandemic, doctors have noted that patients with severe Covid cases share the same 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 diseases include lupus, celiac disease, and type 1 diabetes.
Autoimmune diseases are often accompanied by swelling, blood clots, fatigue and fever – all symptoms that doctors have observed in Covid patients.
Researchers have also suggested that an autoimmune response could be a cause of long-term Covid, with patients experiencing symptoms for much longer than a typical two-week infection period.
A new study – published on Tuesday in Nature Communications – reveals how common autoimmune reactions occur in critically ill Covid patients.
The study was led by researchers from Stanford University, Philipps University Marburg in 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 in facilities affiliated with Stanford and 48 patients in Kaiser Permanente, another California hospital system.
Studying these blood samples, the researchers looked for autoantibodies, which are types of immune system proteins that attack the body’s own tissues and often cause autoimmune diseases.
Previous research has found autoantibodies in Covid patients and in children with Children’s Multisystem Inflammatory Syndrome (MIS-C).
The Stanford researchers looked for many different antibodies, including those associated with various autoimmune diseases such as lupus and systemic sclerosis.
Compared to healthy controls (HC), the Covid patients were more likely to test positive for autoantibodies common in connective tissue disorders and other conditions
Overall, they found that more than half of Covid patients had at least one type of autoantibody in their blood, compared with less than 15 percent of healthy patients used as controls.
This autoimmune response could be triggered by an intense, long-term Covid infection that sends the immune system into “overdrive,” the researchers said in a press release.
For some patients, a coronavirus infection can lead to higher levels of natural immune system proteins that were present before the virus entered the body.
For others, the immune system can be activated by coronavirus particles that resemble human proteins.
“It’s possible that during a poorly controlled SARS-CoV-2 infection — where the virus lingers for too long while an intensifying immune response continues to break viral particles into bits — the immune system might get bits and pieces of the virus it hadn’t seen before.” , explains Dr. PJ Utz, professor of immunology at Stanford and lead author of the study.
‘If one of these viral pieces is too similar to one of our own proteins, it can 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 the patients had anti-nuclear antibodies, another common autoantibody associated with these conditions.
And in a specific blood test that looked for many different antibodies at the same time, 41 of 51 (80 percent) patients tested positive for at least one autoantibody.
Some of the Covid 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 “rogues” early in their hospital stay.
“Within a week of checking into the hospital, about 20 percent of these patients had developed new antibodies to their own tissues that were not there on the day of admission,” says Utz.
“In many cases, these autoantibody levels were comparable to what you would see in a diagnosed autoimmune disease.”
These findings may indicate that severely ill Covid patients may suffer from autoimmune-like conditions after recovering from their initial infection.
Or, as Utz put it, “If you get sick enough from COVID-19 to end up in the hospital, you might not be out of the woods even after you recover.”
The findings give Americans even more motivation to get vaccinated, Utz said, because vaccination doesn’t trigger the body’s autoimmune response in the same way a Covid infection does.
“If you haven’t been vaccinated and say to yourself, ‘Most people who get COVID will get over it and be fine,’ remember you can’t know ahead of time that when you get COVID-19 it will be a mild case.” be,” Utz said.
“If you get a bad case, you could get yourself in trouble for a lifetime because the virus can disable autoimmunity.”
Utz and fellow scientists plan to continue exploring the links between autoimmunity and severe Covid disease, as well as the links between autoimmunity and long-term Covid.