As if coming down with COVID-19 wasn’t bad enough, a new study has found the disease has a nasty extra trick up its sleeve. According to researchers from Stanford University, COVID-19 patients who end up in the hospital are significantly more likely to have autoantibodies – antibodies that attack their own body – than those who don’t get sick with the virus.
The worst part? These autoantibodies can be early signs of autoimmune disease – meaning COVID-19 can continue to wreak havoc on your body well after you think you’re clear.
“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 Paul Utz, MD, professor of immunology and rheumatology at Stanford Medicine in a statement. He is the co-lead author of a paper on the discovery published last week in the journal Nature Communications.
“Within a week after checking in at the hospital, about 20 percent of [hospitalized COVID-19] patients had developed new antibodies to their own tissues that weren't there the day they were admitted,” he added. “In many cases, these autoantibody levels were similar to what you'd see in a diagnosed autoimmune disease.”
Those were just the patients whose blood samples were available upon admission. When the researchers analyzed the blood of nearly 200 hospitalized COVID-19 patients compared to a healthy control group, they found anti-cytokine antibodies in three-fifths of the COVID-19 patients – four times the levels found in the control group.
Cytokines are proteins that help control the immune system, and they’re normally an extremely important player in the fight against diseases. However, if the body’s defense system is triggered by a long-lasting and hard-hitting infection – for example, a nasty bout of long covid – it can get confused by the overabundance of cytokines, and start attacking them instead of the virus.
“It's possible that, in the course of a poorly controlled SARS-CoV-2 infection – in which the virus hangs around for too long while an intensifying immune response continues to break viral particles into pieces – the immune system sees bits and pieces of the virus that it hadn't previously seen,” explained Utz. “If any of these viral pieces too closely resemble one of our own proteins, this could trigger autoantibody production.”
This isn’t the first time COVID-19 has been associated with the emergence of autoimmune disease. A number of people – only a small number – have reported developing conditions such as multiple sclerosis, lupus, and the rare but serious Guillain-Barré Syndrome after recovering from COVID-19. A lot of the details about this phenomenon are still hazy, however, and the reasons why those patients in particular were affected, the precise mechanism of the illnesses’ development, and in some cases even the autoimmune conditions themselves, are still not fully understood.
Nevertheless, Utz has some sage advice for those who want to avoid a potential autoimmune condition down the line: get vaccinated. Unlike the COVID-19 virus, vaccines – in particular, the Pfizer vaccine – don’t trigger this autoimmune response.
“If you haven't been vaccinated and are telling yourself, 'Most people who get COVID get over it and are OK,' remember that you can't know in advance that when you get COVID-19 it will be a mild case,” cautioned Utz. “If you do get a bad case, you could be setting yourself up for a lifetime of trouble because the virus may trip off autoimmunity.”
“We can't say yet that you'll definitely get an autoimmune disease – we haven't studied any patients long enough to know whether these autoantibodies are still there a year or two later,” he added. “But you certainly might. I wouldn't want to take that chance.”