Autoantibodies may also be among the causes of long Covid

A study speculates that even an excessive attack by the immune system of coronavirus positives may be the cause of long Covid

(illustration: Getty Images) The symptoms of coronavirus infection can last long after the healing. It is the so-called long Covid, a rather widespread phenomenon: just think that about a third of patients continue to have symptoms even more than six weeks after recovery. And that now, according to a new study from Yale University, it seems to be also associated with the immune system: its excessive response against the virus, in fact, could lead to a more severe form of Covid-19 and, in some cases, leave the patients with symptoms that persist long after the virus has been defeated. Preliminary results, which have yet to be reviewed, show that patients with Covid-19 can develop large numbers of autoantibodies in the blood targeting organs, tissues and the immune system itself, rather than fighting the coronavirus.

To understand this, researchers screened 194 patients and hospital workers with varying severities of Covid-19 and compared their immune responses to those of healthy, uninfected people. From the analyzes, the team found that in the first group there was a huge increase in the reactivity of autoantibodies, particular antibodies similar to those usually found in autoimmune diseases, which accidentally attack the body's proteins, interrupting their function. And, therefore, they block antiviral defenses, eliminate useful immune cells (such as B lymphocytes) and attack the body on several fronts, from the brain, blood vessels and liver to connective tissue and the gastrointestinal tract. More than 5% of hospitalized patients, the researchers explain, had autoantibodies that weakened the immune response of proteins called interferons, and were therefore no longer able to control the amount of virus in the body.

From further tests Furthermore, it was found that the more autoantibodies were present in the blood, the more severe the disease. “Patients with Covid-19 produce autoantibodies that actually interfere with immune responses against the coronavirus,” explains Aaron Ring, one of the authors of the study. "We believe that these autoantibodies are harmful to these patients," continues the expert, noting that the harmful effects could continue even after infection, leaving patients with long-lasting medical problems. "Since antibodies can persist for a long time, it is plausible that they can contribute to the development of long Covid".

We know that diseases such as rheumatoid arthritis, lupus and multiple sclerosis are driven by a malfunction of the immune system, but it is not yet clear how viral infections can induce autoimmune reactions. In fact, studies are currently underway to understand whether autoantibodies are responsible for the long-term symptoms of other diseases, such as Ebola and Chikungunya. "Post-Covid syndromes could most likely be caused by long-lasting autoantibodies that persist even after the virus is cleared," Ring explains. "If that were really the case, there are immunosuppressive treatments, such as those used for rheumatological diseases, which could also be effective for the coronavirus."