Some Covid-19 patients develop antibodies that attack the body

In a still preliminary study, a research team has found that many patients with Covid-19 produce particular antibodies, called auto-antibodies, usually present in autoimmune diseases and directed against the body. Here are what antibodies are and what this element could mean

(photo: Piro4d via Pixabay) By now we know: in Covid-19 the role of the immune system is central and excessive activation can become counterproductive, causing inflammation widespread with very serious consequences. But the immune system is also involved in another hitherto unknown mechanism, at least in this infection. Today, a research group from Emory University in Atlanta, in fact, has found that some patients with Covid-19 and hospitalized in intensive care develop particular antibodies, called autoantibodies, directed against our own organism, similar to those produced in various autoimmune diseases. The study, conducted on a small sample of patients, is not yet peer reviewed but is available in preprint. We still do not know what the role of these autoantibodies is, however their presence could indicate that patients with Covid-19 may benefit from treatments for autoimmune diseases.

Antibodies directed against our tissues

The researchers analyzed the data of 52 Sars-Cov-2 positive people who received assistance in intensive care units and observed that more half of the patients had autoantibodies, having no history of autoimmune diseases. Auto-antibodies are present in the case of autoimmune alterations and diseases, such as connective tissue diseases (including lupus) and some arthritis, including rheumatoid arthritis, and other diseases. According to the authors, the "alarming" presence of these antibodies even in patients with Covid-19 is not a completely unexpected surprise, given that the phenomenon has also been documented in other infectious diseases, such as tuberculosis.

In particular, patients with levels of C-reactive protein (a marker of inflammation) were more prone to this phenomenon and as many as two thirds of them had developed auto-antibodies. The most frequently detected antibodies are anti-nucleus antibodies (Ana) and rheumatoid factor. To detect them, a blood test is enough and these are simple tests, as the authors point out, which can be done in most hospitals.

How autoantibodies behave

The point is that we still do not know how these autoantibodies act with respect to Covid-19 infection, as Matthew Woodruff, first author of the work clearly explains in an article in The Conversation. These autoantibodies could even be beneficial, through some still unknown cellular mechanism, in fighting infection. Or vice versa they could contribute to aggravate the infection. Or, more worryingly, this response could persist and the autoantibodies remain, explains the expert, with the appearance of an alteration or an autoimmune disease. The authors also wonder if the presence of these antibodies can partly explain the frequent aftereffects, even serious ones that have been reported by various patients, from persistent fatigue to lung damage to other disorders, the so-called long Covid.

Refine treatments against Covid-19

Carrying out further studies on these antibodies in patients with Covid-19 is also important for another reason. Their activation could be one of the explanations why many patients treated with dexamethasone, an anti-inflammatory steroid used in various autoimmune diseases, benefit from this therapy. These results, the authors explain, could help identify targeted treatments for patients with Covid-19 and with Ana or other positive autoantibodies, given that with a simple test it is possible to detect the presence of these antibodies and distinguish cases. Even patients with long Covid, if these antibodies are present, could benefit from specific treatments. Finally, the authors conclude, better understanding whether Covid-19 infection is frequently associated with this phenomenon is important to better understand the disease and to act promptly in the case of patients who continue to have autoantibodies.