Autoimmune diseases are the result of the immune system mistakenly attacks healthy tissues in the body, instead of defending the body against external pathogens. These processes set the stages for chronic diseases like lupus or arthritis. In some patients with lasting antibodies from Covid infections, there is growing evidence that autoimmune diseases are likely to ensue.
A new study has linked ongoing symptoms of coronavirus to signs of autoimmune disease in long Covid patients.
The latest findings, published in the European Respiratory Journal, found eight out of 10 patients had specific antibodies linked to autoimmune disease in the months following an infection.
The leader of the study, Doctor Manali Mukherjee, from McMaster University, Ontario, Canada, said: “Although long Covid is now recognised by bodies like the World Health Organisation, we still know very little about why it develops or how we can help patients.
“I’m a respiratory researcher with a background in studying the immune system and when I experienced the symptoms of long Covid firsthand, I began to wonder about the role of the immune system in this condition.”
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The study was conducted on a sample of 106 people recruited from three hospitals in Canada, who were diagnosed with COVID-19 between 2020 and 2021.
Participants provided blood samples which were tested for antibodies produced by the immune system that sticks to potentially harmful bacteria and viruses.
These specific antibodies target healthy cells and tissues in the body and are known to contribute to autoimmune diseases.
The patients and two control groups were asked if they suffered shortness of breath, coughing or fatigue three, six or 12 months after recovery.
The results showed that nearly 80 percent of patients had two or more of these antibodies in their blood during this period.
This prevalence fell to 41 percent after a year, however, with most healthy volunteers showing no signs of antibodies in their blood.
Doctor Mukherjee noted: “For the majority of the patients in our study, even if they had autoantibodies soon after their infection, this resolved after 12 months.
“However, in some patients autoantibodies persist, and these patients are more likely to continue suffering with symptoms and to need medical help.
READ MORE: Long Covid: Three conditions likely to affect Covid long haulers
“These results point towards the need to test for signs of autoimmune disease in patients with symptoms of long Covid that last for a year or more.”
Professor Carlsten, who co-led the study, added: “Our data on autoantibodies in those months following Covid infection buttresses that of other groups and provides strong plausibility for the presentation of long Covid as a systemic disease.”
The findings reinforce previous findings from a small 2021 study which found long cover patients had 44 percent higher levels of antinuclear antibodies.
Further research in this area could lead to a better understanding of long Covid and how best to treat the condition.
More than 200 symptoms can follow even mild cases of covid, but what occurs in the bodies of these patients has remained unclear.
One theory to explain the persistent symptoms is that long Covid is an autoimmune disease itself, according to the Autoimmune Institute.
This possibility has been illustrated by the similar characteristics shared between long Covid and other autoimmune diseases.
Another potential trigger of chronic illness could be the Epstein-Barr virus, which is a trigger for lupus in certain people, adds the health body.