Autoimmune disease risk for long COVID patients
Thursday September 22nd 2022
People with long COVID who suffer from fatigue and shortness of breath after a year show signs of autoimmune disease, a new Canadian study has found.
Researchers say this finding, published in the *European Respiratory Journal*, provides important clues about long COVID that could lead to improvements in diagnosing and treating the condition.
Study author co-leader Manali Mukherjee from McMaster University, Ontario, said: “Although long COVID is now recognised by bodies like the World Health Organization, 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 first-hand, I began to wonder about the role of the immune system in this condition.”
Dr Mukherjee, co-study lead Professor Chris Carlsten at the University of British Columbia, Vancouver, and colleagues recruited 106 people with COVID-19 between August 2020 and September 2021 and who were under the care of three hospitals - St. Joseph’s Healthcare Hamilton, Vancouver General Hospital and St. Paul’s Hospital, Vancouver.
Also included in the study were 22 healthy volunteers and 34 people who had experienced a non-COVID respiratory infection.
The COVID patients were asked three, six and 12 months after they recovered from the infection if they were suffering any shortness of breath, coughing or fatigue, which are typical long COVID symptoms.
Out of the 106, 98 were still taking part in the study after six months, while 57 responded after 12 months. Researchers say this may be due to patients recovering.
Participants also gave blood samples, which were tested for particular antibodies. Nearly 80% of the COVID-19 patients had two or more of these antibodies in their blood three months and six months after the infection.
After a year, it fell to 41%. Most of the healthy volunteers had no sign of these antibodies in their blood and in those who had experienced a non-COVID respiratory infection, levels of these antibodies were comparatively low.
Researchers also found U1snRNP and SSb-La autoantibodies plus cytokines that cause inflammation in about 30% COVID patients a year after infection. These were found mainly in patients who continued to suffer fatigue and shortness of breath.
Dr Mukherjee said: “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.
“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 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.”
Dr Mukherjee and her colleagues will now study long COVID patients over a period of two years to see how their levels of autoantibodies change.
Son K, Jamil R, Chowdhury A, et al. Circulating anti-nuclear autoantibodies in COVID-19 survivors predict long-COVID symptoms. *European Respiratory Journal 2022* 21 September 2022
Tags: Flu & Viruses | North America
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