Canadian Study Shows Even After A Year, Up To 41 Percent Of Post-COVID Individuals Still Have Autoantibodies That Causes Autoimmune Issues!
A new study by researchers from McMaster University-Canada and the University of British Columbia-Canada along with medical scientist from the Research Institute of St. Joes, St. Joseph's Healthcare Hamilton-Canada has found that even after a year, up to 41 percent of Post-COVID individuals still have autoantibodies that causes autoimmune issues!
At 3 and 6 months, nearly 80% of the COVID-19 survivors had at least two antibodies that target healthy cells and tissues and contribute to autoimmune diseases, falling to 41% after 1 year.
About 21% to 30% of Post COVID-19 individuals who still had shortness of breath and fatigue was found to have specific antibodies (called anti-U1-snRNP and anti-SS-B/La autoantibodies) and proteins that cause inflammation (TNFα cytokines) at 1 year.
Autoimmune disease occurs when the immune system mistakenly attacks healthy parts of the body instead of defending it against disease. It causes conditions such as rheumatoid arthritis and lupus.
Thailand Medical News
had already previously covered various studies that show SARS-CoV-2 infections triggers the generation of various antibodies that can cause a variety of autoimmune issues! Many of these autoimmune issues also contribute symptoms and conditions manifested in Long COVID.
To date, autoimmunity has not only been reported in patients with severe COVID-19 but also in asymptomatic and mild symptomatic Post COVID individuals.
The Canadian study team investigated whether antinuclear/extractable-nuclear antibodies (ANAs) were present up to a year after infection, and if they were associated with the development of clinically relevant Post-Acute Sequalae of COVID-19 (PASC) symptoms or what is commonly known as Long COVID.
The study team utilized a rapid assessment line immunoassay to measure circulating levels of ANA/ENAs in 106 convalescent COVID-19 patients with varying acute phase severities at 3, 6, and 12 months post-recovery. Patient-reported fatigue, cough, and dyspnea were recorded at each timepoint.
Multivariable logistic regression model and receiver-operating curves (ROC) were used to test the association of autoantibodies with patient-reported outcomes and pro-inflammatory cytokines.
The study findings showed that compared to age- and sex-matched healthy controls (n=22) and those who had other respiratory infections (n=34), patients with COVID-19 had higher detectable ANAs at 3 months post-recovery (p<0.001).
The mean number of ANA autoreactivities per individual decreased from 3 to 12 months (3.99 to 1.55) with persistent positive titers associated with fatigue, dyspnea, and cough severity.
Interestingly, antibodies to U1-snRNP and anti-SS-B/La were both positively associated with persistent symptoms of fatigue (p<0.028, AUC=0.86) and dyspnea (p<0.003, AUC=0.81). Pro-inflammatory cytokines such as tumour necrosis factor alpha (TNFα) and C-reactive protein predicted the elevated ANAs at 12 months. TNFα, D-dimer, and IL-1β had the strongest association with symptoms at 12 months. Regression analysis showed TNFα predicted fatigue (β=4.65, p=0.004) and general symptomaticity (β=2.40, p=0.03) at 12 months.
The study findings showed persistently positive ANAs at 12 months post-COVID are associated with persisting symptoms and inflammation (TNFα) in a subset of COVID-19 survivors.
The research team stressed that the study finding indicates the need for further investigation into the role of autoimmunity in PASC.
The study findings were published in the peer reviewed European Respiratory Journal.
The study team said that this research findings offers clues about the nature of long COVID that could ultimately lead to improvements in diagnosing and treating the condition.
The study was led by Dr Manali Mukherjee from McMaster University, Ontario, Canada and Professor Dr Chris Carlsten at the University of British Columbia, Vancouver, Canada.
Dr Mukherjee told Thailand Medical News
, "Though PASC or long COVID is now recognized 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 firsthand, I began to wonder about the role of the immune system in this condition."
In order to investigate further, Dr Mukherjee and her colleagues recruited 106 people who had been diagnosed with COVID-19 between August 2020 and September 2021 and were under the care of three hospitals in Canada (St. Joseph's Healthcare Hamilton, Vancouver General Hospital and St. Paul's Hospital, Vancouver).
The study team also included a group of 22 healthy volunteers and a group of 34 individuals who had experienced a non-COVID respiratory infection as a comparison.
At time intervals of 3, 6 and 12 months after they recovered from the infections, the participants were asked if they were suffering any shortness of breath, coughing or fatigue (typical symptoms of long COVID).
Most patients were still taking part in the study after 6 months (98 out of 106) while only 57 came back after 12 months. The study team said that this may be due to patients recovering.
All study participants also gave blood samples which were tested particular antibodies. Antibodies are normally produced by the immune system to stick to potentially harmful bacteria or viruses, marking them out for attack by other parts of the immune system. In this case, the study team looked for antibodies that target healthy cells and tissues in the body and that are known to contribute to autoimmune diseases.
Shockingly, 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. This fell to 41% after a year.
However, 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.
The study team also found that two specific "autoantibodies" (called U1snRNP and SSb-La autoantibodies), along with other proteins (called cytokines) that cause inflammation, persisted in around 30% of COVID patients a year after infection. This tended to be among those patients who were also still suffering with fatigue and shortness of breath.
The study team explained, "For the majority 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.”
Thee added, "The study findings 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."
Dr Carlsten added, "The study 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 study team will now study long COVID patients over a period of two years to see how their levels of autoantibodies change in the longer term.
It should be noted that Long COVD is not becoming a major health issue and is expected to become a major burden on public healthcare in coming months and years as it is believed that already more than 3 billion people around the world has already been exposed to the SARS-CoV-2 virus with a large proportion of them manifesting Long COVID conditions.
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