Blood samples from patients with long COVID who are still suffering from fatigue and shortness of breath after a year show signs of autoimmune disease, according to a study published today (Thursday) in the European Respiratory Journal [1].
Autoimmune disease occurs when the immune system mistakenly attacks healthy parts of the body, instead of defending the body against disease. It causes conditions such as rheumatoid arthritis and lupus.
Researchers say this finding offers clues about the nature of long COVID that could ultimately lead to improvements in diagnosing and treating the condition.
The research was led by Dr Manali Mukherjee from McMaster University, Ontario, Canada and Professor Chris Carlsten at the University of British Columbia, Vancouver, Canada. Dr Mukherjee 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.”
To find out more, 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). Researchers also included a group of 22 healthy volunteers and a group of 34 people who had experienced a non-COVID respiratory infection as a comparison.
On three occasions – three, six and 12 months after they recovered from the infection – patients 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 six months (98 out of 106) while only 57 came back after 12 months. Researchers say this may be due to patients recovering.
Participants also gave blood samples. Researchers tested the samples for 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 researchers looked for antibodies that target healthy cells and tissues in the body and that are known to contribute to autoimmune diseases.
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. 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 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.
Dr Mukherjee explains: “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.
“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 in the longer term.
Dr Eva Polverino from Vall d’Hebron University Hospital, Barcelona, Spain, is Head of the European Respiratory Society’s Respiratory Infections Assembly and was not involved in the research. She said: “Millions of people around the world are suffering with long COVID and that is having an enormous socioeconomic impact. However, there is a lack of evidence on why some people develop the condition and how we can help patients recover.
“We know that certain infections can, in some cases, trigger longer-term autoimmune diseases such as rheumatoid arthritis. This study adds to growing evidence that similar processes may be involved in long COVID. Further work in this area could increase our understanding of long COVID and how best to diagnose and treat the condition.”
News
New Once-a-Week Shot Promises Life-Changing Relief for Parkinson’s Patients
A once-a-week shot from Australian scientists could spare people with Parkinson’s the grind of taking pills several times a day. The tiny, biodegradable gel sits under the skin and releases steady doses of two [...]
Weekly injectable drug offers hope for Parkinson’s patients
A new weekly injectable drug could transform the lives of more than eight million people living with Parkinson's disease, potentially replacing the need for multiple daily tablets. Scientists from the University of South Australia [...]
Most Plastic in the Ocean Is Invisible—And Deadly
Nanoplastics—particles smaller than a human hair—can pass through cell walls and enter the food web. New research suggest 27 million metric tons of nanoplastics are spread across just the top layer of the North [...]
Repurposed drugs could calm the immune system’s response to nanomedicine
An international study led by researchers at the University of Colorado Anschutz Medical Campus has identified a promising strategy to enhance the safety of nanomedicines, advanced therapies often used in cancer and vaccine treatments, [...]
Nano-Enhanced Hydrogel Strategies for Cartilage Repair
A recent article in Engineering describes the development of a protein-based nanocomposite hydrogel designed to deliver two therapeutic agents—dexamethasone (Dex) and kartogenin (KGN)—to support cartilage repair. The hydrogel is engineered to modulate immune responses and promote [...]
New Cancer Drug Blocks Tumors Without Debilitating Side Effects
A new drug targets RAS-PI3Kα pathways without harmful side effects. It was developed using high-performance computing and AI. A new cancer drug candidate, developed through a collaboration between Lawrence Livermore National Laboratory (LLNL), BridgeBio Oncology [...]
Scientists Are Pretty Close to Replicating the First Thing That Ever Lived
For 400 million years, a leading hypothesis claims, Earth was an “RNA World,” meaning that life must’ve first replicated from RNA before the arrival of proteins and DNA. Unfortunately, scientists have failed to find [...]
Why ‘Peniaphobia’ Is Exploding Among Young People (And Why We Should Be Concerned)
An insidious illness is taking hold among a growing proportion of young people. Little known to the general public, peniaphobia—the fear of becoming poor—is gaining ground among teens and young adults. Discover the causes [...]
Team finds flawed data in recent study relevant to coronavirus antiviral development
The COVID pandemic illustrated how urgently we need antiviral medications capable of treating coronavirus infections. To aid this effort, researchers quickly homed in on part of SARS-CoV-2's molecular structure known as the NiRAN domain—an [...]
Drug-Coated Neural Implants Reduce Immune Rejection
Summary: A new study shows that coating neural prosthetic implants with the anti-inflammatory drug dexamethasone helps reduce the body’s immune response and scar tissue formation. This strategy enhances the long-term performance and stability of electrodes [...]
Scientists discover cancer-fighting bacteria that ‘soak up’ forever chemicals in the body
A family of healthy bacteria may help 'soak up' toxic forever chemicals in the body, warding off their cancerous effects. Forever chemicals, also known as PFAS (per- and polyfluoroalkyl substances), are toxic chemicals that [...]
Johns Hopkins Researchers Uncover a New Way To Kill Cancer Cells
A new study reveals that blocking ribosomal RNA production rewires cancer cell behavior and could help treat genetically unstable tumors. Researchers at the Johns Hopkins Kimmel Cancer Center and the Department of Radiation Oncology and Molecular [...]
AI matches doctors in mapping lung tumors for radiation therapy
In radiation therapy, precision can save lives. Oncologists must carefully map the size and location of a tumor before delivering high-dose radiation to destroy cancer cells while sparing healthy tissue. But this process, called [...]
Scientists Finally “See” Key Protein That Controls Inflammation
Researchers used advanced microscopy to uncover important protein structures. For the first time, two important protein structures in the human body are being visualized, thanks in part to cutting-edge technology at the University of [...]
AI tool detects 9 types of dementia from a single brain scan
Mayo Clinic researchers have developed a new artificial intelligence (AI) tool that helps clinicians identify brain activity patterns linked to nine types of dementia, including Alzheimer's disease, using a single, widely available scan—a transformative [...]
Is plastic packaging putting more than just food on your plate?
New research reveals that common food packaging and utensils can shed microscopic plastics into our food, prompting urgent calls for stricter testing and updated regulations to protect public health. Beyond microplastics: The analysis intentionally [...]
