Some long COVID patients suffering symptoms including fatigue and shortness of breath are showing signs of autoimmune diseases like rheumatoid arthritis and lupus, suggests a Canadian study that builds on similar findings elsewhere.
Manali Mukherjee, who led the study and is a respiratory researcher at McMaster University in Hamilton, said two specific abnormal antibodies, or autoantibodies, which attack healthy tissues and are known to cause autoimmune disease, persisted in about 30 per cent of patients a year after they became infected.
The research was based on blood samples from patients who were diagnosed with COVID-19 between August 2020 and September 2021 and received care at two hospitals in Vancouver and another in Hamilton.
The persistence of autoantibodies for a year or longer points to the need for patients to see a specialist who could test for signs of autoimmune disease, she said of conditions that also include Type 1 diabetes and multiple sclerosis.
"If you are having long COVID symptoms, even 12 months after getting COVID, please consider getting a rheumatological checkup, just to make sure that there is no trajectory towards systemic disease," Mukherjee said.
The study, which also involved Dr. Chris Carlsten, from the University of British Columbia's division of respiratory medicine, was published Thursday in the European Respiratory Journal and involved 106 patients.
The work supports emerging research on long COVID, which mostly affects women, Mukherjee said.
A study of 300 patients published earlier this year in the journal Cell by researchers in the United States was the first to show that autoantibodies among those infected with the virus can lead to long COVID symptoms, but it was limited to three to four months after recovery, Mukherjee said.
A Swiss study of 90 patients published last April in the journal Allergy suggested autoantibodies can be present a year following infection in 40 per cent of patients.