“COVID-19 Infection and Autoimmune Disease: Risks and Possible Mechanisms”

2023-05-26 17:01:41

MONTREAL — Patients who have been infected with the COVID-19 virus appear to be at a higher risk of developing an autoimmune disease, three new studies warn.

Experts don’t fully understand the association that seems to exist between the two, but it’s not entirely new to see an autoimmune disease associated with a previous infection, whether viral or bacterial.

“There are several other autoimmune diseases that have been associated with different types of viruses,” said Dr. Inés Colmegna, who is a rheumatologist and scientist in the RI-MUHC’s Infectious Diseases and Immunity in Global Health Program.

“It is a mechanism that is known and it is one of many mechanisms that might be [présents] in a patient who is predisposed to develop an autoimmune disease.”

Epstein-Barr virus infection, for example, has been associated for many years with autoimmune diseases such as multiple sclerosis and rheumatoid arthritis.

The body usually takes a week or two to produce specific antigens in response to an infection. In the case of a serious infection, such as COVID-19, the body therefore hastens to produce less specific antigens which may attack healthy tissue by mistake. These less specific antigens normally fade when the more specific antigens are ready, but they may persist in some patients and become problematic.

Some patients also seem to have a genetic predisposition to develop an autoimmune disease. In the case of type 1 diabetes, for example, antibodies may circulate in the body for ten years before the appearance of the first clinical symptoms.

In other words, the immune system of these patients seems to predispose them to an autoimmune disease in response to an infection, and it is this infection that turns everything upside down.

“It’s not enough to have been infected with COVID or HIV or hepatitis C,” said Dr. Colmegna. The host must be predisposed [à une maladie auto-immune]. So there is a very small fraction of people who have had COVID who will develop an autoimmune disease.

Even if there were to be an increase in the incidence of rheumatoid arthritis ten years from now, she cites as an example, it would be virtually impossible to associate this increase with the COVID crisis, regardless of all the other factors that may have surfaced during this period.

You have to be very careful before concluding a causal link, underlined Dr. Colmegna. A patient who suddenly experiences pain in the joints should therefore not immediately conclude that he has arthritis following being infected with the COVID virus.

“We must not sow panic in the community, concluded Dr. Colmegna. You have to keep in mind that most of us have had COVID, and you can’t think that everyone who has had COVID will develop an autoimmune disease.

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