Occurrence of Autoimmune Diseases following COVID-19
January 10, 2023
Several studies have reported the co-occurrence of autoimmune diseases (such as systemic lupus erythematosus, Guillain-Barre syndrome, autoimmune thyroid disease, and immune thrombocytopenic purpura) following COVID-19. The time between COVID-19 symptoms and the autoimmune disease symptoms in those reports ranges between 2 and 33 days.
Scientists identified several components and mechanisms of the immune system that can be involved in the connection between COVID-19 and autoimmune diseases; this includes SARS-CoV-2 hyperactivation of the immune system and molecular mimicry. Molecular mimicry occurs when there is a resemblance between foreign proteins, in this case, COVID-19 proteins, and the proteins in the human body. In such cases, the antibodies created against the viral proteins can turn against human proteins. Researchers found COVID-19 and human proteins that share similar parts. Those proteins can be candidates for molecular mimicry.
Understanding the immune system response to SARS-CoV-2 can help design better therapies targeting specific components of the overreacting immune system. COVID-19 and autoimmune disease share some similarities regarding molecular mechanisms of diseases. The authors of a paper published in November 2022 suggest that drugs used to treat autoimmune patients can serve as a potential treatment for COVID-19 patients. Some reports show that drugs used to treat autoimmune diseases can be effective in COVID-19 patients. However, some may be harmful as well. Generally, in the initial COVID-19 phase, the immune response is needed to stop the virus from replicating. In this phase, immunosuppressive drugs can be harmful. However, when the patient experiences hyperactivation of the immune system, in later phases, immunosuppressive drugs can be beneficial as they can suppress the hyper-activated immune system.
There is still much to be understood about the connection between COVID-19 and autoimmune diseases. Since most of the studies on autoimmune disease occurrence following COVID-19 report on a single or a few patients, there is a need for systemic research regarding the frequency of autoimmune diseases following COVID-19.