Autoimmune disorders cause the body’s own defense system to attack normal, healthy cells. They can also leave people vulnerable to diseases—resulting in more severe and deadly infections. But they may not be all bad news—new research suggests that one autoimmune disease might actually provide protection against COVID-19.
In a paper published November 3 in the journal PLOS Genetics, researchers from King’s College London discovered that a gene linked to lupus, or systemic lupus erythematosus (SLE), might protect against severe COVID-19 infections. The gene, dubbed TYK2, increases your risk of developing lupus. However, the study’s authors also found that it protects against viral infections like COVID-19.
At the heart of this process are interferons: proteins in the body’s immune system that send signals to other cells to fight viruses. “TYK2 is involved in interferon production, a process that is important in response to viral infection and known to be dysregulated in SLE patients,” the study’s authors told The Daily Beast in a joint statement.
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Changes or mutations to the TYK2 gene can increase interferon production, resulting in increased protections against viral infections. Put it another way: A lower amount of interferons “makes it easy for viruses to infect us, while too much can lead to an overactive immune system” resulting in diseases like SLE, the study’s authors explained. “[Having] elevated levels of interferon increases the risk of autoimmune disease as it can stimulate the immune system to attack healthy cells.”
Part of the reason this might happen is due to natural selection. Over time, the human body got stronger and better able to fight off viruses. However, this occasionally creates a mutation that results in our body being too good at fighting things off—including itself.
The researchers caution that this doesn’t necessarily mean that those with lupus are necessarily better at fighting COVID-19 than those without lupus. For one, there are many factors that cause lupus ranging from environmental to genetic, according to the authors. It wouldn’t be right to use a single gene to predict either SLE or severe infections to COVID-19.
But they do say that there are many genes linked to both lupus and the coronavirus. This might suggest that that there’s a give and take with the human genome. While it can help you against viruses, it might result in factors for autoimmune disease.
The study’s authors hope that future studies building off of this one will take a look at a broader and more diverse sample of people, as this one contained primarily people of European descent. They also hope to compare it with larger population studies since lupus is also determined by environmental factors.
Overall, this research helps provide a better understanding of how exactly the immune system helps protect against pathogens like the coronavirus—though it might cause a whole host of other issues as well.
