The gene that protected some against the Black Death can help and harm people today

By Cara Murez

health day reporter

WEDNESDAY, March 8, 2023 (HealthDay News) — Some people may have a gene that helps protect them from respiratory diseases like COVID-19 — and helped their ancestors fight off the plague.

It has a cost.

This same genetic variation could be linked to an increased risk of autoimmune diseases, including rheumatoid arthritis and inflammatory bowel disease, according to British researchers.

“This gene basically chops up proteins for the immune system,” said lead author Fergus Hamilton, a researcher at the University of Bristol.

“Although we don’t know the exact mechanism influencing disease risk, carriers of alleles that provide more protection against respiratory disease appear to have an increased risk of autoimmune disease,” he said in a statement. university press release. “This is potentially a great example of a phenomenon called ‘balancing selection’ – where the same allele has a different effect on different diseases.”

Previous research has shown that survivors of the bubonic plague pandemic in the Middle Ages, known as the Black Death, carried a variant – or allele – in a gene called ERAP2. Those who died lacked this variant.

The new study found that humans now have the same variants, which is associated with protection against infections such as pneumonia and COVID.

To study this, the researchers looked at infection, autoimmune disease and parental longevity among participants in three large genetic studies.

They looked for links between variation in the ERAP2 gene and the risk of autoimmune disease and infection.

“It’s a theoretical story of balance — tied to historical and contemporary disease patterns — that reflects our past and is rarely seen in real human examples,” said co-author Nicholas Timpson, professor of genetic epidemiology at the university’s MRC Integrative. Epidemiology Unit.

Identifying links between genetics and disease susceptibility may pave the way for potential treatments, the researchers noted. It also highlights potential challenges, they said.

As scientists develop therapies to target ERAP2 for people with Crohn’s disease and cancer, it’s important to consider the potential effects on infection risk posed by these agents, the authors said.

The results of the study were published on March 7 in the American Journal of Human Genetics. Researchers from the universities of Edinburgh, Oxford, Cardiff and Imperial College London also worked on the study.

More information

The US National Library of Medicine has more on genetic variants.

SOURCE: University of Bristol, press release, March 7, 2023

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