The gene variant, which is surprisingly common in people living today, reduces the risk of HIV infection by 27 percent, according to a statement published in the specialist magazine “PNAS” on Monday study.
Gene variant beneficial in the past
In addition to risk factors such as advanced age and chronic diseases, genetic heritage can also increase or decrease the individual risk of severe coronavirus disease. In 2020 showed Hugo Zeberg from the Karolinska Institutet in Stockholm from the Max Planck Institute for Evolutionary Anthropology in Leipzig and Svante Pääbo, also from the Max Planck Institute in Leipzig, that an important genetic risk factor for a severe course of Covid-19 is part of the human Neanderthal heritage.
Last year, the research duo examined the same gene variant in the genome of prehistoric humans and found that it has been occurring significantly more frequently since the end of the last ice age. It stands to reason, therefore, that for the most part it has been beneficial to its bearers in the past.
27 percent reduced risk of HIV infection
The Neanderthal variant is located in a region on chromosome three that also contains several genes associated with receptors in the immune system. The HIV virus uses one of these receptors – CCR5 – to infect white blood cells. Zeberg found that people with an inherited risk variant for Covid-19 have fewer CCR5 receptors. The analysis of patient data from three large biobanks showed that carriers of the Covid-19 risk variant have a 27 percent lower risk of HIV infection.
“Having this gene variant can be both good and bad for the carrier: bad if they contract Covid-19, good if they are at risk of HIV infection and have some protection once morest this virus,” explained the Max Planck expert.
Previously probably protection once morest other diseases
However, since HIV only emerged in the 20th century, the protective effect once morest this infectious disease cannot explain why the Covid-19 risk variant was already so widespread in humans 10,000 years ago. The researchers suspect that protection once morest another disease may have contributed to the widespread spread of this particular gene variant following the last ice age.