You might think a person鈥檚 risk of catching HIV is solely governed by behavioural choices, such as using condoms, and whether someone is exposed to the virus. But genetics also play a role and may account for up to 42 per cent of the variation in people鈥檚 likelihood of acquiring this infection.
The genes involved seem to work at least in part by affecting our immune system. These findings could help us develop new treatments or vaccines against HIV, says Timothy Powell at King鈥檚 College London.
Powell鈥檚 team were interested in the fact that millions of people are exposed to HIV every year but don鈥檛 catch it. For instance, only about a third of babies develop the infection after being born to HIV-positive mothers who aren鈥檛 taking drug treatment for the virus.
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In 2013, another team looked at the DNA of about 6000 people with HIV and 7000 similar people without the virus to see if there were any relevant genetic variations between the two groups.
This team identified only one gene, which encodes a protein we already knew about, called CCR5. This is present on the surface of immune cells and HIV attaches to it in order to enter these cells.聽A small percentage of Caucasian people lack this protein and seem to be virtually immune to catching HIV.
Now Powell鈥檚 team have reanalysed the data from this 2013 study using more powerful statistical techniques, and have found there are many other genetic variants that play a role.
When the team then looked at data from a separate large study of people鈥檚 health and genes, they found that high genetic risk of infection with HIV was linked to having lower blood levels of a molecule called CCL17, which is involved in signalling between immune cells.
If the findings are confirmed, this suggests that vaccine developers could focus on people with low CCL17 when developing their products, says Powell.
Scientific Reports
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