There has been a lot of excitement in the press recently about a new gene editing technology , called CRISPR-Cas9. The aim of this technology is to edit the genes made by immune cells to make them resistant to HIV. The technique has been successfully used in other diseases and so has increased hopes that it could also be used to combat HIV. However in a recent study published in Cell Reports has cast a shadow of doubt on the early claims of an HIV cure.

When HIV infects a T – cell ( the immune cells that help attack viruses) , it inserts part of its genome into the DNA of the T cell and then hijacks the cell to produce more copies of HIV. The idea was that if that cell is equipped with Cas-9 it would be able to to cut out this part and therefore stop HIV from producing more copies.

A team led by Virologist Chem Liang at McGill University in Montreal Canada , seemed to have succeeded in doing just that. Initially the procedure seemed to work, however within 2 weeks the altered cells started producing copies of HIV again. It turns out that HIV had again, cleverly developed mutations that rendered the CRISPR -Cas9 enzyme ineffective.

This didn’t come as a complete surprise as we know that HIV is very good at mutating and escaping any attempts to thwart it. However what surprised the team was the speed at which HIV managed to mutate and become resistant to the gene editing tool.

The good news is that they do not think the problem is insurmountable. The theorise that the technique could still work if given at the same time as antiretroviral drugs or by attacking several HIV genes at once.

Many questions remain to be answered to see if CRISPR-Cas9  technology has a future role in an HIV cure, but every day we learn a bit more about HIV and also about ways that we can potentially overcome and defeat this virus. Only time will tell.