CCR5 is the co-receptor that most strains of HIV use to enter cells. People with two copies of a naturally occurring genetic mutation called CCR5-delta-32 do not produce this co-receptor and are resistant to HIV infection. A man known as the Berlin patient appears to be free of HIV, seven years after receiving transplanted bone marrow stem cells (which give rise to all blood cells) from a donor with this mutation.

In clinical trials, samples of CD4 T-cells are collected from HIV-positive participants, genetically modified in a laboratory and allowed to multiply. The modified cells, called SB-728-T, are then re-infused back into the same participant. The idea is that these modified cells – being protected against HIV entry – will persist while normal T-cells are killed off by the virus. In summary, this study showed that modified SB-728-T cells persist and appear to have a selective advantage over unmodified cells when exposed to HIV during ART interruption. This may prove to be a useful tool for developing a functional cure, though it is early days yet.

The full article can be read here.