Based on these findings, gene editing technologies, such as zinc-finger nucleases (ZFN) [21], transcription activator-like effector nucleases (TALEN) [22], and more recently, CRISPR-Cas [23], have been developed to edit ex vivo the CCR5 gene, and make the cells resistant to infection, an approach that has also been tested in clinical trials, giving promising preliminary results regarding the safety profile. Here, CCR5 is linked to infection.