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HIV Therapeutics– Gene Editing Shows Promise in Clinic

From Nature News

The Stem Cell Portal has recently reported on new studies which demonstrate a potential cure for HIV/AIDs based around the CCR5 receptor (Stem Cell Cures for HIV?). It is known that HIV can infect CD4+ T cells through the CCR5 cell surface receptor and the subsequent destruction of the immune system is driven by this loss of normal CD4+ T cells. It has been discovered that a homozygous deletion in the CCR5 allele entails a resistance to HIV infection, while heterozygous patients show slower disease progression. Now Nature News reports on results from a phase I safety trial presented at the Conference on Retroviruses and Opportunistic Infections by Sangamo BioSciences of a zinc finger nuclease (ZFN) which targets and artificially disrupts the CCR5 gene.

The trial involved the isolation of CD4+ cells from male patients with HIV that were being treated with conventional anti-retroviral therapies, the treatment of patient-derived CD4+ cells with a ZFN targeting CCR5 followed by their subsequent re-infusion. Encouragingly, this led to a boost in the numbers of immune cells in 5 out of 6 patients with no serious side effects. Not only were the engineered cells shown to migrate throughout the body, but importantly, colonise the gut mucosa - a significant reservoir for HIV. The efficiency, however, is reported to be relatively low, the treatment may have off-target effects and it is also not yet clear whether the increase in the patient’s immune cell number was due to CCR5disruption or because the extracted cells were activated during the in vitro culture, meaning that additional studies with appropriate controls must be ensued.

Nevertheless, this does suggest that we may be on our way to finding an effective treatment for this currently incurable disease which affects tens of millions of people worldwide.

Read the entire report at Nature News.



Targeted gene editing enters clinic
Heidi Ledford
Published online 1 March 2011 | Nature 471, 16 (2011) | doi:10.1038/471016a