The first phase 2 gene therapy trial for treating HIV has shown some promising first results. The research was the work of Dr Ronald T Mitsuyasu of the University of California Los Angeles (UCLA) and colleagues from UCLA and other research centers in the US, Australia and Germany, and was published online in Nature Medicine on 15 February.

Data from an advanced phase of the test process confirms that the quest to use transplanted genes to roll back the human immunodeficiency virus (HIV) is valid, they said. The virus was blocked from replicating itself by injecting sufferers with blood stem cells carrying a molecule which targeted two HIV proteins.

Half the group was given blood stemcells that had been infiltrated by a crippled virus containing a key gene, while the other was given a harmless lookalike substance. The gene encodes something called an RNA enzyme, or ribozyme for short -- a small molecule that, like a spanner thrown into a machine, is intended to block HIV from replicating once it infects a cell.

After 48 weeks the researchers found there was no statistically significant difference in the amount of HIV circulating in the blood of the two groups of patients. However, after 100 weeks the patients who received the gene therapy had higher levels of CD4+ cells - the key cells of the immune system which are specifically destroyed by HIV.

“It provides proof of concept and early indications are that, with more refinement, this approach may be a viable one for controlling HIV directly in people without the need for continuous HIV medication,” said Mitsuyasu.

Leading to acquired immunodeficiency syndrome, or AIDS, the virus is one of the most deadly and prolific viruses in human history. Since it was discovered in 1981, about 450,000 Americans lost their lives to HIV/AIDS.