A pilot study by HIV researchers from Aarhus University and Aarhus University Hospital in Denmark has shown that anti-cancer drug romidepsin can activate HIV out of their state of hiding in CD4 cells.

CD4 cells are white blood cells that fight infection and their count is an indication of how strong or weak a person's immune system is.

HIV remains a chronic, life-long infection due to its ability to stay hidden within infected blood cells. According to researchers, these cellular "reservoirs" contain the genetic code of HIV. They remain invisible to the body's immune defences and are not sensitive to anti-HIV drugs.

Why this finding is significant is that romidespin kicks the virus out of the CD4 cells and into the bloodstream in large amounts, leaving a trace on the outside of the CD4 cells - meaning that the body's immune system, the T cells, can trace and destroy the HIV-infected cells.

The results were presented at a session at the 20th International Aids Conference.

Identifying the hidden virus
The researchers found that romidespin increased the virus production in HIV-infected cells between 2.1 and 3.9 times above normal and that the viral load in the blood increased to measure levels in five out of six patients with HIV infection.

"This meeting will be remembered for this research because it truly identified the hidden virus, something that has never been shown in people before," said Stevan Deeks, professor of medicine in residence at the University of California, San Francisco.

The researchers previously showed that the drug panobinostat can activate hidden HIV in the cells, but they have now shown that it is possible to activate the hidden virus to levels readably detectable in the blood by standard methods that could be made available cheaply to low- and middle-income countries.

Immune system to fight HIV
The results are part of a larger study by the Danish researchers, who are investigating the possibilities of combining activation of HIV and a vaccine to strengthen the ability of the immune system to fight HIV.

However, the researchers warned that this is just one step towards finding a solution to the epidemic.

The next step is to conduct a larger trail where the researchers will combine romidespin activation with a vaccine to strengthen the ability of killer T-cells to fight HIV.