HIV scientists have revealed that a cancer-fighting drug has been used to “kick out” hidden HIV and into the bloodstream, exposing them to an attack from the human immune system.
Speaking at the 20th International AIDS Conference in Melbourne, Danish researcher Ole Søgaard, of Aahus University, revealed that a study of six HIV-positive people using anti-cancer medication romidepsin have shown that HIV hidden in resevoirs in the body gets pushed out into the bloodstream, essentially activating and exposing HIV to the immune system.
HIV hibernates in CD4 cells, which is part of the immune system, but these CD4 cells can’t combat HIV, as that is job of the immune system’s killer T-cells.
However, T-cells are unable to detect and fight HIV hidden in CD4 cells, and with antiretroviral drug treatment allowing HIV-positive people to have undetectable levels of HIV in their system, it is never eliminated.
The hidden reservoir of HIV in cells, which cannot be detected with screening tools, would take hold of the immune system should patients stop their antiretroviral therapy.
The breakthrough means that the immune system’s T-cells should be able to detect HIV, since the cancer-fighting drug activates it from hibernation and pushes it into the bloodstream.
However, Søgaard said that while the immune systems of the HIV-positive people in his pilot study did not destroy the virus, a new trial with 20 people would use this approach combined with an experimental HIV vaccine, to possibly create a strong immune response to kill the virus.
He highlighted that this may not work if the virus still persisted in hidden reservoirs in cells, especially since his pilot study did not make it clear whether all or just some of the hidden cells had been activated, or “kicked out”, by the romidepsin drug.
The announcement at the conference came after discussion of the well-known case of the Mississippi baby, who was born to a HIV-positive mother and placed on a strong dose of antiretroviral drugs within 30 hours of birth.
The baby remained on treatment for 18 months and when it stopped, the HIV became undetectable in the baby’s system.
While it was hailed as a possible breakthrough in that infants treated early might be cured, 27 months later, it was reported that the virus was detected again and the Mississippi baby had returned to antiretroviral drugs.
Two Boston patients also received bone marrow transplants that appeared to rid them completely of HIV. However, like the Mississippi baby the virus returned and they are now back on antiretrovirals.
Most recently, it was reported that the levels of HIV in two Australian men were have reduced to undetectable levels following bone marrow transplants at Sydney’s St Vincent’s Hospital, but researchers have stopped short of declaring that case as a cure amid concerns the virus my only be dormant and could return if HIV medications are halted.