MINNEAPOLIS, October 3, 2017 – A new study in the journal Nature Medicine suggests current antiretroviral therapies for the treatment of HIV infection are not making it into the tissues that contain most of the HIV infected cells at levels sufficient to completely suppress virus production.
According to the study, nearly 99 percent of HIV-infected cells are found in lymphoid tissue such as lymph nodes, spleen, and the gastrointestinal tract. Timothy Schacker, M.D., professor in the division of infectious disease and international medicine and director of the program in HIV medicine at the University of Minnesota Medical School, says that the large number of cells in this reservoir in people on therapy for several years pose a major challenge to curing HIV.
“These latently infected cells have the potential for reactivation and reigniting the infection if treatment is interrupted. But, the key finding was that we frequently found cells making viral particles in this reservoir in association with suboptimal concentrations of drugs in the tissues. Even ongoing low levels of virus production could certainly cause virus rebound on treatment interruption. So, if the goal is to stop virus production, we need better drugs that get into the lymphoid tissue reservoir.”
Schacker and a team of researchers analyzed tissues from before and after prolonged antiretroviral therapy used to treat the infection. The tissues included brain, gut, kidney, liver, lung, lymph node and spleen tissues from Rhesus Macaques infected with the simian immunodeficiency virus, a virus very similar to HIV, as well as lymph node and gut samples from humans infected with HIV.
Their analyses used imaging technology to show that a vast majority of the virus-producing and latently infected cells reside in the lymphoid tissue reservoir before, during and after antiretroviral therapies.
Looking ahead, Schacker, who is also associate director of the school’s Clinical and Translational Science Institute, says researchers need to understand why the current treatments do not achieve adequate levels in lymphoid tissue reservoirs to completely shut down virus production. This knowledge could jump-start the development of more effective treatments that could lead us closer to a cure for this disease.
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