Researchers have found that a new combination immunotherapy, alongside antiretroviral therapy (ART), is effective in controlling and reducing simian immunodeficiency virus (SIV) in animals. The finding, say the researchers, may pave the way for additional treatment options to control HIV/AIDS.
ART is currently the most common treatment for HIV/AIDS. While it can reduce viral load to undetectable levels, it does not cure the condition. Moreover, ART is often expensive, requires a strict medication regime and is subject to social stigma. As such, researchers are working on alternative treatments for the condition to reduce reliance on ART.
For the study, the researchers worked with 16 SIV-positive, ART-treated rhesus macaques. In many non-human primates, untreated SIV infections progress into an AIDS-like disease and generate immune cells known as natural killer cells (NK cells) with impaired functionality.
During the study, the researchers compared animals only treated with ART to those who received ART, Interleukin-21 (IL-21) and interferon-alpha (IFN-alpha) to see how the combination treatment affected the animals’ viral load.
In the end, the researchers found that ART plus the immunotherapy combo-treated monkeys had improved NK cell responses when compared to those on ART alone. They also noted that the treatment reduced SIV replication in the lymph nodes, an area known to harbor the virus. Being able to target areas where the virus seeks refuge and limiting its ability to replicate, say the researchers, is essential for controlling HIV and preventing its progression into AIDS.
"This proof-of-concept study in rhesus monkeys, which progress to AIDS-like disease in the absence of ART, demonstrates how certain NK cell activity can contribute to controlling the virus," says Mirko Paiardini, PhD, one of the authors of the study.
"This opens the door to designing additional treatment strategies to induce SIV and HIV remission in the absence of ART, and, ultimately, reducing the burden HIV is to individuals, families and the world."