HIV Inhibited By Herpes Drug In Patients Infected With Both Viruses
Researchers at the U.S. National Institutes of Health (NIH), McGill University and
other institutions have discovered how a simple antiviral drug developed decades ago suppresses HIV in patients who
are also infected with herpes. Their study was published in the Sept. 11 issue of the journal
Cell Host and Microbe.
An NIH research team led by Dr. Leonid Margolis made the initial discovery, while
Dr. Matthias Gotte, Associate Professor in Biochemical Virology at McGill's Department of Microbiology and
Immunology, along with colleagues at Emory University, helped explain the precise molecular
According to Dr. Gotte, HIV/herpes co-infection rates are very high and carry significant health burdens for
those patients who are already coping with HIV.
"In co-infected individuals, HIV disease progression is enhanced by the presence of herpes," he explained. "Why
this is the case is not clear, but there's a lot of evidence for it. Moreover, if you're infected with HIV and
herpes, it makes it easier for you to transmit HIV to other people. And if you're infected with herpes alone, it
makes it easier for you to acquire HIV."
Though it was long believed that acyclovir was an ineffective drug against HIV, it was often prescribed to
co-infected patients in the hope of indirectly treating HIV by reducing the herpes load. Surprisingly, the NIH team
discovered that in the presence of herpes virus HHV-6, acyclovir actually attacks HIV directly and is able to
suppress its reproduction.
Acyclovir is a "prodrug," which is converted into its active form only after it is administered to a patient. The
research team demonstrated that the herpes virus contains an enzyme not present in HIV and it is this enzyme that
converts acyclovir into a compound capable of attacking in HIV. Acyclovir by itself is simply inactive against HIV
and therefore the drug can only work in people infected with both viruses.
The researchers are hopeful this discovery may open a new front in the war on HIV, particularly in parts of the
developing world where rates of co-infection are extremely high.
"No anti-retroviral kills HIV completely," Dr. Gotte said. "We need to administer at least three drugs to
hold it in check. This potentially gives us another weapon in the armory, and it's cheap and accessible, which
matters a lot in the developing world."