For patients infected with both HIV and hepatitis C, HIV antiretroviral therapy may help control both viruses, a small study suggests. Researchers said doctors could use their findings to improve treatment strategies for people with the two diseases.“The findings suggest that HIV suppression with antiretroviral medications plays an important role in the management of individuals with [hepatitis C] and HIV infection,” said study leader Dr. Kenneth Sherman, a professor of medicine at the University of Cincinnati College of Medicine. “It supports the concept that in those with HCV/HIV infection, early and uninterrupted HIV therapy is a critical part of preventing liver disease.”

The researchers conducted the study to address concerns that treating patients who have HIV — the AIDS-causing virus — and hepatitis C with HIV antiretroviral therapy would damage the liver and cause more harm than good.

To put this theory to the test, they closely examined 17 patients infected with both viruses for two years. The patients received approved HIV antiretroviral drugs. They were also examined frequently, and their blood was routinely tested to track any changes in the viruses and their immune response.

The findings were published July 23 in the journal Science Translational Medicine.

Some patients experienced an initial increase in a blood test that shows changes in liver injury, hepatitis C or both in the first 16 weeks of the study.

Over 18 months, however, the study revealed that “viral loads” for hepatitis C dropped back down to levels expected for a patient infected with only hepatitis C and not HIV.

“The drop in [hepatitis C] viral levels was a big surprise, and not what we necessarily expected,” said Sherman in a university news release. “There is a complex interaction of biological effects when patients are infected with both HIV and the hepatitis C virus.” He explained that initially HIV treatment results in a transient increase in hepatitis C viral replication and evidence of liver injury. However, over time, HIV suppression leads to reduced hepatitis C viral replication.

In the United States, up to 300,000 people are infected with both hepatitis C and HIV. Globally, that number increases to between 4 million and 8 million, the researchers said.