Dual infection with hepatitis B and C results in a competition.
The bodies of patients infected with both hepatitis B virus (HBV) and hepatitis C virus (HCV) respond to the diseases differently than those infected with only one of the two. A recent study conducted by Fei Chen, PhD, of the University of South China, and colleagues compared the virological and immunological features of patients with dual and single infections and found significant differences.
In some areas, among particularly high-risk populations, HBV/HCV dual infection is relatively common. The researchers noted that there is increasing evidence that such dual infections are more difficult to treat, and that there is a higher likelihood of disease advancement—from chronic hepatitis to cirrhosis and hepatocellular carcinoma. Previous studies seemed to indicate that dual infection has different virologic and immunologic profiles than single infections, but those studies have yielded inconsistent results.
The team recruited 1,049 injection drug users (IDUs) who were participating in a rehabilitation program between August 2014 and May 2015. The participants were divided into three groups: those with HBV single infection (136 patients); those with HCV single infection (340 patients); and those with dual infection (42 patients). The researchers performed serological tests, assessed viral load, and measured cytokine levels over the course of the study.
In considering replication, the researchers found that patients with dual infection had lower levels of HCV RNA than those with dual infection. However, the opposite was true for patients with HBV single infection compared to those with dual infection. In addition, HBV DNA levels were higher in the dual infection patients.
“Our results clearly suggest a competition between HBV and HCV infection when the liver is infected with both viruses, and HBV replication is dominant in dual-infected subjects,” the researchers wrote in Scientific Reports.
Because more people in the general population of China, where the study was conducted, are infected with HBV than HCV, and the infection pattern among IDUs is similar to that of the general population, the researchers think it is possible that the participants with dual infection were first infected with HBV. This would explain the differences in viral load among those with HBV single infection, HCV single infection, and dual infection.
Another finding of this study was that the anti-HCV antibody response was greater in those with HCV single infection than in those with dual infection. This could be due to the dual infection creating a heavier burden on the immune system of the host, weakening the antibody response to both viruses.
The researchers were unable to reach a clear conclusion regarding the expression of pro-inflammatory cytokines in patients with dual infection in this study.
“Taken together, our data may contribute to further understanding the biology of viral infection and immune response in patients with a dual infection of HBV and HCV,” the team concluded.
The study, “HBV/HCV dual infection impacts viral load, antibody response, and cytokine expression differently from HBV or HCV single infection,” was published in Scientific Reports.