Effect of antiretroviral HIV therapy on hepatitis B virus replication and pathogenicity.

Coinfections with hepatitis B virus (HBV) and HIV are very frequent. Although HBV is a DNA virus, it replicates via reverse transcription like HIV. Structural similarities between the enzymatic pocket of the HBV DNA polymerase and HIV-1 reverse transcriptase are the basis that certain drugs inhibit both enzymes and thus the replication of both viruses. HBV components increase the pathogenic action of HIV and vice versa directly by certain proteins like HBsAg in the case of HBV and HIV-encoded Tat and Vpr and by disturbing the cytokine balance in affected cells. Antiretroviral therapy is highly beneficial for HIV/HBV-coinfected patients, but carries the risk of drug-induced resistance development and hepatotoxicity. Even with restoration of the immune capacity, signs of hepatic inflammation may develop even after 10 years of treatment.