Interactions between alcohol and hepatitis viruses in the liver.

There is a high frequency of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among individuals with alcoholic liver disease (ALD) and alcohol-associated hepatocellular carcinoma (HCC), suggesting that these viruses are implicated in the pathogenesis of these diseases. Alcohol may act synergistically by promoting the development and progression of liver disease. The interactions of alcohol with infected hepatocytes and with antiviral immunity may result in altered patterns of virus gene expression and replication, making diagnosis difficult in some cases of ALD and HCC. The potential association of ALD and alcoholic HCC with serologically negative virus variants raises major difficulties in the epidemiologic assessment of cause and effect, providing major challenges for the future.