Effects of alcohol on the replication of hepatitis C virus.

We have reported that hepatitis C virus (HCV) RNA encoding the NS5 region (HCV-NS5) became negative following abstinence in some patients with alcoholic liver disease (ALD). In order to clarify the relationship between alcohol misuse (abuse) and the replication of HCV, serial changes of HCV-NS5 and the titer of HCV (HCV-titer) in blood after abstinence were studied in 11 male patients with ALD. Disappearance of HCV-NS5 after abstinence was found in five out of 11 patients (45%) and HCV-titer in blood decreased in all of these cases. In one patient, HCV-NS5 became positive and HCV-titers increased again following resumption of alcohol misuse. The etiology of liver disease in heavy drinkers was subdivided into three categories: alcohol alone, alcohol and HCV, and HCV alone, according to the diagnostic criteria of the Japanese research group for ALD. The etiology in four patients was a combination of alcohol and HCV, and was HCV alone in the remaining seven patients. In all four patients of the alcohol and HCV group, and one out of seven patients in the HCV alone group, HCV-NS5 became negative and HCV-titer decreased after abstinence. The decrease in HCV-titer was not related to the HCV genotypes. These results suggest that alcohol misuse may enhance the replication of HCV.