SEN virus infection influences the pathological findings in liver but does not affect the incidence of hepatocellular carcinoma in patients with chronic hepatitis C and liver cirrhosis

: Background/Aims: This investigation compared the histological findings in the livers of chronic hepatitis C patients who were or were not co-infected with SEN virus (SEN-V) to determine the histological and clinical characteristics of SEN-V infection in Japan. Methods: Three hundred and ninety-two patients with hepatitis C virus-associated chronic hepatitis (CH) or liver cirrhosis (LC) were included in the study. Serum samples were tested for the presence of SEN-V DNA by nested polymerase chain reaction. The liver biopsy specimen of each patient was examined and scores were assigned to indicate the severity of each of the following features: inflammatory cell infiltration in the periportal, parenchymal, and portal areas; F stage; portal sclerotic change; perivenular fibrosis; pericellular fibrosis; damage to the bile ducts; steatosis and irregular regeneration of hepatocytes (IR). Results: Of the 473 patients, 194 (41.0%) were positive for SEN-V DNA. The rate of progression of F stage correlated with SEN-V DNA positivity. The blood biochemical parameters did not differ significantly between the SEN-V DNA-positive and -negative patients. The histological features of the livers of SEN-V DNA-positive patients included more severe parenchymal inflammatory cell infiltration and more IR. In particular, among those at the F2, F3 and F4 stages, the degree of IR of the SEN-V DNA-positive patients was significantly greater than that of the SEN-V DNA-negative patients. The cumulative probability of hepatocellular carcinoma (HCC) incidence and survival rate did not differ between the SEN-V DNA-positive and-negative patients. Conclusions: SEN-V co-infection may influence the histopathological features of the livers of patients with type C CH and LC but does not affect the outcome of patients with type C chronic liver disease.