Comparative study between occult hepatitis C virus infection and chronic hepatitis C.

We have recently described the presence of occult hepatitis C virus (HCV) infection (HCV-RNA in liver in the absence of anti-HCV and serum HCV-RNA) in patients with persistently abnormal liver function tests of unknown aetiology. The aim of this study was to compare the characteristics of patients with occult HCV infection vs those of patients with chronic hepatitis C. We compared clinical features of 68 patients with occult HCV infection and 69 untreated chronic HCV patients (anti-HCV and serum HCV-RNA positive), matched for age, gender, duration of abnormal liver function tests and body mass index. Aspartate aminotransferase and alanine aminotransferase were higher (P < 0.001) in chronic HCV, but cholesterol and triglycerides were significantly higher in patients with occult HCV infection (P < 0.001 and P = 0.002). Chronic HCV patients had higher gamma-globulin (P = 0.005), alpha-foetoprotein (P < 0.001) and iron (P < 0.001) levels. Percentage of patients with necroinflammatory activity and fibrosis was higher (P < 0.001) in chronic HCV than in occult HCV infection. Mean percentage of infected hepatocytes was higher (P = 0.001) in chronic HCV (10.1%) than in occult HCV infection (5.3%). This occult HCV infection is a milder disease than chronic HCV, and this could be related to the significantly lower number of infected hepatocytes observed in occult HCV.