Chronic hepatitis in multiple virus infection: histopathological evaluation.

The frequency and histological pattern of multiple hepatitis virus infection was studied in 161 Italian patients who had consecutively undergone liver biopsy from 1989 to 1991. The histological features were compared with that of infection with a single virus. Thirty-nine per cent of patients had evidence of past or present multiple infection, the commonest of which was hepatitis C virus (HCV) in patients with evidence of previous infection with hepatitis B virus (HBV). In general, the severity of the histological pattern of each viral infection was maintained even when more than one virus was involved; there was neither exacerbation nor diminution of the histological changes. The delta-virus (HDV) was not associated with severe necro-inflammatory lesions, but HDV-positive patients were few in this cohort. Lymphoid follicle formation (a putative histological marker of HCV infection) was also found in a high proportion of HCV-negative patients but expressing much HBcAg or HDAg in liver tissue. Possible explanations for this finding are that follicles are relatively non-specific for HCV infection, or that these cases represent HCV infection with false-negative serology. The results of this study suggest that multiple hepatitis virus infection is common in the population investigated and that HBV and HCV co-infection cannot be reliably diagnosed histologically. Whether double infection with these viruses influences the cirrhotic evolution of the liver lesion remains unclear.