Autoimmune forms of chronic hepatitis associated with hepatitis C virus (HCV) infection with and without HCV-RNA: Histological differences from pure autoimmune hepatitis and chronic hepatitis C

Liver biopsy specimens of pure autoimmune hepatitis (pAIH), autoimmune forms of chronic hepatitis with positivity for anti‐hepatitis C virus (anti‐HCV) and negativity for HCV‐RNA (cAIH‐RNA(–)), autoimmune forms of chronic hepatitis with positivity for anti‐HCV and HCV‐RNA (cAIH‐RNA(+)), and chronic hepatitis C (CHC) were compared histologically and statistically to clarify the histological character of the autoimmune form of chronic hepatitis with HCV infection. The following representative histological features were used to investigate: inflammation, fibrosis, plasma cell infiltration, lymphoid aggregates/follicles, non‐suppurative destructive cholangitis, and the shape of the enlarged portal tracts. While a considerable overlap in histological features between the pAIH and cAIH‐RNA(–) groups and between the CHC and cAIH‐RNA(+) groups was recognized, the overlap between the pAIH and CHC groups was small. Significant differences were found between cAIH‐RNA(–) and cAIH‐RAN(+) groups, especially in necroinflammatory findings. In conclusion, most cases of cAIH‐RNA(–) with histological features similar to those of pAIH were shown to be AIH. The remaining cases might be CHC with subsidence of viral duplication. Conversely, many cases of cAIH‐RNA(+) with histological findings similar to those of CHC were shown to be CHC clinically mimicking pAIH. The remaining cases might represent coexistence of pAIH and HCV infection.