THE VALUE OF IDENTIFYING HEPATITIS C
positive after an ''open window phase'' variable in time from a few days to many months and are therefore,
VIRUS IN LIVER PATHOLOGY SPECIMENS
rarely helpful in the diagnosis of acute hepatitis C. Nouri-Aria KT, Sallie R, Mizokami M, Portmann BC, Third, despite their increasing sensitivity and specific-Williams R. Intrahepatic expression of hepatitis C viity, these tests are still hampered by false-negative and rus antigens in chronic liver disease. J Pathol false-positive results. Thus, the more sensitive method 1995;175:77-83.
to assess viremia is based on the detection of amplified HCV-RNA sequences using the polymerase chain reac-ABSTRACT tion (PCR). PCR methods are extremely complex and must be performed under carefully controlled condi-
of hepatitis C virus (HCV) antigens was tions. Even in highly specialized research laboratories studied in fresh frozen and formalin-fixed, paraffin-emfalse-positive and false-negative results have been docbedded liver tissue by immunoperoxidase using monoclonal antibodies to nucleocapsid protein and polyclonal umented, and great caution is to be observed in dealing human immunoglobulin G purified from plasma conwith PCR tests. 1 Fourth, PCR-negative serum does not taining antibodies to structural and non-structural antiexclude infection, because HCV-RNA has been obgens of hepatitis C virus. The results observed using served in liver tissue of serum HCV-RNA-negative pamonoclonal antibody to HCV core were similar to those tients. 2 This is particularly crucial for the diagnosis of of polyclonal IgG against HCV antigens in the majority HCV infection and in the evaluation of viral clearance of cases and both correlated well with HCV status as after treatment. Fifth, the pathogenesis of liver injury defined by 'nested' polymerase chain reaction. HCV antiin HCV infection and the determination of which cells gens were detected in both hepatocytes and mononusupport HCV replication is not clear. The reasons for clear cells. Using polyclonal human IgG, a small proporfrequent chronicity of HCV infection and for progrestion of biliary epithelial cells were also positive in 6/29
patients. In most of the specimens examined, relatively sion of its related liver diseases are not known. Finally, few cells (1-5 per cent) were found to be positive for HCV it is often difficult, if not impossible, to assess the role antigens. The cryostat sections, using polyclonal IgG of HCV in liver injury in multiple hepatotropic viral against HCV antigens; exhibited greater immunohistoinfections or when the clinical picture is complicated chemical staining, suggesting that the fixation and proby the presence of cryoglobulinemia or autoantibodies.