Evidences of Hepatitis C Virus Replication in Hepatocytes and Peripheral Blood Monocuclear Cells from Patients Negative for Viral RNA in Serum

Juan Morales,Viviana Falcon,Eduardo Vilar,Magdalena Miranda-Sa,Victor Tsutsumi,Bienvenido Gra,Celia Fernandez-,Juan Kouri,Nelson Acosta-Riv,Maria-C De La Rosa,Ivon Menendez,Santiago Duenas-Car,Jose Silva,Dionne Casillas,Jose Luna-Munoz,Deliana Lopez,Maritza Gonzalez-B,Waldo Garcia

doi:10.3844/ajidsp.2005.34.42

Abstract

In this study, we examined the expression of hepatitis C virus (HCV) components in hepatocytes and peripheral blood mononuclear cells (PBMC) from patients positive for anti-HCV antibodies and negative for serum HCV-RNA. The samples obtained from 25 randomly selected patients (13 of 25 patients showed no histological evidences of chronic hepatitis and had normal serum ALAT and GGTP levels) were studied by in situ Hybridization and Immunofluorescence assays. The findings show that HCV-RNA of both positive and negative polarity was carried in the hepatocytes of more than 80% of cases. The proportion of cells expressing the negative strand (mean ± SD, 10.25% ± 5.56%) was lower than those expressing positive strand (mean ± SD, 19.88% ± 9.19%) (p=0.0076; Student’s t test). In addition, reaction products suggestive of HCV core, E1 and E2 antigens within hepatocytes were also observed. Both hybridization and immunofluorescence signals were localized in the cytoplasm suggesting that this is the place of active HCV replication. On the other hand, the HCV-RNA of positive polarity was detected in PBMC from 16 out of 17 samples analyzed (94%) while the HCV-RNA of negative polarity was detected in 82% of samples investigated. Positive hybridization signals were localized in the cytoplasm of PBMC. Interestingly, 12 out of 13 patients with clinical and histological resolution of hepatitis, contain HCV-RNA in either liver or PBMC. These results provide further evidences that the intermediate replicative form of the HCV genome can persist in hepatocytes and PBMC after apparently complete resolution of chronic hepatitis C.

Highlights

Hepatitis C virus (HCV) infection is a major public health problem world wide
Detection of HCV-RNA in liver biopsy samples: in situ hybridization (ISH) analysis of liver biopsies from 3 chronically HCVinfected patients used as positive controls showed both positive and negative strands of the HCV genome localized in the cytoplasm of hepatocytes (Fig. 1A,B, Table 1)
The specificity of the ISH reaction for HCV-RNA was confirmed by the failure to detect a positive signal when either an unrelated probe was used (Fig. 1D) or when the biopsy sections from HCV-infected patients were predigested with RNase A before hybridization with HCV-1 and HCV-2 probes (Fig. 1E,F)

Summary

Introduction

Hepatitis C virus (HCV) infection is a major public health problem world wide. HCV is considered the causative agent of a wide spectrum of liver diseases, including posttransfusion non-A non-B hepatitis, chronic hepatitis and cirrhosis and primary hepatocellular carcinoma[1,2]. Diagnosis of HCV relies on either indirect serological detection of anti-HCV antibodies by enzyme-linked immunosorbent assay (ELISA) supplemented with recombinant immunoblot assay (RIBA) or directly through the detection of HCV-RNA in serum by reverse-transcription nested polymerase chain reaction (RT-PCR)[6]. Very sensitive, these assays do not allow for cell-specific localization of HCV. These assays do not allow for cell-specific localization of HCV Other assays such as in situ hybridization (ISH), immunohistochemistry (IHC) and immunofluorescence (IF) have been used for the localization of HCV genome and gene products inside HCV-infected cells[7,8,9]

Methods

Results

Conclusion