Comparison of several PCR procedures for detection of serum HCV-RNA using different regions of the HCV genome

Hepatitis C virus replicates in sweat glands and is released into sweat in patients with chronic hepatitis C

Hepatitis C virus (HCV) replicates in salivary glands of chronic hepatitis C patients and is released into the saliva, suggesting that HCV may replicate in other exocrine glands. The presence of positive and negative HCV RNA strands was demonstrated by in situ hybridization, and of HCV core protein by immunohistochemistry, in sweat glands and keratinocytes in healthy skin biopsies from 15 patients with chronic hepatitis C and 10 anti-HCV negative patients with chronic liver disease. Positive and negative HCV RNA strands were detected in 9.6 +/- 5.2% and 4.2 +/- 3.8%, respectively, of the epithelial cells of eccrine sweat glands. Core protein was detected in 6.0 +/- 3.93% of these cells. HCV RNA resistant to RNase digestion (encapsidated HCV RNA) was detected in 10/10 sweat samples from HCV-infected patients. Positive and negative HCV RNA strands were detected in 6.7 +/- 2.97% and 3.0 +/- 3.08% of the keratinocytes, respectively. HCV core protein was found in 4.5 +/- 2.76% of these cells. No HCV RNA or HCV core protein was detected in the skin biopsies from the 10 anti-HCV negative patients. In conclusion, HCV replicates in eccrine sweat glands cells and keratinocytes in healthy skin and is released into the sweat.

Incidence of hepatitis C virus RNA in anti-HCV negative plasma pools in Croatia

The risks of transmitting viral infection by blood and products derived from plasma have long been known and still remain an area of concern. Blood banks and transfusion centres are faced with the imminent introduction of nucleic acid amplification testing (NAT) of plasma pools as used by the plasma industry. In this paper, we show a part of our results of a validation study of an in-house method for routine polymerase chain reaction (PCR) screening for hepatitis C virus (HCV) RNA in plasma pools and the results of testing 2,718 anti-HCV negative plasma pools for the presence of HCV RNA. The European Committee for Proprietary Medical Products (CPMP) recommended that from 1 July 1999, only batches derived from plasma pools tested and found non-reactive for HCV RNA, using validated test methods of suitable sensitivity and specificity, should be batch released by authorities. The quality and efficiency of NAT detection of HCV RNA is among others influenced by the efficacy of RNA isolation, the primer selection and the use of control samples. Using modern molecular biology techniques (sensitive and specific in-house amplification methods for detection of HCV RNA and automated sequencing), we analysed samples of plasma pools from different Croatian transfusion centres. By detection of HCV RNA in an NIBSC working reagent (genotype 3) and a Pelispy HCV RNA run control (genotype 1) we determined a high reproducibility and sensitivity (below 100 International Units (IU)/ml) for our in-house method. By direct sequencing PCR cDNAs we proved the specificity of the test system and the possibility of determining the HCV genotype when the method was used for PCR screening of HCV RNA in single donations. Of 2,718 anti-HCV negative plasma pools we have found that 2.1$ were HCV RNA positive. Results of our investigation confirm the necessity of testing HCV RNA in plasma pools to further increase the safety of human plasma-derived drugs.

TT virus detection in oral lichen planus lesions

Epidemiological studies have demonstrated a correlation between oral lichen planus and different liver diseases. The new virus termed TT virus (TTV) is highly prevalent in patients with chronic hepatitis of different etiology and it may be speculated that TT virus may be involved in the pathogenesis of oral lichen planus. This study examined the presence of TT virus DNA in serum by PCR and in oral mucosa biopsies by in situ hybridization from 20 patients with oral lichen planus (13 with chronic hepatitis and seven without liver disease). Serum and oral mucosa biopsies from six patients all with chronic hepatitis with leukoplakia were also studied as controls. TT virus DNA was positive in the serum of 17/20 (85%) of the patients with oral lichen planus and in all the controls. TT virus DNA hybridization signals were detected in mucosa biopsies from all the patients with TT virus DNA in serum but in none of the three cases without this marker. The percentage of positive cells ranged from 1.6-80%. No differences were found in the percentage of positive cells between TT virus positive patients with and without oral lichen planus and there was no relationship between the number of positive cells and the intensity of the inflammatory infiltrate. In conclusion, TT virus infects oral epithelial cells but the results do not support a role for TT virus in causing oral lichen planus.

In situ detection of hepatitis C virus RNA in salivary glands

Chronic hepatitis C virus (HCV) infection has been associated with several extrahepatic manifestations, among these, to diseases with oral manifestations such as Sjögren's syndrome or sialadenitis. HCV-RNA has been detected in saliva and in salivary glands from patients with sialadenitis by polymerase chain reaction. However, morphological evidence of HCV replication in salivary gland cells is needed to support a role for HCV in causing sialadenitis or Sjögren's syndrome. We have used in situ hybridization and immunohistochemistry to analyze the presence of HCV-RNA of sense and antisense polarity and HCV core antigen, respectively, in salivary gland biopsies from 19 patients with chronic sialadenitis or Sjögren's syndrome (eight anti-HCV-positive; 11 anti-HCV-negative). HCV-RNA of both positive and negative polarity as well as HCV core antigen were detected in the epithelial cells of the salivary gland biopsies from all of the anti-HCV-positive patients but in none of the anti-HCV-negative cases. The percentage of HCV-infected cells ranged from 25 to 48.8% in the patients studied. In conclusion, we have shown that HCV infects and replicates in the epithelial cells from salivary glands of patients with Sjögren's syndrome or chronic sialadenitis. However, its implication in the pathogenesis of these diseases deserves future research.

Genomic and phylogenetic analysis of hepatitis C virus isolates from argentine patients: a six-year retrospective study

Typing of hepatitis C virus (HCV) isolates from Argentine patients was performed by using different methodologies in a population of 243 patients. HCV subtype was assigned based upon restriction fragment length polymorphism (RFLP). HCV RNA genomes obtained from serum samples were classified as belonging to clade 1 (53.5%), 2 (23. 0%), or 3 (8.6%); 14.8% of samples showed HCV mixed infections, more frequently implying different subtypes within the same clade. In addition to RFLP typing, phylogenetic relatedness among sequences from both 5' untranslated region (n = 50) and nonstructural 5B coding region (n = 15) was established.

Detection of hepatitis C virus replication by In situ hybridization in epithelial cells of anti-hepatitis C virus-positive patients with and without oral lichen planus

Epidemiological studies have demonstrated that there is a correlation between oral lichen planus and chronic hepatitis C virus (HCV) infection. HCV RNA has been recently detected in epithelial cells from oral lichen planus lesions by reverse-transcription polymerase chain reaction (RT-PCR). However, this technique does not discriminate which types of cells are infected by the virus or if the viral RNA is present in the serum that contaminates the biopsy. Morphological evidence of viral replication in cells from these lesions is needed to establish a role for HCV in oral lichen planus. Consequently, we have analyzed the presence of positive and negative HCV-RNA strands in oral mucosa biopsies from 23 patients (14 anti-HCV-positive) diagnosed as having oral lichen planus and from 5 patients with chronic hepatitis C without oral lichen planus. Positive and negative HCV-RNA strands were detected in epithelial cells of the mucosa biopsies from all anti-HCV-positive patients independently of whether or not they had oral lichen planus, but in none of the anti-HCV-negative cases. The percentage of stained cells ranged from 4.4% to 14.3%. These percentages do not correlate with the serum viremia levels or the intensity of the cellular infiltrate in patients with oral lichen planus. In conclusion, we have shown that HCV replicates in epithelial cells of patients with and without oral lichen planus. The pathological consequences of this finding remain to be elucidated.

Lessons from a multicentre study of the detectability of viral genomes based on a two-round quality control of GB virus C (GBV-C)/hepatitis G virus (HGV) polymerase chain reaction assay

The aim of this study was to determine whether multicentre quality controls for the detectability of viral genomes could contribute to the improvement of diagnostic performance in the participating laboratories. The study was carried out during two successive rounds, during which 18 laboratories specialized in nucleic acid testing analyzed, through a polymerase chain reaction (PCR) assay, a common panel of GB virus C (GBV-C)/hepatitis G virus (HGV) RNA-positive and -negative samples. During the first round, the laboratories used either an 'in-house' PCR procedure or a partly standardized commercial test. After decoding the results of the first round, the procedures of the participating laboratories were compared in order to establish a consensus procedure deduced from those of the laboratories which provided the best results. During the second round, each participating laboratory could use the resulting consensus procedure, or its own procedure, or both. The results of this quality control study indicated that, whatever method used, even specialized and trained laboratories may give false-negative or false-positive results. The commercial assay did not guarantee a systematic high quality level of results. The striking heterogeneity of results observed among laboratories using the same commercial assay confirm that molecular biology methods need skilled technicians. The results of this quality control study suggest that full standardization of viral genome detection, including all steps of the procedure, is necessary and that the laboratories performing PCR should participate in repeated quality control studies, whatever technique is being used.

Hepatitis C virus RNA in kidney biopsies from infected patients with renal diseases

Hepatitis C virus (HCV) infection has been associated with several renal pathologies, including membranoproliferative and membranous glomerulonephritis. Although the presence of HCV proteins has been reported, there are no data concerning detection of the viral RNA in renal cells from HCV-infected patients with kidney disease. In this report we analysed, by in situ hybridization, the presence of HCV RNA in renal biopsies from 10 patients who were positive for antibodies to HCV (anti-HCV) and serum HCV RNA positive, and from four patients without HCV infection, with different renal disease. HCV RNA was detected in the renal biopsies from all of the 10 HCV-infected patients. Hybridization signals were detected in the tubular and capillary endothelial cells. No hybridization signals were found in the renal biopsies of the four anti-HCV-negative patients. In conclusion, our results demonstrate that HCV RNA is common in kidney cells of patients with renal diseases who are infected with HCV. The presence of HCV RNA is not necessarily associated with a pathogenetic consequence.

Clinical use of hepatitis C virus tests for diagnosis and monitoring during therapy

This article reviewed various methods used for the diagnosis and monitoring of HCV infection and discusses potential clinical applications. Substantial improvements have recently been made in assay technology. Moreover, the role of molecular testing in the clinical setting of hepatitis C is becoming better defined. The major challenge facing clinical laboratories is the further refinement, implementation, and standardization of optimized molecular tests, so that reliable data may be made available to clinicians. In turn, clinicians must understand the limitations of each methodology, including the variability of testing that may occur among different laboratories. As more experience is gathered, molecular testing will probably provide important data regarding the most effective use of current and future therapies for individual patients to achieve maximum benefit in the management of hepatitis C.

Multigene tracking of hepatitis C virus quasispecies after liver transplantation: correlation of genetic diversification in the envelope region with asymptomatic or mild disease patterns

To investigate the role of hepatitis C virus (HCV) quasispecies mutation in the pathogenesis of HCV infection, we analyzed changes in the genetic diversity of HCV genomes in 22 patients before and after liver transplantation by using heteroduplex mobility assay (HMA) technology. All patients were infected with HCV genotype 1 and developed high-titer posttransplant viremia. Each patient was classified according to the severity of posttransplant hepatitis, as assessed by standard biochemical and histological criteria. HCV quasispecies were characterized by HMA analysis of eight separate subgenomic regions of HCV, which collectively comprise 44% of the entire genome. The glycoprotein genes E1 and E2, as well as the nonstructural protein genes NS2 and NS3, had the greatest genetic divergence after liver transplantation (the change in the heteroduplex mobility ratio [HMR] ranged from 2.5 to 7.0%). In contrast, genes encoding the core, NS4, and NS5b proteins had the least amount of genetic divergence after liver transplantation (range, 0.3 to 1.2%). The E1/E2 region showed the greatest change in genetic diversity after liver transplantation, and the change in HMRs was 2.5- to 3.3-fold greater in patients with asymptomatic or moderate disease than in those with severe disease. The E1-5' region of HCV quasispecies isolated from patients in the asymptomatic group had a significantly greater degree of diversification after liver transplantation than the same regions of HCV quasispecies isolated from patients in the severe disease group (P = 0.05). While changes in the genetic diversity of some nonstructural genes were also greater in asymptomatic patients or in patients with mild disease than in patients with severe disease, the results were not significant. Data from this cohort demonstrate that greater rates of HCV quasispecies diversification are associated with mild or moderate liver disease activity in this immunosuppressed population.

Relative quantification and mapping of hepatitis C virus by in situ hybridization and digital image analysis

Although several reports concerning the detection of hepatitis C virus (HCV) by in situ hybridization have been published, there are no data concerning the relative viral load in infected hepatocytes or about its relation with serum viremia levels. To address these issues, liver biopsies from 10 patients with chronic hepatitis C were analyzed by in situ hybridization and digital image analysis of hybridization signals. Serum HCV RNA levels were measured using the Amplicor Monitor test. HCV RNA was detected by in situ hybridization in the hepatocytes of the ten liver samples. The hybridization signals were mainly found in the cytoplasm. The relative viral load per infected cell fit the second order polynomial curves in all cases. The minimum and maximum relative viral load per infected hepatocyte differed in the ten cases; however, large differences were not observed in the mean relative viral load among the samples, especially when compared with the increasing values detected for copy number per milliliter in serum. The percentage of infected cells ranged from 4.8% to 87.6% in the ten cases. The percentage of positive cells correlated with the serum viremia levels. Our data suggest that HCV viremia does not depend on the relative viral load per infected cell but on the number of infected hepatocytes.

Rapid detection of different RNA respiratory virus species by multiplex RT-PCR: application to clinical specimens

BACKGROUND

The polymerase chain reaction (PCR) applied in diagnostic and epidemiologic investigations is very useful for sensitivity, specificity and time saving.

OBJECTIVE

We have developed a method for the detection of genomic RNA of two different species of virus, the influenza A virus (IA) and the respiratory syncytial virus (RS), which are responsible for clinical similarities. We applied this multiplex RT-PCR protocol on clinical specimens.

STUDY DESIGN

We describe a method which allows rapid diagnosis by performing a single retro-transcriptase (RT) reaction associated with the PCR (multiplex RT-PCR) on different genomes in a single sample. We have evaluated the sensitivity and the specificity of the multiplex test on positive controls, then, on RNA extracted from clinical specimens harvested from 15 children with respiratory symptoms during the spring-winter season 1997.

RESULTS AND CONCLUSIONS

The multiplex RT-PCR protocol, applied to respiratory specimens, allows the investigation of RNA IA virus and RS virus in a single sample at the same time. The detection of the etiologic viral agent is rapid and it is possible to evaluate incidental simultaneous infections.

Effects of formalin fixation and prolonged block storage on detection of hepatitis C virus RNA in liver tissue

It has been suggested that prolonged formalin fixation and block storage adversely affect hepatitis C virus (HCV) ribonucleic acid (RNA) detection in tissue by reverse transcriptase-polymerase chain reaction (RT-PCR). We attempted to determine whether short-term perfusion fixation (3-5 days) or prolonged formalin storage adversely affects the detection of HCV RNA in paraffin-embedded tissue in comparison with 24-h fixation. Also, we examined the effects of prolonged storage of paraffin blocks on the sensitivity for HCV detection. We performed RT-PCR in formalin-fixed explanted livers from 20 liver allograft recipients known to be HCV positive (10 with specimens stored for 2-4 years and 10 with specimens stored for > 4 years). We compared the results of perioperative needle liver biopsy specimens fixed overnight with liver sections fixed by perfusion for 3-5 days and bulk liver tissue stored in formalin for years (mean, 6.25 years; range, 2-11 years). HCV RNA was detected in 100%, 85%, and 0% of specimens fixed for 24 h, 3-4 days, and years, respectively. We conclude that HCV can be readily detected in tissue fixed by formalin overnight, sensitivity decreases slightly with intermediate-length fixation, and HCV is rendered undetectable by prolonged fixation. In addition, retention of formalin-fixed tissue in paraffin blocks does not affect the sensitivity of HCV detection.

Cloning, expression, purification, and characterization of the major core protein (p26) from equine infectious anemia virus

The gene coding for the major core protein (p26) of the lentivirus equine infectious anemia virus (EIAV) was cloned from EIAV infected serum, expressed in E. coli, and the resultant protein purified to electrophoretic homogeneity. The protein was expressed in a soluble form and was purified by conventional protein separation methods. When analyzed by SDS-PAGE, under both reducing and non-reducing conditions, the purified protein migrated as a 26 kDa monomer. Recombinant p26 (rp26), therefore, does not contain any intermolecular disulfide bond. Gel filtration chromatography also indicated that the protein occurs as a monomer in solution. Labeling of free sulphydryl groups with [1-14C]iodoacetamide suggests that none of the three cysteine residues of rp26 is involved in intramolecular disulfide bonds. The circular dichroism spectrum of rp26 was consistent with the following assignment of secondary structure elements: 51% a-helix, 15% beta-turn, and 34% aperiodic. Fluorescencespectroscopy revealed that the three tryptophan residues in rp26 occupy two different environments. These data support the conclusion that the recombinant protein is folded into an ordered and probably native conformation. Immunoblotting and enzyme immunoassay with EIAV infected sera demonstrated that recombinant p26 protein may be useful for diagnostic purposes.

Decreased nitric oxide production in chronic viral hepatitis B and C

Nitric oxide is a free radical gas molecule which may be implicated in antiviral defense. However, there is no information about its possible role in chronic viral hepatitis B and C. In this study we have analyzed the serum levels of NO2- (as an index of nitric oxide generation) from patients with chronic viral hepatitis B and C and relationship of same with the response to interferon therapy. Serum samples were analysed from 61 patients with chronic hepatitis B, 60 patients with chronic hepatitis C, 11 with chronic liver disease of nonviral origin, and 23 healthy controls. Levels of NO2- were statistically higher in healthy controls (P < 0.001) than in patients with chronic liver disease. No relation was found between NO2- and viremia or response to interferon therapy in patients with chronic hepatitis B. In contrast in chronic hepatitis C, responder patients had significantly higher NO2- than nonresponders (P < 0.01). With respect to the relation between NO2- levels and liver damage, patients with cirrhosis had lower NO2- levels than the rest of the patients (P < 0.001). In conclusion, patients with chronic viral hepatitis have low serum NO2- levels.

Rapid and sensitive genotyping of hepatitis C virus by single-strand conformation polymorphism

There is an increasing demand for genotyping hepatitis C virus (HCV) isolates due to the rapidly expanding list of distinct HCV genotypes and the mounting evidence of genotype-specific clinical consequences. We describe an SSCP-based assay for determining genotypes in HCV infections. HCV RNA extracted from serum was amplified by a sensitive nested-PCR assay producing a 287 bp fragment of the conserved 5' non-coding region (NCR) and analysed by non-denaturing polyacrylamide gel electrophoresis. Following empirical optimisation of the SSCP assay we identified distinct conformation polymorphisms (characteristic band patterns) corresponding to types 1a, 1b, 2a, 2b, 2c, 3 and 4 found in the Western Australian population. Seventy-three HCV RNA-positive samples were used to evaluate the SSCP genotyping assay for accuracy and efficiency by comparison with the previously established genotyping methods of manual direct sequencing and dideoxy fingerprinting. SSCP genotyping was in concord with control methods while performing more rapidly and at a fraction of the cost. Moreover, SSCP detected two co-infected samples that were not shown by the control methods. The PCR-SSCP assay provides an accurate and rapid method for genotyping of HCV RNA-positive samples at the 5' NCR by type-specific sequence polymorphisms which is applicable to large-scale screening.

Undiagnosed hepatitis C virus infection in hemodialysis patients: value of HCV RNA and liver enzyme levels

At present, routine screening for hepatitis C virus (HCV) infection is based on the detection of antiviral antibodies. Underdiagnosis of HCV infection by using HCV antibody tests, however, still occurs. Additional diagnostic means are provided by the polymerase chain reaction (PCR). The measurement of aminotransferase (ASAT and ALAT) has served as an auxiliary, less specific test. The present research aimed to design practical and low cost strategies to diminish underdiagnosis of HCV infection in dialysis patients. With this purpose in mind, we examined whether aminotransferases values in HCV antibody-negative patients could be related to undiagnosed HCV infection, by using HCV RNA testing by PCR as the gold standard. In 112 hemodialysis patients, we found 78 negative and 34 positive for HCV antibodies. A major finding was that 222 (28.2%) out of the 78 HCV antibodies-negative patients had positive HCV RNA by PCR. In repeated samples taken at six months follow-up from 19 out of these 22 patients, only one of them was positive for anti-HCV antibodies; moreover, a positive HCV RNA by PCR was confirmed in 13 (68.5%) of them. Within the HCV antibody-negative group, the mean values of ASAT, ALAT and gammaglutamiltransferase were higher (P < 0.001, P < 0.001 and P < 0.02, respectively) in the HCV PCR-positive versus the HCV PCR-negative patients. No significant differences were found in the liver enzyme values between the HCV antibody-negative, HCV RNA positive and the HCV antibody positive, HCV RNA positive individuals. Histological samples from two HCV RNA positive, HCV antibody-negative patients disclosed the presence of a mild liver disease. In conclusion, the present study demonstrates the critical importance of HCV RNA determination by PCR in hemodialysis patients who have no detectable circulating antibodies against the HCV. Furthermore, in conditions in which PCR technology is not readily available, we have established that the existence of a moderate increase of aminotransferases is a helpful clue to detect patients with absent HCV antibodies, and might represent an useful, low cost tool for HCV screening in dialysis patients.

Mixed cryoglobulinemia secondary to hepatitis C virus infection

Mixed cryoglobulinemia is a systemic vasculitis with clinical manifestations ranging from the characteristic benign-appearing syndrome of palpable purpura, arthrologies, and fatigue to severe vasculitis involving vital organs. A strong association of the disease with hepatitis C virus infection and the demonstration of the specific concentration of the virus in the cryoglobulins have implicated hepatitis C virus in the etiopathogenesis of the disease. The increase in illicit intravenous drug use in the past 30 years seems to have raised the occurrence in the United States of this once uncommon disease and changed the demographics: there seem to be more male intravenous drug users in their forties with the disease than women without risk factors for hepatitis C virus infection in their fifties and sixties. Pathogenesis, therapy, and the hypothesis on the etiologic role of hepatitis C virus are reviewed, and the implications of recent studies and new concepts for treatment of this often benign-appearing but deceptive and potentially life-threatening disease are discussed.

Nested polymerase chain reaction for detection of hepatitis C virus RNA in blood derivatives

Testing for the presence of hepatitis C virus (HCV) in blood derivatives used in clinical medicine is of enormous importance to ensure the production of safe preparations. So far, no system has been developed for the isolation and detection of hepatitis C virus from blood derivatives. The recently introduced commercial kit for the detection of hepatitis C virus is designed for the isolation and detection of virus from blood serum. A reliable and reproducible method for the isolation of hepatitis C virus RNA, subsequent reverse transcription and nested polymerase chain reaction (PCR) from blood derivatives is described. Of 17 batches of factor VIII, gamma-globulin and anti tetanus, cytomegalovirus and Varicella-zoster immunoglobulin concentrates, respectively (14 negative for anti HCV and 3 of unknown anti HCV status) five were found positive in RNA-PCR.

Detection of hepatitis C virus RNA by a reliable, optimized single-step reverse transcription polymerase chain reaction

A single-step reverse transcription polymerase chain reaction (SRT-PCR) method was optimized for hepatitis C virus (HCV) RNA detection. Extraction procedures by proteinase K and guanidinium isothiocyanate gave similar results. The optimal MgCl2 concentration for the SRT-PCR method was 2 mM with 10 units of superscript M-MLV RNase H-reverse transcriptase and 1 unit of Taq polymerase. Shorter PCR cycling steps gave a 10-fold-increased PCR product compared with longer cycling steps. Twenty-five anti-HCV-positive sera from chronic hepatitis C patients were positive with SRT-PCR, whereas only 17 out of 25 were positive by dissociated RT and PCR (dRT/PCR). Specificity was assessed by twenty negative controls. SRT-PCR was 5-fold more sensitive (5 HCV RNA copies per assay) than dRT/PCR with an HCV RNA transcript. Our SRT-PCR method for HCV RNA detection appears fully adapted for routine use in a medical virology laboratory.

Identification of hepatitis C virus by immunoelectron microscopy

Sequencing of the hepatitis C virus (HCV) has provided a better understanding of the natural history, immunology, and epidemiology of this virus. However, the morphology of HCV has not been definitively characterized. In this study, through a sequence of concentration processes, virus-like particles were isolated from human serum and liver tissue, visualized by transmission electron microscopy and identified as hepatitis C virion by immunoelectron microscopy. Spherical flavi-like virus particles, approximately 70 nm in diameter, were observed in the fraction with 1.04-1.12 g ml-1 sucrose density and bound to immunogold particles with monoclonal antibodies (mAb) against hepatitis C. The nucleocapsid of the particles, which were 50 nm in diameter, appeared to be icosahedral in structure and surrounded by an envelope covered with surface projections. A 'tadpole' form of particles was also observed. The findings indicate that the low buoyant density in sucrose and the morphological features of the hepatitis C virion are consistent with the characteristics of flaviviruses and pestiviruses.

Single-step reverse transcription-polymerase chain reaction for hepatitis C virus RNA with DNA enzyme immunoassay hybridization

A single reverse transcription-polymerase chain reaction (SRT-PCR) for HCV RNA detection, confirmed by hybridization of amplified products with biotinylated probes using DNA enzyme immunoassay (DEIA), was compared to nested-PCR (N-PCR) on 20 sera from patients with chronic (n = 18) or acute (n = 2) hepatitis. Results obtained by SRT-PCR confirmed by DEIA and by N-PCR identical. All but one of the patients with chronic hepatitis and positive HCV serology as well as the patients with acute hepatitis had detectable HCV RNA in serum; all patients with chronic hepatitis and indeterminate HCV serology and all controls (n = 5) were negative by the two PCR methods. Both SRT-PCR and N-PCR remained positive after 7 x 10(-2) and 5 x 10(-4) dilutions of two HCV RNA-positive sera. The threshold of detection for SRT-PCR was 15 RNA copies per assay, as assessed by testing serial dilutions of an in vitro synthesized 5'-NCR HCV RNA transcript. SRT-PCR confirmed by DEIA for HCV RNA appears to be as sensitive and specific as N-PCR. Furthermore, it is easier to perform, with less of contamination, is less time-consuming, requires fewer enzymes, and it permits semi-quantification of PCR products.

Liver transplantation for acute and chronic viral hepatitis

Hepatotrophic viruses are responsible for a substantial proportion of cases of both end-stage chronic liver disease and of acute liver failure which are treated by liver transplantation. We review here current practice in transplantation for viral-induced liver disease addressing, in particular, the selection of patients for transplantation and the increasingly recognized problem of recurrent disease in liver grafts.

Hepatitis B and D genomes in hepatitis B surface antigen negative patients with chronic hepatitis C

Hepatitis B and hepatitis D viral genomes were tested by nested polymerase chain reaction in the serum and liver of 69 hepatitis B surface antigen (HBsAg) negative, anti-hepatitis C virus (HCV) positive patients (47 with HCV RNA and 22 without HCV RNA). Serum hepatitis B virus (HBV) DNA-was detected in 49% of the patients with HCV-RNA and in 64% of those without HCV-RNA. Furthermore, intrahepatic HBV-DNA was found in four of five (80%) of the biopsies analysed. Delta genome was found in 72% and 73%, respectively, of the anti-HCV positive patients with or without HCV-RNA. In addition, intrahepatic delta virus genome was detected in another four liver biopsies studied. In the group of patients with HCV-RNA, the simultaneous presence of hepatitis B and D genomes was statistically higher in transfused patients than in drug addicts, or in those with an unknown infection route (P < 0.001). These results show a high percentage of B and D genomes in HBsAg negative patients with anti-HCV, irrespective of the presence or absence of the HCV genome. However, the clinical implications of this finding should be examined in future studies.

Evidence of subtype-specific antibodies to antigenic epitopes in the NS5 region of hepatitis C virus in the circulation of patients with chronic hepatitis C

The antigenicity of the NS5 region of type 1 hepatitis C virus (HCV) was investigated by epitope mapping of the region spanning amino acids 2530 to 2723 of the HCV polyprotein. Six antigenic regions were recognized by anti-HCV positive sera from individuals with chronic hepatitis C in a modified enzyme-linked immunosorbent assay with synthetic oligopeptides. Five of these regions demonstrated intra-type 1 sequence variations defining subtype 1a and 1b HCV sequences. The region between amino acids 2623 and 2634 allowed testing of subtype-specific anti-NS5 antibodies; serological reactivity to subtypes 1a and 1b was observed in 27 and 61%, respectively, of 150 cases with chronic hepatitis C. Simultaneous reactivity to subtypes 1a and 1b was found in 23% of the patients. Detection of subtype-specific anti-NS5 antibody correlated in more than 80% of the cases with the HCV genotype (subtypes 1a and 1b) analyzed by PCR amplification of the NS5 sequence. These data provide evidence of the existence of a subtype-specific anti-NS5 response in the circulation of patients with chronic hepatitis C.

Positive and negative hepatitis C virus RNA strands in serum, liver and peripheral blood mononuclear cells in anti-HCV patients: relation with the liver lesion

To investigate the replicative hepatitis C virus status and its relation to liver damage, serum, peripheral blood mononuclear cells and liver-paired samples from 45 untreated hepatitis C virus infected patients (38 with chronic hepatitis, three with minimal changes, and four with normal liver) were studied by nested polymerase chain reaction, using primers from the 5' untranslated region. Positive HCV-RNA strand was detected in serum (69%), peripheral blood mononuclear cells (100%) and liver samples (100%). The presence of negative HCV-RNA strand was confirmed using specificity controls assays and was only detected in liver and peripheral blood mononuclear cells samples, (95% and 82%, respectively). No correlation between the presence of negative HCV-RNA strand in peripheral blood mononuclear cells and positive HCV-RNA strand in serum was found, whereas serum HCV-RNA was not detected in patients without negative HCV-RNA strand in the liver. Both positive and negative HCV-RNA strands were found in liver and peripheral blood mononuclear cells of four patients with normal liver histology, and three with minimal changes. Furthermore, the presence of HCV-RNA in serum did not correlate with the alanine aminotransferase values and the histological activity index. These data confirm the existence of replicative intermediates in the liver, not only from patients with histologically proven chronic hepatitis, but also from those with normal liver, suggesting the existence of hepatitis C virus in true healthy carriers.

The polymerase chain reaction and hepatitis C virus diagnosis

In the absence of tissue culture, electron microscopy or assays for viral antigen, the direct detection of hepatitis C virus (HCV) is by necessity dependent upon nucleic acid hybridisation methods. Of the available methods, amplification of HCV cDNA by polymerase chain reaction (PCR) commends itself by virtue of its extreme sensitivity and its consequent ability to detect the very low levels of HCV-RNA that are present in many clinical samples. In this review the development and evolution of PCR techniques for HCV detection are described and a number of clinical applications are considered in detail. The applications include diagnosis of acute infection during the seronegative window period prior to the appearance of HCV antibodies, and diagnosis of HCV infection in the immunosuppressed. PCR also enables identification of the chronic viraemic carrier state and it permits accurate monitoring of the antiviral effects of drugs such as interferon. Confirmation of the specificity of HCV antibody assays and detection of HCV contamination of blood donations and blood products are other important areas in which PCR techniques have proved invaluable. In addition, PCR-based techniques underlie an increasing number of molecular epidemiological and genotyping studies and they are providing insights into the details of HCV cellular tropism and replication. A number of logistic problems and operational difficulties are also discussed. Despite these limitations it is concluded that PCR will continue to make significant contributions to both clinical practice and to our understanding of the basic biology of HCV infection.

A sensitive PCR method for detecting HCV RNA in plasma pools, blood products, and single donations

Although current manufacturing processes appear to efficiently inactivate hepatitis C virus (HCV), it is possible that contaminated blood products may result from failure of some stage during manufacture or from virus overload of plasma pools used for preparation of products. While antibody screening probably removes the majority of HCV positive donations, some donations which are antibody-negative but HCV positive may be included in pools. The HCV RNA content of plasma pools from paid and voluntary donors was investigated by polymerase chain reaction (PCR). A sensitive PCR method using a single pair of primers from the 5' non-coding region of the HCV genome and a "hot-start" was established and shown to be as sensitive as the more conventional nested PCR (which uses two pairs of primers). The majority of pools from paid donors (prescreening) were HCV RNA positive, while all pools from voluntary donors were both antibody and RNA negative. Intravenous immunoglobulins prepared from contaminated pools were RNA negative despite having high antibody levels, indicating satisfactory clearance of the virus during manufacture. The virus load of the pools was at least a thousand-fold lower than that of single donations, possibly as a result of treatment during the production of the pools or the presence of factors in pools which reduce the sensitivity of some part of the PCR assay. The HCV content of a plasma donation was determined as 3.6 x 10(6) genomes/ml by an end point dilution method. Thus a simple and sensitive PCR assay was established for detecting HCV RNA in plasma pools and blood products.

Hepatitis C: description of a highly sensitive method for clinical detection of viral RNA

To improve the sensitivity of hepatitis C virus RNA (HCV RNA) detection in serum by 'nested' polymerase chain reaction (PCR), primers belonging to 5' non-coding (5'NC) regions were used to compare the classical phenol/chloroform technique by using the proteinase K and silica gel technique with guanidinium thiocyanate. The silica gel techniques was found to be more efficient and sensitive for the extraction and purification of viral RNA from serum samples. The silica gel technique also avoids contact with hazardous volatile chemicals like phenol and chloroform and provides a better protection for viral RNA. Furthermore, the RNA detection sensitivity was greatly improved by modifying the buffer for reverse transcription and PCR. Using silica gel extraction, and the modified buffer, viral RNA was detected in 699 sera from anti-HCV second generation ELISA positive patients. These sera were distributed in second generation RIBA confirmed, indeterminate and non confirmed groups with PCR positive rates of 71.4%, 45.7% and 15.8%, respectively. Two out of 227 ELISA negative patients showed the presence of HCV RNA in serum. An association between the presence of antibodies against a determined viral peptide and viremia was not detected.

A simple single-tube procedure of PCR assay for the detection of hepatitis C virus RNA

We developed a simple single tube procedure using the PCR (polymerase chain reaction) for the detection of hepatitis C virus RNA. The entire reaction from RNA extraction to PCR occurred in one tube; this was made possible by the use of more than 1,000 micrograms/ml of proteinase K for RNA extraction, instead of the acid-guanidinium thiocyanate-phenol-chloroform method. All necessary reagents were added to the tube, and PCR products were not removed from the tube until the end of PCR, although opening of the tube during the procedure could not be avoided. Therefore, cross-contamination which might theoretically take place during transfer of products between tubes never occurred. This method detected about 1 chimpanzee infectious dose of HCV in H strain plasma.

Liver disease patterns in hemodialysis patients with antibodies to hepatitis C virus

The present study correlated histopathology and diagnostic tests in hemodialysis patients with serologic markers for hepatitis C virus (HCV). Hepatitis C virus infection was found in 65 of 163 patients, as assessed by anti-c100-3 (ELISA 1), anti-c22-3, c33C (ELISA 2), and RIBA 2. Several histopathologic patterns were found in 33 liver samples from HCV-positive individuals: cirrhosis (n = 3), chronic active hepatitis (n = 14), chronic persistent hepatitis (n = 2), isolated hemosiderosis (n = 5), reactive hepatitis (n = 6), and others (n = 3). There was a positive correlation between time from the first aminotransferase peak and histologic damage (P = 0.015). However, the severity of liver disease did not correlate with the intensity of RIBA 2 positivity, mean levels or pattern of aminotransferases elevation, or markers of past hepatitis B virus infection. Moreover, aminotransferases were persistently normal in three patients with severe liver disease and were elevated in 10 patients with only mild changes. In 19 biopsied patients, the presence of plasma HCV RNA was examined by the polymerase chain reaction (PCR), which was positive in 15 of the 19 biopsy specimens. The ability of PCR positivity to predict the histologic severity of the disease was insufficient: four patients with minor liver damage had positive PCR and two patients with significant liver damage had negative PCR. No further correlations of PCR positivity were found with the other biochemical or immunologic markers of HCV infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of the polymerase chain reaction in the study of hepatitis C virus infection

Recently, the principal etiological agent of parenterally transmitted non-A, non-B hepatitis was molecularly cloned from the plasma of an experimentally infected chimpanzee and has been named hepatitis C virus. Determination of the complete nucleotide sequence of the hepatitis C virus genome was a crucial step in preparing the way for future study of this medically important human pathogen. Due to the very low concentration of virus in serum, amplification of viral RNA sequences by reverse transcription and polymerase chain reaction is the only practical method currently available for demonstrating viremia in patients with hepatitis C virus infection. This review examines the pivotal role of the polymerase chain reaction in understanding the biology of hepatitis C virus.

Treatment with recombinant alpha-interferon of chronic hepatitis C in anti-HIV-positive patients

A pilot study of chronic hepatitis C treatment was conducted in 14 patients (13 had chronic active hepatitis and 1 had liver cirrhosis). All patients were asymptomatic for the human immunodeficiency virus (HIV) type 1 (mean CD4 count of 584 +/- 283 cells/mm3). Patients received 9 MU rIFN-alpha 2A per day for three months. After this, patients received 9 MU three times weekly for three months, 6 MU for another three months on the same protocol, and finally 3 MU again three times weekly for the last three months. After the first month of ALT treatment in 9 patients (64%) returned to normal; a significant decrease in ALT levels was observed with respect to the pretreatment values (mean of 42 IU/l, range 15-75 vs 152 IU/l, range 69-355; P < 0.01). Of the 9 patients who completed the treatment period, 5 had a complete response, and 4 of these 5 continued with normal ALT values during follow-up (sustained response) while the other patient relapsed within one month after cessation of therapy. The remaining 4 patients were non-responders (including one case with a break-through of the response). HCV-RNA was not detectable in 3 of the 5 responders at the end of therapy while during follow-up viral RNA became undetectable in the other 2 patients. 2/4 non-responder patients had detectable HCV-RNA during follow-up. Liver histology improved in all the patients. No changes were observed in the immunological status or HIV infection.

Detection of hepatitis C virus RNA in serum and peripheral blood mononuclear cells

Hepatitis C virus (HCV) RNA is the most reliable marker of HCV infection. However, because of HCV genome heterogeneity and the procedures used to isolate the viral genome and to perform the amplification steps, results do not accurately reflect the actual rate of HCV infection. In this study, several isolation procedures and sets of primers to perform PCR were compared for the detection of HCV-RNA in serum and peripheral blood mononuclear cells (PBMC) of patients with HCV infection. It was found that the extraction with guanidinium isothiocyanate prior to cDNA synthesis followed by PCR amplification of the 5'-UTR region gave the best results in serum and PBMC. The presence of the viral genome in PBMC is a frequent event during HCV infection and this has important consequences for the understanding of the viral pathogenesis.