Interleukin 28B polymorphisms as predictors of sustained virological response in chronic hepatitis C: systematic review and meta-analysis.

Polymorphism of interleukin 28B gene represents a powerful outcome predictor for interferon-based regimens in hepatitis C virus infection. However, some studies report conflicting results. The predictive value of interleukin 28B genotype over the outcome interferon-α/ribavirin treatment was thoroughly evaluated and compared with virological predictors of response. Literature revision was performed on PubMed. Pooled odds ratios (ORs) were calculated by fixed- or random-effects models. Heterogeneity and publication bias were also assessed. Sixty-two eligible papers including 20 290 patients were retrieved. Both polymorphisms (rs12979860 and rs8099917) were strongly associated with response (OR=4.09 and 4.00, respectively), however, the association was weaker for subjects infected with viral genotypes 2 and 3 (OR=1.52 and 1.49, respectively). Compared with interleukin 28B genotype, the association with response was lower for baseline viremia (OR=2.15) and higher for rapid virological response (OR=13.86). These results provide a critical evaluation of interleukin 28B genotype as a pharmacogenetic predictor in hepatitis C patients.

Differential expression of insulin-like growth factor II mRNA in human primary liver cancers, benign liver tumors, and liver cirrhosis.

We investigated insulin-like growth factor II (IGF-II) mRNA in three groups of human liver samples including primary liver cancers, benign liver tumors and cirrhosis; indeed these pathological conditions would allow us to distinguish between different steps in liver carcinogenesis. A 40- to 100-fold increase in IGF-II mRNA was shown in 9/40 of the liver cancer samples as compared to normal adult liver. RNA blot analysis using both IGF-II cDNA and oligonucleotide probes showed the reexpression of two fetal (6 and 5 kilobases) IGF-II transcripts in primary liver cancers and in some cirrhotic adjacent tissues; these included all the samples with enhanced IGF-II expression. By contrast the adult (5.3 kilobases) IGF-II transcript was identified in most of the benign liver tumors and liver cirrhosis; in addition, in some of these samples, the 5-kilobase fetal transcript was also detected. The increase of IGF-II mRNA in some liver cancers is consistent with an autocrine mechanism conferring a selective growth advantage to tumorous liver cells. Furthermore, these results indicate a differential expression of IGF-II transcripts in nonmalignant hepatocyte proliferation (benign liver tumors and cirrhosis) as compared to liver cancer. Finally this study suggests that, in liver cirrhosis and in some benign liver tumors, premalignant proliferative states might be identified by the presence of IGF-II fetal transcripts.

Hepatitis B virus (HBV) genomic variations in chronic hepatitis.

Using PCR we have examined the sequence of the pre-C/C region of HBV from sera of anti-HBe positive, chronically HBV-infected patients. The large majority of sera tested contained a mixture of heterogeneous pre-C sequences with 1-3 non-randomly located point mutations. Some of the resultant variant viruses are incapable of synthesizing immunogenic proteins and may be involved in viral persistence in chronic carrier states.

Comparison of competitive and non-competitive reverse transcription-polymerase chain reaction (RT-PCR) for the quantification of hepatitis C virus (HCV) RNA.

A competitive reverse transcription (RT)-nested polymerase chain reaction (PCR) assay for HCV RNA was compared with the Roche Amplicor HCV Monitor assay, based on non-competitive, single step RT-PCR. A total of 83 serum samples were tested in parallel by both assays. All samples could be quantified by competitive RT-PCR (cPCR), whereas seven were negative by the non-competitive assay (ncPCR). The HCV RNA titre of the discordant samples assessed by cPCR was significantly lower than that of the remaining 76 (P < 0.001). Absolute HCV RNA titres were higher by cPCR than by ncPCR (P < 0.001), even if the results of the two methods were statistically correlated (P < 0.001). HCV RNA titre tested by cPCR was not significantly different between samples infected with genotype 1 or 2. However, values obtained by ncPCR were higher in samples with genotype 1 (P < 0.001). Furthermore, all seven discordant samples were infected with genotype 2. When both methods were used to measure serial dilutions of standard HCV RNA, we observed a bias to lower measurements with the ncPCR kit. This study shows a good correlation between the results of two PCR-based methods for the quantification HCV RNA. However, the degree of sensitivity and the absolute HCV RNA titre measured may vary according to the assay used.

HCV-RNA detection in ultrasound-guided fine needle biopsies of liver nodules and surrounding tissue.

HCV-RNA was examined in serum and liver tissue obtained from 8 hepatitis B surface antigen (HBsAg) negative patients with liver nodules ranging in size from 2 to 11 cm. Histological examination of ultrasound-guided fine needle biopsies revealed the presence of hepatocellular carcinoma (HCC) in six patients (5 of whom were anti-HCV positive), cholangiocarcinoma in 1 patient (anti-HCV positive) and dysplastic regenerative nodule in 1 patient (anti-HCV negative). The HCCs were surrounded by cirrhosis (3 cases), chronic active hepatitis (CAH) (n = 2) and post hepatitic fibrosis (n = 1), the cholangiocarcinoma by CAH and the regenerative nodule by cirrhotic liver. Total and replicative intermediate HCV-RNA was analyzed by reverse-transcription-nested PCR of the 5'-untranslated region. The five patients with HCC had HCV-RNA in serum, in tumorous and surrounding liver tissues. The viral nucleic acid was also detected in the cirrhotic tissue surrounding the cholangiocarcinoma but not in the tumor. Two out of 5 HCC patients had replicative intermediate RNA (negative strand) in tumorous tissue, 4 in nontumorous tissue and 3 in serum. These results demonstrate that fine needle biopsy can provide sufficient material for both histological examination and HCV-RNA determination and suggest the existence of continuous viral replication during the carcinogenic process.

An immunoassay for specific amplified HCV sequences.

The direct detection of viraemia could improve greatly the efficacy of presently available assays. Due to its sensitivity, the polymerase chain reaction represents the method of choice for direct detection of viral nucleic acid. However, the clinical application of this method is hampered by the requirement of hybridization with radioactively labelled probes. In this study we demonstrate that HCV cDNA, amplified by the polymerase chain reaction from both liver tissues and sera, can be detected specifically by a new non-radioisotopic method, DNA enzyme immunoassay, that is based on an antibody that selectively recognizes double, but not single-stranded DNA. The assay reveals the hybridization events, independently from the DNA sequences, and therefore can be used with any combination of primers and probes. Most importantly, the method has a conventional ELISA format and is compatible with standard facilities of clinical laboratories. The availability of this new approach for revealing amplified sequences may facilitate greatly the use of PCR as the method of choice for early diagnosis of HCV infection.

Relationship between HBV markers and heroin as a cause of liver injury in drug addicts.

Fifty liver biopsies from heroin addicts on methadone maintenance were studied for histological features. The relationship between hepatic damage, HBV markers and the length of drug abuse was analysed. Infiltration was found in 95.6% of hepatitis B surface antigen (HBsAg) positive patients and in 50% of hepatitis B surface antibody (HBsAb) positive and HBV negative patients. The length of drug abuse showed a strong direct correlation with vacuolar degeneration (P less than 0.001) and an inverse correlation with fibrosis (P less than 0.05).

Diagnosis of viral hepatitis with a nonisotopic hybridization assay.

The DNA enzyme immunoassay is an efficient method for the screening of PCR products derived from different hepatitis virus genomes, and allows to bypass both agarose gel electrophoresis and Southern blot hybridization with radioactively labeled probes. A wider application of this method will disclose new perspectives for the introduction of PCR in clinical laboratories.

Role of viral and host factors in HCV persistence: which lesson for therapeutic and preventive strategies?

Several lines of evidence support the view that hepatitis C virus is not directly cytopathic for infected host cells and that the immune response plays a central role in the pathogenesis of liver damage. Innate and adaptive immune responses are induced in most individuals infected with hepatitis C virus but are insufficient to eliminate the virus. The mechanisms responsible for this failure are largely unknown but the kinetics of hepatitis C virus replication relative to the priming of the adaptive responses may exert a profound influence on the balance between virus and host. Immediately after hepatitis C virus infection, the virus replicates efficiently, inducing the production of type I interferons. However, the rapid increase in viral replication seems to be ignored by the adaptive immune response, and after a short interval from exposure, viral load can reach levels comparable to those of patients with established persistent infection. The CD8-mediated response shows functional defects, with impaired production of interferon-gamma, low perforin content, decreased capacity of expansion and lysis of target cells. Late appearance and functional defects of T cells in hepatitis C virus infection might be the result of the rapid increase of the viral load that could create the conditions for exhaustion of the adaptive response or reflect an insufficient function of the innate immune response. This possibility is suggested by in vitro studies showing that hepatitis C virus gene products can interfere with the anti-viral activity of type I interferons and natural killer cells as well as with the maturation of dendritic cells. While T-cell defects are reversed in a minority of infected individuals who succeed in controlling the infection, the T-cell impairment becomes progressively more profound as infection progresses to chronicity. In this situation, therapeutic restoration of adaptive responses may represent a rational strategy to obtain resolution of infection and to complement available therapies. The peculiar kinetics of hepatitis C virus replication and T-cell induction soon after infection may have important implications also for the design of protective vaccines since memory responses may not be able to precede the early peak of viral replication. Therefore, vaccines against hepatitis C virus may be unable to prevent infection but may rather be effective in facilitating a self-limited evolution of infection.

Prevalence and genomic variability of transfusion transmitted virus in Italian cryptogenic chronic liver disease and healthy blood donors.

BACKGROUND: Infection with transfusion transmitted virus, a new member of the Parvoviridae family, has been found in patients both with chronic and fulminant post-transfusion cryptogenic hepatitis. AIM: To evaluate the prevalence and clinical impact of transfusion transmitted virus infection in Italy. PATIENTS AND METHODS: Studies were carried out on 256 patients and control subjects from three centres from Northern, Central and Southern Italy (92 nonA-nonC chronic hepatitis, 10 acute non fulminant cryptogenic hepatitis, 41 hepatitis C virus-related chronic hepatitis and 113 blood donors). Serum transfusion transmitted virus was detected by nested polymerase chain reaction using two overlapping sets of primers. RESULTS: A total of 52 of the 92 patients (54.3%) with chronic cryptogenic liver disease and 17 of the 41 hepatitis C virus chronic hepatitis patients (41.4%) were transfusion transmitted virus-DNA positive. Transfusion transmitted virus co-infection in hepatitis C virus patients was not associated with either a higher severity of liver histology or higher alanine transaminase levels or signs of cholestasis, transfusion transmitted virus was found in 48 out of 113 (42.4%) blood donors. In the majority of samples, transfusion transmitted virus DNA was detected with only one of the two sets of primers used. Genotyping and phylogenetic analysis performed on 21 randomly selected viral isolates showed the presence of both type 1 and type 2 transfusion transmitted virus and allowed identification of two isolates with high homology to genotype 6, described, so far, mostly in Japan. CONCLUSIONS: Transfusion transmitted virus type 1 and 2 infection is common among blood donors and patients with liver disease in Italy. The pathogenic potential of transfusion transmitted virus type 1 and 2 in nonA-nonC hepatitis patients is unlikely but further studies are needed to evaluate the epidemiological and clinical impact of other transfusion transmitted virus subtypes.

Detection of DNA sequences by Southern blot.

This report summarizes the basic methods of DNA extraction, analysis and cloning. Specific technical problems are underlined; moreover, the application of molecular biology techniques to the study of HBV sequences in liver DNA is analyzed.

Distribution of viral genotypes in Italy determined by hepatitis C virus typing by DNA immunoassay.

The distribution of hepatitis C virus (HCV) genotypes in Italy was investigated by PCR amplification of the E1 region and hybridization with type I- and type II-specific nonisotopic probes. Positive PCR results were obtained for 65 of 72 patients (90.3%). Type I was detected in 13 of 72 patients (18%), type II was detected in 39 patients (54.2%), and a mixed type I-type II infection was detected in 7 patients (9.7%). Six amplification products not classified by this method shared a low level of homology with HCV types I and II. HCV type I was significantly associated with human immunodeficiency virus, whereas HCV type II was detected in older subjects who were negative for human immunodeficiency virus markers. These results indicate different epidemiological distributions of HCV types I and II in Italy.

Differential pattern of sequence heterogeneity in the hepatitis C virus E1 and E2/NS1 proteins.

The E1 and E2/NS1 genes, encoding the putative hepatitis C virus envelope proteins, show a high rate of sequence variations. We analyzed the degree and distribution of sequence heterogeneity in serum samples from hepatitis C virus-infected subjects. The mutations in the E1 region were mainly type-specific and the rate of variability was apparently not linked to the clinical phase of the infection. The sequence evolution of the E1 region during interferon treatment was low, regardless of the response to therapy. In contrast, an increased degree of variation, apparently related to the stage of viral replication, was present in E2 region derived from patients undergoing interferon treatment. These results are consistent with the hypothesis that the E2 protein represents a major target of the immune response.

Quantification of hepatitis C virus RNA by competitive amplification of RNA from denatured serum and hybridization on microtiter plates.

The direct detection of hepatitis C virus (HCV) RNA by PCR is widely used to determine the presence of circulating virions. The most relevant limit of this approach is the lack of quantitative information about the viral titer. We report a technique of competitive amplification allowing the estimation of HCV RNA copy number in biological samples. We constructed a standard competitive RNA template containing only two point mutations compared with its wild-type counterpart. The competitor was added in titrated amounts to the target RNA, and the mixture was then reverse transcribed and amplified in the same reaction tube. The relative amounts of target and competitor were determined by differential hybridization on microtiter plates with nonradioactive probes. The evaluation of HCV RNA titer required a single coamplification with the competitor and could be read from a standard curve. Furthermore, this method proved suitable for amplification of HCV RNA directly from serum, thus avoiding the intrinsic variability of the RNA extraction step.

Analysis of the hepatitis B virus genome and immune response in HBsAg, anti-HBs positive chronic hepatitis.

Although the development of antibodies against the hepatitis B virus surface antigen generally leads to the clearance of the infecting virus, anti-HBs reactivity has been reported in patients with chronic hepatitis. In the present study we analyzed the viral genome and the antibody specificity in a series of serum samples collected from a patient who seroconverted to anti-HBs during interferon therapy without clearing HBsAg. The appearance of an anti-HBs response was accompanied by the emergence of a pre-S1 defective viral genome. However, the wild-type adw2 molecular species remained largely dominant during follow up. The patient's antibody response to the surface viral antigens was directed towards the heterologous y subdeterminant and the pre-S1 fragment deleted in the variant hepatitis B virus. These results suggest that the selection of the escape viral mutant does not play a major role in viral persistence.

Quantitative analysis of hepatitis B virus DNA by real-lime amplification.

Diagnostic assays allowing the quantification of hepatitis B virus (HBV) DNA over a wide range of concentrations are important for monitoring patients during antiviral therapy. The aim of this study was to develop a new real-time method for HBV DNA quantification. Primers and probe were selected in a highly conserved region of the HBV S gene, and a plasmid containing the pre-S/S region was used as a standard. Linear quantification of the standard was obtained between 10 and 10(9) copies/reaction, with high correlation between ayw and adw genomes (P<0.001). HBV DNA was detected in serial dilutions of a high-titer serum sample with linear results until 2.4 x 10(3) copies/ml. One hundred eight serum samples positive for hepatitis B surface antigen were tested in both the real-time assay and the Digene Hybrid Capture assay (Digene, USA). HBV DNA could be detected by both assays in 70 samples, with significant correlation of results (P<0.001). Results for 38 samples were below the sensitivity limit of the Digene assay, but they could be quantified by the real time polymerase chain reaction assay. These results show that real-time polymerase chain reaction allows sensitive, rapid and linear quantification of HBV DNA in serum.

Insulin-like growth factor II (IGF-II) mRNA expression during hepatocarcinogenesis in transgenic mice.

Insulin-like growth factor II (IGF-II) mRNA expression is developmentally regulated in liver tissue. We previously observed the reexpression of fetal IGF-II mRNAs in human primary liver cancer and in surrounding cirrhotic tissue. In order to determine the steps of liver cancer progression where the activation of IGF-II fetal mRNAs occurs, we analyzed IGF-II mRNA expression during hepatocarinogenesis in transgenic mice carrying an antithrombin III-SV40 early region hybrid gene. The comparative analysis of mRNAs encoding IGF-II and other differentiation-associated proteins, as well as histological analysis, indicate that the reexpression of fetal IGF-II mRNAs takes place in specific steps of liver cancer progression, both in early pretumorous lesions and in well-differentiated hepatocellular carcinomas.

Evaluation of hepatitis delta virus RNA levels during interferon therapy by analysis of polymerase chain reaction products with a nonradioisotopic hybridization assay.

We developed a nonradioisotopic assay for detection of hepatitis delta virus RNA in serum by combining reverse transcription of RNA, polymerase chain reaction of the resultant complementary DNA and enzyme linked immunoassay detection of the polymerase chain reaction products using a monoclonal antibody specific for double-stranded DNA. This DNA enzyme immunoassay had a limit of detection of cloned hepatitis delta virus RNA similar to that of standard PCR followed by Southern-blot hybridization (approximately 10 copies/sample) and was 10(3) to 10(4) times more sensitive than direct dot-blot hybridization (approximately 10(5) copies/sample). Serial serum samples from six patients with chronic hepatitis delta virus infection undergoing interferon therapy were analyzed by reverse transcription-polymerase chain reaction followed by both standard hybridization and DNA enzyme immunoassay. The results of both methods were comparable, revealing disappearance of hepatitis delta virus RNA after 3 to 6 mo of therapy in three patients, two of whom had also a significant decrease in ALT activity. The DNA enzyme immunoassay test is therefore a potentially useful method for therapeutic monitoring in chronic hepatitis delta virus infection and may contribute to a wider application of polymerase chain reaction in clinical laboratories.