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.     

Rat as an animal model carrying human hepatitis B virus in hepatocytes

OBJECTIVE: To establish an experimental animal model of rat carrying human hepatitis B virus in the hepatocytes using a simple and reproducible method. MATERIALS AND METHODS: Human serum rich in hepatitis B virus was injected into portal veins and caudalis veins of young male Wistar rats. One and two months after the injection, liver biopsies were done. In situ hybridization and immunohistochemical study of liver specimens were carried out. Sera were also examined for HBV DNA by polymerase chain reaction. RESULTS: All of seven rats in this experiment were HBV DNA and HBV surface antigen (HBsAg) positive in their hepatocytes. Most HBV positive hepatocytes were distributed around the central vein and scattered in the liver lobules, and HBV DNA and HBsAg were located in cytoplasm. HBsAg exists mainly as the forms of diffuses and inclusion body. No hepatocytic damage or inflammation was observed. Neither viremia nor antigenemia was detected. CONCLUSIONS: Our studies showed for the first time that natural human HBV can enter Wistar rat liver cells through intravenous injection efficiently and express for a long period. This animal model can be used in the studies of HBV molecular biology, therapeutic regimens and prophylaxis against HBV. A possible mechanism of HBV entering rat hepatocytes is also proposed.     

Fibrosing cholestatic hepatitis in a transplant recipient with hepatitis B virus precore mutant

A patient with hepatitis B virus (HBV) precore mutant (seropositive for hepatitis B surface antigen [HBsAg], anti-hepatitis B e antigen [HBeAg], and HBV DNA) who underwent orthotopic liver transplantation for end-stage liver disease is described. Sequencing of the HBV precore region of the pretransplant serum sample confirmed the presence of the precore stop-codon mutant (G-->A mutation in codon 1896) only. The patient received HBV immunoglobulin prophylaxis for 6 months but HBV recurred thereafter with a mild hepatitic flare, and he remained seropositive for HBsAg, anti-HBe, and HBV DNA. The initial hepatitic illness resolved in 3 months. The patient remained well for another 16 months before presenting with fibrosing cholestatic hepatitis (FCH). During his entire initial hepatitic flare, quiescent period, and final FCH phase, he remained seropositive for HBsAg, anti-HBe, and HBV DNA. Moreover, sequencing of the serum HBV DNA in final FCH phase showed the presence of the identical HBV precore mutant. Immunohistochemical staining showed extensive expression of HBsAg/pre-S1, pre-S2, and hepatitis B core antigen, but HBeAg was scarcely detectable. This case illustrates that (1) recurrence of HBV precore mutant infection can occur in liver; (2) it can give rise to FCH; and (3) hepatic accumulation of HBeAg is not essential for the development of FCH.     

A histopathological study of alcoholics with chronic HCV infection: comparison with chronic hepatitis C and alcoholic liver disease

To clarify the relationship between hepatitis C virus infection and excessive alcohol intake, we carried out histological examination of the liver in 46 alcoholics with chronic hepatitis C virus infection and compared the findings in 55 patients with chronic hepatitis C, 38 with alcoholic liver disease, and 27 with chronic hepatitis B. The majority of alcoholics with chronic hepatitis C virus infection displayed virus-related histological changes very similar to those in chronic hepatitis C, including frequent lymphoid follicles (34.7%) or aggregates (93.3%) in the portal tracts, mild necroinflammatory change (76.1%) in the parenchyma, and lymphocytosis in sinusoids (83.7%). Liver cell dysplasia and irregular regenerative activity of hepatocytes were rarely observed. The effects of alcohol on the liver were found to be minimal in the majority. These findings could suggest that the hepatic injury in the majority of alcoholics with chronic hepatitis C virus infection in Japan is due to persistent hepatitis C virus infection rather than to alcoholic injury. In addition, our study disclosed that the perivenular fibrosis which is designated as a histological characteristic of alcoholic liver disease is frequently observed in chronic hepatitis C. These similarities suggest that a similar fibrogenesis is present in chronic hepatitis C and alcoholic liver disease.     

A case of syncytial giant cell hepatitis with features of a paramyxoviral infection

Adult syncytial giant cell hepatitis (GCH) is an uncommon and often fulminant form of hepatitis that may be caused by infection with a novel paramyxo-like virus. We present the case of a 69-yr-old man who presented with acute, community-acquired hepatitis and chronic lymphocytic leukemia. A liver biopsy showed the typical findings of panlobular syncytial giant cell hepatitis. Electron microscopic examination demonstrated abundant nucleocapsid-like protein material in the cytoplasm and nuclei of affected hepatocytes. These structures were similar to, but distinct from, those of known paramyxoviridae, suggesting infection with a novel, related virus. In situ hybridization studies with a probe directed against the measles fusion protein gene gave a positive signal with a hepatocyte distribution. No signal was obtained with the measles nucleocapsid protein probe, suggesting that the disease agent was genetically distinct from, but related to, the measles virus. Subsequent liver biopsies were characterized by the gradual disappearance of the giant cell changes and by the concomitant development of cirrhosis. This is a case of adult GCH that resolved spontaneously and led to cirrhosis, thus implicating GCH as a potential cause of "cryptogenic" liver disease. Our findings provide further support for the existence of a distinct, as yet unidentified viral species as a cause of this disease.     

Vertical transmission of hepatitis E virus

Little is known about vertical transmission of hepatitis E virus from infected mothers to their infants. We studied eight babies born to mothers infected with hepatitis E in third trimester. One baby was icteric at birth with elevated transaminases and four babies had anicteric hepatitis. Two babies were born with hypothermia and hypoglycaemia and died within 24 h; one had massive hepatic necrosis. Hepatitis E virus RNA was detected by PCR in cord or birth blood samples of five infants. Six infants had evidence of hepatitis E infection. We conclude that hepatitis E virus is commonly transmitted from infected mothers to their babies with significant perinatal morbidity and mortality.     

Enhanced HBsAb production in pathogenesis of fulminant viral hepatitis type B

The possible importance of humoral immunity in the pathogenesis of fulminant hepatitis was investigated by comparing 17 patients with fulminant hepatitis type B with 20 patients with severe but non-fulminant disease. Hepatitis B surface antigen (HBsAg) was cleared from the serum significantly faster (P less than 0-001) in those with fulminant hepatitis, and in 41% anti-HBsAg (HBsAb) was detectable by radioimmunoassay (RIA) at presentation. In all 11 sera from patients with fulminant hepatitis that were examined by electron microscopy aggregates of HBsAg and HBsAb were seen. In contrast, HBsAb was never detected by RIA in those with non-fulminant hepatitis, and in only one serum specimen (5%) were aggregates seen on electron microscopy. A significant sex difference between fulminant and non-fulminant hepatitis was observed, 65% of patients with fulminant hepatitis but only 15% of patients with non-fulminant hepatitis being women (P less than 0-01). An enhanced production of HBsAb in fulminant hepatitis, by leading to free HBsAb in portal blood, may cause an Arthus reaction in the sinusoids of the liver with ensuing ischaemic necrosis of hepatocytes.     

Intracellular accumulation of incompletely processed transforming growth factor-alpha polypeptides in ground glass hepatocytes of chronic hepatitis B virus infection

BACKGROUND: Transforming growth factor-alpha is an intracellularly processed and secreted polypeptide that induces a proliferative response in epithelial target cells and represents a potential regulatory factor in embryonic development, liver regeneration, and also hepatocarcinogenesis. We have observed focal transforming growth factor-alpha expression in liver tissues with chronic hepatitis B virus infection. METHODS: To further elucidate the nature of this focal transforming growth factor-alpha accumulation we have analyzed overall 23 different liver tissues with chronic hepatitis B virus and hepatitis C virus infection as well as normal liver tissues by immunohistology, ELISA, and Western immunoblot with and without immunoprecipitation. RESULTS: By immunohistology transforming growth factor-alpha polypeptides showed focal subcellular accumulation in ground glass hepatocytes, the histological hallmark of chronic hepatitis B virus infection, in co-localization with HBV-preS1 antigen. By ELISA and Western immunoblot increased tissue concentrations of transforming growth factor-alpha were demonstrated in chronically hepatitis B virus-infected liver tissues with ground glass hepatocytes, especially a 15-kD polypeptide, most likely representing an incompletely processed transforming growth factor-alpha polypeptide. Transforming growth factor-alpha retention in ground glass hepatocytes is not a general unspecific effect, since it was not observed for several other secretory liver proteins. Accumulated transforming growth factor-alpha in ground glass hepatocytes does not co-localize with Epidermal Growth Factor Receptor expression. CONCLUSION: Thus evidence is presented that a principally secreted (viral) polypeptide (HBV-preS1) can interfere with the secretion and processing of a second (cellular) protein (transforming growth factor-alpha). Accumulation of transforming growth factor-alpha may result from alteration of the endoplasmic reticulum due to storage of hepatitis B virus surface antigen particles. No evidence was found for transforming growth factor-alpha in ground glass hepatocytes to intracellularly interact with the Epidermal Growth Factor Receptor.     

GB virus-C/hepatitis G virus infection in an area endemic for viral hepatitis, chronic liver disease, and liver cancer

BACKGROUND & AIMS: GB virus-C/hepatitis G virus (GBV-C/HGV) is a newly identified flavivirus, and little is known about its clinical significance. GBV-C/HGV was investigated in different populations, and its coinfection was investigated in patients with liver disease in Taiwan where hepatitis B and C are endemic. METHODS: Viral RNA was studied in 70 high-risk individuals, 20 patients with chronic non-B, non-C hepatitis, 13 with non-A-E fulminant hepatitis, 100 with asymptomatic hepatitis B surface antigen carriage, 120 with hepatitis B surface antigen-positive chronic liver disease and hepatocellular carcinoma, 100 patients with chronic hepatitis C, and 100 healthy adults. RESULTS: GBV-C/HGV infection was more frequent in high-risk groups (15%-30%) and hepatitis C virus carriers (10%) than in healthy adults (1%) and hepatitis B virus carriers (3.2%). Eighty-three percent of those infected had undergone blood transfusions previously. The prevalence in hepatitis B virus carriers increased with the severity of liver disease, being 1% in asymptomatic carriers and 10% in hepatocellular carcinoma. In chronic hepatitis C, clinical and virological data were comparable between those with and without coinfection. CONCLUSIONS: In Taiwan, GBV-C/HGV infection is common in high-risk groups, and its coinfection seems to not aggravate the course of chronic hepatitis B or C.     

Immune response to HBsAg, HBcAg and e-antigen in patients with acute hepatitis and HBsAg carriers with and without liver diseases

Humoral and/or cell-mediated (CMI) immune responses to HBAg components, human and rabbit liver specific proteins (HLP and RLP) and tuberculin were tested in patients with acute virus B and non-B-hepatitis, asymptomatic HBsAg carriers and HBsAg positive chronic active hepatitis (CAH). Furthermore, the presence of HBsAg, HBcAg and/or "e"-antigen has been studied in patients with sera and/or liver tissue. Asymptomatic HBsAg carriers are characterized by a status of immunological tolerance against HBsAg. HBcAg in liver nuclei could not be detected. All sera were positive for anti-HBc, some had anti "e". - Patients with uneventful acute virus-B-hepatitis developed CMI against HBsAg 4-6 weeks and anti-HBs 4-6 months after onset of the disease. Acute virus hepatitis without detectable HBsAg are defined as non-B-hepatitis by negative humoral and cell-mediated immune reaction against HBsAg 1-12 months after onset of the disease. - Patients with type B chronic active hepatitis are characterized by inadequate CMI against HBsAg without immune elimination of virus and virusantigens. Acute and chronic type-B-hepatitis showed temporary or constant CMI against HLP. These findings suggest an alteration or a carrier function of membrane antigens of virus infected hepatocytes or an induction of new membrane antigens by a virus. The results indicate that recovery from type B-hepatitis is associated with the ability to elicit a specific immune response to HBsAg. Furthermore immune responses to virus, virus antigens and virusinfected hepatocytes seemed to be the pathogenic principle of virus induced acute and chronic liver diseases.     

Detection of hepatitis C virus RNA in the liver by in situ hybridization

To examine HCV infection histologically, we attempted non-radioactive in situ hybridization of HCV-RNA in the liver. We amplified cDNA probe (360 base pairs) by PCR using the primers deduced from the core region of the HCV genome. The probe was labelled with digoxigenin by PCR and used for in situ hybridization on paraformaldehyde-fixed frozen liver sections. The hybrids were visualized immunohistochemically with alkaline-phosphatase-conjugated anti-digoxigenin and alkaline-phosphatase substrates. HCV-RNA-cDNA hybrids were detected in 21 of 24 patients with positive serum HCV markers, whereas there were no positive signals in the liver of 12 cases without HCV infection. The signal intensity of HCV-RNA-cDNA hybrids was abolished after RNase treatment. Various other specificity experiments also verified specific hybridization of HCV-RNA-cDNA. HCV-RNA was visualized in liver cells and most of them were regarded as hepatocytes from their characteristic features. The infected hepatocytes were frequently associated with mononuclear cell infiltration. Hepatocytes positive for HCV-RNA were sometimes binuclear and distributed in various patterns among cases tested. The present in situ hybridization of HCV RNA is highly sensitive and specific and the results suggest the host immune response to HCV-infected cells.     

Measuring food intake in wild animals: primates

Rabbit hemorrhagic disease is a rapidly lethal infection caused by a calicivirus, characterized by acute liver damage and disseminated intravascular coagulation (DIC). Following morphological criteria and using a specific in situ labeling technique, we have found that liver cell death induced upon infection is due to apoptosis, and that programmed cell death is a constant feature in rabbits experimentally infected with RHDV. The process affected mainly hepatocytes, but also macrophages and endothelial cells presented morphologic hallmarks of apoptosis, expressing all these cell types viral antigens as determined by immunohistochemistry. The occurrence of programmed cell death was correlated with the appearance of the RHDV induced pathology in tissues by DNA fragmentation detection in situ. Hepatocyte apoptosis produced extensive parenchymal destruction causing a lethal, acute fulminant hepatitis that is characteristic of RHD. Apoptosis of intravascular monocytes and endothelial cell was observed together with fibrin thrombi in blood vessels. Since apoptotic cells are known sites of enhanced procoagulant activity, apoptosis of these cell populations might constitute a first step in the pathogenesis of DIC and a common pathway to other viral hemorrhagic fevers. In conclusion, apoptosis in RHD may be determinant in the development of the pathogenesis of this disease.     

Virus RNA persists within the retina in coronavirus-induced retinopathy

The murine coronavirus, mouse hepatitis virus (MHV), JHM strain, induces a biphasic retinal disease in adult BALB/c mice. In the early phase, Day 1 to Day 7, a retinal vasculitis is noted which is associated with the presence of viral proteins and infectious virus. In the late phase, Day 10 to Day 140, a retinal degeneration is associated with the absence of viral proteins, infectious virus, and inflammatory cells. The purpose of this study was to determine if viral RNA persists within the retina during the retinal degenerative phase of the disease. BALB/c mice were inoculated by the intravitreal route with 10(4.0) TCID50/5 microliters of virus. The presence of viral RNA was detected by in situ hybridization with a viral cDNA probe and viral proteins were identified by immunocytochemical staining. During the acute phase of the infection, viral RNA was found in the retina, RPE, ciliary body epithelium, and the iris epithelium. During the late phase of the infection, viral RNA was almost exclusively found within the retina and RPE and not in the anterior segment of the eye. Within the retina, viral RNA was detected in the ganglion cell layer, the inner retina, the outer retina, and the RPE cell. Immunocytochemical staining identified viral protein within the retina only from Day 1 to Day 8. This ocular disease was also associated with a persistent systemic infection. Both viral RNA and viral proteins were identified within the liver during the first 8 days. However, only viral RNA was detected in the liver from Day 8 to Day 60. These studies demonstrate that MHV established an acute infection (Day 1-8) where infectious virus and viral proteins were identified. This was followed by a persistent infection within the retina and liver where only viral RNA were detected by in situ hybridization.     

Detection of hepatitis C virus with RNA polymerase chain reaction in fulminant hepatic failure

The role of hepatitis C virus (HCV) infection in fulminant hepatic failure is controversial. The frequency of serum HCV RNA positivity in previously reported patients with fulminant hepatic failure (FHF) of indeterminate cause ranged from 0 to 12% in the United States and Europe and from 43% to 59% in Asia. We assessed serum HCV RNA using polymerase chain reaction (PCR) and oligoprimers from the 5'UTR of the HCV genome in 26 consecutive patients with FHF. Another laboratory independently performed PCR on 21 of the serum samples using different oligoprimers from the 5'UTR and NS3 region of the HCV genome. Serum HCV RNA was detected in two of seven (28%) patients with hepatitis B, 9 of 15 (60%) with an indeterminate cause, and in none with hepatitis A (n = 2) or drug-induced hepatotoxicity (n = 2). HCV RNA PCR results were concordant between both laboratories in 17 of 21 (81%) of samples. In patients with an indeterminate cause, HCV RNA positivity was significantly associated with the transmission risk factor of low socioeconomic status and Hispanic ethnicity. Eighteen patients underwent liver transplantation (LT) and 15 (83%) survived. Among patients with FHF of indeterminate cause, recurrent or acquired HCV infection after transplantation occurred in three of five (60%) and one of four (25%) patients, respectively. Three of four (75%) patients with hepatitis C virus infection post-LT also developed histologic hepatitis. HCV appears to be the causative agent of a substantial number of cases of FHF classified as indeterminate in the Los Angeles area. Differences in patient populations or risk factors may explain the discordant incidences of HCV infection in FHF observed among different programs.