Clinical application of hepatitis C virus core protein in early diagnosis of acute hepatitis C

OBJECTIVE: To investigate the prevalence of currently recognised inherited prothrombotic states in a population of children with arterial stroke. METHODS: Children with arterial stroke presenting to a tertiary level paediatric neurology centre between 1990 and 1996 were investigated for inherited prothrombotic states. RESULTS: Sixty seven children with arterial stroke were investigated. Abnormalities were initially identified in 16 patients; however, only eight children (12%) had an inherited prothrombotic state. This was type 1 protein S deficiency in one patient, the factor V Leiden mutation in six, and activated protein C resistance (without the factor V Leiden mutation) in one. The prevalence of the factor V Leiden mutation was not significantly higher in children with arterial stroke (12%) than in a control population of children without thrombosis attending the same institution (5.2%; Fisher's exact test, p=0.19; difference in prevalence between patients and controls (95% confidence interval)=6.8% (-2.78% to 16.8%)). CONCLUSIONS: Currently recognised inherited prothrombotic tendencies were rarely associated with stroke in this group of children, although larger numbers of patients would be needed to confirm this. Age appropriate normal values should be used when interpreting the results of a prothrombotic screen. Prothrombotic abnormalities seen acutely are as often transient as inherited. Longitudinal assessment and family studies are required before low concentrations of an anticoagulant protein found acutely can be attributed to an inherited abnormality.     

Immunoglobulin M antibody response to hepatitis C virus core protein in patients with chronic hepatitis C

We retrospectively assessed the frequency and clinicopathologic and virologic significance of production of immunoglobulin M (IgM) antibody to hepatitis C virus (HCV) core protein in patients with chronic hepatitis C. Sera from 60 patients with chronic hepatitis C were tested for IgM anti-HCVcore (anti-HCc). Twenty of these patients received ribavirin plus interferon-alpha for 24 weeks, and were classified as sustained, transient, or nonresponders on the basis of alanine aminotransferase levels and the presence of HCV RNA at the end of treatment and 24 weeks later. IgM anti-HCc was detected in 21 patients. There was no correlation between the presence of IgM anti-HCc and clinical features such as sex, age, mode of transmission, serum levels of alanine aminotransferase, HCV genotype, serum HCV titer, or histologic findings. Among the patients who received ribavirin plus interferon-alpha, the mean IgM anti-HCc level before therapy was comparable between sustained (n = 10), transient (n = 8), and nonresponders (n = 2). A statistically significant decrease in IgM anti-HCc response during antiviral therapy was observed in the 18 responders who became negative for serum HCV RNA at the end of therapy. These data suggest that IgM anti-HCc is of limited clinical usefulness as a marker of chronic HCV infection. Serial testing for IgM anti-HCc may provide a marker of antiviral response.     

Prevalence of hepatitis C virus (HCV) infection in Mumbai

A study was carried out to determine the prevalence of Hepatitis C virus (HCV) in Mumbai among certain high risk groups such as renal transplant recipients, multitransfused and haemodialysis patients; professional and voluntary blood donors and viral hepatitis cases for comparison. Repeated testing of 602 subjects for antibodies to HCV using a second generation ELISA assay (Abbott, USA) showed an overall prevalence of 16.9%. We found 36.4% of multitransfused patients, 27.8% of renal failure cases and 26.2% of renal transplant recipients to be seropositive. Voluntary blood donors in our series showed a surprisingly high prevalence of 15.9%, and this group needs further investigation. Fifty-six of these sera (of which 45 were anti-HCV positive) were tested for HCV RNA by PCR and 14(31.1%) of the seropositive samples were also HCV RNA positive. The present investigation not only shows a high prevalence of HCV in the study groups but also proves the presence of HCV genomes in a significant proportion.     

Serodiagnosis of chronic hepatitis C in Japan by second-generation recombinant immunoblot assay

The seroprevalence of antibodies to hepatitis C virus (HCV) by a second-generation recombinant immunoblot assay (RIBA-2) was tested using 4 recombinant antigens. The results were correlated with those of C100-3 enzyme-linked immunosorbent assay (ELISA) and with the detection of HCV-RNA sequences by the polymerase chain reaction. Sera were obtained from 27 C100-3 ELISA-positive Japanese patients with chronic non-A, non-B liver disease and from 29 C100-3 ELISA-negative patients. All C100-3 ELISA-positive patients and 19 (66%) out of 29 C100-3 ELISA-negative patients reacted to two or more RIBA-2 antigens (reactive by RIBA-2). Of the remaining 10 C100-3 ELISA-negative patients, one patient reacted to just one antigen (indeterminate by RIBA-2), while 9 reacted to none of the 4 antigens (non-reactive by RIBA-2). Forty-three (93%) of the 46 RIBA-2-reactive patients and the single RIBA-2-indeterminate patient tested positive for HCV-RNA sequences, whereas only one (11%) of the 9 RIBA-2-non-reactive patients tested positive. These findings indicate that HCV infection is more prevalent than expected from the results of C100-3 ELISA, and that RIBA-2 is a more sensitive assay for estimating the presence of HCV infection in chronic liver disease.     

Enhanced specificity of truncated transmembrane protein for serologic confirmation of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 infections by western blot (immunoblot) assay containing recombinant envelope glycoproteins

Immunoassays based on the highly immunogenic transmembrane protein of human T-cell lymphotropic virus type 1 (HTLV-1) (protein 21c) are capable of detecting antibodies in all individuals infected with HTLV-1 and HTLV-2. However, because of antigenic mimicry with other cellular and viral proteins, such assays also have a large proportion of false-positive reactions. We have recently identified an immunodominant epitope, designated GD21-I located within amino acids 361 to 404 of the transmembrane protein, that appears to eliminate such false positivity. This recombinant GD21-I protein was used in conjunction with additional recombinant HTLV type-specific proteins and a whole virus lysate to develop a modified Western blot (immunoblot) assay (HTLV WB 2.4). The sensitivity and specificity of this assay were evaluated with 352 specimens whose infection status was determined by PCR assay for the presence or absence of HTLV-1/2 proviral sequences. All HTLV-1-positive (n = 102) and HTLV-2-positive (n = 107) specimens reacted with GD21-1 in the HTLV WB 2.4 assay, yielding a test sensitivity of 100%. Furthermore, all specimens derived from individuals infected with different viral subtypes of HTLV-1 (Cosmopolitan, Japanese, and Melanesian) and HTLV-2 (IIa0, a3, a4, IIb1, b4, and b5) reacted with GD21-I in the HTLV WB 2.4 assay. More importantly, HTLV WB 2.4 analysis of 81 PCR-negative specimens, all of which reacted to recombinant protein 21e in the presence or absence of p24 and p19 reactivity in the standard WB assay, showed that only two specimens retained reactivity to GD21-I, yielding an improved test specificity for the transmembrane protein of 97.5%. None of 41 specimens with gag reactivity only or 21 HTLV-negative specimens demonstrated reactivity to GD21-I. In an analysis of additional specimens (n = 169) from different geographic areas for which PCR results were not available, a substantial increase in the specificity of GD21-I detection was demonstrated, with no effect on the sensitivity of GD21-I detection among specimens from seropositive donors. Thus, the highly sensitive, GD21-I-based HTLV WB 2.4 assay eliminates the majority of false-positive transmembrane results, thereby increasing the specificity for serologic confirmation of HTLV-1 and HTLV-2 infections.     

Serological diagnosis of hepatitis C virus in patients with liver disease in Saudi Arabia. Evaluation of antibody determination by recombinant immunoblot assays in relation to RNA detection by polymerase chain reaction

Sera from 164 Saudi Arabian patients with non-A, non-B hepatitis liver disease were examined for antibodies to hepatitis C virus (HCV) by second- and third-generation recombinant immunoblot assay (RIBA-2 and RIBA-3) and for HCV RNA by polymerase chain reaction (PCR). By using RIBA-2, 92 (56.1%) were reactive, 64 (39%) were nonreactive, and 8 (4.9%) were indeterminate. By using RIBA-3, 98 (59.7%) were reactive 60 (36.6%) were nonreactive, and 6 (3.7%) were indeterminate. By using PCR, 108 (65.9%) were positive. Of the eight RIBA-2 indeterminate samples, seven became RIBA-3 reactive but PCR-positive, and one became RIBA-3 nonreactive but PCR-negative. Of the six RIBA-3 indeterminate samples, five were RIBA-2 nonreactive but PCR-positive, and one was RIBA-2 reactive but PCR-negative. From our study on Saudi patients, we conclude that RIBA-3 has slightly but not significantly improved the results of anti-HCV antibody detection, and is probably of more value to resolve those indeterminate samples by RIBA-2. Although expensive, PCR remains the most reliable HCV diagnostic method until an HCV antigen detection test is available.     

An alternative for purification of low soluble recombinant hepatitis C virus core protein: preparative two-dimensional electrophoresis

For isolation of low soluble recombinant full-length (amino acids 1-191) core protein of hepatitis C virus (HCV) overexpressed in Escherichia coli, the advantage of combining two electrophoretic techniques, in comparison with chromatographic separation, is demonstrated. The protein extract was first solubilized in agents compatible with electrophoretic separation. Using preparative liquid phase isoelectric focusing (IEF) the protein of interest was first concentrated within a defined acidic pH range. These fractions were then submitted to preparative sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) to isolate the 22 kDa protein. The second-dimensional step allowed the isolation of 2 mg of the purified recombinant HCV core protein (rHCV-C191) from 1.5 g bacterial pellet. This quantity is sufficient to characterize the protein and to perform immunogenicity studies. This procedure of two-dimensional preparative electrophoresis is applicable to a wide range of biological samples and represents an alternative for purification of insoluble proteins.     

Suppression of host immune response by the core protein of hepatitis C virus: possible implications for hepatitis C virus persistence

Hepatitis C virus (HCV) is a major human pathogen causing mild to severe liver disease worldwide. This positive strand RNA virus is remarkably efficient at establishing chronic infections. Although a high rate of genetic variability may facilitate viral escape and persistence in the face of Ag-specific immune responses, HCV may also encode proteins that facilitate evasion of immunological surveillance. To address the latter possibility, we examined the influence of specific HCV gene products on the host immune response to vaccinia virus in a murine model. Various vaccinia/HCV recombinants expressing different regions of the HCV polyprotein were used for i.p. inoculation of BALB/c mice. Surprisingly, a recombinant expressing the N-terminal half of the polyprotein (including the structural proteins, p7, NS2, and a portion of NS3; vHCV-S) led to a dose-dependent increase in mortality. Increased mortality was not observed for a recombinant expressing the majority of the nonstructural region or for a negative control virus expressing the beta-galactosidase protein. Examination of T cell responses in these mice revealed a marked suppression of vaccinia-specific CTL responses and a depressed production of IFN-gamma and IL-2. By using a series of vaccinia/HCV recombinants, we found that the HCV core protein was sufficient for immunosuppression, prolonged viremia, and increased mortality. These results suggest that the HCV core protein plays an important role in the establishment and maintenance of HCV infection by suppressing host immune responses, in particular the generation of virus-specific CTLs.     

Hepatitis in used syringes: the limits of sensitivity of techniques to detect hepatitis B virus (HBV) DNA, hepatitis C virus (HCV) RNA, and antibodies to HBV core and HCV antigens

Hepatitis virus infections are common among injecting drug users. Syringes containing hepatitis B virus (HBV) DNA and hepatitis C virus (HCV) RNA were identified by polymerase chain reaction (PCR); syringes containing antibodies to HBV core antigen and HCV were identified by EIA. Syringe use was simulated to determine the sensitivity of these assays. The mean limits for PCR were 0.082 microliter of blood for HBV and 0.185 microliter for HCV; the mean limits for EIA were 0.185 microliter for HBV and 0.023 microliter for HCV. HBV PCR testing of 681 syringes returned to the needle exchange program in New Haven, Connecticut, revealed a decline from 7.8% HBV-positive at the program's outset to 2.6%. HCV antibodies were found in 12.1% of 207 syringes tested. Syringe testing can help estimate the prevalence and incidence of hepatitis virus infections when standard seroepidemiologic analyses cannot be applied.     

Reproducibility of hepatitis C virus antibody detection with various confirmatory assays

Angiostrongylus costaricensis (classified under the more specific genus Parastrongylus by different authors) is a filiform intestinal nematode endemic to Central and South America, which afflicts primarily the pediatric population 1 to 13 years of age. Only three cases of adult infections have been previously documented outside the endemic region. To our knowledge, we report the first such case in the western United States, as well as the oldest patient yet recorded. Our patient is a 73-year-old woman living in Los Angeles who presented with an acute abdomen 4 weeks following a 5-month visit to El Salvador. Examination of the gross ileum removed at exploratory laparotomy revealed a perforation associated with a segmentally thickened intestinal wall. Microscopic examination showed eosinophilic ileitis, arterial lumens containing nematodes morphologically consistent with A costaricensis, eggs in the submucosa, and arteriolitis with thrombosis.     

Detection of immunoglobulin M antibodies to glycoprotein G-2 by western blot (immunoblot) for diagnosis of initial herpes simplex virus type 2 genital infections

Western blots (immunoblots) for the detection of immunoglobulin M (IgM) antibodies specific for herpes simplex virus type 1 (HSV-1) and HSV-2 in patients' sera were developed. The locations of the type-specific glycoprotein G (gpG-2) of HSV-2 (92- and 140-kDa forms) and glycoprotein C of HSV-1 (gpC-1), which carries mostly type-specific antigenic epitopes, were checked with specific monoclonal antibodies. Western blot assays for IgM antibody to gpC-1 or gpG-2 were performed after depletion of IgG by precipitation with anti-human IgG. In patients with primary HSV-2 genital infections, seroconversion of IgM and IgG antibodies to both the 92- and 140-kDa forms of gpG-2 was observed, although both antibodies appeared in convalescent-phase serum after the first week. IgM and IgG antibodies to low-molecular-size polypeptides (40 to 65 kDa) were the first antibodies observed in patients with primary infection, but these antibodies were cross-reactive with HSV-1 and HSV-2. However, in patients with recurrent HSV-2 infections, IgG antibodies to both forms of gpG-2 and the low-molecular-size polypeptides were found no matter how early after onset the patient was bled, and IgM to gpG-2 did not appear. In patients with nonprimary initial genital HSV-2 infections, IgG antibody to HSV-1 was demonstrated in the first serum specimen, and HSV-2-specific IgM was found in 39% of the serum specimens. Hence, the Western blot assay can be used to test for IgM antibody to gpG-2, allowing for the retrospective diagnosis of inital HSV-2 infections and its use as a supplementary test to the gpG-2 IgG enzyme-linked immunosorbent assays developed elsewhere. In contrast, IgM antibody to gpG-2 is not usually detected in patients with recurrent HSV-2 infections.     

Usefulness of hepatitis C virus RNA counts by second generation HCV bDNA-probe in chronic hepatitis C based on the HCV genotype

BACKGROUND AND OBJECTIVES: Piriformis syndrome causing sciatica is sometimes refractory to conventional treatments including physical therapy, piriformis injections, and even caudal epidural steroid injections. Surgical release of the piriformis muscle has been described for difficult cases of piriformis syndrome, but is occasionally accompanied by morbidity. Another approach to treating piriformis syndrome is presented. METHODS: A perisciatic injection of steroid using simple landmarks and utilizing a nerve stimulator to locate and inject near the sciatic nerve and into the piriformis muscle is described. RESULTS: Six patients that did not respond to conventional treatments, but did respond to perisciatic steroid injections are presented. CT scan, in one of the patients, confirmed correct needle placement when this technique and landmarks were used. CONCLUSION: Patients with piriformis syndrome who were refractory to conventional treatments but responded to perisciatic injections of steroid are presented.     

Supplementary anti-hepatitis C virus (HCV) testing with 2nd and 3rd generation recombinant immunoblot assay and matrix applied to enzyme immunoassay positive sera and comparison with HCV-RNA detection

Following the same general principles of its two predecessors in 1973 and 1986, the 1996 National Roadside Survey of weekend, nighttime drivers in the 48 contiguous states interviewed and breath tested over 6000 noncommercial four-wheel vehicle operators between September 6 and November 9, 1996. Results indicated that the total number of drinking drivers fell by about one-third between 1986 and 1996; however, there was no significant change in the number of drivers at blood alcohol concentrations (BACs) at or above 0.05. Compared to 1973, the proportion of women drivers on the roads during weekend nights has increased significantly. Moreover, relative to males, the proportion of female drivers who have been drinking has increased over the last decade. The number of drivers under the age of 21 with a BAC at or above 0.10 decreased significantly from 1986 to 1996.     

Different susceptibilities of genetic variants of hepatitis C virus (HCV) to interferon (IFN)

Genetic variants of HCV may have different degrees of resistance to IFN and may therefore influence the outcome of IFN therapy. However, selection of HCV variants by IFN has not been investigated in detail. In this paper, heteroduplex analysis was used to monitor major changes of HCV populations in 4 chronically infected patients under IFN therapy. We found that a major variant of the HCV 5' non-coding region (5' NCR) emerged in a responder. In other patients although no new variant of the 5' NCR was identified, significant changes occurred within the core and E1 region of the HCV genome. Disappearance and emergence of HCV variants may reflect their different susceptibilities to IFN. Our results indicate that responses of HCV populations to IFN are complex and need to be characterized by analysis of multiple HCV genome regions.     

Structure of replicating hepatitis C virus (HCV) quasispecies in the liver may not be reflected by analysis of circulating HCV virions

We have analyzed the population of hepatitis C virus (HCV) sequences in paired liver and serum samples from four patients with chronic hepatitis C. Sequences from three different biopsy specimens from a liver explant from one patient were compared with each other and with the circulating sequences. Our results demonstrate that the circulating quasispecies does not necessarily reflect the viral population replicating in the liver and that this is not due to a macroscopic anatomic compartmentalization of HCV replication. This finding has important implications for the pathogenesis and natural history of chronic HCV infection.     

Characterization of three novel monoclonal antibodies against hepatitis C virus core protein

Three novel monoclonal antibodies (MAbs) were established against a recombinant hepatitis C virus (HCV) core protein derived from cloned genotype 1b HCV cDNA. MAbs C7-50 and C8-59 recognize a conserved linear epitope represented by amino acid residues 21 to 40 of the nucleocapsid protein. MAb C8-48 is directed against a strain-specific conformational epitope located within the first 82 amino acids. A sensitive two-site MAb-based immunoradiometric assay was established using antibodies directed against distinct epitopes on the nucleocapsid protein. Processed 21 kDa core protein was detected by immunoblotting in human hepatocellular carcinoma cell lines and primary adult rat hepatocytes transfected with a cytomegalovirus promoter-driven expression construct. Immunofluorescence microscopy studies revealed a granular and vesicular cytoplasmic staining pattern. MAb C7-50 was used successfully to detect HCV core antigen in chronically infected chimpanzee liver tissue. These MAbs represent important reagents for the study of HCV biology and for the development of immunodiagnostic assays.     

The prevalence of hepatitis C virus (HCV) in infants and children after liver transplantation

Hepatitis C virus (HCV) is an important cause of liver injury following liver transplantation in adults. We hypothesized that the prevalence of HCV infection in children following liver transplantation would be lower than the prevalence in adults after liver transplantation because HCV-related liver disease leading to liver transplantation in children is low and children require less blood products than adults during transplantation. We therefore performed a cross-sectional study to determine the prevalence of HCV infection in children who had undergone liver transplantation. Serum samples were obtained from 62 of 65 (95.4%) consecutive patients surviving for more than six months after transplantation. Using a second-generation enzyme-linked, immunosorbent assay (ELISA-2) and a second-generation recombinant immunoblot assay (RIBA-II), antibodies to HCV were detected in 5.1% (3 of 59) of the subjects. Using a single-step, polymerase chain reaction (PCR), HCV RNA was detected in 6.2% (4 of 62). All HCV-positive children had undergone liver transplantation before the initiation of routine screening for HCV in blood donors; overall 30 patients were transplanted prior to routine screening of blood products for HCV. The prevalence of HCV in infants and children after liver transplantation in our study is substantially less than the rates reported in adults. This difference may be due, in part, to the lower volume of blood product exposure and to the fact that children, as opposed to adults, rarely have chronic HCV infection as a cause of end-stage liver disease.