Hepatitis C virus infection among dialysis patients in Tunisia: incidence and molecular evidence for nosocomial transmission

In order to study the incidence of hepatitis C virus (HCV) infection in Tunisian haemodialysis patients and detect its nosocomial transmission, 395 patients were enrolled in a prospective study (November 2001-2003). HCV serological and virological status was determined initially using, respectively a third generation ELISA and an RT-PCR qualitative assay. The genotype of the HCV isolates was determined by sequencing NS5B region. The issue of nosocomial transmission was addressed by sequencing the HVR-1 region of the E2 gene. About 20% of the patients had anti-HCV antibodies and HCV-RNA was detected in 73% of the anti-HCV positive patients. Two cases of de novo HCV infection were identified in two dialysis centers, during virological follow-up of patients susceptible to HCV infection. The incidence of de novo HCV infection was 0.5%. Determining the genotypes in the first center disclosed that all HCV-positive patients were infected with genotype 1b; sequencing of the HVR-1 region of the E2 gene provided strong evidence that the isolate from the newly infected patient and another infected dialysis patient were closely related, confirming nosocomial contamination. The investigation of the second center is pending. Besides, one patient with negative HCV serology had detectable HCV-RNA at the beginning of the study. This case had HCV genotype 1b, two other infected dialysis patients in the same unit had HCV genotypes 4k and 3a; thus precluding nosocomial transmission. Thanks to molecular and phylogenetic methods, one case of nosocomial HCV transmission in haemodialysis was confirmed. Epidemiological investigation suggested nosocomial transmission via the medical and/or nursing staff.     

Antibody to hepatitis C virus second envelope (HCV-E2) glycoprotein: A new marker of HCV infection closely associated with viremia

The second envelope protein (E2) of the hepatitis C virus (HCV) was cloned and expressed in Chinese hamster ovary (CHO) cells. This E2 glycoprotein was purified using ion exchange and lectin chromatography and used to construct an enzyme immunoassay for HCV E2 antibodies. The assay was shown to have good specificity, and detection of E2 antibodies was positively correlated (97.3%) to the presence of HCV RNA in serum and plasma. A high concordance between HCV 2.0 and E2 EIA reactivities was also observed. E2 antibody was the first serological marker to appear in 3/5 HCV seroconversion panels. This work demonstrated that 42.4% of core and 15.4% of NS3 indeterminate specimens also contained antibodies to E2, suggesting that HCV infection had occurred in these individuals. The E2 antibody assay was used to evaluate HCV 2.0 EIA-positive, HCV 3.0 EIA-negative plasma donors with indeterminate reactivity on RIBA HCV 2.0 or MATRIX HCV 1.0. Several HCV 3.0-negative specimens were shown to contain E2 antibodies in addition to an original indeterminate serological marker, primarily core. It is concluded that anti-E2 is a useful marker for determining HCV infection, and that the presence of antibodies to two nonoverlapping viral gene products suggests true HCV exposure. New HCV 3.0 blood screening tests should detect HCV 2.0-positive donors who present with an indeterminate pattern by RIBA or MATRIX and who also carry E2 antibodies. © 1995 Wiley-Liss, Inc.     

丙型肝炎病毒（HCV）E2／NS1相对保守区多肽抗原在检？…

目的 研究（ＨＣＶ）Ｅ２／ＮＳ１相对保守区多肽抗原在检测抗－ＨＣＶ中的意义。方法 利用ＨＣＶＥ２／ＮＳ１基因编码的膜区糖蛋白合成Ｅ２／ＮＳ１相对保守区多肽抗原,建立酶免疫试验（ＥＩＡ）,对９６例ＨＣＶ感染者及４０例正常献血员进行ＨＣＶＥ２／ＮＳ１抗体的检测,同时平行检测ＨＣＶＲＮＡ肝炎为１３．５５％,慢性丙型肝炎为２５．０４％,无症状感染者为２．０８％;正常献血员中发现３例抗ＨＣＶＥ２／ＮＳ１抗体     

A novel antigen detection immunoassay for field diagnosis of hepatitis C virus infection

The limitations of dominant methods-based on the detection of anti-HCV antibodies or HCV viremia currently used for the diagnosis of HCV infection enhance efforts to have a rapid, simple, sensitive, and specific alternative diagnostic approach to detect viral antigens. A highly reactive IgG antibody was raised to HCV-NS4 recombinant antigen. The produced antibody showed no cross-reactivity with the other HCV structural and nonstructural recombinant antigens (C1 + 2, C3 + 4, E2/NS1, NS3, NS5). The well established ELISA technique was adapted to detect the new target HCV-NS4 antigen in serum samples. Extremely high agreement was found between the results of ELISA and qualitative detection of HCV-RNA, using a RT-PCR test as a gold standard for the diagnosis of HCV infection. Based on these encouraging results, a novel enzyme immunoassay; dot-ELISA was developed for rapid (approximately 5 min) and simple qualitative detection of the target HCV antigen in serum. The developed method detected the HCV target antigen in 95% of serum samples from HCV infected individuals, with a specificity of 97% using sera of noninfected individuals in comparison with PCR test. The antigen detection method showed high predictive values of positive (99%) and negative (90%). Moreover, the dot-ELISA could detect the HCV target antigen in sera negative for anti-HCV Abs, but positive for HCV-RNA, and in sera of HCV infected individuals with low viremia, as well as those with high viremia, using quantitative RT-PCR. Accordingly, the developed highly sensitive and specific HCV antigen detection method could be applied for mass screening of HCV infection.     

Antibody responses to hepatitis C envelope proteins in patients with acute or chronic hepatitis C

Antibody responses to the hepatitis C virus (HCV) envelope proteins E1 and E2 were analyzed using two original assays in sera from 86 patients in different stages of disease. A Western blot assay and an immunofluorescence assay (IFA) were developed using envelope proteins produced, respectively, in Escherichia coli and in CV1 cells infected with a recombinant SV40. As a third method, the INNO-LIA HCV Ab III assay including E2 synthetic peptides was used. Of 38 chronically infected patients positive for anti-E2 antibodies by IFA, 26 were positive in the Western blot assay (68%) and 25 in the INNO-LIA test (66%). Thus, the detection of anti-envelope antibodies is highly dependent on the antigen formulation, and a native glycosylated form of the proteins is probably needed for their efficient detection. This study shows that the antibody response to HCV envelope proteins depends on the phase of infection. A few acutely infected patients displayed a response to E1 or E2 (36% by Western blot, 7% by IFA), and these antibodies seem to develop in patients evolving toward chronicity. The high prevalence in chronically infected subjects (62% to E2 by Western blot, 90% by IFA), particularly in subjects with essential mixed cryoglobulinemia (68% and 100%), confirms that the resolution of infection involves more than these antibodies. The antienvelope response in patients treated with interferon was investigated, but no significant relationship was found between antibody level prior to treatment and the evolution of hepatitis. The detection of anti-envelope antibodies, therefore, is not predictive of the response to antiviral therapy. © 1996 Wiley-Liss, Inc.     

Anti-envelope 1 and 2 immune response in chronic hepatitis C patients: effects of hepatitis B virus co-infection and interferon treatment

Antibodies against envelope glycoprotein 1 and 2 (anti-E1/E2) have been suggested to influence HCV replication levels. Hepatitis B virus (HBV) may interfere with hepatitis C virus (HCV) replication. At present there are no data on anti-E1/E2 antibody responses or on the effect of interferon (IFN) treatment in HBV-HCV co-infection. Accordingly, we evaluated serum anti-E1/E2 antibodies in 50 patients (median age, 26.5; males, 30) with chronic hepatitis, 38 with HCV and 12 with HBV-HCV co-infection, who had undergone alpha-IFN treatment. Before starting IFN, the HCV group showed higher HCV-RNA levels (bDNA assay) than the HBV-HCV group (median 3.75 vs. 0.64 x 10(6) Eq/ml, respectively; P < 0.05). Similarly, the anti-E2 levels (EIA assay) were higher in the HCV group than in the HBV-HCV (mean +/- SD, 53.8 +/- 54.58 vs. 24.5 +/- 41.50 U/ml, respectively; P < 0.02), and the prevalence of anti-E2 was also higher in the HCV group (94 vs. 58%, respectively; P < 0.007). No correlation was found between anti-E1/E2 antibodies and the HCV-RNA levels. The prevalence of E1/E2 antibodies was similar in the different HCV genotypes. Higher baseline levels of anti-E2 antibodies and a decrease or disappearance of anti-E2 antibodies during IFN were associated with IFN sustained response in both groups, whereas no reduction in the anti-E1/E2 levels was observed in non-responders. The data show that HBV co-infection influences both HCV replication and the anti-E1/E2 antibody production. High pre-treatment levels of anti-E2 antibodies and their decrease or disappearance during interferon treatment are often associated with HCV clearance in sustained responders, irrespective of the HCV genotype.     

血清中丙型肝炎NS3抗原ELISA检测方法的建立和初步应用

目的 评价血清中丙型肝炎病毒(HCV)游离NS3抗原的酶联免疫吸附(ELISA)检测方法的特异性和灵敏度,初步探讨该方法在临床应用中的意义.方法 对77例正常人血清标本,173例抗-HCV阳性标本和3708例抗-HCV阴性的其他类型肝炎血清标本检测HCV游离NS3抗原;对部分HCV NS3抗原阳性标本进行验证,包括HCV RNA测定、中和试验和免疫斑点试验;对11例患者的25份系列血清标本进行了HCV游离NS3抗原、HCV RNA和HCV抗体的联合检测,并结合临床资料综合分析.结果 3708例抗-HCV阴性的其他类型肝炎血清标本中有48例为HCV NS3抗原阳性,其中3030例单纯乙型肝炎和445例其他类型肝炎血清标本中分别有44例和4例为HCV NS3抗原阳性;173例HCV抗体阳性标本中有42例为HCV NS3抗原阳性;77例正常人血清标本的HCV NS3抗原检测结果均为阴性;15例HCV NS3抗原阳性标本中有9例为HCV RNA阳性;23例HCV NS3抗原阳性标本的中和率和免疫斑点试验的阳性率分别为87.0%和69.6%;25份系列血清标本的检测结果显示其HCV NS3抗原的吸光度值与时间呈负相关,并有2例HCV NS3抗原阳性标本随着血清中HCV NS3抗原的吸光度值下降,其HCV抗体转阳.结论 血清中HCV游离NS3抗原的ELISA检测方法有较好的特异性和敏感度,在发展中国家应用此方法进行HCV感染的早期诊断有一定的临床意义和推广价值.     

A Novel Antigen Detection Immunoassay for Field Diagnosis of Hepatitis C Virus Infection

Abstract

The limitations of dominant methods-based on the detection of anti-HCV antibodies or HCV viremia currently used for the diagnosis of HCV infection enhance efforts to have a rapid, simple, sensitive, and specific alternative diagnostic approach to detect viral antigens. A highly reactive IgG antibody was raised to HCV-NS4 recombinant antigen. The produced antibody showed no cross-reactivity with the other HCV structural and nonstructural recombinant antigens (C1 + 2, C3 + 4, E2/NS1, NS3, NS5). The well established ELISA technique was adapted to detect the new target HCV-NS4 antigen in serum samples. Extremely high agreement was found between the results of ELISA and qualitative detection of HCV-RNA, using a RT-PCR test as a gold standard for the diagnosis of HCV infection. Based on these encouraging results, a novel enzyme immunoassay; dot-ELISA was developed for rapid (?5 min) and simple qualitative detection of the target HCV antigen in serum. The developed method detected the HCV target antigen in 95% of serum samples from HCV infected individuals, with a specificity of 97% using sera of noninfected individuals in comparison with PCR test. The antigen detection method showed high predictive values of positive (99%) and negative (90%). Moreover, the dot-ELISA could detect the HCV target antigen in sera negative for anti-HCV Abs, but positive for HCV-RNA, and in sera of HCV infected individuals with low viremia, as well as those with high viremia, using quantitative RT-PCR. Accordingly, the developed highly sensitive and specific HCV antigen detection method could be applied for mass screening of HCV infection.     

Usefulness of the phage display technology for the identification of a hepatitis C virus NS4A epitope recognized early in the course of the disease

A dodecapeptide phage-displayed library was screened with the mouse monoclonal antibody (mAb) 2E3C2 which competed with human antibodies for the binding to the HCV c100 recombinant protein. Four mimotopes shared a consensus motif with the HCV 1701-1707 sequence corresponding to the carboxyl-terminal domain of the non-structural protein NS4A. However, these mimotopes reacted with 2E3C2 only, whereas the corresponding NS4 epitope defined at the sequence 1698-1709 and displayed on phage was recognized by both 2E3C2 and sera from HCV infected patients. Using the Spot method of multiple peptide synthesis and alanine replacement analysis, the respective reactivities of mAb 2E3C2 and anti-NS4A human antibodies against NS4 were shown to be directed against two slightly different overlapping minimal linear sequences and to involve different critical residues. The phage clone displaying the NS4 epitope was used to study the specific recognition of this epitope by different individual HCV positive sera as well as by two seroconversion panels of sera from HCV infected patients. Compared with the detection by RIBA of the different HCV antigens and c100 particularly, these results indicated that the antibodies directed against the NS4 (1698-1709) epitope were produced early during the course of the disease and decreased later.     

初次及再次感染HCV后不同功能区抗体的研究

１４例初次ＨＣＶ感染者及１１例再次ＨＣＶ感染者系列血清系在无法检测ＨＣＶ时留存的２８９位手术受血者系列血清中筛选获得。系列血清包括受血前、受血后不同时期收集的血清。回顾性地研究其不同功能区抗体出现的动态变化，抗Ｃ与抗ＮＳ３抗体有早期诊断价值。抗ＮＳ３、抗Ｃ、抗ＮＳ５及抗ＮＳ４抗体在ＨＣＶ感染后系列血清中检出率分别为８４．７６％、７９．２７％、７２．５４％和６８．３９％。感染过程中各区抗体可以全部出现、部分出现或单独出现抗Ｃ、抗ＮＳ３及抗ＮＳ５抗体，未发现单独含抗Ｅ、抗ＮＳ１及抗ＮＳ４区抗体的血清。抗Ｅ、抗ＮＳ１及抗ＮＳ４抗体消失较早。研究表明：以ＨＣＶＣ区、ＮＳ３区及ＮＳ５区编码的优势抗原包被的ＥＬＩＳＡ抗体诊断试剂盒将提高ＨＣＶ的诊断。     

Expression of immunoreactive forms of the hepatitis C NS5A protein in E. coli and their use for diagnostic assays

Summary.  In this study different forms of the hepatitis C virus (HCV) NS5A protein, including a nearly full-length, an amino-terminal and a carboxy-terminal truncated form were produced in E. coli as fusion proteins with the MBP or the GST protein. The chimeric proteins were tested for their reactivity with sera from HCV infected patients by immunoblot and ELISA assays. A panel of 110 sera specimens, including 39 HCV-positive sera, 27 sera from patients with non-HCV-associated liver disease and 44 healthy individuals were analyzed for the presence of antibodies to NS5A. Twenty four (61 %) out of the 39 HCV positive sera, showed reactivity against the nearly full length NS5A, 21 (54 %) against the amino-terminal part of NS5A and 20 (51 %) against the carboxy-terminal part of the NS5A protein in immunoblot assays, suggesting that immunoreactive epitopes are present both at the carboxy- and the amino- terminal part of the protein. None of the 71 HCV-negative serum samples showed any reactivity against the NS5A antigens. With the exception of one patient, similar data were obtained with an ELISA assay based on the use of the nearly full-length NS5A antigen. The data indicate that new forms of NS5A may be potentially valuable antigens for the development of serological assays for HCV. Received December 26, 2001; accepted April 15, 2002 Published online July 10, 2002     

Profiles of GBV-C/hepatitis G virus markers in patients coinfected with hepatitis C virus.

GBV-C/Hepatitis G virus (GBV-C/HGV) is a newly discovered viral agent, found widely among healthy blood donors and among individuals at risk of parenterally transmitted infections. GBV-C/HGV is found frequently in coinfection with HCV. A population of 109 HCV positive patients was examined for the presence of GBV-C/HGV RNA and antibodies to E2. Of the 109 patients, 23 (21%) had serum GBV-C/HGV RNA in serum, 39 (36%) had only antibodies to E2 and 8 (7%) were positive for both markers, with an overall prevalence of 64%. Different serologic and virological patterns were observed in GBV-C/HGV exposed patients according to their infection status. Active infection was characterized by positive RT/PCR signal with primers for both the 5'UTR and NS5 genomic regions, viremia levels above 10(4) copies/mL by real time quantitative RT/PCR and absence of detectable anti-E2. In the transition phase between active infection and recovery, GBV-C/HGV RNA was only detectable by RT/PCR using primers from the 5' untranslated region and viremia levels were below 10(4) copies/ml by quantitative PCR, with or without simultaneous presence of anti-E2 antibodies. Resolved infection was characterized by absence of detectable viremia and, in most patients, by the presence of anti-E2.     

Anti-soluble liver antigen (SLA) antibodies in chronic HCV infection

Hepatitis C infection is associated with autoimmune disorders, such as the production of autoantibodies. Anti-LKM1 and anti-LC1, immunomarkers of type 2 autoimmune hepatitis, have been previously associated with a HCV infection. Anti-Soluble-Liver-Antigen autoantibodies (SLA) are specifically associated with type 1 and type 2 autoimmune hepatitis and more closely related to patients who relapse after steroid therapy. The recent molecular cloning of the soluble liver antigen provides the opportunity to develop more specific tests for the detection of antibodies against it. The aim of this work is to characterize anti-soluble-liver autoantibodies in sera from patients chronically infected by HCV. A recombinant cDNA from activated Jurkat cells coding for the full length tRNP(Ser)Sec/SLA antigen was obtained. ELISA, Western Blot and immunoprecipitation tests were developed and used to search for linear and conformational epitopes recognized by anti-SLA antibodies in sera from patients chronically infected by HCV. Anti-soluble liver antigen antibodies were found in sera from 10.4% of HCV-infected patients. The prevalence was significantly increased to 27% when anti-LKM1 was also present. Most anti-SLA reactivity was directed against conformational epitopes on the antigen. The means titers by ELISA were lower than those obtained in type 2 AIH. The result of autoantibody isotyping showed a subclass restriction to IgG1 and also IgG4. This study shows the presence of anti-SLA antibodies in approximately 10% of HCV infected patients. The prevalence of SLA autoantibodies in HCV infected patients increases when LKM1 autoantibodies are also present. The relationship between the prevalence of this characteristic autoimmune hepatitis autoantibody and the implication of an autoimmune phenomenon in the liver injury of patients chronically infected by HCV needs further investigation.     

Determining the source of nosocomial transmission in hemodialysis units in Tunisia by sequencing NS5B and E2 sequences of HCV

Hepatitis C virus infection is a significant problem in hemodialysis units. HCV is very variable genetically with six genotypes. Clinical and epidemiological investigation of a new infection requires the determination of both the genotype and the strain of the HCV involved. A prospective, epidemiologic study of 395 dialysis patients in Tunisia was conducted from November 2001 to November 2003 to identify the source of nosocomial transmission using phylogenetic analysis of NS5b and E2 sequences. Hepatitis C infection was diagnosed by screening for anti-HCV antibodies and HCV RNA in sera using third generation ELISA and a qualitative RT-PCR assay. HCV strains were genotyped by sequencing the NS5b region. The genetic relatedness of the HCV strains was studied by sequencing the NS5b and the HVR-1 regions of the HCV genome. Two de novo cases of HCV infection were detected during the follow-up. One of them has been described previously. The case described in this study occurred in a center in which 12 patients were already infected with HCV strains belonging to genotypes 1b (n = 8) and 1a (n = 4). Phylogenetic analysis of the NS5b region from the HCV strains circulating in this center disclosed four clusters, confirmed by analysis of the HVR-1 region, providing strong evidence for nosocomial infection. Epidemiological data showed that these patients were dialyzed during the same shift and in the same area. Phylogenetic analysis of NS5b sequences is useful for determining the HCV genotype and providing evidence of nosocomial transmission.     

Anti-Soluble Liver Antigen (SLA) Antibodies in Chronic HCV Infection

Hepatitis C infection is associated with autoimmune disorders, such as the production of autoantibodies. Anti-LKM1 and anti-LC1, immunomarkers of type 2 autoimmune hepatitis, have been previously associated with a HCV infection. Anti-Soluble-Liver-Antigen autoantibodies (SLA) are specifically associated with type 1 and type 2 autoimmune hepatitis and more closely related to patients who relapse after steroid therapy. The recent molecular cloning of the soluble liver antigen provides the opportunity to develop more specific tests for the detection of antibodies against it. The aim of this work is to characterize anti-soluble-liver autoantibodies in sera from patients chronically infected by HCV. A recombinant cDNA from activated Jurkat cells coding for the full length tRNP^(Ser)Sec/SLA antigen was obtained. ELISA, Western Blot and immunoprecipitation tests were developed and used to search for linear and conformational epitopes recognized by anti-SLA antibodies in sera from patients chronically infected by HCV. Anti-soluble liver antigen antibodies were found in sera from 10.4% of HCV-infected patients. The prevalence was significantly increased to 27% when anti-LKM1 was also present. Most anti-SLA reactivity was directed against conformational epitopes on the antigen. The means titers by ELISA were lower than those obtained in type 2 AIH. The result of autoantibody isotyping showed a subclass restriction to IgG1 and also IgG4. This study shows the presence of anti-SLA antibodies in approximately 10% of HCV infected patients. The prevalence of SLA autoantibodies in HCV infected patients increases when LKM1 autoantibodies are also present. The relationship between the prevalence of this characteristic autoimmune hepatitis autoantibody and the implication of an autoimmune phenomenon in the liver injury of patients chronically infected by HCV needs further investigation.     

Proteinase 3 and dihydrolipoamide dehydrogenase (E3) are major autoantigens in hepatitis C virus (HCV) infection

Hepatitis C virus (HCV) infection has been found to be strikingly associated with autoimmune phenomena. The aim of the present study was to investigate the presence of various autoantibodies in patients with HCV infection. Anti-neutrophil cytoplamic antibody (ANCA), anti-dihydrolipoamide dehydrogenase (anti-E3), rheumatoid factor (RF), anti-dihydrolipoamide acetyltransferase (anti-E2), anti-SS-A/Ro (60 kD), anti-SS-A/Ro (52 kD), anti-SS-B/La, anti-topoisomerase II (anti-topo II), anti-cardiolipin (aCL), anti-dsDNA, anti-ssDNA, anti-nuclear antibodies (ANA), anti-proteinase 3 (anti-Pr3) and anti-myeloperoxidase (anti-MPO) were determined in sera from 516 patients with HCV infection, 11 with primary biliary cirrhosis (PBC) and 44 healthy controls. Assays employed were indirect immunofluoresence, the particle latex agglutination test, enzyme-linked immunosorbent assay (ELISA) and immunoblotting. ANCA, anti-E3 antibody and RF were positive in 278/516 (55.6%), 276/516 (53.3%) and 288/516 (56%) patients with HCV infection, respectively. Positivity for ANA was present in 15.8%, anti-ssDNA in 15.6%, anti-dsDNA in 8.5%, aCL in 5%, anti-SS-B/La in 4.1%, anti-SS-A/Ro (60 kD) in 3.9%, anti-E2 in 3.3% and anti-SSA/Ro (52 kD) in 1.2%, anti-MPO in 4.8%, anti-Topo II and anti-actinin in 0%. All sera with ANCA showed c-ANCA patterns and contained anti-PR3 specificity. HCV patients with ANCA showed a higher prevalence of skin involvement, anaemia, abnormal liver function and alpha-Fetoprotein (alpha-FP). HCV patients with anti-E3 antibodies showed a higher prevalence of liver cirrhosis, arthritis, abnormal liver function and elevated alpha-FP levels. The prevalence of autoantibodies was not affected by treatment with interferon-alpha (IFN-alpha). In conclusion, autoantibodies are commonly found in patients with HCV infection. There is a high prevalence of anti-E3, ANCA and RF in these patients. Proteinase 3 and E3 are the major target antigens in HCV infection. HCV may be regarded as a possible causative factor in ANCA-related vasculitis.     

丙型肝炎病毒阳性血清体外感染人肝细胞的研究

目的 研究丙型肝炎病毒(HCV)抗体(Ab)阴性,HCV-RNA阳性血清建立体外感染肝细胞模型.方法 HCV Ab阴性,HCV-RNA阳性的窗口期血清与人肝细胞共同培养,用反转录-聚合酶链反应(RT-PCR)、免疫荧光染色、Western blot、共聚焦显微镜和透射电镜等方法检测细胞内HCV核酸复制、蛋白质表达及超微结构改变.结果 细胞与病毒共同培养7～45 d,细胞内和/或培养上清中可间断检出HCV正、负链RNA;细胞浆内有HCV 核心和NS3抗原的表达;细胞超微结构有改变,并于感染后第24天时观察到类似病毒样颗粒.结论 窗口期血清中的HCV能在人肝细胞7701中复制一段时间.     

E2 and NS5: New antigens for detection of hepatitis C virus antibodies

The value of two new hepatitis C virus (HCV) antigens for detection of HCV antibodies was studied. These two recombinant antigens were derived from the nonstructural-5 (NS5) and envelope -2 (E2) region of the HCV genome. In a panel of 33 HCV-RNA positive samples with indeterminate Riba-2 confirmatory test results, 29 samples (88%) showed additional antibody reactivity against E2 and 12 samples (36%) snowed additional reactivity against NS5. Among 39 HCV-RNA negative, Riba-2 indeterminate donor samples, no additional E2 or NS5 reactivity was found in 34 samples (87%); while 5 samples (13%) showed additional reactivity against NS5 and/or E2. E2 reactivity thus resolved the majority of hitherto indeterminate samples. In serial samples from nine posttransfusion hepatitis C patients, NS5 and E2 antibodies did not appear earlier than classical HCV antibodies. However, E2 antibodies eventually appeared in all nine patients. The recombinant E2 might be a candidate antigen for future HCV antibody assays. © 1994 Wiley-Liss, Inc.     

Serum levels of anti-NS4a and anti-NS5a predict treatment response of patients with chronic hepatitis C

In order to understand better the clinical significance and prognostic value of antibody responses to HCV proteins and in search for parameters that may allow the early identification of non-sustained responders to therapy, antibody levels were measured against NS3, NS4a and NS5a at baseline in the serum of 120 patients chronically infected with HCV of genotype 1 that were classified as sustained responders, relapsers, or non-responders to therapy. The capacity of these antibody tests to predict therapy-outcome was evaluated. While no differences were observed in the anti-NS3 responses in these different response groups, anti-NS4a and anti-NS5a antibodies were observed more frequently and at higher titres in sustained responders versus non-responders or non-sustained responders (=non-responders + relapsers). Based on this observation, a combination of test results consisting of 'the absence of NS4a (AA 1687-1718) antibody at baseline and the presence of HCV-RNA exceeding 10(5) IU/ml after 1 week of treatment' was identified which predicts non-sustained response to treatment with 100% certainty. Replacing the HCV-RNA decision limit by a HCV-core antigen level of >15 pg/ml resulted in the same predictive value. The proposed algorithm also holds for patients treated with peg-interferon and ribavirin. In conclusion, in patients with chronic HCV infection, the decision to continue or stop treatment can be made after 1 week of treatment with (peg)-interferon alpha and ribavirin.     

Subcellular localisation of NS3 in HCV-infected hepatocytes.

Hepatitis C virus (HCV) NS3 is a multifunctional protein with both protease and helicase activities and has been shown to interact with host cell proteins. It is shown that NS3 is present in the hepatocytes from patients with chronic HCV infection by using anti-NS3 antisera. NS3 is detectable in approximately 4% of the hepatocytes from these patients. In most infected cells, NS3 is present in the cytoplasm; however, in a minority of HCV-infected cells, both the cytoplasm and the nucleus or the nucleus on its own are positive for NS3. The presence of NS3 in the nuclei of hepatocytes in chronically infected patients indicates that the protein may play a role other than in virus replication, such as in persistence of HCV infection.