Use of the AST to platelet ratio index in HCV/HIV co-infected patients.

BACKGROUND: The AST to platelet ratio index (APRI), a non-invasive marker of liver fibrosis, has not been well studied in HCV/HIV (hepatitis C virus/human immunodeficiency virus) co-infected patients with advanced HIV. AIM: To compare the accuracy of APRI in HCV/HIV co-infected patients to that in HCV mono-infected patients and to determine the impact of CD4+ T-cell counts on its performance. METHODS: We identified 106 consecutive HCV/HIV co-infected patients and 105 matched HCV mono-infected patients who underwent liver biopsy at Harborview Medical Center over a 5-year period. Performance characteristics were calculated and receiver operating characteristic (ROC) analysis conducted. RESULTS: The area under the ROC curve (AUROC) of APRI for predicting significant fibrosis was similar when comparing those with and without HIV co-infection (0.77 vs. 0.86, P = 0.18), but was lower in HIV co-infected patients with CD4 counts <250 cells/mm³ (0.64 vs. 0.86, P = 0.05). In HIV co-infected patients with CD4 counts ≥250, APRI had higher negative predictive value (93% vs. 88%, P = 0.57), positive predictive value (63% vs. 40%, P = 0.43) and specificity (95% vs. 88%, P = 0.05) than in those with lower CD4 counts. CONCLUSIONS: The AST to platelet ratio index (APRI) performance characteristics appear to be suboptimal in HCV/HIV co-infected patients with CD4 counts <250 and they require further study in this population at increased risk for advanced liver disease.

Laboratory approaches to the diagnosis of hepatitis C virus infection.

Hepatitis C virus (HCV) infection is a major and growing health problem worldwide. Laboratory testing plays an important role in the response to the HCV epidemic. Serologic tests for antibody to HCV are useful for screening purposes. The mainstays of laboratory testing for HCV, however, are the molecular approaches. Qualitative molecular tests are useful for confirmation of positive screening tests. Quantitative molecular tests provide prognostic information regarding the likelihood of response to therapy, and allow the monitoring of treatment efficacy. Similarly, genotyping assays predict response to therapy, and allow rational decisions regarding duration of treatment. The combination of continually improving laboratory testing, together with new drugs targeting distinct molecular determinants that are either essential or important in the viral replication cycle, is likely to lead to dramatic improvements in the management of HCV disease.

Prospective multicenter clinical evaluation of AMPLICOR and COBAS AMPLICOR hepatitis C virus tests.

We conducted a multicenter clinical evaluation of the second versions of the manual AMPLICOR and the semiautomated COBAS AMPLICOR tests for hepatitis C virus (HCV) RNA (Roche Molecular Systems, Inc., Pleasanton, Calif.). The performance characteristics of these HCV RNA tests for diagnosis of active viral infection were determined by comparison to anti-HCV serological test results, alanine aminotransferase levels, and liver biopsy histology results. A total of 878 patients with clinical or biochemical evidence of liver disease were enrolled at four hepatology clinics. A total of 1,089 specimens (901 serum and 188 plasma) were tested with the AMPLICOR test. Sensitivity compared to serology was 93.1% for serum and 90.6% for plasma. The specificity was 97% for serum and 93.1% for plasma. A total of 1,084 specimens (896 serum and 188 plasma) were tested with the COBAS test. Sensitivities for serum and plasma were the same as with the AMPLICOR test. The specificity was 97.8% for serum and 96.6% for plasma. Of the 69 specimens with false-positive and false-negative AMPLICOR test results relative to those of serology, alternative primer set (APS) reverse transcription (RT)-PCR analysis showed that the AMPLICOR test provided the correct result relative to the specimens containing HCV RNA in 64 (92.7%) specimens. Similarly, 66 of 67 (98.5%) false-positive and false-negative COBAS test results were determined to be correct by APS RT-PCR analysis. There were no substantive differences in clinical performances between study sites, patient groups, specimen types, storage conditions (-20 to -80 degrees C versus 2 to 8 degrees C), or anticoagulants (EDTA versus acid citrate dextrose) for either test. Both tests showed >99% reproducibility within runs, within sites, and overall. We conclude that these tests can reliably detect the presence of HCV RNA, as evidence of active infection, in patients with clinical or biochemical evidence of liver disease.

Investigating hepatitis C virus heterogeneity in a high prevalence setting using heteroduplex tracking analysis.

Hepatitis C virus (HCV) infection is very common among chronic hemodialysis patients. In the past, blood transfusion appeared to be the primary risk factor; however evidence of nosocomial HCV transmission in the hemodialysis setting has recently been reported. This report describes a molecular investigation of HCV isolates obtained from a population of 670 patients attending six different Seattle-King County based hemodialysis centers in order to identify potential common source infections. 733 serum specimens were collected from hemodialysis patients in 1992 and 1996, and were tested for HCV antibodies and RNA. Overall, 115 of 670 (17%) patients were positive for HCV RNA, and thus were considered actively infected by HCV. HCV genotype was determined in all cases by restriction fragment length polymorphism, and 93 patients were found to be infected by HCV genotype 1. HCV envelope genes were amplified from the 93 patients with genotype 1 infection, and were studied in further detail by heteroduplex tracking analysis (HTA) using genotype 1a and 1b specific probes derived from the envelope 1 (E1) and envelope 2 (E2) genes. Genetic relatedness between pairs of HCV envelope genes was estimated by calculating the degree of gel shift relative to homoduplex controls. Nucleotide sequencing and phylogenetic analysis was used to confirm genetic relatedness detected by HTA. When HTA was performed using the E1 gene probe, 12 apparently related infections were detected; 10 of 12 (83%) of these infections were confirmed as truly related using the gold standard method of nucleotide sequencing plus phylogenetic analysis. Using an E2 gene probe, 24 infections were apparently related, but only six (25%) were confirmed by sequencing. As a control, 41 envelope genes, which were unrelated by HTA, were sequenced; 0 of 41 (0%) were truly related. In summary, HTA provides a rapid and effective molecular technique for screening HCV genetic relatedness in population-based studies, and should prove valuable in future studies of HCV molecular epidemiology.

Hepatitis C virus nonstructural 5A protein induces interleukin-8, leading to partial inhibition of the interferon-induced antiviral response.

Hepatitis C virus (HCV), a major cause of liver disease worldwide, is frequently resistant to the antiviral alpha interferon (IFN). The HCV nonstructural 5A (NS5A) protein has been implicated in HCV antiviral resistance in many studies. NS5A antagonizes the IFN antiviral response in vitro, and one mechanism is via inhibition of a key IFN-induced enzyme, the double-stranded-RNA-activated protein kinase (PKR). In the present study we determined if NS5A uses other strategies to subvert the IFN system. Expression of full-length NS5A proteins from patients who exhibited a complete response (FL-NS5A-CR) or were nonresponsive (FL-NS5A-NR) to IFN therapy in HeLa cells had no effect on IFN induction of IFN-stimulated gene factor 3 (ISGF-3). Expression of mutant NS5A proteins lacking 110 (NS5A-DeltaN110), 222 (NS5A-DeltaN222), and 334 amino-terminal amino acids and mutants lacking 117 and 230 carboxy-terminal amino acids also had no effect on ISGF-3 induction by IFN. Expression of FL-NS5A-CR and FL-NS5A-NR did not affect IFN-induced STAT-1 tyrosine phosphorylation or upregulation of PKR and major histocompatibility complex class I antigens. However, NS5A expression in human cells induced interleukin 8 (IL-8) mRNA and protein, and this effect correlated with inhibition of the antiviral effects of IFN in an in vitro bioassay. NS5A induced transcription of a reporter gene driven by the IL-8 promoter, and the first 133 bp of the IL-8 promoter made up the minimal domain required for NS5A transactivation. NS5A-DeltaN110 and NS5A-DeltaN222 stimulated the IL-8 promoter to higher levels than did the full-length NS5A protein, and this correlated with increased nuclear localization of the proteins. Additional mutagenesis of the IL-8 promoter suggested that NF-kappaB and AP-1 were important in NS5A-DeltaN222 transactivation in the presence of tumor necrosis factor alpha and that NF-IL-6 was inhibitory to this process. This study suggests that NS5A inhibits the antiviral actions of IFN by at least two mechanisms and provides the first evidence for a biological effect of the transcriptional activity of the NS5A protein. During HCV infection, viral proteins may induce chemokines that contribute to HCV antiviral resistance and pathogenesis.

Elevated levels of interleukin-8 in serum are associated with hepatitis C virus infection and resistance to interferon therapy.

Hepatitis C virus (HCV), a major cause of liver disease worldwide, is frequently resistant to the antiviral alpha interferon (IFN). We have recently found that the HCV NS5A protein induces expression of the proinflammatory chemokine IL-8 to partially inhibit the antiviral actions of IFN in vitro. To extend these observations, in the present study we examined the relationship between levels of IL-8 in serum, HCV infection, and biochemical response to IFN therapy. Levels of IL-8 were significantly elevated in 132 HCV-infected patients compared to levels in 32 normal healthy subjects and were also significantly higher in patients who did not respond to IFN therapy than in patients who did respond to therapy. This study suggests that HCV-induced changes in levels of chemokine and cytokine expression may be involved in HCV antiviral resistance, persistence, and pathogenesis.

Daily interferon therapy for hepatitis C virus infection in liver transplant recipients.

BACKGROUND: Hepatitis C virus infection persists after liver transplantation and causes recurrent liver injury in the majority of patients. Standard dose interferon therapy has been largely unsuccessful for hepatitis C in transplant recipients. METHODS: Twelve patients, at least 7 months posttransplant, with detectable hepatitis C virus RNA in serum and features of hepatitis C on liver biopsy were randomized to interferon-alpha2a, 3 mU daily for 12 months (n=8) or no treatment (n=4). The tolerability of daily interferon dosing in liver transplant recipients was evaluated and effects on hepatitis C virus RNA level, quasispecies evolution, and liver histology were studied. RESULTS: Treated patients had an improvement in histological activity index at the end of therapy relative to controls (median reduction of 2 versus median increase of 1.5) (P=0.04). Four treated patients had a virological response (all bDNA negative, one qualitative polymerase chain reaction negative) compared with none of the untreated patients. Only two of six treated patients tested had evidence of quasispecies diversification on therapy. Seven of eight patients in the treatment group required dose reduction for fatigue and/or depression. They tolerated 1.5 mU of interferon-alpha2a daily. Two treated patients developed graft dysfunction, one of who had histological evidence of rejection and subsequent graft loss. CONCLUSIONS: Low daily doses of interferon were tolerated by liver transplant recipients and provided histological benefit without associated quasispecies diversification in most cases. These findings provide a rationale to study low dose daily or pegylated interferon maintenance therapy for the management of hepatitis C posttransplant.

Diagnosis and monitoring of hepatic injury. I. Performance characteristics of laboratory tests.

PURPOSE: To review information on performance characteristics for tests that are commonly used to identify acute and chronic hepatic injury. DATA SOURCES AND STUDY SELECTION: A MEDLINE search was performed for key words related to hepatic tests, including quality specifications, aminotransferases, alkaline phosphatase, gamma-glutamyltransferase, bilirubin, albumin, ammonia, and viral markers. Abstracts were reviewed, and articles discussing performance of laboratory tests were selected for review. Additional articles were selected from the references. Guideline Preparation and Review: Drafts of the guidelines were posted on the Internet, presented at the AACC Annual Meeting in 1999, and reviewed by experts. Areas requiring further amplification or literature review were identified for further analysis. Specific recommendations were made based on analysis of published data and evaluated for strength of evidence and clinical impact. The drafts were also reviewed by the Practice Guidelines Committee of the American Association for the Study of Liver Diseases and approved by the committee and the Association's Council. RECOMMENDATIONS: Although many specific recommendations are made in the guidelines, some summary recommendations are discussed here. Alanine aminotransferase is the most important test for recognition of acute and chronic hepatic injury. Performance goals should aim for total error of <10% at the upper reference limit to meet clinical needs in monitoring patients with chronic hepatic injury. Laboratories should have age-adjusted reference limits for enzymes in children, and gender-adjusted reference limits for aminotransferases, gamma-glutamyltransferase, and total bilirubin in adults. The international normalized ratio should not be the sole method for reporting results of prothrombin time in liver disease; additional research is needed to determine the reporting mechanism that best correlates with functional impairment. Harmonization is needed for alanine aminotransferase activity, and improved standardization for hepatitis C viral RNA measurements.

Diagnosis and monitoring of hepatic injury. II. Recommendations for use of laboratory tests in screening, diagnosis, and monitoring.

PURPOSE: To review information on the use of laboratory tests in screening, diagnosis, and monitoring of acute and chronic hepatic injury. DATA SOURCES AND STUDY SELECTION: A MEDLINE search was performed for key words related to hepatic diseases, including acute hepatitis, chronic hepatitis, alcoholic hepatitis, cirrhosis, hepatocellular carcinoma, and etiologic causes. Abstracts were reviewed, and articles discussing use of laboratory tests selected for review. Additional articles were selected from the references. Guideline Preparation and Review: Drafts of the guidelines were posted on the Internet, presented at the AACC Annual Meeting in 1999, and reviewed by experts. Areas requiring further amplification or literature review were identified for further analysis. Specific recommendations were made based on analysis of published data and evaluated for strength of evidence and clinical impact. RECOMMENDATIONS: Although many specific recommendations are made in the guidelines, only some summary recommendations are listed here. In acute hepatic injury, prothrombin time and, to a lesser extent, total bilirubin are the best indicators of severity of disease. Although ALT is useful for detecting acute and chronic hepatic injury, it is not related to severity of acute hepatic injury and only weakly related to severity of chronic hepatic injury. Specific tests of viral markers should be the initial differential tests in both acute and chronic hepatic injury; when positive, they are also useful for monitoring recovery from hepatitis B and C.

Prospective characterization of full-length hepatitis C virus NS5A quasispecies during induction and combination antiviral therapy.

The hepatitis C virus (HCV) nonstructural 5A (NS5A) protein has been controversially implicated in the inherent resistance of HCV to interferon (IFN) antiviral therapy in clinical studies. In this study, the relationship between NS5A mutations and selection pressures before and during antiviral therapy and virologic response to therapy were investigated. Full-length NS5A clones were sequenced from 20 HCV genotype 1-infected patients in a prospective, randomized clinical trial of IFN induction (daily) therapy and IFN plus ribavirin combination therapy. Pretreatment NS5A nucleotide and amino acid phylogenies did not correlate with clinical IFN responses and domains involved in NS5A functions in vitro were all well conserved before and during treatment. A consensus IFN sensitivity-determining region (ISDR(237-276)) sequence associated with IFN resistance was not found, although the presence of Ala(245) within the ISDR was associated with nonresponse to treatment in genotype 1a-infected patients (P<0.01). There were more mutations in the 26 amino acids downstream of the ISDR required for PKR binding in pretreatment isolates from responders versus nonresponders in both HCV-1a- and HCV-1b-infected patients (P<0.05). In HCV-1a patients, more amino acid changes were observed in isolates from IFN-sensitive patients (P<0.001), and the mutations appeared to be concentrated in two variable regions in the C terminus of NS5A, that corresponded to the previously described V3 region and a new variable region, 310 to 330. Selection of pretreatment minor V3 quasispecies was observed within the first 2 to 6 weeks of therapy in responders but not nonresponders, whereas the ISDR and PKR binding domains did not change in either patient response group. These data suggest that host-mediated selective pressures act primarily on the C terminus of NS5A and that NS5A can perturb or evade the IFN-induced antiviral response using sequences outside of the putative ISDR. Mechanistic studies are needed to address the role of the C terminus of NS5A in HCV replication and antiviral resistance.

Diagnostic testing for hepatitis C.

Diagnostic tests for hepatitis C virus have improved dramatically over the past decade. Highly accurate tests are now available for screening patients for possible hepatitis C infections and confirming the presence of active viral infection. HCV RNA levels and genotype are very useful in assessing the likelihood of response to antiviral therapy and in guiding the optimum duration of treatment. Absence of detectable HCV RNA using PCR methodology has become the gold standard of successful treatment of patients with chronic hepatitis C. The various tests for hepatitis C are expensive and have their limitations. However, selective use of these assays has greatly improved the care of patients with chronic hepatitis C.

The protein kinase-interacting domain in the hepatitis C virus envelope glycoprotein-2 gene is highly conserved in genotype 1-infected patients treated with interferon.

The hepatitis C virus (HCV) envelope glycoprotein-2 inhibits the interferon (IFN)-induced, double-stranded RNA-activated protein kinase (PKR) via the PKR eukaryotic initiation factor-2alpha phosphorylation homology domain (PePHD). The present study examined the genetic variability of the PePHD in patients receiving IFN therapy. The PePHD from 12 HCV genotype 1 (HCV-1)-infected patients receiving daily IFN therapy was amplified by reverse-transcriptase polymerase chain reaction and analyzed by direct and clonal sequencing. The PePHD was highly conserved in 38 HCV GenBank isolates. There was no difference in pretreatment PePHD sequences isolated from IFN responders versus nonresponders. The major PePHD quasi-species variant did not change after 6 weeks of daily IFN therapy, and in 1 patient the major quasi-species variant did not change during 9 months of observation. Sequencing of 25 pretreatment PePHD clones from 3 patients confirmed that there was extremely low sequence variability surrounding the PePHD. The PePHD is highly conserved in HCV-1-infected IFN responders and nonresponders and does not appear to evolve in response to IFN therapy.

Pretreatment symptoms and dosing regimen predict side-effects of interferon therapy for hepatitis C.

We analysed data from a multicentre interferon (IFN) treatment trial to evaluate symptoms in patients with chronic hepatitis C and to identify factors that might predict development of debilitating IFN side-effects. Two hundred and twenty-two patients (120 US, 102 French) received 3 or 5 million units (MU) of IFN-alpha three times weekly (t.i.w.) for 3 months. Those who had detectable hepatitis C virus (HCV) RNA, as detected by the branched DNA signal amplification (bDNA) assay, at 3 months were intensified to daily therapy, while patients who were bDNA negative continued t.i.w. dosing for the subsequent 3 months of treatment. Symptoms were assessed at baseline, and adverse effects were evaluated at 6 months of therapy. Prior to treatment, the most common symptom that interfered with daily functioning was fatigue, occurring in 25% of patients. The frequency of debilitating fatigue, myalgia, arthralgia, headache, the presence of dry eyes and dry mouth, and use of antidepressant medication increased significantly from baseline to 6 months of IFN therapy (all P < 0.01). In multivariate analysis, the development of a debilitating side-effect at 6 months of treatment was associated with the presence of that symptom prior to therapy in all cases. Symptoms and adverse effects varied by gender and country. Compared with patients maintained on t.i.w. dosing, those who were dose intensified to daily IFN reported more debilitating fatigue, malaise, myalgia, arthralgia, fever, nausea, and headache, and the presence of dry mouth (all P < 0.05). In conclusion, patient characteristics, including pretreatment symptoms, gender and nationality, as well as daily IFN dosing are associated with the development of debilitating adverse effects on IFN therapy.

Hyperbilirubinemia and cholestatic liver injury in hepatitis C-infected liver transplant recipients.

OBJECTIVE: A cholestatic pattern of liver injury has been observed in liver transplant recipients with rapidly progressive hepatitis C. We assessed the frequency and causes of cholestasis in hepatitis C-infected liver transplant patients, and evaluated the clinical and pathological course of those with cholestatic hepatitis C. METHODS: Sixty-nine sequential liver transplant recipients who had detectable hepatitis C viremia were studied retrospectively. Records and diagnostic tests were examined from patients who developed hyperbilirubinemia. RESULTS: Hyperbilirubinemia occurred in 33 of 69 (48%) hepatitis C-infected liver transplant patients. A thorough evaluation including review of clinical and laboratory data, ultrasound with Doppler, cholangiogram, and liver biopsy identified causes of hyperbilirubinemia other than hepatitis C in 26 of 33 patients. Seven patients developed cholestatic hepatitis C characterized by histological features of recurrent hepatitis C and cholestatic liver injury with ballooning of centrilobular hepatocytes, bile ductular proliferation, and canalicular cholestasis, in the absence of other causes of cholestasis. Five progressed rapidly to bridging fibrosis and two died of complications related to liver failure. Four patients with cholestatic hepatitis C showed extended survival after the onset of hyperbilirubinemia. CONCLUSIONS: 1) Hepatitis C is a relatively infrequent cause of cholestasis in liver transplant recipients. 2) The diagnosis of cholestatic hepatitis C requires a multimodality approach to exclude other causes of cholestasis. 3) Cholestatic hepatitis C ranges in severity and is not always associated with rapid development of graft failure, although significant histological abnormalities are frequent.

In situ distribution of hepatitis C virus replicative-intermediate RNA in hepatic tissue and its correlation with liver disease.

Liver failure from chronic hepatitis C is the leading indication for liver transplantation in the United States. However, the pathogenesis of liver injury resulting from chronic hepatitis C virus (HCV) infection is not well understood. To examine the relationship between HCV replication in liver tissue and hepatocellular injury, a strand-specific in situ hybridization procedure was developed. The sensitivity and specificity of digoxigenin-labeled riboprobes were optimized by analyzing Northern blots and cell lines expressing HCV RNAs. For the current study, both genomic (sense) and replicative-intermediate (antisense) HCV RNAs were detected and quantified in 8 of 8 liver tissue specimens from infected patients versus 0 of 11 liver tissue specimens from noninfected controls. The distribution pattern for HCV replicative-intermediate RNA in liver was different from that for HCV genomic RNA. HCV genomic RNA was variably distributed throughout infected livers and was located primarily in the cytoplasm of hepatocytes, with some signal in fibroblasts and/or macrophages in the surrounding fibroconnective tissue. However, HCV replicative-intermediate RNA showed a more focal pattern of distribution and was exclusively localized in the cytoplasm of hepatocytes. There was no significant relationship between the distribution pattern for HCV genomic RNA and any indices of hepatocellular injury. However, a highly significant correlation was observed between the percentage of cells staining positive for replicative-intermediate RNA and the degree of hepatic inflammatory activity (P, < 0.0001). Furthermore, the ratio of cells staining positive for HCV replicative-intermediate versus genomic RNA correlated with the histological severity of liver injury (P, 0. 0065), supporting the hypothesis that active replication of HCV in liver tissue may be a significant determinant of hepatocellular injury.

Relationship between iron concentration and hepatitis C virus RNA level in liver tissue.

Patients with chronic hepatitis C virus (HCV) infection frequently have increased hepatic iron stores. The role of hepatitis C in hepatic iron deposition is unknown. The authors examined whether there is a relation between hepatitis C virus level in liver tissue and hepatic iron concentration. Forty-two paired samples obtained from the liver explants of five patients who underwent transplantation for liver disease due to hepatitis C were studied. Hepatitis C virus levels were measured at multiple sites within each liver by a branched deoxyribonucleic assay. Measurements of hepatic iron concentration were made at adjacent sites by a colorimetric assay. Random effects modeling showed wide intrahepatic variation in hepatic HCV ribonucleic acid (RNA) concentration (variance = 1.2 x 10(4) [mEq/g]2) and hepatic iron concentration (variance = 1.3 x 10(6) [microg/g]2). There was, however, a trend toward an association between the mean HCV level and the mean hepatic iron concentration for each liver (r = 0.30, p = 0.05). In conclusion, HCV level and iron concentration varied within and between cirrhotic livers. Variability in intrahepatic iron concentration was not related to variability in intrahepatic HCV RNA concentration. More studies are needed to determine the cause of variability in hepatic iron and HCV RNA concentration within and between livers in patients with chronic hepatitis C.

Evidence for sequence selection within the non-structural 5A gene of hepatitis C virus type 1b during unsuccessful treatment with interferon-alpha.

Resistance of the hepatitis C virus (HCV) to interferon-alpha (IFN-alpha) therapy in patients with hepatitis C may be genetically controlled by an IFN sensitivity-determining region (ISDR) within the non-structural 5A (NS5A) gene. To assess whether HCV 1b strains carrying a 'resistant' type of ISDR are selected during unsuccessful IFN therapy, we analysed the evolution of the NS5A quasispecies, as detected by the clonal frequency analysis technique, and of the ISDR sequence by nucleotide sequence determination, in 11 patients showing no virological response during two consecutive cycles of IFN-alpha therapy. IFN-resistant patients had a homogeneous ISDR quasispecies with sequences identical to those described as 'resistant-' or 'intermediate-' type ISDR. After retreatment with IFN, further selection towards a homogeneous viral population was observed and 10 out of 11 patients had only one variant of HCV with no or just one single amino acid mutation within the ISDR sequence. Treatment and retreatment with IFN was associated in our non-responder patients with evolution of the ISDR quasispecies towards a rather homogeneous viral population carrying a conserved or minimally mutated ISDR motif, supporting the idea that this motif may be relevant for IFN resistance in HCV 1b-infected individuals.

Molecular epidemiology of hepatitis C infection in U.S. veteran liver transplant recipients: evidence for decreasing relative prevalence of genotype 1B.

OBJECTIVE: The U.S. Veteran population represents a unique patient group to study different HCV genotypes because of geographically diverse exposures. The aim of this study was to characterize the distribution of HCV genotypes in U.S. veterans undergoing liver transplantation (OLT), trace genotypes to modes of acquisition (risk behavior and location), and evaluate the relative prevalence of HCV genotypes according to the time of acquisition. METHODS: Between 10/88 and 12/95, 110 primary OLTs were performed in U.S. Veterans at our center. Forty-nine (45%) patients had detectable HCV-RNA by PCR at the time of OLT. Determination of HCV genotypes was performed by restriction fragment length polymorphism of the 5' noncoding region and classified according to Simmonds et al. RESULTS: Twenty-three of 49 (47%) veterans had 1a, 17 (35%) 1b, two (4%) 2a, three (6%) 2b, two (4%) 3a, two (4%) mixed (1a/2a, 1b/2a). This distribution of HCV genotypes was comparable to the genotypic distribution of a contemporary cohort of nonveteran OLT recipients at the University of Washington. There was a statistically significant association between illicit injection drug use (IDU) and 1a, with 63% of 1a patients having IDU whereas only 14% of 1b patients admitted to IDU (p = 0.03). All patients in whom the mode of acquisition was unknown had genotype 1b (p = 0.04). Intranasal cocaine use was strongly correlated with IDU (p = 0.002). Patients who had tattoos but no history of blood transfusion (BT) or recreational drug use had genotype 1 (2 had 1a, 2 had 1b; p = NS). Twenty-two (45%) patients had serological evidence of prior hepatitis B (HBV) infection. Patients who had genotype 2a, 2b, 3a, or mixed were much more likely to have had HBV (seven of nine, 78%) than patients with genotype 1a or 1b (15 of 40, 37.5%) (p = 0.03). There was no significant correlation between BT, dates, or military branch of service, high risk behavior in Southeast Asia, level of education, ethnicity, and particular genotype(s). Whereas the proportion of 1b accounting for HCV infection in patients with a first exposure before 1968 was 50%, all patients with a first exposure post-1975 were non-1b (p = 0.04), suggesting a change in the epidemiology of HCV in our cohort. CONCLUSIONS: In U.S. Veterans undergoing OLT: 1) 45% had PCR-confirmed HCV infection, 2) 1a was the predominant genotype and was associated with IDU, and 3) a significant decrease in the prevalence of genotype 1b from the pre-Vietnam era to post-1975 suggests a changing epidemiology of HCV genotypes.

Association of multispecific CD4(+) response to hepatitis C and severity of recurrence after liver transplantation.

BACKGROUND & AIMS: After liver transplantation for hepatitis C virus (HCV), reinfection of the allograft invariably occurs. Indirect evidence suggests that the cellular immune response may play a central role. The purpose of this analysis was to determine the correlation between HCV-specific peripheral CD4(+) T-cell responses and the severity of recurrence after liver transplantation. METHODS: Fifty-eight HCV-seropositive patients, including 43 liver transplant recipients with at least 1 year of histological follow-up, were studied. Peripheral blood mononuclear cells (PBMCs) were isolated from fresh heparinized blood and stimulated with either recombinant HCV antigens (core, E2, NS3, NS4, and NS5) or control antigens. RESULTS: Fourteen (40%) of 35 patients with mild or no evidence of histological recurrence within their allografts responded to at least 1 of the HCV antigens. Eleven responded to NS3, 5 to all the nonstructural antigens, and 3 to the HCV core polypeptide alone. In contrast, in the 8 patients with severe HCV recurrence, no proliferation in response to any of the HCV antigens was seen (P = 0. 03) despite responses to the control antigens. CONCLUSIONS: Despite immunosuppression, HCV-specific, major histocompatibility complex class II- restricted CD4(+) T-cell responses are detectable in patients with minimal histological recurrence after liver transplantation. In contrast, PBMCs from patients with severe HCV recurrence, despite being able to proliferate in response to non-HCV antigens, fail to respond to the HCV antigens. These findings suggest that the inability to generate virus-specific T-cell responses plays a contributory role in the pathogenesis of HCV-related graft injury after liver transplantation. It is hoped that further characterization of the immunoregulatory mechanisms related to recurrent HCV will provide the rationale for novel therapeutic strategies and diminish the incidence of inevitable graft loss.

Hepatitis C virus: current understanding and prospects for future therapies.

Hepatitis C virus (HCV) is the leading cause of chronic liver disease worldwide and the leading indication for liver transplantation. The hallmark of the disease is its propensity to evolve into chronicity, probably because viral heterogeneity allows the virus to escape immune-mediated neutralization. Treatment with interferon alpha (IFN-alpha) has been disappointing, but higher and more frequent doses, and combination therapies, including nucleoside analogs, might lead to improved suppression of HCV RNA levels. Molecular analysis of HCV before and during treatment has indicated that high viral RNA levels and the presence of HCV genotype 1 are independent predictors of poor treatment outcome. New antiviral agents in development include inhibitors of HCV replicative enzymes, such as protease, helicase and polymerase, as well as several genetic approaches, such as ribozymes and antisense oligonucleotides. The main hindrance to drug development for hepatitis C is the lack of a small animal model or a productive tissue culture system for assessing drug action.