Hepatitis C viremia in patients with hepatitis C virus infection

Hepatitis C virus infection in Egyptian children: single centre experience

The outcome of hepatitis C virus (HCV) infection acquired in childhood is uncertain because of the diversity of the epidemiological and clinical features of infection and disease. The aim of this study was to determine the outcome of HCV infection in 105 Egyptian children who tested positive for HCV antibody (anti-HCV). The data of 105 anti-HCV-positive children presenting to the Pediatric Hepatology Unit, Cairo University Children's Hospital, between 1995 and 2002, were retrospectively analysed for risk factors. Seventy-four children with available polymerase chain reaction results were further analysed clinically, serologically and histologically. The age range was 1.3-22 years, with a mean of 11.2 +/- 4.9 years. History of blood transfusion was found in 81 children (77%). HCV RNA was detected in 58.1% of 74 children. Persistently elevated alanine aminotransferase (ALT) levels were present in 40 patients (54.1%). Hepatitis B virus markers (HBsAg and/or anti-HBc) were detected in 18 patients (24.3%). Twenty-six of the 43 HCV RNA-positive children underwent a diagnostic liver biopsy that showed chronic hepatitis in 19 patients (73.1%), cirrhosis in one case only (3.8%), and normal biopsy findings in seven children (26.9%). Blood transfusion remains a major risk of HCV transmission among Egyptian children. HCV infection is not always benign in the childhood period. ALT levels remain elevated in half of the children and histological abnormalities are detected in three quarters of HCV RNA-positive cases.

The relationship between virological characteristics of hepatitis C virus (HCV) and reactivity to the regional specific proteins of HCV

BACKGROUND

Although the polyproteins of hepatitis C virus(HCV) are processed and formed in nearly equimolar amounts, individual functional proteins have a discrepancy in their time of appearance following HCV infection and eliciting immune response. This study was conducted to compare the reactivity toward regional specific HCV protein in relation to virological characteristics, including HCV genotype and HCV replication.

METHODS

Sera from forty-five patients with chronic HCV infection were analyzed through the experiments of the recombinant immunoblot assay(RIBA-2), HCV genotyping and HCV RNA quantitation.

RESULTS

The frequencies of seropositivity to C22-3, C33C, C100-3 and 5-1-1 proteins were 91.1%, 91.1%, 64.4% and 53.3%, respectively, of all the patients, and thus the antibodies to C22-3 and C33C proteins were found more frequently (p < 0.05). The antibody responses between core or NS3 proteins and NS4 proteins showed more discrepancy in the HCC group than that in the CH group, implying a possibility of oncogenic potential of core or NS3 gene in hepatocarcinogenesis. The detection rate of antibodies to C22-3 and C33C, in accordance with serum HCV RNA levels, was significantly higher in highly viremic patients than that in low viremic patients (p < 0.05). Antibodies to C22-3, C33C, C100-3 and 5-1-1 were also found more frequently in patients with HCV genotype 1b, compared to those with HCV genotype 2a (p < 0.05).

CONCLUSION

These results suggest that antibody detection of HCV may depend on the virological characteristics of HCV, the levels of HCV replication and HCV genotype and, therefore, HCV RNA detection using RT-PCR technique is essential for confirmatory diagnosis for HCV infection. Furthermore, the HCV core or NS3 Protein may play important role in hepatocarcinogenesis.

A case-control study of the factors associated with spontaneous resolution of hepatitis C viremia

OBJECTIVE

Infection with the hepatitis C virus (HCV) becomes chronic in 85% of the infected individuals. We studied risk factors that may predict clearance of HCV.

METHODS

A case-control study compared the association between risk factors and viral clearance. Viral clearance was defined as presence of a positive HCV antibody test plus negative HCV test by polymerase chain reaction (PCR). Forty-four cases and 214 controls with persistent viremia were identified in a database of patients evaluated at the Gastroenterology Clinic of the University of New Mexico.

RESULTS

Of all 258 HCV-antibody-positive patients, 17% had a negative test by PCR. The multivariate logistic regression revealed that a history of parenteral exposure and a long time interval since the most recent exposure were both associated with an increased likelihood of persistent viremia, whereas subjects who had been monogamous for longer time periods were more likely to have cleared HCV from their serum. A low serum level of ferritin also conferred protection against persistent viremia. Case and control subjects did not differ with respect to their demographic characteristics, occurrence of comorbid disease, previous medical history, occurrence of sexually transmitted diseases, blood group, and risky health or sexual practices.

CONCLUSIONS

These data suggest that route of exposure and time when exposure occurred are important in the development of persistent HCV infection.

Limited humoral immunity in hepatitis C virus infection

BACKGROUND & AIMS

The extremely high rate of chronicity to hepatitis C virus (HVC) infection suggests an inefficient immune response. The humoral immune response to HCV was evaluated in 60 patients with chronic HCV infection and in 12 patients acutely infected with HCV.

METHODS

A number of recombinant HCV antigens including the core, envelope 2 (E2), nonstructural (NS) 3, NS4, and NS5 proteins, and NS4a and E2-HVR-1 peptides were used in enzyme-linked immunoassays.

RESULTS

Immunoglobulin (Ig) G antibody responses to these viral antigens, except for the HCV core, were highly restricted to the IgG1 isotype. The prevalence of antibodies of the IgG1 isotype specific for the HCV core, E2, E2-HVR1, NS3 (helicase domain), NS4, and NS5 antigens was 97%, 98%, 28%, 88%, 33%, and 68%, respectively. Antibodies of the IgG3 isotype specific for E2, E2-HVR-1, NS3, NS4, and NS5 were detected in a minority of serum samples. The IgG2 and IgG4 isotypes were rarely if ever detected. Furthermore, antibody responses to HCV viral antigens were of relatively low titer and, with the exception of anti-HCV core, were delayed in appearance until the chronic phase of infection.

CONCLUSIONS

The IgG1 restriction, low titer, and delayed appearance of antibody responses elicited during HCV infection suggest that the immunogenicity of HCV proteins is limited in the context of natural infection. Inasmuch as recombinant HCV viral antigens perform as relatively normal immunogens in small animals, we suggest that the defective humoral immune responses during HCV infection may be attributable to an "immune avoidance" strategy.

Hepatitis C

Hepatitis C virus (HCV) infection afflicts millions of people in the United States and worldwide. We examine the epidemiology of HCV infection, the molecular biology of the virus, the pathophysiology of infection, the clinical diagnosis and manifestations of infection, and the treatment of HCV infection.

Significance of IgM anti-HCV core level in chronic hepatitis C

AIM

To investigate the significance of IgM antibody to hepatitis C virus (HCV) core antigen (IgM anti-HCV core) in chronic hepatitis C.

METHODS

In a group of 112 patients with histologically proven chronic hepatitis C positive for HCV RNA, IgM anti-HCV core level was studied by a sensitive semi-quantitative enzyme immunoassay. Quantitation of serum HCV RNA was done by a second generation bDNA assay and determination of HCV genotype by RT-PCR and reverse hybridization.

RESULTS

IgM anti-HCV core was detected in 72 (64.3%) of the 112 patients. ALT levels were significantly higher in IgM anti-HCV core positive than negative patients. No other significant difference was observed in any of the patients' characteristics between IgM anti-HCV core positive and negative groups. On the contrary, IgM anti-HCV core level was found to be significantly higher in females than in males, in patients with moderate or severe chronic hepatitis, in patients with high HCV RNA levels and in patients infected with HCV genotype 1b. Moreover, IgM anti-HCV core level was significantly correlated with age and ALT level. Multiple regression analysis showed that IgM anti-HCV core level was significantly related only to the HCV genotype (p=0.001), histological grade (p=0.017) and ALT level (p=0.038).

CONCLUSIONS

Our data support the hypothesis that IgM anti-HCV core level is associated mainly with HCV genotype and secondly with liver disease necroinflammatory activity. These associations may have implications in the pathogenesis of chronic hepatitis C.

Viral replication in patients with concomitant hepatitis B and C virus infections

The aim of this study was to assess the implications of dual infection with hepatitis B virus (HBV) and hepatitis C virus (HCV). The HBV and HCV status in 100 patients with chronic hepatitis was analysed. HBV DNA was studied using liquid hybridization and the polymerase chain reaction (PCR). HCV viremia was measured using qualitative and quantitative PCR. The HCV genotype was determined by PCR. Patients were divided into three groups according to their HCV-RNA and HBsAg status: group I consisted of 40 patients with chronic hepatitis caused by HBV; group II, 40 patients with chronic hepatitis caused by HCV; and group III, 20 patients infected with both viruses. The HBV-DNA level was higher in group I than in group III (66.4 vs. 11.5 pg/ml; p < 0.05). Quantification of HCV viremia revealed mean values of 36.9 copies x 10(5)/ml in group II and 5.5 copies/ml x 10(5) in group III (p < 0.05). The mean aminotransferase level and histological activity were higher in group III. HCV genotype lb was the predominant type. The data suggest that there is reciprocal inhibition of viral replication in patients with dual HBV and HCV infection. Liver disease appears to be more severe in patients with chronic hepatitis B and C.

Correlation between serum HCV RNA and aminotransferase levels in patients with chronic HCV infection

Cross-sectional studies on the correlation between serum hepatitis C virus (HCV) RNA and alanine aminotransferase (ALT) levels in patients with chronic hepatitis C have yielded conflicting results. We conducted a longitudinal study to examine the correlation between HCV viremia and serum ALT levels in individual patients over time. Serial samples (mean 9) from 25 patients with chronic HCV infection, including interferon-treated and untreated immunocompetent and immunosuppressed patients, collected over a period of 1-4.8 years (mean 2.6 years) were tested for HCV RNA and ALT levels using a highly reproducible quantitative (bDNA) assay. A significant correlation was found between serum HCV RNA and ALT levels in the patients who received IFN therapy, but no correlation was observed in the untreated patients. Among the untreated patients, the immunosuppressed patients had significantly higher HCV RNA levels (39 +/- 4 vs 3.6 +/- 8 Meq/ml, P < 0.0001) but significantly lower ALT (56 +/- 11 vs 97 +/- 12 units/liter, P = 0.03) levels when compared to the immunocompetent ones. In summary, we found no correlation between serum HCV RNA and ALT levels in chronic hepatitis C patients who are not receiving interferon therapy. Immunosuppression results in higher HCV RNA but lower ALT levels.

Effect of human immunodeficiency virus infection on hepatitis C virus infection in hemophiliacs

Chronic liver disease due to hepatitis C virus (HCV) infection is a major problem in hemophiliacs. Recent reports suggested that hemophiliacs coinfected with hepatitis C virus and human immunodeficiency virus (HIV) have an increased incidence of liver failure but the mechanism of accelerated liver injury is not clear. We tested plasma from 100 hemophiliacs for anti-HCV by second generation ELISA, anti-HIV by EIA, and HCV RNA and HIV RNA by branched DNA and polymerase chain reaction assays to determine if hemophiliacs coinfected with HCV and HIV have higher HCV RNA levels and more active liver disease. Seventy-nine (79%) patients were anti-HCV positive, of whom 85% were HCV RNA positive. None of the anti-HCV-negative patients had detectable HCV RNA in plasma. Forty-two (42%) patients were anti-HIV positive, of whom 47% had detectable HIV RNA. All the anti-HIV-positive patients were also anti-HCV positive. The prevalence of both anti-HCV and anti-HIV increased significantly with age. There was no difference in HCV RNA levels between anti-HIV-positive and anti-HIV-negative patients (mean: 21 +/- 4 vs 18 +/- 5 Meq/ml), although HCV RNA levels were significantly higher in anti-HIV-positive patients with CD4 counts < 200/mm3 (P = 0.008). There was an inverse correlation between HCV RNA levels and CD4 counts but no correlation was found between HCV RNA and serum aminotransferase levels. We found a high prevalence of HCV and HIV coinfection in our hemophiliacs. Hepatitis C virus replication appears to be increased in patients with severe immunodeficiency secondary to progressive HIV infection. However, there was no correlation between HCV RNA and serum ALT level, suggesting that HCV is not directly cytopathic.

Liver-infiltrating and circulating CD4+ T cells in chronic hepatitis C: immunodominant epitopes, HLA-restriction and functional significance

The aim was to assess the specificity and functional significance of liver-infiltrating and peripheral blood T cells in chronic hepatitis C. Peripheral blood mononuclear cells hepatitis C virus from 50 of 58 (86.2%) patients with chronic hepatitis C virus infection and 6 of 28 (21.4%) controls showed a proliferative T cell response to at least one of 16 synthetic peptides covering highly conserved regions of the core, envelope (El) and non-structural regions (NS4) of hepatitis C virus. However, six immunodominant peptides were exclusively recognized by the proliferating blood mononuclear cells from 46 patients with chronic hepatitis C virus infection (79.3%). Fine specificity and HLA-restriction were studied with 15 peptide-specific CD4+ T cell lines and 23 T cell clones isolated from liver tissue and peripheral blood of 12 patients with chronic hepatitis C. It was demonstrated that the peptide-specific response of CD4+ T cells was restricted to the presence of autologous accessory cells and HLA-DR and -DP molecules. Eight peptide-specific T cell lines and five T cell clones derived from liver tissue and peripheral blood, released interferon-gamma (200-6600 pg/ml) and tumor necrosis factor-alpha (100-400 pg/ml) and no or little interleukin-4 (< 140 pg/ml) after peptide-specific or mitogeneic stimulation, thus resembling a Th1-like cytokine profile. Patients with active liver disease showed significantly higher proliferative responses to hepatitis C virus core peptides than asymptomatic hepatitis C virus carriers or complete responders to interferon therapy. In conclusion, class II-restricted CD4+ T cell responses to some immunodominant epitopes within the hepatitis core region correlated with disease activity in chronic hepatitis C virus infection. Functionally, liver-infiltrating and peripheral blood T cells released Th1-like cytokines in response to the specific stimulus. Thus, it can be suggested that CD4+ T cells can mediate the pathogenesis of chronic hepatitis C virus induced liver disease.

Significance of human leukocyte antigens DR3 and DR4 in chronic viral hepatitis

Immune mechanisms have been implicated in chronic viral hepatitis, and these may be influenced by genetic factors. To determine if disease severity in chronic viral hepatitis is associated with the human leukocyte antigens DR3 and/or DR4, 109 patients were evaluated prospectively. The frequencies of DR3 and DR4 in these patients were compared to those in 80 normal subjects. Patients with DR3 and/or DR4 had the same occurrence of severe disease as patients with other DR antigens (21% versus 30%, P = 0.3). Patients with DR3, however, had higher serum gamma globulin and immunoglobulin G levels than patients with DR4 and a greater frequency of severe disease (36% vs 12%, P = 0.046). Patients with DR4 had concurrent immunologic diseases more commonly than patients with DR3 (44% vs 9%, P = 0.005) and patients with other DR antigens (44% vs 9%, P = 0.0002). Patients with DR4 but not DR3 had severe disease less frequently than other patients (9% vs 31%, P = 0.02). The frequencies of DR3 in patients with severe disease (37% vs 18%, P = 0.06) and DR4 in patients without severe disease (44% vs 30%, P = 0.07) were different than those in normal subjects but not to a statistically significant level. We conclude that patients with DR3 and DR4 have different clinical and laboratory findings and disease severity. Patients with DR4 have milder disease than patients with other DR antigens. Disease severity, however, is not closely associated with DR3 or DR4.

High proportion of false positive reactions among donors with anti-HCV antibodies in a low prevalence area

Among 39,656 voluntary blood donors in Okinawa Prefecture, Japan, 115 (0.29%) were repeatedly reactive for antibody to hepatitis C virus (anti-HCV) by second generation (2nd-gen) passive hemagglutination assay (PHA). Positive serum samples were tested for anti-HCV using three different enzyme immunosorbent assays (ELISAs; Abbott 2nd EIA, UBI-HCV-EIA, JCC-2) and for HCV-RNA by the polymerase chain reaction (PCR). The 115 2nd-gen PHA-positive sera were divided into three groups according to the agglutination titers; > 2(10) (high titer group), 2(7)-2(9) (median), 2(5)-2(6) (low). All but one serum (44/45) in the high PHA titer group reacted in each of the three second screening ELISAs. Furthermore, 43 (97.7%) of the 44 sera contained HCV-RNA by PCR. In the median titer group, 11 of the 13 samples tested were positive by each of the three ELISAs, and 4 (36.4%) of the 11 showed reaction by PCR. On the other hand, all of the 38 sera tested in the low titer group were negative for HCV-RNA by PCR, and 24 of the 38 were also negative by each of the three ELISAs. Most of the low titer positive reactions in the 2nd-gen agglutination assay seemed to be false positive. In Okinawa Prefecture, the prevalence of anti-HCV among blood donors is much lower than in the rest of Japan (0.29% vs. 1.11%). Moreover, a significant proportion of these sera were low titer by the PHA assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Ethnic differences in the prevalence of anti-hepatitis C antibodies and hepatitis B surface antigen in Israeli blood donors by age, sex, country of birth and origin

The presence of anti-hepatitis C virus (HCV) antibodies frequently indicates both persistent infection and infectivity. Consequently, blood donors found to be anti-HCV positive, are excluded from the donor pool. The aim of this study was to compare age, sex and ethnic differences in the prevalence of anti-HCV antibodies with that of hepatitis B surface antigen (HBsAg) among immigrant and Israeli-born blood donors. Anti-HCV antibodies were assayed by a second-generation enzyme-immunoassay (EIA) and HBsAg by a standard EIA in a sample of 136,977 blood donors in Israel during 1992. The overall age-adjusted prevalence of anti-HCV antibodies was 0.66% in men and 0.55% in women, and for HBsAg, 0.85% and 0.44%, respectively. There was a significant increase in the prevalence of anti-HCV antibody with age, and significant differences by country of birth, with the highest prevalence found among those born in the former USSR and eastern Europe. This contrasted with the findings for the prevalence of HBsAg, where the highest rates were among those born in northern Africa. Among Israeli-born donors, differences in the prevalence of anti-HCV antibodies by parental country of origin were minimal and much less than for HBsAg. Hence the prevalence of anti-HCV antibodies in Israel is strongly associated with age and country of birth but not with country of origin. There is little evidence of substantial vertical or intrafamilial transmission of HCV infection in Israel.

Significance of IgG and IgM HCV antibody secretion in vitro in patients with chronic hepatitis C: correlation with disease activity and response to interferon-alpha

Hepatitis C virus antibodies are found in the serum of most patients with chronic hepatitis C. However, the significance of the humoral response is still uncertain. In this study, in vitro IgG and IgM anti-hepatitis C virus secretion by peripheral blood mononuclear cells of patients with chronic hepatitis C was analyzed. Peripheral-blood mononuclear cells from 21 of 36 patients (58.3%) secreted IgG anti-hepatitis C virus in vitro, as demonstrated with anti-hepatitis C virus-specific enzyme immunoassays and recombinant immunoblot assays. Ten of the 36 patients (27.8%) showed both IgG and IgM anti-hepatitis C virus core in vitro. In 9 of these 10 patients, IgM anti-hepatitis C virus was also detected in serum. Patients with in vitro IgM or IgG anti-hepatitis C virus secretion had higher ALT levels in serum than did patients without such secretion in vitro (99.5 +/- 22.1 and 85.6 +/- 34.4 vs. 38.1 +/- 37.4 U/L; p < 0.0001, p < 0.001). Furthermore, with a histology activity score it was demonstrated that patients with in vitro IgM or IgG HCV antibodies (or both) had more severe chronic active hepatitis than did patients without in vitro hepatitis C virus antibody secretion (p < 0.01). To analyze the therapy outcome, we included in this study 18 patients who had received interferon-alpha previously. Seven of eight in vitro hepatitis C virus antibody-positive patients were nonresponders, whereas the in vitro hepatitis C virus antibody-negative patients were mostly complete therapy responders (8 of 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C: progress and problems

The hepatitis C virus (HCV), a single-stranded RNA virus, is the major cause of posttransfusion hepatitis. HCV isolates differ in nucleotide and amino acid sequences. Nucleotide changes are concentrated in hypervariable regions and may be related to immune selection. In most immunocompetent persons, HCV infection is diagnosed serologically, using antigens from conserved regions. Amplification of RNA may be necessary to detect infection in immunosuppressed patients. Transmission by known parenteral routes is frequent; other means of spread are less common and may represent inapparent, percutaneous dissemination. Infection can lead to classical acute hepatitis, but most infected persons have no history of acute disease. Once infected, most individuals apparently remain carriers of the virus, with varying degrees of hepatocyte damage and fibrosis ensuing. Chronic hepatitis may lead to cirrhosis and hepatocellular carcinoma. However, disease progression varies widely, from less than 2 years to cirrhosis in some patients to more than 30 years with only chronic hepatitis in others. Determinants important in deciding outcome are unknown. Alpha interferon, which results in sustained remission in selected patients, is the only available therapy. Long-term benefits from such therapy have not been demonstrated. Prevention of HCV infection by vaccination is likely to be challenging if ongoing viral mutation results in escape from neutralization and clearance.

Hepatitis C virus antibodies and virus replication in asymptomatic blood donors

We assessed hepatitis C virus (HCV) infection in 99 asymptomatic blood donors positive using a first-generation HCV antibody assay. When tested with second-generation assays, 86 (87%) donors were reactive (group 1), 2 (2%) were indeterminate (group 2), and 11 (11%) were non-reactive (group 3). Viraemia was revealed by polymerase chain reaction in all group 1 cases. The 2 group 2 cases and 6 (55%) group 3 cases were also viraemic. Viraemia was confirmed by a branched DNA assay in the 2 group 2 cases and 4 (36%) group 3 cases. Serum HCV RNA levels were further studied using a competitive reverse transcription-polymerase chain reaction assay. All cases in groups 2 and 3 were low viraemic (range 10(4)-10(5.5) copies/ml) compared with the 9 group 1 cases examined (range 10(7)-10(9) copies/ml). No correlation was evident between viraemic levels and antibody cut-off index in the first-generation assay. These findings indicate the possibility that low levels of viraemia can occur in individuals non-reactive in second-generation HCV antibody assays.

Rapid and sensitive method for detection of hepatitis C virus RNA by using silica particles

We describe a rapid, sensitive, and economic method for detection of hepatitis C virus (HCV) RNA. This method uses silica particles for purification of nucleic acid and then a modified reverse transcription-PCR that minimizes the risk of contamination and reduces the amount of reagents used. We found purification by silica particles to be at least as sensitive and in certain circumstances more sensitive than that by traditional phenol-chloroform extraction. This improved sensitivity may be due to more efficient recovery of HCV RNA by silica particles. HCV RNA appears to bind to silica particles in a saturable fashion, and the addition of extraneous nucleic acids (salmon sperm DNA or tRNA) decreases the binding in a dose-related fashion. The reverse transcription-PCR is performed by using a modified single tube method which further simplifies and reduces the cost of this assay. Finally, this method may be applied to clinical specimens such as liver tissue.

Detection of hepatitis C virus RNA in the ultrasonic dissector irrigating solution used in liver surgery

Hepatitis C virus (HCV) RNA was detected in the irrigating solution aspirated by the ultrasonic dissector system used in liver surgery with a reverse transcription polymerase chain reaction technique and was then compared with HCV RNA in the serum to clarify the risk of viral transmission to hospital personnel. The positivity of HCV RNA in the aspirated irrigating solution was approximately equal in all patients whose serum was positive for HCV RNA. However, viral RNA was not detected in the aspirated irrigating solution of any patient who was seronegative for HCV RNA. These results indicate that it is necessary to be cautious regarding the transmission of HCV during liver surgery when using the ultrasonic dissector in HCV RNA seropositive patients, because the irrigating solution aspirated by this device appears to be highly infectious.

A study of primary- and re-infection with hepatitis C virus in blood transfusion recipients

A nested polymerase chain reaction was used to assess viraemia in blood transfusion recipients with no serological evidence of hepatitis C virus (HCV) infection (naive recipients) and in recipients with prior or existing HCV infection (infected recipients), who were transfused with HCV-positive blood. In 10 hepatitis cases in naive recipients, defined as primary infection, nine showed clinical hepatitis, and one was sub-clinical; the time between transfusion and elevation of alanine aminotransferase (ALT) levels was 15-60 days (37.9 +/- 13.9). All 10 naive recipients showed abnormal ALT, and 10/10 and 7/10 were persistently positive for anti-HCV and HCV-RNA, respectively, for more than 1 year. Similarly, in five cases in previously infected recipients, defined as re-infection, 4/5 showed clinical hepatitis, the time to elevation of ALT was 30-46 days (34.8 +/- 6.4), and 5/5 and 3/5 were persistently positive for anti-HCV and HCV-RNA, respectively, for more than 1 year. All five infected recipients showed abnormal ALT. In conclusion, there was no significant difference (P = 0.05) in the frequency of the markers of infection resulting from primary or re-infection with HCV, suggesting that primary infection fails to induce a protective immune response.

Quantitation of hepatitis C virus RNA in liver transplant recipients

BACKGROUND/AIMS

Hepatitis C virus (HCV) infection is common in liver transplant recipients, yet the effects of immunosuppression on HCV RNA levels and the relationship of HCV RNA levels to hepatic damage have not been studied.

METHODS

To explore these issues, we measured HCV RNA in serum by polymerase chain reaction amplification and branched DNA assay from 100 HCV-infected patients undergoing liver transplantation.

RESULTS

Mean posttransplant levels were 16-fold higher than pretransplant values (7,935,000 and 496,000 Eq/mL, respectively; n = 65; P < 0.0001). Patients with high pretransplant levels had higher mean posttransplant levels than those with low pretransplant levels (17,119,000 and 6,504,000 Eq/mL, respectively; P = 0.064). Posttransplant levels were similar in patients with recurrent and acquired infection and were independent of time of sampling. Fifty percent of patients with HCV infection had normal liver biopsy specimens, and there was no strong relationship between level of viremia and degree of hepatic damage.

CONCLUSIONS

HCV RNA levels increase markedly following liver transplantation. The frequent finding of viremia in the absence of histological hepatitis suggests that a "carrier state" is common. Absence of allograft damage in some (despite high levels of viral RNA) suggests that in immunosuppressed patients, HCV infection may be tolerated without direct hepatic damage.

Follow-up study of acute hepatitis C

An extended follow-up study of hepatitis C virus (HVC) infection was conducted in Guangzhou and its nearby regions on patients hospitalized with acute hepatitis. Routine screening of blood donors for HCV was not yet instituted at the time of this study. HCV was found to be a common cause of the disease, and the infection had a close association with recent histories of blood transfusion. Sequential sera obtained from patients during hospitalization and after discharge were tested for the presence of HCV antibodies by the first and the second generation of commercial test kits, for levels of alanine aminotransferase (ALT), and for the presence of HCV-RNA. The development of HCV antibodies in some of the patients may be delayed for protracted period following clinical onset. HCV-RNA was only intermittently detectable both before and after seroconversion. Six of 33 patients studied showed seroreversion and 5 of them were accompanied by loss of HCV-RNA and serum ALT returned to normal levels. The disease persisted in 24 of 27 patients without seroreversion, accompanied by intermittent detection of HCV-RNA throughout the protracted course of the infection. Our results indicate that both EIA for detection of HCV antibodies and PCR for serum HCV-RNA should be used in combination for reliable diagnosis of HCV infection and screening of blood for transfusion.

Hepatitis C virus replication and antibodies to structural and nonstructural viral proteins in chronic hepatitis C

The correlation between hepatitis C virus replication and antibodies to both structural (core) and nonstructural (C100-3) hepatitis C virus proteins (anti-HCVcore and anti-C100-3, respectively) was assessed. The concentration of serum hepatitis C virus RNA was determined by a competitive reverse transcription-polymerase chain reaction assay, and antibody titers were determined by endpoint dilution. No correlation was found between viremic levels and antibody titers in 42 chronic hepatitis C patients. At the end of a 6-month course of interferon-alpha therapy, 18 patients became negative for hepatitis C virus RNA. In the other 24 patients, post-treatment viremic levels ranged from 10(-6.5)-10(0.5) of pretreatment levels. Both anti-C100-3 and anti-HCVcore frequently decreased in patients whose viremic levels dropped to the negative range or to < 10(-2) of pretreatment levels. Anti-C100-3 decreased in all such cases (25/25), while anti-HCVcore decreased in 18/25 (72%) (p < 0.01), indicating that anti-C100-3 is more likely to decrease following suppression of viral replication than anti-HCVcore. These data suggest that hepatitis C virus antibodies may serve as a marker of suppression of viremia following interferon therapy even in patients who do not clear the virus.

Hepatitis C virus genotypes are not responsible for development of serious liver disease

Although hepatitis C virus (HCV) is known to have at least four kinds of genotypes, no clear relationship has yet been established between the genotype and the severity of liver disease. Therefore, we determined HCV genotypes in sera of 251 Japanese patients with type C chronic liver disease, using polymerase chain reactions with six independent primers. One set of primers and a probe derived from 5'-noncoding region of HC-J1 was supposed to detect all four genotypes, while the other five were devised to detect each of the genotypes. Among the patients, the major genotype was type II (69%) and the second most common was type III (18%). Type IV was found in 7%, while none had type I genotype. There was no significant difference in the distribution of any genotype among different stages of liver disease, although the ratio of type II to type III tended to be higher in the group of cirrhosis and hepatocellular carcinoma than in the chronic hepatitis group (5.5 vs 3.0). The amounts of HCV RNA were significantly greater in patients with type II (P < 0.001) compared with those with types III and IV. However, HCV concentrations of each genotype were not associated with the disease status. These results suggest that HCV genotypes are unlikely to be responsible for the development of more serious liver disease.

Longitudinal study of hepatitis C viremia in chronic hepatitis C

Serial serum samples from 20 untreated patients with chronic hepatitis C virus (HCV) infection were tested for HCV RNA by a nested polymerase chain reaction assay using primers from the highly conserved 5' noncoding region to determine the relationship between hepatitis C viremia and the activity of liver disease during the natural course of chronic HCV infection. Semiquantitation of serum HCV RNA level was achieved by testing serial 10-fold dilutions of RNA extracts to determine the end-point titer. All the patients were HCV RNA positive at presentation. There was a poor correlation between the initial HCV RNA titer and serum transaminase levels. All patients except one were persistently HCV RNA positive during a follow-up period of 1.5-15 years, although 17 (85%) had periods of normal or near-normal transaminase levels. There was no correlation between changes in the serum transaminase levels and HCV RNA titer. Patients with chronic HCV infection have persistent viremia despite fluctuations in ALT levels.

Importance of the polymerase chain reaction in the study of hepatitis C virus infection

Recently, the principal etiological agent of parenterally transmitted non-A, non-B hepatitis was molecularly cloned from the plasma of an experimentally infected chimpanzee and has been named hepatitis C virus. Determination of the complete nucleotide sequence of the hepatitis C virus genome was a crucial step in preparing the way for future study of this medically important human pathogen. Due to the very low concentration of virus in serum, amplification of viral RNA sequences by reverse transcription and polymerase chain reaction is the only practical method currently available for demonstrating viremia in patients with hepatitis C virus infection. This review examines the pivotal role of the polymerase chain reaction in understanding the biology of hepatitis C virus.

Prevention of posttransfusion hepatitis B and C by screening for antibody to hepatitis C virus and antibody to HBcAg

Screening of blood donors by testing for antibody to HBcAg and antibody to hepatitis C virus is commonly done. However, the applicability of these screening tests may vary depending on the prevalence of hepatitis B virus and hepatitis C virus infection in various populations. We have therefore prospectively evaluated 158 adult patients who received blood or blood products during open-heart surgery in Hong Kong to compare the efficacy of various serological screening tests in the prevention of posttransfusion hepatitis. Serum from five (0.5%) donors was positive for antibody to hepatitis C virus by second-generation enzyme immunoassay; in two, optical-density readings in enzyme immunoassay were greater than 2.0, but only one was positive for hepatitis C virus RNA by reverse transcription-polymerase chain reaction. The latter donor was also positive for antibody to HBcAg and had elevated serum ALT activity. The recipient of a unit of this donor's blood was the only one in whom posttransfusion hepatitis C developed (0.1% per unit transfused). Screening with antibody to hepatitis C virus was more specific than that with antibody to HBcAg or ALT in excluding donors from transmitting hepatitis C (99.6%, 79.4% and 98.8%, respectively). Both the sensitivity and negative predictive value of screening for antibody to hepatitis C virus were 100%, but the positive predictive value was only 20%. Forty-five blood recipients were considered susceptible to hepatitis B virus infection because testing for hepatitis B serology in serum (HBsAg, antibody to HBsAg and antibody to HBcAg) was negative before being transfused. Asymptomatic hepatitis B seroconversion developed in three (6.7%) recipients (1.1% per unit transfused).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody response to core, envelope and nonstructural hepatitis C virus antigens: comparison of immunocompetent and immunosuppressed patients

Some immunosuppressed patients with hepatitis C virus infection do not have detectable levels of antibody to hepatitis C virus on second-generation enzyme immunoassay. Antibodies to the envelope and nonstructural region 5 proteins have not been examined. Four groups of patients with hepatitis C virus infection were studied: (a) 20 immunocompetent patients, (b) 15 hemodialysis patients, (c) 17 kidney transplant recipients and (d) 3 acute leukemia patients who underwent bone marrow transplantation. Serum samples were tested for antibody to hepatitis C virus with a second-generation enzyme immunoassay and multi-antigen enzyme immunoassays and for hepatitis C virus RNA with a nested polymerase chain reaction assay. All the immunocompetent patients reacted to C25, C22 and C33C; 90% reacted to nonstructural region 5 antigen and 80% reacted to C100-3. Only 55% reacted against yeast-derived e1 and e2 antigens, but all reacted against vaccinia virus--expressed N e1 and e2 antigens, indicating that the envelope epitopes are conformational and glycosylated. Sixty-five percent to 90% of dialysis and kidney transplant patients reacted to C25, C22 and N e1 and e2, but only 12% to 60% reacted to C100-3, C33C and nonstructural region 5 antigen. Diminution or loss of reactivity to hepatitis C virus antigens was observed after kidney and bone marrow transplantation, with C25 and N e1 and e2 less affected. Our data suggest that incorporation of C25 and N e1 and e2 antigens in the assay for antibody to hepatitis C virus would improve the detection of hepatitis C virus infection in immunosuppressed patients.

Detection of HCV RNA using reverse transcription and nested polymerase chain reaction in chronic non-A, non-B liver diseases in Korea

To investigate the interrelationship between the anti-HCV prevalence and the HCV RNA positivity in chronic non-A, non-B (NANB) liver diseases in Korea (n = 137), we performed RT-nested PCR using 4 primers in the 5'-noncoding region of HCV genome. The overall HCV RNA positive rates were 62.8%; 87.7% (57/65) of anti-HCV positive cases and 40.3% (29/72) of anti-HCV negative cases. Four patterns according to the combination of anti-HCV and HCV RNA assays could be observed; 41.6% in [anti-HCV+/HCV RNA+], 5.8% in [anti-HCV+/HCV RNA], 21.2% in [anti-HCV+/HCV RNA], and 31.4% in [anti-HCV+/HCV RNA]. Our results suggested that HCV may be still related to chronic NANB liver diseases negative for anti-HCV, and other unknown agents, so-called non-B non-C, might be accounted for patients negative for both, although a low concentration of HCV RNA, or the presence of HCV RNA or HBV DNA in liver tissue should be excluded.

Hepatitis C virus RNA in southern African blacks with hepatocellular carcinoma

We used a sensitive and specific cDNA polymerase chain reaction assay to detect hepatitis C virus (HCV) RNA in serum samples from 128 unselected southern African Blacks with hepatocellular carcinoma (HCC) and found HCV RNA in 26 (20.3%) of these patients. Antibodies to HCV (anti-HCV) were detected in 59 patients (46.1%) with a first-generation ELISA test, and only 19 of these patients were HCV RNA-positive. Anti-HCV was detected in 25 patients (19.5%) with a second-generation ELISA test, and 17 of these patients were HCV RNA-positive. Among the second-generation ELISA- and HCV RNA-positive patients, 14 were anti-HCV positive, 2 were indeterminate, and 1 was anti-HCV negative in a second-generation recombinant immunoblot assay, whereas all patients who were second-generation ELISA positive, but HCV RNA negative, were anti-HCV negative in this immunoblot assay. A total of 5 patients were negative in both ELISA tests but were HCV RNA positive. Seventy-one patients (55.5%) had evidence of a current HBV infection, 50 (39.1%) had evidence of a previous infection, and 7 (5.5%) had no evidence of a current or previous HBV infection. The prevalence of current HBV infection was significantly lower in patients who were positive for HCV RNA than in those who were negative (P = 0.001). This difference was not dependent on sex, age, or geographical location of the patients. The mean age of HCC patients positive for HCV RNA (52.3 years) was significantly higher (P < 0.001) than that of negative patients (40.3 years), and the difference was not dependent on HBV status or geographical location. Patients positive for HCV RNA were more likely to be urban than were negative patients. Thus, a significant number of southern African Blacks with HCC had a current HCV infection but not a current HBV infection, further suggesting that infection with HCV plays a role, albeit minor, in the development of HCC in this population.

A prospective study of hepatitis C virus infection among renal transplant recipients

BACKGROUND

Chronic non-A, non-B hepatitis is a major cause of liver disease in renal transplant recipients.

METHODS

One hundred eight-five renal allograft recipients, including 151 who had been prospectively followed up for 24 months, were studied to determine the prevalence and course of hepatitis C virus (HCV) infection. Antibody to HCV (anti-HCV) was measured by enzyme immunoassay, and HCV RNA was measured by nested polymerase chain reaction assay.

RESULTS

Twenty-three (12.4%) patients were positive for anti-HCV and/or HCV RNA: 19 (10.3%) were anti-HCV positive; and HCV RNA was detected in 18 (94.7%) anti-HCV-positive and 4 (2.4%) anti-HCV-negative patients. Markers of HCV infection persisted in all HCV-positive patients over the 2-year period. Most HCV-positive patients acquired HCV infection before or at the time of transplantation. The incidence of new infection after transplantation was 0.45% per patient-year. Anti-HCV and/or HCV RNA was detected in 75% of patients with biochemical chronic non-A, non-B hepatitis, but transaminase levels were persistently normal in 30.4% of HCV-positive individuals.

CONCLUSIONS

HCV infection is common among renal transplant recipients. Testing for HCV RNA is important because some patients might not produce anti-HCV. Transaminase levels cannot be used as a surrogate marker of HCV infection in these patients.

Prevalence of hepatitis C virus infection in hemodialysis patients: a longitudinal study comparing the results of RNA and antibody assays

We longitudinally studied 51 patients from two hemodialysis centers to determine the prevalence of hepatitis C virus infection in hemodialysis patients. Serum samples were tested for antibody to HCV by first- and second-generation enzyme immunoassays and for hepatitis C virus RNA by nested polymerase chain reaction assay. Antibody to hepatitis C virus was detected in the initial serum samples by first-generation enzyme immunoassay and second-generation enzyme immunoassay in 6 (11.8%) and 11 (21.6%) patients, respectively. First-generation enzyme immunoassay had a false-positive rate of 33.3% and a false-negative rate of 63.6%. Hepatitis C virus RNA was found in eight second-generation enzyme immunoassay-positive patients (72.7%) and in one patient negative for antibody to hepatitis C virus (2.5%) giving an overall positivity rate of 17.6%. After 19 mo, antibody to hepatitis C virus was detected in 15 patients (29.4%) on second-generation enzyme immunoassay; hepatitis C virus RNA was found in 13 patients (25.5%). Hepatitis C virus markers persisted in all 12 patients with initial evidence of hepatitis C virus infection. Three patients acquired hepatitis C virus infection during the interim, giving a new infection rate of 4.9% per patient-year. Antibody to hepatitis C virus, hepatitis C virus RNA or both was detected in 55.6% of patients with biochemical changes suggestive of non-A, non-B hepatitis. Of the 15 antibody to hepatitis C virus, second-generation enzyme immunoassay-positive patients, 66.7% had persistently normal serum transaminase levels. In summary, hepatitis C virus infection is common among hemodialysis patients. First-generation enzyme immunoassay is an unreliable assay for antibody to hepatitis C virus in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)