Influence of the genotypes of hepatitis C virus on the severity of recurrent liver disease after liver transplantation

Hepatitis C virus genotypes: epidemiological and clinical associations. Benelux Study Group on Treatment of Chronic Hepatitis C

In a cohort of 292 chronic hepatitis C patients living in the Benelux countries the relationship between viral genotype and geographical origin, route of transmission, clinical characteristics and severity of liver disease was analyzed. HCV-RNA isolates could be classified by the Line Probe Assay (LiPA) as 1a, 1b, 2, 3, 4 or 5 in 286 (98%) cases. Patients of European origin were predominantly infected with HCV subtype 1b (164/254, 65%, CI 58-70%), as were patients of Asian origin (7/13, 54%). Patients originating from Surinam (South America) had predominantly type 2 (9/10, 90%), whereas Africans were mainly infected with type 4 (7/9, 77%). Blood transfusion was the mode of transmission in 142 (50%) patients, intravenous drug abuse (IVDA) in 40 (14%), occupational needle accident or tattoo in 11 (4%); no obvious source of infection was found in 93 (33%). In patients infected by blood transfusion, subtype 1b was predominant (70%, CI 61-77%), whereas subtypes la and 3 were predominant in those infected by IVDA (25% and 45%, respectively, p<0.001). Cirrhosis was observed in 68 (24%) patients; in multivariate analysis, factors independently related to cirrhosis were: the duration of infection, age and prior hepatitis B. No significant relationship was found between the severity of fibrosis or liver inflammation and the HCV (sub)types. In summary, in this large cohort of patients in the Benelux countries the hepatitis C virus (sub)type present was clearly related to the country of origin and the route of transmission, but not to the severity of liver disease.

Early development of chronic active hepatitis in recurrent hepatitis C virus infection after liver transplantation: association with treatment of rejection

BACKGROUND/AIMS

We retrospectively studied 63 consecutive patients (mean age 54+/-8) with hepatitis C virus genotype 1b recurrence after liver transplantation and with a minimum histological follow-up of 1 year, in order to determine whether an early severe recurrence, defined as the development of chronic active hepatitis within the first 2 years post-liver transplantation, was associated with increased immunosuppression.

METHODS

The 1st year immunosuppression data (rejection episodes, boluses of methyl-prednisolone, cumulative doses of prednisone and azathioprine, OKT3 use) were recorded, and evaluated as predictive of severe recurrence at 1 and 2 years post-liver transplantation. Chronic active hepatitis and rejection were defined by histological criteria. Immunosuppression consisted of cyclosporine, azathioprine and prednisone. The treatment of rejection was based on a "bolus" of 1 g methyl-prednisolone/3 days.

RESULTS

At 1 year, 64% (40/63) of the patients had chronic active hepatitis, whereas of the 40 patients who had a 2nd year biopsy available, 75% had chronic active hepatitis at 2 years. At 1 year post-liver transplantation, no significant association was observed between immunosuppression and the development of chronic active hepatitis. In contrast, at 2 years, rejection (p=0.006), treatment of rejection (p=0.05), methyl-prednisolone boluses (p=0.013) and the number of rejection episodes (p=0.0034) occurring during the 1st year post-liver transplantation were significantly more common in patients with chronic active hepatitis. There was also a trend towards higher cumulative steroids (9447+/-3176.5 vs 7891.5+/-2111 mg) and higher cumulative azathioprine doses (13472+/-11154 vs 6233.5+/-5937 mg) in patients with chronic active hepatitis as compared to those who did not develop chronic active hepatitis.

CONCLUSIONS

Rejection and/or its treatment may accelerate the natural history of hepatitis C virus genotype 1b infection post-liver transplantation.

Risk factors for hepatocellular carcinoma and its incidence after interferon treatment in patients with chronic hepatitis C. Osaka Liver Disease Study Group

To elucidate the risk factors for liver carcinogenesis and to examine the incidence of hepatocellular carcinoma (HCC) after interferon therapy, 1,022 chronic hepatitis C patients treated with interferon were followed by ultrasonography for 13 to 97 months (median 36 months). Sustained response with prolonged alanine aminotransferase normalization was found in 313 patients, transient response with alanine aminotransferase relapse after therapy in 304, and no response in 405. Forty-six developed HCC, of whom 5 were sustained responders, 9 were transient responders, and 32 were nonresponders. The cumulative incidence of HCC in transient responders was almost equal to that in sustained responders, and it was significantly higher in nonresponders than in sustained and transient responders (P=.0009). The seventh-year cumulative incidence rates of HCC in sustained responders, transient responders, and nonresponders were estimated to be 4.3%, 4.7%, and 26.1%, respectively. However, there was no significant difference in the cumulative incidence of HCC between patients with HCV subtype 1 and 2 (P=.14). Cox regression analysis showed that the risk of HCC development was not elevated in transient responders compared with sustained responders, but that the risk was 7.90-fold higher in nonresponders than in sustained responders (P=.008). Patients > or =55 years of age had a significantly higher risk ratio (4.65) than did those under 55 years of age (P=.006). The risk of HCC development in men was 4.35 times higher than the risk in women (P=.02). However, the degree of fibrosis was not a significant risk factor for the development of HCC (risk ratio, 3.16; P=.052). These results suggest that patients in the high-risk group of HCC after interferon therapy were those who showed no response, those who were older, and those who were male, and that such patients should be carefully followed using ultrasonography.

Large-scale analysis of hepatitis C virus serological typing assay: effectiveness and limits

The HCV (hepatitis C virus) Serotyping 1-6 Assay (Murex Laboratories) was evaluated on 303 French HCV-infected patients. Serological typing results were compared to the genotypes obtained from sequence analyses of the 5' noncoding regions of the virus genome from 46 HCV-infected patients, and assay specificity was found to be high (97.6%). The serological typing assay, run in 257 consecutive HCV-infected patients, yielded an assay sensitivity lower (70.6%) than that previously reported. This finding was attributed mainly to nonreactive sera from human immunodeficiency virus (HIV)-positive patients (P < 0.001) and perhaps reflected cryoglobulin positivity in others. No anti-type 6 reactivity was detected, and the overall serological type distribution values for types 1 to 5 were 67.3, 7.9, 16.4, 6.6, and 0.9%, respectively. A higher prevalence of type 4 was noted among HIV-infected patients (P < 0.001). In addition, serotype 2 was significantly more frequent in cryoglobulinemia positive than in cryoglobulinemia-negative patients (P < 0.05). Although an initial high level (7%) of mixed serological typing reactivities was found, after predilution of serum only two mixed infections could be confirmed (0.9%). It is suggested, therefore, that mixed reactivities have to be interpreted carefully and retested with prediluted serum, particularly when the optical density of the reactivity is > 2.5 or remains > 0.4 after competition with all type-specific peptides. The high specificity and relatively good sensitivity even in immunocompromised patients obtained with this assay indicate that it can be used routinely. Because response to treatment is linked to HCV type, this assay could be used to identify HCV serotype to guide therapeutic decisions.

[Update on hepatitis C virus: its variability and the implications]

Hepatitis C virus (HCV) is the main etiologic factor of post-transfusional and sporadic hepatitis, called non-A non-B in the past. These infections are characterized by a very high number of chronic carriers always with a persistent viral increase, but often at a slow pace. The seriousness of liver disease differs from one individual to another, varying from an asymptomatic form with minor or no liver injuries, to cirrhosis and hepatocellular carcinoma. Physiopathological mechanisms involved in liver injuries are still poorly understood. The direct role of immune response and of possible genetic factors is still under study. This review aims at summing up the discovery of HCV, its structure, and its variability in the various genome regions in the same individual and from one individual to another. The different methods and techniques to analyze this variability are also reviewed, as well as the various suggested ways of classifying the different types. The geographical distribution and both clinical and biological consequences of this variability are also discussed.

[Biology of hepatitis C viruses: clinical implications]

Infection by hepatitis C virus is characterized by a high rate of chronicity and low viremia. The virus has only been recently identified; it is a positively stranded RNA virus which shows homology in its genetic organisation with the pestiviruses and flaviviruses. There is not yet an efficient culture system available. Evidence indicates that the genetic variability of the HCV genome might have important clinical implications.

No evidence of HCV infection or liver disease in British patients with oral lichen planus

An association between chronic hepatic disease and/or hepatitis C (HCV) infection and lichen planus (LP) has been described in patients from Italy, Japan and Spain. There are no data on the frequency of the association with HCV in British patients. In the present investigation, the HCV seropositivity and liver function status of 55 British patients with oral LP were assessed and compared with these parameters in 110 healthy control subjects. None of the patients with LP or control subjects had serum IgG antibodies to HCV or had abnormal liver function. It was concluded that while LP may be associated with HCV infection and liver disease in some southern European and other patients, such a co-occurrence was not detected in British patients.

Diagnostic tools in the evaluation of patients with viral hepatitis undergoing liver transplantation

Familiarity with the diagnostic parameters of viral hepatitis is imperative in the liver transplantation arena. Chronic viral hepatitis B and C are among the most common categories of end-stage liver disease. The preoperative diagnosis, determination of recurrent infection, and the assessment of antiviral therapeutic efficacy are dependent on appropriate virological testing. Furthermore, liver transplant personnel are at a high risk for parenterally transmitted viral hepatitis infection. Knowledge and understanding of the serological patterns of acute and chronic viral hepatitis, as well as recognition of the immune status for one or more of these viruses, will facilitate prevention and treatment of viral hepatitis for these health care providers.

The influence of hepatitis C virus genotypes on the outcome of liver transplantation

BACKGROUND

The aim of this study was to report the influence of hepatitis C virus (HCV) genotypes and HLA matches on the outcome of liver transplantation, hepatitis recurrence, and progression to cirrhosis after transplantation.

METHODS

HCV genotypes were determined from pretransplantation sera and/or liver explant tissues from 202 patients with HCV-related end-stage liver disease. One hundred fifty patients with known infecting genotype for whom posttransplantation biopsy specimens were available or who had normal results of liver injury tests constituted the group analyzed. Patients were followed up for up to 4.5 years. Hepatitis activity index scores at the time of disease recurrence were used to assess disease activity. Cirrhosis was diagnosed by using histological evidence. The number of HLA matches with respect to A, B, DR, and DQ loci was determined.

RESULTS

The rates of hepatitis recurrence were 25% and 75% at 1 year and 4 years, respectively; Kaplan-Meier survival analysis did not reveal significant differences between the infecting genotypes with respect to overall rates of survival or recurrence of hepatitis. At hepatitis recurrence, hepatitis activity index scores did not differ between the genotype groups. The distribution of infecting genotypes among the 7 patients who developed cirrhosis is reflective of pretransplantation distribution. Neither HLA site-specific nor total matches affected the rates of survival or disease recurrence.

CONCLUSIONS

The infecting HCV genotype had no influence on the incidence or severity of recurrent hepatitis, rate of survival, or development of cirrhosis. HLA matching does not influence transplantation outcome for HCV-related disease.

Cholestatic hepatitis after liver transplantation is associated with persistently high serum hepatitis C virus RNA levels

Viral recurrence is universal after transplantation for hepatitis C infection. This may lead to difficulties in differentiating allograft dysfunction caused by chronic rejection from hepatitis C virus (HCV) recurrence. Cases of severe cholestatic hepatitis have also been reported in conjunction with reinfection of the graft with HCV. Patients receiving transplants for HCV-related liver disease were studied before and after transplantation by HCV RNA quantitation of serial serum samples. Four major clinical patterns of HCV recurrence could be distinguished posttransplantation: group 1, asymptomatic hepatitis with no significant symptoms; group 2, cholestatic hepatitis with centrilobular ballooning; group 3, hepatitis leading to chronic allograft rejection; and group 4, persistently normal serum aminotransferase levels. Pretransplantation viral load was shown to be an important indicator of disease severity because the group 2 patients had significantly higher pretransplantation viral loads than patients in group 1 (P = 0.01) and group 4 (P = 0.005). The group 2 patients also had persistently significantly higher posttransplantation viral loads than the patients in group 1 (P = 0.01) and group 4 (P = 0.02), whereas patients who developed chronic allograft rejection showed marked decreases in serum HCV RNA before retransplantation. Patients from group 4 had the lowest viral loads after transplantation. These results show that persisting graft cholestasis due to HCV is associated with persistently high HCV RNA levels compared with other etiologies of graft dysfunction. Prospective studies are needed to determine whether such quantitation may be diagnostically helpful in distinguishing the different patterns of HCV-related graft dysfunction observed after liver transplantation.

Hepatitis C infection in transplantation

This review emphasizes the role of HCV in the transplant setting. Prolonged HCV infection results in end-stage liver disease and as such represents a common indication for liver transplantation. Recurrence of infection is almost universal after transplantation in those with viremia before transplantation. Acquired disease is uncommon but nevertheless important, particularly in organ populations in whom screening for infection is not routine. The natural history of post-transplantation disease suggests that the effect on graft or patient survival is minor, at least during short-term follow-up. Long-term follow-up is needed, as well as more detailed study of the factors contributing to severity of post-transplantation disease. Kidney transplant recipients are commonly infected with HCV prior to transplantation. HCV infection after transplantation is associated with an increased risk of liver disease and infectious complications, but its effect on survival is still controversial. Similarly, observations in recipients of other solid organ transplants, such as heart and lung, and bone marrow patients suggest that HCV infection usually is not a major cause of mortality in the first 5 to 10 years of follow-up. Many issues still need to be addressed. The most important is the identification of factors that contribute to disease progression. Finally, effective therapies to eradicate infection and prevent disease progression are awaited.

Hepatitis viruses and liver transplantation

Acute and chronic liver diseases related to hepatitis viruses are the main indications for liver transplantation. The risk of viral reinfection after transplantation is the main limiting factor in these indications. The risk of viral B reinfection is: 80% in the absence of prophylaxis; is related to the presence of active viral B replication prior to transplantation; is higher in patients with chronic liver disease, rather than with fulminant hepatitis; and is higher in patients with hepatitis B virus (HBV)-related liver disease alone rather than in those with HBV-hepatitis delta virus (HDV) infection. Post-transplant long-term passive antibody to hepatitis B (anti-HB) immunoprophylaxis reduces the risk of HBV recurrence to 30% in patients with HBV cirrhosis, and to less than 10% in those with fulminant hepatitis B. Patients with HBV-HDV liver disease receiving passive anti-HB immunoprophylaxis are at low risk of HBV recurrence (10-15%), but at high risk of HDV recurrence (80%). However, HDV reinfection of the graft has no clinicopathological consequence in the absence of concomitant HBV reinfection. The five year survival of patients transplanted for HBV cirrhosis and for HDV cirrhosis at the Hepatobiliary Center, Hôpital Paul Brousse is 72% and 85%, respectively. Hepatitis B virus reinfection of the graft is characterized by a high level of viral replication, and a chronic outcome. Antiviral treatments such as ganciclovir, adenine arabinoside monophosphate, famcyclovir, and lamivudine have a place after transplantation and may stop HBV replication, ganciclovir, famcyclovir and lamivudine should be continued for several months and in some cases indefinitely. Hepatitis C virus reinfection is almost constant, assessed by the persistence of hepatitis C virus (HCV)-RNA in the serum in 90% of cases. Acute lobular hepatitis appeared in 75% of patients at a median of 4 months post transplantation with a range of between 23 days and 4 years. In our series, the 5 year actuarial rate of HCV acute hepatitis on the graft, chronic hepatitis, and cirrhosis, is 75, 60, and 8%, respectively. Hepatitis C virus RNA level is dramatically increased after transplantation and seems to correlate with the occurrence of acute hepatitis on the graft. A positive relation between genotype 1b and prevalence and severity of HCV hepatitis on the graft have been suggested in European series. There is no demonstrated way to prevent HCV reinfection. The use of interferon for the treatment of HCV hepatitis on the graft was disappointing due to a poor antiviral effect and the occurrence of chronic rejection episodes in some patients. Promising results of the combination of interferon and ribavirine have been reported and need confirmation. The 5 year survival of patients transplanted for viral C cirrhosis at the Hepatobiliary Center, Hôpital Paul Brousse is 78%. In conclusion, patients with HBV cirrhosis and without HBV replication are candidates for liver transplantation. Long-term passive anti-HB prophylaxis is the best way to prevent HBV recurrence. Patients with HBV replication should be included in protocols using combinations of antiviral treatments and passive anti-HB immunoprophylaxis. Viral C reinfection is frequent, but medium-term survival is good. However, long-term graft and patient survival remains unknown and methods to prevent and treat HCV reinfection on the graft are needed.

Hepatitis G virus coinfection in hepatitis C virus-infected liver transplant recipients

BACKGROUND

In this study, we determined the prevalence of hepatitis G virus (HGV) infection in end-stage hepatitis C virus (HCV)-related liver disease and examined the influence of HGV coinfection on the outcome of liver transplantation.

METHODS

HGV was detected by reverse transcriptase-polymerase chain reaction and Southern blotting in sera drawn from 159 patients who were known to be HCV infected before transplantation. Patients were followed up for a mean of 28.4 months after transplantation.

RESULTS

Forty-one (25.3%) patients were HGV positive and the prevalence of HGV infection was similar for different HCV genotypes. Both HGV-positive and -negative groups had similar survival, recurrence rates, inflammatory activity scores, and degree of fibrosis at the time of recurrence.

CONCLUSION

Infection with HGV is common in end-stage HCV-infected patients presenting for liver transplantation. It influences neither the outcome of liver transplantation nor the recurrence of hepatitis in the graft.

HCV genotypes in Italian patients with HCV-related oral lichen planus

Hepatitis C virus (HCV) has high genomic variability and since its discovery, six different "types" and an increasing number of "subtypes" have been reported. HCV genotype may influence viral replication, natural history of disease and response to therapy. Recently, an association between lichen planus (LP) and HCV infection has been suggested, as there is an increased frequency of HCV infection among some groups of patients with LP, in particular from Italy and Japan. These results have not been confirmed by other reports from different geographical areas. Since HCV genotypes have a heterogeneous geographical distribution, we have determined by restriction fragment length polymorphism the genotypes of 39 HCV-seropositive Italian patients with oral LP in order to establish whether the association between LP and HCV infection is influenced by HCV subtype. Of the 33 (84.6%) viraemic patients, 17 (51%) were infected by HCV subtype 1b, 9 (27%) were infected by HCV subtype 2a, 2 by subtype 1a and 1 by subtype 2b. In four cases the gel patterns were uninterpretable. This distribution of HCV genotypes is similar to that reported in recent studies of Italian HCV-seropositive patients of unknown LP status. It is concluded from this small sample that the association of lichen planus with HCV infection and its differential geographic distribution is unlikely to be due to infection by a particular HCV genotype.

Hepatitis C virus genotypes in liver transplant recipients: impact on posttransplant recurrence, infections, response to interferon-alpha therapy and outcome

BACKGROUND

End-stage liver disease due to hepatitis C virus (HCV) is the most common indication for liver transplantation in U.S. veterans. We investigated the influence of HCV genotypes on the incidence and timing of recurrent HCV hepatitis, survival, infectious morbidity, and response to interferon-alpha therapy in this unique patient population.

METHODS

HCV genotype was determined by direct sequencing of the NS5 region of HCV with type-specific primers.

RESULTS

Genotype 1a (66%, 32/47) was the predominant genotype. Type 1b was found in 25% (12/47) of patients and type 2b was found in 9% (4/47). Histopathologically recurrent HCV hepatitis developed in 53% (25/47) of the patients after transplantation. This group included 45% (14/31) of the patients with type 1a, 67% (8/12) of the patients with type 1b, and 25% (1/4) of the patients with type 2b (P>0.5). The time to recurrence and the severity of HCV recurrence as defined by aminotransferase levels or Knodell scores were not different among the three genotypes. There was a trend toward a higher incidence of major infections in patients with type 1b (75%) versus type 1a (48%) and type 2b (50%) (P=0.11). The response to interferon-a therapy did not differ significantly among the genotypes. Mortality at 5 years was 16% (5/31) in patients with genotype 1a, 42% (5/12) in patients with genotype 1b, and 50% (2/4) in patients with genotype 2b (P=0.06).

CONCLUSIONS

The incidence, time to recurrence, and response to interferon-alpha therapy did not differ between the various genotypes in our liver transplant recipients. However, there was a trend toward higher infectious morbidity and overall mortality in patients with genotype 1b after transplantation.

Prophylaxis and treatment strategies for chronic viral hepatitis in liver transplant patients

This article highlights the importance of hepatotropic viruses as pathogens in patients undergoing liver transplantation, their contribution to morbidity and mortality after transplantation, and the approach to treatment of these pathogens when they cause disease. Although many advances have been made in the management of viral hepatitis in the transplant setting, there remain unanswered questions about the long-term natural history of the disease. An understanding of the pathogenesis of infection in the setting of transplantation is emerging slowly but requires further investigation. New approaches to treating disease in patients with either HBV or HCV infection are under development and will likely focus on the use of combinations of antiviral and immunomodulatory agents.

Interferon therapy for chronic HCV hepatitis: trick or treat?

Chronic hepatitis caused by the hepatitis C virus (HCV) is a common condition that leads to cirrhosis and hepatocellular carcinoma. Current treatment with interferon is unsatisfactory, with a low percentage of patients who respond and uncertain high-term significance; in addition, it is associated with sometimes severe side effects. The increasing sophistication of molecular biology has enabled viral characteristics such as viral load, genotypes, and quasi-species to be identified, which may help predict a patient's response to interferon treatment. We suggest that interferon therapy for hepatitis C virus should be restricted to referral centers in the context of controlled trials.

Serological determination of hepatitis C virus genotype: comparison with a standardized genotyping assay

In patients with chronic hepatitis C, determination of hepatitis C virus (HCV) genotype could be routinely run in the future to tailor treatment schedules. The suitabilities of two versions of a serological, so-called serotyping assay (Murex HCV Serotyping Assay version 1-3 [SA1-3] and Murex HCV Serotyping Assay version 1-6 [SA1-6]; Murex Diagnostics Ltd.), based on the detection of genotype-specific antibodies directed to epitopes encoded by the NS4 region of the genome, for the routine determination of HCV genotypes were studied. The results were compared with those of a molecular biology-based genotyping method (HCV Line Probe Assay [INNO-LiPA HCV]; Innogenetics S.A.), based on hybridization of PCR products onto genotype-specific probes designed in the 5' noncoding region of the genome, obtained with pretreatment serum samples from 88 patients with chronic hepatitis C eligible for interferon therapy. Definitive genotyping was performed by sequence analysis of three regions of the viral genome in all samples with discrepant typing results found among at least two of the three assays studied. In all instances, sequence analysis confirmed the result of the INNO-LiPA HCV test. The sensitivity of SA1-3 was 75% relative to the results obtained by the genotyping assay. The results were concordant with those of genotyping for 92% of the samples typeable by SA1-3. The sensitivity of SA1-6 was 89% relative to the results obtained by the genotyping assay. The results were concordant with those of genotyping for 94% of the samples typeable by SA1-6. Overall, SA1-6 had increased sensitivity relative to SA1-3 but remained less sensitive than the genotyping assay on the basis of PCR amplification of HCV RNA. Cross-reactivities between different HCV genotypes could be responsible for the mistyping of 8 (SA1-3) and 6% (SA1-6) of the samples. Subtyping of 1a and 1b is still not possible with the existing peptides, but discriminating between subtypes may not be necessary for routine use.

Liver transplantation for hepatitis C-associated cirrhosis in a single Australian centre: referral patterns and transplant outcomes

During the study period, 63 patients with hepatitis C virus (HCV) cirrhosis were referred to our unit for liver transplantation. All cases referred and transplanted were retrospectively examined. Eighty-six per cent of referred patients were male, 35% consumed alcohol in the harmful/hazardous range, 13% were infected with hepatitis B and 7% had hepatocellular carcinoma. Patients with sporadic infection were more likely to be born outside Australia and were an average of 10 years older than those with HCV acquired via intravenous drug use (P < 0.001). However, patients were an average of 12 years younger at referral if they consumed harmful amounts of alcohol than if they abstained (P = 0.002). We examined the impact of HCV on the outcome of 28 patients who underwent liver transplantation (mean follow up 25 months; range 3-76 months). The use of OKT3, HCV genotype and hepatitis B status were examined for their effect on HCV-related graft dysfunction. Three year survival was 84%, equivalent to a control group. Chronic HCV-related graft dysfunction occurred in 15 (56%) patients, of whom 10 had an asymptomatic elevation in serum amino transferase, two had cholestatic hepatitis and three had severe hepatitis C that progressed onto chronic rejection. Hepatitis C virus genotype 1b tended to be associated with HCV graft dysfunction (5/6 type 1b vs 10/16 in non-type 1b). In conclusion, HCV is an increasingly common indication for liver transplantation. Alcohol and hepatitis B were frequently occurring cofactors in the referral cohort. Most patients referred were male, although the reason why is not clear. Transplantation offers a good medium-term outcome, despite the high incidence of HCV-associated graft dysfunction.

The relationship of histology to genotype in chronic HCV infection

The histological description of chronic hepatitis is undergoing considerable change at present. It has become important to define chronic hepatitis aetiologically and then define levels of necro-inflammatory change (grade) and fibrosis (stage). The aim of this study was to compare the ability of different histological scoring systems to detect differences in the pathological changes associated with infection with the different HCV genotypes that are known to have different natural histories. The histological appearances of liver biopsies from 29 HCV infected patients were compared by the Knodell histological activity index (HAI), modified histological activity index and the Scheuer histological scoring system. HCV genotyping was performed for each patient by sequence analysis of the 5' non-coding region. The histological appearances from HCV 1 infected patients showed a tendency towards more active necro-inflammatory changes when compared with those from HCV 2 or 3 infected patients. The levels of fibrosis were similar for all genotypes. The modified HAI and Scheuer scoring systems detected differences, not revealed by the Knodell system, in the types of inflammatory pathology produced by the different genotypes of HCV. In particular these scoring systems noted significant differences in the component scores of inflammation, in addition to the total inflammatory scores. In conclusion, the recently introduced scoring systems were able to detect differences in liver pathology produced by infection of similar duration with different viral genotypes. As genotype is considered an important determinant of disease progression and response to anti-viral therapy, it is likely that those scoring systems correlating with genotype will yield more useful histological information than those that do not.

Relationship between hepatitis C genotype and severity of recurrent hepatitis C after liver transplantation

BACKGROUND

Recurrence of hepatitis C virus (HCV) infection after liver transplantation is universal, but the relationship between hepatitis C genotype and posttransplant outcome has been controversial. The aim of this study was to assess the relationship between hepatitis C genotype on posttransplant frequency of recurrent hepatitis, histologic severity of recurrence, and progression to cirrhosis.

METHODS

We studied 42 HCV RNA positive patients who received transplants between 1985 and 1994. Sera were tested for HCV RNA and protocol liver biopsies were in obtained the posttransplant period. Biopsies were scored according to the histologic activity index (HAI) and staged in a blinded fashion.

RESULTS

The distribution of hepatitis C genotypes distribution was as follows: 1a, 19 (45%); 1b, 17 (40%); 2b, 3 (7%); and 1 each of 2a, 3a, and 4a. There was histologic evidence of hepatitis in 38 of 42 (90.4%) of patients. Hepatitis C was mild, moderate, or severe (HAI>3) in 38% of grafts and minimal (HAI 0-3) in 62%. Overall HAI scores and histologic stage were higher in the genotype 1b group. Six of 17 (35%) genotype 1b patients had cirrhosis compared with 2 of 25 (8%) in the non-1b genotype group.

CONCLUSIONS

(1) Histologic evidence of recurrent hepatitis C is seen in 90% of liver allografts; (2) Histologic hepatitis C recurs with similar frequency in genotype 1b and non-1b recipients; (3) Genotype 1b is associated with more severe histologic disease recurrence than non-1b genotypes; (4) Genotype 1b appears to be associated with a higher degree of posttransplant fibrosis and cirrhosis than non-1b genotypes.

Rapid and sensitive genotyping of hepatitis C virus by single-strand conformation polymorphism

There is an increasing demand for genotyping hepatitis C virus (HCV) isolates due to the rapidly expanding list of distinct HCV genotypes and the mounting evidence of genotype-specific clinical consequences. We describe an SSCP-based assay for determining genotypes in HCV infections. HCV RNA extracted from serum was amplified by a sensitive nested-PCR assay producing a 287 bp fragment of the conserved 5' non-coding region (NCR) and analysed by non-denaturing polyacrylamide gel electrophoresis. Following empirical optimisation of the SSCP assay we identified distinct conformation polymorphisms (characteristic band patterns) corresponding to types 1a, 1b, 2a, 2b, 2c, 3 and 4 found in the Western Australian population. Seventy-three HCV RNA-positive samples were used to evaluate the SSCP genotyping assay for accuracy and efficiency by comparison with the previously established genotyping methods of manual direct sequencing and dideoxy fingerprinting. SSCP genotyping was in concord with control methods while performing more rapidly and at a fraction of the cost. Moreover, SSCP detected two co-infected samples that were not shown by the control methods. The PCR-SSCP assay provides an accurate and rapid method for genotyping of HCV RNA-positive samples at the 5' NCR by type-specific sequence polymorphisms which is applicable to large-scale screening.

Relation of hepatitis C virus genotypes to risk factors and hepatic disease in Spanish patients

OBJECTIVE: To ascertain the prevalence of hepatitis C virus (HCV) genotypes in Spain and their distribution by risk factors. METHODS: The study covered 216 patients with hepatitis C. Of these, 63 were intravenous drug users (IVDU), 44 had received transfusions, and 30 were hemodialyzed, and in 79 the risk factors were unknown. Antibodies against HCV were detected by second-generation enzyme immunoassay (EIA) and confirmed by immunoblot. HCV RNA presence was investigated by reverse transcription---polymerase chain reaction (RT-PCR), and a reverse hybridization test of the amplifications was used for the genotyping. RESULTS: The most frequently encountered genotypes were 1b (48.1%), 1a (21.3%) and 3a (11.1%). HCV genotypes 1a (42.8%) and 3a (20.6%) were the most prevalent genotypes in IVDU patients, while 1b was the most frequent in patients with unknown risk factors (62.0%), transfused patients (68.1%) and hemodialyzed patients (50.0%). Mixed infections were detected in nine cases (4.1%); three appeared in IVDU patients (4.7% of the total IVDUs), two in transfused patients (4.5%) and four (50%) in patients with unknown risk factors. No statistically significant differences were found in average ages of the IVDU patients with different genotypes. Non-IVDU patients having genotype 3a presented the lowest average age of all. No significant statistical differences were observed in alanine aminotransferase levels among patient groups with different genotypes (p>0.05 in all cases). Subtype 1b was present in six of the seven cases of cirrhosis (85.7%) and in nine of the 18 cases of active chronic hepatitis (50.0%).

Long-term outcome of hepatitis C virus infection after liver transplantation

We analyzed the long-term clinical course of 71 patients with RNA-positive hepatitis C virus (HCV) infection after liver transplantation. Patients with reinfection after transplantation for HCV-related liver disease, or de novo infection at transplantation were followed for up to 12 years. Cumulative survival for patients with HCV infection at 2, 5, and 10 years after transplantation was 67%, 62%, and 62%, respectively. It was not significantly different from that in patients transplanted for other nonmalignant diseases without HCV infection. The main factor determining long-term survival was the presence or absence of hepatocellular carcinoma (HCC) at transplantation. The 5-year survival rate for HCV patients with or without HCC was 35% versus 73%, respectively (P < .05). No deaths because of viral hepatitis of the graft were observed. Deaths in the first year after transplantation were caused by infectious complications, cardiovascular problems, or rejection; deaths after more than 12 months were exclusively because of recurrence of HCC. Biochemical and histological evidence of hepatitis was found in the majority of the patients, only 16% had normal alanine aminotransferase (ALT) values throughout. Twenty-two percent of patients complained of symptoms, with hepatitis C being the cause in 82% of these. Two patients lost their HCV-RNA for prolonged, ongoing periods of time. The severity of the posttransplantation hepatitis was unrelated to age, sex, severity of liver disease before transplantation, cold ischemic time of the graft, duration of the operation, transfusions, the number of rejection episodes, or the long-term immunosuppressive regime. Only initial short-term therapy with interleukin 2 (IL2) receptor antibodies adversely influenced inflammatory activity. Viral genotype did not influence the course of the graft hepatitis in our series. Histology showed inflammation in 88% of the biopsies and signs of fibrosis in 24%. Mean ALT values correlated with inflammation but not with fibrosis in the biopsies. Porto-portal bridging was observed in six patients, one patient developed cirrhosis within 2 years after orthotopic liver transplantation (OLT). We conclude that chronic hepatitis develops in the majority of patients with HCV infection after liver transplantation. Carrier states without significant laboratory abnormalities are observed in approximately 16%, biochemical abnormalities without symptoms are seen in 60%, and symptomatic disease develops in a quarter of the patients. The disease course closely resembles that seen in nontransplanted hepatitis C patients. It is generally mild but little over 10% of patients develop signs of fibrosis of the graft during the first decade.

Morbidity and mortality of recurrent hepatitis C infection after orthotopic liver transplantation

Through molecular virological testing it is now clear that HCV reinfection of the allograft is virtually universal in liver transplant recipients. Although histopathological recurrence of hepatitis C occurs in the majority of patients, it is absent in a substantial minority. To date, no prognostic factors, other than genotype 1b, have been identified that accurately predict these dissimilar outcomes. The natural history of recurrent hepatitis C varies. Historically, it has been regarded as generally benign. However, with increasing numbers of patients transplanted for hepatitis C it is now clear that a subgroup of patients develops severe progressive cholestatic hepatitis associated with allograft failure and death without retransplantation. Within 5 years following OLT, approximately 15-20% of patients progress to chronic active hepatitis and another 15-20% become cirrhotic. A minority of patients develop glomerulopathy or vasculitis, which are often associated with cryoglobulinaemia. The impact of immunosuppressive medications and rejection episodes on histopathological recurrence of progressive hepatitis C remains controversial and requires further studies. Although actuarial survival rates of patients transplanted for hepatitis C differ among transplantation centres, it appears that histopathological recurrence of hepatitis C does have an adverse impact on actuarial survival compared to the survival of patients transplanted for autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis and metabolic liver diseases. When allograft failure develops in patients with recurrent hepatitis C, retransplantation is indicated, even though recent reports indicate that mortality may be increased, especially with concurrent renal insufficiency.

Detection and typing of hepatitis C RNA in liver biopsies and its relation to histopathology

This paper describes the correlation of hepatitis C genotypes detected in liver tissue with histological grading (inflammatory activity) and staging (degree of fibrosis/cirrhosis). The viral genotype was analysed by type-specific polymerase chain reaction (PCR) and correlated with histology and age of patients. In 69 patients with chronic hepatitis C (HCV) infection, genotypes 1a and 1b were detected in 13 (18.8%) and 31 (44.9%) liver biopsies, respectively. Genotypes 2a and 2b were each detected once (1.5%) and 12 (17.4%) tissue samples showed a mixed infection with two genotypes. In 11 (15.9%) biopsies, no genotype could be established. The liver specimens were grouped according to the presence or absence of genotype 1b: group A consisted of specimens infected with genotypes 1a, 2a, and 2b (n = 16), Group B contained biopsies infected with genotype 1b (n = 42), and group C were biopsies with no detectable genotype (n = 11). Activity (grade) of chronic hepatitis was not different in these three groups. However, advanced fibrosis/cirrhosis was observed in 16 (38.1%) biopsies in group B (containing genotype 1b), compared with none in group A (P = 0.01). The mean age of patients in group B was significantly higher than that in group A (P = 0.038), and the mean age of patients with advanced fibrosis was higher than that of patients with low fibrosis scores within these two groups (P = 0.004). Stepwise logistic regression revealed an independent association of age and genotype 1b (group B) with advanced fibrosis/cirrhosis. These data indicate that patients infected with genotype 1b have an higher risk of developing cirrhosis than do patients with other genotypes.

Interferon-alpha therapy for chronic hepatitis C in special patient populations

Interferon-alpha therapy for chronic hepatitis C in special patient populations raises a number of issues. Patients with hemophilia, kidney disease requiring hemodialysis, mixed cryoglobulinemia, HIV infection, and those receiving an allograft share some characteristics that complicate the treatment of hepatitis C virus infections. These patients generally have some degree of immune deficiency, higher levels of hepatitis C virus replication, and are infected with genotypes 1a or 1b. Each of these characteristics is often associated with a poor response to interferon therapy. Clinical research in this area also has been limited. Current data and clinical experience demonstrate that interferon-alpha therapy should be considered in patients with hemophilia who have concurrent hepatitis C viral infection. Other hepatitis C virus-infected patient populations in which interferon-alpha therapy may be beneficial include those undergoing hemodialysis, mixed cryoglobulinemia, or HIV infection. Further, the high incidence of relapse following treatment cessation in these patients warrants prolonged administration of interferon-alpha. Patients undergoing renal or hepatic allograft transplantation who develop hepatitis C virus infections are not as likely to benefit from interferon-alpha therapy. These patients may be at risk for allograft rejection during interferon treatment.

Hepatitis C virus: molecular biology and genetic variability

The pathogenetic mechanisms of hepatitis C virus (HCV) infection are poorly known. An understanding of HCV biology and the potential clinical impact of HCV genetic variability is essential to managing, treating, and preventing HCV infections. HCV is a member of the Flaviviridae viral family. Its genome is a positive, single-strand RNA molecule. The structure of the HCV particles is poorly known due to the lack of an efficient cell culture system as well as a striking heterogeneity in density. The core protein may have a regulatory role on both viral and cellular gene expression. The mechanisms of HCV-RNA replication may include synthesis of negative strand intermediates, which drive synthesis of new positive RNA genomes. New procedures have been developed to better identify and characterize the HCV-RNA genome. The mechanisms of HCV persistence are currently unknown, although it is known that HCV chronicity develops despite humoral and cellular responses to HCV proteins. HCV-RNA shows significant genetic variability with an estimated rate of nucleotide change of approximately 10(-3) substitutions/site/year. Currently, three major HCV genotypes and three to seven minor subtypes can be distinguished. The geographical distribution of these genotypes and subtypes varies significantly. It appears that poor clinical response to interferon (IFN) is more common with HCV genotype 1. In addition, some studies have shown an association between chronic infection, severe chronic hepatitis, and cirrhosis with subtype 1b. Further, there is evidence for a potential direct effect of HCV in liver carcinogenesis, with subtype 1b possibly being an independent risk factor for hepatic carcinoma development. HCV-RNA circulates as a population of RNA molecules, which creates a heterogeneity referred to as "quasispecies." It is possible that some HCV strains might have direct clinical implications. It may be that highly heterogeneous populations observed prior to treatment might correlate with a lower rate of response to IFN therapy.

Phylogenetic analysis of hepatitis C virus isolates and their correlation to viremia, liver function tests, and histology

Nucleotide sequence analysis of hepatitis C virus (HCV) strains showed substantial variability leading to a classification into several genotypes and subtypes. The data correlating HCV genotypes and subtypes with hepatitis C viremia levels, demographic characteristics of patients (age, mode of transmission, duration of infection), and severity of liver disease are conflicting. The interpretation of several studies is further complicated because the molecular methods used lacked specificity for genotyping/subtyping and underestimated viremia levels, especially in patients infected with HCV genotypes 2 and 3. In the present study we investigated 97 consecutive patients with chronic hepatitis C using molecular "gold standard" methods. HCV subtyping was performed by sequence and phylogenetic analysis of the nonstructural (NS)-5 region and serum HCV-RNA concentration was assessed by a validated genotype-independent quantitative reverse-transcription-polymerase chain reaction assay using an internal RNA standard. Patients infected with subtypes HCV-1b, HCV-2a-c, and HCV-4 were older than patients infected with HCV-1a and HCV-3a. Serum HCV-RNA levels ranged from 1.5 x 10(4) to 1.0 x 10(8) copies/mL with no significant differences between median serum HCV-RNA concentrations in patients infected with different genotypes/subtypes. Although patients infected with HCV-1b were older, no biochemical or histological evidence was obtained that this subtype is associated with more severe liver disease. Furthermore, the present study showed a lack of correlation between the serum HCV-RNA concentration, biochemical parameters, and liver histology. The median serum HCV-RNA levels in patients with chronic persistent hepatitis, chronic active hepatitis, and liver cirrhosis were 5.0 x 10(6) copies/mL, 2.5 x 10(6) copies/mL, and 5.0 x 10(6) copies/mL, respectively. These differences were not significant. In conclusion, using optimized and validated molecular techniques, the present cross-sectional study showed no correlation between HCV genotypes/subtypes, viremia, liver function test results, and histology.

Hepatitis C virus 1b is the dominant genotype in HCV-related carcinogenesis: a case-control study

In an ongoing case-control study in Athens on the etiology of hepatocellular carcinoma (HCC), an analysis was made in order to assess whether HCV genotype 1b is associated with hepatocellular carcinoma (HCC). The HCV genotype was determined in 17 HCC patients, 87 patients with chronic hepatitis C (CHC) without cirrhosis (NC-CHC) and 23 patients with CHC and cirrhosis (C-CHC). HCV genotype 1b was detected in 14/17, 16/23 and 23/87 of HCC, C-CHC and NC-CHC respectively. The age- and gender-adjusted odds ratios contrasting HCC with NC-CHC and C-CHC with NC-CHC were 8.3 and 3.8 respectively. These data strongly support the hypothesis that HCV 1b is a stronger liver carcinogen than other HCV genotypes, probably through increased HCV replication and enhanced liver cytopathicity.

Hepatitis C virus and organ transplantation

Hepatitis C virus (HCV) is both the leading cause of cirrhosis and hepatic failure leading to liver transplantation and a cause of chronic hepatitis in approximately 10% of all transplant recipients. Beginning 5-10 years or more posttransplant, HCV causes progressive liver disease in a significant fraction of infected individuals and contributes to an increased incidence of opportunistic infection and hepatocellular carcinoma. The existence of multiple genotypes of HCV with differing biologic behaviors and the generation of antigenic diversity of the virus (quasispecies) during the course of infection, limit the capacity of the immune system to generate protective immunity. Antiviral therapy with interferon-alpha is effective in only a minority of transplant patients, and since allografts from HCV infected donors are quite efficient in transmitting the virus, great attention is paid to the appropriate use of organs from HCV-positive donors. At present, these organs should be particularly targeted for patients in emergent need of lifesaving heart, liver, or lung transplants. Issues requiring further investigation include the impact of viral superinfection on HCV-infected recipients of organs from HCV-infected donors and the use of such organs in seronegative patients who are older, diabetic, or highly sensitized, for whom quality of life issues may outweigh the long-term impact of HCV infection.

Heterogeneity of hepatitis C virus

A great deal of information on the molecular heterogeneity of hepatitis C virus (HCV) has been achieved since its discovery in 1989. However, little is known about the clinical significance of these variations. Based on the degree of sequence variation, HCV has been classified into six major groups or types, differing by 31-34% at the nucleotide level over the entire virus genome. Each type is divided into several subtypes that differ by 20-23% in nucleotide sequence. Viruses within the same subtype are up to 10% divergent and, within infected individuals, vary by up to 1.5%. Genotype distributions are not homogeneous around the world and may reflect both historical and recent parenteral routes of transmission. The clinical implication of these genomic variations are not yet fully elucidated: genotype 1b has been associated with end-stage liver disease, including liver cirrhosis and hepatocellular carcinoma, but this finding might rather reflect its earlier introduction to the populations studied. Consistent evidence exists that types 2 and 3 have a higher response rate to interferon treatment than type 1, although the interplay between genotype and viral load in determining the response is still unclear. Immunohistochemical studies indicate a stronger activation of the endogenous interferon system in the liver of patients infected with type 1 compared to those infected with types 2 and 3, explaining, at least in part, its low responsiveness to exogenous interferon treatment. Biological, sequence-dependent variations of genotypes have been poorly investigated to date, but differential efficiency of translation activity of the 5' non-coding region has been reported. The availability of "in vitro" systems for evaluating pathogenetic aspects and neutralization mechanisms will improve the present knowledge on this world-wide infectious disease and on the clinical usefulness of distinguishing between genotypes.

Hepatitis B and C viruses and primary liver cancer

The data presented indicate that viral agents (namely, HBV and HCV) are major environmental aetiological factors for human primary liver cancer. It is important to elucidate the molecular mechanisms further because HCC is one of the few examples of virus-related human cancers. In addition, the available evidence points to the possibility of at least partial prevention of the tumour by large-scale vaccination.

Histologic progression of recurrent hepatitis C in liver transplant allografts

The incidence and severity of recurrent hepatitis C virus (HCV) infection in liver transplant recipients vary widely, and the long-term sequelae of recurrent infection are not known. To better define the biology of recurrent HCV in liver transplant patients, we reviewed the histology of recurrent HCV in serial biopsies of 19 patients with pretransplant polymerase chain reaction (PCR) evidence of HCV infection. All posttransplant (post-TX) biopsies (n = 81) were reviewed, and RNA was extracted from at least one paraffin-embedded biopsy from each patient. RNA was analyzed for HCV by nested, reverse transcription-PCR (RT-PCR) using primers for the 5' non-coding region of HCV as well as for albumin (as an internal control). All post-TX biopsies tested (12-1,677 days post-TX) were positive for HCV RNA by RT-PCR, while normal control biopsies were negative. Fifteen of 19 patients developed recurrent chronic hepatitis typical of HCV. Many of these patients showed a progression from early biopsies with acute lobular hepatitis to later biopsies with chronic hepatitis with portal lymphoid aggregates. An acute lobular hepatitis typified by sinusoidal lymphocytosis, acidophil bodies, and lobular disarray was seen an average of 135 days post-TX, with a range of 39-279 days. The time post-TX between this and earlier non-hepatitis biopsies was significantly different (p < 0.0004, Student's t test). Chronic hepatitis with portal lymphoid aggregates was seen an average of 356 days post-TX, with a range of 89-1,365 days. The time post-TX was significantly longer than for acute lobular hepatitis (p < 0.03, Student's t test). Fifty-three percent of HCV TX patients progressed from acute lobular hepatitis to chronic hepatitis with lymphoid aggregates within 1 year of TX, and 79% showed these changes within 4 years. Six patients had progressive fibrosis; one die of liver failure and two became cirrhotic. Recurrent HCV appears to progress from an acute lobular hepatitis to chronic hepatitis with lymphoid aggregates in the majority of patients. Significant scarring occurred in 32% of patients and 16% developed end-stage liver disease from recurrent HCV. These later findings suggest that the long-term course of recurrent HCV in liver allografts may not be as indolent as first thought.

Hepatitis C virus genotypes, hepatitis, and hepatitis C virus recurrence after liver transplantation

Several genotypes of hepatitis C virus (HCV) have been recently identified by phylogenetic analysis, but their clinical relevance in the liver transplant setting is unknown. We evaluated the incidence and course of recurrent hepatitis C after transplantation in 50 patients who underwent transplantation for HCV-related liver disease. Liver biopsy specimens were obtained when clinically indicated and at yearly intervals; hepatitis was histologically graded and staged according to standard criteria. HCV-RNA was detected by nested reverse-transcription polymerase chain reaction (RT-PCR). HCV genotyping was performed by primer specific PCR. Follow-up was 6 to 62 months. HCV genotype distribution after transplantation of our 50 patients was as follows: 31 type 1b, 13 type 2a, 3 type 1a, 1 type 3a, 1 type 1b/2a, and 1, undetermined. Actuarial rates of recurrent hepatitis and of severe fibrosis or cirrhosis 5 years after transplantation were 56% and 20%, respectively, in patients infected by type 1b and 33% (P = .18) and 8% (P = .16) in those infected by 2a. In conclusion, this study provides evidence that in patients infected by HCV type 1b there is a trend for a more aggressive recurrent liver disease.

Long-term outcome of hepatitis C infection after liver transplantation

BACKGROUND

End-stage cirrhosis related to hepatitic C virus (HCV) is a common reason for liver transplantation, although viremia ia known to persist in most cases. We investigated the impact of persistent HCV infection after liver transplantation on patient and graft survival and the effects of the HCV genotype and the degree of HLA matching between donor and recipient on the severity of recurrent hepatitis.

METHODS

A group of 149 patients with HCV infection who received liver transplants between January 1982 and April 1994 were followed for a median of 36 months; 623 patients without HCV infection who underwent liver transplantation for end-stage chronic liver disease were used as a control group. A total of 528 liver-biopsy specimens from the HCV-infected recipients were reviewed, including 82 obtained one year after transplantation as scheduled and 39 obtained at five years as scheduled. In addition, biopsy specimens were obtained from 91 of the HCV-negative patients five years after transplantation.

RESULTS

Cumulative survival rates for the 149 patients with HCV infection were 79 percent after one year, 74 percent after three years, and 70 percent after five years, as compared with rates of 75 percent, 71 percent, and 69 percent, respectively, in the HCV-negative transplant recipients (P=0.12). Of the 130 patients with hepatitis C infection who survived more than 6 months after transplantation, 15 (12 percent) had no evidence of chronic hepatitis on their most recent liver biopsy (median followup, 20 months), 70 (54 percent) had mild chronic hepatitis (median, 35 months), 35 (27 percent) had moderate chronic hepatitis (median, 35 months), and 10 (8 percent) had cirrhosis (median, 51 months). Graft loss occurred after a median of 303 days in 27 of the 149 patients, including 5 with HCV-related cirrhosis and 3 with HCV-related cholestatic hepatitis. Infection with HCV genotype 1b was associated with more severe graft injury, whereas the primary immunosuppressive regimen used and the extent of HLA mismatching between donors and recipients had no significant effect on this variable.

CONCLUSIONS

After liver transplantation for HCV-related cirrhosis, persistent HCV infection can cause severe graft damage, and such damage is more frequent in patients infected with HCV genotype 1b than with other genotypes. After five years, the rates of graft and overall survival are similar between patients with and those without HCV infection.

Hepatitis C virus: biological and clinical consequences of genetic heterogeneity

Hepatitis C Virus infection accounts for the majority of post-transfusion and sporadic hepatitis. In Western Europe, anti-HCV is detected in 0.4-1.5% of healthy blood donors. There is a high frequency of progressive chronic hepatitis, ranging from 50 to 80%, which leads to cirrhosis in 20-50% of patients after 10-20 years. Viremic patients with minimal biochemical abnormalities may have chronic liver disease histologically. There is growing evidence that virological features of HCV are associated with different clinical manifestations and response to therapy. The RNA genome consists of a 5' and 3' Untranslated Region, a structural domain encoding the core and envelope proteins, and a non-structural domain. Different HCV isolates show a high sequence heterogeneity, which has led to the classification of currently six genotypes and several subtypes. There is a marked difference in the geographic distribution of HCV genotypes, with types 1, 2 and 3a being most frequently found in western countries. In The Netherlands, subtype 1b accounts for approximately 60% of all cases of chronic HCV. Serologic diagnosis based on recombinant C-100 antigens (first generation immunoassays) only reliably detected type 1, due to the heterogeneity of the NS4 region; inclusion of more conserved proteins c22 and c33 (second generation assays) has largely improved sensitivity of anti-HCV testing. Genotype 1b is associated with more severe liver disease and with lower response rates for antiviral therapy, compared with types 2 and 3. Quasispecies nature and escape mutants may enable viral persistence and the development of chronic liver disease. As cross-reactivity between genotypes is unlikely, prevention of HCV disease may be dependent on the development of multivalent vaccines.