Long-term observation of HCV-positive patients with normal ALT values: persistence of a clinically healthy state

Review article: management of patients with chronic hepatitis C virus infection and "normal" alanine aminotransferase activity

BACKGROUND

Hepatitis C virus infection, a major cause of chronic liver disease, occurs with normal serum alanine aminotransferase activity in approximately 25% of patients. These patients have historically remained untreated but substantial evidence indicates liver damage, progression of disease and impaired quality of life in some individuals.

AIM

To review the current management of patients with chronic hepatitis C and normal alanine aminotransferase activity.

METHODS

This review represents the summary of discussions at a Clinical Workshop with a comprehensive literature searching of available databases (PubMed and Embase).

RESULTS

Current limits defining normal serum alanine aminotransferase activity are not representative of a "healthy" status. Most patients with hepatitis C and normal alanine aminotransferase levels have histologically proven liver damage that, although generally mild, may be significant (> or =F2) in up to 20% of patients and progresses at approximately 50% of the rate in patients with elevated alanine aminotransferase levels. Some patients have persistently normal alanine aminotransferase activity and may have a more benign outcome, but a significant proportion (> or =20%) experience periods of increased serum alanine aminotransferase activity which may be associated with enhanced disease progression.

CONCLUSIONS

A treatment approach that considers host and virus-related variables and optimizes patient and cost benefits may therefore provide more effective management of patients with chronic hepatitis C and normal alanine aminotransferase activity.

A cost-effective algorithm for the diagnosis of Hepatitis C virus infection and prediction of HCV viremia in Cameroon

Conventional tests for antibody to Hepatitis C virus (HCV) and HCV RNA require considerable time before results are available, remain very expensive and are not adapted to many sub-Saharan African countries where HCV is endemic. The aim of this study was to evaluate the accuracy of an algorithm consisting of two HCV rapid tests to diagnose and predict HCV viremia in patients in Cameroon. Three hundred and twenty nine plasma samples were screened by two HCV rapid tests (ImmunoComb II HCV, PBS Orgenics and Hexagon HCV, Human). Previous evaluation of these samples for HCV antibodies (anti-HCV) by conventional third generation ELISA, considered as a reference test, indicated that 168 were anti-HCV negative and 161 positive. Among the 161 anti-HCV positive plasma, 114 (71%) were HCV RNA-positive by RT-PCR assay. The ImmunoComb II HCV test provided the more sensitive detection of anti-HCV (sensitivity: 99.4% with a 95% CI = 96-100%). Surprisingly, the second HCV rapid test, Hexagon HCV, showed a high capacity to identify non-viremic subjects amongst anti-HCV positive cases (93.6% [95% CI: 82-99%]). These results suggest an algorithm using ImmunoComb II HCV as a first test to screen anti-HCV positive subjects, and Hexagon HCV as a second test to discriminate between viremic and non-viremic HCV seropositive subjects.

Quantitative signal of anti-HCV by an automated assay predicts viremia in a population at high prevalence of hepatitis C virus infection

BACKGROUND AND AIMS

The diagnosis of ongoing hepatitis C virus (HCV) infection involves the detection of specific antibodies and of HCV-RNA. We aimed to assess the relationship between these two parameters in a representative sample of a population at high risk for HCV infection.

METHODS

Plasma and serum samples were respectively tested for HCV-RNA by a qualitative PCR (Cobas Amplicor HCV, Roche) and for HCV antibodies by a MEIA screening assay (AxSYM HCV 3.0, Abbott) and an immunoblot (Inno-LIA-III, Innogenetics).

RESULTS AND CONCLUSIONS

Out of 888 samples assayed, 579 (65.2%) were positive for HCV-RNA, while anti-HCV antibodies were detected respectively in 802 sera by AxSYM (90.3%) and in 783 by LIA (706 positive and 77 indeterminate, 88.2%). The anti-core antibodies displayed the best correlation with viremia, since they were present in 97.1% of the PCR+ samples, followed by anti-NS3 (90.2%) and anti-NS4 (89.6%). Only one HCV-RNA positive sample was negative by LIA and MEIA (early seroconversion). The AxSYM sample/cutoff (S/CO) values were directly correlated with the presence of HCV-RNA: a PCR positivity was found in 4.9% of samples with a S/CO < or =10, in 60.8% of samples with a S/CO between 11 and 50 and in 93.6% of cases with a S/CO >50, (P < 0.005). The immunoblot adds little, on a single specimen, to the information yielded by the AxSYM screening test. A suitable diagnostic algorithm for HCV in high-risk settings could be the anti-HCV screening by MEIA and a qualitative assay for HCV-RNA on samples with low reactivity.

Clinical management of HCV carriers with normal aminotransferase levels

An ad hoc committee appointed by the Italian Association for the Study of the Liver (AISF) proposed these Practice Guidelines for the management of HCV carriers with persistently normal aminotransferase levels. Only stringent ALT determinations will make it possible to distinguish these subjects from those in temporary biochemical remission. The overall prevalence in Italy has been estimated between 1.5 and 10.6%. HCV RNA quantitation and genotype determination are not predictors of the presence and severity of liver damage nor correlate with the outcome of the disease, and should not be used in clinical practice for the management and surveillance of HCV carriers with normal ALT. Only a minority of HCV carriers with normal ALT levels show a normal morphological picture (true 'healthy carriers'). Disease activity is mild in most cases; fibrosis is generally mild and cirrhosis is very rare. Histological activity, as monitored by sequential liver biopsies, seems to have very slow evolution. HCV carriers should not undergo liver biopsy on a routine basis. Liver biopsy can be reasonably proposed only in selected cases. Until the results of studies with PEG interferon plus ribavirin are available, HCV carriers should not receive antiviral treatment outside controlled experimental studies.

Hepatitis C virus carriers with persistently normal aminotransferase levels: healthy people or true patients?

Since the discovery of hepatitis C virus, the availability of serological hepatitis C virus screening has led to the identification of many subjects with normal aminotransferase levels who are chronically infected by the hepatitis C virus. To date, the epidemiology and natural history of subjects with normal aminotransferase levels are far from being clarified. Further, whether subjects with persistently normal aminotransferase levels should routinely undergo liver biopsy is still extremely controversial, and benefit from interferon treatment in this group of patients is yet to be proven. On account of the consistent normality of aminotransferases, it is not easy to calculate the rate of persons with normal aminotransferase levels among chronic hepatitis C virus carriers, nor their prevalence in the general population. It has been estimated that up to 25% of patients with chronic hepatitis C virus infection have persistently normal aminotransferase levels (10% to 40%, according to different studies). Most studies showed a clear prevalence of females, ranging from 58% to 90%. Liver biopsy shows some degree of chronic liver disease in up to 80% of these subjects, although in the majority, histological damage is mild and probably does not progress to more severe liver disease, moreover, the progression to fibrosis is slower than in patients with elevated aminotransferase levels. Virological features of these subjects (hepatitis C virus genotype distribution, viral load, quasispecies diversity) do not differ with respect to patients with elevated aminotransferase levels although a higher frequency of non 1 hepatitis C virus types has been reported. To date, no biochemical or virological tools to assess the presence and severity of liver damage exist. Antiviral treatment with interferon may induce a long-term response in only a small proportion of hepatitis C virus carriers with persistently normal aminotransferase levels, and many patients develop aminotransferase-flare-up during or shortly after treatment. Thus, interferon or combination antiviral treatment of hepatitis C virus carriers with normal aminotransferase values should be avoided in clinical practice.

Subjects positive for hepatitis C virus RNA with normal aminotransferase levels, a "trompe l'oeil" clinical picture?

BACKGROUND

Quite often subjects affected by chronic hepatitis C virus infection have no clinical signs of liver disease and serum aminotransferase values never go beyond the upper limit of normal. Yet these subjects, defined "asymptomatic HCV carriers", often have active viral replication and various degrees of histological damage.

AIMS

To verify, in a population of antibody to hepatitis C virus carriers, if normal serum aminotransferase values in hepatitis C virus-RNA positive differed considerably from those in hepatitis C virus-RNA negative subjects.

SUBJECTS/METHODS

We followed 24 anti-hepatitis C virus-positive subjects (15 hepatitis C virus-RNA positive and 9 negative) by measuring alanine and aspartate aminotransferase levels at 3-month intervals for a median of 40 months (range 6-77).

RESULTS

Determinations resulted repeatedly and rigorously within the normal range in all participants. Alanine aminotransferase values were higher in hepatitis C virus-RNA positives than in negatives (mean +/- SD: 0.609+/-0.172 vs 0.434+/-0.153 times the upper limit of normal; p<O.001). Aspartate aminotransferase values in both groups reflected the same consistent difference (mean +/- SD: 0.652+/-0.170 vs 0.528+/-0.151 times the upper limit of normal, p<0.001).

CONCLUSIONS

Our findings demonstrate that biochemical activity exists in asymptomatic hepatitis C virus-RNA-positive carriers, but it is so slight that serum aminotransferase levels do not go beyond the upper limit of normal. With the prevailing range of normality, serum aminotransferase determination is a helpful but not reliable marker of disease activity in chronic hepatitis C virus infection. The normal range for aminotransferases needs to be redefined in order to set up a more accurate diagnostic profile of subjects with chronic hepatitis C virus infection.

Characteristics of hepatitis C viral genome associated with disease progression

The clinical presentations of chronic hepatitis C are not uniform. Some patients show persistently high serum alanine transaminase (ALT) values and develop liver cirrhosis and hepatocellular carcinoma (HCC), whereas serum ALT values stay normal in other patients. The mechanism causing this diversity remains to be elucidated. The aim of this study was to identify genomic characteristics of hepatitis C virus (HCV) genotype 1b associated with disease progression. Full length sequences of HCV were determined in 14 patients who showed persistently normal serum ALT values (normal ALT group) and 13 cirrhotics with HCC (HCC group). Residues in which amino acid usage was different between these 2 groups were extracted, and Progression score was defined as the total number of residues with 7 amino acids, more frequently present in the HCC group than in the normal ALT group. In the validation of this Progression score in 9 patients with normal ALT and 25 with HCC, the score was significantly higher in the HCC group (3.1 +/- 1.1 vs. 2.0 +/- 0.9, P =.019). Finally, the correlation between the score and clinical markers related to disease progression was analyzed. In a total of 107 patients with chronic HCV infection, the Progression score was correlated significantly with platelet counts (r = -0.31, P =.0024) by multivariate analysis. In conclusion, high Progression scores were associated with the presence of HCC and low platelet counts. Sequences of the HCV-1b genome may be related to the progression of chronic hepatitis C.