Clinical usefulness of an assay for hepatitis C virus core in the diagnosis of non-A, non-B hepatitis and monitoring of the response to interferon therapy

Lymphocyte T helper-specific reactivity in sustained responders to interferon and ribavirin with negativation (seroreversion) of anti-hepatitis C virus

BACKGROUND

Seroreversion, negativation of anti-hepatitis C virus previously positive, is sometimes found in some chronic hepatitis C-sustained responders (SRs) to antiviral therapy.

AIMS

To determine the probability of seroreversion in SR treatment with Interferon and Ribavirin, and lymphocyte T helper (CD4+) reactivity to HCV antigens.

METHODS

Thirty SR were followed on average for 54.8 months. Anti-HCV was tested by third generation test. Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood and cultured to evaluate CD4+ proliferation in response to 2 microg/ml of eight HCV recombinant antigens from core, NS3, NS4, NS5 regions.

RESULTS

Seroreversion was verified in 23% of patients (7/30), appearing at 47.5+/-24.0 months. The probability of anti-HCV loss in this group was 25% at 56 months after ending therapy. In 57% (4/7), anti-HCV returned to positive. These 7 SR patients with seroreversion also showed weaker CD4+ reactivity in 5% of tests (3/56) than the remaining 23 anti-HCV-positive SRs who showed stronger reactivity in 18% of tests (33/184), P=0.036.

CONCLUSIONS

One-quarter of the SR showed seroreversion of anti-HCV and weaker CD4+ specific HCV proliferation than those who remained anti-HCV positive. The data suggest that complete viral eradication is a possible and achievable clinical objective.

IgG1 anti-P2 as a marker of response to interferon in patients with chronic hepatitis C

To study the relations of antibody production to long-term outcomes after interferon (IFN) treatment in patients with chronic hepatitis C (CH-C), we used ELISA to measure the levels of antibodies against HCV core protein and peptides. Samples from 21 complete responders and 36 non-responders were collected before IFN therapy, soon after the end of IFN therapy and 6 months later. Using a set of 19 synthesized HCV core peptide antigens, we found that anti-P2 (11-25a.a.) was the most prevalent of all IgG antibodies (93%: 39/42). Among complete responders, IgG1 anti-P2 levels had fallen by the end of IFN therapy (from 79.8 +/- 60.4-46.1 +/- 44.2: P < 0.01), and were lower still 6 months after the end of IFN therapy (31.0 +/- 35.2: P < 0.001); this change was the greatest of all antibodies studied. Among the non-responders, there was no change within the follow-up period. Soon after the end of IFN therapy, IgG1 anti-P2 levels were more than 30% lower than the initial value in more than two-thirds of the complete responders, but in only one-third of the non-responders (14/20 vs. 8/25: P < 0.05). Six months after the end of IFN therapy, IgG1 anti-P2 levels were more than 30% lower than the initial value in more than 85% of the complete responders, but in only 12% of the non-responders (17/20 vs. 3/25: P < 0.001). In conclusion, the changes in levels of IgG1 anti-P2 paralleled the activity of chronic hepatitis C after IFN therapy, and IgG1 anti-P2 levels may be markers of the efficacy of IFN therapy.

Interferon therapy reduces the risk for hepatocellular carcinoma: national surveillance program of cirrhotic and noncirrhotic patients with chronic hepatitis C in Japan. IHIT Study Group. Inhibition of Hepatocarcinogenesis by Interferon Therapy

BACKGROUND

Previous studies on the effect of interferon therapy on the incidence of hepatocellular carcinoma have not sufficiently assessed degree of liver fibrosis, a major risk factor for hepatocellular carcinoma.

OBJECTIVE

To evaluate the effect of interferon therapy on incidence of hepatocellular carcinoma, adjusting for risk factors, including the degree of liver fibrosis.

DESIGN

Retrospective cohort study.

SETTING

Seven university hospitals and one regional core hospital in Japan.

PATIENTS

2890 patients with chronic hepatitis C who had undergone liver biopsy since 1986. Of these patients, 2400 received interferon and 490 were untreated.

MEASUREMENTS

The degree of liver fibrosis was assessed from stage F0 (no fibrosis) to stage F4 (cirrhosis). Response to interferon was determined virologically and biochemically. Screening for development of hepatocellular carcinoma was performed periodically during an average follow-up of 4.3 years. Effect of interferon therapy on the risk for hepatocellular carcinoma was analyzed by using Cox proportional hazards regression.

RESULTS

Hepatocellular carcinoma developed in 89 interferon-treated patients and in 59 untreated patients. Among untreated patients, the annual incidence of hepatocellular carcinoma increased with the degree of liver fibrosis, from 0.5% among patients with stage F0 or F1 fibrosis to 7.9% among patients with stage F4 fibrosis. The cumulative incidence in treated and untreated patients differed significantly for patients with stage F2 fibrosis (P = 0.0128) and for those with stage F3 fibrosis (P = 0.0011). In multivariate analysis, interferon therapy was associated with a reduced risk for hepatocellular carcinoma (adjusted risk ratio, 0.516 [95% CI, 0.358 to 0.742]; P < 0.001), especially among patients with sustained virologic response (risk ratio, 0.197 [CI, 0.099 to 0.392]), among those with persistently normal serum alanine aminotransferase levels (risk ratio, 0.197 [CI, 0.104 to 0.375]), and among those with alanine aminotransferase levels less than two times the upper limit of normal (risk ratio, 0.358 [CI, 0.206 to 0.622]).

CONCLUSIONS

Interferon therapy significantly reducesthe risk for hepatocellular carcinoma, especially among virologic or biochemical responders.

An ELISA for the detection of antibody to the core antigen of hepatitis C virus: use in diagnosis and analysis of indeterminate samples

AIMS

In order to examine more carefully the natural history of hepatitis C virus infection and to determine a role for anti-core in the discrimination of indeterminate samples, a solid phase ELISA to detect antibody of the immunoglobulin G class to the hepatitis C virus core antigen was developed using purified protein expressed in Escherichia coli from a major portion of the core antigen coding region.

METHODS/RESULTS

In a study which examined 651 samples submitted for routine testing by a commercial ELISA (Ortho), only 11 samples showed discrepant results; of these, 10 were Ortho ELISA positive, anti-core negative and one was Ortho ELISA negative anticore positive. Supplemental tests showed that 5/10 of these samples were anti-HCV negative by RIBA and the reciprocal 5 were negative for anti-C22 but positive for anti-C100 and anti-C33. The Ortho ELISA negative, anticore positive sample was weakly positive for anti-C22. The anti-core ELISA was then used to examine 67 indeterminate samples from the blood bank; 11/11 samples which were HCV-RNA positive were anti-core positive and 7/56 samples which were HCV-RNA negative were anti-core positive. The anti-core titre was then examined in two groups of indeterminate samples; group 1, polymerase chain reaction-positive, anti-core positive and group 2, polymerase chain reaction-negative, anti-core positive. The geometric mean anti-core titres in these groups were 1 x 10(-3.6) and 1 x 10(-2.3), respectively. Thus in this group of indeterminate samples, all samples (except one) with an anti-core titre > or = 1/200 were polymerase chain reaction-positive, confirming a close correlation between anti-core levels and hepatitis C viraemia. Anti-core was detected with equal efficiency in patients infected with genotypes which differed to that used to express the recombinant core antigen.

Quantitation of anti-hepatitic C virus antibodies in interferon-treated patients by S29-1/S4 ELISA

In 23 patients with chronic hepatitis C who have undergone interferon (IFN) treatment, quantitation of anti-hepatitis C virus IgG antibodies by a second-generation assay S29-1/S4 ELISA [Sato et al. (1993): Microbiology and Immunology 37: 295-304]. (anti-S29-1/S4) was compared with that of anti-HCV core IgG antibodies (C22-3, anticore) and the presence of viral RNA confirmed by the reverse transcription-nested polymerase chain reaction (RT-nested PCR). In 12 complete responders with loss of HCV-RNA and normal alanine aminotransferase (ALT) levels at 6 months after therapy, IgG antibodies quantified by a second-generation assay have decreased significantly at the end of treatment (P < 0.05). Further significant reduction of anti-S29-1/S4 titers was observed at 6 months after therapy (P < 0.01) as well as anti-core antibodies (P < 0.01). On the other hand, in 11 non-responders with persistent or intermittent viremia at 6 months after therapy, no significant change in the level of anti-S29-1/S4 titers was observed, whereas anti-core titers have decreased at the end of therapy (P < 0.01). In contrast, both levels of anti-S29-1/S4 and anti-core have increased at 6 months after treatment (P < 0.05). It is concluded that, although it appears difficult to monitor the effect of virus clearance during IFN therapy, changes in anti-S29-1/S4 titers after IFN treatment correlate with virus clearance and with anti-core titers.

Clinical study of IgA antibody against hepatitis C virus core antigen in patients with type C chronic liver disease

Immunoglobulin A class antibody to hepatitis C virus core antigen (IgA anti-HCc) was measured in the serum of 128 patients with type C chronic liver disease. Fifty-eight patients (45.3%) were seropositive. IgA anti-HCc was detected in only one of 20 patients with chronic persistent hepatitis; however, 52.3% (46/88) of patients with chronic active hepatitis and 55% (11/20) of patients with liver cirrhosis were seropositive. Histological examination revealed that 22 (71.0%) of 31 patients with severe disease activity were seropositive compared to 35 (44.9%) of 78 patients with moderate (P < 0.05) and one (5.3%) of 19 patients with mild (P < 0.01) histological changes. IgA anti-HCc was measured sequentially in 65 patients who underwent interferon therapy. There was a significant difference between responders and other patients in the mean ratio of IgA anti-HCc titers one month after therapy. Three months after therapy, IgA anti-HCc was detectable in only two of 15 responders who were IgA anti-HCc seropositive at the start of therapy. In contrast, IgA anti-HCc reappeared three months after therapy despite a temporary decrease to undetectable levels in all nonresponders. We conclude that IgA anti-HCc is a useful marker to identify the presence of active type C liver disease and that the disappearance of IgA anti-HCc three months after interferon therapy predicts a good response in treated patients.