Therapeutic efficacy of interferon on HCV-RNA in chronic hepatitis C

Changes in serum levels of hepatitis C virus genotype 1b monitored by real-time quantitative polymerase chain reaction as a predictor of long term response to interferon-alpha treatment

OBJECTIVE

The aim of this study was to find whether there is a relationship between the changes in the amounts of hepatitis C virus (HCV) at the start of interferon treatment and the long term response to therapy.

METHODS

In 20 patients with HCV genotype 1b each given 880 MU of interferon-alpha, the changes in serum HCV RNA during the first 2 wk of therapy were monitored by real-time quantitative polymerase chain reaction (PCR).

RESULTS

Real-time quantitative PCR detected HCV RNA at 10(1)-10(8) copies/ml. Serum HCV RNA decreased rapidly between 8 and 24 h after the first administration (first phase) and more slowly thereafter (second phase), with median exponential decays of 2.14 and 0.11 log10/day, respectively. Four patients had sustained virological responses, nine patients had transient responses, and seven patients had no responses. The differences in the rate of first-phase viral decline among the three groups were not significant (p = 0.34), but the differences in the rate of second-phase viral decline were significant (p = 0.0004); the median viral decline (interquartile range) in the second phase was 0.48 (0.42-0.50) log10/day in patients with sustained responses, 0.16 (0.10-0.19) log10/day in patients with transient responses, and 0.026 (0.017-0.040) log10/day in patients with no responses.

CONCLUSIONS

Changes in serum levels of HCV genotype 1b in the first 2 wk of interferon-alpha treatment, monitored by real-time quantitative PCR, can be used for prediction of the long term therapeutic response.

Comparison of real-time quantitative polymerase chain reaction with three other assays for quantitation of hepatitis C virus

BACKGROUND AND AIMS

Evaluation of serum levels of hepatitis C virus (HCV) is important for predicting the response to interferon treatment and monitoring its therapeutic efficacy. The aim of this study was to evaluate real-time quantitative polymerase chain reaction (PCR) as a method for the measurement of HCV-RNA.

METHODS

The subjects were 50 patients with chronic hepatitis C: 36 with genotype 1b, eight with genotype 2a, and six with genotype 2b. Samples were tested for HCV-RNA by using real-time quantitative PCR with the ABI Prism 7700 sequence detection system, a branched DNA signal amplification assay, and an Amplicor monitor test; and for HCV core protein by using a fluorescent enzyme immunoassay.

RESULTS

The detection range of the real-time quantitative PCR was between 10(1)-10(8) copies/mL of HCV-RNA. Hepatitis C virus RNA was detectable in all 50 samples by the use of real-time quantitative PCR, but was undetectable in 14 samples by the use of a branched DNA assay and in two samples by using the Amplicor monitor test; HCV core protein was undetectable in three samples. A significant correlation was found between the results of real-time quantitative PCR and those of the three other assays: branched DNA assay (r = 0.837, P < 0.0001), Amplicor monitor test (r = 0.853, P < 0.0001), and HCV core protein concentrations (r = 0.549, P < 0.0001).

CONCLUSIONS

Our results showed that the real-time quantitative PCR was a highly sensitive assay for the measurement of HCV-RNA.

Detection of interferon-alpha expression by PCR in patients with chronic hepatitis C and hepatitis non-A, non-B

The polymerase chain reaction (PCR) was used to examine expression of interferon-alpha (IFN A) genes in general and the expression of messenger RNA (mRNA) encoding the subtypes IFN-alpha-2 and IFN-alpha-4 in blood and liver biopsy samples from patients with chronic hepatitis C or hepatitis non-A, non-B (HC/HNANB) infection entered into a trial of IFN-alpha-2a therapy. Peripheral blood mononuclear cells (PBMC) from healthy controls and HC/HNANB infected patients were studied for their capacity to produce transcripts encoding IFN-alpha after stimulation with Sendai virus. Expression at the level of mRNA for IFN A and the subtypes IFN A2 and A4 was detected in both controls and HC/HNANB infected patients PBMC and no significant difference was seen in expression of IFN A transcripts or level of total IFN-alpha secreted into culture supernatants between controls and patients. Interferon A, and specifically IFN A2 and IFN A4 transcripts were detected in a high proportion of liver biopsies from patients with HC/HNANB infection. The presence of IFN A mRNA (and specifically IFN A2 and IFN A4) showed no correlation to histological improvement nor response to therapy. The use of PCR to detect those IFN A genes that are not expressed, thereby identifying subtypes that may be lacking, could be the key to the choice of IFN-alpha subtypes that are used for effective therapy.

Short and long-term effects of interferon on serum markers of hepatitis C virus replication

Hepatitis C virus RNA (HCV-RNA) and serological markers of HCV infection were measured in 30 patients with chronic hepatitis C who had been treated with interferon (IFN). Patients were classified into four groups according to serum alanine aminotransferase (ALT) levels after treatment. These were: as complete responders (CR); partial responders (PR); transient responders (TR); and non-responders (NR). In all 11 patients in the CR group, HCV-RNA disappeared from serum for at least 24 months and anti-c100-3 decreased progressively during this time. In the PR group, four of five patients were positive for HCV-RNA in spite of the improvement of ALT levels and decline of anti-c100-3. In the TR and NR groups, HCV-RNA disappeared transiently or remained persistently positive. The results indicate that IFN-mediated improvement of ALT and decrease of anti-HCV (anti-c100-3) were not always related to the disappearance of HCV-RNA from serum. On the other hand, sustained disappearance of HCV-RNA from serum was demonstrated in the patients who did not have post-treatment ALT relapse. This indicates that IFN can eradicate HCV from serum in some patients and provide a clinical remission of chronic hepatitis C.

Vertical transmission of hepatitis C virus (HCV) detected by HCV-RNA analysis

The rate of transmission of hepatitis C virus (HCV) from patients with chronic hepatitis C to their children was studied. Of the 64 children with a parent with chronic hepatitis C, two (3%) had abnormal alanine aminotransferase (ALT) activities, six (9%) had anti-HCV detected by c100 ELISA, seven (11%) had anti-HCV detected by ELISA-II, and 21 (33%) had HCV-RNA by polymerase chain reaction (PCR). Anti-HCV detected by ELISA-II disappeared within six months in all six infants. Of the five children whose mothers were given a blood transfusion after the child's first birthday, none had anti-HCV or HCV-RNA. In the five families whose elder or eldest offspring had HCV-RNA, all of the younger offspring had HCV-RNA. The vertical transmission rate of HCV was low if judged by the presence of anti-HCV or abnormal ALT values, but the rate was high (33%) if judged by the presence of HCV-RNA.