In vivo interferon system assessed by 2'-5' oligoadenylate synthetase activity in chronic hepatitis C virus patients treated with pegylated interferon and ribavirin.

AIM: 2',5' oligoadenylate synthetase (2-5AS), an enzyme induced by interferon, is an accurate indicator of the antiviral effect of interferon. We measured it during pegylated interferon based therapies in patients with chronic hepatitis C virus (HCV) in order to determine the dynamics of antiviral status in vivo and the relationship between the response to exogenous interferon and the outcome of therapy. METHODS: A total of 160 patients with chronic HCV were treated with pegylated interferon alfa 2a or 2b or non-pegylated interferon, with or without ribavirin. Serum 2-5AS activity was measured by radioimmunoassay assay kits every 2 weeks. RESULTS: In 60 patients treated with pegylated interferon alfa 2a or 2b, 2-5AS levels increased to 7-40 times (average 235 pmol/dL) above the pretreatment levels (30 pmol/dL), which were significantly higher than the levels during non-pegylated interferon therapy. Ribavirin did not enhance 2-5AS levels. 2-5AS levels between sustained virological response (SVR) and non-SVR, including null responders to pegylated interferon plus ribavirin therapy were not significantly different. CONCLUSION: 2-5AS levels were significantly higher in patients treated with pegylated interferon than in those treated with non-pegylated interferon, suggesting that pegylated interferon is more potent at inducing interferon response genes resulting in an improved antiviral effect. Ribavirin did not appear to be related to interferon response gene induction.

Early reduction of infected hepatocytes by activated immunity at the time of interferon withdrawal hepatitis followed by lamivudine administration resulted in higher seroconversion in hepatitis Be antigen-positive patients with chronic hepatitis B.

BACKGROUND: It has been found that the efficacy of lamivudine (LAM) therapy can be improved by preceding administration with a short course of corticosteroid that induces a flare of the disease upon its withdrawal. Because of the side effects of corticosteroid, we tested the effect of a short course of interferon (IFN) as the primer instead of prednisolone, which was followed by LAM when the hepatitis flare occurred. The incidence of LAM resistance mutations and the effect of core promoter and precore mutations on the durability of the responses were also studied. METHODS: Patients treated with interferon (IFN)-LAM therapy (n=73) were compared to those treated with IFN alone (n=117). The IFN-LAM group received IFN-alpha MU/day, t.i.w. for a 3-month period. LAM (10mg/day during 1 year) was started when IFN withdrawal hepatitis occurred during 2-10 months after stopping IFN. The LAM-resistant, core promoter, and precore mutations were examined by sequencing. RESULTS: (1) The IFN-LAM group developed exacerbated hepatitis following IFN withdrawal in 63 patients before starting LAM therapy. The seroconversion (SC) rate was significantly higher in the IFN-LAM group than in the IFN-alone group (61% vs 26%, P=0.0001). (2) The LAM resistance mutation rate was 31% at 1 year after initiating LAM therapy. (3) In a stepwise discriminant-function analysis, decreased level of HBeAg determined at 4 weeks after LAM administration and increased level of HBeAb before the start of LAM administration contributed significantly on seroconversion to anti-HBe (P = 0.0073 and 0.004, respectively). (4) The reappearance rate of HBeAg within 6 months after the therapy (relapse) was 33% in the IFN-LAM group and 10% in the IFN-alone group. The prevalence of core promoter and precore mutations did not change before and after the therapy, nor did these mutations correlate with the relapse after stopping IFN-LAM therapy. CONCLUSIONS: (1) Our findings suggest that early reduction of infected hepatocytes expressed by HBeAg by LAM may contribute to a high SC rate of IFN-LAM therapy. (2) The emergence of LAM-resistant mutations was similar to the previously reported rate, and neither core promoter nor precore mutations correlated with relapse of seroconverters after IFN-LAM withdrawal.

The predictive value of liver fibrosis in determining the effectiveness of interferon and lamivudine therapies for chronic hepatitis B.

BACKGROUND: To determine the best indicator of the effective use of interferon and lamivudine for the treatment of hepatitis B e antigen-positive chronic hepatitis, we retrospectively analyzed histologic and virologic status in 200 patients who were treated with interferon and 45 patients who were treated with lamivudine. METHODS: Histological grading and staging scores were determined by international criteria and the METAVIR scoring system. The YMDD motif associated with lamivudine resistance was analyzed by the sequencing of hepatitis B virus (HBV) DNA. RESULTS: Of 200 interferon-treated patients, 62 (31%) seroconverted to anti-hepatitis B e (anti-HBe). Multivariate analysis showed that the significantly important predictors of response were a higher grading score (P = 0.0056) and lower staging score (P = 0.0010). Twenty (44%) of the 45 lamivudine-treated patients seroconverted to anti-HBe, and multivariate analysis showed that the significantly important predictors of response were a higher alanine aminotransferase (ALT) level (P = 0.0034) and lower hepatitis B e antigen levels ( P = 0.0128). YMDD mutations occurred during therapy in 12 patients (27%). The significantly important predictor of the development of mutation was a higher staging score (P = 0.0226). CONCLUSIONS: Both interferon and lamivudine were effective for patients with high ALT levels, but interferon's efficacy appeared to be limited by the degree of fibrosis. Lamivudine appeared to be effective irrespective of the degree of fibrosis, but YMDD mutations seemed to develop sooner in patients with advanced liver fibrosis.

Genetic changes in hypervariable region 1 as a possible mechanism for biochemical responders with interferon therapy.

AIM: Approximately 10% of chronic hepatitis C patients who were treated with interferon have a sustained normalization of aminotransferase levels after interferon therapy without HCV RNA clearance. We investigated genetic change in hypervariable region 1 (HVR 1) to see if the mutation in this region is responsible for their sustained biochemical response and relapse thereafter. A total of 250 patients with chronic hepatitis C who were treated with interferon were studied for 8 to 11 years post therapy. Of these, 26 were biochemical responders (BR) whose ALT remained normal without viral clearance for more than 6 months after IFN therapy. HVR 1 was examined by direct sequencing of the PCR products, and found that no significant HVR 1 differences were observed in samples obtained pretreatment, posttreatment or during flares from these patients, suggesting that mutations in this region were not responsible for either the persistence of the HCV RNA or for the ALT relapses thereafter.