Detection of anti-interferon-α2a antibodies in chronic liver disease

The occurrence of antibodies to interferon-alpha 2a (anti-IFN-alpha 2a) to recombinant human IFN-alpha 2a was examined in chronic liver disease by a sensitive enzyme-linked immunosorbent assay (ELISA). Naturally occurring IgG and/or IgM anti-IFN-alpha 2a were found in one of 12 cases of chronic persistent hepatitis, four of 18 cases of chronic active hepatitis (CAH), two of 12 cases of liver cirrhosis, six of seven cases of primary biliary cirrhosis, nine of 11 cases of auto-immune CAH and none of 21 normal control subjects. Fifteen patients with viral CAH were treated with recombinant IFN-alpha 2a. Two of them were positive prior to receipt of IFN-alpha 2a and their titres increased after the therapy. Two patients became positive for anti-IFN-alpha 2a after the therapy. Absorption experiments revealed that anti-IFN-alpha 2a cross-reacted with native human leucocyte IFN-alpha and recombinant IFN-alpha 2b but not with recombinant IFN-beta and -gamma. The immunoblotting experiment confirmed the binding of antibodies to IFN. The results of anti-IFN-alpha 2a obtained by antiviral, cytopathic effect assay were in good agreement with those of IgG anti-IFN-alpha 2a, but not with those of IgM antibodies obtained by the ELISA. The ELISA described in the present study is a simple, sensitive and quantitative assay for anti-IFN-alpha 2a. It should be useful in assessing sub-specificities of anti-IFN and provide valuable information to predict the effect of IFN therapy and to elucidate the immunological abnormality in liver disease.     

Interferon alpha receptors are important for antiproliferative effect of interferon-α against human hepatocellular carcinoma cells

Aim: Interferon (IFN)-alpha is a promising drug for the prevention and treatment of hepatocellular carcinoma (HCC). We reported that responders to IFN-alpha/5-fluorouracil combination therapy expressed higher IFN alpha receptor (IFNAR)2 in tumor. Herein we studied involvement of IFNARs in response to IFN-alpha in HCC cells. Methods: IFN-alpha sensitivity and expression of IFNARs were studied in six HCC cell lines (HuH7, PLC/PRF/5, HLE, HLF, HepG2, Hep3B) using growth-inhibitory and RT-PCR, Western blot assays. Short interfering RNAs (SiRNAs) against IFNAR1 and 2 were used to analyze the role of the IFNARs in IFN-alpha's effect and signal transduction. Results: The expressions of IFNAR1 and 2c mRNAs were higher in PLC/PRF/5 cells than those in other cell lines, and PLC/PRF/5 cells expressed abundant IFNAR2c on their cell membrane. When we examined the sensitivity of the HCC cell lines to the growth-inhibitory effect of IFN-alpha, PLC/PRF/5 exhibited a significant response, while the other cells were much more resistant. Knockdown of either IFNAR1 or 2 using siRNAs suppressed the IFN-alpha's signal transduction (2.5-fold), and decreased the growth-inhibitory effect (down by 69.9% and 67.3%). Conclusion: The results suggest that the expression of IFNAR1 and IFNAR2c independently are important for the antiproliferative effect of IFN-alpha in HCC cells.     

Identification of novel defective HCV clones in liver transplant recipients with recurrent HCV infection

Patients with recurrent hepatitis C after liver transplantation usually have a high viral load and are generally resistant to interferon (IFN)-alpha2b plus ribavirin (RBV) therapy. However, it remains unclear whether pretreatment viral titre determines the effectiveness of combination therapy, especially in patients with a high viral load. The aim of this study was to identify the viral factors associated with a sustained virological response (SVR) to antiviral therapy in patients with recurrent hepatitis C after living-donor liver transplantation. Twenty-three patients with recurrent hepatitis C received combination therapy of IFN-alpha2b plus RBV. SVR was achieved in 7 of the 23 patients (30.4%). Predictive factors for SVR included a 2 log10 decline in Hepatitis C virus (HCV) RNA at 2 weeks after the start of therapy and disappearance of HCV RNA at 4 or 24 weeks after the start of therapy. As the pretreatment high viral load showed no association with SVR, we asked whether other viral factor was associated with the response to the combination therapy in transplant recipients. We found the several novel defective HCV clones in 4 of 12 recipients' sera. All defective HCV clones had deletions in the envelope region. Interestingly, no patients with defective clones showed a prompt decrease in HCV RNA after the start of IFN-alpha2b plus RBV therapy. Thus, early decline in serum HCV RNA after treatment was closely associated with SVR. The circulating defective HCV clones are present and might be associated with the response to the combination therapy in patients with recurrent hepatitis after liver transplantation.     

Diabetes mellitus reduces the therapeutic effectiveness of interferon-α2b plus ribavirin therapy in patients with chronic hepatitis C

Aim: Patients with chronic hepatitis C (CHC) often have diabetes mellitus (DM). However, it is unknown whether DM affects patient response to interferon (IFN) plus ribavirin therapy. Therefore, the aim of this study was to examine the influence of DM on the outcome of IFN-alpha2b plus ribavirin therapy. Methods: In a cohort of 110 patients with CHC, the outcome of 6 months of IFN-alpha2b plus ribavirin therapy was evaluated by comparing the patients with and without DM. Results: There were 46 sustained-responders; 64 patients did not become sustained responders. Higher age (P = 0.015), lower platelet counts (P = 0.036), hepatitis C virus (HCV) serotype 1 (P = 0.001), advanced liver fibrosis (P = 0.004), and the presence of DM (P = 0.007) were significantly associated with not becoming a sustained-responder. Seventeen CHC (15%) patients had DM. Sex ratio, age, body mass index, alanine aminotransferase levels, HCV-RNA titer, and HCV serotypes did not significantly differ between the patients with and without DM, while fasting plasma glucose, hemoglobin A1c and liver histological staging were significantly different. On multiple logistic regression analysis, HCV serotype 1 (odds ratio 8.743, 95% confidence interval 2.215-34.517; P = 0.002) and the presence of DM (odds ratio 8.657, 95% confidence interval 1.462-51.276; P = 0.014) were independently associated with not becoming a sustained-responder. Conclusions: The findings indicate that DM reduces the response to IFN-alpha2b plus ribavirin therapy in CHC patients.     

Protective effect of interferon-α on the DNA- and RNA-degrading pathway in anti-Fas-antibody induced apoptosis

Aim: Fas membrane-associated polypeptide antigen is a receptor molecule responsible for apoptosis-mediated signals. In animal models of acute viral hepatitis, apoptosis of hepatocytes is mediated by Fas-death receptors; therefore, the aim of this study was to evaluate the effect of interferon (IFN)-alpha on apoptotic markers and nuclease activity against different coding and non-coding single and double stranded RNAs during Fas-induced liver apoptosis. Methods: An in vivo experiment was performed with simultaneous administration of anti-Fas (CD95) antibodies and IFN-alpha, and an in vitro experiment was performed in hepatocyte cultures treated with anti-Fas antibodies and IFN-alpha. Results: Detection of apoptosis using Annexin V-FITC/propidium iodide, Bcl-2 and Bax expression in hepatocyte cultures confirmed the appearance of early apoptotic events and progression toward late apoptosis after anti-Fas antibody treatment. IFN-alpha had a tendency to retard the apoptosis process in Fas-induced apoptosis by increasing the number of viable cells and decreasing the number of cells in late apoptosis, by increasing the percentage of Bcl-2 positive cells, by decreasing the percentage of Bax positive cells, and by decreasing the nuclease activity compared to the anti-Fas antibody treated group. Total DNA and RNA concentration was much reduced in the Fas group and DNA fragmentation assay provided evidence for increased DNA degradation. Enhanced nuclease activity against DNA, rRNA, poly(A), poly(C), poly(U), poly(I:C), and poly(A:U) was manifested in the anti-Fas antibody treated group, except for the inhibitory-bound alkaline RNase. Conclusions: The results demonstrate that the RNA-degrading pathway in Fas-induced apoptosis can accelerate the liberation of the latent enzyme from the inhibitor complex. IFN-alpha prevented enormous, Fas-ligand induced degradation of all the substrates used in this experimental study, most probably due to similarities in the signal transduction pathways. Investigations of death receptor-induced apoptosis may lead to novel treatment combinations for patients with acute or chronic liver diseases.     

Treatment of cirrhotic hepatitis C virus patients with daily doses of interferon-α2a

Summary. In patients with hepatitis C who have cirrhosis the rate of sustained response following interferon therapy is less than half that of patients without cirrhosis. It has been suggested, however, that a higher dose regime in patients with cirrhosis may improve response. The results of a recent Australian study of cirrhotic patients who were given an intense interferon programme of 4.5 MIU daily for 24 weeks were compared with previous studies of patients with hepatitis C. In the Australian study, 14% of patients had a sustained response at 6 months after end of therapy. Of 11 studies of interferon response in chronic hepatitis C comparison of pretreatment variables showed considerable differences. Identification of predictors of response by univariate and multivariate analysis regularly indicated the importance of age and fibrosis. Analysis of six studies with either a poor (5% or less) or a reasonable (14–19%) sustained response rate to interferon in patients with cirrhosis suggested that a higher dose or longer duration of therapy was associated with better results. The experience of the Australian study, where 14% of patients had a sustained biochemical response to interferon and side-effects were reasonably tolerated with careful monitoring, suggests that future studies in cirrhosis should be carried out exploring higher doses and longer durations of therapy.     

Combination low-dose lymphoblastoid interferon and thymosin α1 therapy in the treatment of chronic hepatitis B

SUMMARY. This open label study was initiated to assess the safety and efficacy of lymphoblastoid interferon-α (IFN-α) and thymosin α₁ (Tα₁) in the treatment of 11 patients with chronic hepatitis B, who had failed to respond to standard IFN-α2b therapy, and in four interferon naive patients. These fifteen hepatitis B surface antigen (HBsAg) positive and serum hepatitis B virus (HBV) DNA positive patients were given Tα₁ (1 mg) subcutaneously (sc) on 4 consecutive days. Low-dose lymphoblastoid IFN-α (3 MU) was administered intramuscularly (IM) on the fourth day. Beginning with the second and for the subsequent 25 weeks, patients self-administered Tα₁ twice weekly in the morning followed, 12 h later, by 3 million units (MU) lymphoblastoid IFN-α. Patients were followed-up for 12 months. Nine (60%) of the 15 patients, including six (55%) of the 11 patients previously treated with IFN-α2b, responded by losing serum HBV DNA and normalizing alanine aminotransferase (ALT) values. Six of the nine responders seroconverted to HBsAg negativity. Significant improvements in the Knodell histological activity index were observed in the responders and no significant adverse effects were observed. Combination low-dose lymphoblastoid IFN-α and Tα₁ treatment may provide a safe and potentially effective therapeutic approach in chronic hepatitis B. These results require confirmation in future randomized controlled studies.     

Neutralizing anti-interferon-α antibodies and response to treatment in patients with Ph+ chronic myeloid leukaemia sequentially treated with recombinant (α2a) and lymphoblastoid interferon-α

Neutralizing anti-IFNα antibodies (nIFNα Abs) occur in a significant proportion of patients with hairy cell leukaemia, hepatitis or solid tumours treated with recombinant IFNα (IFNα2a or IFNα2b), but information on their incidence in chronic myeloid leukaemia (CML) is scanty and their clinical relevance is not yet completely defined. By using an IFNα antiviral neutralization bioassay, the frequency of nIFNα2a Abs was evaluated in 67 Ph⁺ CML patients during IFNα2a therapy at doses ranging from 6 to 9 MU/d. 15 patients (22%) developed nIFNα2a Abs (titre ranging from 1:40 to 1:20480) and 11/15 (73%) were haematologically and/or karyotypically unresponsive to treatment. 52 patients did not develop antibodies and 11 of them (21%) were unresponsive. The negative relationship between the positivity for nIFNα2a Abs and the response to treatment was highly significant ( P  = 0.0001). In nine nIFNα2a Abs positive patients, treatment was changed from recombinant IFNα2a to lymphoblastoid IFNα (IFNα-ly), at the same dose and schedule. After 9 months of IFNα-ly treatment a haematological response was achieved in 4/7 cases who were non-responsive to prior IFNα2a therapy and was maintained in the other two patients previously responsive to IFNα2a. However, no karyotypic response was observed. This data shows that a significant proportion of Ph⁺ CML patients receiving treatment with IFNα2a can develop neutralizing antibodies and that these antibodies are associated with a loss of IFNα2a efficacy. Changing the patients to treatment with lymphoblastoid IFNα may restore haematological response but it is not likely to induce a karyotypic response.     

Growth inhibitory effects of pegylated IFN alpha-2b on human liver cancer cells in vitro and in vivo.

PURPOSE: We investigated the effects of pegylated IFN-alpha2b (PEG-IFN-alpha2b) on the growth of human liver cancer cells. METHODS: The effect of PEG-IFN-alpha2b on the proliferation of 13 liver cancer cell lines was investigated in vitro. Chronological changes in growth and IFN-alpha receptor-2 (IFNAR-2) expression were monitored in hepatocellular carcinoma (HCC) cells (HAK-1B) cultured with PEG-IFN-alpha2b. After HAK-1B cells were transplanted into nude mice, various doses of PEG-IFN-alpha2b or IFN-alpha2b were administered, and tumor volume, weight, histology, and IFNAR-2 expression were examined. RESULTS: PEG-IFN-alpha2b inhibited the growth of nine cell lines with apoptosis in a dose- and time-dependent manner. Continuous contact with PEG-IFN-alpha2b induced time-dependent growth inhibition and down-regulation of IFNAR-2 expression. PEG-IFN-alpha2b induced a dose-dependent decrease in tumor volume and weight, a significant increase of apoptotic cells, and a decrease in IFNAR-2 expression in the tumor. The clinical dose for chronic hepatitis C was also effective. The antitumor effect of PEG-IFN-alpha2b was significantly stronger than that of non-PEG-IFN-alpha2b in vivo. CONCLUSIONS: Continuous contact with PEG-IFN-alpha2b induces strong antitumor effects and the down-regulation of IFNAR-2 in HCC cells. The data suggest potential clinical application of PEG-IFN-alpha2b for the prevention and treatment of HCC.     

A common Vδ2—Dδ2—Dδ3 T cell receptor gene rearrangement in precursor B acute lymphoblastic leukaemia

Despite their apparent commitment to the B lymphocytic lineage, human precursor B cell acute lymphoblastic leukaemias (ALL) frequently rearrange their T cell antigen receptor (TCR) alpha, beta and gamma chain genes. Since these three genes are active sites of rearrangement in precursor B cell neoplasms, it seemed that the recently discovered fourth TCR gene, delta, might be similarly rearranged. To investigate this possibility, a series of precursor B cell leukaemias was analysed for rearrangements at the delta chain gene locus, using probes of the variable, joining, and constant regions of the delta chain gene. The majority of precursor B cell ALLs in this series (25/32, 78%) showed rearrangement or deletion of one or more TCR delta genes. This contrasts sharply with a series of 16 mature B cell neoplasms (chronic lymphocytic leukaemia) in which no TCR delta gene rearrangements were detected. An unusual TCR delta rearrangement, rarely observed in normal or neoplastic T cells, was seen in the majority (14/18) of precursor B cell ALLs with TCR delta rearrangements. In contrast to the utilization ov V delta 1 in T cell ALL, detailed restriction mapping of precursor B ALL revealed an incomplete rearrangement without involvement of J delta segments. Direct genomic sequencing was performed on one example and demonstrated a nonproductive V delta 2-D delta 2-D delta 3 recombination in this precursor B ALL. We conclude that the TCR delta chain gene is an active locus in precursor B cell neoplasia, involves an unusual type of rearrangement and provides a clonal tumour marker for diagnosis of precursor B ALL.     

High-dose natural interferon-α therapy for chronic hepatitis C with a high viral load: Predictors of efficacy

BACKGROUND: The effectiveness of interferon against hepatitis C has been found to be greatly affected by viral factors. However, few controlled interferon trials have involved seemingly intractable cases of chronic hepatitis C. METHODS: In 44 patients with high hepatitis C virus RNA levels (> or = 10(5) copies/mL), we carried out a prospective, controlled study of two natural interferon-alpha regimens, seeking predictors of therapeutic efficacy. Total natural interferon-alpha doses over 6 months in two groups were 780 and 840 million units, respectively. RESULTS: High therapeutic efficacy was achieved with no significant outcome difference between the regimens. The virus eradication rate was 35% and the rate of sustained biochemical response was 45% for both regimens. Multivariate logistic regression analysis identified viral genotype as the only significant predictor of success in viral eradication. CONCLUSIONS: Hepatitis C virus genotype 2 showed high sensitivity to interferon-alpha and this therapy can be recommended even for patients with a high viral load of this genotype. In contrast, with genotype 1b, cure was extremely difficult in cases with 10(7) or more copies/mL with a single 6-month course of interferon-alpha.     

Efficacy of interferon-alpha treatment in Japanese children with chronic hepatitis C

BACKGROUND: We investigated the efficacy of natural interferon (IFN)-alpha treatment in 34 Japanese children with chronic hepatitis C. METHODS: Thirty-four children completed 6 months of therapy with natural IFN-alpha and were followed for 12 months or longer. We examined the serum hepatitis C virus (HCV) RNA titer and liver histology before, during, and after IFN treatment. RESULTS: At 6 months after the cessation of IFN-alpha treatment, 16 patients (47%) had normal serum alanine aminotransferase concentration and no detectable serum HCV RNA. There were no major side-effects, excluding some influenza-like symptoms during the IFN-alpha treatment. Most genotype 2a patients had a complete response (80%). Moreover, patients who had a low HCV RNA titer (<102 copies/mL) after 1 month of IFN-alpha treatment became complete responders at 6 months after the cessation of treatment. Histological improvement was observed in almost all patients after IFN-alpha treatment. CONCLUSION: Interferon-alpha treatment is safe and effective for children with chronic hepatitis C and has no serious side-effects. A HCV RNA concentration of <102 copies/mL after 1 month of IFN-alpha treatment and genotype 2a may be useful predictors of long-term IFN efficacy.     

Pegylated interferon-alpha 2b-ribavirin combination in Egyptian patients with genotype 4 chronic hepatitis

Egypt has a high prevalence rate of hepatitis C (HCV) infection and as much as 90% is genotype 4. Response to interferon (IFN) varies with viral genotype and degree of fibrosis. Genotype 4 is poorly sensitive to standard IFN and IFN-ribavirin combination. We evaluated pegylated interferon (PEG-IFN)-alpha2b in our patients. Sixty-one patients with compensated chronic HCV genotype 4 were enrolled in two groups: group A (31 patients) received IFN-alpha2b 3 MU three times per week and group B (30 patients) received 1.5 mug/kg PEG-IFN-alpha2b once weekly. Ribavirin was added to each regimen in a dose of 800-1200 mg based on body weight. Patients were followed up for 24 weeks to assess the sustained response (SR). End-of-treatment response (ETR) was achieved in 11 of 31 patients (35.48%) in group A, and 13 of 30 patients (43.33%) in group B (P < 0.05). Only eight patients in group A and 10 in group (B) achieved a sustained virological response (25.8 and 33.3%, respectively) (P < 0.05). By computing ETR, SR or relapse and pretreatment baseline data (pretreatment, viral load, alanine transaminases, necroinflammatory and hepatic fibrosis), both inter- and intragroup, no significant correlations could be detected. In terms of safety and tolerability, PEG-IFN-alpha2b and IFN-alpha2b were comparable. In spite of mild insignificant increase in ETR and SR with the pegylated form, the poor response of genotype 4 in Egypt (genotype 4a) to different forms of IFNs may be related to an intrinsic resistance to the direct antiviral effect of IFN.     

Recombinant interferon-α therapy for acute hepatitis B: a randomized, double-blind, placebo-controlled trial

In spite of the availability of hepatitis B vaccine, acute hepatitis B continues to be a worldwide problem for which no specific therapy is available. We investigated the safety and the effectiveness of recombinant interferon-α2b (rIFN-α2b) in the treatment of acute hepatitis B by determining overall severity and duration of symptoms, time required to clear viral antigens and hepatitis B virus (HBV) DNA, and titre of antibodies to hepatitis B surface antigen (HBsAb), 24 weeks after the onset of therapy. One hundred patients were randomly assigned to treatment with either 3 million units (MU) ( n =34) or 10MU ( n =33) rIFN-α2b or to placebo ( n =33), three times weekly for 3 weeks. Follow-up was for 24 weeks. A significantly shorter duration of the symptoms and signs of acute hepatitis was observed in patients who received 3MU rIFN-α2b compared with those who received 10MU rIFN-α2b or placebo. Twenty-one weeks post-therapy, patients treated with 10MU rIFN-α2b showed a significantly higher geometric mean HBsAb titre than those treated with placebo (85.1 vs 35.5IUl^–1, P <0.05). rIFN-α2b administration was well tolerated even in jaundiced patients. No serious side-effects were observed necessitating reduction in dose or discontinuation of the drug. The effect of rIFN-α2b on transition of HBV infection to chronicity could not be evaluated in this trial because such an unfavourable course was not seen in any of the treated or the control patients. In conclusion, rIFN-α2b was safe in acute hepatitis B, and at low dose was found to ameliorate symptoms and to shorten significantly the duration of illness.     

Long-term retreatment in chronic hepatitis C patients who were non-responders to an initial course of interferon-α2b

Nineteen patients with chronic hepatitis C who were virological non-responders (seven responder/relapse and 12 no response) to an initial 24-week course of interferon-α2b (IFN-α2b) at a dose of 3million units (MU) thrice weekly were retreated for an additional 48 weeks at the same dosing schedule and followed-up for another 24 weeks post-therapy. At the end of follow-up (week 72), six (32%) of the 19 patients were hepatitis C virus (HCV) RNA negative and were virological complete responders to retreatment. The viral genotypes in these six patients included two each with 1b and 3a, one with 2b, and another with 2a/2b; five of the six virological responder patients had cirrhosis. Significant predictors for successful retreatment included lower baseline HCV RNA concentrations prior to the first course of therapy, 2 log₁₀ reductions in serum HCV RNA during the initial treatment and classification into the virological ‘responder/relapse’ category after the first course of IFN (P < 0.01 for all observations). When the above factors were used to construct a predictive model to determine response to retreatment, it was found that the absence of a 2 log₁₀ drop in HCV RNA concentrations during the first course of IFN therapy was the most reliable indicator of non-response to retreatment (likelihood ratio = 10, P = 0.0014). In addition, the presence of HCV RNA at week 12 of retreatment was 100% predictive of virological non-response to the 48-week course of therapy. Our findings indicate that an additional 48-week course of IFN-α2b therapy at 3 MU thrice weekly will achieve a virological complete response in 60% of patients who had a 2 log₁₀ drop in HCV RNA during their first course of treatment, and measurement of week-12 HCV RNA during retreatment to identify non-responders is beneficial to patients as well as being cost-effective. Thus, a second course of IFN remains a viable option in a subgroup of non-responder patients, regardless of genotype or the presence of compensated cirrhosis.     

Significance of β2-Microglobulin in Liver Diseases

Serum levels of beta 2-microglobulin (beta 2-M) were found to be significantly elevated in acute viral hepatitis, chronic persistent or active hepatitis and liver cirrhosis. beta 2-M values were significantly lower in chronic persistent hepatitis than in the three other groups. Serum beta 2-M was normal in 75 asymptomatic carriers of HBsAg. Steroid therapy was followed by reduction of serum beta 2-M levels in 11 cases of chronic active hepatitis. Variations of beta 2-M were independent from that of transaminases, bilirubin and gamma-globulins.     

Hepatitis C virus RNA and long-term response to recombinant interferon-α2b in patients with chronic hepatitis C

Summary. The effectiveness of recombinant interferon-α2b (rIFN-α2b) in eradicating hepatitis C virus (HCV) RNA from serum has not been completely assessed. We studied 39 patients with compensated chronic hepatitis C diagnosed by liver biopsy and positive HCV RNA measured by polymerase chain reaction (PCR). Group I consisted of 26 patients treated with 3 MU of rIFN-α2b for 6 months; group II, 13 control patients observed for six months; and group III, 12 out of 13 patients from group n who subsequently received 5 MU of rIFN-α2b for 6 months. In group I, 11 out of 23 (47.8%) patients who completed treatment had an immediate response and five (21.7%) had a sustained response to therapy six months after treatment. No response was observed in patients from group II. In group III, 7 out of 12 (58.3%) patients who completed treatment had an immediate response and none had a sustained response. Considering all patients who completed rIFN-α2b treatment, HCV RNA remained positive at the end of therapy in three of five sustained responders (60%), six of 13 patients who relapsed (46.1%), and in all non-responders (100%). HCV RNA was positive 6 months after therapy in four (80%), 13 (100%). and 17 (100%) patients respectively. All patients with a sustained response had normal aminotransferase levels 18 months after therapy. We conclude that in chronic hepatitis C rIFN-α2b causes a significant immediate response but this is not sustained, only 2.8% of treated patients had a sustained loss of HCV RNA. Normal aminotransferase persist in the long term, despite persistence of HCV RNA.     

Transduction of human hepatocellular carcinoma cells with human alpha-interferon gene via retroviral vector

AIM:To investigate the therapeutic potential of gamma interferon (IFN-alpha) genemodified human hepatocellular carcinoma (HCC) cells.METHODS:The IFN-alpha gene was introduced retrovirally into four HCC cell lines.Secreted IFN-alpha activity was assessed using bioassay. The expression of MHC molecules was detected by FACS.Tumorigenicity was analysed by tumor formation in nude mice.RESULTS:Four IFN-alpha gene transduced HCC cell lines secreted different amounts of IFN-alpha, as in the same case of five clones derived from one HCC cell line. Transduction with IFN-alpha caused significant increase in the expression of major histocompatibility complex (MHC) antigens on HCC cells. The expression of HLA class I was increased by 2-3 times in terms of mean fluorescence intensities, while for class II expression, the percentage of positive cells augmented from < 10% to &lg 50%. When equal amount of tumor cells were injected into nude mice, the tumor igenicity some transduced cells decreased dramantically.CONCLUSION:IFN-alpha gene transduction can convert weakly imunogenic HCC cells to activate antitumor immune response, and further pave the way for the future use of such gene modified tumor cells as a modality for the cancer immunotherapy.