Therapy of chronic hepatitis B with recombinant human alpha and gamma interferon

IFN-γ: A Crucial Player in the Fight Against HBV Infection?

About 0.8 million people die because of hepatitis B virus (HBV) infection each year. In around 5% of infected adults, the immune system is ineffective in countering HBV infection, leading to chronic hepatitis B (CHB). CHB is associated with hepatocellular carcinoma, which can lead to patient death. Unfortunately, although current treatments against CHB allow control of HBV infection, they are unable to achieve complete eradication of the virus. Cytokines of the IFN family represent part of the innate immune system and are key players in virus elimination. IFN secretion induces the expression of interferon stimulated genes, producing proteins that have antiviral properties and that are essential to cell-autonomous immunity. IFN-α is commonly used as a therapeutic approach for CHB. In addition, IFN-γ has been identified as the main IFN family member responsible for HBV eradication during acute infection. In this review, we summarize the key evidence gained from cellular or animal models of HBV replication or infection concerning the potential anti-HBV roles of IFN-γ with a particular focus on some IFN-γ-inducible genes.

Antifibrotics for chronic hepatitis C

Development and testing of antifibrotic agents for the treatment of chronic hepatitis C have generally been targeted toward hepatic stellate cells, transforming growth factor-beta, the inflammatory response, or extracellular matrix accumulation. Although several agents such as interferon-gamma, long-term pegylated interferon, and caspase inhibitors have been studied, none have proved to be effective to date. There is a clear need for drugs that inhibit or reverse hepatic fibrosis as these would be immediately applicable to patients for whom antiviral therapy has failed or who have contraindications to antiviral therapy such as those with decompensated liver disease or renal failure. A major impediment in the development of new drugs in this field has been the inability to identify appropriate histologic or clinical end points within a reasonable period of study. Progress on providing suitable end points to therapy will then promote the development of newer agents.

Inhibition of hepatitis B virus DNA replicative intermediate forms by recombinant interferon-γ

AIM: To evaluate the in vitro anti-HBV activity of recombinant human IFN-γ, alone and in combination with lamivudine.

METHODS: A recombinant baculovirus-HBV/HepG2 culture system was developed which could support productive HBV infection in vitro. Expression of HBsAg and HBeAg in infected HepG2 culture medium was detected by commercial enzyme immunoassays. HBV DNA replication intermediates were detected in infected cells by Southern hybridization and viral DNA load was determined by dot hybridization.

RESULTS: IFN-γ at 0.1 to 5 μg/L efficiently down regulated HBsAg expression in transduced HepG2 cells. At 5 μg/L, IFN-γ also suppressed HBV DNA replication in these cells. While treatment with a combination of lamivudine and IFN-γ showed no additive effect, sequential treatment first with lamivudine and then IFN-γ was found to be promising. In this culture system the best HBV suppression was observed with a pulse of 2 μmol/L lamivudine for two days, followed by 1 μg/L IFN-γ for another four days. Compared to treatment with lamivudine alone, the sequential use of 0.2 μmol/L lamivudine for two days, followed by 5 μg/L IFN-γ for six days showed a 72% reduction in HBV cccDNA pool.

CONCLUSION: This in vitro study warrants further evaluation of a combination of IFN-γ and lamivudine, especially in IFN-α non-responder chronic hepatitis B patients. A reduced duration of lamivudine treatment would also restrict the emergence of drug-resistant HBV mutants.

Successful treatment with novel triple drug combination consisting of interferon-gamma, interferon alfacon-1, and ribavirin in a nonresponder HCV patient to pegylated interferon therapy

Despite major advances in therapy of hepatitis C over the past decade, nearly half of the patients treated with the currently available regimens do not clear the virus. Therefore, there is a large unmet need for more effective therapy for patients who have failed pegylated interferon plus ribavirin therapy. We describe a case of a HCV genotype 1b patient who had failed previous combination therapies of interferon plus ribavirin and pegylated interferon plus ribavirin and was subsequently successfully treated with a novel triple drug combination consisting of interferon-gamma plus interferon alfacon plus ribavirin with the outcome of a sustained virologic response. This triple drug therapy combination could be an option for patients who have failed therapies with currently available pegylated interferons plus ribavirin. Prospective randomized studies are required to evaluate the effectiveness and tolerability of this regimen in this patient population.

Pilot study of interferon gamma for chronic hepatitis C

BACKGROUND/AIMS

Currently, there are no effective therapies available for patients with chronic hepatitis C who have failed to respond to optimal interferon alfa-based regimens. The aims of this pilot study were to assess the antiviral activity and safety of interferon gamma in chronic hepatitis C.

METHODS

Patients with chronic hepatitis C, genotype 1, who had not responded to or who had relapsed after therapy with interferon alfa and ribavirin were enrolled in a trial of interferon gamma 1b given in doses of 100, 200 or 400 microg subcutaneously three times weekly for 4 weeks. Frequent blood samples were obtained for HCV RNA levels.

RESULTS

Fourteen patients were enrolled. Geometric mean HCV RNA levels remained unchanged. Serum aminotransferase levels also did not change, while there were significant decreases in neutrophil counts (-41% from baseline) and hematocrit (-5%). Low grade fever and malaise were common with the first injection of interferon gamma, but no serious side effects were encountered.

CONCLUSIONS

Although relatively well tolerated, interferon gamma in doses of 100-400 microg thrice weekly had no effect on HCV RNA levels in patients with chronic hepatitis C who had failed to achieve a sustained response to interferon alfa-based therapies.

Nonresponders to hepatitis C virus antiviral therapy: pegylated interferons and beyond

Nonresponders to prior antiviral therapy are a heterogeneous but growing population of hepatitis C patients in the United States. The likelihood of response to retreatment with pegylated interferon(PEG IFN) and ribavirin (RBV) is largely dependent upon hepatitis C virus genotype and the type, duration, and response to prior antiviral therapy. Investigational trials with clinical and histological end points for nonresponders with advanced fibrosis including maintenance PEG IFN and other antifibrotic agents should be completed in the next 5 years. In the interim, decisions regarding retreatment with PEG IFN and RBV should be made on a case-by-case basis after considering the tolerability of prior treatment, the severity of underlying liver disease, and the anticipated likelihood of response.

Developments in the treatment of chronic hepatitis C

Hepatitis C virus is the most common chronic, blood-bourne infection, affecting 170 million people worldwide, approximately 3% of the global population. Of those infected with hepatitis C virus, 50 - 85% will develop chronic hepatitis C. Although hepatitis C is primarily a disease of the liver, a diagnosis is currently defined by the presence of the hepatitis C virus and treatment success is defined by the clearance of the virus. IFN-alpha is currently the mainstay of chronic hepatitis C therapy; the antiviral and anti-inflammatory components of IFN target both the infectious and the hepatic manifestations of the disease. However, even in combination with ribavirin, interferon therapy is not fully efficacious. Recently, the search for a more effective treatment has led investigators to optimise interferon therapy by developing pegylated interferons. Challenges facing our current treatment of hepatitis C virus include lack of efficacy in patients with difficult-to-treat disease, such as patients with cirrhosis or infected with hepatitis C virus genotype 1 (who represent a majority of US hepatitis C virus infections), the toxicity of combination therapy, the expense and difficulty of therapy and the poor reception of these treatments by many patients. The development of new hepatitis C antiviral agents is critical to our management of this disease. A number of approaches are under investigation, including long-acting interferons, immunomodulators, antifibrotics, specific hepatitis C virus-derived enzyme inhibitors, drugs that either block hepatitis C virus antigen production from RNA or prevent normal processing of hepatitis C virus proteins and other molecular approaches to treating hepatitis C virus, such as ribozymes and antisense oligonucleotides.

New therapies for chronic hepatitis B

Currently, the only therapy of proven benefit in chronic hepatitis B is interferon-alpha which leads to a long-term benefit in only one-third of patients. New therapies for hepatitis B fall into three categories; antiviral chemotherapy, immunomodulation with cell-based therapies, vaccines or cytokines, and gene therapy such as with antisense oligonucleotides, ribozymes or viral mutants. The most promising immediate approach to therapy is with the new nucleoside antivirals--lamivudine and famciclovir. These drugs are well absorbed orally, result in profound inhibition of circulating hepatitis B virus, and, in some cases, loss of hepatitis B e antigen and improvement in serum aminotransferases. Controlled trials of long-term famciclovir and lamivudine therapy currently underway aim to show whether these drugs are safe and can provide sustained inhibition of viral replication and attentant improvement in liver disease.

Interferon-alpha 2b improves short-term survival in patients transplanted for chronic liver failure caused by hepatitis B

Liver transplantation for cirrhosis caused by hepatitis B virus (HBV) has a poor prognosis. This is primarily a consequence of the near universal reinfection of the allograft, subsequent accelerated hepatic disease while receiving immunosuppression, and a reduced long-term survival. Because interferon-alpha has been shown to have an antiviral effect on HBV, a study was initiated in 1986 to assess the effect of interferon-alpha therapy on the course of liver transplantation in HBV-positive recipients. Twenty-eight patients with decompensated endstage liver disease caused by HBV were treated with 5, 2.5 or 1.25 million units (MU) of human recombinant interferon-alpha 2b (r-IFN-alpha 2b) daily for a minimum of 14 days prior to transplantation and continuing for 42 days post-transplantation. HBV antigens, HBV antibodies, HBV DNA and serum transaminase levels were measured throughout the treatment and post-treatment period. HBV DNA was eliminated in 10 of 19 patients, who survived 3 months or more post-transplantation, and was associated with a significant flare of hepatitis as detected by symptoms and transaminase levels (P < 0.05). Patients who cleared HBV DNA had lower HBV DNA levels (P < 0.05) at entry compared with those who did not. While four of 10 patients with hepatitis B e antigen (HBeAg) converted to hepatitis B e antibody (HBeAb), no surviving patient cleared hepatitis B surface antigen (HBsAg) on a long-term basis. Nonetheless, post-transplant survival was significantly better (P < 0.0001, median follow-up 42 months) in the IFN-alpha treated patients as compared with historical controls, and was similar to that of patients transplanted for all causes of parenchymal liver disease other than HBV cancer. Hence IFN-alpha therapy in the perioperative liver transplantation period improves short-term survival but does not prevent HBV infection of the allograft.

Upregulation of MHC class II antigen on dendritic cells from hepatitis B virus transgenic mice by interferon-gamma: abrogation of immune response defect to a T-cell-dependent antigen

The experiments presented here were performed to see whether the level of expression of major histocompatibility complex (MHC) class II antigen (Ia antigen) on dendritic cells, one of the most critical antigen presenting cells (APC), influences the humoral immune response in hepatitis B virus (HBV) transgenic mice. We have reported that transgenic mice had a low responsiveness in specific antibody production to keyhole limpet haemocyanin (KLH), a T-cell dependent, HBV-unrelated antigen compared with the age, sex, and major histocompatibility-matched normal mice, due to a significantly lower T-cell stimulatory capacity of transgenic mice-derived dendritic cells, possibly as a result of significantly lower level of Ia antigen. Immunohistochemical staining has shown that treatment of transgenic mice with mouse recombinant interferon-gamma (IFN-gamma), daily for six consecutive days resulted in an increased expression of Ia antigen on splenic dendritic cells. Again, flow cytometric analyses have further confirmed the significant increase in the expression of Ia antigen on dendritic cells, isolated from transgenic mice treated with IFN-gamma compared with the same from the untreated or phosphate-buffered saline (PBS)-treated transgenic mice. Transgenic mice immunized with two optimum doses of KLH (5 micrograms/mouse) could not produce anti-KLH antibodies in sera, but injecting transgenic mice with the same doses of KLH together with IFN-gamma resulted in the production of anti-KLH antibodies in sera. Again, KLH-primed normal mice-derived T/B lymphocytes produced anti-KLH antibody, when cultured with dendritic cells from IFN-gamma-treated transgenic mice expressing a higher level of Ia antigen, but not with the same from PBS-treated or untreated transgenic mice. Treatment of transgenic mice with IFN-gamma resulted in a reduced level of hepatitis B virus (HBV) DNA in liver and in sera. These experiments have shown that the level of expression of Ia antigen on dendritic cells is a critical factor for its APC capability and its modulation of IFN-gamma may be used for immune therapy in HBV carriers.

Therapy for chronic hepatitis B infection

Interferon-alpha is currently the only therapy approved for treatment of chronic HBV in the United States and Europe. Interferon-alpha therapy causes loss of HBeAg and HBV DNA in approximately a third of treated patients, and the loss of these markers of active viral replication is associated with improvements in hepatic histology and ALT levels. However, the long-term effects of interferon-alpha on morbidity and mortality, and especially on the incidence of the complications of chronic HBV infection, remain to be defined. The currently available treatment for chronic HBV is far from perfect. Interferon therapy is usually associated with significant side effects and requires subcutaneous administration. Additionally, there are a large number of patients who either fail to meet criteria for treatment, or who, with therapy, fail to respond (at least 60% of all patients). Moreover, interferon treatment is expensive (approximately $5,000 for a 16 week course of 5MU daily). Hence the search continues for effective, orally-available and cost-efficacious therapy. Of the agents available, the nucleoside analogues appear to have the greatest promise. The availability of cell culture systems and animal models for studying potential anti-HBV drugs will aid in the future development of these agents. Therapeutic vaccines, and combination therapies (given either concurrently or sequentially) may also play a future role in the management of chronic HBV infection. While prevention of disease must be a primary goal in the war against this common infection, a continued focus must be maintained on the treatment of the approximately 300 million individuals world-wide with established chronic HBV infection.

Tumor necrosis factor-alpha and interferon-gamma inhibit synergistically viral replication in hepatitis B virus-replicating cells

The effects of tumor necrosis factor-alpha and/or interferon-gamma on the replication of hepatitis B virus were examined using HB611 cells. These cells were derived from human hepatoblastoma cells, Huh6, by integrating hepatitis B virus DNA, and produce hepatitis B virus continuously. Each of the cytokines inhibited hepatitis B virus replication in the cells assessed as the amount of episomal hepatitis B virus DNA, without a decrease in cell viability. When the two cytokines were administered together, the inhibitory effect became greater. Incubation of the cells with 1,000 U/ml tumor necrosis factor-alpha decreased HBV DNA replicative intermediates by 55%, and that with 1,000 U/ml interferon-gamma decreased these by 51%. Furthermore, incubation with 1,000 U/ml tumor necrosis factor-alpha and 1,000 U/ml interferon-gamma in combination decreased HBV DNA replicative intermediates by 71%. In contrast, the amount of hepatitis B virus RNA and secretion of hepatitis B e antigen were not apparently reduced by the cytokines, and 2',5'-oligoadenylate synthetase activity was not detected in the supernatant. These results suggest that tumor necrosis factor-alpha and interferon-gamma inhibit hepatitis B virus replication by blocking some step in reverse transcription and that the 2',5'-oligoadenylate synthetase is not involved in the mechanism underlying the inhibition by these two cytokines.

The value of quantitative measurement of HBeAg and HBsAg before interferon-alpha treatment of chronic hepatitis B in children

Serum concentrations of HBsAg, HBeAg and hepatitis B virus DNA were measured quantitatively before interferon treatment in 23 children (17 boys, 6 girls) suffering from chronic hepatitis B, and correlated to the outcome of the treatment. Five children remained HBsAg- and HBeAg-positive throughout the treatment and 6 months after the end of the treatment (non-responders), 12 children eliminated HBeAg but not HBsAg (partial responders) and six eliminated HBeAg and HBsAg (complete responders). The five non-responders had significantly higher initial HBsAg and HBeAg concentrations and significantly lower alanine aminotransferase levels than the partial or complete responders. The six complete responders had significantly lower HBsAg concentrations than the partial or non-responders, and seemed to be younger. No significant difference in HBV DNA levels was found in the three response groups. These data suggest that quantitative assays of HBsAg and HBeAg are particularly useful in selecting patients with chronic hepatitis B for interferon therapy.

Treatment of chronic hepatitis B

Chronic infection with the hepatitis B virus (HBV) is a major cause of worldwide morbidity and mortality. A large number of therapeutic approaches has been tried, including interferon (IFN), nucleoside analogues and immunomodulators. To date controlled clinical trials have shown that only IFN is of long-term value but many patients fail to respond to treatment. New approaches to treating patients with IFN-resistant hepatitis B are currently undergoing clinical and experimental evaluation, and it seems likely that new therapeutic agents will be available in the near future.

Cytokines in the treatment of virus infections

The interferon (IFN) system consists of both the formation of the various IFN proteins, and the diverse cellular responses which these induce: these result from the intracellular changes which follow their binding to a specific cell surface receptor. There is only a single human gamma, omega and beta IFN; in contrast, there are 13 closely related chemical species ("subtypes") of human alpha IFN, which are nevertheless chemically and biologically distinct. IFN preparations made from mass cultured human cells or by using recombinant DNA techniques are now readily available for clinical use. IFN have a major role in the defence of the body against virus infections. In acute virus infections, preformed exogenous IFN cannot be given soon enough to be of value. However, IFN-alpha and IFN-beta have proved of considerable value in some chronic virus infections, particularly chronic virus hepatitis and chronic papillomavirus infections. The doses routinely used are associated with both acute and chronic toxic side effects. Also, some patients form specific neutralising antibodies against the particular IFN preparation injected, which may abrogate all the benefits of the treatment. Nevertheless, IFN are now established as agents for use in routine medical practice.

Treatment of chronic viral hepatitis

Recent advances have been made in the treatment of chronic viral hepatitis, mainly with recombinant interferon (IFN) alpha. However, the present treatment of chronic viral hepatitis is not entirely satisfactory because the efficacy is inconstant and/or incomplete. In chronic hepatitis B IFN-alpha induces a sustained interruption of hepatitis B virus (HBV) replication, with a HBeAg to anti-HBe seroconversion in about 30% of patients. Patients most likely to respond are those with no immunosuppression, HBV infection acquired during adulthood or active liver disease with low HBV replication. Responders usually show a significant decrease in serum HBV DNA levels during the first 2 months of therapy, followed by a significant increase in the level of aminotransferases. New nucleoside analogues might be useful in combination with IFN-alpha in the treatment of those who do not respond to IFN therapy. In chronic hepatitis B-D, the rate of sustained response to IFN-alpha therapy is low. To be effective, IFN-alpha must be used at a high dosage (9-10 mega units) with a long duration (1 year). In chronic hepatitis C, IFN-alpha at a dosage of 3 mega units over 6 months, induces a sustained response in about 20% of patients. A higher dosage of IFN (5-10 mega units) and a longer duration of treatment increases the rate of sustained response but is associated with poor tolerance. Non-responders to a first course of IFN do not respond to a second course of treatment. In patients who respond but relapse after treatment, the rate of sustained response after a second course of IFN needs to be assessed. Ribavirin, which has a significant antiviral effect on hepatitis C virus, might be useful in combination with IFN-alpha. At the dosage (3-6 mega units) usually used, IFN-alpha is relatively well tolerated. In about 10% of the patients therapy is interrupted, mainly because of severe fatigue, thyroid dysfunction or depression.

Induction of autoimmune phenomena in patients with chronic hepatitis B treated with gamma-interferon

All interferons display antiviral properties, but gamma-interferon especially has an immunomodulatory effect and may induce autoimmune phenomena. Therefore the formation of autoantibodies was investigated in patients with chronic hepatitis B treated with gamma-interferon. Eleven patients (all HBs-Ag and HBe-Ag positive) were treated for 6 months with recombinant gamma-interferon. The following antibodies were tested: anti-nuclear antibodies, smooth muscle antibodies, anti-actin, anti-mitochondrial antibodies of subgroup anti-M2 and anti-M9 as well as naturally occurring antibodies, antibodies to liver-kidney microsomes, vascular endothelial cell antibodies, sarcolemmal antibodies, parietal cell antibodies, thyroglobulin antibodies and antibodies to laminin and keratin. All patients produced autoantibodies during therapy. The maximum antibody formation and the highest titres were observed in the period between the 3rd and 6th month after therapy began. The cumulative frequencies of the different antibody specificities were as follows: n = 6 anti-nuclear antibodies, n = 7 smooth muscle antibodies, n = 1 anti-actin, n = 12 antibodies to laminin or keratin, n = 6 endothelial cell antibodies/sarcolemmal antibodies, n = 6 anti-mitochondrial antibodies, n = 1 antibodies to liver-kidney microsomes, n = 2 thyroglobulin antibodies, n = 4 parietal cell antibodies. Antibodies persisted in six patients over a period of 3 months (two cases of parietal cell antibodies and one case of antibodies to liver-kidney microsomes) and were still detectable in three patients 6 months after therapy. In three patients new antibody formation occurred 1 month after therapy. So far, clinical signs of an autoimmune disorder have not appeared in any of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B virus infection in schistosomiasis mansoni

Schistosomiasis and hepatitis B virus (HBV) infection are very common in Brazil but the interrelationships between the two infections are poorly understood. We have undertaken a detailed serological study of the prevalence of HBV markers in 189 Brazilian patients with chronic schistosomiasis mansoni, 46 with hepatointestinal (HIS) and 143 with hepatosplenic (HSS) schistosomiasis, 12 of the latter having decompensated liver disease (HSSD), and in 50 control patients. Sera were tested for HBsAg, anti-e, anti-HBc, anti-HBs and HBV-DNA. Eighty-three (44%) of the 189 schistosoma patients had at least one marker of HBV infection, 18 of whom (10%) were seropositive for HBsAg. All the controls were HBsAg negative, but ten (20%) had anti-HBc and anti-HBs. There was no significant difference in the frequency of these markers between HIS (14/46, 30.4%), HSSC (43/131, 34.5%), and the controls. Among the HBsAg-positive patients, one had HIS (HBV-DNA negative), seven had HSSC (one HBV-DNA positive) and ten had HSSD (six HBV-DNA positive), a significant association of HBV carriage with HSSD (P << 0.001). Mean (+/- SD) ALT values were significantly (P < 0.001) higher in HBsAg-positive HSSD patients (70.7 +/- 18 IU/liter) than in those with HSSC (29.5 +/- 15 IU/liter). Liver biopsies were performed in 12 HBsAg-positive patients (one with HIS, three with HSSC, and eight with HSSD) and in 50 HBsAg-negative HSSC patients. Seven of the eight HSSD patients had chronic active hepatitis with cirrhosis, and one had inactive cirrhosis. All three patients with HSSC and the one with HIS had chronic persistent hepatitis, with periportal fibrosis in three.(ABSTRACT TRUNCATED AT 250 WORDS)

New approaches to the treatment of chronic viral hepatitis B and C

Interferon treatment of hepatitis B and C virus (HBV, HCV) infections has been hampered by overall initial response rates of < 50%, a relapse rate that is > 50% for patients with chronic HCV, and rare responses in individuals with chronic HBV who are immunosuppressed or immunologically tolerant to the HBV. Because of these difficulties, the efficacy of other therapeutic agents is being vigorously explored. Among the immunomodulatory agents being evaluated, thymosin appears to be a promising new therapy for HBV. Results from an ongoing multicenter trial evaluating thymosin are expected next year. A variety of nucleoside analogues with antiviral activity against the HBV have also been identified. Several of the more active agents deserve further study in clinical trials. In chronic HCV infection, only interferon therapy has been extensively studied. Ribavirin alone may have some value, but its precise role in the treatment of chronic HCV will require additional testing. Interferon therapy for patients with chronic HBV or HCV infection represents an important first step in the treatment of these disorders. In the absence of an ideal antiviral agent, however, combinations of the available antiviral and immunomodulatory agents or synergistic combinations of antiviral agents need to be studied in order to achieve better therapeutic responses.

The effect of interferon alpha and prednisolone on the serum concentrations of the aminoterminal domain of procollagen type III(PIIIP) and type IV (7-S collagen) in patients with chronic hepatitis B

Since interferons are reported to inhibit collagen synthesis in vivo and in vitro, they are possible anti-fibrogenic drugs. However, little is known about the effect of interferons on connective tissue metabolism in liver disease. To investigate the effect, serum concentrations of the aminoterminal domain of procollagen type III and type IV (7-S collagen) were measured in 16 patients with chronic hepatitis B during alpha interferon treatment. The levels were also determined during prednisolone withdrawal treatment to investigate the effect on hepatic collagen turnover. In patients with chronic hepatitis B, the serum levels of both markers were significantly elevated before any treatment (procollagen type III: 1.10 +/- 0.39 U/ml, 7-S collagen: 6.69 +/- 3.71 ng/ml) compared with levels in 41 healthy volunteers (pro-collagen type III: 0.53 +/- 0.13 U/ml, P < 0.001; 7-S collagen: 4.72 +/- 0.57 ng/ml, P < 0.001). Both levels were even more elevated during interferon therapy (procollagen type III: 1.36 +/- 0.58 U/ml, P < 0.05; 7-S collagen: 8.77 +/- 4.68 ng/ml, P < 0.01). On the other hand, serum procollagen type III and 7-S collagen levels were both decreased during prednisolone treatment (procollagen type III: 0.62 +/- 0.13 U/ml, P < 0.001; 7-S collagen: 4.66 +/- 1.69 ng/ml, P < 0.01). These preliminary data suggest that interferon alpha enhanced, but prednisolone inhibited the turnover of procollagen type III and IV in the liver. Further study is required to interpret this observation in relation to anti-fibrotic therapy.

Interferon alfa for patients with clinically apparent cirrhosis due to chronic hepatitis B

BACKGROUND

The prognosis of advanced cirrhosis due to chronic hepatitis B is poor, and results of therapies, including liver transplantation, have been unsatisfactory. Little is known about the effectiveness of interferon alfa in patients with cirrhosis.

METHODS

Between 1984 and 1991, 18 patients with clinically-apparent cirrhosis due to hepatitis B were treated with interferon alfa at the Clinical Center of the National Institutes of Health.

RESULTS

Six treated patients (33%) had a sustained loss of hepatitis B virus DNA and hepatitis B e antigen (if present initially) and decrease of amino-transferase levels into the normal or near normal range. In follow-up, these 6 patients resolved all symptoms of cirrhosis and are alive and fully active. In contrast, the 12 patients who did not have a sustained loss of hepatitis B virus have had evidence of progressive liver disease, 6 have died and 4 underwent hepatic transplantation. Side effects of interferon were common and included bacterial infections (n = 5) and exacerbations of disease (n = 9).

CONCLUSIONS

These findings indicate that interferon alfa is effective in selected patients with mildly decompensated cirrhosis due to hepatitis B.

Alpha- and gamma-interferon versus alpha-interferon alone in chronic hepatitis B. A randomized controlled study

Thirty-two patients with chronic hepatitis B were randomly assigned to two groups. Sixteen patients received 10 million units of alpha-interferon per square meter of body surface (MU/m2), three times weekly for 4 months. Sixteen patients were treated simultaneously with gamma-interferon at a dose of 2 MU/m2, and 10 MU/m2 of alpha-interferon. At the end of the study (13th month), hepatitis B virus DNA was negative in 50% of the patients treated with alpha-interferon and in only 25% of those treated with alpha- and gamma-interferon. A similar trend was observed with respect to the hepatitis B e antigen negativization (31% and 19% of HBeAg negativization in patients treated with alpha- and gamma-interferon, respectively). In summary, these data demonstrate that, at the doses used in this study, the combination of alpha- and gamma-interferon does not give better results than the administration of alpha-interferon alone. The tolerance to simultaneous alpha- and gamma-interferons is poor and may decompensate the liver disease.

Repeated courses of alpha-interferon for treatment of chronic hepatitis type B

In chronic hepatitis B transition from active replication to viral latency (HBeAg seroconversion) usually leads to remission of the disease. alpha-Interferon (IFN) therapy induces HBeAg seroconversion in about one-third of the patients, thus leaving the majority of patients with persistent disease. Eighteen chronic hepatitis B patients who did not respond (HBeAg seroconversion and clearance of HBV-DNA) to an initial 16-week course of IFN subsequently received IFN again after at least 6 months of no therapy. The repeated therapy consisted of 1.5-5 MU lymphoblastoid IFN daily for 16 weeks. Treatment effects were monitored by quantitative measurement of HBeAg and HBV-DNA. To analyze whether the results were related to patient characteristics known to affect the response to initial treatment, a predicted response rate, based on pre-treatment factors, was determined. After a follow-up of 52 weeks, 2 of the 18 patients (11%) had responded to therapy. Two additional patients became HBV-DNA-negative with sustained HBeAg positivity. All patients remained HBsAg-positive. According to the pre-treatment parameters, a response was predicted for 9 of the 18 patients (50%). This predicted response rate was significantly higher than the actual response rate (p = 0.03). In conclusion, this pilot study with moderate dosages of IFN suggests that the HBeAg seroconversion rate after repeated IFN treatment is low for previous non-responders and probably is not related to important clinical characteristics that influence the response to initial IFN treatment. A large controlled trial with higher doses of IFN is desirable to further evaluate the benefits of retreatment.

Interferon-gamma receptor expression in chronic hepatitis B virus infection

It is known that interferon-gamma (IFN gamma) is not effective in inducing a sustained inhibition of HBV replication in patients with chronic HBV infection in contrast to interferon-alpha (IFN alpha). To determine whether this was related to IFN gamma receptor (IFN gamma-R) underexpression, binding characteristics of IFN gamma to peripheral blood lymphocytes were studied in chronic HBV infection using radioiodinated recombinant IFN gamma. Peripheral blood lymphocytes from patients with chronic HBV infection (n = 20), normal healthy controls (n = 12) and patients with non-viral related chronic liver disease expressed a similar number of IFN gamma-R (medians (ranges): 1891 (1581-2515); 1916 (1589-2441); 1893 (1692-2104) sites/cell, respectively, p = N.S.) with a similar dissociation constant (Kd approximately 0.7-2.7 nM). There was no correlation between IFN gamma-R expression and serum transaminase, serum HBsAg and HBV-DNA titres and liver histology. IFN alpha therapy in vivo also did not enhance IFN gamma-R expression (n = 3). There is therefore, no evidence from this data that IFN gamma-R is underexpressed in patients with chronic HBV infection to account for the difference in clinical response to these two forms of therapy.

Antifibrotic and uveitogenic properties of gamma interferon in the rabbit eye

The feasibility of gamma (gamma)-interferon injection for the treatment of ocular fibrotic conditions was studied in rabbits using recombinant rabbit gamma-interferon and the cell-injection model of tractional detachment. A toxicity study revealed that intravitreal injection of greater than 10(4) units gamma-interferon consistently produced panuveitis. For tractional detachment, 250,000 rabbit dermal fibroblasts were injected intravitreally into 20 eyes; 1 day later, 5 of these eyes received intravitreal injections of 10(4) units gamma-interferon, another 5 were given 10(6) units, and the remaining 10 received balanced salt solution. Slit-lamp examination and fundus photography were performed at regular intervals for 21 days and were graded by a masked observer. The eyes were then enucleated and processed for histology. Doses of 10(4) units gamma-interferon significantly reduced the severity of detachments, but injections of 10(6) units induced panuveitis.

Therapies for hepatitis B virus: current status and future possibilities

Alpha-interferon is the first agent with proven therapeutic efficacy in humans with chronic HBV infection. Obviously, further research is needed to clarify and expand the role of interferon in this setting. In addition, an overall response rate of less than 50% illustrates the need for continuing innovation in the treatment of HBV infection especially in patients with predictors of poor outcome. Despite the advent of effective vaccines against HBV, this pathogen is likely to remain a source of serious human morbidity and mortality for the foreseeable future. Continuing efforts must be directed towards finding more effective therapies against HBV. A recent preliminary report suggests that thymosin. like interferon on immune modulator, may also be efficacious in the treatment of chronic HBV and deserves further study.

Effect of interferon-gamma on hepatitis B viral antigen expression in primary hepatocyte culture

Interferon-alpha has been shown recently to selectively enhance hepatocyte expression of HBsAg/pre-S2 in chronic hepatitis B virus infection in a way that may enhance immune recognition. To determine the effect of interferon-gamma on hepatitis B virus antigen expression, hepatocytes isolated from patients with chronic hepatitis B virus infection were incubated in the absence or presence of interferon-gamma and viral antigen expression was assessed by both radioimmunoassay and immunocytochemistry using appropriate monoclonal antibodies. Interferon-gamma inhibited the expression of all hepatitis B virus antigens tested. Intracellular HBsAg measured by radioimmunoassay of sonicated hepatocytes fell by 29% with 1 U/ml (p less than 0.01) and 36% with 10 U/ml of interferon-gamma (p less than 0.001) compared with control treatment. Secreted HBsAg was reduced by 19% with 10 U/ml of interferon-gamma (p less than 0.01). Intracellular HBeAg was also decreased by 29% with 1 U/ml (p less than 0.05) and 42% with 10 U/ml of interferon-gamma (p less than 0.05), but no significant change was found in the amount of secreted HBeAg. The proportion of hepatocytes containing various hepatitis B virus antigens and the intracellular viral antigen staining densities also fell significantly with interferon-gamma incubation. Interestingly, the addition of interferon-gamma abolished the augmenting effect of interferon-alpha on intracellular HBsAg. These data indicate that interferon-gamma, in contrast to interferon-alpha, has an inhibitory effect on hepatocyte expression of all hepatitis B virus antigens including HBsAg/pre-S2, suggesting that this may be one factor that accounts for their difference in clinical activity in patients with chronic hepatitis B virus infection.

Treatment with human gamma interferon of chronic hepatitis B: comparative study with alpha interferon

A pilot study was designed to determine the tolerance and effectiveness of natural or recombinant gamma interferon in patients with chronic hepatitis B. Sixteen patients received 0.5 to 3.0 million units (MU) per day of gamma interferon (IFN-gamma) for 7 days. Nineteen chronic hepatitis B patients who were treated with 5-6 MU leukocyte-derived alpha interferon (IFN-alpha) daily served as controls. All completed the treatment schedule. IFN-gamma exerted mild, but significant inhibitory effects (P less than .05) on serum DNA polymerase levels. However, the changes were significantly less (P less than .001) than those seen with IFN-alpha therapy when compared with percent change from basal values. In contrast, serum 2', 5'-oligoadenylate synthetase (2-5 AS) activities were markedly enhanced to a similar extent during therapy with both IFNs. Serum beta 2-microglobulin values were significantly increased by administration with both IFNs, although higher values were seen with IFN-gamma. Five patients received 1 MU IFN-gamma for 28 consecutive days and their HBeAg levels similarly decreased as those seen in patients treated with IFN-alpha. Side effects seemed to be greater during IFN-gamma therapy than IFN-alpha despite the lower doses used. The antiviral effect on serum HBV levels appeared less with IFN-gamma than with IFN-alpha. Alternatively immunomodulatory functions may have been enhanced with IFN-gamma in patients with chronic HBV infection.

A randomised controlled trial of recombinant interferon-gamma in Chinese patients with chronic hepatitis B virus infection

Nineteen Chinese patients with chronic hepatitis B virus (HBV) infection, seropositive for HBV e antigen (HBeAg) and HBV DNA on at least three occasions in 6 months, were randomised to receive either recombinant human interferon-gamma (rIFN gamma) 0.1 mg/m2 intramuscularly thrice weekly for 16 weeks (n = 11) or no anti-viral therapy (controls, n = 8). Five patients in the treatment group and four patients in the control group had persistently elevated serum alanine aminotransferases (ALT) of over two times the upper limit of normal before entering into the trial. rIFN gamma had no or minimal inhibitory effect on serum HBV DNA during treatment and no patient developed e-seroconversion or sustained loss of serum HBV DNA. Hepatitic flare, which occurred in a proportion of patients responding successfully to interferon-alpha (IFN alpha) therapy, was not observed with rIFN gamma treatment. Side-effects included pyrexia and mild headache that showed tachyphylaxis and were well tolerated by all patients. In the control group, one patient with elevated pre-entry serum ALT lost serum HBV DNA and seroconverted to anti-HBe. Another patient with elevated ALT lost serum HBV DNA transiently during therapy. In the dose given, rIFN gamma was safe but had no apparent anti-viral effects in Chinese patients with chronic HBV infection.

Effect of interferon administration on serum hepatitis C virus RNA in patients with chronic hepatitis C

Hepatitis C virus RNA as detected by reverse transcription and nested polymerase chain reaction was monitored in 16 patients with chronic hepatitis C treated with interferon. Hepatitis C virus RNA became undetectable after 4 to 8 wk of interferon administration in 13 of the 16 patients. During 6 mo of follow-up, 5 of the 13 patients who became negative for hepatitis C virus RNA after interferon administration remained negative, and all five continued to have normal ALT levels. Repeat liver biopsy in these five patients revealed histological improvement. Antibody to hepatitis C virus, which was initially positive in all treated patients, fell to undetectable levels in three of the five patients. In contrast, aminotransferase levels rose again in all eight patients who had become hepatitis C virus RNA negative but had again exhibited hepatitis C virus RNA after completion of therapy. In 16 untreated patients, hepatitis C virus RNA remained detectable. These results indicate that detection of hepatitis C virus RNA may be useful as a marker of viral replication in chronic hepatitis C; they also suggest that interferon should again be administered to patients who become hepatitis C virus RNA negative on treatment but again exhibit this marker of viral replication when treatment is stopped.

Is there an alternative to alpha-interferon in chronic hepatitis B?

At present immune-based therapies are not an alternative to alpha-interferon in the treatment of chronic hepatitis B. Patients who do not respond to alpha-interferon should probably be followed without re-treatment. Re-treatment using a short course of prednisone before alpha-interferon deserves further study. Future investigation of immune-based therapies should be done in the context of available antiviral therapies. Alternatives need to be propounded and tested, especially alternatives that cause us to question assumptions and to rethink our current beliefs about chronic HBV immunopathogenesis.