A practical guide to the use of interferons in the management of hepatitis virus infections

A functional polymorphism in ADAR1 gene affects HBsAg seroclearance both spontaneously and interferon induced

BACKGROUND & AIMS

Our previous study found that rs4845384 in ADAR1 gene to be associated with HBeAg seroconversion. However, the effect of rs4845384 on HBsAg seroclearance is unknown. To assess the relationship between rs4845384 and HBsAg seroclearance.

METHODS

Two independent case-control studies were conducted to test whether rs4845384 in ADAR1 was associated with HBsAg clearance. Reporter gene assays and quantitative PCR experiments were also carried out to verify the functional significances of this polymorphism.

RESULTS AND CONCLUSIONS

The rs4845384 polymorphism was associated with HBsAg seroclearance both spontaneously (P = 0.028, OR = 1.36, 95% CI = 1.03-1.78) and interferon induced (P = 0.013, OR = 1.83, 95% CI = 1.13-2.96), in a total of 725 subjects. Luciferase assays showed that pGL3-rs4845384G constructs had higher expression level than pGL3-rs4845384A constructs, especially in HepG2. 2.15 cell line. Quantitative real-time RT-PCR showed that chronic hepatitis B (CHB) patients had lower ADAR1 mRNA level than healthy individuals. The AA carriers of rs4845384 had lower ADAR1 mRNA expression than non-AA carriers. The non-response susceptible allele rs4845384A was functional for regulation of ADAR1 expression, so as to influence HBsAg seroclearance of CHB patients.

JAK1 gene polymorphisms are associated with the outcomes of hepatitis B virus infection, but not with α interferon therapy response in a Han Chinese population

AIMS

Janus kinase 1 (JAK1) is a key member in the interferon (IFN) signaling pathway. Recent studies suggested single-nucleotide polymorphisms (SNPs) in IFN pathway genes are associated with outcomes of hepatitis B virus (HBV) infection and response to IFNα therapy. The aim of the study is to investigate whether SNPs in JAK1 were associated with outcomes of HBV infection and response to IFNα therapy.

METHODS

We enrolled 395 chronic hepatitis B (CHB) patients and 251 subjects with the inactive carrier state, and 256 CHB patients who received IFNα treatment, with therapy efficacy evaluated. Twelve SNPs: rs310227, rs7531799, rs7546545, rs17127174, rs3790541, rs10493373, rs2780898, rs310247, rs310196, rs2780895, rs4244165, and rs17127024 in JAK1, which could represent all SNPs with minor allele frequency >0.2 recorded in the HapMap database were genotyped using a polymerase chain reaction-restriction fragment length polymorphism protocol and the TaqMan method.

RESULTS

SNP rs17127024 was associated with outcomes of HBV infection in an allele frequency (p=0.014) and genotype distributions (p=0.031), while SNP rs4244165 was associated with outcomes of HBV infection only in genotype distributions (p=0.008). There were no significant differences in allele frequencies and genotype distributions of these SNPs between the response group and the nonresponse group to IFNα therapy.

CONCLUSIONS

SNPs rs4244165 and rs17127024 in JAK1 were associated with outcomes of HBV infection, but not with response to IFNα therapy.

Polymorphisms in ADAR1 gene affect response to interferon alpha based therapy for chronic hepatitis B in Han Chinese

Host genetic polymorphisms in interferon pathway genes are reported to be associated with response to interferon therapy. Five hundred and forty-eight α interferon treatment-naïve chronic hepatitis B patients were enrolled in the retrospective nested case-control study. All patients received α interferon based treatment and were examined for therapy efficacy. We genotyped 115 polymorphisms from 16 interferon pathway genes using the MassArray system. We identified rs4845384 in ADAR1 gene is strongly associated with the outcome of interferon therapy allele dose-depended (P=0.0005), with decreased odds ratios of 0.69 and 0.27 for GA and AA genotypes, respectively (95% confidence interval, 0.47-0.99 for GA; 0.11-0.64 for AA). Our study suggested that rs4845384 in ADAR1 associates with treatment-induced clearance of chronic hepatitis B.

Human leukocyte antigen class I and class II genes polymorphisms might be associated with interferon α therapy efficiency of chronic hepatitis B

Certain host genetic polymorphisms in human leukocyte antigen (HLA) genes are reported to be associated with response to interferon α (IFNα) therapy. Two hundred and eighteen IFNα treatment-naïve chronic hepatitis B (CHB) patients were enrolled in the present study. HLA-A, B, C and DQA1, DQB1, DRB1 gene alleles were detected by polymerase chain reaction-sequencing based typing (PCR-SBT) and PCR-sequence specific primer (PCR-SSP), respectively. Frequencies of HLA-DQB1*0303 and DRB1*08 in response group were clearly lower than those in nonresponse group (P=0.019, OR=1.81, 95%CI=1.07-3.15; P=0.031, OR=2.43, 95%CI=1.02-5.98, respectively). Frequencies of haplotype *1101-*4601-*0102 (HLA-A, B, C) and haplotype *0302-*0303-*09 (HLA-DQA1, DQB1, DRB1) were clearly lower than those in nonresponse group (P=0.009, OR=4.84, 95%CI=1.29-19.48; P=0.031, OR=1.94, 95%CI=1.01-3.73, respectively). These results suggest that patients with HLA-DQB1*0303 or DRB1*08 alleles, and haplotype *1101-*4601-*0102 (HLA-A, B, C) or haplotype *0302-*0303-*09 (HLA-DQA1, DQB1, DRB1), might be less responsive to IFNα treatment.

Drug delivery systems and liver targeting for the improved pharmacotherapy of the hepatitis B virus (HBV) infection

In spite of the progress made in vaccine and antiviral therapy development, hepatitis B virus (HBV) infection is still the most common cause of liver cirrhosis and hepatocellular carcinoma, with more than 400 million people chronically infected worldwide. Antiviral therapy with nucleos(t)ide analogues and/or immunomodulating peptides is the only option to control and prevent the progression of the disease in chronic hepatitis B (CHB)-infected patients. So far, the current antiviral monotherapy remains unsatisfactory because of the low efficacy and the development of drug resistance mutants. Moreover, viral rebound is frequently observed following therapy cessation, since covalent closed circular DNA (cccDNA) is not removed from hepatocytes by antiviral therapy. First, this review describes the current pharmacotherapy for the management of CHB and the new drug candidates being investigated. Then, the challenges in the development of drug delivery systems for the targeting of antiviral drugs to the liver parenchyma are discussed. Finally, perspectives in the design of a more efficient pharmacotherapy to eradicate the virus from the host are addressed.

Evaluation of antiviral activity and toxicity of recombinant human interferon alfa-2a in calves persistently infected with type 1 bovine viral diarrhea virus

OBJECTIVE

To evaluate antiviral activity and toxicity of recombinant human interferon alfa-2a in calves persistently infected with noncytopathic type 1 bovine viral diarrhea virus (BVDV).

ANIMALS

5 Holstein heifers, 4 to 12 months of age.

PROCEDURES

Calves persistently infected with noncytopathic type 1 BVDV were treated with recombinant human interferon alfa-2a every other day for 12 weeks. Viral loads were measured during the treatment period and compared with pre- and post-treatment values. Complete physical examinations were performed weekly, and calves were observed daily for signs of systemic illness. Complete blood counts and serum biochemical analyses were performed before, during, and after the treatment period. Because calves developed anemia during the treatment period, bone marrow biopsy specimens were collected. Antirecombinant human interferon alfa-2a antibody concentrations in serum samples obtained before, during, and after the treatment period were measured by use of an ELISA.

RESULTS

Recombinant human interferon alfa-2a had no antiviral activity against noncytopathic type 1 BVDV in persistently infected calves. All calves developed microcytic anemia during the treatment period that persisted for up to 13 weeks after cessation of treatment. Anti-interferon antibodies were detected during the treatment period and persisted for at least 2 weeks after cessation of treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Because of lack of in vivo antiviral activity against BVDV, recombinant human interferon alfa-2a has little promise as a therapeutic agent for the treatment of BVDV infection, at least in persistently infected cattle. Furthermore, treatment was associated with adverse immunologic and hematologic effects.

Current therapeutic approaches in childhood chronic hepatitis B infection: a multicenter study

BACKGROUND AND AIM

The aim of the present study was to compare the therapeutic efficacy of three different regimens in childhood chronic hepatitis B (CHB) infection.

METHODS

A total of 182 children with CHB infection were prospectively allocated to three random groups. Sixty-two patients in the first group received high-dose interferon (IFN)-alpha 2b (10 MU/m2) thrice/weekly alone for 6 months. In the second (n = 60) and third groups (n = 60), IFN-alpha was used for 6 months (5 MU/m2) thrice/weekly in combination with lamivudine (LAM) (4 mg/kg, maximum 100 mg/day) for 12 months. Lamivudine was started simultaneously with IFN in the second group, while it was started 2 months prior to IFN injections in the third group.

RESULTS

The initial mean alanine aminotransferase (ALT) values for the first, second and third groups were 109 +/- 93 IU/L, 101 +/- 64 IU/L and 92 +/- 42 IU/L, respectively (P > 0.05). At the end of the therapy, ALT values decreased to 82 +/- 111 IU/L, 38 +/- 41 IU/L and 29 +/- 16 IU/L in groups 1, 2 and 3, respectively. The mean ALT value of the first group was significantly different to the second and third groups (P = 0.046 and P = 0.002, respectively) at the end of the therapy and these differences were found to be sustained after 18 months. However, results in the second and third groups were similar (P > 0.05). There were no significant differences in HBeAg clearance and anti-HBe seroconversion at the initial stage, 12 months and 18 months between the three groups (P > 0.05). Hepatitis B virus (HBV) DNA clearance in the first group was different from the second and third groups, while the second and third groups had similar HBV DNA clearance ratios at 12 and 18 months. No significant difference was found in the complete response (normalization of ALT, clearance of HBV DNA and seroconversion of anti HBe) ratios of all groups (at 12 months: 28.8, 45.5, 35.8% and at 18 months 33.3, 49 and 34% in groups 1, 2 and 3, respectively, P > 0.05).

CONCLUSIONS

Although the ALT normalization and HBV DNA clearance ratios of IFN plus LAM combination groups were better than the high-dose IFN-alpha monotherapy group, no significant difference was found in the complete response ratios of all three groups.

Quality of life in HCV-infection: lack of association with ALT levels

OBJECTIVES

To examine the impact of HCV infection in an Australian clinic population and identify the relationships between morbidity, psychosocial variables and one clinical indicator of HCV activity, alanine aminotransferase (ALT).

METHOD

Ninety-five untreated HCV-infected patients (21-69 years) in infectious and liver diseases clinics who were all positive for HCV-RNA and had no significant comorbidities or coinfections completed a survey containing the Short Form 36 (SF36), as well as the six-item Social Support Questionnaire (SSQ6), demographic items and questions concerning respondents' perceptions of their mode and duration of infection. Nine volunteers from this group participated in semi-structured qualitative interviews aimed at exploring the social impact of HCV status. These data were compared with serum ALT levels. SF36 scores were compared to population norms and according to participant variables.

RESULTS

Mean SF36 scores were significantly lower, across all modalities, than population norms. SF36 scores differed significantly according to age, sex, mode of infection, alcohol and methadone use, and satisfaction with social support. They did not differ significantly according to perceived or actual ALT level or pattern of ALT activity. Worry about ALT was prevalent (>50%) and this was independent of perceived ALT level.

CONCLUSIONS AND IMPLICATIONS

HCV-infection is associated with significantly reduced quality of life and includes the perception of substantial social discrimination. ALT levels are of limited usefulness in ascertainment of a person's sense of wellbeing and quality of life in HCV-infection. Increased support and information for affected individuals and measures aimed at countering social discrimination are important recommendations of the current study.

Combination chemotherapy for hepatitis B virus: the path forward?

Hepatitis B virus (HBV) was identified as a cause of viral hepatitis more than 30 years ago and hepatitis B vaccines have been available for almost 20 years, but HBV infection continues to be a global health problem, responsible for about 1.2 million deaths annually. By the end of this year, almost 400 million people--about 5% of the world's population and more than ten times the number infected with human immunodeficiency virus (HIV)--will be infected with HBV. Chemotherapy remains the only treatment option for controlling chronic HBV infection once acquired, but none of the many different chemotherapeutic strategies used in the past has proven consistently successful. Prospects for successful treatment of HBV have improved dramatically during the past decade due to the development of new, well tolerated and efficacious anti-HBV drugs, and to advances in our understanding of HBV replication and pathogenesis. The newer anti-HBV drugs are capable of reducing viral loads very rapidly, but the initial response is invariably followed by very much slower elimination of residual virus. As more effective anti-HBV drugs become available, the emergence of drug resistance during the slower phase of HBV elimination will probably become the most significant obstacle in the way of eventual control of HBV infection. Experience with HIV indicates that combination chemotherapy may suppress or eliminate drug resistance and methods for pre-clinical and clinical assessment of anti-HBV drug combinations are being developed. Basic research into mechanisms of drug action and interaction should assist in the design and optimisation of combination chemotherapy for HBV infection, for which additional new anti-HBV drugs will undoubtedly be required in future.

Genotype and viral load as prognostic indicators in the treatment of hepatitis C

Interferon-alpha (IFN-alpha), either alone or in combination with ribavirin, is the standard treatment for patients with hepatitis C. However, most patients do not achieve a sustained remission with this treatment regimen. A number of studies have demonstrated that genotype, baseline viral load and/or a decrease in viral load early after treatment induction are the major predictive factors for response to treatment with IFN. Patients with hepatitis C virus (HCV) genotype 1 are more resistant to treatment with IFN, whereas low viral load at baseline and a marked decline in the HCV RNA level during the first 2-12 weeks of IFN therapy are associated with enhanced treatment efficacy. These variables could potentially be used to develop treatment algorithms that tailor therapies for specific clinical situations. Continued development and refinement of such algorithms would facilitate both the selection of patients who are most likely to benefit from therapy and the development of optimal treatment regimens for different patient groups. Predictive factors will also enable clinicians to identify subsets of patients who are not expected to respond well to current treatment. The development of new delivery methods for IFN that produce sustained antiviral pressure may provide a means of treating these previously difficult-to-treat patient groups.

The cross-species antiviral activities of different IFN-tau subtypes on bovine, murine, and human cells: contradictory evidence for therapeutic potential

It is claimed that interferon-tau (IFN-tau) has broad cross-species reactivity and less cytotoxicity than other type I IFN when used at high concentration either in vitro or in living animals. It can also amelioriate the development of experimental allergic encephalomyelitis (EAE) without the usual side effects of IFN therapy in mice autoimmunized with myelin basic protein. For these reasons, IFN-tau may have therapeutic potential in humans. Here, the antiviral (AV) activities of eight different recombinant IFN-tau were compared with those of several bovine, human, and murine type I IFN on bovine MDBK cells, murine L929 cells, and human WISH cells. The data show that only one of the IFN-tau, OvIFN-tau4, has broad cross-species reactivity. It was comparable in this respect to HuIFN-omega1 and HuIFN-alpha1. The other IFN-tau, including the variant form (OvIFN-tau1mod) tested by others in cytotoxicity experiments and for its ability to protect mice against EAE, had relatively weak AV activity on mouse and human cells. It is possibly because this particular bioengineered form of IFN-tau binds the common type I receptor of these two species with such low affinity that it lacks cytotoxic effects. The basis for its potent anti-EAE activity is unclear, but it seems possible that it does not involve the type I IFN receptor.

Role of lamivudine in the treatment of chronic hepatitis B virus infection

OBJECTIVE

To examine the evidence regarding the therapeutic effectiveness of lamivudine in the treatment of chronic hepatitis B virus (HBV) infection in immunocompetent patients.

DATA SOURCES

Using chronic hepatitis B and lamivudine as MeSH headings, MEDLINE was searched from 1966 to September 1998 for all published randomized controlled trials evaluating lamivudine in chronic HBV infection. Relevant articles from selected bibliographies were also retrieved.

STUDY SELECTION

Only randomized, single- and double-blind trials in human HBV carriers published in the English language were included.

DATA SYNTHESIS

Evidence from the controlled trials suggests that lamivudine has a therapeutic effect in suppressing HBV replication in immunocompetent patients. Lamivudine 100 mg/d appears to suppress HBV replication in as many as 97% of patients within two weeks after the initiation of therapy and is capable of suppressing histologic damages. However, viral suppression is effective only during the therapy; on discontinuation of lamivudine therapy, most patients return to the pretreatment condition. Viral resistance to lamivudine has been observed. Most patients with chronic HBV infection appear to tolerate 100 mg/d of lamivudine therapy.

CONCLUSIONS

Evidence has shown that oral lamivudine 100 mg/d will produce rapid and significant suppression of viral replication in immunocompetent patients with chronic HBV infections. Treatment periods up to one year have been effective and well tolerated. The suppression of viral replication may not be sustained after cessation of lamivudine therapy, and very few patients have complete elimination of HBV during therapy. Therefore, long treatment periods may be necessary. Efficacy and tolerability of treatment beyond one year need to be investigated. Resistance to lamivudine has been reported in patients receiving therapy. A combination anti-HBV regimen using lamivudine and other agents with different mechanisms of action should be investigated to maximize the elimination of the viral infection while minimizing or preventing damage to the liver cells and tissues and the development of viral resistance.

Hepatitis B virus transgenic mouse model of chronic liver disease

A model for hepatitis B virus-associated chronic liver disease has been made using cloned hepatitis B virus DNA as a transgene in a severe combined immunodeficient host. These mice consistently support virus gene expression and replication. After adoptive transfer of unprimed, syngeneic splenocytes, these mice cleared virus from liver and serum, and developed chronic liver disease. This model will permit identification of the host and virus contributions to chronic liver disease in the absence of tolerance.

Ribavirin inhibits protein synthesis and cell proliferation induced by mitogenic factors in primary human and rat hepatocytes

Ribavirin, a guanosine analog, used in combination with interferon alpha (IFN-alpha) in the treatment of chronic hepatitis induced by hepatitis C virus (HCV) infection, has been shown to improve liver histology and to decrease transaminases even when administered alone. We analyzed the direct effects of ribavirin on the liver by using primary cultures of human and rat hepatocytes. Between 10 to 60 micromol/L, ribavirin was found to inhibit both the synthesis and secretion of whole proteins in a time- and dose-dependent fashion. Such an effect was confirmed by the measurement of albumin and haptoglobin secretion rates. [3H]-Thymidine incorporation was suppressed both in hepatocyte growth factor-stimulated human hepatocytes and in epidermal growth factor (EGF)-stimulated rat hepatocytes in the presence of ribavirin. The inhibitory effect on DNA synthesis was associated with a delayed progression to S phase of the cell cycle, as determined by flow cytometry and detection of cyclin A and cdc2 which are two proteins expressed during the S phase. The inhibition of DNA synthesis, caused by 50 micromol/L ribavirin, was completely restored by the addition of 80 micromol/L guanosine. These observations demonstrate that ribavirin at concentrations close to those found in plasma of treated patients can directly affect hepatic functions in vitro. Its effects could, however, be reduced in vivo by guanosine salvage supply.

Prevention of severe hepatic injury by interferon-alpha in chronic active hepatitis lacking HBeAg (mutant strain) in a patient with malignant lymphoma

Multidrug chemotherapy with concomitant interferon (IFN)-alpha was performed in a patient with chronic hepatitis lacking the hepatitis Be antigen and malignant lymphoma (ML). Levels of trans-aminases and DNA polymerase (DNA-P) values increased after the fifth course of chemotherapy. Therapy with IFN-alpha for 9 weeks induced a remission in liver disease and complete remission of ML was obtained with subsequent chemotherapy. It was possible to prevent severe liver damage by administering IFN immediately after the elevation of DNA-P. Early introduction of IFN may be effective in the prevention of fulminant hepatic failure from hepatitis from a precore mutant after chemotherapy.