What once was lost, now is found: restoration of hepatitis B-specific immunity after treatment of chronic hepatitis B

Lentiviral vector encoding ubiquitinated hepatitis B core antigen induces potent cellular immune responses and therapeutic immunity in HBV transgenic mice

Predominant T helper cell type 1 (Th1) immune responses accompanied by boosted HBV-specific cytotoxic T lymphocyte (CTL) activity are essential for the clearance of hepatitis B virus (HBV) in chronic hepatitis B (CHB) patients. Ubiquitin (Ub) serves as a signal for the target protein to be recognized and degraded through the ubiquitin-proteasome system (UPS). Ubiquitinated hepatitis B core antigen (Ub-HBcAg) has been proved to be efficiently degraded into the peptides, which can be presented by major histocompatibility complex (MHC) class I resulting in stimulating cell-mediated responses. In the present study, lentiviral vectors encoding Ub-HBcAg (LV-Ub-HBcAg) were designed and constructed as a therapeutic vaccine for immunotherapy. HBcAg-specific cellular immune responses and anti-viral effects induced by LV-Ub-HBcAg were evaluated in HBV transgenic mice. We demonstrated that immunization with LV-Ub-HBcAg promoted the secretion of cytokines interleukin-2 (IL-2), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), generated remarkably high percentages of IFN-γ-secreting CD8(+) T cells and CD4(+) T cells, and enhanced HBcAg-specific CTL activity in HBV transgenic mice. More importantly, vaccination with LV-Ub-HBcAg could efficiently decreased the levels of serum hepatitis B surface antigen (HBsAg), HBV DNA and the expression of HBsAg and HBcAg in liver tissues of HBV transgenic mice. In addition, LV-Ub-HBcAg could upregulate the expression of T cell-specific T-box transcription factor (T-bet) and downregulate the expression of GATA-binding protein 3 (GATA-3) in spleen T lymphocytes. The therapeutic vaccine LV-Ub-HBcAg could break immune tolerance, and induce potent HBcAg specific cellular immune responses and therapeutic effects in HBV transgenic mice.

Designing immune therapy for chronic hepatitis B

Presently-available antiviral drugs may not be a satisfactory option for treatment of patients with chronic hepatitis B (CHB). In spite of presence of several antiviral drugs, sustained off-treatment clinical responses are not common in CHB patients treated with antiviral drugs. In addition, antiviral drug treatment may have limited effects on blocking the progression of HBV-related complications. However, substantial long-term risk of viral resistance and drug toxicity are related with maintenance antiviral therapy in CHB patients with presently-available antiviral agents. The infinite treatments with antiviral drugs for CHB patients are also costly and may be unbearable by most patients of developing and resource-constrained countries. In this situation, there is pressing need to develop new and innovative therapeutic approaches for patients with chronic hepatitis B virus (HBV) infection. Immune therapy has emerged as an alternate therapeutic approach for CHB patients because studies have shown that host immunity is either impaired or derailed or distorted or diminished in CHB patients compared to patients with acute resolved hepatitis B who contain the HBV replication and control liver damages. Both non antigen-specific immune modulators and HBV antigen-specific agents have been used in CHB patients during last three decades. However, similar to antiviral therapy, the ongoing regimens of immune therapeutic approaches have also been unable to show real promises for treating CHB patients. The concept of immune therapy for treating CHB patients seems to be rationale and scientific, however, concerns remain about suitable designs of immune therapy for CHB patients.

HBsAg, HBcAg, and combined HBsAg/HBcAg-based therapeutic vaccines in treating chronic hepatitis B virus infection

BACKGROUND

As the host immunity is diminished in patients with chronic hepatitis B (CHB), different approaches have been used to up-regulate their immune responses to produce therapeutic effects. But, cytokines, growth factors and polyclonal immune modulators could not exhibit sufficient therapeutic effects in these patients. Immune therapy with HBV-related antigens (vaccine therapy) has been used in CHB patients. But there is a paucity of information about the design of HBV antigen-based immune therapy in these patients.

DATA SOURCE

Preclinical and clinical studies on immune therapy with HBsAg-based vaccine, HBcAg and combination of HBsAg/HBcAg-based vaccines have been discussed.

RESULTS

HBsAg-based prophylactic vaccine was used as an immune therapeutic agent in CHB patients; however, monotherapy with HBsAg-based immune therapy could not lead to sustained control of HBV replication and/or liver damages. HBsAg-based vaccine was used as a combination therapy with cytokines, growth factors, and antiviral drugs. HBsAg-based vaccine was also used for cell-based therapy. However, satisfactory therapeutic effects of HBsAg-based vaccine could not be documented in CHB patients. In the mean time, evidences have supported that HBcAg-specific immunity is endowed with antiviral and liver protecting capacities in CHB patients. Recent data concentrate on the clinical use of combined HBsAg- and HBcAg-based vaccines in CHB patients.

CONCLUSION

Antigen-based immune therapy with HBV-related antigens may be an alternative method for the treatment of CHB patients but proper designs of antigens, types of adjuvants, dose of vaccinations, and routes of administration need further analyses for the development of an effective regimen of immune therapy against HBV.

Non-antigen-specific and antigen-specific immune therapies for chronic hepatitis B: evidences from laboratory benches and patient's bedsides

INTRODUCTION

Due to unsatisfactory therapeutic efficacy and considerable side effects of antiviral drugs in patients with chronic hepatitis B (CHB), immunotherapy has emerged as an alternative approach. CHB immunotherapy may be categorized into two main types: i) non-antigen-specific immune therapy and ii) hepatitis B virus (HBV) antigen-specific immune therapy. Although different immune modulators have been used in CHB patients for the last two to three decades, the nature and design of ongoing regimens of immunotherapeutic approaches need considerable modifications.

AREAS COVERED

In this review, the authors have outlined the relevant immunotherapies for CHB patients that have been used for the last two to three decades. The mechanisms underlying the limited therapeutic efficacy of available therapeutic agents for CHB patients have been discussed to aid in the development of an effective therapeutic approach for these patients.

EXPERT OPINION

Circumstantial evidence indicates that a better regimen of immunotherapy may be developed using different HBV-related antigens or combinations of two or more HBV-related antigens, or combinations of HBV-related antigens and antiviral drugs. However, the capacity of 'inducible immunity' by immune modulators to cure or block progression of liver diseases in CHB patients needs to be addressed.

Effect of lowering HBV DNA levels by initial antiviral therapy before adding immunomodulator on treatment of chronic hepatitis B

BACKGROUND

Lower hepatitis B virus DNA (HBV DNA) levels are associated with better responses in chronic hepatitis B (CHB). It is unclear whether an initial phase of antiviral treatment to lower HBV DNA levels before adding immunomodulator therapy is more effective than the strategy of using immunomodulators from the beginning.

AIM

The aim of the study was to compare the efficacy of lamivudine followed by pegylated-interferon (peg-IFN) therapy with placebo followed by peg-IFN therapy in HBeAg-positive CHB patients.

PATIENTS AND METHODS

Sixty-three treatment-naive HBeAg-positive patients with histologically proven CHB and alanine aminotransferase (ALT) > 1.2 x upper limit of normal (ULN) received placebo for 4 wk followed by peg-IFN 1.0 mug/kg/wk for next 24 wk (group A, N = 27; age 32 +/- 11 yr; M:F = 25:2) or lamivudine 100 mg per day for 4 wk followed by peg-IFN 1.0 mug/kg/wk for next 24 wk (group B, N = 36; age 32.5 +/- 10.5 yr; M:F = 31:5). Patients were followed for next 24 wk after completion of treatment. Biochemical and virologic responses were assessed at weeks 4, 28, and 52 and analysis was done on intention-to-treat basis.

RESULTS

At wk 4, mean +/- SD of log change in DNA from baseline was 0.2594 +/- 1.7873 in group A and 1.2186 +/- 1.6347 in group B, respectively (P = 0.032). At week 28, undetectable HBV DNA was seen in eight (29.6%) and 16 (44.4%) patients in groups A and B, respectively (P= 0.298). At week 28, HBeAg loss occurred in eight (29.6%) in group A and 15 (41.7%) in group B (P = 0.43). Six months posttherapy, at week 52, undetectable HBV DNA was seen in four (14.8%) and 18 (50%) in groups A and B, respectively (P = 0.028) and HBeAg loss was maintained in four (14.8%) and 14 (38.9%) (P = 0.05) patients. Normal ALT was seen in five (18.5%) and 10 (27.8%) at week 28 (P = 0.552) and five (18.5%) and 13 (36.1%) at week 52 (P = 0.159) in groups A and B, respectively. There was a significant correlation among achievement of HBeAg loss, anti-HBe appearance, and undetectable HBV DNA levels at week 28 (P = 0.008) and 52 (P < 0.001) and HBV DNA levels at week 4.

CONCLUSIONS

The strategy of using an antiviral initially to decrease HBV DNA levels before adding an immunomodulatory agent leads to improved sustained virological response as compared with using immunomodulator from the start.

Clinical status and hepatic pathology of patients with chronic hepatitis B virus infection in immune tolerant phase

AIM: To investigate the characteristics of the clinical status and hepatic pathology of patients with hepatitis B virus (HBV) infection in immune tolerant phase.

METHODS: Three hundred and eighty patients with chronic HBV infection of different phases were involved in this study. The data about the ages of patients, vertival transmission, family history of HBV infection, hepatocytic expression of HBsAg and HBCAg and hepatic pathology were statistically analyzed.

RESULTS: It was found that 61.8% of patients in immune tolerant stage were less than 16 years old, and 46.6% with a family history of HBV infection. Vertival transmission covered a percentage of 55% and in patients of immune tolerant stage. Of 89 patients in immune tolerant stage, the ratio of HBcAg expression was 78.7%. The ratios above were significantly higher than the corresponding ones in patients of immune active stage or non-active status (χ² = 38.73, 49.08, 17.2, 31.69, respectively, all P < 0.01). For the patients less than 16 years old, the ratios of hepatocytic expression of HBSAg and HBCAg were 64.3% (45/75) and 72.9% (51/79), respectively, in immune tolerant stage which were obviously higher than those in immune active stage or non-active status (χ² = 17.51, 31.17, both P < 0.001). For the patients more than 16 years old, the ratios of hepatocytic HBSAg and HBCAg expression were 35.7% (25/75) and 27.1% (19/70), respectively, in immune tolerant stage, which were markedly lower than those in immune active stage or non-active status (χ² = 17.51, χ² = 31.17, both P < 0.001).

CONCLUSION: Vertival transmission and family history of HBV infection have higher proportions in chronic HBV infection patients less than 16 years old in immune tolerant stage. HBV replicates most in patients of immune tolerant stage, especially in those less than 16 years old.

Long-term follow-up of hepatitis B carrier children treated with interferon and prednisolone

The long-term outcome of treatment with Interferon Alpha 2B with and without Prednisolone priming in children infected perinatally with hepatitis B was reviewed. The group studied included 48 children (aged 2-16 years), who were HBe antigen and hepatitis B DNA positive between 1991 and 1993. Twenty children were randomized to a therapeutic trial at that time, and received Prednisolone in reducing doses for 6 weeks and Interferon for 16 weeks while 22 children were monitored without treatment for 12 months. Fourteen of the untreated group and 6 additional children later received treatment with Interferon alone (n = 20). Eight children for whom treatment was declined were followed long term. Median follow-up was 7.5 years (range 1.5-10.6). There was no significant effect of Interferon therapy on seroconversion with or without Prednisolone at 12 months post-treatment compared to untreated children. On longer term follow-up, the 5-year HBeAg to anti-HBe seroconversion percentages, estimated from Kaplan-Meier curves, were 54% for Prednisolone plus Interferon, 22% for Interferon alone, and 12% for untreated children. The median time to seroconversion was 3.9 years (range 0.4-8.2) and was shortest in those treated with Prednisolone plus Interferon. Children who had elevated hepatic transaminase enzymes prior to treatment or during Prednisolone priming had a better response. In contrast to many European studies, no child cleared HBsAg and produced anti-HBs. Treatment with Prednisolone priming and Interferon, improved both the time and rate of seroconversion compared to no treatment or Interferon alone, suggesting that this combination of drugs might have an immunomodulatory effect.

Sequential combination therapy of HBe antigen-negative/virus-DNA-positive chronic hepatitis B with famciclovir or lamivudine and interferon-alpha-2a

BACKGROUND/AIMS

Hepatitis B e antigen-negative/hepatitis B virus (HBV) DNA-positive chronic hepatitis B (CHBe-) exhibits a high relapse rate on monotherapy with lamivudine or interferon-alpha (IFN-alpha). We investigated, whether sequential therapy with famciclovir or lamivudine followed by combination with IFN-alpha-2a improves durable virologic response in CHBe- characterized by mutation analysis of the HBV precore genome region.

METHODS

Fourteen patients were treated with famciclovir (n=3) or lamivudine for 4 weeks to reduce the viral load, and subsequently with the combination of the nucleoside analogue and IFN-alpha-2a until 16 weeks beyond the loss of serum HBV-DNA.

RESULTS

Median duration of therapy was 29.0 weeks (range 20.6-48.3 weeks). Serum HBV-DNA was undetectable and alanine aminotransferase had normalized in all patients at the end of treatment. Seven (50%) patients maintained a sustained response 12 months after end of treatment. Only two of them had been infected by HBV with the G1896A mutation. Most patients (5/7) with the G1896A mutation relapsed within 4 months after therapy.

CONCLUSION

Sequential combination therapy can induce sustained virologic response in a subgroup of CHBe-, but most with the G1896A precore mutant HBV relapse. Trials of CHBe- should be based on characterization of HBV mutants.

Effects of zhaoyangwan on chronic hepatitis B and posthepatic cirrhosis

AIM: To study the therapeutic effects of zhaoyangwan (ZYW) on chronic hepatitis B and hepatic cirrhosis and the anti-virus, anti-fibrosis and immunoregulatory mechanisms of ZYW.

METHODS: Fifty cases of chronic hepatitis B and posthepatic cirrhosis with positive serum HBsAg, HBeAg, anti-Hbc and HBV-DNA were divided randomly and single-blindly into the treatment group (treated with ZYW) and the control group (treated with interferon). After 3 month treatment, the effects of the treatment group and the control group were evaluated.

RESULTS: The serum ALT normalization was 83.3%(30/36) in the treatment group and 85.7%(12/14) in the control group, with no significant difference (χ² = 0.043, P > 0.05). After the course, the negative expression rates of the serum HBV-DNA and HBeAg were 44.4%(16/36) and 50%(18/36) in the treatment group, and 50%(7/14) and 50%(7/14) in the control group, respectively, with no significant difference (χ² = 0.125, χ² = 0.00, both P > 0.05). Negative HBsAg and positive HBsAb appeared in 4 cases of the treatment group and 1 case of the control group. Serum anti-HBc turned negative in 6 cases of the treatment group and 1 case of the control group, respectively. After the ZYW treatment, serum CD₃⁺, CD₄⁺, CD₈⁺, CD₄⁺/CD₈⁺ and NK cell activation were significantly increased. Only serum CD₃⁺ and NK cell activation were significantly increased in the control group with a significant difference between the two groups. The serum C₄, C_1q, C₃, B and C₉ were significantly increased in the treatment group. In the control group only the serum C₄ was increased. The concentration of serum interferon had no change after treatment with ZYW, while it was significantly increased in the control group after treatment with interferon. The ultrastructure of the liver restored, which helped effectively to reduce the degeneration and necrosis of hepatic cells, infiltration of inflammatory cells and hepatic cirrhosis.

CONCLUSION: ZYW is a pure Chinese herbal medicine. It can exert potent therapeutic effects on chronic hepatitis B and posthepatic cirrhosis. ZYW has similar therapeutic effects to those of interferon. It is cheap and easily administered with no obvious side-effects. It can be widely used in clinical practice.

Plasma pituitary adenylate cyclase activating polypeptide (PACAP) levels in chronic hepatitis B patients under lamivudine treatment

OBJECTIVE

Lamivudine is a nucleoside analogue with potent antiviral activity against hepatitis B virus (HBV). Plasma pituitary adenylate cyclase activating polypeptide (PACAP) is a multifunctional neuropeptide that is produced within the lymphoid microenvironment and induces the production of Th2-type cytokines. The aim of our study was to investigate the possible alterations of plasma PACAP-38 levels in chronic hepatitis B (CHB) patients during lamivudine treatment and to compare them with biochemical, virological and histological data.

METHODS

Plasma PACAP-38 levels were measured using competitive radio-immune analysis (RIA) in 25 CHB patients before and after completion of a 52-week lamivudine treatment period and in 22 healthy blood donors. Biochemical evaluation was done at baseline and every three months during treatment. Virological evaluation (HBV-DNA) was performed at baseline and at weeks 24 and 52 of treatment. Baseline liver histology was assessed for all patients at the beginning and at week 52 of the study for histological comparison with the pretreatment biopsy, according to the Ishak scoring system. Statistical evaluation of data was done using analysis of variance and Student's t-test.

RESULTS

Virological breakthrough was observed in seven (28%) patients at week 52 of treatment. Histological improvement was observed in 21 (84%) CHB patients, despite the emergence of tyrosine-methionine-aspartate-aspartate (YMDD) mutations. Plasma PACAP-38 levels were significantly lower in CHB patients at baseline than in healthy blood donors. Significant elevation of plasma peptide levels was observed in CHB patients after the completion of lamivudine treatment period, even in the subgroup of those who exhibited YMDD variants.

CONCLUSION

The elevation of plasma PACAP-38 levels in treated CHB patients following lamivudine-induced elimination of viraemia suggests a possible alteration of T-cellular immune response, resulting in biochemical and histological remission of liver disease, even in patients who exhibited virological breakthrough.

Prednisolone priming enhances Th1 response and efficacy of subsequent lamivudine therapy in patients with chronic hepatitis B

Asian lamivudine trial has shown that hepatitis B e antigen (HBeAg) seroconversion rate during 1 year of lamivudine therapy was only 16% but was 64% in the subgroup of patients with a pretherapy serum alanine transaminase (ALT) level over 5 times the upper limit of normal (ULN). To test whether ALT rebound following corticosteroid priming enhances response to lamivudine therapy, a pilot study was conducted in 30 patients with ALT levels less than 5x ULN (43-169; N < 36 U/L). They received 30 mg of prednisolone daily for 3 weeks, 15 mg daily for 1 week, no treatment for 2 weeks, and then 150 mg of lamivudine daily for 9 months. Complete response (CR) was defined as ALT normalization with HBV-DNA seroclearance and HBeAg seroconversion. Peripheral blood mononuclear cell proliferation and cytokine secretion in response to recombinant HBV core antigen were serially assayed in 7 patients during priming and after withdrawal of prednisolone. Clinical rebound with an ALT over 5x ULN was observed in 20 patients (67%). Of these 20, 12 (60%) showed CR as compared with 1 (10%) of the 10 patients without significant ALT rebound (P <.002). The HBeAg seroconversion sustained in 70% of the patients 3 to 6 months after the end of lamivudine therapy. Immunological assays revealed that the responders showed Th1 dominant response and higher stimulation index to prednisolone priming. No serious side effect was encountered. These results suggest that corticosteroid priming induced immune/ALT rebound greatly enhances response to lamivudine therapy in chronic hepatitis B. Confirmation by randomized controlled trial is needed.

Lamivudine. A review of its therapeutic potential in chronic hepatitis B

Lamivudine is a deoxycytidine analogue that is active against hepatitis B virus (HBV). In patients with chronic hepatitis B, lamivudine profoundly suppresses HBV replication. Clinically significant improvements in liver histology and biochemical parameters were obtained with lamivudine in double-blind, randomised, trials in hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B and compensated liver disease. After 52 weeks of treatment, relative to placebo (< or = 25%), significantly more Chinese (56%) or Western patients (52%) treated with lamivudine 100 mg/day had reductions of > or = 2 or more points in Knodell necro-inflammatory scores. Moreover, significantly fewer lamivudine 100 mg/day than placebo recipients had progressive fibrosis in liver biopsies (< or = 5 vs > or = 15%) and fewer lamivudine- than placebo-treated patients progressed to cirrhosis (1.8 vs 7.1%). More lamivudine 100 mg/day than placebo recipients acquired antibodies to HBeAg after 52 weeks (16 vs 4% in Chinese patients and 17 vs 6% in Western patients). ALT levels normalised in significantly more lamivudine than placebo recipients enrolled in these trials. In HBeAg-negative, HBV DNA positive patients with compensated liver disease enrolled in a double-blind, randomised study, HBV DNA levels were suppressed to below the limit of detection (< 2.5 pg/ml) and ALT levels normalised in 63% and 6% of patients treated with lamivudine 100 mg/day or placebo for 24 weeks. Clinically significant improvements in liver histology were obtained in 60% of patients treated with lamivudine for 52 weeks in this study. Lamivudine 100 mg/day for 52 weeks produced similar or significantly greater improvements in liver histology and ALT levels than 24 weeks' treatment with lamivudine plus interferon-alpha. In liver transplant candidates with chronic hepatitis B and end-stage liver disease, lamivudine 100 mg/day alone, or in combination with hepatitis B immune globulin, generally suppressed HBV replication and appeared to protect the grafted liver from reinfection. Lamivudine 100 mg/day suppressed viral replication and improved liver histology in liver transplant recipients with recurrent or de novo chronic hepatitis B. Lamivudine 300 or 600 mg/day reduced HBV replication in HIV-positive patients. The incidence of adverse events in patients with chronic hepatitis B and compensated liver disease treated with lamivudine 100 mg/day or placebo for 52 to 68 weeks was similar. 3.1- to 10-fold increases in ALT over baseline occurred in 13% of patients during treatment with lamivudine 100 mg/day or placebo for 52 weeks. Post-treatment ALT elevations were more common in lamivudine than placebo recipients; however, these generally resolved spontaneously; < or = 1.5% of lamivudine- or placebo-treated patients experienced hepatic decompensation.

CONCLUSION

Lamivudine inhibits HBV replication, reduces hepatic necro-inflammatory activity and the progression of fibrosis in patients with chronic hepatitis B, ongoing viral replication and compensated liver disease including HBeAg-negative patients. The drug also suppresses viral replication in liver transplant recipients and HIV-positive patients. Thus, lamivudine is potentially useful in a wide range of patients with chronic hepatitis B and ongoing viral replication.