Pilot study of recombinant human interleukin 2 for chronic type B hepatitis

Low-dose Interleukin-2 Therapy: Fine-tuning Treg in Solid Organ Transplantation?

Regulatory T cells (Treg), a subset of CD4 + T cells, are potent regulators of immune reactions, which have been shown to be a promising therapeutic alternative to toxic immunosuppressive drugs. Data support the utility of Treg in managing immunopathologies, including solid organ transplant rejection, graft-versus-host disease, and autoimmune disorders. Notably, reports suggest that interleukin-2 (IL-2) is critical to survival of Treg, which constitutively express high levels of CD25, that is, the IL-2 receptor α-chain, and are exquisitely sensitive to IL-2, even at very low concentrations in contrast to effector T cells, which only upregulate IL-2 receptor α-chain on activation. This has led to the notion of using low doses of exogenous IL-2 therapeutically to modulate the immune system, specifically Treg numbers and function. Here, we summarize developments of clinical experience with low-dose IL-2 (LD-IL-2) as a therapeutic agent. So far, no clinical data are available to support the therapeutic use of LD-IL-2 therapy in the solid organ transplant setting. For the latter, fine-tuning by biotechnological approaches may be needed because of the narrow therapeutic window and off-target effects of LD-IL-2 therapy and so to realize the therapeutic potential of this molecule.

Restoration of HBV-specific CD8+ T-cell responses by sequential low-dose IL-2 treatment in non-responder patients after IFN-α therapy

Patients with chronic hepatitis B (CHB) undergoing interferon (IFN)-α-based therapies often exhibit a poor HBeAg serological response. Thus, there is an unmet need for new therapies aimed at CHB. This study comprised two clinical trials, including 130 CHB patients, who were treatment-naïve; in the first, 92 patients were systematically analyzed ex vivo for interleukin-2 receptor (IL-2R) expression and inhibitory molecules expression after receiving Peg-IFN-α-2b therapy. In our second clinical trial, 38 non-responder patients, in whom IFN-α therapy had failed, were treated with or without low-dose IL-2 for 24 weeks. We then examined the hepatitis B virus (HBV)-specific CD8+ T-cell response and the clinical outcome, in these patients. Although the majority of the participants undergoing Peg-IFN-α-2b therapy were non-responders, we observed a decrease in CD25 expression on their CD4+ T cells, suggesting that IFN-α therapy may provide a rationale for sequential IL-2 treatment without increasing regulatory T cells (Tregs). Following sequential therapy with IL-2, we demonstrated that the non-responders experienced a decrease in the numbers of Tregs and programmed cell death protein 1 (PD-1) expression. In addition, sequential IL-2 administration rescued effective immune function, involving signal transducer and activator of transcription 1 (STAT1) activation. Importantly, IL-2 therapy significantly increased the frequency and function of HBV-specific CD8+ T cells, which translated into improved clinical outcomes, including HBeAg seroconversion, among the non-responder CHB patients. Our findings suggest that sequential IL-2 therapy shows efficacy in rescuing immune function in non-responder patients with refractory CHB.

Sequential combination therapy with interferon, interleukin-2 and therapeutic vaccine in entecavir-suppressed chronic hepatitis B patients: the Endeavor study

BACKGROUND

Switching from nucleos(t)ide analogues to interferon (IFN) improves hepatitis B surface antigen (HBsAg) loss. We aimed to evaluate whether combining immunomodulators such as interleukin-2 (IL-2) and therapeutic vaccine with IFN enhances HBsAg loss in entecavir (ETV)-suppressed patients.

METHODS

Ninety-four patients exhibiting virological suppression and hepatitis B e antigen (HBeAg) loss following ETV treatment were randomized 1:1:1 to receive ETV (group I) or IFN (group II) for 48 weeks, or IFN and vaccine for 48 weeks plus IL-2 for 12 weeks (group III). The primary endpoint was HBsAg loss at week 48. Peripheral natural killer (NK) cells and regulatory T cells (Treg) were measured as immune checkpoint indicators.

RESULTS

Mean HBsAg decline at week 48 was significantly greater in group III (0.85 log 10 IU/mL) and group II (0.74 log 10 IU/mL), than in group I (0.13 log 10 IU/mL). At week 48, 9.38%, 3.03%, and 3.70% of subjects in group III, II, and I, respectively, achieved HBsAg loss. Among patients with baseline HBsAg titers ranging from 100 to 1500 IU/mL, HBsAg loss rate was 27.3, 7.1, and 0% in group III, II, and I, respectively. Responders in group III showed a significantly higher increase in CD56^bright CD16^-NK cells from week 24 to 36, and a significant decline in Treg from week 12 to 24 than non-responders.

CONCLUSION

For ETV-suppressed patients, particularly those with low baseline HBsAg levels, combination therapy with IFN and other immunomodulators may enhance HBsAg loss, while successful response correlates with partial restoration of NK cells and Tregs.

Interleukin-2 Plus Ribavirin Versus Interferon-??-2b Plus Ribavirin in Patients with Chronic Hepatitis C Who Did Not Respond to Previous Interferon-??-2b Treatment

BACKGROUND

Interferon (IFN)-alpha-2b therapy has been shown to improve clinical conditions of patients with chronic hepatitis C. Several studies showed that the addition of ribavirin to IFNalpha-2b greatly improved the biochemical as well as the virologic and histological response rate in patients with chronic hepatitis C. The aim of this study was to evaluate biochemical, virologic, and histological responses as well as adherence to a treatment employing ribavirin plus low doses of recombinant interleukin (IL-2) or IFNalpha-2b in subjects with chronic active hepatitis C, which relapsed or did not respond to previous treatment with interferon alone.

PATIENTS AND METHODS

We evaluated all 75 consecutive adult patients with chronic hepatitis C admitted to our department, who were previously treated with one course of recombinant or lymphoblastoid IFNalpha-2b (3 million to 6 million IU three times a week for at least 4 months), and either relapsed or did not respond to this treatment. Sixty patients met the inclusion criteria for enrollment in our study. Randomization was performed on the basis of a computer-generated list. The treatment schedule was based on subcutaneous administration of recombinant IFNalpha-2b (Intron A) at a dosage of 3 million IU every day, or IL-2 (aldesleukin) at a dose of 1 million IU every day, with oral ribavirin administered 400 mg twice daily (morning and night) [for patients weighing <75 kg] or 500 mg twice daily (for those weighing > or = 75 kg). The planned treatment period was 6 months.

RESULTS

Both IFN and IL-2 treatment groups achieved a significant biochemical response with respect to baseline values at the end of the treatment (p < 0.0001 for both) and at the end of the follow up (p < 0.001 for both). The differences between the two groups at the end of treatment and at the end of the follow up were significant (p < 0.04 and p < 0.003 respectively) in favor of IL-2-treatment. The virologic response rate for IL-2-treated patients was significantly higher than for IFN-treated patients at months 3 (p < 0.05) and 6 (p < 0.05) of the treatment. Both groups showed significant improvement in histological activity index with respect to baseline values, but the difference between the groups was not significant. No withdrawals have been registered.

CONCLUSION

The combination of IL-2 and ribavirin seems to increase the probability of a sustained biochemical and virologic response in patients with chronic hepatitis C that is unresponsive to IFN. Our study showed that IL-2 plus ribavirin may provide a clinically important option that appears to be well tolerated and effective in patients with chronic hepatitis C virus infection.

Mucosal cytokine therapy: marked antiviral and antitumor activity

Mucosal administration of the Th1 stimulatory cytokines interleukin-2 (IL-2), IL-12, IL-15, IL-18, or granulocyte-macrophage colony-stimulating factor (GM-CSF) induced antiviral activity in mice challenged systemically with a lethal dose of encephalomyocarditis virus (EMCV) similar to that observed following parenteral administration. In contrast, mucosal administration of the Th2 stimulatory cytokines IL-4, IL-5, IL-10, or IL-13 did not affect significantly the survival of EMCV-infected animals. Mucosal administration of IL-2 or IL-12 also exerted a marked antitumor activity in mice inoculated intravenously with Friend erythroleukemia cells. Recombinant IL-2 and IL-18, but none of the other recombinant cytokines tested, induced low levels of IFN in vitro. Polyclonal antibodies to both mouse and human interferon-alpha/beta (IFN-alpha/beta) abrogated the antiviral activity of IL-2 in vivo, even though the anti-human IFN-alpha/beta antibody did not neutralize mouse IFN-alpha/beta, and neither antibody bound to IL-2. IL-15 did not exhibit antiviral activity in IFN-alpha/beta R-/- mice, which are deficient in natural killer (NK) cell activity. These results suggest that mucosal Th1 cytokine therapy induces a soluble factor or activates a specific cell population in the lymphoid or epithelial tissue of the oropharyngeal cavity, which potentiates elimination of virus-infected or neoplasic cells systemically.

Double-blind, randomized controlled trial of interleukin-2 treatment of chronic hepatitis B

Pilot studies have demonstrated that recombinant interleukin 2 (rIL-2) has an indirect antiviral activity against hepatitis B virus, but the minimal dose of rIL-2 for induction of this effect was not defined. The aim of the study was to ascertain the most efficient dose of rIL-2 for induction of the loss of detectable serum HBV-DNA or a 50% or greater decrease in its level. Thirty-one patients with chronic hepatitis B, hepatitis B e antigen and serum HBV-DNA positive were enrolled in this double-blind randomized controlled trial. Patients were divided: Group I (n = 8) placebo; Group II (n = 7) treated with 0.9 MU of rIL-2 subcutaneously administered daily for 8 weeks; Group III (n = 8) treated with 1.8 MU of rIL-2 under the same schedule; Group IV (n = 8) which received 3.6 MU of rIL-2 under the same conditions. At the end of treatment 25% of the patients in the placebo group, and 13% and 25% in rIL-2 groups III and IV, respectively, had a decrease in HBV-DNA higher than 50% of the basal value. None of the patients lost serum HBV-DNA. Only three patients (one from group II and two from group IV) normalized the ALT levels. Overall, during treatment, ALT levels decreased in the treated groups. This decrease occurred simultaneously with an increase in serum HBV-DNA concentration. Since the response rate in the treated groups was similar to that of the placebo group, rIL-2 is not useful as monotherapy for the treatment of chronic hepatitis B at the doses and schedules used in this study.

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.

Interferon-alpha-2a. A review of its pharmacological properties and therapeutic use in the management of viral hepatitis

Interferon-alpha-2a is a recombinant interferon with antiviral, antitumour and immunomodulatory properties. Clinical studies have demonstrated that the drug offers therapeutic benefit in patients with some forms of chronic viral hepatitis. Remission, as measured by clearance of viral DNA and hepatitis B 'e' antigen (HBeAg), and normalisation of serum alanine aminotransferase levels, is observed in approximately 30 to 45% of patients with chronic hepatitis B receiving interferon-alpha-2a (2.5 to 18MU administered 3 times/week); about 5 to 15% of untreated controls remit spontaneously every year. Complete recovery [with loss of hepatitis B surface antigen (HBsAg)] is usually noted in < 20% of treated individuals. Similar response rates have been reported in the relatively small number of children evaluated to date. Although numerous studies have shown that interferon-alpha-2a (at various dosages) induces biochemical amelioration of chronic hepatitis C in approximately 50 to 75% of patients, relapse is common. Thus, long term remission may only be observed in about 15 to 30% of treated patients. On the other hand, this disorder remits spontaneously in only a few patients. The role of interferon-alpha-2a in the treatment of chronic hepatitis D remains unclear. Although preliminary data suggest it may be beneficial, cessation of therapy is generally followed by relapse. As with other types of interferons, most patients receiving interferon-alpha-2a experience an 'influenza-like' syndrome, which tends to diminish with continuing therapy. Other effects such as fatigue, lethargy, anorexia and weight loss are usually dose-limiting. Serum neutralising antibodies develop in approximately 10 to 20% of treated patients. Thus, although response rates are less than optimal, interferon-alpha-2a is a drug of first choice amongst the limited therapeutic options available for the management of well-compensated chronic viral hepatitis B or C.

A randomized controlled trial of thymopentin therapy in patients with chronic hepatitis B

Strategies of treatment of chronic hepatitis type B are currently based on the use of either antiviral or immunomodulatory agents. A randomized, controlled trial was performed to assess the safety and efficacy of 6-month thymopentin therapy in 30 patients with chronic hepatitis B. Inclusion criteria were biopsy-proven chronic hepatitis, elevated alanine aminotransferase and serum HBsAg and HBV-DNA positivity for at least 12 months. At the conclusion of the study (1 year), HBV-DNA was negative and alanine aminotransferase had normalized in 13% and 20% of treated cases and in 20% and 27% of controls. None of the ten treated and one of the nine control patients who were initially HBeAg positive subsequently cleared HBeAg. None became HBsAg negative. A histologic improvement was noted in 27% of the treated patients compared with 18% of controls. These results indicate that this regimen of thymopentin therapy is not effective in treating chronic hepatitis B.

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.

Pilot study of natural human interleukin-2 in patients with chronic hepatitis B. Immunomodulatory and antiviral effects

Ten patients with chronic hepatitis B received increasing doses of nIL-2 (30,000 U, 100,000 U, 300,000 U, 1.0 million U) subcutaneously in a phase I trial. Each dose was applied once per week over 3 weeks. Serum samples were taken before and 2, 12, 24, 48 and 72 h after the first application of each dose level. Serum concentrations of interleukin-1 (IL-1), IL-2, IL-6, interferon-alfa (IFN-alpha), IFN-gamma, tumor necrosis factor-alpha (TNF-alpha) and GM-CSF as well as the cytokine-dependent serum components neopterin, beta-2-microglobulin (B2M), C-reactive protein (CPR), soluble IL-2-receptor (sIL-2R) and 2'-5'-oligoadenylate synthetase (2-5 OA) were assayed using ELISAs and RIAs. None of the samples tested contained measurable cytokine levels other than IL-2. A low and non-toxic dose of 300,000 U nIL-2 was already biologically active with induction of neopterin, B2M and sIL-2R. Dose-dependent changes peaked 24-48 h after application. The same patients were then enrolled in a phase II trial. Treatment in five of the patients was continued twice per week for 3 months with a biologically active dose of 300,000 U nIL-2 subcutaneously. Two of these patients as well as another five patients from the original group were treated with 1.0 million U nIL-2 subcutaneously, twice weekly for 3 months. Neither a biologically active but non-toxic dose of 300,000 U nIL-2, nor a toxic dose of 1.0 million U resulted in permanent clearance of hepatitis B early antigen (HBeAg).(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin 6 production by peripheral blood mononuclear cells in patients with chronic hepatitis B virus infection and primary biliary cirrhosis

IL-6 production by peripheral blood mononuclear cells (PBMC) was studied in patients with chronic hepatitis B virus (HBV) infection and primary biliary cirrhosis (PBC) using the ELISA method. Spontaneous production of IL-6 was significantly increased in patients with HBeAg+ chronic hepatitis (CH). The cultures stimulated with lipopolysaccharide and lectin-free interleukin-2 (IL-2) showed enhanced IL-6 production both in controls and all patient groups compared with culture without any stimulation. IL-6 production in response to IL-2 was higher in patients with HBeAg+ CH and PBC than in controls. In PBMC with increased IL-6 production, monocyte function was increased in patients with HBeAg+ CH and PBC, while B cells from PBC showed elevated response to Staphylococcus aureus Cowan 1. IL-6 production in the presence of HBeAg was greater in anti-HBe+ patients than in HBeAg+ ones. These results suggest that IL-6 response is involved in the immune response in patients with chronic liver disease.

Predictive indicators for the therapeutic effect of OK-432 in patients with chronic active type B hepatitis

Twenty-two patients with chronic type B hepatitis were treated with OK-432. Immunological parameters were serially measured to find predictive indicators for the seroconversion from hepatitis B envelope antigen (HBe Ag) to anti-HBe. In patients who achieved the disappearance of HBe Ag associated with or without the appearance of anti-HBe, the numbers of CD8+DR+ and CD4+DR+T cells in peripheral blood increased gradually during OK-432 therapy and then reduced subsequently to the seroconversion from HBe Ag positive to anti-HBe positive. Increases of DR-positive T cells in numbers were significantly correlated with increased amounts of IFN-gamma produced in response to in vitro OK-432 stimulation. In vitro OK-432-stimulated IFN-gamma production and the increase of CD8+DR+T cells in number in peripheral blood could be proposed as predictive indicators for the disappearance of HBe Ag.

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.

Low serum levels of alpha-interferon, gamma-interferon, and interleukin-2 in alcoholic cirrhosis

The existence of cellular immune deficit in alcoholic cirrhosis, together with the role of alpha- and gamma-interferon and interleukin-2 in the immune system, led us to compare serum levels of these immune system mediators in a group of 40 patients with alcoholic cirrhosis classified according to Child-Pugh's grade of severity of liver disease and 23 healthy volunteers. Serum levels of alpha-IFN, gamma-IFN, and IL-2 were significantly depressed in alcoholic cirrhotics, with no significant differences between the different degrees of hepatic damage. The results suggest a profound alteration in the immune system of alcoholic cirrhotics, which may contribute to the development of the disease and the accompanying immune system deficit.

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.

Effect of sizofiran, a polysaccharide, on interferon gamma, antibody production and lymphocyte proliferation specific for hepatitis B virus antigen in patients with chronic hepatitis B

To examine whether sizofiran (SPG), a polysaccharide isolated from Schizophyllum commune Fries, could modulate the immune response of immunocompetent cells to hepatitis B virus (HBV) nucleocapsid antigens, we investigated in vitro the production of interferon-gamma (IFN-gamma) and antibody (antibody to HB core and e antigens; anti-HBc and anti-HBe), and proliferation by peripheral blood mononuclear cells (PBMC) from six patients with chronic hepatitis B and four control individuals in the presence of recombinant HBcAg and purified HBeAg. Sizofiran alone in culture and in combination with HBV Ag was found to enhance IFN-gamma production and the proliferative response of PBMC from the patients compared with corresponding medium or HBV Ag alone culture. In contrast, antibody production was not elicited by SPG alone, but amplified by the drug in HBcAg-stimulated culture. In vitro leukocyte IFN-alpha addition increased IFN-gamma production, but suppressed the proliferation of PBMC from both controls and patients in the presence or absence of SPG and HBV Ag. These results indicate that SPG is able to modulate both cellular and humoral immune responses specific for nucleocapsid antigens in patients with chronic hepatitis B.

Electron microscopic observations on the accumulation of large granular lymphocytes (pit cells) and Kupffer cells in the liver of rats treated with continuous infusion of interleukin-2

Treatment schedules were investigated for in vivo induction of lymphokine-activated killer cells in the rat liver. Treatment of rats with continuous systemic or regional infusion of recombinant human interleukin-2 with a dose of 4 to 8 x 10(4) U/day during 7 days, resulted in an increase in number of large granular lymphocytes or pit cells in the liver up to 43 times normal. Kupffer cells, nongranular lymphocytes, monocytes and neutrophils also increased in number, but with a maximal fivefold increase this was much less pronounced than for large granular lymphocytes. Kupffer cells showed morphological signs of activation and were frequently seen in mitosis. Frequent mitoses were also observed for large granular lymphocytes, but not for other leukocytes. This indicates that the effect of interleukin-2 treatment on hepatic (sinusoidal) cells was primarily directed to large granular lymphocytes and Kupffer cells. The large granular lymphocyte accumulation occurred mainly intrasinusoidally, but they were also frequently observed in the space of Disse where they are not found in control rats. This may be explained partly by the observed damage or gaps in the endothelial lining. The intrasinusoidal large granular lymphocytes adhered to the endothelium and to Kupffer cells. Higher responses, for all cell types, were found when interleukin-2 was administered regionally, that is, through the hepatic artery rather than through the systemic route (jugular vein), although the differences were not statistically significant. Doses below 4 x 10(4) U/day did not result in significant increases of large granular lymphocytes in the liver.

Viral hepatitis. The new ABC's

Hepatitis may be caused by hepatitis A virus, hepatitis B virus, hepatitis C virus (classic non-A non-B viral hepatitis), hepatitis D virus (delta agent), and hepatitis E virus (epidemic non-A non-B viral hepatitis). Cytomegalovirus, Epstein-Barr virus, and herpes simplex virus may also occasionally cause hepatitis. Some forms of hepatitis carry the risks of chronic infection, cirrhosis, or hepatocellular carcinoma. Treatment options for viral hepatitis are limited and, in many cases, still under investigation. Prophylaxis is available for many forms of hepatitis and should be offered to those at risk.

Review article: the management of hepatitis A, B, D and non-A non-B

This paper reviews the modern management of viral hepatitis: hepatitis A, hepatitis B, hepatitis D and non-A non-B hepatitis. It describes the treatment of uncomplicated acute viral hepatitis, complicated acute viral hepatitis, and chronic viral hepatitis. The roles for corticosteroids, synthetic nucleotides, and interferons are reviewed. Finally, passive and active immunization against viral hepatitis are discussed.