Polyethylene glycol-interferon: current status in hepatitis C virus therapy

Pancreas and Adverse Drug Reactions: A Literature Review

Adverse drug reactions (ADRs) affecting the pancreas are a heterogeneous group of side effects that cause damage to pancreatic cells. Various mechanisms such as hypersensitization, sphincter of Oddi constriction, direct cytotoxic and metabolic effects on pancreatic cells, and dose-dependent idiosyncrasy lead to intrapancreatic activation of pancreatic enzymes resulting in drug-induced acute pancreatitis. Several medications have been linked with the development of pancreatic cancer. Pancreatic cancer may result from proinflammatory, proliferative, and antiapoptotic effects. Diabetogenic effect of drugs, which is understood as impairment of insulin secretion, may occur due to direct destruction of β cells, systemic toxicity affecting pancreatic islets and cell membrane glucose transporters, induction of Th1-type autoimmune response, and impairment of voltage-gated calcium channels in β cells, endoplasmic reticulum stress, and insulin signaling. A better understanding of ADRs that affect the pancreas may contribute to improving the awareness of clinicians and patients and reducing potential harmful side effects of implemented therapies.

Suppressor of cytokine signal 3 and IL28 genetic variation predict the viral response to peginterferon and ribavirin

AIM

  The aim of this study was to investigate the relationship among the expression of suppressor of cytokine signaling 3 (SOCS 3) in the liver, the SNPs in the IL28B locus, and the outcome of interferon therapy.

METHODS

  Prior to interferon treatment, we immunostained 67 liver specimens from chronic hepatitis C (CHC) patients who were receiving peginterferon alpha-2b/ribavirin therapy for suppressor of cytokine signaling 3 (SOCS3), and compared the expression of SOCS3, IL28 polymorphisms and other clinical factors between the patients and compared their eventual outcomes.

RESULTS

  Significant differences between the low SOCS3 group and high SOCS3 group were found in age, as well as in the platelet, transaminase, gamma-glutamyl transpeptidase levels. The incidence of high SOCS3 was not significantly different between subjects with the TT genotype and the TG genotype (TT : TG = 71%:29%, P = 0.250). In a multivariate analysis, age (≥65 years old) (odds ratio 0.221 [0.120-0.966], P = 0.045), IL28B gene (genotype TT) (odds ratio 5.422 [1.254-23.617], P = 0.024) and SOCS3 (high) (odds ratio 0.308 [0.104-0.948], P = 0.040) were significant predictors of the interferon response. In patients with the TT genotype, those with low SOCS3 immunostaining showed a high sustained virological response (69%), while the sustained virological rate was low (27%) in the patients with high SOCS3 immunostaining.

CONCLUSIONS

  Using a combination of the SOCS3 immunostained area in the liver and the expression of IL28B single nucleotide polymorphisms might be a useful predictor of hepatitis C virus clearance by interferon therapy.

Type 1 diabetes and interferon therapy: a nationwide survey in Japan

OBJECTIVE

Interferon therapy can trigger induction of several autoimmune diseases, including type 1 diabetes. To assess the clinical, immunologic, and genetic characteristics of type 1 diabetes induced by interferon therapy, we conducted a nationwide cross-sectional survey.

RESEARCH DESIGN AND METHODS

Clinical characteristics, anti-islet autoantibodies, and HLA-DR typing were examined in 91 patients for whom type 1 diabetes developed during or shortly after interferon therapy.

RESULTS

Median age at the onset of type 1 diabetes was 56 (interquartile range 48-63) years and mean ± SD BMI was 20.8 ± 2.7 kg/m(2). The time period from the initiation of interferon therapy to type 1 diabetes onset in patients receiving pegylated interferon and ribavirin was significantly shorter than that in patients with nonpegylated interferon single therapy (P < 0.05). Anti-islet autoantibodies were detected in 94.5% of patients at diabetes onset. Type 1 diabetes susceptibility HLA-DRs in the Japanese population, DR4 and DR9, were also associated with interferon treatment-related type 1 diabetes. Furthermore, the prevalence of HLA-DR13 was significantly higher in interferon treatment-related type 1 diabetes than in healthy control subjects (odds ratio 3.80 [95% CI 2.20-7.55]; P < 0.0001) and classical type 1 diabetes (2.15 [1.17-3.93]; P < 0.05).

CONCLUSIONS

Anti-islet autoantibodies should be investigated before and during interferon therapy to identify subjects at high risk of type 1 diabetes. Stronger antiviral treatment may induce earlier development of type 1 diabetes. Furthermore, patients who develop interferon-induced type 1 diabetes are genetically susceptible.

Direct effects of type I interferons on cells of the immune system

Type I interferons (IFN-I) are well-known inducers of tumor cell apoptosis and antiangiogenesis via signaling through a common receptor interferon alpha receptor (IFNAR). IFNAR induces the Janus activated kinase-signal transducer and activation of transcription (JAK-STAT) pathway in most cells, along with other biochemical pathways that may differentially operate, depending on the responding cell subset, and jointly control a large collection of genes. IFNs-I were found to systemically activate natural killer (NK) cell activity. Recently, mouse experiments have shown that IFNs-I directly activate other cells of the immune system, such as antigen-presenting dendritic cells (DC) and CD4 and CD8 T cells. Signaling through the IFNAR in T cells is critical for the acquisition of effector functions. Cross-talk between IFNAR and the pathways turned on by other surface lymphocyte receptors has been described. Importantly, IFNs-I also increase antigen presentation of the tumor cells to be recognized by T lymphocytes. These IFN-driven immunostimulatory pathways offer opportunities to devise combinatorial immunotherapy strategies.

Predictive value of suppressor of cytokine signal 3 (SOCS3) in the outcome of interferon therapy in chronic hepatitis C

AIMS

Suppressor of cytokine signaling 3 (SOCS3) can suppress Janus kinase (JAK)-signal transducers and activators of transcription (STAT) signaling by blocking an IFN-induced protein. In this study, the relationship between SOCS3 and phosphorylation of STAT1 in the liver and outcome of interferon therapy were examined.

METHODS

Prior to interferon treatment, we immunostained for SOCS3 and phosphorylated-STAT1 (P-STAT1) in 59 liver specimens from chronic hepatitis C virus (CHC) patients and compared the expression of SOCS3 and clinicopathological factors. Fifty-one patients were receiving peg-interferon alpha-2b and ribavirin therapy and also compared interferon therapy effect and the expression of SOCS3.

RESULTS

Immunostaining for SOCS3 was mainly seen in the periportal area. The concentration of P-STAT1 nuclei was significantly larger in specimens with < 30% area immunostaining to SOCS3 than those in which this area was >/= 30% (10.6 +/- 8.8 vs. 4.6 +/- 6.1, P = 0.004). SOCS3 immunostaining score was significantly correlated with aspartate amino transferase (r = 0.373, P = 0.003), alanine amino transferase (r = 0.337, P = 0.008), platelets (r = -0.273, P = 0.037), and homeostatic model assessment (r = 0.339, P = 0.008). On univariate analysis and multivariate analysis, SOCS3 immunostaining score (0 or 1) and age (<60 years old) were significant predictors of interferon response (odds ratio 10.888; P = 0.010; odds ratio 3.817, P = 0.045 respectively).

CONCLUSION

SOCS3 expression in the liver prior to interferon therapy was correlated with increased insulin resistance and might be a useful predictor of HCV clearance by interferon therapy.

Impaired TRAIL-dependent cytotoxicity of CD1c-positive dendritic cells in chronic hepatitis C virus infection

Dendritic cells (DCs) play a central role in antiviral immunity. Conflicting data on DC function have been reported for hepatitis C virus (HCV) infection. In addition to antigen presentation and cytokine secretion, a subset of human DCs displays direct cytotoxic activity. It has been suggested that measles virus and human immunodeficiency virus (HIV) may enhance cytotoxicity of DCs potentially leading to apoptosis of activated T cells and subsequent down-regulation of antiviral immune responses. We demonstrate that CD1c-positive myeloid DCs, but not BDCA-4-positive plasmacytoid DCs, are able to kill different target cells mainly via tumour necrosis factor-related apoptosis-inducing ligand. The ability of CD1c+ DCs to lyze target cells was found to be completely impaired in patients with chronic hepatitis C (10 chronic HCV patients vs 10 healthy controls; P < 0.001) but not in patients with primary biliary cirrhosis. Successful antiviral therapy of chronic hepatitis C rescued the cytotoxicity of DCs. Myeloid DCs of HCV patients and healthy controls had a similar phenotype and endocytotic activity, however, the frequency of mDCs in the peripheral blood was lower (P = 0.004) and the allostimulatory function was weaker (P < 0.001) in chronic hepatitis C. Thus, in contrast to HIV and measles virus studies on monocyte-derived DCs, freshly isolated myeloid DCs of patients with hepatitis C do not show an increased but a completely abolished cytotoxic activity. The impaired DC cytotoxicity could represent a novel mechanism for the increased prevalence of autoimmunity in HCV infection.

Tailoring structure-function properties of L-asparaginase: engineering resistance to trypsin cleavage

Bacterial L-ASNases (L-asparaginases) catalyse the conversion of L-asparagine into L-aspartate and ammonia, and are widely used for the treatment of ALL (acute lymphoblastic leukaemia). In the present paper, we describe an efficient approach, based on protein chemistry and protein engineering studies, for the construction of trypsin-resistant PEGylated L-ASNase from Erwinia carotovora (EcaL-ASNase). Limited proteolysis of EcaL-ASNase with trypsin was found to be associated with a first cleavage of the peptide bond between Lys53 and Gly54, and then a second cleavage at Arg206-Ser207 of the C-terminal fragment, peptide 54-327, showing that the initial recognition sites for trypsin are Lys53 and Arg206. Site-directed mutagenesis of Arg206 to histidine followed by covalent coupling of mPEG-SNHS [methoxypoly(ethylene glycol) succinate N-hydroxysuccinimide ester] to the mutant enzyme resulted in an improved modified form of EcaL-ASNase that retains 82% of the original catalytic activity, exhibits enhanced resistance to trypsin degradation, and has higher thermal stability compared with the wild-type enzyme.

Treatment of hepatitis C virus-associated inflammatory polyneuropathy with pegylated interferon-alpha and ribavirin

Peripheral neuropathy is common in patients with hepatitis C virus infection and cryoglobulinemia. Here, we report a patient with axonal polyneuropathy associated with type III mixed cryoglobulinemia and hepatitis C virus infection without significant liver disease, who was successfully treated with pegylated interferon-alpha-2a and ribavirin. This case illustrated that clinical improvement was paralleled by a decrease of cryocrit but not necessarily by a decrease of viral replication rate. Treatment of hepatitis C virus-cryoglobulinemia-associated neuropathy should therefore be continued even if response of viral replication is lacking or delayed as long as a clinical benefit can be observed.

Recombinant human interferon-alpha does not alter reward behavior, or neuroimmune and neuroendocrine activation in rats

Recombinant human interferon-alpha (IFN-alpha) induces depression, and neuroendocrine and neuroimmune activation, in a significant number of patients undergoing treatment for viral illnesses (e.g., hepatitis C), yet these effects have not been consistently reproduced in rodents. As such, we sought to determine the effects of acute or chronic IFN-alpha treatment on basic reward and immobility in the forced swim test (FST), neuroendocrine and neuroimmune activation, and monoamine turnover in brain. In the first experiment, male Wistar rats (N = 7/group) treated with human recombinant IFN-alpha (100,000 IU/kg, i.p.), as compared to saline, did not exhibit alterations to rate of sucrose pellet self-administration or total reinforcers obtained, corticosterone release, plasma IL-6 release, IL-1beta or IL-6 mRNA expression in hippocampus, or monoamine turnover in prefrontal cortex, striatum, nucleus accumbens, or amygdala. However, acute IFN-alpha decreased body weight and produced a trend toward reduced food consumption in the home cage 2 h after injection. In the second experiment, Wistar rats (N=4/group) were subjected to a chronic treatment regimen of saline or IFN-alpha (100,000 IU/kg, i.p.) once daily for 14 consecutive days. The data reveal that animals exposed to chronic IFN-alpha exhibited similar amounts of time immobile and similar latencies to primary immobility in the FST as compared to saline-treated controls. Chronic IFN-alpha did not induce corticosterone release, plasma TNF-alpha, or IL-6 release. Tissue monoamine analysis revealed that chronic IFN-alpha reduced DA levels in prefrontal cortex, and decreased 5-HT levels and increased 5-HT turnover in amygdala. In the third experiment, Wistar rats (N = 4/group) were exposed to either acute or chronic pegylated IFN-alpha (pegIFN-alpha: 3.25, 10 or 75 mg/kg, i.p.) at one of several time points from 1 h to 23 days. The data reveal that neither acute nor chronic pegIFN-alpha induced corticosterone release. Overall, the current report demonstrates that neither acute nor chronic IFN-alpha induced depressive-like behavior and neither IFN-alpha nor peg-IFN-alpha was capable of inducing neuroendocrine or neuroimmune activation. Despite the neurochemical alterations observed in the chronic treatment regimen, the data indicate that recombinant human IFN-alpha does not produce a robust model of depressive-like behavior in rodents.

High rate of spontaneous clearance of acute hepatitis C virus genotype 3 infection

Treating acute hepatitis C with interferon alpha prevents chronicity in nearly all cases when therapy is initiated within 3 months after infection. However, 15-50% of untreated patients may clear the hepatitis C virus (HCV) spontaneously. Therefore, factors are needed to identify patients prior to therapy who have a higher or lower risk for developing a chronic course to avoid unnecessary treatment. The role of the HCV genotype for spontaneous recovery from acute hepatitis C has been discussed controversially. In the year 2002, all 1,176 new incoming prisoners in a Northern German prison for young men (age 16-24) were screened for anti-HCV antibodies and 92 tested positive. Ninety eight percent of these reported i.v.-drug abuse for a median of 32 months prior to imprisonment. HCV-RNA negative individuals (21%) were serotyped and HCV-RNA positive patients were genotyped. The prevalence of HCV genotype 3 was significantly higher among individuals who had cleared HCV spontaneously as compared to chronically infected patients (86% vs. 38%; P = 0.002). Ninety three percent of individuals exposed to HCV genotype 1 but only 63% of individuals exposed to genotype 3 experienced a chronic course of the infection (P = 0.006). Thus, acute infection in young Caucasian men with HCV genotype 3 leads more often to spontaneous clearance than infection with HCV genotype-1. Considering also the high chance of successful treatment of chronic HCV genotype 3 infection with pegylated-interferon in combination with ribavirin, we suggest not to treat acute hepatitis C genotype 3 infection early but rather to wait at least 3 months after the onset of symptoms when chronicity becomes likely.

Prevention of hepatitis C virus infection

In spite of advances made in our understanding of the biology of the hepatitis C virus (HCV), the epidemiology and natural history of HCV infection, and the treatment of chronic hepatitis C, the development and worldwide implementation of a comprehensive prevention and control strategy remains necessary. A World Health Organization informal consultation with the Viral Hepatitis Prevention Board was convened and met in Geneva, Switzerland, 13-14 May 2002, to review epidemiological and public health aspects of HCV infection, and the various prevention and control strategies that are currently in place. Based on the presentations and discussions, a number of specific recommendations were made, which should be considered in conjunction with previously published recommendations.