Project description:Background: Hepatitis E Virus (HEV) is a new causative agent of chronic hepatitis in solid organ transplant recipients in Europe. Factors associated with the occurrence and persistence of chronic HEV infection remain largely unknown but chronic evolution seems to be the consequence of hostM-bM-^@M-^Ys immunological factors rather than of viral factors. Method: In a prospective case-control study, we have determined in whole blood of chronically HEV-infected kidney-transplant recipients the host response using microarray technology. Results: Chronically HEV-infected kidney-transplant recipients exhibited a specific transcriptional program, in which interferon effectors were prominent. The intensity of expression of each signatureM-bM-^@M-^Ys gene was significantly lower in patients who were subsequently cleared of HEV than in patients who were not. Furthermore, in patients who were cleared of HEV, a higher expression of these genes was associated with a longer delay until HEV clearance. Conclusions: The specific transcriptional program determined in chronically HEV-infected kidney-transplant recipients suggests an activation of type I interferon response. Intensity of interferon-stimulated genes expression could be useful to forecast the outcome of infection. High expression of interferon-stimulated genes could signify a dysregulation in the interferon response that might favour the persistence of the HEV infection. TrialM-bM-^@M-^Ys registration number: NCT01090232; RegistryM-bM-^@M-^Ys URL: http://clinicaltrials.gov/ct2/show/study/NCT01090232?term=kidney+transplant+recipients&cntry1=EU%3AFR&rank=2 Total RNA was extracted from whole-blood sample or monocytes of kidney-transplant patients with or without chronic hepatitis E (CHE) infection. Control patients were matched up with CHE patients for age, sex, time since kidney transplant and immunosuppressive treatment.
Project description:<p>Reprinted from http://www.haltctrial.org/</p> <p><b>Purpose</b></p> <p>The <b>H</b>epatitis C <b>A</b>ntiviral <b>L</b>ong-term <b>T</b>reatment against <b>C</b>irrhosis (HALT-C) Trial is a randomized controlled trial designed to evaluate the safety and efficacy of long-term use of pegylated interferon for the treatment of chronic hepatitis C in patients who failed to respond to previous interferon therapy. The HALT-C Trial was developed to determine whether prolonged interferon therapy altered histological and clinical outcomes in a group of patients who had failed to eradicate hepatitis C virus with previous interferon treatment.</p> <p><b>Study Hypotheses</b></p> <p> <ol> <li>In patients with chronic hepatitis C and bridging fibrosis who failed to eradicate the virus with previous interferon therapy, long-term treatment with interferon is safe and can prevent progression to cirrhosis.</li> <li>In patients with cirrhosis secondary to chronic hepatitis C who failed to eradicate the virus with previous interferon therapy, long-term treatment with interferon is safe and can reduce the risks of hepatic decompensation or of hepatocellular carcinoma.</li> </ol> </p> <p><b>Study Design</b></p> <p>1145 patients with chronic HCV and advanced hepatic fibrosis (Ishak stage 3-6) who failed to respond to previous treatment with interferon were enrolled at 10 clinical centers and entered into a Lead-in phase. They were treated with a combination of pegylated interferon (Pegasys®, Hoffmann-La Roche) 180 µg/week and ribavirin (1000-1200 mg/day) for 24 weeks. Patients who had no detectable HCV-RNA at week 20 continued on combination therapy until week 48.</p> <p>662 patients who did not clear virus were randomly assigned at week 24 to either continue treatment with pegylated interferon alone (90 µg/week) for an additional 42 months, or to have treatment discontinued. All patients were followed at 3-month intervals following randomization. Liver biopsy was performed at baseline and after 1.5 and 3.5 years of treatment.</p> <p>Because of slower than expected enrollment and the approval by the FDA of peginterferon alfa-2b after the start of the trial, we modified the study protocol in three ways. First, criteria for admission to the trial were liberalized to allow patients to enter the trial with lower platelet and white blood cell counts than had been initially considered safe or tolerable. Second, 151 Lead-in patients and those continuing on therapy after 24 weeks who demonstrated return of viremia during or after their 48-week treatment period (called "Breakthrough" or "Relapse" patients, respectively) were allowed to return to enter the randomized trial. Third, 237 patients treated with peginterferon alfa-2b (or with peginterferon alfa-2a in licensing trials) outside the HALT-C Trial who in other respects met all study criteria, having received the equivalent of Trial Lead-in period therapy, were allowed to enter the long-term trial as "Express" patients.</p> <p>A total 1050 patients were randomized.</p> <p>Those patients who completed Month 48 were offered an "extended follow-up (observation only)" until October 2009. These visits will primarily be to identify outcome events, and to provide information to patients concerning the current status of the trial. Some questionnaires, blood tests, and an ultrasonogram will be performed.</p> <p><u>Quarterly (every 3 months)</u></p> <p> <ul> <li>Interval history of complications, adverse events</li> <li>Current medications</li> <li>Brief physical examination</li> <li>Laboratory tests: liver panel, CBC, INR, AFP</li> <li>Child-Pugh Score</li> <li>Stored serum</li> </ul> </p> <p><u>Annual</u></p> <p> <ul> <li>Complete physical examination</li> <li>Ultrasound of liver</li> </ul> </p> <p><u>1.5 years (M24 visit, middle of study)</u></p> <p> <ul> <li>Liver biopsy: formalin fixed histology, frozen liver tissue (subset of patients)</li> </ul> </p> <p><u>3.5 years (M48, end of study)</u></p> <p> <ul> <li>Liver biopsy: formalin fixed histology, frozen liver tissue (subset of patients)</li> <li>Endoscopy: evaluate esophageal varices and portal hypertension</li> </ul> </p> <p><u>After Month 48</u></p> <p> <ul> <li>Observation only (no treatment) to determine clinical outcomes</li> <li>Clinic visit every 6 months with current medications, brief PE, liver panel, CBC, AFP, stored</li> <li>Serum</li> <li>Ultrasound of liver every 6 months</li> </ul> </p> <p><b>Outcome Variables</b></p> <p>Primary outcome variables to be assessed in the two groups of patients include: <ul> <li>Development of cirrhosis on liver biopsy (progression of Ishak fibrosis score by 2 points or more)</li> <li>Development of hepatic decompensation, as shown by:</li> <ul> <li>Sustained increase in the Child-Turcotte-Pugh score to 7 points or higher</li> <li>Variceal hemorrhage</li> <li>Ascites</li> <li>Spontaneous bacterial peritonitis</li> <li>Hepatic encephalopathy</li> <li>Development of hepatocellular carcinoma</li> <li>Death</li> </ul> </ul> Secondary outcomes include quality of life, serious adverse events, events requiring dose reductions, and development of presumed hepatocellular carcinoma. </p>
Project description:Approximately 50% of patients with chronic hepatitis C (CHC) have a sustained virologic response (SVR) to treatment with pegylated interferon (pegINF)-α and ribavirin. Non-response to treatment is associated with constitutively increased expression of IFN-stimulated genes (ISGs) in the liver. Treatment of patients with acute hepatitis C (AHC) is more effective, with SVR rates >90%. We investigated mechanisms of the different responses of patients with CHC and AHC to pegIFN-α therapy. We analyzed IFN signaling and ISG expression in liver samples from patients with acute hepatitis C (AHC), patients with chronic hepatitis (CHC), and individuals without hepatitis C (controls) using microarray, immunohistochemical, and protein analyses. Findings were compared with those from primary human hepatocytes stimulated with IFN-α or IFN-γ, as reference sets. Expression levels of 100s of genes, primarily those regulated by IFN-γ, were altered in liver samples from patients with AHC compared with controls. Expression of IFN-γ–stimulated genes was induced in liver samples from patients with AHC, whereas expression of IFN-α–stimulated genes was induced in samples from patients with CHC. In an expression analysis of negative regulators of IFN-α signaling, we did not observe differences in expression of SOCS1 or SOCS3 between liver samples from patients with AHC and those with CHC. However, USP18 (another negative regulator of IFN-α signaling), was upregulated in liver samples of patients with CHC that did not respond to therapy, but not in AHC. In conclusion, differences in expression of ISGs might account for the greater response of patients with AHC, compared to those with CHC, to treatment with pegINF-α and ribavirin. Specifically, USP18 is upregulated in liver samples of patients with CHC that do not respond to therapy, but not in patients with AHC. (Interferon-γ Stimulated Genes, but not USP18, are Expressed in Livers of Patients with Acute Hepatitis C; Dill MT, Makowska Z et al, Gastroenterology 2012 (in press)) Primary human hepatocytes from 2 donors were analyzed. From each donor there are 5 samples: untreated cells, cells treated with interferon alpha (1000 IU/ml) for 6 and 24 hours and cells treated with interferon gamma (1000 IU/ml) for 6 and 24 hours.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.