Antigen-specific T lymphocyte proliferation decreases over time in advanced chronic hepatitis C.

To evaluate T cell immunity in advanced liver disease, antigen-specific lymphoproliferative (LP) responses were prospectively studied in the context of the Hepatitis C Antiviral Long-term Treatment against Cirrhosis trial. Peripheral blood responses to hepatitis C virus (HCV), tetanus and Candida protein antigens were measured at baseline, month 12 (M12), M24, M36 and M48 in 186 patients randomized to either low-dose peginterferon-alfa-2a (PEG-IFN) only or observation. Liver histology was evaluated at baseline, M24 and M48. Patients with cirrhosis (Ishak 5-6) were less likely to have positive LP responses to HCV at baseline than patients with fibrosis (15%vs 29%, P = 0.03) and had lower levels of HCV c100 responses at baseline, M24 and M48 (P = 0.11, P = 0.05, P = 0.02, respectively). For 97 patients with complete longitudinal data, the frequency of positive LP responses to HCV, tetanus and Candida antigens declined over time (P < 0.003), and the slope of this decline was greater in the PEG-IFN treatment group than the observation group (P < 0.02). Lower levels of tetanus LP responses were associated with fibrosis progression and clinical outcomes (P = 0.009). Poorer CD4+ T cell proliferative function was associated with more advanced liver disease in chronic hepatitis C and may be further affected by long-term PEG-IFN treatment.

Silymarin use and liver disease progression in the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis trial.

BACKGROUND: Silymarin is the most commonly used herbal product for chronic liver disease; yet, whether silymarin protects against liver disease progression remains unclear. AIM: To assess the effects of silymarin use on subsequent liver disease progression in 1049 patients of the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis (HALT-C) trial who had advanced fibrosis or cirrhosis and had failed prior peginterferon plus ribavirin treatment. METHODS: Patients recorded their use of silymarin at baseline and were followed up for liver disease progression (two point increase in Ishak fibrosis score across baseline, year 1.5, and year 3.5 biopsies) and over 8.65 years for clinical outcomes. RESULTS: At baseline, 34% of patients had used silymarin, half of whom were current users. Use of silymarin was associated (P < 0.05) with male gender; oesophageal varices; higher ALT and albumin; and lower AST/ALT ratio, among other features. Baseline users had less hepatic collagen content on study biopsies and had less histological progression (HR: 0.57, 95% CI: 0.33-1.00; P-trend for longer duration of use=0.026). No effect was seen for clinical outcomes. CONCLUSIONS: Silymarin use among patients with advanced hepatitis C-related liver disease is associated with reduced progression from fibrosis to cirrhosis, but has no impact on clinical outcomes (Clinicaltrials.gov #NCT00006164).

Clinical use of hepatitis C virus tests for diagnosis and monitoring during therapy.

This article reviewed various methods used for the diagnosis and monitoring of HCV infection and discusses potential clinical applications. Substantial improvements have recently been made in assay technology. Moreover, the role of molecular testing in the clinical setting of hepatitis C is becoming better defined. The major challenge facing clinical laboratories is the further refinement, implementation, and standardization of optimized molecular tests, so that reliable data may be made available to clinicians. In turn, clinicians must understand the limitations of each methodology, including the variability of testing that may occur among different laboratories. As more experience is gathered, molecular testing will probably provide important data regarding the most effective use of current and future therapies for individual patients to achieve maximum benefit in the management of hepatitis C.

Expression of two structurally identical viral superantigens results in thymic elimination at distinct developmental stages.

Mouse mammary tumor virus proviral integrants encode superantigens. Developing thymocytes bearing TCRs with particular V beta elements encounter these endogenous viral superantigens as self molecules in the thymus and are consequently clonally eliminated. To study this mechanism of tolerance induction, we have bred B10.BR-Mtv-1 and B10.BR-Mtv-6 mice, which carry either Mtv-1 or Mtv-6 proviruses but are otherwise genetically identical. The protein products of these mouse mammary tumor virus integrants, vSAG1 and vSAG6, both interact with V beta 3+ T cells and have identical amino acid sequences. Interestingly, vSAG6 expression results in the complete deletion of V beta 3+ peripheral T cells, whereas vSAG1 expression results in only partial deletion. Flow cytometric analyses indicate that B10.BR-Mtv-6 mice delete V beta 3+ thymocytes at the immature CD4+8+ stage, whereas B10.BR-Mtv-1 mice delete only mature CD4+ or CD8+ cells. In addition, the two strains exhibit different time courses of thymic deletion: neonatal B10.BR-Mtv-6 mice eliminate V beta 3+ T cells by day 2, in contrast to B10.BR-Mtv-1 mice in which deletion does not occur until day 15. RNase protection assays demonstrate that B10.BR-Mtv-6 mice have significantly greater thymic vSAG6 mRNA expression levels than vSAG1 levels in B10.BR-Mtv-1 animals, correlating with a more complete deletion of reactive thymocytes at an earlier point in the maturational sequence.

Growth factor-induced acceleration of tissue repair through direct and inductive activities in a rabbit dermal ulcer model.

The roles of polypeptide growth factors in promoting wound healing and in directing the specificity and sequence of responses of different tissues in wounds are little understood. We investigated the influence of four growth factors on the rates of healing of a novel full thickness dermal ulcer placed on an avascular base in the rabbit ear. The wound model precludes significant wound contraction and requires new granulation tissue and epithelial cells for healing to originate centripetally. 5 micrograms (7-31 pmol/mm2) of platelet-derived growth factor-B chain (PDGF-BB), basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF) applied locally at the time of wounding resulted in a twofold increase in complete reepithelialization of treated wounds (PDGF-BB, P = 0.02 chi square analysis; bFGF, P = 0.04; EGF, P = 0.05); transforming growth factor (TGF)-beta 1 significantly inhibited reepithelialization (P = 0.05). Both PDGF-BB and TGF-beta 1 uniquely increased the depth and area of new granulation tissue (P less than 0.005), the influx of fibroblasts, and the deposition of new matrix into wounds. Explants from 7-d old PDGF-BB-treated wounds remained metabolically far more active than controls, incorporating 473% more [3H]thymidine into DNA (P = 0.05) and significantly more [3H]leucine and [3H]proline into collagenase-sensitive protein (P = 0.04). The results establish that polypeptide growth factors have significant and selective positive influences on healing of full thickness ulcers in the rabbit.

Structural requirements for sulfation of asparagine-linked oligosaccharides of lutropin.

Human and bovine pituitary glycoprotein hormones (lutropin, follitropin, and thyrotropin) contain varying amounts of N-acetylgalactosamine and sulfate. The sulfate on asparagine-linked oligosaccharides of bovine lutropin (bLH) is present exclusively on GalNAc in the sequence GalNAc(beta 1-4)GlcNAc(beta 1-2)Man alpha. We have examined the structural requirements for sulfation of bLH oligosaccharides by using a reconstituted cell-free system. After cleavage from the protein, oligosaccharides containing the sequence GalNAc(beta 1-4)Glc-NAc(beta 1-2)Man alpha were sulfated by enzymes in pituitary membranes. Addition of one or two sulfates was observed, depending upon the number of GalNAc acceptor sites on the oligosaccharide. Neither GalNAc alone nor oligosaccharides devoid of GalNAc were sulfated. Membranes from placenta or liver did not sulfate oligosaccharides released from bLH, indicating that the sulfating activity is pituitary-specific. The lack of peptide dependence for sulfation, in conjunction with the oligosaccharide specificity, suggests that the sequence GalNAc(beta 1-4)GlcNAc(beta 1-2)Man alpha contains the recognition signal for the sulfotransferase(s).