Tracking the source of the hepatitis B virus-specific CD8 T cells during lamivudine treatment

Lamivudine treatment in chronic hepatitis B leads to the reconstitution of virus-specific T cells in the circulation, but it is not clear whether this is the preferential result of T cell efflux from the liver or lymph nodes. To address this question, the frequency and function of liver-, lymph node-, and blood-derived hepatitis B virus (HBV)-specific CD8 T cells were analyzed in patients treated with lamivudine and undergoing liver transplantation. HBV-specific CD8 T cells, identified in portal lymph nodes, were able to expand in vitro after antigen-specific stimulation and displayed a heterogeneous profile of cytokine production. These findings suggest that the peripherally reconstituted HBV-specific CD8 T cells can originate from precursor cells within lymph nodes

The endoscopist and malignant and non-malignant biliary obstruction

Patients with biliary strictures often represent a diagnostic and therapeutic challenge, due to the site and complexity of biliary obstruction and wide differential diagnosis. Multidisciplinary decision making is required to reach an accurate and timely diagnosis and to plan optimal care. Developments in endoscopic ultrasound and peroral cholangioscopy have advanced the diagnostic yield of biliary endoscopy, and novel optical imaging techniques are emerging. Endoscopic approaches to biliary drainage are preferred in most scenarios, and recent advances in therapeutic endoscopic ultrasound allow drainage where the previous alternatives were only percutaneous or surgical. Here we review recent advances in endoscopic practice for the diagnosis and management of biliary strictures. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni and Peter Jansen

The role of multidisciplinary meetings for benign pancreatobiliary diseases: a tertiary centre experience

Multidisciplinary meetings are central to the management of chronic and complex diseases and they have become widely established across the modern healthcare. Patients with pancreatobiliary diseases can often present with complex clinical dilemmas, which fall out with the scope of current guidelines. Therefore, these patients require a personalised management approach discussed in a multidisciplinary meeting

Preventing Post-ERCP Pancreatitis: The Role of Prophylactic Pancreatic Duct Stenting in the Rectal NSAID Era

Background: Rectal non-steroidal anti-inflammatory drug at endoscopic retrograde cholangiopancreatography is now the standard of care to reduce the risk of post-ERCP pancreatitis. Pancreatic duct stenting also reduces the risk of post- ERCP pancreatitis in high-risk patients, but failed pancreatic duct stenting carries an increased PEP rate (up to 35%). Study Aim: To assess the impact on post-ERCP pancreatitis of successful and unsuccessful pancreatic duct stent placement in the setting of universal rectal non-steroidal anti-inflammatory drug use. Methods: Between 2013-2015, all patients undergoing endoscopic retrograde cholangiopancreatographys in our tertiary referral centre (where rectal non-steroidal anti-inflammatory drugs are used routinely) were included. The electronic patient's records were reviewed and the following parameters were analysed: indication for pancreatic duct stenting; deployment success; and adverse events. Results: A total of 1633 endoscopic retrograde cholangiopancreatographys were performed, and pancreatic duct stenting was attempted in 324 cases (20%), with successful placement in 307 patients (95%). Contra-indications to non-steroidal anti-inflammatory drugs were found in 106 (6.5%) patients. Prophylactic stenting failed in 12 of 213 patients; of whom one patient developed post-ERCP pancreatitis (8%). Eighteen (9%) patients with prophylactic pancreatic duct stents developed post-ERCP pancreatitis compared to 1.4% without prophylactic stents (RR 8.4, p=0.04). Conclusion: A lack of difference in post-ERCP pancreatitis in those who underwent successful, and unsuccessful, pancreatic duct stent placement may reflect the protective effect of non-steroidal anti-inflammatory drugs. This data adds to evidence suggesting that pancreatic duct stenting may be less important, even in high-risk patients, with the widespread use of non-steroidal anti-inflammatory drugs

The third signal cytokine IL-12 rescues the anti-viral function of exhausted HBV-specific CD8 T cells.

Optimal immune activation of naïve CD8 T cells requires signal 1 mediated by the T cell receptor, signal 2 mediated by co-stimulation and signal 3 provided by pro-inflammatory cytokines. However, the potential for signal 3 cytokines to rescue anti-viral responses in functionally exhausted T cells has not been defined. We investigated the effect of using third signal cytokines IL-12 or IFN-α to rescue the exhausted CD8 T cell response characteristic of patients persistently infected with hepatitis B virus (HBV). We found that IL-12, but not IFN-α, potently augmented the capacity of HBV-specific CD8 T cells to produce effector cytokines upon stimulation by cognate antigen. Functional recovery mediated by IL-12 was accompanied by down-modulation of the hallmark inhibitory receptor PD-1 and an increase in the transcription factor T-bet. PD-1 down-regulation was observed in HBV but not CMV-specific T cells, in line with our finding that the highly functional CMV response was not further enhanced by IL-12. IL-12 enhanced a number of characteristics of HBV-specific T cells important for viral control: cytotoxicity, polyfunctionality and multispecificity. Furthermore, IL-12 significantly decreased the pro-apoptotic molecule Bim, which is capable of mediating premature attrition of HBV-specific CD8 T cells. Combining IL-12 with blockade of the PD-1 pathway further increased CD8 functionality in the majority of patients. These data provide new insights into the distinct signalling requirements of exhausted T cells and the potential to recover responses optimised to control persistent viral infections

Synthesis and Self-Assembly of Well-Defined Block Copolypeptides via Controlled NCA Polymerization

This article summarizes advances in the synthesis of well-defined polypeptides and block copolypeptides. Traditional methods used to polymerize α-amino acid-N-carboxyanhydrides (NCAs) are described, and limitations in the utility of these systems for the preparation of polypeptides are discussed. Improved initiators and methods that allow polypeptide synthesis with good control over chain length, chain length distribution, and chain-end functionality are also discussed. Using these methods, block and random copolypeptides of controlled dimensions (including molecular weight, sequence, composition, and molecular weight distribution) can now be prepared. The ability of well-defined block copolypeptides to assemble into supramolecular copolypeptide micelles, copolypeptide vesicles, and copolypeptide hydrogels is described. Many of these assemblies have been found to possess unique properties that are derived from the amino acid building blocks and ordered conformations of the polypeptide segments. © Springer-Verlag Berlin Heidelberg 2013

T cell receptor usage of virus-specific CD8 cells and recognition of viral mutations during acute and persistent hepatitis B virus infection

T cells specific for a single viral epitope, but using different T cell receptors, should have flexibility in their epitope recognition to protect the infected host against the emergence of viral escape mutants. Therefore, polyclonality of the hepatitis B virus (HBV)-specific cytotoxic T lymphocyte response has been hypothesized to be a major determinant in the control of infection. We analyzed the V beta chain composition of the core 18-27-specific GD8 cells in acute and persistently HBV-infected patients using HLA-A2 tetrameric complexes and a panel of V beta antibodies. Different T cell receptors were utilized by core 18-27-specific CD8 cells both in patients with acute and chronic infection. The functional ability of these epitope-specific T cells to respond to potential viral mutations was then tested. The polyclonal HBV-specific CD8 response present in patients with acute hepatitis displayed a limited efficiency to recognize mutations introduced within the epitope. The ability of core 18-27-specific CD8 to tolerate epitope mutations was found only during persistent HBV infection. The data suggest that although a clonally heterogeneous CD8 response can be largely inhibited by the occurrence of single epitope mutations in primary HBV infection, preferential selection of T cells able to counteract the emergence of viral mutations can occur during persistent infection