No abstract

Impaired activity of natural killer cells has been proposed as a mechanism contributing to viral persistence in hepatitis C virus (HCV) infection. Natural cytotoxicity is regulated by interactions of HLA-E with inhibitory CD94/NKG2A receptors on natural killer (NK) cells. Here, we studied whether HCV core encodes peptides that bind to HLA-E and inhibit natural cytotoxicity. We analyzed 30 HCV core-derived peptides. Peptide-induced stabilization of HLA-E expression was measured flow cytometrically after incubating HLA-E-transfected cells with peptides. NK cell function was studied with a (51)chromium-release-assay. Intrahepatic HLA-E expression was analyzed by an indirect immunoperoxidase technique and flow cytometry of isolated cells using a HLA-E-specific antibody. We identified peptide aa35-44, a well-characterized HLA-A2 restricted T cell epitope, as a peptide stabilizing HLA-E expression and thereby inhibiting NK cell-mediated lysis. Blocking experiments confirmed that this inhibitory effect of peptide aa35-44 on natural cytotoxicity was mediated via interactions between CD94/NKG2A receptors and enhanced HLA-E expression. In line with these in vitro data we found enhanced intrahepatic HLA-E expression on antigen-presenting cells in HCV-infected patients. Our data indicate the existence of T cell epitopes that can be recognized by HLA-A2 and HLA-E. This dual recognition may contribute to viral persistence in hepatitis C.

Acute hepatitis B progresses to liver failure with the need of liver transplantation in about 1% of cases. We treated patients with severe acute or fulminant hepatitis B with lamivudine in an attempt to prevent hepatitis B virus (HBV) reinfection after potential liver transplantation. Since September 2000, 17 patients with severe acute or fulminant HBV infection were treated with 100 or 150 mg lamivudine daily once we had evidence for a severe course as indicated by an INR >2.0. These were compared to a historic control from our unit and to external patients. Fourteen of the 17 patients (82.4%) survived with full recovery without liver transplantation. All these 14 individuals cleared HBsAg on lamivudine within less than 6 months. Twelve patients recovered quickly as indicated by a normalized prothrombin time within 1 week while two patients had a more prolonged course. None of the patients showed an adverse event. Three patients requiring transplantation despite lamivudine therapy had more advanced disease on admission, of whom one had additionally ingested paracetamol (acetaminophen) while the second was already HBV-DNA negative by polymerase chain reaction on admission. The lamivudine treated patients had significant higher frequency of survival without liver transplantation 82.4 vs 20% (4/20) in the historic control (P < 0.001). Similar data were derived from external centres using lamivudine (15/20, 75%). Lamivudine is safe in patients with severe acute or fulminant hepatitis B, leading to fast recovery with the potential to prevent liver failure and liver transplantation when administered early enough.

The contribution of the acute phase inducer interleukin 6 (IL-6) in the pathogenesis of liver diseases is yet unclear. Our analysis showed enhanced expression of IL-6 in livers derived from patients with acute and chronic liver diseases. Additionally, IL-6 plasma levels were significantly increased in patients with chronic liver diseases and showed an inverse correlation with biochemical markers of liver function and a positive correlation with inflammatory markers, signs of portal hypertension, and the degree of liver fibrosis. To prove the relevance of these clinical findings, we applied the tetrachlorcarbonide (CCl 4 ) model to conditional knockout animals (Cre/loxP system) for gp130, the common signal transducer of IL-6 family cytokines. Cre recombinases were expressed through a hepatocyte (AlfpCre) and a ubiquitous (MxCre) control element. Gp130 deleted mice had a totally abolished STAT3 activation and acute phase response induction, but gp130 deletion had no effect on the degree of acute liver injury and subsequent hepatocyte proliferation. In contrast, during chronic liver injury induced by biweekly application of CCl 4 , deletion of the gp130 receptor in nonparenchymal liver cells and not hepatocytes resulted in fibrosis progression. In conclusion, our experiments indicate an involvement of IL-6 in the pathogenesis of liver diseases and suggest a protective role of IL-6/gp130-dependent pathways in nonparenchymal liver cells during fibrosis progression in chronic liver diseases. (HEPATOLOGY 2003;38:218-229.)

Background: Diverticular disease is one of the most common disorders of the gastrointestinal tract. 28-45% of the population develop colonic diverticula, while about 25% suffer symptoms and about 5% complications. Aim: To create formal guidelines for diagnosis and management. Methods: Six working groups with 44 participants analyzed key questions in subject areas assigned to them. Following a systematic literature search, 451 publications were included. Consensus was obtained by agreement within the working groups, two Delphi processes and a guideline conference. Results: Targeted management of diverticular disease requires a classificatory diagnosis. A new classification was created. In addition to the clinical examination, intestinal ultrasound or computed tomography is the determining factor. Interval colonoscopy is recommended to exclude comorbidities. A low-fiber diet, obesity, lack of exercise, smoking and immunosuppression have an adverse impact on diverticulosis. This can lead to diverticulitis. Antibiotics are no longer recommended in uncomplicated diverticulitis if no risk factors such as immunosuppression are present. If close monitoring is ensured, uncomplicated diverticulitis can be treated on an outpatient basis. Complicated diverticulitis should be treated in hospital, involving broad-spectrum antibiotic therapy, where necessary abscess drainage, and surgery, if possible laparoscopically. In the case of chronic relapsing diverticulitis, the risk of perforation decreases with each episode, so that surgery is no longer recommended after the second episode but only following individual assessment. Conclusions: New findings on diverticular disease call into question the overuse of antibiotics and excessive indications for surgery. Targeted treatment requires a precise diagnosis and intensive interdisciplinary cooperation. i 2014 S. Karger AG, Basel