[A 40-year-old female patient with seronegative autoimmune hepatitis following a newly acquired hepatitis B infection]. / 40-jährige Patientin mit einer seronegativen Autoimmunhepatitis infolge einer Hepatitis-B-Neuinfektion.

We report the case of a 40-year-old female patient admitted at our clinic because of recent onset jaundice and elevated transaminases. Two months before admission the patient had unprotected sexual contact with a potential hepatitis B-infected man. Virological screening performed in our clinic revealed IgM antibodies against hepatitis B virus core protein (anti-HBc-IgM) and elevated HBV-DNA. Our first diagnosis was an acute hepatitis B virus infection. During her stay at our clinic the patient achieved HBe seroconversion and a loss of HBV-DNA. Nevertheless the transaminases remained high and jaundice persisted. The histological examination of the liver biopsy showed interface hepatitis with plasma cells as the characteristic signs of autoimmune hepatitis. On that basis we started an immunosuppressive therapy with prednisolone in parallel with a prophylactic lamivudine therapy and after two weeks there was a complete resolution of jaundice and a normalisation of transaminases. In conclusion, we present a rare case report of an autoimmune hepatitis as a result a newly acquired hepatitis B infection. This case report highlights the relationship between viral infection and autoimmunity within the liver.

Evidence of Notch pathway activation in the ectatic ducts of chronic pancreatitis.

Ductal concretions in chronic pancreatitis (CP) are one of the causes of ductal obstruction, resulting in pancreatic ductal hypertension (PDH) and duct ectasia. Ductal epithelium subjected to chronic stress by PDH may undergo molecular alterations, thereby not only initiating and sustaining the inflammatory process but also activating molecules that have transforming potential. Acino-ductal metaplasia and pancreatic intraepithelial neoplasia (PanIN) are frequently seen in CP. Using laser capture microdissection, cDNA microarrays and Ingenuity Pathways Analysis, we found an altered Notch pathway in the ectatic ducts of CP. The microarray data was further validated by real-time PCR. We also found elevated transcripts of Notch receptors, Notch1 and Notch3 in microdissected ectatic ducts of CP. The Notch pathway ligands, Jagged/Delta-like and a Notch target, HES-related repressor protein (HERP), were up-regulated in ectatic compared to normal pancreatic ducts, while another target of Notch, hairy/enhancer of split (HES), was down-regulated. The transcripts of Delta-like1 and Jagged1 were increased 3.7-fold and 1.3-fold, respectively, while those of HERP1 were elevated 2.4-fold in the ectatic ducts of CP, compared to normal ducts. Immunohistochemistry showed that Jagged1 was not expressed in normal pancreatic ducts, while it was highly expressed in ectatic ducts. This pattern of Notch component alteration in ectatic ducts was mimicked to some extent in vitro in a human pancreatic duct epithelial (HPDE) cell line, when subjected to a pressure of 200 mmHg for 24 h. Therefore, we conclude that in the ectatic ducts of CP, PDH activates signalling pathways such as Notch, which have transforming potential.

Sex-specific telomere length profiles and age-dependent erosion dynamics of individual chromosome arms in humans.

During aging, telomeres are gradually shortened, eventually leading to cellular senescence. By T/C-FISH (telomere/centromere-FISH), we investigated human telomere length differences on single chromosome arms of 205 individuals in different age groups and sexes. For all chromosome arms, we found a linear correlation between telomere length and donor age. Generally, males had shorter telomeres and higher attrition rates. Every chromosome arm had its individual age-specific telomere length and erosion pattern, resulting in an unexpected heterogeneity in chromosome-specific regression lines. This differential erosion pattern, however, does not seem to be accidental, since we found a correlation between average telomere length of single chromosome arms in newborns and their annual attrition rate. Apart from the above-mentioned sex-specific discrepancies, chromosome arm-specific telomere lengths were strikingly similar in men and women. This implies a mechanism that arm specifically regulates the telomere length independent of gender, thus leading to interchromosomal telomere variations.

Impaired CD95 expression predisposes for recurrence in curatively resected colon carcinoma: clinical evidence for immunoselection and CD95L mediated control of minimal residual disease.

BACKGROUND: Loss of CD95 expression in tumour cells occurs frequently in colon carcinoma and may be associated with disease progression. On the other hand, neo-expression of CD95L in tumour cells may contribute to immune evasion. AIMS: We aimed at further exploring the functional role and prognostic significance of the CD95/CD95L death inducing system in colon carcinomas. PATIENTS AND METHODS: CD95 and CD95L expression was examined by immunohistochemistry in 128 R0 resected UICC (International Union against Cancer) stage II/III colon carcinomas and correlated with disease free survival. RESULTS: CD95 expression in tumour cells was observed in only 30 carcinomas (23.4%) whereas the others had at least a minor subpopulation of CD95 negative cells. Loss of CD95 in tumour cells was related to adverse prognosis in uni- and multivariate analysis (p = 0.046 and p = 0.036, respectively). Tumour infiltrating lymphocytes (TIL) were the major source of CD95L in colon carcinomas. CD95L+TIL were present in 83% of cases whereas CD95L was found in tumour cells in only 12% of cases. Moreover, a high rate of CD95L+TIL correlated with prolonged disease free survival in patients with UICC stage II (p = 0.05) but not in those with stage III. CONCLUSIONS: Loss of CD95 in tumour cells may be an independent prognostic factor in colon carcinomas. The CD95L counterattack is not a relevant feature in colon carcinoma but CD95L+TIL may contribute to tumour control in the early stages of the disease, exerting a concurrent selection pressure in the direction of CD95 abrogation/resistance.

[Biallelic mutation of SOCS-1 impairs JAK2 degradation and sustains phospho-JAK2 action in MedB-1 mediastinal lymphoma line]. / Die biallelische Mutation von SOCS-1 verhindert den Abbau von JAK2 und prolongiert die Wirkung von phospho-JAK2 in der mediastinalen B-Zell Lymphomlinie MedB-1.

Primary mediastinal B-cell lymphoma (PMBL) is a well-defined subtype of diffuse large B-cell lymphoma. Molecular cytogenetics revealed frequent gains of 9 p24. JAK2, mapping in this region, is presently regarded as a candidate oncogene since expression profiling showed high JAK2 transcript levels and JAK2 was found to be constitutively phosphorylated in mediastinal B-cell lymphomas. We confirm that in the MedB-1 mediastinal B-cell line, harbouring a trisomy 9, JAK2 transcription is elevated and the product is highly phosphorylated. However, JAK2 is not over-expressed at the protein level. On top, JAK2 protein turnover is even delayed. This unexpected finding coincides with a biallelic mutation of the SOCS-1 gene in this cell, which abrogates SOCS box function of the protein. Ectopic expression of wt-SOCS-1 in MedB-1 leads to growth arrest, dramatic reduction of phospho-JAK2 and its downstream partner phospho-STAT5. We conclude that, in MedB-1, action of phospho-JAK2 is sustained due to defective SOCS-1. Hence, SOCS-1 qualifies as a novel tumor suppressor. Of note, the SOCS-1 mutations are also present in the parental tumor of MedB-1 and were detected in 9 of 20 PMBL.

Sustained hyposmotic stress induces cell death: apoptosis by defeat.

We describe sustained hyposmotic stress as a novel type of environmental condition enforcing apoptosis. In a dose- and time-dependent fashion, hyposmotic stress leads to a delayed type of apoptosis with considerable variations in constitutive sensitivity among different cell types. For example, after 48 h at 84 mosmol/l, the death rate ranged from 10.8 +/- 0.7% in AsPc1 human pancreatic carcinoma cells to 72.0 +/- 1.6% in HK-2 human kidney tubule cells. Caspase inhibitors rendered cells more resistant to hyposmolar stress; the caspase 3 inhibitor Ac-Asp-Glu-Val-aspartic acid aldehyde was the most efficient. After 24 h of stress, HT-29 colon carcinoma and HK-2 cells had increased their mitochondrial mass. This went along with an increase in mitochondrial membrane potential in HT-29 cells but with a decrease in HK-2 cells. Starting at 2 h of stress, we detected transient CD95L transcription followed by surface expression of CD95L in HT-29 but not in HK-2 cells. Inhibitory CD95L antibody partially inhibited specific death in HT-29 but not in HK-2 cells. Thus, as in other types of stress-induced apoptosis, the CD95/CD95L system is one of the different routes to suicide optionally used by hyposmotically stressed cells. Our findings may have clinical implications for the prevention and treatment of tissue damage caused by severe hyposmolar states.

MedB-1, a human tumor cell line derived from a primary mediastinal large B-cell lymphoma.

Primary mediastinal B-cell lymphoma is a locally highly aggressive but poorly disseminating tumor composed of medium sized or large cells most probably of thymic medullary origin. It has a mature B-cell phenotype, typically lacks immunoglobulin expression and has variable defects in expression of HLA-molecules. We present here a cell line, MedB-1, derived from such a tumor. As is frequently found in mediastinal B-cell lymphomas in situ, MedB-1 is CD10(-), CD19(+), CD21(-), CD22(+), CD23(+), CD25(-), CD37(+), CD38(-), CD39(+), CD40(+), CD54(+), CD95(+). Like the parental tumor, MedB-1 lacks HLA-A,B,C alpha-chains and beta(2)microglobulin and expresses HLA-D molecules at decreased levels. Both parental tumor and MedB-1 cells are clonally related as shown by immunoglobulin heavy chain gene rearrangement analysis. Unlike the parental tumor tissue, the MedB-1 cell line cytoplasmically expresses IgG/kappa in a very small subset of cells under standard culture conditions. MedB-1 does not contain any Epstein-Barr virus DNA. In a tissue adhesion assay MedB-1 cells showed an extensive binding to the medullary region of normal thymus. Altogether, MedB-1 is a suitable tool for functional and molecular analysis of this distinct lymphoma entity.

Differential and mutually exclusive expression of CD95 and CD95 ligand in epithelia of normal pancreas and chronic pancreatitis.

Acinar regression in chronic pancreatitis may be due to immune attack in parenchymal areas neoexpressing HLA-DR molecules. CD4+Th1 cytotoxic T cells induce apoptosis of their targets via oligomerizing CD95 (APO-1/Fas) death receptors on target cells by their CD95 ligand (CD95L). We determined the expression of CD95 and CD95L in epithelia of normal and chronically inflamed pancreatic tissues. We applied RT-PCR and Western blotting for CD95L expression profiles, serial frozen section immunohistochemistry to detect CD95, CD95L, and HLA-DR molecules, CD3, CD4, CD11c, and S-100 protein (S100p). Normal pancreases and chronic pancreatitis contain CD95L message and protein. Immunohistochemistry revealed a mutually exclusive expression of CD95 and CD95L. Physiologically, acini were CD95-/CD95L+, ducts were CD95-/CD95L-, and islets were CD95-/CD95L+. In areas of lymphohistiocytic infiltration, mainly consisting of CD3+CD4+ T cells and CD11c+, CD4+/-, S100p+ interstitial dendritic cells, and in areas of initial fibrosis, acini and ducts were HLA-DR+, acini CD95+/CD95L-, and ducts CD95+/CD95L-. Islet cells were CD95-/CD95L+ in both conditions. IFNgamma levels in protein lysates, as measured by an immunoassay, were significantly higher in chronic pancreatitis than in normal pancreas (p < 0.0003). In vitro, IFNgamma down-modulated CD95L message and protein in ASPC1 and BxPc3 pancreatic carcinoma cells. In conclusion, pancreatic epithelia differentially express CD95 and CD95L in a mutually exclusive manner. In chronic pancreatitis the CD95-/CD95L+ status is conserved in islet cells even in the vicinity of lymphohistiocytic infiltrates, whereas it is lost in acini coexpressing HLA-DR. As a potential consequence, and possibly triggered by local release of IFNgamma, CD4-Th1 cells may cognately interact with and successfully attack exocrine cells by triggering CD95 on their target without being killed by epithelial, CD95L-mediated, counterattack.

CD95 ligand (CD95L) immunohistochemistry: a critical study on 12 antibodies.

In recent years, some studies on the expression of CD95(Fas/APO-1) ligand (CD95L) in tissues or cells raised concerns about the specificity of the antibodies used. We therefore tested 12 CD95L antibodies for their reliability in immunocyto/histochemistry by (i) staining CD95L-transfected and control CV-1/EBNA cells and (ii) comparing staining patterns in immunohistochemically labeled tissue sections with the localization of CD95L+ cells in in situ hybridization. While G247-4, NOK-1, NOK-2, 4H9, and MIKE-1 stained CD95L-transfected cells and did not significantly bind to controls, G247-4 was the only antibody giving satisfying signals in tissue sections perfectly matching the distribution of CD95L+ cells by in situ hybridization. MAb 33, C-20, and N-20 comparably stained both transfected and control cells and showed considerable background or falsely positive staining in sections. MIKE-2, 8B8, A11, and 4A5 did not or only very faintly bind to either cells and, thus, were not tested on sections. We conclude that G247-4 is the only tested antibody that is recommendable for immunohistochemistry.