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Gerald Niedobitek

Publications and source records attributed to Gerald Niedobitek.

At least 19 recordsLinked to original sources
PubMed2006

Expression of Epstein-Barr virus (EBV)-encoded latent membrane proteins and STAT3 activation in nasopharyngeal carcinoma.

The Epstein-Barr virus (EBV) is associated with virtually all cases of undifferentiated nasopharyngeal carcinoma (NPC), and it was proposed that the EBV-encoded transforming protein, latent membrane protein (LMP) 1, may play a role in the neoplastic process. It was proposed recently that LMP1 expression in epithelial cells may be regulated through a loop involving activated signal transducer and activator of transcription 3 (STAT3), LMP1, LMP1-mediated induction of interleukin (IL)-6 expression and STAT3 activation through the IL-6 receptor. This autoregulatory loop may be suppressed by another viral protein, LMP2A, an effect which in turn can be overcome by exogenous IL-6. Here we show that, as expected, expression of LMP1 and LMP2A tend to be exclusive in NPC tumours. Rare cases showing a co-expression of both proteins can be explained by STAT3 activation via the receptors for IL-6 or epidermal growth factor. STAT3 activation was a consistent feature of NPC tumour cells. However, in most cases, this was not accompanied by detectable expression of LMP1, suggesting either that LMP2A expression may suffice to suppress LMP1 expression or that additional factors may be operational. This study emphasises the need to correlate in vitro results with observational studies of ex vivo tumour tissues.

ErbB Receptors↗
PubMed2006

Epstein-Barr virus nuclear antigen 2 inhibits AID expression during EBV-driven B-cell growth.

Somatic hypermutation and class-switch recombination in germinal centers critically depend on activation-induced cytidine deaminase (AID). Deregulation of AID may lead to the aberrant activation or persistence of both genetic processes, thus contributing to the pathogenesis of B-cell lymphomas by mistargeted mutagenesis or recombination. The Epstein-Barr virus (EBV) establishes an asymptomatic latent infection in more than 90% of the human population, but it has also been linked to lymphomagenesis. A cooperative relationship of EBV and the germinal center reaction during the establishment of viral persistence has been postulated, but the contribution of EBV latent genes to the respective genetic events remains to be investigated in detail. In the present study, we show that activation of the EBV growth program has a clear inhibitory effect on AID expression, due to a negative effect of the master transcription factor of this program, EBNA2. This mechanism may counterbalance AID induction by the LMP1 protein, in order to prevent deleterious genetic changes during EBV-induced B-cell growth. EBNA2-mediated AID inhibition also provides a molecular explanation for the previously observed differences in somatic hypermutation activity in EBV-associated lymphoproliferative diseases, thus pointing to a crucial mechanism of EBV-mediated regulation of genomic integrity.

B-Lymphocytes↗
PubMed2006

Tumor-infiltrating cytotoxic T cells but not regulatory T cells predict outcome in anal squamous cell carcinoma.

PURPOSE: Tumor-infiltrating lymphocytes (TIL) are a possible prognostic factor in solid tumors. Cytotoxic TILs are generally considered as prognostically favorable, whereas regulatory T cells (Treg) may have adverse effects by virtue of their ability to inhibit effector cells. We have evaluated the effect of T-cell subsets on survival in patients with anal squamous cell carcinoma following radiochemotherapy. METHODS: Biopsy specimens from 38 patients with anal carcinomas were evaluated using tissue microarrays and immunohistochemistry for the presence of tumor-infiltrating immune cells using CD3, CD4, CD8, and CD68 antibodies. Treg were identified using an antibody directed against the transcription factor FoxP3, and granzyme B served as a marker for cytotoxic cells. Intratumoral immune cells were enumerated using a semiautomatic image analysis program. Prognostic effect of TIL subsets was evaluated by the log-rank test comparing no evidence of disease survival for groups with high and low numbers using median values as cutoff. RESULTS: CD3+ and CD4+ TILs influenced no evidence of disease survival: 3-year rates for patients with low numbers were 89% and 95%, respectively, and 54% (P = 0.02) and 48%, (P = 0.01), respectively, in cases with high numbers. Large numbers of tumor-infiltrating granzyme B+ cytotoxic cells had a significant negative prognostic effect (P = 0.008), whereas no effect was observed for Treg. CONCLUSIONS: TILs were identified as negative prognostic indicators in anal squamous cell carcinomas with granzyme B+ cytotoxic cells showing highest effect on outcome. This is possibly explained by the selection of therapy-resistant tumor cell clones. No prognostic influence of Treg was found. Knowledge of local immune responses is important for the development of immunotherapeutic strategies.

Anus Neoplasms↗
PubMed2006

Sporadic EBV-associated lymphoepithelial salivary gland carcinoma with EBV-positive low-grade myoepithelial component.

Salivary gland lymphoepithelial carcinomas (LECs) are associated with Epstein-Barr virus (EBV) in endemic areas, whereas sporadic cases are usually EBV negative. We have studied two EBV-associated LECs from Caucasian patients for their EBV gene expression profile and their immunophenotype. Tumour cells of case 1 showed expression of EBNA1 only, corresponding to an EBV latency type I. Tumour cells of this case expressed various basal and glandular cytokeratins. In case 2, the LEC was accompanied by a low-grade spindle cell lesion with an immunophenotype of myoepithelial cells, whereas the high-grade tumour expressed cytokeratin (Ck) 8 only. In case 2, the high-grade tumour showed an EBV lantency II pattern with expression of EBNA1, LMP1 and LMP2A (latency II). The spindle cell lesion of this case was also EBV-infected and showed low levels of EBNA1 and LMP1 expression, while LMP2A was not detectable. The detection of EBV in both components of case 2 together with immunophenotypic evidence of transition between both components supports the notion that at least some LECs arise through a low-grade myoepithelial intermediate. Expression of LMP2A may be of therapeutic interest because it may make such cases amenable to immunotherapy with EBV-specific cytotoxic T cells.

Carcinoma, Squamous Cell↗
PubMed2006

Primary cutaneous follicle center lymphoma and primary cutaneous large B-cell lymphoma, leg type, are both targeted by aberrant somatic hypermutation but demonstrate differential expression of AID.

We assessed primary cutaneous large B-cell lymphoma, leg type (PCLBCL, leg type; n = 13), and primary cutaneous follicle center lymphoma (PCFCL; n = 19) for somatic hypermutation (SHM) of BCL6, and aberrant SHM of MYC, RhoH/TTF, and PAX5. We demonstrate SHM of BCL6 in 8 PCLBCLs (62%), leg type, and 7 PCFCL patients (37%), and aberrant SHM in PAX5, RhoH/TTF, and/or MYC in 7 PCLBCLs (54%), leg type, and 10 PCFCL patients (53%). The majority of mutations consisted of single base-pair substitutions (n = 54) with rare deletions/insertions (n = 4), and displayed molecular features typical of the SHM process. Quantitative real-time PCR and immunohistochemical stainings for activation-induced cytidine deaminase, which is indispensable for SHM, demonstrated significantly higher expression in PCLBCL, leg type. Our results suggest that (aberrant) SHM may contribute to the pathogenesis of PCLBCL, leg type, and PCFCL and is not restricted to diffuse large B-cell lymphomas with an aggressive clinical behavior.

Cytidine Deaminase↗
PubMed2006

Nuclear and cytoplasmic AID in extrafollicular and germinal center B cells.

Activation-induced cytidine deaminase (AID) is necessary for immunoglobulin somatic hypermutation (SHM) and class switch recombination (CSR) in T-dependent immune response in germinal centers (GCs). The structural similarity of AID with RNA-editing enzymes and its largely cytoplasmic location have fueled controversial views of its mode of interaction with DNA. We show that AID, a mature B-cell-restricted cytoplasmic antigen, is relocated into the nucleus in 2.5% of CDKN1B(-), CCNB1(-) GC cells. The GC dark zone and the outer zone (OZ), but not the light zone, contain nuclear and cytoplasmic AID(+) blasts. AID(+) cells in the OZ are in contact with T cells and CD23(-) follicular dendritic cells. In addition, AID is expressed in extrafollicular large proliferating B cells, 14% of which have nuclear AID. GC and extrafollicular AID(+) cells express E47 but not the inhibiting BHLH protein Id2. Outside the GC, AID(+) B cells are in contact with T cells and show partial evidence of CD40 plus bcr stimulation-dependent signature (CCL22, JunB, cMYC, CD30) but lack early and late plasma cell markers. The distribution of nuclear AID is consistent with the topography of SHM and CSR inside the GC and in extrafollicular activated B cells.

Animals↗
PubMed2006

A humanized HLA-DR antibody (hu1D10, apolizumab) in combination with granulocyte colony-stimulating factor (filgrastim) for the treatment of non-Hodgkin's lymphoma: a pilot study.

Apolizumab is a humanized monoclonal antibody against a polymorphic epitope on HLA DRbeta that demonstrated evidence for therapeutic activity in follicular lymphoma patients. In pre-clinical studies, we previously reported that granulocyte colony-stimulating factor (G-CSF) treatment significantly enhanced lymphoma cell killing by HLA class II antibodies, including apolizumab. These results suggested a combination trial of apolizumab and G-CSF (filgrastim). In this trial, we treated six patients with relapsed or refractory 1D10-positive non-Hodgkin's lymphoma with filgrastim and variable doses of apolizumab ranging from 0.15 to 1.5 mg/m2. The combination was clinically well tolerated, with only two patients experiencing grade III/IV hematological toxicity (thrombocytopenia and autoimmune hemolytic anemia). Another patient developed a pruritic skin rash, which was probably a treatment-related grade II skin toxicity. Interestingly, two patients with follicular lymphoma who received intensified apolizumab treatment on a three times weekly schedule experienced prolonged stabilization of their disease for 12 and more than 36 months. In conclusion, this small pilot study suggests that a combination of HLA class II antibodies and G-CSF is clinically feasible.

Aged↗
PubMed2006

In situ detection of Epstein-Barr virus and phenotype determination of EBV-infected cells.

Epstein-Barr virus (EBV) establishes a lifelong infection of B cells. Consequently, EBV-carrying B cells are present in the peripheral blood as well as in lymphoid and nonlymphoid tissues of most individuals. As a result, the detection by polymerase chain reaction of EBV genomes in DNA extracts from tumor tissues does not permit conclusions as to the precise cellular source of the virus. For a meaningful analysis of EBV infection, it often is necessary to determine the cellular location of the virus using morphology-based techniques. In situ hybridization for the detection of the small EBV-encoded RNAs (EBERs) has become the standard method for the detection of latent EBV infection. Owing to their abundance, the EBERs represent ideal targets for in situ hybridization using radiolabeled or nonradioactive probes. EBV has been detected in tumors of various lineages, and proliferation of nonneoplastic B cells may occur in the background of EBV-negative tumors. Thus, the assignment of EBV infection to a specific cell type may require double labeling techniques for the simultaneous detection of the virus and of cell lineage-specific gene products. Because of the heterogeneous composition of many EBV-associated tumors, gene expression analysis of EBV-infected cells in tissue sections also may require double labeling techniques. Here, methods are described for the in situ detection and phenotypic characterization of EBV-infected cells in the authors' laboratories.

B-Lymphocytes↗
PubMed2006

Identification of rare Epstein-Barr virus infected memory B cells and plasma cells in non-monomorphic post-transplant lymphoproliferative disorders and the signature of viral signaling.

BACKGROUND AND OBJECTIVES: In early and polymorphic post-transplant lymphoproliferative disorders (PTLD) Epstein-Barr virus (EBV), through its latency proteins, drives the proliferation of B lymphocytes, a process which in immunocompetent individuals leads to the establishment of latently infected memory B cells. DESIGN AND METHODS: We analyzed 11 cases, which included early and polymorphic PTLD, and 12 controls for latency of EBV infection and their antigenic profile. RESULTS: We identified a minority of terminally differentiated EBER+ IRTA1+ memory B cells and EBER+ CD138+ PRDM1+ plasma cells in these samples. These elements were identified both in PTLD and in tumor-free tonsils from post-transplant patients but not in EBV- control tonsils. The expression of EBV latency proteins is heterogeneous, and is associated with activation of the NF-kB pathway. EBV signaling (through EBNA2, LMP1 and LMP2A) and NF-kB activation correlated with upregulation of target proteins: cMYC, JunB, CCL22, TRAF1 and IRF4. EBV-infected lymphocytes in early and polymorphic PTLDs represent a mixture of latencies II, III and, in at least 1/3 of infected cells, of latency 0. INTERPRETATION AND CONCLUSIONS: EBV infection correlates with NF-kB activation, with EBV-dependent cell signaling, and lastly, with the presence of EBV-infected plasma cells and memory cells.

Adolescent↗
PubMed2005

Visualization of a large ventricular aneurysm in a young man by 16-slice multi-detector row spiral computed tomography before successful surgical treatment.

Left ventricular (LV) aneurysm after myocardial infarction without any clinical symptoms is a rare complication of coronary artery disease. In most cases, especially in young people, this complication is diagnosed too late, after rupture into the pericardial cavity has occurred. Here we present the successful surgical repair of a large LV aneurysm in a 35-year-old man. We could visualize this aneurysm and the coronary arteries non-invasively by contrast-enhanced 16-slice multi-detector row spiral computed tomography (MDCT).

Adult↗
PubMed2005

Expression of the interferon-inducible chemokine IP-10 (CXCL10), a chemokine with proposed anti-neoplastic functions, in Hodgkin lymphoma and nasopharyngeal carcinoma.

Hodgkin lymphoma (HL) and nasopharyngeal carcinoma (NPC) are characterized by their association with Epstein-Barr virus (EBV) and an abundant infiltrate of reactive lymphoid cells. The presence of this lymphoid stroma may influence the effect of anti-viral immunotherapy. The interferon-inducible chemokine IP-10 has anti-neoplastic effects in several model systems mediated by T-cells expressing the CXCR3 chemokine receptor. Using in situ hybridization, it is shown that IP-10 is expressed in neoplastic cells of HL and correlates both with the mixed cellularity histotype and with EBV infection. IP-10 expression was also detected in tumour cells of most NPCs as well as in EBV-negative squamous cell carcinomas of the tongue. Thus, in carcinomas, IP-10 expression showed no correlation with EBV infection. Numerous CXCR3-positive lymphocytes were detected in the lymphoid stroma of HL and NPC, raising the possibility of a Th1-predominant immune response in these cases. In view of the proposed anti-neoplastic functions of IP-10 and CXCR3-positive lymphocytes, these findings are unexpected and raise the possibility that endogenous IP-10 expression in the context of human tumours may not exert the anti-tumour effects ascribed to it by in vitro experiments.

Animals↗
PubMed2005

Differential expression of activation-induced cytidine deaminase (AID) in nodular lymphocyte-predominant and classical Hodgkin lymphoma.

Activation-induced cytidine deaminase (AID) is indispensable for class switch recombination and somatic hypermutation of immunoglobulin genes. Expression of AID has been detected in germinal centre centroblasts and in lymphomas derived from germinal centre cells. However, in situ studies of AID expression have until now been hampered by a lack of antibodies suitable for immunohistochemistry. To overcome this problem, an AID-specific monoclonal antibody suitable for immunohistochemical staining of formalin-fixed, paraffin wax-embedded tissue sections has been generated. This antibody was shown to detect AID expression in normal germinal centre B-cells as well as in non-Hodgkin lymphomas with a putative germinal centre origin. Using this antibody, a virtually exclusive cytoplasmic localization of AID in normal and neoplastic B-cells is shown. Employing a combination of immunohistochemistry and AID-specific in situ hybridization, it is demonstrated that AID is consistently expressed in the neoplastic cells of nodular lymphocyte-predominant Hodgkin lymphoma (HLnlp) but only infrequently in classical HL (cHL). This is in keeping with the notion that tumour cells of HLnlp represent transformed germinal centre B-cells showing evidence of somatic hypermutation. AID represents an additional marker useful in the differential diagnosis of HLnlp and cHL.

Antibodies, Monoclonal↗
PubMed2005

Absence of immunoglobulin class switch in primary lymphomas of the central nervous system.

Primary lymphomas of the central nervous system (PCNSLs) were investigated for their capacity to perform further maturation steps. We studied a series of 11 PCNSLs derived from immunocompetent patients for immunoglobulin (Ig) class switch recombination (CSR) by performing reverse transcriptase-polymerase chain reaction (RT-PCR) for transcripts of Ig constant region gene segments (IGHC). This analysis revealed exclusive transcription of IgM and IgD mRNA in the absence of IgG, IgA, or IgE transcription. This finding was corroborated at the protein level by the immunohistochemical demonstration of IgM on the surface of the tumor cells. The unexpected lack of CSR may be due to internal switch mu region deletions, which were detected in 7 of 11 cases. We also found that expression of activation-induced cytidine deaminase (AID), which is required for CSR and somatic hypermutation, was detectable by RT-PCR in 4 of 10 cases and by immunohistochemistry in one of three cases analyzed. This may indicate that ongoing somatic mutation, which is often observed in PCNSL, could be due to sustained AID expression in a fraction of cases and that intraclonal V gene diversity may occur in other cases at an earlier phase of tumor clone expansion, when AID may have been expressed.

Adult↗
PubMed2004

Epstein-Barr virus (EBV) infection in epithelial cells in vivo: rare detection of EBV replication in tongue mucosa but not in salivary glands.

Epstein-Barr virus (EBV) is transmitted through saliva, but the cellular source is controversial. Putative reservoirs include oral epithelium and salivary glands. Tongue mucosal samples, salivary glands, and tongue carcinomas were studied, by immunohistochemistry and in situ hybridization, for evidence of EBV infection. EBV replication was seen in 1.3% of tongue mucosal samples. No latent infection was found at this site. EBV infection was detected neither in normal salivary glands nor in tongue carcinomas. Thus, EBV replication occurs infrequently in tongue epithelial cells, and salivary glands are unlikely to harbor EBV. EBV is unlikely to be involved in the pathogenesis of tongue cancer.

Adult↗
PubMed2004

Expression of tumor necrosis factor receptor-associated factor 1 in nasopharyngeal carcinoma: possible upregulation by Epstein-Barr virus latent membrane protein 1.

EBV infection is associated with virtually all cases of undifferentiated NPC, and the EBV-encoded LMP1 is expressed in a proportion of cases. LMP1 has transforming functions similar to members of the TNF receptor family and activates intracellular signaling cascades through interaction with TRAFs. In B cells, expression of TRAF1 is in turn upregulated by LMP1. LMP1 signaling in epithelial cells may be affected by the presence or absence of TRAF1. By immunohistochemistry, we detected TRAF1 expression in 17 of 42 (40%) EBV+ undifferentiated NPCs. All 7 LMP1+ NPC biopsies were also TRAF1+. Using an RNAse protection assay, high-level TRAF1 expression was detected in an LMP1-expressing NPC-derived cell line (C15) and expression was weaker in 2 LMP1- cell lines (C17, C19). Finally, LMP1 upregulated TRAF1 expression in an EBV- keratinocyte cell line. Our results demonstrate that TRAF1 is expressed in NPC tumor cells in vivo and suggest that TRAF1 expression may be upregulated by LMP1 in NPC. An antiapoptotic function has been proposed for TRAF1, and this may be relevant for the pathogenesis of NPC.

Antigens, Viral↗
PubMed2004

Epstein-Barr virus (EBV) infection and expression of the interleukin-12 family member EBV-induced gene 3 (EBI3) in chronic inflammatory bowel disease.

Herpesviruses have been suggested as possible etiological agents of ulcerative colitis and Crohn's disease. Recently, increased numbers of Epstein-Barr virus (EBV)-infected cells have been detected in ulcerative colitis as compared to Crohn's disease. Interestingly, expression levels of the EBV-induced gene 3 (EBI3), a molecule belonging to the interleukin (IL)-12 family, have also been reported to be elevated in ulcerative colitis as compared to Crohn's disease. To test the hypothesis that these observations might be interrelated, ileocolic resection specimens were examined from 16 patients with ulcerative colitis and from 20 patients with Crohn's disease. The presence of EBV-infected cells and of EBI3-expressing cells was determined quantitatively by in situ hybridisation and immunohistochemistry, respectively. Larger number of EBV-infected cells were seen in areas of active inflammation of ulcerative colitis and Crohn's disease as compared to areas of inactive inflammation. However, there was no statistically significant difference between ulcerative colitis and Crohn's disease. Numbers of EBI3-expressing cells were increased in areas of active inflammation of ulcerative colitis and Crohn's disease but again there was no statistically significant difference between the two diseases. Double labelling experiments showed that EBI3 expression occurred only in a small minority of EBV-infected cells in ulcerative colitis and Crohn's disease. These results suggest that increased numbers of EBV-infected cells in areas of active inflammatory bowel disease (IBD) are secondary to influx or local proliferation of inflammatory cells and do not contribute significantly to local production of EBI3. Assessment of the possible role of EBI3 of the pathogenesis of ulcerative colitis or Crohn's disease requires information regarding the expression of other IL-12 family members.

Adult↗