Epstein-Barr virus (EBV) isEpstein-Barr virus (EBV) is a human herpesvirus that is estimated to infect up to 90% of the world's population (28,29). EBV infection is associated with several human diseases, including infectious mononucleosis, nasopharyngeal carcinoma, Burkitt's lymphoma, and, in immunosuppressed patients, B-cell and T-cell lymphomas (28,29). Thus, EBV is a serious pathogen and poses a significant threat to human health.Like other herpesviruses, primary infection with EBV is followed by a persistent infection of the human host. Oropharyngeal epithelium is thought to be the primary site of EBV infection and replication and of viral spread (28-30, 51), while B cells are the major site of persistent latency (28-31). Eleven of EBV's approximately 100 viral genes are expressed during latency. These include ones encoding the EBV-encoded nuclear antigens (EBNAs 1 to 6), the latent membrane proteins (LMPs 1 and 2), two EBV-encoded small nuclear RNAs, and the BamHIA transcripts (28, 29). Expression of a subset of the latter genes is sufficient to immortalize B cells and to maintain steady-state levels of the viral genome (31). Treatment of certain latently infected B-cell populations with reagents such as phorbol esters (5, 17, 64), Ca 2ϩ ionophores (15), sodium butyrate (26, 38), and serum factors (2) or cross-linking of surface anti-immunoglobulin (12, 21, 50, 53) leads to cellular differentiation and the concomitant induction of the rest of EBV's genes, followed by viral genome replication to higher copy number and production of infectious virus particles (28-30).Two immediate-early genes, BZLF1 and BRLF1, are the first to be expressed during induction of EBV out of latency (11,23,32,52). The protein products of both of these genes are strong transcriptional transactivators (9, 16). The product of the BZLF1 gene, referred to as Zta, ZEBRA, or EB1, plays a crucial role in the disruption of latency and initiation of the viral infectious cycle (10,11,41,46,52). Thus, regulation of Zta expression is critical to the state of EBV in cells.The transcriptional regulation of the BZLF1 promoter (also referred to as Zp) has been studied extensively. Zp exhibits very low basal activity and is readily activated by inducers of the viral infectious cycle. The cis-acting elements necessary both for basal activity and for response to exogenous inducers lie within the nucleotide (nt) Ϫ221 to ϩ12 region of the promoter relative to the transcriptional initiation site (12,17,18). These elements have been divided into three classes ( Fig. 1; also, see reference 36 and references therein). Four AT-rich elements, termed ZIA to ZID, are dispersed throughout the promoter. They can bind the transcription factors Sp1 and Sp3 (34) and myocyte enhancer factor 2D (37, 44). A second type of element, ZII, shares significant homology with the consensus CRE/AP-1 binding site (1,13,25,54). Finally, a region called ZIII contains multiple binding sites for the Zta protein itself (18). It has been proposed that activation of the BZLF1 gene oc...

BackgroundOur Thyroid-Multidisciplinary Clinic is a large referral site for thyroid diseases. Thyroid biopsies are mainly performed for thyroid cancer screening. Yet, Hashimoto thyroiditis (HT) is being too frequently diagnosed. The prevalence of HT is reported as 0.3-1.2% or twice the prevalence of type 1 diabetes. However, the prevalence of HT confirmed by cytology is still uncertain. To evaluate different aspects of thyroid physiopathology including prevalence of Hashimoto's, a database of clinical features, ultrasound images and cytology results of patients referred for FNA of thyroid nodules was prospectively developed.MethodsWe retrospectively studied 811 consecutive patients for whom ultrasound guided thyroid FNA biopsies were performed at our clinic over 2.5 year period (Mar/2006-Sep/2008).ResultsThe analysis of our database revealed that from 761 patients, 102 (13.4%) had HT, from whom 56 (7.4%) were euthyroid or had sub-clinical (non-hypothyroid) disease, and 46 (6%) were clinically hypothyroid.ConclusionsThis is the first study to show such a high prevalence of HT diagnosed by ultrasound-guided FNA. More strikingly, the prevalence of euthyroid HT, appears to be >5% similar to that of type 2 diabetes. Based on our results, there might be a need to follow up on cytological Hashimoto's to monitor for thyroid failure, especially in high risk states, like pregnancy. The potential risk for thyroid cancer in patients with biopsy-proven inflammation of thyroid epithelium remains to be established prospectively. However, it may explain the increased risk for thyroid cancer observed in patients with elevated but within normal TSH.

SummaryNumerous cases of primary hypophysitis have been described over the past 25 years with, however, little insight into the cause(s) of this disease. In order to guide treatment, a better understanding of the pathogenesis is needed. We studied the pathogenesis of primary hypophysitis by analysing systematically the immune response at the pituitary tissue level of consecutive cases of 'lymphocytic' hypophysitis who underwent pituitary biopsy. In order to investigate further the pathogenesis of their diseases we characterized two cases at clinical, cellular and molecular levels. We show here, for the first time, that lymphocytic hypophysitis probably encompasses at least two separate entities. One entity, in agreement with the classical description of lymphocytic hypophysitis, demonstrates an autoimmune process with T helper 17 cell dominance and lack of T regulatory cells. The other entity represents a process in which T regulatory cells seem to control the immune response, which may not be self-but foreign-targeted. Our data suggest that it may be necessary to biopsy suspected primary hypophysitis and to analyse pituitary tissue with immune markers to guide treatment. Based on our results, hypophysitis driven by an immune homeostatic process should not be treated with immunosuppression, while autoimmune-defined hypophysitis may benefit from it. We show here for the first time two different pathogenic processes classified under one disease type and how to distinguish them. Because of our findings, changes in current diagnostic and therapeutic approaches may need to be considered.

Objectives The present study was conducted to evaluate the expression and function of AP-2α isoforms in pancreatic ductal adenocarcinoma. Methods AP-2α expression was evaluated at RNA level by reverse transcription-polymerase chain reaction and at the protein level by western blotting and immunofluorescence. Its function as a transcription factor was evaluated in transient transfection experiments: DNA binding properties by electromobility shift assay and transactivation capabilities by Luciferase assay. Results Multiple alternative splicing events of AP-2α messenger occurred in all human pancreatic cancer cell lines, including a novel isoform, termed variant 6, which was not present in HeLa cells. At the protein level, except for one cell line, all pancreatic cancer cell lines expressed high nuclear levels of AP-2α. We also showed that AP-2α expressed by the pancreatic cancer cell lines could bind its cognate recognition site and activate transcription. However, variant 6 while not able to activate transcription did not act in a dominant negative manner when co-transfected with the full length protein. Conclusions Multiple isoforms of AP-2α are highly expressed in pancreatic cancer cell lines including a new isoform, AP-2α variant 6, which appears to be pancreatic cancer specific and is deprived of transcriptional activity.