Project description:The main target cells for Epstein-Barr virus (EBV) infection and persistence are B lymphocytes, although T and NK cells can also become infected. In this paper, we characterize the EBV present in 21 pediatric and adult patients who were treated in France for a range of diseases that involve infection of T or NK cells. Of these 21 cases, 5 pediatric patients (21%) and 11 adult patients (52%) were of Caucasian origin. In about 30% of the cases, some of the EBV genomes contain a large deletion. The deletions are different in every patient but tend to cluster near the BART region of the viral genome. Detailed investigation of a family in which several members have persistent T or NK cell infection by EBV indicates that the virus genome deletions arise or are selected independently in each individual patient. Genome sequence polymorphisms in the EBV in these T or NK cell diseases reflect the geographic origin of the patient and not a distinct type of EBV (the 21 cases studied included examples of both type 1 and type 2 EBV infection). Using virus produced from type 1 or type 2 EBV genomes cloned in bacterial artificial chromosome (BAC) vectors, we demonstrate infection of T cells in cord blood from healthy donors. Our results are consistent with transient infection of some T cells being part of normal asymptomatic infection by EBV in young children. IMPORTANCE EBV contributes to several types of human cancer. Some cancers and nonmalignant lymphoproliferative diseases involving T or NK cells contain EBV. These diseases are relatively frequent in Japan and China and have been shown sometimes to have deletions in the EBV genome in the disease cells. We identify further examples of deletions within the EBV genome associated with T or NK cell diseases, and we provide evidence that the virus genomes with these deletions are most likely selected in the individual cases, rather than being transmitted between people during infection. We demonstrate EBV infection of cord blood T cells by highly characterized, cloned EBV genomes and suggest that transient infection of T cells may be part of normal asymptomatic infection by EBV in young children.
Project description:Epstein-Barr virus (EBV), originally discovered through its association with Burkitt lymphoma, is now aetiologically linked to a remarkably wide range of lymphoproliferative lesions and malignant lymphomas of B-, T- and NK-cell origin. Some occur as rare accidents of virus persistence in the B lymphoid system, while others arise as a result of viral entry into unnatural target cells. The early finding that EBV is a potent B-cell growth transforming agent hinted at a simple oncogenic mechanism by which this virus could promote lymphomagenesis. In reality, the pathogenesis of EBV-associated lymphomas involves a complex interplay between different patterns of viral gene expression and cellular genetic changes. Here we review recent developments in our understanding of EBV-associated lymphomagenesis in both the immunocompetent and immunocompromised host.This article is part of the themed issue 'Human oncogenic viruses'.
Project description:Our appreciation for the extent of Epstein Barr virus (EBV) transcriptome complexity continues to grow through findings of EBV encoded microRNAs, new long non-coding RNAs as well as the more recent discovery of over a hundred new polyadenylated lytic transcripts. Here we report an additional layer to the EBV transcriptome through the identification of a repertoire of latent and lytic viral circular RNAs. Utilizing RNase R-sequencing with cell models representing latency types I, II, and III, we identified EBV encoded circular RNAs expressed from the latency Cp promoter involving backsplicing from the W1 and W2 exons to the C1 exon, from the EBNA BamHI U fragment exon, and from the latency long non-coding RPMS1 locus. In addition, we identified circular RNAs expressed during reactivation including backsplicing from exon 8 to exon 2 of the LMP2 gene and a highly expressed circular RNA derived from intra-exonic backsplicing within the BHLF1 gene. While expression of most of these circular RNAs was found to depend on the EBV transcriptional program utilized and the transcription levels of the associated loci, expression of LMP2 exon 8 to exon 2 circular RNA was found to be cell model specific. Altogether we identified over 30 unique EBV circRNAs candidates and we validated and determined the structural features, expression profiles and nuclear/cytoplasmic distributions of several predominant and notable viral circRNAs. Further, we show that two of the EBV circular RNAs derived from the RPMS1 locus are detected in EBV positive clinical stomach cancer specimens. This study increases the known EBV latency and lytic transcriptome repertoires to include viral circular RNAs and it provides an essential foundation and resource for investigations into the functions and roles of this new class of EBV transcripts in EBV biology and diseases.
Project description:Systemic chronic active Epstein-Barr virus disease (sCAEBV) is a rare and fatal neoplasm, involving clonally proliferating Epstein-Barr virus (EBV)-infected T cells or natural killer cells. Patients with sCAEBV have abnormal titers of anti-EBV antibodies in their peripheral blood, but their significance is unknown. We retrospectively investigated titers and their relationship with the clinical features of sCAEBV using the data collected by the Japanese nationwide survey. Eighty-four patients with sCAEBV were analyzed. The anti-EBV nuclear antigen (EBNA) antibody, targeting EBNA-expressing EBV-positive cells, was found in 87.5% of children (<15 years old), 73.7% of adolescents and young adults (15-39 years old), and 100% of adults (≥40 years old). Anti-EBNA antibody titers were significantly lower and anti-VCA-IgG antibody titers significantly higher in patients with sCAEBV than those in healthy controls (p < 0.0001). Patients with high anti-VCA-IgG and anti-early antigen-IgG antibody (antibodies against the viral particles) levels had significantly better 3-year overall survival rates than those with low titers, suggesting that patients with sCAEBV have a reduced immune response to EBV-infected cells.
Project description:Our appreciation for the extent of Epstein Barr virus (EBV) transcriptome complexity continues to grow through findings of EBV encoded microRNAs, new long non-coding RNAs, and hundreds of new polyadenylated lytic transcripts. Here we report an additional layer to the EBV transcriptome through the identification of a repertoire of latent and lytic viral circRNAs. Utilizing RNase R-sequencing with cell models representing latency types I, II, and III, we identified circRNAs expressed from the latency Cp promoter involving backsplicing from the W1 and W2 exons to the C1 exon, from the EBNA BamHI U exon, and from the latency long-non-coding RPMS1 locus. We also identified circRNAs expressed during reactivation including an exon 8-to-2 backspliced LMP2 transcript and a highly expressed circRNA derived from the BHLF1 gene. Altogether we identified over 30 EBV circRNA candidates and validated and determined the structural features, expression profiles and nuclear-cytoplasmic distributions of several prominent viral circRNAs. Further, we show that two RPMS1 circRNAs are expressed in stomach cancer specimens. This study increases the known EBV latency and lytic transcriptome repertoires to include viral circRNAs and provides an essential foundation for investigations into the functions of this new class of EBV transcripts in EBV biology and disease.
Project description:BackgroundThe prospective application of plasma Epstein-Barr virus (EBV) DNA load as a noninvasive measure of intestinal EBV infection remains unexplored. This study aims to identify ideal threshold levels for plasma EBV DNA loads in the diagnosis and outcome prediction of intestinal EBV infection, particularly in cases of primary intestinal lymphoproliferative diseases and inflammatory bowel disease (IBD).MethodsReceiver operating characteristic (ROC) curves were examined to determine suitable thresholds for plasma EBV DNA load in diagnosing intestinal EBV infection and predicting its prognosis.Results108 patients were retrospectively assigned to the test group, while 56 patients were included in the validation group. Plasma EBV DNA loads were significantly higher in the intestinal EBV infection group compared to the non-intestinal EBV infection group (Median: 2.02 × 102 copies/mL, interquartile range [IQR]: 5.49 × 101-6.34×103 copies/mL versus 4.2×101 copies/mL, IQR: 1.07 ×101-6.08×101 copies/mL; P < 0.0001). Plasma EBV DNA levels at 9.21×101 and 6.77×101 copies/mL proved beneficial for the identification and prognostication in intestinal EBV infection, respectively. Values of 0.82 and 0.71 were yielded by the area under the ROC curve (AUC) in the test cohort, corresponding to sensitivities of 84.38% (95% confidence interval [95%CI]: 68.25%-93.14%) and 87.5% (95%CI: 69%-95.66%), specificities of 83.33% (95%CI: 64.15%-93.32%) and 68.09% (95%CI: 53.83%-79.6%), positive predictive values (PPV) of 87.1% (95%CI: 71.15%-94.87%) and 58.33% (95%CI: 42.2%-72.86%), and positive likelihood ratios (LR+) of 5.06 and 2.74 in the validation cohort, respectively. Furthermore, a plasma EBV DNA load of 5.4×102 copies/mL helped differentiate IBD with intestinal EBV infection from primary intestinal EBV-positive lymphoproliferative disorders (PIEBV+LPDs), achieving an AUC of 0.85 within the test cohort, as well as 85% sensitivity (95%CI: 63.96%-94.76%), 91.67% specificity (95%CI: 64.61%-99.57%), 94.44% PPV (95%CI: 74.24%-99.72%), and an LR+ of 10.2 in the validation cohort.ConclusionsPlasma EBV DNA load demonstrates notable potential in distinguishing between different patient cohorts with intestinal EBV infection, although its sensitivity requires further optimization for clinical application.
Project description:Rationale: Epstein-Barr virus (EBV) is associated with multiple malignancies with expression of viral oncogenic proteins and chronic inflammation as major mechanisms contributing to tumor development. A less well-studied mechanism is the integration of EBV into the human genome possibly at sites which may disrupt gene expression or genome stability. Methods: We sequenced tumor DNA to profile the EBV sequences by hybridization-based enrichment. Bioinformatic analysis was used to detect the breakpoints of EBV integrations in the genome of cancer cells. Results: We identified 197 breakpoints in nasopharyngeal carcinomas and other EBV-associated malignancies. EBV integrations were enriched at vulnerable regions of the human genome and were close to tumor suppressor and inflammation-related genes. We found that EBV integrations into the introns could decrease the expression of the inflammation-related genes, TNFAIP3, PARK2, and CDK15, in NPC tumors. In the EBV genome, the breakpoints were frequently at oriP or terminal repeats. These breakpoints were surrounded by microhomology sequences, consistent with a mechanism for integration involving viral genome replication and microhomology-mediated recombination. Conclusion: Our finding provides insight into the potential of EBV integration as an additional mechanism mediating tumorigenesis in EBV associated malignancies.
Project description:AimIn recent years, studies have suggested that Epstein-Barr virus (EBV) is associated with HCC. The present study was to determine the prevalence of EBV in HCC patients, and whether EBV acted synergistically with hepatitis viruses in HCC carcinogenesis.MethodsLiver tissue 115 HCC patients and 26 non-carcinoma patients were studied. Polymerase chain reaction (PCR) was performed to detect EBV BamHI W DNA, EBV LMP1 DNA, HBV X DNA, and HBV S DNA. Reverse transcription PCR (RT-PCR) was performed to detect HCV RNA and HDV RNA. Immunohistochemistry was performed to detect LMP1, HBsAg, HBcAg and HCV. The positive ratios were compared between HCC group and control group by chi2 test.ResultsTotally, 78 HCC samples whose beta-globulin DNA was positively detected by amplified PCR were selected. PCR was performed in all cases for EBV DNA and HBV DNA. RT-PCR was performed in 18 cases for HCV RNA and HDV RNA. EBV BamHI W and EBV LMP1 were positive in 18 and 6 cases, respectively. HBV X gene and HBV S gene were positive in 42 and 27 cases respectively. HCV was positive in one of the 18 cases, and none was positive for HDV. The positive rates were 28.2% (22 of 78) for EBV DNA (BamHI W and/or LMP1) and 56.4% (44 of 78) for HBV DNA (X gene and/or S gene) respectively. In addition, 12 cases were positive for both EBV DNA and HBV DNA. Among the 26 cases in the control group, 2 cases were positive for EBV BamHI W, 4 positive for HBV X gene and 3 positive for HBV S gene. The positive rates were 8.0% (2 of 26) and 23.1% (6 of 26), respectively, for EBV DNA and HBV DNA. The result of DNA sequencing of BamHI W was 100% homologous with the corresponding sequence of B95-8. There was significant difference in EBV infection rate between HCC patients and controls (chi2 = 4.622, P<0.05). The difference in HBV infection rate was also significant (chi2 = 8.681, P<0.05). However, there was no obvious correlation between HBV and EBV in HCC patients (chi2 = 0.835, P>0.05). LMP1, HBV (HBsAg, HBcAg) and HCV were detected positively in 25, 45 and 6 of 78 cases of HCC tissues respectively. In the 26 control cases, the corresponding positive cases were 2, 4 and 0. The difference in EBV infection rate between HCC patients and control cases was statistically significant (chi2 = 6.02, P<0.05). The difference in HBV infection rate was also statistically significant (chi2 = 10.03, P<0.05). In the 25 cases with positive LMP1 expression, 6 were in the nuclei of tumor cells, 9 in the cytoplasm of tumor cells and 10 in mesenchymal lymphocyte cytoplasm.ConclusionThe existence of EBV infection in HCC tissues suggests that EBV may be involved in the hepatocellular carcinogenesis in China. HBV infection may be a major cause of HCC. There is no correlation between EBV and HBV in the development of HCC. The prevalence of HCV infection is low in our area, and HDV appears not to play a direct role in hepatocellular carcinogenesis.
Project description:Epstein-Barr virus (EBV) is a ubiquitous human lymphotropic herpesvirus with a well-established causal role in several cancers. Recent studies have provided compelling epidemiological and mechanistic evidence for a causal role of EBV in multiple sclerosis (MS). MS is the most prevalent chronic inflammatory and neurodegenerative disease of the central nervous system and is thought to be triggered in genetically predisposed individuals by an infectious agent, with EBV as the lead candidate. How a ubiquitous virus that typically leads to benign latent infections can promote cancer and autoimmune disease in at-risk populations is not fully understood. Here we review the evidence that EBV is a causal agent for MS and how various risk factors may affect EBV infection and immune control. We focus on EBV contributing to MS through reprogramming of latently infected B lymphocytes and the chronic presentation of viral antigens as a potential source of autoreactivity through molecular mimicry. We consider how knowledge of EBV-associated cancers may be instructive for understanding the role of EBV in MS and discuss the potential for therapies that target EBV to treat MS.