Quantitative analysis of Epstein-Barr virus load by using a real-time PCR assay

Identification of Epstein–Barr virus-infected CD27+ memory B-cells in liver or stem cell transplant patients

To analyse the phenotype of Epstein–Barr virus (EBV)-infected lymphocytes in EBV-associated infections, cells from eight haematopoietic stem cell/liver transplantation recipients with elevated EBV viral loads were examined by a novel quantitative assay designed to identify EBV-infected cells by using a flow cytometric detection of fluorescent in situ hybridization (FISH) assay. By this assay, 0.05–0.78 % of peripheral blood lymphocytes tested positive for EBV, and the EBV-infected cells were CD20+ B-cells in all eight patients. Of the CD20+ EBV-infected lymphocytes, 48–83 % of cells tested IgD positive and 49–100 % of cells tested CD27 positive. Additionally, the number of EBV-infected cells assayed by using FISH was significantly correlated with the EBV-DNA load, as determined by real-time PCR (r 2 = 0.88, P<0.0001). The FISH assay enabled us to characterize EBV-infected cells and perform a quantitative analysis in patients with EBV infection after stem cell/liver transplantation.

Clinical characteristics of patients with Epstein Barr virus in cerebrospinal fluid

Background

The role of Epstein-Barr (EBV) virus in central nervous system (CNS) infections is not fully resolved. It is clearly associated with lymphoproliferative disease of immunosuppressed persons, and may cause encephalitis.

Methods

We reviewed the medical records, imaging and laboratory findings of all patients EBV DNA PCR positive in cerebrospinal fluid (CSF) during 2000 to 2009 in the Helsinki University Central Hospital.

Results

We identified 32 patients with EBV DNA in CSF. 11 had history of allogeneic hematopoietic stem cell transplantation, 7 solid organ transplantation and 5 HIV/AIDS. 5 patients had no preceding immunodeficiency.

In 8 of the cases, another pathogen was identified in CSF. These were M. tuberculosis (2), T. gondii (2), Aspergillus (1), Herpes simplex virus 1 (1), C. neoformans (1) and Human herpesvirus 6 (1). Altogether in 15/32 (47%) of the cases the clinician had a strong suspicion of cause other than EBV for the patients' CNS symptoms/findings.

Of note, 7 of 11 (64%) patients with stem cell transplantation had encephalitis (univariate odds ratio 5.6; confidence Interval 1.1-27.4). Of these 6 had no other pathogen identified.

Conclusions

EBV DNA was often found together with other microbial findings in CSF of immunocompromised patients. EBV seems to be associated with encephalitis in stem cell transplant recipients.

Novel mouse xenograft models reveal a critical role of CD4+ T cells in the proliferation of EBV-infected T and NK cells

Epstein-Barr virus (EBV), a ubiquitous B-lymphotropic herpesvirus, ectopically infects T or NK cells to cause severe diseases of unknown pathogenesis, including chronic active EBV infection (CAEBV) and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH). We developed xenograft models of CAEBV and EBV-HLH by transplanting patients' PBMC to immunodeficient mice of the NOD/Shi-scid/IL-2Rγ^null strain. In these models, EBV-infected T, NK, or B cells proliferated systemically and reproduced histological characteristics of the two diseases. Analysis of the TCR repertoire expression revealed that identical predominant EBV-infected T-cell clones proliferated in patients and corresponding mice transplanted with their PBMC. Expression of the EBV nuclear antigen 1 (EBNA1), the latent membrane protein 1 (LMP1), and LMP2, but not EBNA2, in the engrafted cells is consistent with the latency II program of EBV gene expression known in CAEBV. High levels of human cytokines, including IL-8, IFN-γ, and RANTES, were detected in the peripheral blood of the model mice, mirroring hypercytokinemia characteristic to both CAEBV and EBV-HLH. Transplantation of individual immunophenotypic subsets isolated from patients' PBMC as well as that of various combinations of these subsets revealed a critical role of CD4⁺ T cells in the engraftment of EBV-infected T and NK cells. In accordance with this finding, in vivo depletion of CD4⁺ T cells by the administration of the OKT4 antibody following transplantation of PBMC prevented the engraftment of EBV-infected T and NK cells. This is the first report of animal models of CAEBV and EBV-HLH that are expected to be useful tools in the development of novel therapeutic strategies for the treatment of the diseases.

Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that infects more than 90% of the adult human population in the world. EBV usually infects B lymphocytes and does not produce symptoms in infected individuals, but in rare occasions it infects T or NK lymphocytes and causes severe diseases such as chronic active EBV infection (CAEBV) and EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH). We developed mouse models of these two human diseases in which EBV-infected T or NK lymphocytes proliferate in mouse tissues and reproduce human pathologic conditions such as overproduction of small proteins called “cytokines” that produce inflammatory responses in the body. These mouse models are thought to be very useful for the elucidation of the pathogenesis of CAEBV and EBV-HLH as well as for the development of therapeutic strategies for the treatment of these diseases. Experiments with the models demonstrated that a subset of lymphocytes called CD4-positive lymphocytes are essential for the proliferation of EBV-infected T and NK cells. This result implies that removal of CD4-positive lymphocytes or suppression of their functions may be an effective strategy for the treatment of CAEBV and EBV-HLH.

Epstein-Barr virus induces erosive arthritis in humanized mice

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of rheumatoid arthritis (RA) on the basis of indirect evidence, such as its presence in affected joint tissues, antigenic cross reactions between EBV and human proteins, and elevated humoral and cellular anti-EBV immune responses in patients. Here we report development of erosive arthritis closely resembling RA in humanized mice inoculated with EBV. Human immune system components were reconstituted in mice of the NOD/Shi-scid/IL-2Rγ^null (NOG) strain by transplantation with CD34⁺ hematopoietic stem cells isolated from cord blood. These humanized mice were then inoculated with EBV and examined pathologically for the signs of arthritis. Erosive arthritis accompanied by synovial membrane proliferation, pannus formation, and bone marrow edema developed in fifteen of twenty-three NOG mice transplanted with human HSC and inoculated with EBV, but not in the nine NOG mice that were transplanted with HSC but not inoculated with EBV. This is the first report of an animal model of EBV-induced arthritis and strongly suggest a causative role of the virus in RA.

Replication of Epstein-Barr virus primary infection in human tonsil tissue explants

Epstein-Barr virus (EBV) may cause a variety of virus-associated diseases, but no antiviral agents have yet been developed against this virus. Animal models are thus indispensable for the pathological analysis of EBV-related infections and the elucidation of therapeutic methods. To establish a model system for the study of EBV infection, we tested the ability of B95–8 virus and recombinant EBV expressing enhanced green fluorescent protein (EGFP) to replicate in human lymphoid tissue. Human tonsil tissues that had been surgically removed during routine tonsillectomy were sectioned into small blocks and placed on top of collagen sponge gels in culture medium at the air-interface, then a cell-free viral suspension was directly applied to the top of each tissue block. Increasing levels of EBV DNA in culture medium were observed after 12–15 days through 24 days post-infection in tissue models infected with B95–8 and EGFP-EBV. Expression levels of eight EBV-associated genes in cells collected from culture medium were increased during culture. EBV-encoded small RNA-positive cells were detected in the interfollicular areas in paraffin-embedded sections. Flow cytometric analyses revealed that most EGFP⁺ cells were CD3⁻ CD56⁻ CD19⁺ HLA-DR⁺, and represented both naïve (immunoglobulin D⁺) and memory (CD27⁺) B cells. Moreover, EBV replication in this model was suppressed by acyclovir treatment in a dose-dependent manner. These data suggest that this model has potential for use in the pathological analysis of local tissues at the time of primary infection, as well as for screening novel antiviral agents.

Comparison of QIAsymphony automated and QIAamp manual DNA extraction systems for measuring Epstein-Barr virus DNA load in whole blood using real-time PCR

Automated and manual extraction systems have been used with real-time PCR for quantification of Epstein-Barr virus [human herpesvirus 4 (HHV-4)] DNA in whole blood, but few studies have evaluated relative performances. In the present study, the automated QIAsymphony and manual QIAamp extraction systems (Qiagen, Valencia, CA) were assessed using paired aliquots derived from clinical whole-blood specimens and an in-house, real-time PCR assay. The detection limits using the QIAsymphony and QIAamp systems were similar (270 and 560 copies/mL, respectively). For samples estimated as having ≥10,000 copies/mL, the intrarun and interrun variations were significantly lower using QIAsymphony (10.0% and 6.8%, respectively), compared with QIAamp (18.6% and 15.2%, respectively); for samples having ≤1000 copies/mL, the two variations ranged from 27.9% to 43.9% and were not significantly different between the two systems. Among 68 paired clinical samples, 48 pairs yielded viral loads ≥1000 copies/mL under both extraction systems. Although the logarithmic linear correlation from these positive samples was high (r(2) = 0.957), the values obtained using QIAsymphony were on average 0.2 log copies/mL higher than those obtained using QIAamp. Thus, the QIAsymphony and QIAamp systems provide similar EBV DNA load values in whole blood.

A multiplex calibrated real-time PCR assay for quantitation of DNA of EBV-1 and 2

Accurate and highly sensitive tests for the diagnosis of active Epstein-Barr virus (EBV) infection are essential for the clinical management of individuals infected with EBV. A calibrated quantitative real-time PCR assay for the measurement of EBV DNA of both EBV-1 and 2 subtypes was developed, combining the detection of the EBV DNA and a synthetic DNA calibrator in a multiplex PCR format. The assay displays a wide dynamic range and a high degree of accuracy even in the presence of 1μg of human genomic DNA. This assay measures with the same efficiency EBV DNA from strains prevalent in different geographic areas. The clinical sensitivity and specificity of the system were evaluated by testing 181 peripheral blood mononuclear cell (PBMCs) and plasma specimens obtained from 21 patients subjected to bone marrow transplantation, 70 HIV-seropositive subjects and 23 healthy controls. Patients affected by EBV-associated post-transplant lymphoprolipherative disorders had the highest frequency of EBV detection and the highest viral load. Persons infected with HIV had higher levels of EBV DNA load in PBMCs and a higher frequency of EBV plasma viremia compared to healthy controls. In conclusion, this new assay provides a reliable high-throughput method for the quantitation of EBV DNA in clinical samples.

Salivary Epstein-Barr virus DNA level in patients with nasopharyngeal carcinoma following radiotherapy

Nasopharyngeal carcinoma (NPC) is a solid tumor closely associated with Epstein-Barr virus (EBV) infection. The purpose of this investigation was to detect and quantify the EBV DNA level in salivary samples of NPC patients following treatment using real-time PCR. A total of 175 consecutive newly diagnosed NPC patients' whole saliva samples were collected before treatment, and the EBV DNA level was measured by real-time PCR, with the primers and probe targeting the BamHI-W region of the EBV genome. The post-treatment salivary EBV DNA level was also assessed in 46 patients. The change of EBV DNA level before and after treatment and relationship of EBV DNA level to demographic data and tumor staging were tested by Wilcoxon signed-rank test and Mann-Whitney U test, respectively with the level of significance set at 0.05. The EBV detection rate of pre-treatment saliva samples was 80%. The EBV DNA level of post-treatment saliva samples was significantly higher than the pre-treatment ones (P<0.01). There is a trend that patients with advanced-stage showed a higher EBV DNA level than patients with early-stage. The detection of EBV DNA in saliva using real-time PCR might be a feasible and non-invasive method for early diagnosis of NPC.

Epstein-Barr virus infection in transplant recipients: Summary of a workshop on surveillance, prevention and treatment

Diseases caused by the Epstein-Barr virus are of great significance among organ transplant recipients. One of these diseases, post-transplant lymphoproliferative disease, is a major complication among organ transplant recipients. Management of this entity is problematic due to the difficulties with laboratory surveillance, diagnosis, prevention and treatment. A group of Canadian and American experts was assembled to discuss these aspects of Epstein-Barr virus diseases in Canadian organ transplant recipients. This report summarizes the relevant background literature and levels of evidence in relation to the outcomes of the deliberations and recommendations by the expert panel.

Valganciclovir reduces T cell activation in HIV-infected individuals with incomplete CD4+ T cell recovery on antiretroviral therapy

BACKGROUND

Elevated immune activation persists during treated human immunodeficiency virus (HIV) infection and is associated with blunted CD4 recovery and premature mortality, but its causes remain incompletely characterized. We hypothesized that asymptomatic cytomegalovirus (CMV) replication might contribute to immune activation in this setting.

METHODS

Thirty antiretroviral therapy-treated HIV-infected CMV-seropositive participants with CD4 counts <350 cells/mm(3) were randomized to receive valganciclovir 900 mg daily or placebo for 8 weeks, followed by an additional 4-week observation period. The primary outcome was the week 8 change in percentage of activated (CD38(+) HLA-DR(+)) CD8(+) T cells.

RESULTS

Fourteen participants were randomized to valganciclovir and 16 to placebo. Most participants (21 [70%] of 30) had plasma HIV RNA levels <75 copies/mL. The median CD4 count was 190 (IQR: 134-232) cells/mm(3), and 12 (40%) of 30 had detectable CMV DNA in saliva, plasma, or semen at baseline. CMV DNA continued to be detectable at weeks 4-12 in 7 (44%) of 16 placebo-treated participants, but in none of the valganciclovir-treated participants (P = .007). Valganciclovir-treated participants had significantly greater reductions in CD8 activation at weeks 8 (P = .03) and 12 (P = .02) than did placebo-treated participants. These trends were significant even among those with undetectable plasma HIV RNA levels.

CONCLUSIONS

CMV (and/or other herpesvirus) replication is a significant cause of immune activation in HIV-infected individuals with incomplete antiretroviral therapy-mediated CD4(+) T cell recovery.

CLINICAL TRIALS REGISTRATION

NCT00264290.

The clinical value of concomitant Epstein Barr virus (EBV)-DNA load and specific immune reconstitution monitoring after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Monitoring of EBV DNAemia after allogeneic hematopoietic stem cell transplantation (HSCT) is necessary, but not sufficient, to identify patients at risk of EBV-induced post-transplantation lymphoproliferative disorders (PTLD). Combining this with quantifying EBV-specific cellular immunity was shown to be helpful. In this study, we evaluated the value of IFNγ-Elispot assay in monitoring EBV DNAemia after HSCT.

METHODS

EBV-DNA load in whole blood was monitored at least weekly using real-time PCR in 40 recipients of HSCT. Quantitative and qualitative T-cell recoveries, including EBV-specific T-cell quantification by Elispot assay, were studied 60, 100, 180 and 360 days after HSCT.

RESULTS

Among the 35 evaluable patients, 14 (35%) presented EBV DNAemia, only 2/14 (14%) needing pre-emptive treatment with rituximab. The greatest risk factor for EBV DNAemia was the presence of anti-thymocyte globulin (ATG) (p=0.005). EBV-specific cellular immune recovery was monitored by IFNγ-Elispot assay. Using multivariate analysis, four factors were found to significantly influence IFNγ-Elispot results at defined times post-HSCT: EBV DNAemia, young age, global T-cell recovery and severe acute GVHD. In those cases where EBV DNAemia occurred and cleared spontaneously, Elispot results gave more than 1000 spot-forming cells (SFC)/10(6)PBMC.

CONCLUSION

Elispot assay may be usefully combined with EBV-DNA load monitoring to determine when a patient should receive pre-emptive treatment, or when the clinician should avoid Rituximab use which severely immunocompromises patients.

Reactivations of cytomegalovirus, human herpes virus 6, and Epstein-Barr virus differ with respect to risk factors and clinical outcome after hematopoietic stem cell transplantation

One hundred two recipients of hematopoietic stem cell transplants (HSCTs) 45, from siblings and 57 from matched unrelated donors, were followed for cytomegalovirus (CMV), human herpes virus (HHV) 6, and Epstein-Barr Virus (EBV) reactivation by quantitative polymerase chain reaction in the context of immunologic reconstitution and posttransplantation complications. CMV, EBV, and HHV6 DNA copies (>100 copies/10(5) cells) were detected in 34%, 27%, and 26% of patients, respectively. The presence of 100 copies of EBV or CMV was associated with posttransplant complications: 29/66 versus 6/36 (P<.01) or 24/66 versus 4/36 (P=.01). CMV reactivation was more frequent among patients with acute graft-versus-host disease grade≥I: 17/35 versus 18/67 (P<.05). Older patient age of adults>16 year (2/16 versus 33/86; P<.05) and, to a lesser extent, CMV IgG positivity before HSCT (34/84 versus 1/10; P=.08) or an HLA-mismatched graft (9/16 versus 26/86; P=.08) constituted risk factors for CMV reactivation, which resulted in a higher rate of bacterial pneumonia (7/11 versus 28/91; P=.04). EBV reactivation risk was associated with donor EBV IgG seropositivity (28/84 versus 0/10; P=.03) and donor female gender (18/47 versus 10/55; P=.03). In contrast to EBV and CMV, EBV reactivation itself was associated with encephalitis (5/8 versus 23/94; P=.013), which was also seen as a trend among HHV6 reactivations (8/8 versus 46/94; P=.08). Multivariate analysis demonstrated that these factors play independent roles in the reactivation of the investigated herpes viruses.

Epstein-Barr virus replication linked to B cell proliferation in inflamed areas of colonic mucosa of patients with inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract. Epstein-Barr virus (EBV) infection is associated with increased disease severity in therapeutically immunosuppressed IBD patients. The role of EBV infection in patients with IBD who are unresponsive to medical therapy is unclear. Anti-viral strategies may be a viable treatment option if severity of EBV infection, reflected in peripheral blood, contributes to IBD progression.

OBJECTIVES

We investigated the role of EBV in IBD patients unresponsive to medical therapy by examining EBV reactivation and B-cell proliferation in colonic mucosa.

STUDY DESIGN

EBV DNA copy numbers were measured by real-time PCR in peripheral blood mononuclear cells (PBMC) of 84 patients with IBD and 115 non-IBD controls in a retrospective cross-sectional study. EBV-infected cells in colonic mucosa were identified by immunohistochemistry.

RESULTS

EBV load in PBMC was higher in patients with IBD than in non-IBD controls, especially in patients not responding to medication. Inflamed colonic mucosa of these patients had high levels of expression of lytic and latent EBV genes that localized to proliferating B-lymphocytes, which was not seen in patients responding to therapy.

CONCLUSIONS

EBV replication was associated with severe IBD and mucosal inflammation. Increased proliferation and EBV infection of B-lymphocytes in inflamed colonic mucosa highlight the potential role of EBV in mucosal inflammation. The immunomodulatory effects of EBV could delay the resolution of the IBD associated inflammation, thus contributing to disease progression. These results indicate that anti-viral therapeutic strategies for the resolution of IBD may be useful.

Plasma EBV-DNA monitoring in Epstein-Barr virus-positive Hodgkin lymphoma patients

Epstein-Barr virus (EBV) is associated with approximately one-third of Hodgkin lymphoma (HL) cases. EBV-DNA is often present in the plasma and whole blood of EBV-associated HL patients. However, the significance of EBV-DNA monitoring is debated. In a cohort of 165 adult HL patients, EBV-DNA viral load was prospectively monitored both in the plasma and whole blood. Diagnostic tissue samples of all patients were histologically reviewed; in 72% nodular sclerosis was detected, 24% presented with mixed cellularity (MC), and 5% had other type of HL. Tissues from 150 patients were also analyzed for the presence of latent EBV infection using in situ hybridization for EBV-encoded RNA (EBER) and immunohistochemistry for latent membrane protein (LMP1). Using these methods, 29 (19%) patients were classified as EBV positive. Using real-time quantitative PCR, 22 (76%) of EBV-positive HL patients had detectable EBV-DNA in the plasma and 19 (66%) patients in whole blood prior to therapy. In the group of EBV-negative HL cases, three (2%) patients had detectable plasma EBV-DNA and 30 (25%) patients whole blood EBV-DNA before treatment. EBV-positive HL was significantly associated with EBV-DNA positivity both in the plasma and whole blood in pretreatment samples, increasing age and MC subtype. Serial analysis of plasma EBV-DNA showed that response to therapy was associated with decline in viral load. Moreover, significantly increased plasma EBV-DNA level recurred before disease relapse in one patient. Our results further suggest that the assessment of plasma EBV-DNA viral load might be of value for estimation of prognosis and follow-up of patients with EBV-positive HL.

Detection of DNA of six human herpesviruses in the cerebrospinal fluid of immunocompetent non-herpetic acute limbic encephalitis patients

In order to determine whether six other human herpesviruses, aside from herpes simplex virus, are associated with non-herpetic acute limbic encephalitis in immunocompetent individuals, real-time PCR was used to detect the DNA of herpesviruses in CSF collected from 61 patients with this form of encephalitis. Five of the human herpesviruses tested were not detected in any of the 61 CSF samples. EBV DNA was detected in one CSF sample. The EBV DNA-positive patient was a 36-year-old woman who presented with fever, headache, mild somnolence, and the typical neuroimaging findings.

Glucocorticoids activate Epstein Barr virus lytic replication through the upregulation of immediate early BZLF1 gene expression

Psychological stress-associated immune dysregulation has been shown to disrupt the steady-state expression and reactivate latent herpes viruses. One such virus is the Epstein Barr virus (EBV), which is associated with several human malignancies. EBV infects >90% of people living in North America and persists for life in latently infected cells. Although several studies have shown that glucocorticoids (GCs) can directly induce reactivation of the latent virus, the mechanism of stress hormone involvement in the control of EBV gene expression is not well understood. In this study, we tested the hypothesis that GCs can induce the latent EBV genome to lytically replicate through the induction of the EBV immediate early gene BZLF1 which encodes the lytic transactivator protein ZEBRA. We show a dose-dependent upregulation of BZLF1 mRNA expression by hydrocortisone (HC) and dexamethasone (Dex) in Daudi cells, an EBV genome positive Burkitt's lymphoma cell line, and Dex-induction of the early gene products BLLF3 (encoding for the EBV dUTPase) and BALF5 (encoding for the EBV DNA polymerase). We show that Daudi cells express glucocorticoid receptors (GR) that mediate Dex-dependent upregulation of BZLF1 mRNA levels. This effect was inhibited by both the glucocorticoid receptor antagonist RU486 and by cycloheximide. The results suggest that GCs, in addition to inducing stress-related immune dysregulation, can mediate latent EBV reactivation through the induction of the BZLF1 gene.

Measurement of Epstein-Barr virus DNA load using a novel quantification standard containing two EBV DNA targets and SYBR Green I dye

Background

Reactivation of Epstein-Barr virus (EBV) infection may cause serious, life-threatening complications in immunocompromised individuals. EBV DNA is often detected in EBV-associated disease states, with viral load believed to be a reflection of virus activity. Two separate real-time quantitative polymerase chain reaction (QPCR) assays using SYBR Green I dye and a single quantification standard containing two EBV genes, Epstein-Barr nuclear antigen-1 (EBNA-1) and BamHI fragment H rightward open reading frame-1 (BHRF-1), were developed to detect and measure absolute EBV DNA load in patients with various EBV-associated diseases. EBV DNA loads and viral capsid antigen (VCA) IgG antibody titres were also quantified on a population sample.

Results

EBV DNA was measurable in ethylenediaminetetraacetic acid (EDTA) whole blood, peripheral blood mononuclear cells (PBMCs), plasma and cerebrospinal fluid (CSF) samples. EBV DNA loads were detectable from 8.0 × 10² to 1.3 × 10⁸ copies/ml in post-transplant lymphoproliferative disease (n = 5), 1.5 × 10³ to 2.0 × 10⁵ copies/ml in infectious mononucleosis (n = 7), 7.5 × 10⁴ to 1.1 × 10⁵ copies/ml in EBV-associated haemophagocytic syndrome (n = 1), 2.0 × 10² to 5.6 × 10³ copies/ml in HIV-infected patients (n = 12), and 2.0 × 10² to 9.1 × 10⁴ copies/ml in the population sample (n = 218). EBNA-1 and BHRF-1 DNA were detected in 11.0% and 21.6% of the population sample respectively. There was a modest correlation between VCA IgG antibody titre and BHRF-1 DNA load (rho = 0.13, p = 0.05) but not EBNA-1 DNA load (rho = 0.11, p = 0.11).

Conclusion

Two sensitive and specific real-time PCR assays using SYBR Green I dye and a single quantification standard containing two EBV DNA targets, were developed for the detection and measurement of EBV DNA load in a variety of clinical samples. These assays have application in the investigation of EBV-related illnesses in immunocompromised individuals.

A case of unilateral optic disc swelling with chronic active Epstein-Barr virus infection

Ocular complications of chronic active Epstein-Barr virus (EBV) infection have rarely been reported and are usually associated with systemic symptoms. We described a 17-year-old boy with unilateral optic disc swelling without any systemic symptoms at the initial onset. Antibody titers to EBV were markedly elevated. Treatment with immunosuppressants and corticosteroids dramatically relieved all his symptoms, including unilateral optic swelling and visual field abnormalities.

EBV Chronic Infections

The infection from Epstein-Barr virus (EBV) or virus of infectious mononucleosis, together with other herpes viruses' infections, represents a prototype of persistent viral infections characterized by the property of the latency. Although the reactivations of the latent infection are associated with the resumption of the viral replication and eventually with the "shedding", it is still not clear if this virus can determine chronic infectious diseases, more or less evolutive. These diseases could include some pathological conditions actually defined as "idiopathic"and characterized by the "viral persistence" as the more credible pathogenetic factor. Among the so-called idiopathic syndromes, the "chronic fatigue syndrome" (CFS) aroused a great interest around the eighties of the last century when, just for its relationship with EBV, it was called "chronic mononucleosis" or "chronic EBV infection".Today CFS, as defined in 1994 by the CDC of Atlanta (USA), really represents a multifactorial syndrome characterized by a chronic course, where reactivation and remission phases alternate, and by a good prognosis. The etiopathogenetic role of EBV is demonstrated only in a well-examined subgroup of patients, while in most of the remaining cases this role should be played by other infectious agents - able to remain in a latent or persistent way in the host - or even by not infectious agents (toxic, neuroendocrine, methabolic, etc.). However, the pathogenetic substrate of the different etiologic forms seems to be the same, much probably represented by the oxidative damage due to the release of pro-inflammatory cytokines as a response to the triggering event (infectious or not infectious).Anyway, recently the scientists turned their's attention to the genetic predisposition of the subjects affected by the syndrome, so that in the last years the genetic studies, together with those of molecular biology, received a great impulse. Thanks to both these studies it was possibile to confirm the etiologic links between the syndrome and EBV or other herpesviruses or other persistent infectious agents.The mechanisms of EBV latency have been carefully examined both because they represent the virus strategy to elude the response of the immune system of the host, and because they are correlated with those oncologic conditions associated to the viral persistence, particularly lymphomas and lymphoproliferative disorders. Just these malignancies, for which a pathogenetic role of EBV is clearly documented, should represent the main clinical expression of a first group of chronic EBV infections characterized by a natural history where the neoplastic event aroused from the viral persistence in the resting B cells for all the life, from the genetic predisposition of the host and from the oncogenic potentialities of the virus that chronically persists and incurs reactivations.Really, these oncological diseases should be considered more complications than chronic forms of the illness, as well as other malignancies for which a viral - or even infectious - etiology is well recognized. The chronic diseases, in fact, should be linked in a pathogenetic and temporal way to the acute infection, from whom start the natural history of the following disease. So, as for the chronic liver diseases from HBV and HCV, it was conied the acronym of CAEBV (Chronic Active EBV infection), distinguishing within these pathologies the more severe forms (SCAEBV) mostly reported in Far East and among children or adolescents. Probably only these forms have to be considered expressions of a chronic EBV infection "sensu scrictu", together with those forms of CFS where the etiopathogenetic and temporal link with the acute EBV infection is well documented. As for CFS, also for CAEBV the criteria for a case definition were defined, even on the basis of serological and virological findings. However, the lymphoproliferative disorders are excluded from these forms and mantain their nosographic (e.g. T or B cell or NK type lymphomas) and pathogenetic collocation, even when they occur within chronic forms of EBV infection. In the pathogenesis, near to the programs of latency of the virus, the genetic and environmental factors, independent from the real natural history of EBV infection, play a crucial role.Finally, it was realized a review of cases - not much numerous in literature - of chronic EBV infection associated to chronic liver and neurological diseases, where the modern techniques of molecular biology should be useful to obtain a more exact etiologic definition, not always possibile to reach in the past.The wide variety of clinical forms associated to the EBV chronic infection makes difficult the finding of a univocal pathogenetic link. There is no doubt, however, that a careful examination of the different clinical forms described in this review should be useful to open new horizons to the study of the persistent viral infections and the still not well cleared pathologies that they can induce in the human host.

Epstein-Barr virus can infect rabbits by the intranasal or peroral route: an animal model for natural primary EBV infection in humans

Epstein-Barr virus (EBV) is spread universally in humans, and it causes infectious mononucleosis and sometimes induces serious EBV-associated disease. The detailed mechanism of primary infection in humans has remained unclear, because it is difficult to examine the dynamics of EBV in vivo. In this study, a natural EBV-infection rabbit model by intranasal or peroral inoculation is described. Ten male rabbits were examined for EBV-DNA or mRNA expression and anti-EBV antibodies in blood. Four of 10 rabbits showed the evidence of EBV infection; detection of EBV-DNA or EBV-related genes mRNA in peripheral blood mononuclear cells, increased EBV antibodies in the plasma, and the presence of lymphocytes expressing EBER1 and EBV-related gene proteins in the lymphoid tissues of a rabbit. Three of four infected rabbits were detected transiently EBV-DNA and/or mRNA of EBV-related genes such as EBNA1, EBNA2, BZLF1, and EA in blood, while in one of four, EBV-DNA and/or mRNA were detected for more than 200 days after viral inoculation. The level of EA-IgG increased and its level was maintained in all infected rabbits, whereas those of VCA-IgM and VCA-IgG increased transiently, and EBNA-IgG was not elevated. Pathological examination of a rabbit infected transiently revealed some scattered lymphocytes expressing EBER1, LMP1, and EBNA2 in the spleen and lymph nodes. EA expression was also observed in the spleen. These findings suggest that EBV can infect the rabbit by the intranasal or peroral route, and that this rabbit model is useful for examining the pathophysiology of natural primary EBV infection in humans.

Subclinical viremia increases risk for chronic allograft injury in pediatric renal transplantation

The impact of subclinical viral infection on chronic allograft injury in the pediatric renal transplant population is not well defined. We prospectively assessed cytomegalovirus (CMV) and Epstein-Barr virus (EBV) DNAemia by monthly PCR in 55 pediatric renal transplant recipients for the first 2 years after transplantation. Subclinical CMV and EBV infection occurred in 22 and 36%, respectively. Multivariable linear regression analysis suggested that both subclinical CMV and EBV infection independently associate with significant declines in GFR during the first 2 years after transplantation. CMV seronegativity associated with a significantly greater decline in GFR than seropositivity (P < 0.01). Subclinical CMV infection and subclinical EBV infection each associated with approximately fourfold greater odds of histologic evidence of chronic allograft injury (odds ratio 4.61 [95% confidence interval 1.18 to 18.07] and odds ratio 4.33 [95% confidence interval 1.34 to 14.00], respectively). An increase in viral load of CMV or EBV also associated with increased risk for moderate to severe chronic allograft injury. Taken together, these results demonstrate an association between subclinical CMV and EBV infections, which occur despite standard antiviral prophylaxis, and chronic allograft injury in pediatric renal transplant recipients.

Elevated Epstein-Barr virus loads and lower antibody titers in competitive athletes

Epstein-Barr virus (EBV) is a persisting herpesvirus which is controlled by the adaptive immune response after primary infection and maintained in a latent state. However, reactivation or persistent replication is observed in situations where the immune response is compromised. Since intensive physical training has been reported to diminish immune function, increased EBV load may be a cause of reduced performance and decreased ability to sustain high training loads in competitive athletes. Samples drawn from 209 athletes during their regular follow-up appointments were tested. One hundred sixty-five individuals of similar age not active in competitive sports served as case-controls. EBV load was quantified in peripheral blood leucocytes (PBLs) by real-time PCR, and EBV antibodies were detected in plasma by ELISA and immunoblot analysis. EBV DNA was detectable in 25 of 209 athletes and in 26 of 165 controls. Of note, the EBV load per 10(5) PBLs was 6.44 +/- 1.75 in the case and 1.67 +/- 0.44 copies in the controls, yielding a high significant difference (P < 0.0001). However, EBV-specific IgG titers were significantly lower in athletes (150.4 +/- 10.73 U ml(-1) vs. 241.6 +/- 18.59 U ml(-1)). As monitored by immunoblotting, primary infections were detected with low prevalence, three in the case group and one in the control group. These findings demonstrate that EBV is present at higher levels in athletes, but the antibody response is lower in athletes than in the controls. J. Med. Virol. 82:446-451, 2010. (c) 2010 Wiley-Liss, Inc.

Multiplex real-time PCR assay for simultaneous quantification of BK polyomavirus, JC polyomavirus, and adenovirus DNA

In recent years, virus-induced nephropathy caused mainly by BK polyomavirus (BKPyV), JC polyomavirus (JCPyV), and adenovirus has emerged as a problem in renal transplant patients. In the present study, we developed a multiplex real-time PCR assay to quantify the viral load of BKPyV, JCPyV, and adenovirus simultaneously. The dynamic range covered at least 6 orders of magnitude. This system was specific and reproducible, even in the presence of large amounts of DNA of other viruses. To validate this assay, urine samples from 124 renal transplant patients and serum samples from 18 hemorrhagic cystitis patients after hematopoietic stem cell transplantation were examined. In the urine samples from renal transplant patients, BKPyV was detected in 28 patients (22.6%), JCPyV was detected in 51 patients (41.1%), and adenovirus was detected in 2 patients (1.6%). The maximum amounts of each virus detected were 2.7 x 10(9), 8.7 x 10(8), and 1.2 x 10(2) copies/ml, respectively. Decoy cells were observed in 31 patients. The quantities of both BKPyV and JCPyV DNA were greater in samples with decoy cells. Two patients whose BKPyV viral loads exceeded 10(8) copies/ml had elevated serum creatinine levels and were diagnosed with BKPyV nephropathy based on graft biopsies. In serum samples from hemorrhagic cystitis patients, BKPyV, JCPyV, and adenovirus was detected in six, two, and three patients, respectively. Strong correlations were observed between the viral DNA copy numbers determined in the multiplex assays and those determined in single assays. Since this new assay is rapid, sensitive, and specific, it can be used for quantitative analyses of viruses in urine and serum samples after transplantation.

Successful allogeneic hematopoietic stem cell transplantation for aggressive NK cell leukemia

Aggressive natural killer cell leukemia (ANKL) is a highly aggressive lymphoproliferative disease. An appropriate therapeutic strategy for ANKL remains to be established, but a few case reports have suggested that allogeneic hematopoietic stem cell transplantation (allo-HCT) can be curative. Here, we report a young woman with ANKL showing central nervous system (CNS) invasion, who has been in complete remission for more than a year after allo-HCT following two courses of intravenous chemotherapy and several rounds of intrathecal chemotherapy. Intensive remission induction chemotherapy followed by conventional myeloablative allo-HCT is a promising approach for long-term remission in cases of this aggressive malignancy.

Quantitative analysis of Epstein-Barr virus (EBV)-related gene expression in patients with chronic active EBV infection

Chronic active Epstein-Barr virus (CAEBV) infection is a systemic Epstein-Barr virus (EBV)-positive lymphoproliferative disorder characterized by persistent or recurrent infectious mononucleosis-like symptoms in patients with no known immunodeficiency. The detailed pathogenesis of the disease is unknown and no standard treatment regimen has been developed. EBV gene expression was analysed in peripheral blood samples collected from 24 patients with CAEBV infection. The expression levels of six latent and two lytic EBV genes were quantified by real-time RT-PCR. EBV-encoded small RNA 1 and BamHI-A rightward transcripts were abundantly detected in all patients, and latent membrane protein (LMP) 2 was observed in most patients. EBV nuclear antigen (EBNA) 1 and LMP1 were detected less frequently and were expressed at lower levels. EBNA2 and the two lytic genes were not detected in any of the patients. The pattern of latent gene expression was determined to be latency type II. EBNA1 was detected more frequently and at higher levels in the clinically active patients. Quantifying EBV gene expression is useful in clarifying the pathogenesis of CAEBV infection and may provide information regarding a patient's disease prognosis, as well as possible therapeutic interventions.

Clinical characteristics, outcome and the role of viral load in nontransplant patients with Epstein-Barr viraemia

Epstein-Barr virus (EBV) is important in the development of post-transplant lymphoproliferative disease in allogeneic stem cell and solid organ transplant recipients. We have studied the clinical significance of EBV DNAaemia among nontransplant patients in a tertiary referral hospital. We retrospectively reviewed the medical records for main diagnosis, outcome, immunosuppressive/cytotoxic chemotherapy and other opportunistic infections of the patients who were found positive in quantitative real-time PCR assay for EBV (EBV-qPCR) between the years 2000 and 2007. Allogeneic stem cell and solid organ transplant recipients were excluded, and all patients in nonsurgical adult wards were included. Altogether, 62 patients had at least one plasma sample positive with an EBV-qPCR. Fifteen were immunocompetent, most had primary EBV infection, and the outcome was good. On the other hand, 36 had malignant disease, seven had HIV infection and seven had immunosuppressive conditions of an other aetiology. All but one of the malignancies were of lymphoid origin, and most of these patients had a history of multiple cytotoxic treatments. Immunosuppressed patients had higher viral loads. EBV viraemia is associated with severe immunosuppression and lymphoid malignancies.

Cytomegalovirus and Epstein-Barr virus coinfection in three toddlers with prolonged illnesses

Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) usually cause primary and latent infections during childhood; thus, coinfection with these viruses occurs occasionally in children. However, its clinical impact has not been established, and may be underestimated. Three cases of coinfection involving these two viruses in toddlers are described: a 14-month-old male with infectious mononucleosis, an 18-month-old female with hemophagocytic lymphohistiocytosis, and a 13-month-old female with acute hepatitis. All three patients had prolonged illnesses. Serial serological testing and quantitation of viral DNA for CMV and EBV using peripheral blood from the patients suggested primary infections with both viruses. In all three cases, the viral load of EBV and CMV in the early stage of disease exceeded 6.4 x 10(3) and 8.8 x 10(2) copies/ml of whole blood, respectively, suggesting that the viruses were associated with the clinical condition. Recognizing that coinfection with these viruses may modulate the clinical course of disease is important.

Bilateral facial nerve palsy associated with Epstein-Barr virus infection with a review of the literature

A case of bilateral simultaneous facial nerve palsy associated with an Epstein-Barr virus (EBV) infection in a 14-month-old girl is described. Diagnosis of the EBV infection was based on the presence of 7% atypical lymphocytes, EBV-DNA and seroconversion in the VCA-IgG antibody, an EBV-specific antibody. Although bilateral facial nerve palsy is very rare, approximately 40% of the EBV-associated facial nerve palsy cases reported have been bilateral.

Significance of Epstein-Barr virus (EBV) load and Interleukin-10 in post-transplant lymphoproliferative disorders

The complex relationship between EBV, IL-10 and lymphomagenesis has been widely investigated and several studies have highlighted the diagnostic value of EBV DNA copies and serum IL-10, that may be considered as tumor markers. Notwithstanding the great number of data published in the last few years on the behavior of EBV DNA copies in the peripheral blood of transplanted patients, a threshold value significant for impending or overt post-transplant lymphoproliferative disorder (PTLD) has not yet been defined. Too many factors, both technical and clinicopathological, may affect the results of clinical studies, making their comparison difficult. On the contrary, although the role of IL-10 in PTLDs has been well documented, a sufficient number of studies exploring sensitivity and specificity of serum IL-10 measurement is lacking. The aim of this review is to summarise data on EBV load quantification and serum IL-10 detection in transplanted patients, providing clinicians with wide and useful information in order to improve bedside management of transplanted patients with regard to PTLDs occurrence and treatment.

Preemptive management of Epstein-Barr virus reactivation after hematopoietic stem-cell transplantation

BACKGROUND

Epstein-Barr virus (EBV) reactivation after hematopoietic stem-cell transplantation can lead to posttransplant lymphoproliferative disease (PTLD), which carries a high mortality rate. Among therapeutic and prophylactic options being developed, B-cell depletion with monoclonal antibodies is encouraging. Because viral load after transplantation is correlated with PTLD occurrence, we developed a preemptive attitude based on polymerase chain reaction (PCR)-guided rituximab administration.

METHODS

We monitored 115 transplant patients with a quantitative PCR for EBV DNA performed on whole-blood samples. Criteria for treatment initiation were a single PCR above 40,000 DNA genome copies per milliliter (gCop/mL) or two rising values above 10,000 gCop/mL. Weekly rituximab infusion at the dose of 375 mg/m was administered until negative PCR results were available. We evaluated the incidence of EBV reactivation and PTLD development.

RESULTS

Nineteen patients (16.5%) met the criteria for treatment. Incidence of reactivation was the same in high-risk and standard-risk patients (12 vs. 7, P=0.38). One patient developed PTLD after discontinuation of therapy due to a serious adverse event. No other serious adverse events were noticed. Viral load disappeared after a median of three cycles of therapy, and weekly monitoring allowed prompt intervention. No PTLD-related death was observed, all-cause mortality in the treated population was 68%.

CONCLUSIONS

Our PCR-guided and rituximab-based preemptive approach to avoid PTLD after allogeneic hematopoietic stem-cell transplantation is feasible but probably overtreated patients. Prospective trials are strongly needed, they should use uniform PCR techniques and consider higher threshold values for treatment initiation.

Associations of serum EBV DNA and gammopathy with post-transplant lymphoproliferative disease

BACKGROUND

Post-transplant lymphoproliferative disease (PTLD) is a life-threatening complication of immunosuppression following transplantation. Epstein-Barr virus (EBV) and gammopathy in serum are associated with PTLD, but these two parameters have not been evaluated in parallel for their association with PTLD.

METHODS

We evaluated the incidence of EBV load positivity, gammopathy, and protein expression in sera from all PTLD patients diagnosed at our hospital during the past seven yr. Results were compared with those of a control group including matched transplanted patients who did not develop PTLD.

RESULTS

Seven of 10 PTLD patients presented EBV(+) PTLD, for which five patients had detectable serum EBV DNA levels compared with none of 38 controls (RR between two groups =121, p < 0.0001). Five out of 10 patients had gammopathy at PTLD diagnosis compared with 5/38 controls (RR between two groups = 6.6, p = 0.022). Additionally, protein serum analysis by high-resolution two-dimensional gel electrophoresis and image examination failed to evidence specific abnormality in patients with PTLD compared with controls.

CONCLUSIONS

Our results confirm an association between EBV in sera and gammopathy with PTLD, and highlight the high specificity of the former analysis. Whether a combination of both analyses will improve the clinical detection of PTLD remains to be evaluated in a larger prospective cohort study.

Recent advancements for the evaluation of anti-viral activities of natural products

Significant progress has been achieved for the development of novel anti-viral drugs in the recent years. Large numbers of these newly developed drugs belong to three groups of compounds, nucleoside analogues, thymidine kinase-dependent nucleotide analogues and specific viral enzyme inhibitors. It has been found that the natural products, like plant extract, plant-derived compounds (phytochemicals) and so on, as well as traditional medicines, like Ayurvedic, traditional Chinese medicine (TCM), Chakma medicines and so on, are the potential sources for potential and novel anti-viral drugs based on different in vitro and in vivo approaches. In this chapter some of these important approaches utilised in the drug discovery process of potential candidate(s) for anti-viral agents are being discussed. The key conclusion is that natural products are one of the most important sources of novel anti-viral agents.

Simultaneous monitoring by real-time polymerase chain reaction of epstein-barr virus, human cytomegalovirus, and human herpesvirus-6 in juvenile and adult liver transplant recipients

Cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus-6 (HHV-6) cause symptomatic diseases in liver transplant recipients. The loads of these viruses, the associations between viral DNAemia, serologic status, and acute rejection reactions were investigated in a group of 17 juvenile and 17 adult recipients of living donor liver transplantation (LDLT) for a median of 8 weeks posttransplantation. At least 1 plasma sample from 15/34 (44.1%) patients was positive for CMV DNA. For most of the CMV-positive patients, the CMV DNA appeared in the second week of LDLT, and disappeared by the eighth week. A minimum of 200 EBV DNA copies/mug peripheral blood mononuclear cell DNA (defined as positive for EBV) was detected in 5/34 (14.7%) patients, and the number of EBV-positive children was significantly greater than the number of EBV-positive adults. In most of the EBV-positive patients, the EBV loads increased after 4 weeks posttransplantation. Plasma HHV-6 was detected in 7/34 (20.6%) patients. HHV-6 DNA appeared for a short period from the second week of LDLT. In addition, 8 of the 19 virus-positive recipients carried 2 viruses, with the combination of CMV and HHV-6 being the most frequent. Serologic status seemed to be an important factor for all 3 viral infections. The rate of acute cellular rejection was not significantly higher in the CMV-, EBV-, or HHV-6-positive groups. Simultaneous monitoring for 3 herpesviruses revealed the impact of these viruses on LDLT recipients.