Epstein-Barr Virus Load In Peripheral Blood Research Articles

Low incidence and morbidity of Epstein-Barr virus reactivation following donor lymphocyte infusions.

Low incidence and morbidity of Epstein-Barr virus reactivation following donor lymphocyte infusions.

Immunization with Epstein–Barr Virus Core Fusion Machinery Envelope Proteins Elicit High Titers of Neutralizing Activities and Protect Humanized Mice from Lethal Dose EBV Challenge

Epstein–Barr virus (EBV) is the primary cause of infectious mononucleosis and is strongly implicated in the etiology of multiple lymphoid and epithelial cancers. EBV core fusion machinery envelope proteins gH/gL and gB coordinately mediate EBV fusion and entry into its target cells, B lymphocytes and epithelial cells, suggesting these proteins could induce antibodies that prevent EBV infection. We previously reported that the immunization of rabbits with recombinant EBV gH/gL or trimeric gB each induced markedly higher serum EBV-neutralizing titers for B lymphocytes than that of the leading EBV vaccine candidate gp350. In this study, we demonstrated that immunization of rabbits with EBV core fusion machinery proteins induced high titer EBV neutralizing antibodies for both B lymphocytes and epithelial cells, and EBV gH/gL in combination with EBV trimeric gB elicited strong synergistic EBV neutralizing activities. Furthermore, the immune sera from rabbits immunized with EBV gH/gL or trimeric gB demonstrated strong passive immune protection of humanized mice from lethal dose EBV challenge, partially or completely prevented death respectively, and markedly decreased the EBV load in peripheral blood of humanized mice. These data strongly suggest the combination of EBV core fusion machinery envelope proteins gH/gL and trimeric gB is a promising EBV prophylactic vaccine.

Epstein-Barr Virus.

This review covers relevant clinical and laboratory information relating to Epstein-Barr virus (EBV) infections in immunocompromised hosts. It describes the epidemiology and clinical manifestations with a primary focus on disease in solid organ and stem cell transplant recipients. The review pays particular attention to diagnostic approaches, including serologic testing and imaging, with an expanded discussion on the role of measuring the EBV load in peripheral blood, identifying both strengths and limitations of this assay. Additional attention is paid to potential additional strategies of immunologic monitoring that may enhance the performance of EBV load monitoring.

MTOR inhibitors induce cell-cycle arrest and inhibit tumor growth in Epstein-Barr virus-associated T and natural killer cell lymphoma cells.

Epstein-Barr virus (EBV) infects B cells, as well as T cells and natural killer (NK) cells, and is associated with T or NK cell lymphoid malignancies. In various tumor cells, mTOR performs an essential function together with Akt with regard to cell growth. We investigated the effects of mTOR inhibitors on EBV-associated T- and NK-cell lymphomas. We investigated the Akt/mTOR activation pathway in EBV-positive and -negative T- and NK-cell lines (SNT13, SNT16, Jurkat, SNK6, KAI3, and KHYG1). We evaluated the antitumor effects of mTOR inhibitors (rapamycin and its analogue, CCI-779) against these cell lines in culture and in a murine xenograft model that was established by subcutaneous injection of SNK6 cells into NOG mice. All EBV-positive and -negative T- and NK-cell lines tested displayed activation of the Akt/mTOR pathway, and treatment with mTOR inhibitors suppressed mTOR activation. The inhibitors induced G1 cell-cycle arrest and inhibited cell proliferation in T- and NK-cell lines. Overall, T cell lines were more sensitive to rapamycin, but there were no significant differences between EBV-positive and -negative cell lines. Treatment with rapamycin did not affect lytic or latent EBV gene expression. Intraperitoneal treatment with CCI-779 significantly inhibited the growth of established tumors in NOG mice and reduced the EBV load in peripheral blood. These results suggest that inhibition of mTOR signaling is a promising new strategy for improving treatment of EBV-associated T- and NK-cell lymphoma.

Relationship between Non-Hodgkin’s lymphoma and blood levels of Epstein-Barr Virus in children in north-western Tanzania: a case control study

BackgroundNon-Hodgkin’s Lymphomas (NHL) are common in African children, with endemic Burkitt’s lymphoma (BL) being the most common subtype. While the role of Epstein-Barr Virus (EBV) in endemic BL is known, no data are available about clinical presentations of NHL subtypes and their relationship to Human Immunodeficiency Virus (HIV) infection and Epstein Barr Virus (EBV) load in peripheral blood of children in north-western, Tanzania.MethodsA matched case control study of NHL subtypes was performed in children under 15 years of age and their respective controls admitted to Bugando Medical Centre, Sengerema and Shirati district designated hospitals in north-western, Tanzania, between September 2010 and April 2011. Peripheral blood samples were collected on Whatman 903 filter papers and EBV DNA levels were estimated by multiplex real-time PCR. Clinical and laboratory data were collected using a structured data collection tool and analysed using chi-square, Fisher and Wilcoxon rank sum tests where appropriate. The association between NHL and detection of EBV in peripheral blood was assessed using conditional logistic regression model and presented as odds ratios (OR) and 95% confidence intervals (CI).ResultsA total of 35 NHL cases and 70 controls matched for age and sex were enrolled. Of NHLs, 32 had BL with equal distribution between jaw and abdominal tumour, 2 had large B cell lymphoma (DLBCL) and 1 had NHL-not otherwise specified (NHL-NOS). Central nervous system (CNS) presentation occurred only in 1 BL patient; 19 NHLs had stage I and II of disease. Only 1 NHL was found to be HIV-seropositive. Twenty-one of 35 (60%) NHL and 21 of 70 (30%) controls had detectable EBV in peripheral blood (OR = 4.77, 95% CI 1.71 – 13.33, p = 0.003). In addition, levels of EBV in blood were significantly higher in NHL cases than in controls (p = 0.024).ConclusionsBL is the most common childhood NHL subtype in north-western Tanzania. NHLs are not associated with HIV infection, but are strongly associated with EBV load in peripheral blood. The findings suggest that high levels of EBV in blood might have diagnostic and prognostic relevance in African children.

Epstein–Barr virus in autoimmune diseases

Autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and primary Sjögren's syndrome (pSS) are complex disorders with a genetic background and the involvement of environmental factors, including viruses. The Epstein-Barr virus (EBV) is a plausible candidate for playing a role in the pathophysiology of these diseases. Both SLE and RA are characterized by high titers of anti-EBV antibodies and impaired T-cell responses to EBV antigens. Compared with normal subjects, elevated EBV load in peripheral blood has been observed in SLE and RA. EBV DNA or RNA has been evidenced in target organs of RA (synovium) or pSS (salivary glands). Finally, molecular mimicry has been demonstrated between EBV proteins and self antigens in these three conditions. In addition, SLE, RA, and pSS are associated with an increased risk of lymphoma with a potential role for EBV. The influence of new and emergent treatments of these autoimmune diseases (biological therapies) on EBV load and the course of latent EBV infection requires further studies.

Immunizations and infectious diseases in pediatric liver transplantation

Liver transplantation (LTx) is an established and effective treatment for children with end-stage and metabolic liver disease. Improved surgical techniques and immunosuppressive regimens have led to enhanced short-term and long-term survival rates, which now approach or exceed 90%. Consequently, more children are being referred for LTx, and an increasing numbers of pediatric centers routinely perform this procedure. Infectious complications are an important cause of morbidity and mortality in children undergoing LTx. However, improvements in immune suppression management along with the availability of new antimicrobial agents and diagnostic tools have resulted in improved treatment and preventative regimens, thus reducing the impact of infectious complications on these children. This review provides an overview of the infectious complications and prevention strategies for children undergoing LTx.

Chronic herpesvirus reactivation occurs in aging

The aged immune system is characterized by clonal expansions of CD8+ T cells of which a substantial portion are directed against Epstein-Barr virus (EBV) and cytomegalovirus (CMV). It is unknown if these expansions represent increased viral reactivation or simply reflect an accumulation over time. We investigated herpesvirus reactivation in young and old subjects co-infected with CMV and EBV. Using molecular and serological techniques, we found significant increases in both the frequency and magnitude of EBV and CMV reactivation in elderly subjects. CMV DNA was frequently detected in the urine of elderly subjects; EBV load in peripheral blood was also significantly increased. Notably, EBV DNA in plasma was detected in a majority of the elderly subjects which was supported by frequent transcription of late structural genes. Furthermore, CD8+ T cells specific for EBV structural antigens were detected in samples from the elderly. Samples from our younger control group were negative for EBV DNA in plasma, CMV DNA in urine, expression of structural transcripts, and lacked CD8+ T cells specific for EBV structural antigens. These findings indicate that the aged immune system is no longer able to control EBV and CMV reactivation that could now be characterized as chronic instead of latent.

Characteristics of Epstein-Barr Virus-Associated Hemophagocytic Lymphohistiocytosis (HLH) in European Children.

Hemophagocytic lymphohistiocytosis (HLH) represents a severe sepsis-like disease with massive hypercytokinemia and with proliferating and organ-infiltrating phagocytes leading to cytopenia of different hematopoietic lineages. Besides primary familial cases of HLH, infections can cause secondary forms of HLH, among which Epstein-Barr virus (EBV) infections are the most frequent trigger. Between 2003 and 2005, 10 cases of EBV-associated HLH were analysed at a local subcenter of the international HLH study group. Serial blood samples from these 4 boys and 6 girls (age range: 2–14 years, median of age: 4 years) were examined for EBV load in peripheral blood mononuclear cells (PBMC) and plasma by real-time PCR analysis. EBV loads in both PBMC and plasma were significantly elevated in all HLH patients as compared with healthy controls and also with immunocompetent patients suffering from primary EBV infections. In one patient with excessively elevated EBV load in peripheral blood, analysis of EBV-DNA in separated T and B cells by real-time PCR showed an EBV infection of both cell types. During the course of disease, EBV load in HLH patients reflected the activity of disease. Regarding the clinical course and biochemical markers of disease such as LDH, ferritin or soluble IL2-receptor levels in plasma, patients with EBV-associated HLH did not differ from other patients with HLH. Conclusion: Measurement of EBV-load by real-time PCR facilitates detection of EBV-associated cases of HLH and monitoring of affected patients during the course of disease. EBV load analysis should become part of the initial routine examinations of newly diagnosed HLH patients in order to identify the frequency of EBV-associated forms of HLH. Without molecular diagnosis by means of EBV load measurement in peripheral blood, EBV-associated cases of HLH may be underdiagnosed in non-Asian populations.

Lymphoproliferation in children after liver transplantation.

Lymphoproliferation in children after liver transplantation.

Detection of Epstein–Barr virus EBER sequence in post-transplant lymphoma patients with DNA dendrimers

The EBER RNAs are the most numerous viral transcripts in latently infected lymphocytes in healthy individuals and also in the tumor cells of Epstein–Barr virus (EBV)-associated malignancies. A rise in EBV load in peripheral blood has been associated with the onset of post-transplant lymphoproliferative disease (PTLD) in immunocompromised patients. Treatment of PTLD with adoptive immunotherapy has made the rapid and accurate determination of EBV load essential. The relationship between EBV load and other EBV-associated malignancies, like Hodgkin's disease or AIDS-associated lymphoma, is unknown. In order to define viral load based on the number of EBV-infected cells in the peripheral blood, we developed a method which combines cellular dilution of peripheral blood mononuclear cells with the direct detection of EBER-1 RNA with DNA dendrimers. DNA dendrimers are large scaffolds of DNA which give at least a 500–1000-fold increase in detection of membrane bound nucleic acid over oilgonucleotide probes. The use of a novel class of these nucleic acid superstructures is described as a specific probe for EBER-1 detection. When two PTLD patients were analyzed for viral load with DNA dendrimers, at least one in 250 000 peripheral blood mononuclear cells were shown to be infected with EBV.

A prospective study in heart and lung transplant recipients correlating persistent Epstein-Barr virus infection with clinical events.

A 2-year prospective study was set up with 30 cardiothoracic transplant recipients to study Epstein-Barr virus (EBV) infection and immunity and their correlation with clinical events. Regression assays were used to measure EBV-specific cytotoxic T lymphocyte (CTL) function. Tissue culture, immunoblotting, and polymerase chain reaction were used for EBV detection and isolate variation studies. CTL activity was significantly lower in pretransplant seropositive patients than in healthy controls (P<0.001). CTL response was undetectable in all patients during the first 6 months after transplantation, but returned at levels significantly lower than pretransplant and control levels during the second posttransplant year (P<0.001). Return of CTL function was directly correlated with time of last treated rejection episode (P<0.003) and duration of high plasma levels of cyclosporine (over 400 ng/ml; P<0.003). Significantly higher levels of EBV were detected in peripheral blood during the first 6 months than in pretransplant or control samples (P<0.05). Excretion of EBV in throat washings was significantly lower during the first 3 months when all patients were receiving acyclovir than in pretransplant and control samples (P=0.02). An increase in virus shedding was noted 3-6 months after transplantation, which was significantly higher than in pretransplant patients and controls (P<0.05). Comparison of recipients' and donors' virus isolates in 11 cases showed that seropositive recipients retained their original EBV isolate and did not acquire the donor virus. Immunosuppression decreased EBV-specific host immune function, which in turn favored increased EBV load in peripheral blood and increased excretion in the oropharynx. The transfer of donor virus to the seropositive recipients was not observed.