Detection Of Epstein-Barr Virus DNA Research Articles

Epstein-Barr virus detected in a head and neck squamous cell carcinoma cell line derived from an immunocompromised patient.

DNA tumor viruses potentially play a role in the development of squamous cell carcinoma of the head and neck (SCCHN). Human papillomavirus is found in up to 50% of SCCHN specimens, and Epstein-Barr virus (EBV) has been detected in nasopharyngeal carcinoma, Burkitt lymphoma, and other lymphomas. However, the role of EBV in nonnasopharyngeal SCCHN has not been thoroughly investigated. Twenty-one SCCHN cell lines derived from tumors of various subsites were used to screen for EBV DNA as well as latent viral protein expression. The method of EBV DNA detection was polymerase chain reaction with 3 independent primer sets from distinct regions of the genome. Expression of the viral protein EBNA-1, critical for the maintenance of the viral episome, was monitored by immunofluorescence using an antibody specific for EBNA-1. In addition, 12 paraffin-embedded tumor specimens and adjacent normal tissues were analyzed by polymerase chain reaction. These tumor specimens were further characterized by immunohistochemistry with the use of a mouse monoclonal antibody that recognizes EBNA-1. Little or no EBV DNA was detected in 20 of 21 cell lines or in any of the tumor specimens, while detecting approximately 40 genome copies in a control reaction. Accordingly, these cell lines and specimens were negative for EBNA-1 expression. In 1 cell line derived from an immunosuppressed patient, EBV DNA was detected, and on further examination a small percentage of cells expressed EBNA-1 as shown by immunofluorescence. Although EBV may not be a major cofactor contributing to the proliferation of SCCHN, the limited initial evidence suggests that EBV may be involved in development of SCCHN in immunosuppressed patients.

Epstein-Barr virus DNA loads in adult human immunodeficiency virus type 1-infected patients receiving highly active antiretroviral therapy.

Patients with human immunodeficiency virus type 1 (HIV-1) infection are at high risk of developing Epstein-Barr virus (EBV)-associated lymphoma. However, little is known of the EBV DNA loads in patients receiving highly active antiretroviral therapy (HAART). Using a real-time quantitative polymerase chain reaction assay, we demonstrated that significantly more HIV-1-infected patients receiving HAART than HIV-1-uninfected volunteers had detectable EBV DNA in blood (57 [81%] of 70 vs. 11 [16%] of 68 patients; P=.001) and saliva (55 [79%] of 68 vs. 37 [54%] of 68 patients; P=.002). The mean EBV loads in blood and saliva samples were also higher in HIV-1-infected patients than in HIV-1-uninfected volunteers (P=.001). The frequency of EBV detection in blood was associated with lower CD4+ cell counts (P=.03) among HIV-1-infected individuals, although no differences were observed in the EBV DNA loads in blood or saliva samples in the HIV-1-infected group. Additional studies are needed to determine whether EBV-specific CD4+ and CD8+ cells play a role in the pathogenesis of EBV in HIV-1-infected patients receiving HAART.

Lack of evidence for an association of Epstein–Barr virus infection with breast carcinoma – authors' response

In her letter, recently published in Breast Cancer Research, Maria Victoria Preciado points out that some published evidence suggests a possible association of breast cancer with Epstein–Barr virus (EBV) [1]. EBV DNA has been detected by PCR in up to 50% of cases (for a review see [2]), and expression of the EBV-encoded nuclear antigen EBNA1 has been demonstrated in approximately 40% of cases by immunohistochemistry using the mAb designated 2B4 [3]. In combination, these findings seem to implicate EBV in the pathogenesis of breast carcinoma. Interestingly, however, most investigators agree that the EBV-encoded RNAs (EBERs), a hallmark of latent EBV infection, are not detectable in breast carcinoma tumour cells [2]. In two independent studies, we have analysed breast carcinomas for evidence of EBV infection [4,5]. In whole tissue sections, EBV DNA was detectable by quantitative PCR in up to 21% of cases at low copy number [5]. However, this does not allow conclusions regarding the cellular source of the viral DNA. We therefore attempted to detect viral DNA directly in the neoplastic cells using a sensitive DNA in situ hybridisation assay [4] or using quantitative PCR of microdissected tumour cells [5]. These studies yielded negative results [4,5]. In support of these results, in situ hybridisation for the detection of the EBERs was also negative in all cases while occasional EBV-positive non-neoplastic lymphocytes were detected by this approach [4]. The latter finding explains the detection of EBV DNA in whole tumour sections by PCR. There remains the issue of reactivity of breast carcinoma cells with the EBNA1-specific mAb 2B4. We have previously reported that this mAb yields nuclear labelling not only of EBV-infected cells, but also of some EBV-negative cells, notably epithelial cells [6]. We therefore recommended the use of another EBNA1-specific mAb, 1H4, when studying epithelial tumours [6]. In one of our recent studies, 31% of breast cancers, including cases that had tested negative for EBV genomes by PCR of microdissected tumour cells, showed nuclear labelling of tumour cells with the 2B4 mAb [5]. However, no labelling of tumour cells was observed with both mAbs in the other study [4]. The discrepancy between these results may relate to technical differences (e.g. fixation of tissues or antigen retrieval). We thus conclude that EBV is not present in tumour cells of breast carcinomas. The reactivity of tumour cell nuclei with the EBNA1-specific mAb 2B4 is likely to be the result of cross-reactivity with an unrelated epitope. There is currently no evidence that breast carcinoma is an EBV-associated malignancy.

Absence of epstein–barr virus DNA in the tumor cells of european hepatocellular carcinoma

The Epstein–Barr virus (EBV) has recently been associated with hepatocellular carcinoma (HCC) arising in Japanese patients. We analyzed 82 cases of HCC from Germany and the U.K. for the presence of EBV DNA and viral gene products within tumor cells. Initial screening of whole sections using quantitative (Q)-PCR detected EBV DNA in 9/58 U.K. cases and in 9/24 German cases; in positive cases viral load was very low, ranging between 1.4 and 49.1 copies of the EBV genome/1000 cell equivalents, compared to much higher values for EBV-positive Hodgkin’s disease and nasopharyngeal carcinoma controls (range, 714–3259/1000 cells). EBV DNA was not detected in the tumor cells of any of the Q-PCR-positive cases either by Q-PCR of pure tumor cell populations isolated by laser capture microdissection or by isotopic in situ hybridization. Furthermore, none of the German or U.K. HCC tumors tested positive for EBER or EBNAI expression in tumor cells. Our results provide strong evidence that HCCs from the U.K. or Germany are not associated with EBV.

Quantitative plasma/serum EBV DNA load by LMP2A determination in an Italian cohort of NPC patients.

Nasopharyngeal carcinoma (NPC) is frequently associated with Epstein-Barr virus (EBV), but little is known about the EBV DNA prevalence on peripheral blood in Western Countries, where the tumour is not endemic and its incidence is low. To set up and evaluate an internally controlled qualitative polymerase chain reaction (PCR) followed by quantitative competitive PCR for the detection of EBV DNA in clinical specimens. To investigate whether EBV DNA load in peripheral blood was a consistent feature of Italian NPC patients. A PCR assay based on latent membrane protein 2A (LMP2A) sequence amplification was chosen. Best assay conditions, sensitivity and reproducibility were determined. Sixty-four sera and 63 plasma from an Italian cohort of 39 NPC patients were analyzed. Samples from 5 patients followed up after radiotherapy were also assayed. Qualitative and quantitative beta-globin amplification was performed in parallel in order to provide an independent control for amplification competence of DNA and to investigate whether EBV DNA levels could be due to intracellular EBV viral genomes from cells lysed during plasma/serum collection. Twenty-five patients had undifferentiated carcinoma (UC) and 14 squamous cell carcinoma (SCC). EBV DNA has been quantified in 58 and 9% of the UC and SCC cases, respectively. No statistically significative differences were observed between the EBV DNA levels (469 vs 750 copies/ml, P=0.16) and prevalence (64 vs 57%, chi2(1)=0.22, P=0.64) in plasma and serum samples. Increased EBV viremia was found in patients with considerable extension of the primary tumour (172 vs 2250 copies/ml, low vs high tumour burden). Three UC subjects, which had detectable pre-treatment EBV DNA levels, became negative after radiotherapy. Clinical examination revealed that all had complete tumour regression. These PCR procedures allow an accurate and reproducible estimation of plasma/serum EBV DNA load in NPC patients living in non endemic areas, being strictly associated with UC WHO III and with tumour severity.

Epstein–Barr virus and human hepatocellular carcinoma

Recent studies suggest that Epstein–Barr virus (EBV) may act as a helper virus for the development of hepatocellular carcinoma by promoting replication of the hepatitis C virus (HCV) in the infected liver. Detection of EBV DNA in a high percentage of HCV-positive human hepatocellular carcinomas (HCC) from Japanese patients has supported this concept. In order to determine whether EBV infection is associated with HCC, we examined paraffin-embedded tissues from 31 cases of non-cirrhotic livers with hepatocellular carcinoma for the presence of EBV, HCV and hepatitis B virus (HBV) infection. RNA prepared from tumor samples were used as a template for reverse transcription followed by double-nested PCR with primers for the 5′ untranslated region (NT) of HCV. DNA extracts of tumor samples were tested by single polymerase chain reaction for the detection of EBV and HBV (X- and/or S-gene) DNA sequences. To control for nucleic acid integrity, all tumor samples were amplified for human β-globin DNA by polymerase chain reaction and subjected to Southern blot hybridization. None of the cases was found to be positive for EBV. Ten HCC cases (32%) tested positive for HCV and 12 HCC cases (38%) tested positive for HBV. Six of the surveyed patients had nucleic acids of both HCV and HBV in their tumor tissue. All HCC tumor samples were positive for β-globin. Our study shows that HCV and HBV infections, but not EBV infection, are associated with hepatocarcinogenesis in non-cirrhotic livers. Other unknown risk factors seem to be in effect in the development of hepatocellular carcinoma in non-cirrhotic livers.

Interferon-gamma secretion and perforin expression are impaired in CD8+ T lymphocytes from patients with undifferentiated carcinoma of nasopharyngeal type.

An efficent antitumor and antiviral cellular immune response requires optimal interferon-gamma (IFN-gamma) secretion and perforin expression in CD8(+) T cells. The aim of this study was to define whether CD4(+) and CD8(+) T cells from patients with undifferentiated carcinoma of nasopharyngeal type (UCNT), a tumor regularly associated with the Epstein-Barr virus (EBV), have abnormal phenotype profiles, cytokine production, perforin and CD3-zeta expressions. Our data showed that CD4 and CD8 subset distribution was not grossly altered in the peripheral blood of UCNT patients, while tumor biopsies contained an increased proportion of CD8(+) T cells. The analysis of the CD4(+) subset showed a defect in interleukin-2 (IL-2) production and a moderate increase of IL-10 production, a situation consistent with a Th1/Th2 imbalance. We have also demonstrated that CD8(+) lymphocytes from UCNT patients had a marked impairment of IFN-gamma secretion and perforin expression. This impairment was not related to the presence of detectable EBV DNA in the plasma. In UCNT patients, the blockade of the perforin pathway and of IFN-gamma production may constitute important mechanisms for immune escape by the tumor and for impaired control of EBV replication.

Epstein-Barr virus DNA and epithelial markers in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) belongs to the most common malignant tumours in certain parts of the world, e.g. South-East Asia. The undifferentiated type of NPC is associated with genomic Epstein-Barr virus (EBV) DNA. In normal epithelia of the nasopharynx cytokeratins (CK) 4, 5, 6, 13, 14, 15 and 19 are expressed. The aim of this study was to analyse the expression pattern of cytokeratins in NPC in the presence of EBV infection. Twenty primary or metastatic tumours from 13 patients suffering from a NPC were evaluated (formalin-fixed, paraffin-embedded). (35)S-labelled probes were used to detect EBV DNA in the tissue sections. Fourteen specimens (70%) were EBV positive. All positive specimens were undifferentiated NPC. All NPC were identified with broad-spectrum anti-CK antibody. Using a panel of anti-CK antibodies, there was no specific CK-expression pattern in NPC. In summary, undifferentiated NPC are strongly associated with EBV. The cytoskeleton of undifferentiated NPC reveals no specific pattern of CK expression.

Quantitative CSF PCR in Epstein-Barr virus infections of the central nervous system.

Acute Epstein-Barr virus (EBV) infection of the central nervous system (CNS) is associated with meningoencephalitis and other neurological syndromes and with CNS lymphomas (CNSLs). Diagnosis is based on serological studies and more recently on detection of EBV DNA in cerebrospinal fluid (CSF) by polymerase chain reaction (PCR). We measured EBV DNA by quantitative PCR and EBV mRNA by RT-PCR in the CSF in patients with EBV-associated neurological disorders. EBV was identified as the cause of CNS infection in 28 patients: 14 with CNSL, 10 with encephalitis, and 4 with postinfectious neurological complications. CSF analysis showed that patients with CNSL had high EBV load (mean +/- standard error of 4.8 +/- 0.2 log(10) DNA copies/ml) and low leukocyte counts (22 +/- 7 cells/microl); encephalitis was characterized by high EBV load (4.2 +/- 0.3 log(10) DNA copies/ml) and high leukocyte counts (143 +/- 62 cells/microl); and patients with postinfectious complications showed low EBV load (3.0 +/- 0.2 log(10) DNA copies/ml) with high leukocyte counts (88 +/- 57 cells/microl). Lytic cycle EBV mRNA, a marker of viral replication, was identified in 10 CSF samples from patients with CNSL and encephalitis. These studies demonstrate the utility of quantitative CSF PCR and establish the presence of lytic cycle EBV mRNA in CSF of patients with EBV-associated neurological disease.

Epstein-Barr virus and human immunodeficiency virus serological responses and viral burdens in HIV-infected patients treated with HAART.

Epstein-Barr virus (EBV) associated non-Hodgkin lymphoma is recognized as a complication of human immunodeficiency virus (HIV) infection. Little is known regarding the influence of highly active antiretroviral therapy (HAART) on the biology of EBV in this population. To characterize the EBV- and HIV-specific serological responses together with EBV DNA levels in a cohort of HIV-infected adults treated with HAART, a study was conducted to compare EBV and HIV serologies and EBV DNA copy number (DNAemia) over a 12-month period after the commencement of HAART. All patients were seropositive for EBV at baseline. Approximately 50% of patients had detectable EBV DNA at baseline, and 27/30 had detectable EBV DNA at some point over the follow-up period of 1 year. Changes in EBV DNA copy number over time for any individual were unpredictable. Significant increases in the levels of Epstein-Barr nuclear antigen (EBNA) and Epstein-Barr early antigen (EA) antibodies were demonstrated in the 17 patients who had a good response to HAART. Of 29 patients with paired samples tested, four-fold or greater increases in titers were detected for EA in 12/29 (41%), for EBNA in 7/29 (24%), for VCA-IgG in 4/29 (14%); four-fold decreases in titers were detected in 2/29 (7%) for EA and 12/29 (41%) for EBNA. A significant decline in the titer of anti-HIV antibodies was also demonstrated. It was concluded that patients with advanced HIV infection who respond to HAART have an increase in their EBV specific antibodies and a decrease in their HIV-specific antibodies. For the cohort overall, there was a transient increase in EBV DNA levels that had declined by 12 months.

Detection of cell free Epstein-Barr virus DNA in sera from patients with nasopharyngeal carcinoma.

The detection of tumor-derived DNA within the circulation of patients with malignant disease using polymerase chain reaction (PCR)-based strategies has opened a new avenue for the diagnosis and monitoring of these patients. Because of the universal association of Epstein-Barr virus (EBV) with the nonsquamous type of nasopharyngeal carcinoma (NPC; World Health Organization types II and III), the detection of cell free EBV DNA in sera from patients with NPC may be a valuable tool for monitoring the progress of tumors or to provide advanced warning of tumor recurrence. Serum samples were obtained from different patients, and cell free EBV DNA was detected with a conventional PCR approach. A total of 134 patients were sampled, including 36 patients with primary NPC, 28 control patients, 18 patients suffering from locoregional recurrence, 7 patients with distant metastasis, and 45 patients with NPC in clinical remission. A conventional PCR approach employing standard 35-cycle and 50-cycle reactions was used to detect cell free EBV genomes. Results from the two PCR cycles were compared to provide a semiquantitative picture of the relative quantity of EBV genome in each serum sample. The EBV DNA detection rates, i.e., the rates of positive detection, for 35-cycle and 50-cycle PCR analyses, respectively, were 38.9% and 75% for patients with primary NPC, 3.5% and 10.7% for control patients, 27.8% and 88.9% for patients with locoregional disease recurrence, 71.4% and 100% for patients with distant metastasis, and 7.1% and 36.5% for patients with disease in clinical remission. The rates of positive detection among patients with active disease all appeared to be significantly greater compared with the rates among patients with disease in clinical remission. Longitudinal data for six patients with recurrent tumors revealed a close correlation between the relative quantity of circulating cell free EBV genomes and the disease course of these patients. The sensitivity, specificity, positive predictive value, and negative predictive value of the 50-cycle PCR analysis for detecting recurrent disease were 92%, 63.5%, 42.6%, and 96.4%, respectively. This study demonstrated that, by using a 50-cycle PCR-based approach, high sensitivity and high negative predictive value for detecting recurrent disease can be obtained from the detection of the cell free EBV genome in sera from patients with NPC. The 50-cycle PCR analysis, therefore, may provide a simple, clinically useful adjuvant method for monitoring patients with NPC.

Analytic validation of a competitive polymerase chain reaction assay for measuring Epstein-Barr viral load.

Epstein-Barr virus (EBV) is associated with several benign and malignant diseases, and blood tests for EBV viral load show promise as markers of disease burden in affected patients. A commercial quantitative PCR method (BioSource International) was recently introduced to facilitate measuring viral load. It relies on coamplification of EBV DNA and a spiked competitor in plasma or serum, followed by semiautomated product detection on enzyme-linked immunosorbent assay (ELISA) plates. In the current study, analytic performance characteristics were assessed, and the authors describe several methodologic improvements to facilitate laboratory implementation. Rapid DNA extraction was accomplished using commercial silica spin columns, heat-labile uracil-N-glycosylase was used to inhibit amplicon contamination, and inexpensive agarose gels were used to screen for polymerase chain reaction products requiring ELISA plate quantitation. Accuracy and precision were verified using EBV DNA standards derived from two cell lines and plasmid containing viral sequences. The assay was sensitive to as few as five template copies per polymerase chain reaction and was linear across four orders of magnitude (correlation coefficient 0.995). When applied to matched plasma and serum samples from 15 patients with nasopharyngeal carcinoma, both sample types yielded similar viral load results. This commercial EBV viral load assay provides sensitive and quantitative detection of EBV DNA using equipment already available in many molecular diagnostic laboratories.

Detection of Epstein–Barr virus DNA in peripheral blood of paediatric patients with Hodgkin's disease by real-time polymerase chain reaction

Hodgkin's disease (HD) is commonly associated with latent Epstein–Barr virus (EBV) infection. The aim of our study was a detailed molecular analysis of the EBV status in the peripheral blood of paediatric patients with HD. Blood samples from HD patients were examined before (n=28) and after treatment (n=12). The control group consisted of 20 healthy children and 10 immunosuppressed children with primary EBV infection. EBV load in plasma and peripheral blood mononuclear cells (PBMC) were determined by real time quantitative polymerase chain reaction (RQ-PCR) as recently described. Before treatment, EBV DNA was detected in the plasma of 13/24 EBV-seropositive HD patients, whereas in plasma of healthy controls no EBV DNA was detectable (P<0.001). After treatment, no EBV genomes were found in the plasma of 6 HD patients in stable and complete remission. In contrast, 2/5 HD patients with relapse of disease were positive for EBV DNA in the plasma. In PBMCs, no differences were found in EBV load measured in HD patients before or after treatment and healthy controls. A high EBV load was found in both the plasma and PBMCs of all immunosuppressed patients with primary EBV infection. Thus, EBV DNA detection in the plasma of paediatric HD patients might be of value for non-invasive diagnostic, prognostic and follow-up tests for HD.

Circulating Cell‐Free Epstein‐Barr Virus DNA Levels in Patients with EBV‐Associated Lymphoid Malignancies

Epstein-Barr virus (EBV) is a human lymphotrophic herpesvirus implicated in the development of several lymphoid malignancies. Recently, detection of cell-free EBV DNA in sera or plasma from patients with EBV-associated malignancies has been reported. However, most published studies are qualitative in nature, with only a few providing quantitative data. We have described the temporal changes of plasma EBV DNA levels in patients with EBV-associated lymphoid malignancies during therapy using quantitative real-time PCR. A close correlation between plasma EBV DNA levels and therapeutic response was observed. Our aim was to update our results and to assess the role of the plasma EBV DNA levels as a molecular marker for disease monitoring in patients with EBV-associated lymphoid malignancies.

Dynamics of Epstein‐Barr virus DNA levels in serum during EBV‐associated disease

A real-time polymerase chain reaction assay for quantitation of Epstein-Barr virus (EBV) DNA in serum was developed. This assay detected EBV DNA in 24 (89%) of 27 sera from patients with infectious mononucleosis, but only in 9 (18%) of 51 sera from EBV carriers (P < 0.001) and in none of the sera from 32 EBV-seronegative individuals. EBV DNA levels were higher in sera from infectious mononucleosis (median 8,000, range 1833-150,069 copies/ml) than from carriers (median < 2, range < 2-2980; P < 0.001). In sera of 36 children with infectious mononucleosis followed prospectively, EBV DNA levels correlated inversely with the duration of symptoms. Among 18 children with tumors including Hodgkin's disease (n = 7), non-Hodgkin's lymphoma (n = 6), Burkitt's lymphoma (n = 1), lymphoproliferative disorder (n = 4), and osteosarcoma (n = 1), EBV DNA was detected in serum from those 9 (100%) expressing EBV in the tumor (Hodgkin's disease, 3; non-Hodgkin's lymphoma, 2; lymphoproliferative disorder, 4), the levels peaking at diagnosis and correlating with disease activity. Quantitation of EBV DNA in serum may offer a simple means of monitoring patients at risk of EBV-associated lymphoproliferation.

Quantitative analysis of circulating cell-free Epstein-Barr virus (EBV) DNA levels in patients with EBV-associated lymphoid malignancies.

Cell-free Epstein-Barr virus (EBV) DNA has recently been detected in the plasma and serum of patients with Hodgkin's disease, post-transplant lymphoproliferative disease (PTLD) and acquired immunodeficiency syndrome-related lymphoma. However, no data are available on the temporal variation of plasma/serum EBV DNA levels in patients with EBV-associated lymphoid malignancies during the course of therapy. Using a real-time quantitative polymerase chain reaction assay, we studied the plasma EBV DNA levels in 13 patients with EBV-associated lymphoid malignancies (six patients with Hodgkin's disease, four with nasal natural killer/T-cell lymphoma, two cases of PTLD and one patient with Burkitt's lymphoma) at presentation and during therapy. Plasma EBV DNA was detected in 12 of the 13 patients (median 2,266 copies/ml; interquartile range 181-8,379 copies/ml), but not in any of 35 healthy control subjects (P < 0.0001). The EBV status in tumour cells was also examined in 12 of these patients using in situ hybridization for EBV-encoded small RNAs (EBERs). EBER positivity was observed in 11 patients, all of whom had EBV DNA detectable in plasma. The one patient who had no detectable plasma EBV DNA was also negative for EBERs in tumour tissue. Serial measurements of plasma EBV DNA levels were performed in nine of the patients during the course of therapy. All patients who responded to therapy demonstrated a significant reduction of plasma EBV DNA to low or undetectable levels, whereas in two patients with ineffective therapy, disease progression was associated with a rapid increase in plasma EBV DNA levels. We concluded that plasma EBV DNA is detectable in a wide range of EBV-associated lymphoid malignancies. As plasma EBV DNA levels correlate well with the therapeutic response, such analysis may be a valuable tool for monitoring clinical progress.

Association between clinical disease activity and Epstein-Barr virus reactivation in MS.

To assess the potential significance of Epstein-Barr virus (EBV) reactivation in disease activity in MS patients. The prevalence of antibodies against herpes simplex virus type 1 (HSV-1), HSV-2, EBV, and cytomegalovirus was determined in a group of 108 MS patients and in 163 healthy control subjects. Sera were analyzed using combinations of novel assay systems employing highly purified viral and recombinant antigens. In addition, PCR for the detection of EBV DNA was performed in serial samples. In contrast to the control populations, antibodies against EBV were present in 100% of MS patients. Among the tested human herpesviruses, this high extent of seropositivity was only found for EBV. Primary infection was found exclusively in the control group (3.7%), whereas serologic evidence of EBV reactivation was seen in MS patients (13. 9%) as well as control subjects (17.2%). There was no temporal coincidence between EBV reactivation and disease activity in MS patients. However, in 19 patients followed monthly for 1 year, active viral replication as measured by increased immunoglobulin (Ig) M and IgA responses to EBV early antigens (p54 + p138) and positive serum DNA was seen in 72.7% of patients with exacerbations during the study period and in none of the patients with clinically stable disease. The results demonstrate an association between EBV reactivation and disease activity in MS patients over time, and suggest that EBV might play an indirect role in MS as an activator of the underlying disease process.

Epstein-Barr virus reactivation associated with diminished cell-mediated immunity in antarctic expeditioners.

Epstein-Barr virus (EBV) reactivation and cell-mediated immune (CMI) responses were followed in 16 Antarctic expeditioners during winter-over isolation at 2 Australian National Antarctic Research Expedition stations. Delayed-type hypersensitivity (DTH) skin testing was used as an indicator of the CMI response, that was evaluated 2 times before winter isolation and 3 times during isolation. At all 5 evaluation times, 8 or more of the 16 subjects had a diminished CMI response. Diminished DTH was observed on every test occasion in 4/16 subjects; only 2/16 subjects exhibited normal DTH responses for all 5 tests. A polymerase chain reaction (PCR) assay was used to detect EBV DNA in saliva specimens collected before, during, and after the winter isolation. EBV DNA was present in 17% (111/642) of the saliva specimens; all 16 subjects shed EBV in their saliva on at least 1 occasion. The probability of EBV shedding increased (P = 0.013) from 6% before or after winter isolation to 13% during the winter period. EBV appeared in saliva during the winter isolation more frequently (P < 0.0005) when DTH response was diminished than when DTH was normal. The findings indicate that the psychosocial, physical, and other stresses associated with working and living in physical isolation during the Antarctic winter result in diminished CMI and an accompanying increased reactivation and shedding of latent viruses.

A simple and rapid technique for the detection of Epstein-Barr virus DNA in HIV-associated oral hairy leukoplakia biopsies.

A method of generating nucleic acid probes by polymerase chain reaction (PCR) for the detection of Epstein-Barr virus (EBV)-DNA by in situ hybridization in oral hairy leukoplakia (OHL) lesions is described. This method has the advantage over older methods of being cheaper, quicker and retaining sensitivity and specificity. Purified PCR products of Epstein-Barr virus DNA of 110 bp and 328 bp were labelled with biotin by nick translation or random primer labelling and were compared in in situ hybridization experiments with probes prepared by incorporation of biotin-labelled nucleotides in the PCR reaction mixture, with EBV viral DNA as a template. These probes were applied to 18 OHL tongue biopsies known to be positive for EBV-DNA, using a commercially available biotin-labelled BamHI "V" fragment EBV-DNA probe. To determine the specificity of the probes, we applied them to 20 normal tongue tissue samples and to 12 biopsies taken from keratotic tongue lesions from patients without risk factors for HIV infection and known to be negative for EBV-DNA. Clear positive signals for EBV-DNA were detected in all 18 cases of OHL biopsies using the amplimer of 328 bp labelled by PCR and random primer labelling. However, nick translation labelling was less efficient and sensitive. All control specimens were negative for EBV-DNA.

Development of a real-time quantitative assay for detection of Epstein-Barr virus.

With the use of real-time PCR, we developed and evaluated a rapid, sensitive, specific, and reproducible method for the detection of Epstein-Barr virus (EBV) DNA in plasma samples. This method allowed us to screen plasma and serum samples over a range between 100 and 10(7) copies of DNA per ml using two sample preparation methods based on absorption. A precision study yielded an average coefficient of variation for both methods of less than 12%, with a coefficient of regression for the standard curve of a minimum of 0. 98. We detected EBV DNA in 19.2% of plasma samples from immunosuppressed solid-organ transplant patients without symptoms of EBV infections with a mean load of 440 copies per ml. EBV DNA could be detected in all transplant patients diagnosed with posttransplant lymphoproliferative disorder, with a mean load of 544,570 copies per ml. No EBV DNA could be detected in healthy individuals in nonimmunosuppressed control groups and a mean of 6,400 copies per ml could be detected in patients with infectious mononucleosis. Further studies revealed that the inhibitory effect of heparinized plasma could be efficiently removed by use of an extraction method with Celite as the absorbent.