Frequent Epstein-Barr Virus Research Articles

Clinicopathological characteristics and lymph node metastasis rates in early gastric lymphoepithelioma-like carcinoma: Implications for endoscopic resection.

321 Background: We aimed to clarify the clinicopathological features and the rate of lymph node metastases (LNM) of early gastric lymphoepithelioma-like carcinoma (LELC). Methods: We compared the clinicopathological characteristics of 82 LELC and 5758 well- or moderately differentiated (WD or MD) tubular adenocarcinoma patients who received gastrectomy for single early gastric cancer (EGC). Results: Compared to the control group, early LELC patients were younger, had a higher prevalence of proximally located tumors, more frequent Epstein-Barr virus (EBV) infection, more frequent deep submucosal invasion (SM2 or SM3, 85.4% versus 29.9%, P < 0.001) but less frequent lymphatic invasion (4.9% versus 16.2%, P = 0.009). Among tumors with deep submucosal invasion, early LELC patients had smaller tumor sizes, less frequent lymphatic invasion (5.7% versus 40.1%, P < 0.001) and a lower rate of LNM (7.1% versus 19.4%, P = 0.016) than the control group. LNM rates of LELC patients with mucosal, shallow submucosal invasion (SM1) and deep submucosal invasion were 0%, 0%, and 7.1%, respectively. Lymphatic invasion was the only significant risk factor in the regression analysis for LNM in LELC patients. Among 12 patients with mucosal or shallow submucosal invasion and 27 patients with deep submucosal invasion having small tumor sizes (less than 2 cm) and no lymphatic invasion, there was no LNM. Conclusions: Given the low rate of LNM, the same curability criteria of ESD for WD or MD EGC may be applied to early LELC and even more flexibly for those considered non-curative ESD only because of deep submucosal invasion.

Pulmonary squamous cell carcinoma and lymphoepithelial carcinoma - morphology, molecular characteristics and differential diagnosis.

Squamous cell carcinoma (SCC) comprises one of the major groups of non-small-cell carcinoma of the lung, and is subtyped into keratinising, non-keratinising and basaloid SCC. SCC can readily be diagnosed using histomorphology alone in keratinising SCC. Confirmatory immunohistochemical analyses should always be applied in non-keratinising and basaloid tumours to exclude differential diagnoses, most prominently adenocarcinoma and high-grade neuroendocrine carcinoma, which may have important therapeutic consequences. According to the World Health Organisation (WHO) classification 2015, the diagnosis of SCC can be rendered in resections of morphologically ambiguous tumours with squamous immunophenotype. In biopsies and cytology preparations in the same setting thecurrent guidelines propose a diagnosis of 'non-small-cell carcinoma, favour SCC' in TTF1-negative and p40-positive tumours to acknowledge a possible sampling bias and restrict extended immunohistochemical evaluation in order to preserve tissue formolecular testing. Most SCC feature a molecular 'tobacco-smoke signature' with enrichment in GG > TTmutations, in line with the strong epidemiological association of SCC with smoking. Targetable mutations are extremely rare but they do occur, in particular in younger and non- or light-smoking patients, warranting molecular investigations. Lymphoepithelial carcinoma (LEC) is a poorly differentiated SCC with a syncytial growth pattern and a usually prominent lymphoplasmacytic infiltrate and frequent Epstein-Barr virus (EBV) association. In this review, we describe the morphological and molecular characteristics of SCC and LEC and discuss the most pertinent differential diagnoses.

EBV-IgA antibody responses in endemic and nonendemic populations with nasopharyngeal carcinoma: tumour marker prognostication study and a cross-sectional study.

Nasopharyngeal carcinoma (NPC) is the most prevalent head and neck cancer in Indonesia, with 100% Epstein-Barr virus (EBV) infection in tumor cells. NPC is rare in the Netherlands. The involvement of EBV in NPC pathogenesis is reflected by early onset aberrant IgA antibody responses to various EBV proteins. Screening for elevated EBV-IgA levels is proposed for NPC risk assessment in endemic countries but is poorly studied in nonendemic regions. This study analyzed the overall diversity (immunoblot) as well as the prevalence and normalized levels of IgA responses to immunodominant peptide epitopes of EBV proteins VCA P18, EBNA 1, and Zebra (Zta) (N-terminus, P 125, P 130, full-length recombinant Zebra) in Indonesian (n=50) and Dutch (n=50) patients with NPC. The results confirmed that elevated levels of IgA-VCA P18 and IgA-EBNA 1 were found in both NPC populations, but that IgA-Zta was more variable. IgA-Zta responses were more pronounced in Indonesian NPC cases, reflecting more frequent EBV reactivation overall. IgA-VCA P18 and IgA-EBNA are independent tumor markers and are both necessary for NPC risk assessment. Overall, these results confirmed the diagnostic benefit of combined IgA-VCA P18/-EBNA 1 testing for NPC risk assessment in endemic and nonendemic populations.

Взаимодействие вируса Эпштейна — Барр и вируса папилломы человека в канцерогенезе шейки матки. Возможности профилактики

Objective of the Review: To comprehensively analyse the potential role of Epstein-Barr virus (EBV) in development of cervical cancer. Key Points. Human papilloma virus (HPV) is a key causative factor of cervical cancer. However, there are a lot of data collected over the last two decades demonstrating that EBV has a role to play in this process; still, its contribution to development of cervical cancer has been studied poorly. This review describes the real-time published data on EBV and HPV co-infection in the genesis of cervical cancer, and the potential role of EBV in gynaecological cancer progression. Conclusion. EBV has an important role in the genesis and progression of some human malignancies including lymphoid tumours (both В- and Т-cell cancer) and carcinoma (nasopharyngeal and gastric cancer). The available data are indicative of potential cause-effect relations between EBV and cervical cancer pathogenesis. A frequent EBV and HPV co-infection in cervical cancer witnesses possible cancer-causing interaction between the two viruses. Thus, more in-depth studies are needed to find out the mechanisms underlying the EBV and HPV synergism and its clinical effects. Taking into account successful cervical cancer prevention with HPV vaccine and possible future EBV vaccination, the carcinogenesis mechanisms should be studied more thoroughly in order to improve the prevention of oncological diseases. Keywords: oncology, Epstein-Barr virus, human papilloma virus, co-infection, cervical cancer.

Risk factors for Epstein-Barr virus reactivation after renal transplantation: Results of a large, multi-centre study.

Epstein-Barr virus (EBV) reactivation is a very common and potentially lethal complication of renal transplantation. However, its risk factors and effects on transplant outcome are not well known. Here, we have analysed a large, multi-centre cohort (N=512) in which 18.4% of the patients experienced EBV reactivation during the first post-transplant year. The patients were characterized pre-transplant and two weeks post-transplant by a multi-level biomarker panel. EBV reactivation was episodic for most patients, only 12 patients showed prolonged viraemia for over four months. Pre-transplant EBV shedding and male sex were associated with significantly increased incidence of post-transplant EBV reactivation. Importantly, we also identified a significant association of post-transplant EBV with acute rejection and with decreased haemoglobin levels. No further severe complications associated with EBV, either episodic or chronic, could be detected. Our data suggest that despite relatively frequent EBV reactivation, it had no association with serious complications during the first post-transplantation year. EBV shedding prior to transplantation could be employed as biomarkers for personalized immunosuppressive therapy. In summary, our results support the employed immunosuppressive regimes as relatively safe with regard to EBV. However, long-term studies are paramount to support these conclusions.

Examining the dynamics of Epstein-Barr virus shedding in the tonsils and the impact of HIV-1 coinfection on daily saliva viral loads.

Epstein-Barr virus (EBV) is transmitted by saliva and is a major cause of cancer, particularly in people living with HIV/AIDS. Here, we describe the frequency and quantity of EBV detection in the saliva of Ugandan adults with and without HIV-1 infection and use these data to develop a novel mathematical model of EBV infection in the tonsils. Eligible cohort participants were not taking antiviral medications, and those with HIV-1 infection had a CD4 count >200 cells/mm3. Over a 4-week period, participants provided daily oral swabs that we analysed for the presence and quantity of EBV. Compared with HIV-1 uninfected participants, HIV-1 coinfected participants had an increased risk of EBV detection in their saliva (IRR = 1.27, 95% CI = 1.10-1.47) and higher viral loads in positive samples. We used these data to develop a stochastic, mechanistic mathematical model that describes the dynamics of EBV, infected cells, and immune response within the tonsillar epithelium to analyse potential factors that may cause EBV infection to be more severe in HIV-1 coinfected participants. The model, fit using Approximate Bayesian Computation, showed high fidelity to daily oral shedding data and matched key summary statistics. When evaluating how model parameters differed among participants with and without HIV-1 coinfection, results suggest HIV-1 coinfected individuals have higher rates of B cell reactivation, which can seed new infection in the tonsils and lower rates of an EBV-specific immune response. Subsequently, both these traits may explain higher and more frequent EBV detection in the saliva of HIV-1 coinfected individuals.

High Incidence but Very Low Mortality of Epstein Barr Virus Related Post-Transplantation Lymphoproliferative Disorder after T-Cell Replete Haploidentical Peripheral Blood Stem Cell Transplantation

BACKGROUNDThe use of immunosuppressive agents such as antithymocyte globulin (ATG) as graft-versus host disease (GVHD) prophylaxis may increase the risk of Epstein Barr Virus (EBV) related post-transplant lymphoproliferative disorder (PTLD). The aim of the present study is to report the incidence, risk factors, and outcome of PTLD in the setting of haploidentical stem cell transplant (haploSCT) combining PTCy and ATG as GVHD prophylaxis.METHODSFrom August 2016 to May 2018, 55 adult patients diagnosed with hematological malignancies underwent T-cell replete haploSCT. All patients received a reduced intensity conditioning regimen (RIC) with fludarabine, busulfan, and 200cGy of total body irradiation (TBI), combined with rabbit ATG, PTCy and cyclosporine (Cy).EBV titre was monitored by quantitative PCR in plasma samples. The cut-off value for test positivity was >600 copies of EBV DNA per milliliter of plasma. Testing was performed weekly from engraftment to day 100 and beyond in case the patients were on immunosuppression.Data was collected through retrospective chart review. Last follow up was updated in June 31, 2018. Median follow-up was 9.5 months (range 1-21).RESULTSPatient and donor characteristics are summarized in Table 1. Median age was 57 (22-73) years, with 23 (43%) patients ≥60 years. Overall survival of the 55 patients at 6 months was 70% (95% CI 57-83), and 51% (95% CI 46-66) at 1 year.EBV reactivation was documented in 31 (57%) patients. Median time to EBV reactivation was 54 (20-326) days. Three (5.5%) patients developed presumed PTLD with EBV-viremia higher than 1x10E6 copies and corroborative imaging. Three (5.5%) had biopsy-proven PTLD (Table 2). Median time since EBV reactivation to presumed/proven (P/P)-PTLD was 25 (3-36) days. All cases occurred early post-transplant within the first 100 days. Four patients were on therapeutic doses of cyclosporine. All 6 (11%) patients received treatment with weekly Rituximab 375 mg/m+. Five (83%) patients achieved complete clinical responses with PCR negativity with reduction of immunosuppression and single agent rituximab. One patient died of complications of viral encephalitis and bacterial pneumonia.CONCLUSIONATG based conditioning can be associated with increased viral reactivations. Frequent EBV monitoring and pre-emptive treatment may lead to rapid disease control. While no guidelines exist currently, further investigation is needed to define optimal monitoring strategies. [Display omitted] DisclosuresLipton:BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding.

Unexpected Higher Tacrolimus Levels at the Onset of Epstein-Barr Virus Associated Post-Transplantation Lymphoproliferative Disorder in Living Donor Liver Transplant Infants

Introduction: Post-transplantation lymphoproliferative disorder (PTLD) is a life threatening disease, which occurs as high as 20% of liver transplanted children. Especially, liver transplanted infants are high risk group of Epstein-Barr virus (EBV) associated PTLD because of their immature immunity and primary EBV transmission from EBV positive graft implantation. In this study, we investigated relationship between changes of tacrolimus (Tac) trough levels and symptomatic infectious episodes associated with EBV. Patients and methods: From July 1991 to June 2011, 85 pediatric living donor liver transplantations (LDLT) were performed at Tohoku University Hospital. Of these patients, there were 32 infants, who received Tac and steroids as a primary induction therapy, with an age of less than 2 years old at LDLT. In this study, a retrospective review of the transplant records of these 32 patients was conducted. The indication for LDLT included biliary atresia (n=31) and fulminant hepatitis (n=1). 32 infants were all survived for over 1-year. The definition of PTLD was infectious episodes with peripheral-blood mononuclear cells and/or serum EBV DNA positivity (cut-off value>102.5 copies/μg DNA) and with persisting abnormal nodal swelling with/without extranodal findings confirmed by contrast enhanced computed tomography images. Results: 21 (66%) of 32 patients experienced symptomatic viral infection. 8 (25%) of these patients were EBV seronegative at the onset of viral infectious episode. Of the remaining 13 patients, 8 (25%) experienced infectious episodes with sudden positive change of blood EBV DNA load without the development of PTLD at a median of 358 (161-580) posttransplant days (non-PTLD group). 5 (16%) patients developed PTLD at a median of 198 (112-447) posttransplant days (PTLD group). All 13 patients resolved their symptoms and signs associated with EBV disorders and all have maintained good allograft function during a median follow-up time of 2264 (157-4024) days after the development of symptomatic EBV infection or PTLD. The clinical characteristics of these patients were summarized in Table 1. Although the averages of Tac trough levels for 2 months before the onset of infectious episodes were similar in both patients, those levels at the onset in PTLD group patients were significantly higher than those of non-PTLD group. Moreover, most of the patients developing PTLD showed more than twice trough levels of Tac before infectious episodes.Conclusions: Among infants with an age of less than 2 years old at LDLT, an unexpected increase of Tac trough level at the onset of infectious episodes with sudden positive change of blood EBV DNA load may predict the development of PTLD. In such clinical settings, we need to perform frequent EBV load monitoring and imaging studies.

Exhausted Cytotoxic Control of Epstein-Barr Virus in Human Lupus

Systemic Lupus Erythematosus (SLE) pathology has long been associated with an increased Epstein-Barr Virus (EBV) seropositivity, viremia and cross-reactive serum antibodies specific for both virus and self. It has therefore been postulated that EBV triggers SLE immunopathology, although the mechanism remains elusive. Here, we investigate whether frequent peaks of EBV viral load in SLE patients are a consequence of dysfunctional anti-EBV CD8+ T cell responses. Both inactive and active SLE patients (n = 76 and 42, respectively), have significantly elevated EBV viral loads (P = 0.003 and 0.002, respectively) compared to age- and sex-matched healthy controls (n = 29). Interestingly, less EBV-specific CD8+ T cells are able to secrete multiple cytokines (IFN-γ, TNF-α, IL-2 and MIP-1β) in inactive and active SLE patients compared to controls (P = 0.0003 and 0.0084, respectively). Moreover, EBV-specific CD8+ T cells are also less cytotoxic in SLE patients than in controls (CD107a expression: P = 0.0009, Granzyme B release: P = 0.0001). Importantly, cytomegalovirus (CMV)-specific responses were not found significantly altered in SLE patients. Furthermore, we demonstrate that EBV-specific CD8+ T cell impairment is a consequence of their Programmed Death 1 (PD-1) receptor up-regulation, as blocking this pathway reverses the dysfunctional phenotype. Finally, prospective monitoring of lupus patients revealed that disease flares precede EBV reactivation. In conclusion, EBV-specific CD8+ T cell responses in SLE patients are functionally impaired, but EBV reactivation appears to be an aggravating consequence rather than a cause of SLE immunopathology. We therefore propose that autoimmune B cell activation during flares drives frequent EBV reactivation, which contributes in a vicious circle to the perpetuation of immune activation in SLE patients.

Plasmablastic Cytomorphologic Features in Plasma Cell Neoplasms in Immunocompetent Patients Are Significantly Associated With EBV

Multiple myeloma (MM) is rarely associated with Epstein-Barr virus (EBV) irrespective of HIV status, in contrast with its morphologic mimic, plasmablastic lymphoma, which occurs mainly in immunocompromised patients with frequent EBV association. Among 58 consecutive immunocompetent patients, we found plasmablastic cytomorphologic features in 2 of 4 with plasmacytomas and 14 (26%) of 54 with MM. Of the tumors, 4 (7%; 1 plasmacytoma and 3 MMs) were EBV-encoded RNA (EBER)-positive with plasmablastic cytomorphologic features in 3. The patient with plasmacytoma was disease free for 75 months, and the remaining 3 patients with MM died at 15, 74, and 97 months, respectively; the median survival of patients with EBER- MM was 12 months. EBV+ tumors were associated with plasmablastic cytomorphologic features and high labeling indices. Rare EBER+ plasmablastic plasma cell tumors exist in immunocompetent patients. These tumors may have been driven by EBV to gain the plasmablastic cytomorphologic features and high proliferation fraction. A large cohort study is needed to clarify the prognostic impact of EBV on immunocompetent patients with MM.

Quantitative EBV Viral Loads and Immunosuppression Alterations can Decrease PTLD Incidence in Pediatric Liver Transplant Recipients

Epstein-Barr virus (EBV) is a common viral infection in pediatric liver transplant patients and can lead to development of post-transplant lymphoproliferative disorder (PTLD). Differing studies have used immunosuppression reduction, antiviral medications or i.v. CMV-immunogloublin for EBV prevention and treatment. The purpose of this study was to determine whether implementation of a protocol for frequent EBV monitoring and EBV viral load-driven immunosuppression reduction could decrease the incidence of PTLD in our patient population. All data were prospectively collected between 2001 and 2004 at a single institution. Seventy-three patients were entered into the study. Patients were divided into a historical control group (pre-2001, 30 patients) and a treatment group (post-2001, 43 patients). Approximately 1271 blood samples of 73 patients were collected between 2001 and 2004. Eleven out of 43 patients received immunosuppression tapering due to high EBV viral loads (>4000 copies/microg DNA). One patient developed allograft rejection after immunosuppression modulation. Prior to 2001, the incidence of PTLD at our institution was 16%. After instituting a protocol for EBV monitoring, the incidence of PTLD decreased to 2% (p-value<0.05). These findings illustrate that frequent EBV viral load monitoring and preemptive immunosuppression modulation have an integral role in preventing PTLD in the pediatric liver transplant population.

Survival and clonal expansion of mutating "forbidden" (immunoglobulin receptor-deficient) epstein-barr virus-infected b cells in angioimmunoblastic t cell lymphoma.

Angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is a peculiar T cell lymphoma, as expanding B cell clones are often present besides the malignant T cell clones. In addition, large numbers of Epstein-Barr virus (EBV)-infected B cells are frequently observed. To analyze the differentiation status and clonal composition of EBV-harboring B cells in AILD, single EBV-infected cells were micromanipulated from lymph nodes of six patients with frequent EBV(+) cells and their rearranged immunoglobulin (Ig) genes analyzed. Most EBV-infected B cells carried mutated Ig genes, indicating that in AILD, EBV preferentially resides in memory and/or germinal center B cells. EBV(+) B cell clones observed in all six cases ranged from small polyclonal to large monoclonal expansions and often showed ongoing somatic hypermutation while EBV(-) B cells showed little tendency for clonal expansion. Surprisingly, many members of expanding B cell clones had acquired destructive mutations in originally functional V gene rearrangements and showed an unfavorable high load of replacement mutations in the framework regions, indicating that they accumulated mutations over repeated rounds of mutation and division while not being selected through their antigen receptor. This sustained selection-free accumulation of somatic mutations is unique to AILD. Moreover, the survival and clonal expansion of "forbidden" (i.e., Ig-deficient) B cells has not been observed before in vivo and thus represents a novel type of viral latency in the B cell compartment. It is likely the interplay between the microenvironment in AILD lymph nodes and the viral transformation that leads to the survival and clonal expansion of Ig-less B cells.

Frequent monitoring of Epstein-Barr virus DNA load in unfractionated whole blood is essential for early detection of posttransplant lymphoproliferative disease in high-risk patients

Posttransplant lymphoproliferative disease (PTLD) is a frequent and severe Epstein-Barr virus (EBV)-associated complication in transplantation recipients that is caused by iatrogenic suppression of T-cell function. The diagnostic value of weekly EBV DNA load monitoring was investigated in prospectively collected unfractionated whole blood and serum samples of lung transplantation (LTx) recipients with and without PTLD. In PTLD patients, 78% of tested whole blood samples were above the cut-off value of quantitative competitive polymerase chain reaction (Q-PCR) (greater than 2000 EBV DNA copies per mL blood), with the majority of patients having high viral loads before and at PTLD diagnosis. Especially in a primary EBV-infected patient and in patients with conversion of immunosuppressive treatment, rapid increases in peripheral blood EBV DNA load diagnosed and predicted PTLD. In non-PTLD transplantation recipients, only 3.4% of the whole blood samples was above the cut-off value (P <.0001) despite heavy immune suppression and cytomegalovirus (CMV)-related disease. These findings illustrate the clinical importance of frequent EBV DNA load monitoring in LTx recipients. The increased EBV DNA loads in PTLD patients were restricted to the cellular blood compartment, as parallel serum samples were all below cut-off value, which indicates absence of lytic viral replication. EBV(+) cells in PTLD patients have a very short doubling time, which can be as low as 56 hours, thereby creating the need for high screening frequency in high-risk patients. Furthermore, it is shown that EBV and CMV can reactivate independently in LTx recipients and that EBV DNA load monitoring may be useful in discriminating PTLD from rejection.

Natural history of primary Epstein-Barr virus infection in children of mothers infected with human immunodeficiency virus type 1.

The natural history of Epstein-Barr virus (EBV) infection in 556 infants born to 517 human immunodeficiency virus (HIV) type 1-infected mothers was studied in a prospective, multicenter, cohort study. HIV-1-infected children had a cumulative EBV infection rate similar to HIV-1-uninfected children at age 3 years (77.8% vs. 84. 9%) but had more frequent oropharyngeal EBV shedding (50.4% vs. 28. 2%; P<.001). The probability of shedding decreased with longer time from EBV seroconversion and was similar to that of HIV-1-uninfected children 3 years after seroconversion. HIV-1-infected children identified as rapid progressors shed EBV more frequently than nonrapid progressors (69.4% vs.41.0%; P=.01). HIV-1-infected children with EBV infection had higher mean CD8 cell counts. EBV infection did not have an independent effect on mean CD4 cell counts, percent CD4, IgG levels, HIV-1 RNA levels, lymphadenopathy, hepatomegaly, or splenomegaly. Early EBV infection is common in children born to HIV-1-infected mothers. Children with rapidly progressive HIV-1 disease have more frequent EBV shedding.

Genetic basis of acquired immunodeficiency syndrome-related lymphomagenesis.

The molecular pathogenesis of systemic acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphomas (AIDS-NHL) is a complex process involving both host factors and the accumulation of genetic lesions within the tumor clone. On the basis of the pattern of molecular lesions involved in these tumors, several distinct pathogenetic pathways can be presently identified in AIDS-related lymphomagenesis. These pathways selectively associate with the different clinicopathologic variants of AIDS-NHL. AIDS-related Burkitt's lymphoma is characterized by activation of c-MYC in all cases, disruption of p53 in 60% of the cases, and infection by Epstein-Barr virus (EBV) in 30% of the cases. AIDS-related diffuse large-cell lymphoma harbor frequent EBV infection (80%) and, in 20% of the cases, BCL-6 rearrangements. Finally, the pathogenesis of AIDS-related body cavity-based lymphoma involves infection by human herpesvirus-8 in all cases and frequently also the co-infection by EBV.

Frequent presence of latent Epstein-Barr virus infection in peripheral T cell lymphomas. A review.

Two-hundred and four cases of peripheral T cell lymphoma (PTCL) occurring in Europeans without any sign of HIV-infection were investigated for their association with an Epstein-Barr virus (EBV) infection. Polymerase chain reaction (PCR) was applied for EBV-DNA detection, in situ hybridisation (ISH) for the cellular localization of EBV-encoded small nuclear RNA (EBER) and immediate early gene expression (BHLF) and immunohistology (IH) for the detection of EBV-encoded latent membrane protein 1 (LMP1) and EBV nuclear antigen 2 (EBNA2) expression. PCR and EBER-ISH produced congruent results in almost all cases with amplifiable DNA, leading to the finding of an overall frequency of EBV presence in 87/204 (42.6%) of the PTCL cases. Through EBER-ISH, the virus was identified to be exclusively present in small and blastic bystander lymphocytes in 29 cases, whilst an additional infection of neoplastic T cells was observed in the remaining 58 EBV-positive cases. The entity presenting with the most frequent EBV infection of tumour cells was that of angioimmunoblastic type PTCL, whilst the primary cutaneous PTCLs only seldom harbored the virus. Forty-eight of the EBV-positive TCLs showed an infection of a small proportion (1-20%) of the tumour cell population, whilst another ten cases, belonging to the pleomorphic TCL (PMTCL) group, displayed an infection of several to almost all neoplastic T cells (20-100%). Additional lytic EBV-infected cells could be detected in four cases by BHLF-ISH. LMP1 expression was present in a small proportion of the neoplastic T cells in 24 of the 58 cases with tumour cell infection, whilst an EBNA2 expression was detectable only in one case. Some non-malignant EBV-infected B-immunoblasts and Hodgkin/Reed Sternberg-like cells also expressed LMP1 in several cases. Our data imply a role of EBV in the pathogenesis of only a few PMTCL cases with predominant tumour cell infection, whilst the pathogenic significance of an EBV infection in the other PTCLs remains unclear due to the usually partial infection of the neoplastic cell component.

Frequent Latent Epstein-Barr Virus Infection of Neoplastic T Cells and Bystander B Cells in Human Immunodeficiency Virus-Negative European Peripheral Pleomorphic T-Cell Lymphomas

We investigated 81 cases of peripheral pleomorphic T-cell lymphoma (PMTCL) occurring in human immunodeficiency virus-negative Europeans for the presence of Epstein-Barr virus (EBV)-DNA through polymerase chain reaction (PCR) for the presence of EBV-encoded small nuclear RNAs (EBER) and immediate early mRNAs (Bam H-fragment, lower strand frame [BHLF]) by in situ hybridization (ISH) and for EBV-encoded latent membrane protein (LMP) and nuclear antigen 2 (EBNA2) by immunohistology (IH). EBER-ISH, which could be applied on all cases, showed an overall incidence of EBV-infected cells in 38 of 81 cases (47%) of PMTCL. These data could be confirmed by PCR, which produced congruent results in the cases with amplifiable DNA. By EBER-ISH, the virus was located in the tumor cells in 30 of the 38 EBV-positive cases, with the proportion of the infected cells ranging from 1% to 100%. In 18 of these cases and in the 8 cases without EBV-infected tumor cells, the virus was, respectively, either additionally or exclusively detectable in occasional nonmalignant lymphoid bystander cells. An LMP expression was observed in several of the EBER-expressing tumor cells in 18 cases, whereas EBNA2 was detectable only in one case, which also displayed signs of viral replication. Some nonmalignant EBV-infected B immunoblasts also expressed LMP in several cases. Primary cutaneous and enteropathy-associated PMTCL displayed less frequent EBV infection when compared with other extranodal or nodal manifestations.