Haematological associations of Epstein-Barr virus infection

Quantitative Off-Target Detection of Epstein-Barr Virus-Derived DNA in Routine Molecular Profiling of Hematopoietic Neoplasms by Panel-Based Hybrid-Capture Next-Generation Sequencing

Epstein-Barr virus (EBV) is associated with hematologic and solid tumors. We utilized a hybridization capture-based next-generation sequencing (NGS) platform targeting 400 genes associated with hematological malignancies to detect and quantify nontargeted viral-derived EBV reads that aligned to the EBV reference contig (NC_007605). We evaluated 5234 samples from 3636 unique patients with hematological neoplasms and found that 100 samples (1.9%) in 93 unique patients had ≥6 EBV reads (range, 6 to 32,325; mean, 827.5; median, 54). Most (n = 73, 73%) represented known EBV-associated conditions, and the most common was post-transplant lymphoproliferative disorders (n = 21, 29%). Documented EBV viremia was found in 4 of 27 samples with a moderate quantity of EBV reads and conditions not known to be EBV associated, whereas suspected viremia or low-level activation was likely in the remaining 23 samples. A good correlation (Spearman r = 0.8; 95% CI, 0.74-0.85) was found between EBV reads by NGS and systematic semiquantitative EBV-encoded RNA in situ hybridization in 162 available samples, particularly at greater EBV involvement. An optimal threshold for significant morphologic EBV involvement was found to be ≥10 reads by the receiver operating characteristic analysis (area under the curve, 0.990; 95% CI, 0.9974%-1.000%). Thus, in addition to mutational analysis, hybrid-capture-based NGS panels can detect and quantitate off-target EBV-derived viral DNA, which correlates well with morphology.

Acute fibrinous and organizing pneumonia complicated with hemophagocytic lymphohistiocytosis caused by chronic active Epstein-Barr virus infection: a case report

Background

Acute fibrinous and organizing pneumonia (AFOP) is a rare lung condition that is associated with acute lung injury. Its etiology may be idiopathic or secondary to a series of conditions, including immune-related diseases, unclassified connective tissue diseases, hematopoietic stem cell transplantation, infections, hematological diseases and drug induced lung toxicity. We report for the first time a case of AFOP complicated with hemophagocytic lymphohistiocytosis (HLH) caused by chronic active Epstein-Barr virus (CAEBV) infection.

Case presentation

A 64-year-old man was admitted with a complaint of fever and dyspnea for 2 weeks. The patient presented with elevated serum aminotransferase levels, splenomegaly, progressive decrease of red blood cells and platelets, hyperferritinemia, hypofibrinogenemia, and elevated of Soluble interleukin-2 receptor (sCD25). His chest computed tomography (CT) scan revealed multiple patchy consolidation in both lungs and multiple lymphadenopathy in the mediastinum and hilum. The serology for antibodies of VCA-IgG was positive, EBV-DNA in peripheral blood was elevated, and EBV nucleic acid was detected in the alveolar lavage fluid. Histopathology of the lung tissue showed a dominant of intra-alveolar fibrin and organizing pneumonia. Hemophagocytic cells was found in the bone marrow smear and biopsy. EBV-DNA was detected in lung tissue and bone marrow using in situ hybridization with an EBV-encoded RNA (EBER) probe. After 50 days of hospitalization, he was improved in lung and hemogram.

Conclusion

We report a case of AFOP with HLH caused by CAEBV in an immunocompetent adult, suggesting that AFOP may be a rare but serious complication caused by CAEBV, and glucocorticoid therapy may improve short-term prognosis.

Novel Functions and Virus-Host Interactions Implicated in Pathogenesis and Replication of Human Herpesvirus 8

Human herpesvirus 8 (HHV-8) is classified as a γ2-herpesvirus and is related to Epstein-Barr virus (EBV), a γ1-herpesvirus. One important aspect of the γ-herpesviruses is their association with neoplasia, either naturally or in animal model systems. HHV-8 is associated with B-cell-derived primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD), endothelial-derived Kaposi's sarcoma (KS), and KSHV inflammatory cytokine syndrome (KICS). EBV is also associated with a number of B-cell malignancies, such as Burkitt's lymphoma, Hodgkin's lymphoma, and posttransplant lymphoproliferative disease, in addition to epithelial nasopharyngeal and gastric carcinomas. Despite the similarities between these viruses and their associated malignancies, the particular protein functions and activities involved in key aspects of virus biology and neoplastic transformation appear to be quite distinct. Indeed, HHV-8 specifies a number of proteins for which counterparts had not previously been identified in EBV, other herpesviruses, or even viruses in general, and these proteins are believed to play vital functions in virus biology and to be involved centrally in viral pathogenesis. Additionally, a set of microRNAs encoded by HHV-8 appears to modulate the expression of multiple host proteins to provide conditions conductive to virus persistence within the host and possibly contributing to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.

Pathogenesis and Immune Response Caused by Vector-Borne and Other Viral Infections in a Tupaia Model

The Tupaia or tree shrew (Tupaia belangeri), a small mammal of the Tupaiidae family, is an increasingly used and promising infection model for virological and immunological research. Recently, sequencing of the Tupaia whole genome revealed that it is more homologous to the genome of humans than of rodents. Viral infections are a global threat to human health, and a complex series of events are involved in the interactions between a virus and the host immune system, which play important roles in the activation of an immune response and the outcome of an infection. Majority of immune response data in viral infections are obtained from studies using animal models that enhance the understanding of host-virus interactions; a proper understanding of these interactions is very important for the development of effective antivirals and prophylactics. Therefore, animal models that are permissive to infection and that recapitulate human disease pathogenesis and immune responses to viral infections are essential. Several studies have shown the permissiveness of Tupaia to a number of important human viral infections in vitro and in vivo without prior adaptation of the viruses; the immune responses and clinical manifestations were comparable to those observed in human infections. Thus, the Tupaia is being utilized and developed as a promising immunocompetent small animal model for viral infection studies. In this review, we focused on the immune responses, mostly innate, during viral infection and pathogenesis in the Tupaia model; we evaluated the interaction between the virus and the components of host resistance, the usefulness of this model for immunopathogenesis studies, and the vaccines and antivirals available.

EBV-related Cold Agglutinin Disease Presenting With Conjugated Hyperbilirubinemia: A Pediatric Case Report and Mini Review

Hemolytic anemia occurs in only 1% to 3% of hospitalized patients with infectious mononucleosis. The authors describe an 8-year-old girl without cervical lymphadenopathy or splenomegaly, who presented with conjugated hyperbilirubinemia and was diagnosed with cold agglutinin disease caused by an immunoglobulin M autoantibody with anti-i specificity. Acute Epstein-Barr virus infection was confirmed by serologic and molecular methods. She recovered uneventfully after a 3-week course of methylprednisolone. Epstein-Barr virus infection should be considered in any case of hemolytic anemia associated with hepatic dysfunction, especially when direct antiglobulin test is positive for C3d. In these cases, a course of corticosteroids seems safe and may be beneficial.

Amegakaryocytic Thrombocytopenia and Subsequent Aplastic Anemia Associated with Apparent Epstein-Barr Virus Infection

Acquired amegakaryocytic thrombocytopenia (AAT), a rare entity characterized by severe thrombocytopenia and the absence of megakaryocytes in the bone marrow, may mimic or precede the diagnosis of aplastic anemia (AA). Here, we describe a patient who presented with apparent Epstein-Barr virus (EBV)-associated immune thrombocytopenia resistant to several lines of therapies, which was in fact a form of AAT with some features of AA. He eventually responded to therapy with eltrombopag, cyclosporine A (CSA), and antithymocyte globulin (ATG) and recovered completely. EBV infection is known to cause a variety of benign and malignant hematologic disorders, including bone marrow failure. However, to the best of our knowledge, this is the first case report of EBV-associated AAT. Treatment options for AAT are still not well defined, and even response to eltrombopag together with CSA and ATG does not always imply successful therapy. The natural history of EBV infection may well be sufficient to explain unexpected eventual recovery.

The Putative Role of Viruses, Bacteria, and Chronic Fungal Biotoxin Exposure in the Genesis of Intractable Fatigue Accompanied by Cognitive and Physical Disability

Patients who present with severe intractable apparently idiopathic fatigue accompanied by profound physical and or cognitive disability present a significant therapeutic challenge. The effect of psychological counseling is limited, with significant but very slight improvements in psychometric measures of fatigue and disability but no improvement on scientific measures of physical impairment compared to controls. Similarly, exercise regimes either produce significant, but practically unimportant, benefit or provoke symptom exacerbation. Many such patients are afforded the exclusionary, non-specific diagnosis of chronic fatigue syndrome if rudimentary testing fails to discover the cause of their symptoms. More sophisticated investigations often reveal the presence of a range of pathogens capable of establishing life-long infections with sophisticated immune evasion strategies, including Parvoviruses, HHV6, variants of Epstein-Barr, Cytomegalovirus, Mycoplasma, and Borrelia burgdorferi. Other patients have a history of chronic fungal or other biotoxin exposure. Herein, we explain the epigenetic factors that may render such individuals susceptible to the chronic pathology induced by such agents, how such agents induce pathology, and, indeed, how such pathology can persist and even amplify even when infections have cleared or when biotoxin exposure has ceased. The presence of active, reactivated, or even latent Herpes virus could be a potential source of intractable fatigue accompanied by profound physical and or cognitive disability in some patients, and the same may be true of persistent Parvovirus B12 and mycoplasma infection. A history of chronic mold exposure is a feasible explanation for such symptoms, as is the presence of B. burgdorferi. The complex tropism, life cycles, genetic variability, and low titer of many of these pathogens makes their detection in blood a challenge. Examination of lymphoid tissue or CSF in such circumstances may be warranted.

Epstein-Barr virus serology and PCR: conflicting results in an immunocompetent host. A case report and review of literature

We present the case of a 27-year-old immunocompetent man who progressively developed a generalized lymphadenopathy and B symptoms. Results of Epstein-Barr virus (EBV) serology were suggestive for a past infection, but the EBV viral load in whole blood was high. Also, core needle biopsy of the largest lymph node showed an image which could fit an EBV-driven reactive lymphoproliferation. Despite the absence of an immune disorder, all medical evidence points to an EBV-driven lymphoproliferative proces. In immunocompetent patients, it seems extremely uncommon to detect a high EBV viral load in the absence of serological evidence of an acute EBV infection or reactivation. We reviewed literature on this topic and on the selection of the appropriate sample type for EBV PCR, as this is known to be a critical point. Serological testing for the diagnosis of EBV infection is the gold standard in immunocompetent patients. Measuring EBV viral load is only recommended when dealing with immunocompromised patients. Although extremely rare, this case report shows that there is a place for EBV PCR in certain situations in immunocompetent patients. Besides, there is still no consensus regarding the specimen of choice for the determination of the EBV viral load. The preferred specimen type seems to depend on the patient's underlying condition.

Molecular biology of human herpesvirus 8: novel functions and virus-host interactions implicated in viral pathogenesis and replication

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the second identified human gammaherpesvirus. Like its relative Epstein-Barr virus, HHV-8 is linked to B-cell tumors, specifically primary effusion lymphoma and multicentric Castleman's disease, in addition to endothelial-derived KS. HHV-8 is unusual in its possession of a plethora of "accessory" genes and encoded proteins in addition to the core, conserved herpesvirus and gammaherpesvirus genes that are necessary for basic biological functions of these viruses. The HHV-8 accessory proteins specify not only activities deducible from their cellular protein homologies but also novel, unsuspected activities that have revealed new mechanisms of virus-host interaction that serve virus replication or latency and may contribute to the development and progression of virus-associated neoplasia. These proteins include viral interleukin-6 (vIL-6), viral chemokines (vCCLs), viral G protein-coupled receptor (vGPCR), viral interferon regulatory factors (vIRFs), and viral antiapoptotic proteins homologous to FLICE (FADD-like IL-1β converting enzyme)-inhibitory protein (FLIP) and survivin. Other HHV-8 proteins, such as signaling membrane receptors encoded by open reading frames K1 and K15, also interact with host mechanisms in unique ways and have been implicated in viral pathogenesis. Additionally, a set of micro-RNAs encoded by HHV-8 appear to modulate expression of multiple host proteins to provide conditions conducive to virus persistence within the host and could also contribute to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.

Acute or chronic life-threatening diseases associated with Epstein-Barr virus infection

Infectious mononucleosis (IM) is one of the representative, usually benign, acute diseases associated with primary Epstein-Barr virus (EBV) infection. IM is generally self-limiting and is characterized mostly by transient fever, lymphadenopathy and hepatosplenomegaly. However, very rarely primary EBV infection results in severe or fatal conditions such as hemophagocytic lymphohistiocytosis together with fulminant hepatitis designated as severe or fatal IM or EBV-associated hemophagocytic lymphohistiocytosis alone. In addition, chronic EBV-associated diseases include Burkitt's lymphoma, undifferentiated nasopharyngeal carcinoma, Hodgkin lymphoma, T-cell lymphoproliferative disorder (LPD)/lymphoma, natural killer-cell LPD including leukemia or lymphoma, gastric carcinoma, pyothorax-associated lymphoma and senile B-cell LPD as well as chronic active EBV infection and LPD/lymphoma in patients with immunodeficiency. The number of chronic life-threatening diseases linked to the EBV infection is increasingly reported and many of these diseases have a poor prognosis. This review will focus on the historical, pathogenetic, diagnostic, therapeutic and prophylactic issues of EBV-associated life-threatening diseases.

HCV infection and B-cell lymphomagenesis

Hepatitis C virus (HCV) has been recognized as a major cause of chronic liver diseases worldwide. It has been suggested that HCV infects not only hepatocytes but also mononuclear lymphocytes including B cells that express the CD81 molecule, a putative HCV receptor. HCV infection of B cells is the likely cause of B-cell dysregulation disorders such as mixed cryoglobulinemia, rheumatoid factor production, and B-cell lymphoproliferative disorders that may evolve into non-Hodgkin's lymphoma (NHL). Epidemiological data indicate an association between HCV chronic infection and the occurrence of B-cell NHL, suggesting that chronic HCV infection is associated at least in part with B-cell lymphomagenesis. In this paper, we aim to provide an overview of recent literature, including our own, to elucidate a possible role of HCV chronic infection in B-cell lymphomagenesis.

Cancer mortality in a Chinese population surrounding a multi-metal sulphide mine in Guangdong province: an ecologic study

BACKGROUND

The Dabaoshan mine in the southeast of Guangdong Province, China, is at high risk of multi-metal pollutant discharge into a local river (Hengshihe) and the surrounding area. Following approximately 30 years of exposure to these metals, little is known regarding the subsequent health effects and risks for the local residents. In our present study, we have estimated the relationships between long-term environmental exposure to multiple heavy metals and the risk of cancer mortality in a Chinese population in the vicinity of Dabaoshan.

METHODS

An ecologic study was performed. Between 2000-2007, a total population of 194,131 lived in the nine agricultural villages that surround the Hengshihe area. Heavy metals concentrations were determined in local environmental samples (water and crops) and whole blood taken from 1152 local residents of both a high-exposure area (HEA) and a low-exposure area (LEA). We calculated the rate ratio and standardized mortality ratios based on age- and gender-specific cancer mortality rates for the different reference populations (based on district, county and province). Simple, multiple linear and ridge regression models were used to evaluate the associations between exposure to multiple heavy metals and cancer mortality in the nine villages, after adjustment for age and sex.

RESULTS

The geometric mean blood levels of cadmium and lead were measured at 24.10 μg/L and 38.91 μg/dL for subjects (n = 563) in the HEA and 1.87 μg/L and 4.46 μg/dL for subjects (n = 589) from the LEA, respectively (P < 0.001). The rate of mortality from all cancers in the HEA was substantially elevated in comparison with the corresponding mortality rate in the LEA for men (rate ratio = 2.13; 95% confidence intervals = 1.63 - 2.77) and women (2.83; 1.91 - 4.19); rates were also significantly elevated compared with the rate when compared to the entire Wengyuan County area, or the provincial reference population. In addition, mortality rates were significantly increased for stomach, lung and esophageal cancer in the HEA in comparison with the corresponding rates in the LEA, in Wengyuan County and the provincial reference population for men, women and both combined. Further analysis showed that there were significantly positive correlations between exposure to cadmium and lead and the risk of all-cancers and stomach cancer mortality among women and both sexes, whilst zinc exposure showed no association with the risk of site-specific cancer mortality in the nine villages evaluated.

CONCLUSIONS

The findings of this study reveal probable associations between long-term environmental exposure to both cadmium and lead and an increased risk of mortality from all cancer, as well as from stomach, esophageal and lung-cancers.

Microbiological findings and treatment of EBV-associated hemophagocytic lymphohistiocytosis: a case report

Epstein-Barr virus (EBV) is the major triggering factor for hemophagocytic syndrome or hemophagocytic lymphohistiocytosis (HLH). In patients with EBV-HLH, the EBV-infected T cells or natural killer cells are mostly mono- or oligoclonally proliferating, whereby hypercytokinemia plays a major role and causes hemophagocytosis, cellular damage, and dysfunction of various organs. This report describes the detection and treatment of EBV-associated HLH in the case of a 17-year-old male. Serum samples and skin swabs were tested for the presence of viral DNA using real-time PCR techniques. To confirm the molecular biological tests, electron microscopy was also performed. EBV DNA was detected with real-time PCR in both blood samples and skin swabs. The level of viral DNA constantly decreased during the applied therapy. The presence of the virus in the skin was confirmed by the appearance of herpes virus-like particles detected by electron microscopy in fluid taken from skin ulcerations. The results show that in terms of treatment, special therapeutic measures are required to control the cytokine storm generated by EBV and to suppress proliferating EBV genome-containing cells because the clinical course is often fulminate and results in a poor outcome. Therefore the potential of chemotherapy with a combination of steroids, etoposide, and cyclosporine to control HLH was assessed in the adolescent, who met the stringent diagnostic criteria for this reactive disorder of the mononuclear phagocyte system.

Hepatitis C virus infection and lymphoma

Apart from its well known role as an etiological agent for non-A and non-B viral hepatitis, there is growing evidence that hepatitis C virus is associated to B-cell non-Hodgkin lymphoma. The association between HCV and lymphoproliferative disorders has been recently postulated based on epidemiological data, biological studies and clinical observations. Although various subtypes of lymphomas appear to be associated to HCV, diffuse large B-cell lymphoma, small lymphocytic lymphoma/chronic lymphocytic leukemia and marginal zone lymphoma appeared to be particularly represented among HCV-positive patients. The causative role of HCV in those disorders has been further supported by the response to antiviral therapy. Despite a better understanding of pathophysiological processes at stake leading from HCV infection to overt lymphoma, many issues still need to be further elucidated. Although HCV has been demonstrated to directly infect peripheral blood mononuclear cells both in vitro and, in some cases, in vivo, a strong body of evidence rather supports the hypothesis of an indirect transformation mechanism by which sustained antigenic stimulation leads from oligoclonal to monoclonal expansion and sometimes to lymphoma, probably through secondary oncogenic events. Here, we review epidemiological and biological studies, as well as clinical data on antiviral therapy, linking HCV-infection to B-cell non-Hodgkin lymphoma.

Occupational exposure to pesticides and risk of hematopoietic cancers: meta-analysis of case–control studies

OBJECTIVE

In this study we conducted a meta-analysis of 13 case-control studies that examined the occurrence of hematopoietic cancers in pesticide related occupations in order to undertake a qualitative and quantitative evaluation of a possible relationship.

METHODS

Pubmed databases were searched for case-control studies published between 1990 and 2005 investigating the relation between hematopoietic cancers and occupational exposure to pesticides. Fixed and random effect meta-analysis models were used depending on the presence of heterogeneity between studies.

RESULTS

The overall meta-odds ratio obtained after pooling 44 ORs from 13 studies was 1.3 (95% CI: 1.3-1.5). We realized stratified analysis on three different types of hematopoietic cancers (non-Hodgkin lymphoma (NHL), leukemia and multiple myeloma). A significant increased risk of NHL was found (OR = 1.35; 95% CI = 1.2-1.5). Moreover, increased risks of Leukemia (OR = 1.35; 95% CI = 0.9-2) and multiple myeloma (OR = 1.16; 95% CI = 0.99-1.36) were also detected but these results were not statistically significant. Significant heterogeneity existed among the different studies and a publication bias was detected. Therefore, a meta-regression was carried out. Our results showed that a long period of exposure (more than 10 years) provided an increase in the risk of all hematopoietic cancers and for NHL by fractions of 2.18 (95% CI = 1.43-3.35) and 1.65 (95% CI = 1.08-2.51), respectively.

CONCLUSIONS

The overall meta-odds ratio suggests that there is a significantly positive association between occupational exposure to pesticides and all hematopoietic cancers as well as NHL. A major limitation of our meta-analysis is the lack of sufficient data about exposure information and other risk factors for hematopoietic cancer (genetic predisposition, ethnic origin, immunodepression...). In addition, data concerning specific subtypes of hematopoietic cancers are often confusing. Thus, future epidemiological studies should undertake a major effort to assess the identity and the level of pesticides exposure and should control for the most likely potential confounders.

Advanced therapeutic and prophylactic strategies for Epstein-Barr virus infection in immunocompromised patients

Epstein-Barr virus (EBV) is an ubiquitous human herpesvirus. Primary infection is generally subclinical but in certain circumstances, such as in patients with either hereditary or secondary immunodeficiency, EBV infection may cause overt disease that is often lethal. Strategies for the prophylaxis and treatment of these potentially life-threatening complications of EBV infection have advanced dramatically. They include immunological-based approaches targeted at EBV-infected cells, as well as improvement in the treatment of the underlying and predisposing disease. This review will discuss EBV biology and immune events that occur in both immunocompetent and immunocompromised individuals and introduce the novel prophylactic and therapeutic strategies for EBV-associated life-threatening diseases.

Epstein-Barr virus-associated lymphomas

Following Epstein and colleagues' ground-breaking discovery of Epstein-Barr virus by electron microscopy of Burkitt's lymphoma cell lines, there came the observation that Epstein-Barr virus induces immortalization of B cells in vitro. Thus, initial hopes were of a virus confined to equatorial Africa with a causal link to a particular subtype of childhood lymphoma. Over the past 40 years there has been great progress towards understanding the biology and epidemiology of Epstein-Barr virus, which conclusively show that these early ideas were overly simplistic. It is now known that Epstein-Barr virus has a seroprevalence of approximately 95% worldwide, and persists for life within host B lymphocytes. Infection in New World primates leads to lymphoma and inoculation of peripheral blood mononuclear cells from Epstein-Barr virus-seropositive subjects into severe combined immunodeficiency mice results in B-cell lymphoproliferative disorders. Epstein-Barr virus is now known to be implicated in a range of lymphoid and other malignancies, and this association will be the subject of this review.

Proposed guidelines for diagnosing chronic active Epstein-Barr virus infection

Since the initial report of unusual manifestations possibly associated with chronic active Epstein-Barr virus (EBV) infection (CAEBV), nearly three decades have passed. During this period, reported cases with this entity have dramatically increased in the world. Additionally, recent development of diagnostic procedures, including molecular biological and immunological techniques, have provided us with the ability to define certain diseases, especially malignant disorders. Guidelines, derived mainly from the current literature and recent experiences with CAEBV in Japan, for diagnosing CAEBV are proposed to clarify this enigmatic disease.

Overview and problematic standpoints of severe chronic active Epstein-Barr virus infection syndrome

Epstein-Barr virus (EBV) is an ubiquitous human herpesvirus. Its infection is generally subclinical. However, in certain circumstances, EBV causes infectious mononucleosis (IM) and lymphoproliferative disorders (LPD) in immunologically compromised individuals. Furthermore, EBV infection is etiologically linked to human malignancies such as Burkitt's lymphoma (BL), nasopharyngeal carcinoma (NPC) and miscellaneous malignant diseases because of the presence of viral genome in their tumor tissues. Since the late 1970s, a chronic undefined illness possibly associated with EBV infection, named such as severe chronic active EBV infection syndrome (SCAEBV), has been of interest due to its unique manifestations that often result in a poor prognosis. This review is an overview of SCAEBV with respect to its; history, diagnosis, pathogenesis, therapeutic approaches, and ideas on how to further recognize this enigmatic disease.

Reovirus therapy of lymphoid malignancies

Reoviruses infect cells that manifest an activated Ras-signaling pathway, and have been shown to effectively destroy many different types of neoplastic cells, including those derived from brain, breast, colon, ovaries, and prostate. In this study, we investigated the reovirus as a potential therapeutic agent against lymphoid malignancies. A total of 9 lymphoid cell lines and 27 primary human lymphoid malignancies, as well as normal lymphocytes and hematopoietic stem/progenitor cells, were tested for susceptibility to reovirus infection. For in vitro studies, the cells were challenged with reovirus (serotype 3 Dearing), and viral infection was assessed by cytopathic effects, viability, viral protein synthesis, and progeny virus production. We present evidence of efficient reovirus infection and cell lysis in the diffuse large B-cell lymphoma cell lines and Burkitt lymphoma cell lines Raji and CA46 but not Daudi, Ramos, or ST486. Moreover, when Raji and Daudi cell lines were grown subcutaneously in severe combined immunodeficient/nonobese diabetic (SCID/NOD) mice and subsequently injected with reovirus intratumorally or intravenously, significant regression was observed in the Raji-induced, but not the Daudi-induced, tumors, which is consistent with the in vitro results. Susceptibility to reovirus infection was also detected in 21 of the 27 primary lymphoid neoplasias tested but not in the normal lymphocytes or hematopoietic stem/progenitor cells. Our results suggest that reovirus may be an effective agent against several types of human lymphoid malignancies.

From Burkitt's lymphoma to chronic active Epstein-Barr virus (EBV) infection: an expanding spectrum of EBV-associated diseases

Epstein-Barr virus (FBV) is one of 8 known human herpesviruses. EBV infection usually occurs in early childhood and is subclinical. However, primary infection in adolescence or adulthood causes infectious mononucleosis in approximately half of infected individuals. Recently, the spectrum of human diseases associated with EBV injection has increased, primarily due to methodological advances in EBV detection. Initially, EBV was isolated from a cultured Burkitt lymphoma cell line, and has been felt to be etiologically linked to the development of Burkitt lymphoma, as well as other human malignancies. This review mainly focuses on pathogenetic mechanisms, many of which remain enigmatic, for the various human diseases, which are considered to be associated with EBV injection.

Epstein-Barr virus in patients with immunodeficiency disorders

The Epstein-Barr virus (EBV), one of eight known human herpesviruses, causes a wide spectrum of diseases under certain conditions. In particular, in the setting of immunodeficiency, which includes primary or secondary/acquired immunodeficiencies, they have been increasingly reported. The major clinical phenotype is the EBV genome-positive lymphoproliferative disorder, which ranges from benign lymphoproliferation to malignant lymphoma with cytogenetic alterations. Severe or fatal infectious mononucleosis may develop in some patients with immunodeficiencies such as X-linked lymphoproliferative disease.