Epstein-Barr virus in AIDS-related primary central nervous system lymphoma

The role of chemical, physical, or viral exposures and health factors in neurocarcinogenesis: implications for epidemiologic studies of brain tumors

This review highlights some future prospects and implications for epidemiologic research on the etiology of nervous system tumors. It reviews some points regarding physiology of the nervous system, in connection with mechanisms of neurocarcinogenesis, and experimental studies in animals. The results of epidemiologic studies are summarized in the light of the biological and experimental observations. The following aspects are particularly emphasized: (i) higher susceptibility of the developing nervous system to neurocarcinogenic agents (in the fetus and after birth); (ii) possible implications of knowledge about mechanisms of neurocarcinogenesis regarding crossing of the blood-brain barrier, activation of oncogenes and inactivation of anti-oncogenes, relationship between chemical structure and neurocarcinogenic action; (iii) necessity of further investigation concerning the occurrence of nitrosoureas and their precursors in the environment, and the potential role of nitroso compounds in the development of human brain tumors; (iv) lack of information about promoting or inhibiting neurocarcinogenic effects, and co-carcinogenesis--among others, interaction between X-irradiation and exposure to neurocarcinogenic nitrosoureas; (v) need for studying the potential neurocarcinogenic risk of polyomaviruses BKV, JCV, and SV40 to humans.

Epstein-Barr virus associated lymphoproliferative disorder with fatal involvement of the gastrointestinal tract in an infant

A case of fatal Epstein-Barr virus (EBV) associated lymphoproliferative disorder is reported in an 11 month old female. Heavy infiltrates of CD20 + and EBV EBER mRNA expressing lymphoid blasts were found to cause a series of ulcers along the entire length of the gastrointestinal tract and there was an ileal perforation. Similar infiltrates were also found in lymph nodes, spleen, and liver. Although blood phenotypic analysis performed shortly before her death revealed a severe decrease in T lymphocytes, neither the patient nor other members of her family had a history of primary or secondary immunodeficiency. EBV infection is common in children. However, such a fatal infection of the virus has not apparently been described previously in infants without pre-established immunodeficiency.

Contribution of conserved amino acids in mediating the interaction between EBNA2 and CBF1/RBPJk

The Epstein-Barr virus EBNA2 protein is a transcriptional activator that achieves promoter specificity through interaction with the cellular DNA-binding protein CBF1/RBPJk. Within the amino acid 252-to-425 EBNA2 domain that targets CBF1/RBPJk lie three amino acid clusters, conserved regions (CR) 5, 6, and 7, that are retained in the Epstein-Barr virus type A and type B and herpesvirus papio proteins. To further define the important features of the targeting domain, we constructed EBNA2 polypeptides containing deletions in the targeting domain and double or triple point mutations in the conserved motifs. The ability of these polypeptides and the type B and herpesvirus papio domains to interact with CBF1/RBPJk was examined by performing electrophoretic mobility shift assays and correlated with the effect of the mutations on EBNA2 transactivation. Both human type B EBNA2 and herpesvirus papio EBNA2 bound CBF1/RBPJk efficiently. Mutation of hydrophobic residues in CR6 severely impaired CBF1/RBPJk interaction and transactivation, while mutation of CR5 led to a moderate decrease in both activities. Mutation of CR7 had only a minor effect. Synthetic peptides corresponding to each of the conserved motifs were also used as competitors in an electrophoretic mobility shift assay. Only the peptide representing CR6 (amino acids 318 to 327), and not a version of this peptide mutated at the tryptophan residues at positions 323 and 324 (WW323,324), could compete for EBNA2 complex formation with CBF1/RBPJk. Overall, the data indicated that CR5 contributes to an optimal interaction, perhaps through stabilizing contacts, while CR6 forms a crucial interface with CBF1/RBPJk. The peptide competition data are consistent with direct contacts between WW323,324 and CBF1/RBPJk.

Cytokine expression in large cell lymphoma associated with acquired immunodeficiency syndrome

Cytokine expression was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) in a retrospective sampling of 16 AIDS-associated large cell lymphomas (LCL). IL-6 receptor (IL-6R) and IL-10 expression was detected in a majority of the tumor specimens tested, IL-6 expression was detected in 5 of 16 lymphomas that also expressed IL-6R, suggestive of an autocrine mechanism of disease. A subset of tumor samples described as mixed immunophenotype contained large numbers of infiltrating T lymphocytes and macrophages. Immunoperoxidase staining of a representative tumor of mixed immunophenotype demonstrated the presence of HIV-infected macrophages that also stained with anti-IL-6. This finding suggests that IL-6 produced by nonlymphoid cells may act as a paracrine growth factor for tumor cells that express IL-6R. Although earlier studies of AIDs burkitt's lymphoma cell lines suggested that IL-10 expression required EBV infection, 7 of 12 AIDS LCLs that expressed IL-10 did so in the absence of EBV by EBER in situ hybridization. Because AIDS LCLs frequently express cell surface CD5, we speculate that IL-10 may act as an autocrine or paracrine growth factor for this class of lymphoma. These studies suggest that IL-6 and IL-10 are involved in the pathogenesis of AIDS-associated large cell and mixed immunophenotype lymphoma.

Epstein-Barr virus as an agent of haematological disease

Epstein-Barr virus (EBV) encodes genes that permit its persistence in human B lymphocytes and genes that ensure its replication in epithelial cells. Immune restraints on the virus are usually so effective that most EBV infections are limited to a minute fraction of B lymphocytes and of epithelial cells. As a result, most EBV infections are never symptomatic. Occasionally, the virus causes disease, often with the cooperation of the immune system or other less characterized cofactors. Infectious mononucleosis, a generally self-limited lymphoproliferative illness common in adolescents and young adults, is due to primary EBV infection and to the brisk cellular immune response it elicits. Lymphoproliferative disorders of EBV-infected B cells arise almost exclusively when cellular immunity is grossly compromised. EBV-positive Burkitt's lymphoma contain a translocated and deregulated c-myc oncogene and EBV-positive non-Hodgkin's lymphomas are characterized by the presence of Reed-Sternberg's and Hodgkin's cells, features that have not been directly linked to EBV. Many recent observations, however, including evidence that virus infection precedes malignant transformation and is often associated with a characteristic pattern of viral gene expression, provide continued interest in the relationship between the virus and these haematological malignancies.

Epstein-Barr virus-associated non-Hodgkin's lymphoma in HIV-infected patients

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of many lymphoproliferations arising in diverse settings, including HIV-infection. The precise roles of EBV may differ between these settings. For example, both the frequencies of EBV-association and the specific c-MYC translocations differ between sporadic and African Burkitt's lymphoma. Similarly, the frequencies of EBV-association in HIV-infected patients differs between anatomical sites, types of NHL, and geographic locations. HIV-related NHL have genetic alterations similar to NHL arising in the general population, and have less in common with the lymphoproliferations which arise in the setting of transplantation. However, the patterns of latent EBV transcription in systemic HIV-related NHL is unique among NHL, suggesting that EBV may contribute differently to their pathogenesis.

HIV-associated lymphoma of the gastrointestinal tract: the University of Toronto AIDS-Lymphoma Study Group experience

We present a retrospective analysis of 31 (30 male) patients with HIV-associated gastrointestinal lymphoma which was undertaken to determine the natural history and response to therapy. Only seven patients had stage I or II lymphoma and 22 had stage IV. Pathology included diffuse large cell (13), immunoblastic (10), and small cell non-cleaved (7). The median age at presentation was 39 years (range 24-59), and the median CD4 count before treatment was 100/microL (range 4-1150). Eighty-seven percent of patients received systemic chemotherapy and significant response was seen in 84% (CR 38%; PR 46%). Hematologic toxicity was high (febrile neutropenia in 44% and dose reductions were required in 81%) and perforation occurred in five patients. Median survival for all patients was 6 months and death was secondary to lymphoma in 61%, treatment toxicity in 10%, other AIDS-related illnesses in 25% and other causes in 4%. Survival was shorter for patients with bone marrow involvement and for those with poor performance status. HIV-associated GI lymphoma has a poor prognosis despite good initial response to chemotherapy and is associated with a higher perforation rate than in HIV negative patients.

Malignant lymphoproliferative diseases in HIV-seropositive patients. A study of 40 cases at a single institution in Spain

We identified 40 patients with malignant lymphoproliferative diseases (MLD) and HIV infection (seropositive) at a single Spanish university hospital. Thirty-two patients had non-Hodgkin's lymphoma (NHL), 6 primary central nervous system lymphoma (PCL) and 8 patients Hodgkin's disease (HD). Median age at presentation was 32 years. Four histopathological groups had distinct presenting clinical features: in 93% of the Burkitt-type lymphomas, the lymphoma itself was the AIDS defining criterion, while high and intermediate grade NHL other than Burkitt-like tended to have a more advanced HIV infection, demonstrated by antecedent AIDS criteria in 58% of these patients and a median CD4 positive cell count of 291 mm3; HD occurred in some patients without previous opportunistic infections (7/8 patients) but with median CD4 cells of 105 mm3; PCL occurred in a terminal stage of HIV infection, in patients with a low performance status, and frequent antecedent AIDS criteria. Objective response to chemotherapy could be seen in 62% of NHL patients and 100% of HD. Survival was adversely related to an antecedent diagnosis of AIDS, low performance status, and a primary localization in the central nervous system. Overall median survival was 5 months, but patients without the mentioned three adverse prognostic factors had a median survival of 10 months.

In situ hybridization in neuropathology

In situ hybridization (ISH) allows the demonstration and localization of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in tissue sections, cells and chromosomes by utilizing a specific interaction with a labelled nucleotide probe of known composition. Although this technique has been employed for many years using radiolabelled probes, the recent development of nonisotopic labelling systems and the greatly increased availability of synthetic nucleic acids has allowed an enormous expansion in the potential applications of ISH. The technique is now applicable to unfixed and fixed tissues, including archival material. The use of enzyme-linked antibody techniques to detect labelled probes has greatly increased the sensitivity of non-isotopic ISH without a loss of specificity. The successful use of ISH demands careful selection of labelled probes, adequate tissue pretreatment to allow access of the probe, control of the stringency of probe binding and a sensitive reporter system, in addition to adequate controls. The accurate localization of nucleotides in the central nervous system (CNS) has many current research applications in the study of gene expression in multiple sclerosis and other inflammatory disorders, and a wide range of neurodegenerative disorders, viral infections and neoplasms. The technique is of diagnostic value in viral disorders, particularly where multiple infections occur. The combination of non-isotopic ISH with immunocytochemistry electron microscopy and quantitative image analysis greatly increases its research potential, while the development of a related method, the in situ polymerase chain reaction, offers an additional opportunity for further enhancing the sensitivity of this technique.

Bone marrow one step fixation-decalcification in Lowy FMA solution: an immunohistological and in situ hybridization study

The immunoreactivity of paraffin embedded bone marrow biopsies (BMB) was studied following a one step 20-hour-fixation-decalcification in Lowy formalin mercuric chlorid acid solution which permits excellent histological stainings. Antibodies reactive with myeloid, megakaryocytic, erythroid cells, T and B lymphocytes, mastocytes and metastatic cells were compared. Nearly all antibodies working on paraffin sections were demonstrated on Lowy FMA fixed BMB. Special care was taken to define an optimal working dilution. Trypsinization was not necessary. A slide microwave pre-treatment appeared essential before testing CD20 L26, CD8, CD3, CD34, MB1 Kappa and Lambda antibodies. It was suitable for UCHL1, LN2, CD30 antibodies. The same fixative allowed an m RNA Kappa or Lambda in myeloma and EBER 1 EBV RNAs in HIV lymphoma visualization by in situ hybridization. The safety handling of the toxic mercuric chloride component is discussed.

Molecular pathology of AIDS-related lymphomas. Biologic aspects and clinicopathologic heterogeneity

A high frequency of lymphoma in human immunodeficiency virus-infected individuals has been reported since the outbreak of the acquired immunodeficiency syndrome (AIDS) epidemic in 1982. AIDS-associated non-Hodgkin's lymphoma (AIDS-NHL) is almost invariably derived from B cells and is classified as high- or intermediate-grade NHL, according to the working formulation. Two main histologic types are recognized, including small noncleaved cell lymphoma (SNCCL) and diffuse large cell lymphoma (DLCL). Pre-existing host factors putatively involved in lymphoma development include disrupted immunosurveillance, deregulated cytokine production, chronic antigen stimulation, and infection by Epstein-Barr virus (EBV). These alterations are associated with the development of multiple oligoclonal expansions which correspond to the clinical phase known as persistent generalized lymphadenopathy (PGL). The appearance of a true AIDS-NHL is characterized by the presence of a monoclonal B-cell population displaying several genetic lesions, including monoclonal EBV infection, c-MYC and BCL-6 rearrangements, RAS mutations, p53 inactivation, and 6q deletions. These genetic lesions cluster into two distinct molecular pathways, which specifically associate with the different histologic subtypes of AIDS-NHL, i.e., AIDS-SNCCL and AIDS-DLCL. The presence of distinct genetic pathways for AIDS-SNCCL and AIDS-DLCL correlate with a number of clinical features which distinguish these two groups of tumors, including differences in the age of onset, CD4 counts at the time of presentation, time elapsed since HIV infection, and clinical outcome.

Correlation between cytopathological results and in situ hybridisation on needle aspiration biopsies of suspected African Burkitt's lymphomas

Burkitt's lymphoma (BL) is a very high-incidence malignancy in sub-Saharan Africa, where it targets mainly young children. This lymphoma is closely associated with Epstein-Barr virus (EBV). Diagnosis of BL relies on clinical presentation as well as histological results obtained from biopsies. In this report, 66 new patients from Malawi (one of the southernmost African countries with high-incidence BL), suspected on clinical grounds to present with BL, had fine needle aspiration biopsies taken, smeared on slides and used for May-Grünwald Giemsa staining. Duplicate slides were independently assessed for EBV presence and expression by DNA-DNA and/or RNA-RNA in situ hybridisation (ISH), using respectively the repetitive viral BamHIW DNA fragment in a biotinylated probe and the small EBV-encoded RNA EBER I in a digoxigenin-labelled riboprobe. There was very good correlation between the various techniques in the diagnosis of the lymphomas, showing 67% of clinically suspect cases to be BL. Our report, presenting data on BL in Malawi, illustrates the usefulness of a simple aspiration biopsy in the diagnosis of this malignancy by Giemsa staining and also in both types of ISH.

DNA of lymphoma-associated herpesvirus (HVMF1) in SIV-infected monkeys (Macaca fascicularis) shows homologies to EBNA-1, -2 and -5 genes

We have characterized a new Epstein-Barr-virus(EBV)-like herpesvirus associated with lymphomas of SIV-infected cynomolgus (Macaca fascicularis) monkeys and propose that this virus is designated herpesvirus macaca fascicularis I (HVMFI). Genomic regions in HVMF1 of potential significance for tumor pathogenesis were analyzed by Southern blotting, PCR and sequencing, and compared with human EBV DNA. Virus from 7 SIV-associated lymphomas and one lymphoma-derived cell line were shown to share homology with the EBNA1- and EBNA2-coding regions of EBV, while some homology to EBV-LMP1 was detectable only at low-stringency hybridization. Homologous regions to the long internal repeat (IR1; BamHI W), the EBER1 and 2 and the latent origin of DNA replication (oriP) could also be demonstrated in HVMF1. These coding regions, except IR1, showed restriction-enzyme maps different from those of EBV. Sequencing of the EBNA5 homologous region of HVMF1 DNA, corresponding to exons W1 and W2, showed 65% homology to the EBV exons W1 and W2, and 80% to the whole region including the intron. Since EBNA5 has been reported to bind tumor-suppressor proteins p53 and Rb in vitro, the HVMF1 homology could be important for the lymphomagenic capacity of this monkey herpesvirus.

EBNA-2 upregulation of Epstein-Barr virus latency promoters and the cellular CD23 promoter utilizes a common targeting intermediate, CBF1

The EBNA-2 protein is essential for the establishment of a latent Epstein-Barr virus (EBV) infection and for B-cell immortalization. EBNA-2 functions as a transcriptional activator that modulates viral latency gene expression as well as the expression of cellular genes, including CD23. We recently demonstrated that EBNA-2 transactivation of the EBV latency C promoter (Cp) is dependent on an interaction with a cellular DNA-binding protein, CBF1, for promoter targeting. To determine whether targeting via CBF1 is a common mechanism for EBNA-2-mediated transactivation, we have examined the requirements for activation of the cellular CD23 promoter. Binding of CBF1 to a 192-bp mapped EBNA-2-responsive region located at position -85 bp to -277 bp upstream of the CD23 promoter was detected in electrophoretic mobility shift assays. The identity of the bound protein as CBF1 was established by showing that the bound complex was competed for by the CBF1 binding site from the EBV Cp, that the bound protein could be supershifted with a bacterially expressed fusion protein' containing amino acids 252 to 425 of EBNA-2 but was unable to interact with a non-CBF1-binding EBNA-2 mutant (WW323SR), and that in UV cross-linking experiments, the Cp CBF1 binding site and the CD23 probe bound proteins of the same size. The requirement for interaction with CBF1 was demonstrated in a transient cotransfection assay in which the multimerized 192-bp CD23 response region was transactivated by wild-type EBNA-2 but not by the WW323SR mutant. Reporter constructions carrying multimerized copies of the 192-bp CD23 response region or multimers of the CBF1 binding site from the CD23 promoter were significantly less responsive to EBNA-2 transactivation than equivalent constructions carrying a multimerized region from the Cp or multimers of the CBF1 binding site from the Cp. Direct binding and competition assays using 30-mer oligonucleotide probes representing the individual CBF1 binding sites indicated that CBF1 bound less efficiently to the CD23 promoter and the EBV LMP-1 promoter sites than to the Cp site. To investigate the basis for this difference, we synthesized a series of oligonucleotides carrying mutations across the CBF1 binding site and used these as competitors in electrophoretic mobility shift assays. The competition experiments indicated that a central core sequence, GTGGGAA, common to all known EBNA-2-responsive elements, is crucial for CBF1 binding. Flanking sequences on either side of this core influence the affinity for CBF1.(ABSTRACT TRUNCATED AT 400 WORDS)

bcl-2 proto-oncogene and Epstein-Barr virus latent membrane protein-1 expression in AIDS-related lymphoma

The expression of bcl-2 protein and Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1) was investigated in 18 cases of lymphoma occurring in the acquired immunodeficiency syndrome (AIDS). EBV small RNAs were detectable in tumour cells in all cases by in situ hybridization with EBER oligonucleotides. LMP-1 expression was detected in 61% of the cases, and 55% were positive for bcl-2. Dual expression of LMP-1 and bcl-2 was found in 8/18 (44%) cases, while five cases (28%) expressed either LMP-1 or bcl-2 and five expressed neither. Thus, there was an inconsistent relationship between the presence of EBV and the expression of bcl-2. One LMP-1 negative case was found to express bcl-2 in reactive lymphocytes but not in lymphoma cells. No clinical features were found to correlate statistically with LMP-1 or bcl-2 expression in the tumour cells. However, CD4 counts at diagnosis were significantly lower in bcl-2 positive cases (P < 0.05). The respective roles of EBV LMP-1 and the expression of bcl-2 in lymphogenesis in AIDS patients remains complex and is not yet fully understood.

Primary central nervous system malignant non-Hodgkin's lymphomas from HIV-infected and non-infected patients: expression of cellular surface proteins and Epstein-Barr viral markers

The increased incidence of primary central nervous system malignant non-Hodgkin's lymphomas (PCNSL) in HIV- and non-HIV-infected patients and the demonstration of Epstein-Barr virus (EBV) in these tumours may indicate relationships between PCNSL and EBV. Consequently expression of EBV-induced antigens and cellular markers were studied in 11 HIV-infected and seven non-infected patients by in situ hybridization (ISH) and immunocytochemistry in monoclonal B cell PCNSL. In HIV-infected patients EBV genome was present in 9/11 cases, LMP in 11/11 cases and EBNA2 in 10/11 cases. The expression of adhesion and activation molecules was low or absent. In HIV non-infected patients, EBV genome was present in 5/7 cases, with LMP in 4/7 cases. EBNA2 was never detected. All these lymphomas expressed LFA1beta. Whatever the population, no lytic cycle EBV markers were detected. Compared with other types of EBV lymphomas, our results suggest a different EBV latency state in primary B cell lymphomas of the CNS from HIV-infected or non-infected patients.

Epstein-Barr-encoded RNA in situ hybridization: diagnostic applications

Latent Epstein-Barr virus (EBV) infection is associated with a variety of malignancies and other diseases. Highly restricted viral antigen expression and low viral genome copy number in infected tissues impede conventional immunohistochemical or in situ hybridization approaches to the detection of virus in these tissues. In situ hybridization detection of two small but very abundant nuclear RNAs known as the EBERs serves as an alternative approach. The EBERs are stable over time and can be detected in all common fixatives. This technique facilitates characterization of the cellular locus of latent EBV infection in histologically complex tissues, such as Hodgkin's disease and angioimmunoblastic lymphadenopathy with dysproteinemia.

Radiotherapy of primary central nervous system lymphoma in patients with and without human immunodeficiency virus. Ten years of treatment experience at the University of California San Francisco

BACKGROUND

Classic human immunodeficiency virus (HIV) negative primary central nervous system lymphoma (PCNSL) is a relatively uncommon occurrence, whereas the incidence of HIV positive PCNSL has increased dramatically during the past 5 years. Between 2% and 6% of all patients with acquired immune deficiency syndrome (AIDS) will have PCNSL develop clinically, and as many as 11% will have PCNSL found at autopsy. In the United States, some of the earliest and most extensive experience with HIV positive PCNSL has occurred in San Francisco. This article reports on PCNSL in patients with and without HIV.

METHODS

Using our diagnosis-based computer retrieval system, we identified all patients treated with radiotherapy for PCNSL between January 1982 and January 1992 and reviewed their medical records. Population characteristics, risk factors and length of survival (LOS), were analyzed. Statistical methodology included the Cox proportional hazards model and Kaplan-Meier survival curves.

RESULTS

Fifty-six patients were identified with PCNSL, of which 41 were HIV positive and 15 were HIV negative. There was a fourfold increase in the total number of PCNSL cases during the time period 1987-1991 as compared with the preceding 5 years; these cases primarily were in the HIV positive group. The average Karnofsky performance score (KPS) in the HIV positive group was 50, whereas in the HIV negative group, the KPS was 35. However, the median LOS in the HIV positive group was 3 months, whereas in the HIV negative group it was 20 months. Within each group, there was a statistically significant correlation between KPS and LOS.

CONCLUSIONS

Patients with HIV and PCNSL have a much shorter median LOS than do patients with PCNSL but without HIV; however, the outcome for both groups is dismal. Randomized clinical trials are needed to determine which patients with HIV might benefit from more aggressive therapy and to determine the optimal choice and dosages of chemoradiation therapy for patients with PCNSL without HIV.

Epstein-Barr virus in gastric carcinoma with lymphoid stroma. Special reference to its detection by the polymerase chain reaction and in situ hybridization in 99 tumors, including a morphologic analysis

BACKGROUND

Gastric carcinoma with lymphoid stroma (GCLS) has been reported to have a more favorable prognosis than ordinary gastric carcinoma, however, the precise mechanism of the pathogenesis for GCLS remains unclear.

METHODS

The authors analyzed 99 GCLS in 94 patients for Epstein-Barr virus (EBV) sequences using polymerase chain reaction (PCR) and in situ hybridization (ISH); these were compared with 42 ordinary gastric carcinomas.

RESULTS

Two series of PCR showed 81 (82%) and 46 (47%) of the 99 GCLS to have EBV sequences, which were significantly higher compared with ordinary gastric carcinoma (50% and 9.5%, respectively). With ISH using thymine-thymine dimerized oligonucleotide probes corresponding to EBV-encoded small RNA 1 (EBER1), 82 (83%) of 99 GCLS showed clear, intense hybridization signals localized over the nuclei of the tumor cells, in contrast to only 4 (9.5%) of 42 ordinary carcinomas (P < 0.001). A comparative morphologic analysis of EBER1-positive and negative GCLS revealed that typical features of GCLS, such as mild cellular pleomorphism, rare mitoses, a marked degree of lymphoid stroma, and mild fibrosis, together with a lymphoid infiltration within the cancer cell nests were significantly more frequent in EBER1-positive GCLS.

CONCLUSIONS

More than 80% of GCLS were associated with EBV. The presence of EBV association in GCLS was characterized by the above morphologic features.

Malignant tumours in patients with HIV infection

One of the most important though somewhat neglected aspects of research in HIV infection concerns the development, clinicopathological characteristics, and treatment of malignant tumours in infected patients. With the improved survival of patients with AIDS owing to the better prevention and treatment of infectious complications there may well be an increase in AIDS related malignancies. This paper reviews the epidemiology, pathology, and treatment of malignant tumours in patients with HIV.

Alterations of the p53 gene in Epstein-Barr virus-associated immunodeficiency-related lymphomas

Mutations of the p53 tumor suppressor gene are among the most common genetic alterations found in many different human malignancies, including those of the colon, lung, and breast. Alterations in wild-type p53 lead to loss of the suppressor function and thus contribute to tumorigenesis. The potential role of p53 mutations in a sampling of B-cell lymphomas, the majority of which were associated with Epstein-Barr virus (EBV), was investigated. Twenty-six biopsy specimens from immunocompromised patients, including allograft recipients and patients with AIDS, Wiscott-Aldrich syndrome, and human T-cell leukemia virus type 1 infection, in comparison with three Burkitt lymphomas and four Burkitt lymphoma cell lines were analyzed. Mutation in p53 was detected in all four Burkitt lymphoma cell lines as well as the three Burkitt lymphoma biopsy specimens. In patients with AIDS, 5 of 10 lymphomas were EBV positive, and 1 had a mutation in p53. Mutation in p53 was not detected in 14 EBV-positive lymphomas which arose in transplant recipients. These data indicate that with the exception of Burkitt lymphomas, p53 mutations are not involved in the majority EBV-positive B-cell lymphomas which develop in immunocompromised patients.

High frequency of Epstein-Barr virus in Chinese peripheral T-cell lymphoma

Forty-two cases of Chinese T-cell lymphoma were studied for expression of Epstein-Barr virus (EBV) encoded RNA (EBER-1) and EBV latent membrane protein-1 (LMP-1) using in situ hybridization and immunohistochemistry, respectively. EBV was detected in tumour cells in 24/39 peripheral T-cell lymphomas (62%), comprising 18/27 pleomorphic, medium and large cell lymphomas (67%), 4/6 angioimmunoblastic lymphadenopathy-like lymphomas (67%), 2/2 Lennert's lymphomas, 0/2 anaplastic large cell lymphomas, and 0/2 T-zone lymphomas. EBV was not found in three T-lymphoblastic lymphomas. EBV was associated with 12/24 nodal (50%) compared with 12/15 extranodal (80%) peripheral T-cell lymphomas. In EBV positive nodal lymphomas, 9/12 cases (75%) contained less than 10% EBER positive tumour cells. In EBV positive extranodal lymphomas, 9/11 cases (82%) showed EBV gene expression in more than 50% of the tumour cells, and in five of these almost all tumour cells were positive. Lymphomas of the nasopharynx (mainly midline granuloma-type) showed EBER-1 expression in nearly all tumour cells. LMP-1 was detected in 19/23 EBER positive peripheral T-cell lymphomas (83%). Our results show that EBV is strongly associated with peripheral T-cell lymphomas in Chinese. An important role for the virus is suggested in lymphomas of the nasopharynx. The significance of EBV in T-cell lymphomas that contain only a minor population of virally infected tumour cells is currently unclear.

Detection of Eber-1 RNA in primary brain lymphomas in immunocompetent and immunocompromised patients

Tissue from primary central nervous system lymphoma (PCNSL) which developed in five patients with acquired immuno deficiency syndrome (AIDS), nine patients without immunodeficiency, and two Epstein-Barr virus (EBV)-positive control cell lines (B95-8 and Raji) were examined for the presence of EBER-1 RNA. The tissues were hybridized with digoxigenin-labeled sense or anti-sense EBER-1 riboprobes. In all five AIDS-related PCNSLs, strong hybridization signals were found with the EBER-1 anti-sense probe. Signals could be eliminated by preincubation of the tissues with RNase-A. Hybridization with the EBER-1 sense probe showed no signal. All PCNSLs from immunocompetent patients (five paraffin-embedded, four frozen) showed no hybridization signals with EBER-1 sense or antisense probe but good hybridization signals with probes to immunoglobulin kappa or lambda light chain indicating RNA preservation. The paraffin-embedded B95-8-positive control cell-line showed positive hybridization in most cells with the anti-sense EBER-1 probe, and up to one percent of the cells had a weak signal with the sense probe. Most Raji cells showed a uniform signal with the anti-sense EBER-1 probe only. We conclude that, PCNSLs that arise in AIDS patients are associated with latent EBV infections, whereas PCNSLs from immunocompetent patients are not indicating a probable role for EBV in pathogenesis of these tumors.

Lymphoma complicating immunodeficiency disorders

BACKGROUND

An increased incidence of lymphoma is seen in various types of immune deficiency or dysregulation, including congenital immune deficiency diseases, organ transplantation with iatrogenic immunosuppression, autoimmune disorders, endemic Burkitt's lymphoma, and AIDS-associated lymphoma.

RESULTS

The lymphomas seen in various immunodeficiency disorders share certain features. Thus, all consist of high-grade, B-cell tumors, with predilection for extranodal involvement, and short survival. However, certain biologic and clinical differences are also apparent. Thus, while the transplantation-associated lymphomas are uniformly associated with the Epstein-Barr Virus (EBV), this association is not seen in all systemic AIDS-related lymphomas, nor in all congenital immune deficiency disorders. Likewise, while c-myc activation has been described in certain types of HIV-related lymphomas, c-myc dysregulation has not been reported in association with organ transplantation.

CONCLUSIONS

The study of lymphomatous disease in various states of immune dysregulation may allow an understanding of the diverse pathogenic mechanisms operative in the development of malignant lymphoma in man.

Non-Hodgkin's lymphoma in four children infected with the human immunodeficiency virus. Association with Epstein-Barr Virus and treatment

BACKGROUND

Reports on lymphoid malignancy and its treatment in children infected with human immunodeficiency virus (HIV) are limited.

METHODS

Antibodies to Epstein-Barr virus (EBV) were detected by indirect immunofluorescence. DNA was extracted from peripheral blood lymphocytes or biopsy specimens. Polymerase chain reaction was run using primers for EBV. Reaction products underwent Southern blot analysis to confirm EBV specificity. Tumor clonality was assessed by immunohistochemistry and by Southern blot analysis of immunoglobulin heavy-chain and T-cell receptor beta-gene rearrangement.

RESULTS

Within 1 year, non-Hodgkin's lymphoma (NHL) was diagnosed in four children infected with HIV. All four were EBV-seropositive and had detectable EBV DNA in peripheral blood lymphocytes. The EBV-linked disorders lymphoid interstitial pneumonia and recurrent parotid enlargement preceded NHL in three and two of the children, respectively. In all four patients, NHL involved at one time the central nervous system (CNS). All three tested NHL tissues were positive for EBV DNA: A 12-week course of chemotherapy given to two children resulted in rapid tumor regression. One of these children experienced meningeal relapse and died 16 months after diagnosis. The other child, who in addition received local irradiation of the affected eye and who underwent surgical removal of the involved ovaries, has been in continuous remission for 20 months.

CONCLUSIONS

EBV-associated NHL may be seen more frequently in pediatric patients with HIV. Treatment protocols taking into account NHL propensity for the CNS in this age group need to be developed.

CD30 (Ki-1) positive anaplastic large cell lymphomas in individuals infected with the human immunodeficiency virus

BACKGROUND

CD30 (Ki-1) positive anaplastic large cell lymphoma (ALCL) has been only rarely described in HIV-positive patients.

METHODS

The clinicopathologic features of eight ALCLs occurring in four AIDS and four HIV-positive patients were investigated. The phenotype of each neoplasm was determined by immunohistochemical methods. In three cases fresh tissue was available for molecular analysis.

RESULTS

The ALCLs are a clinically heterogeneous group of T (4), B (1) and indeterminate (3) cell malignant lymphomas which presented in the skin (4), liver (1), lung (1), nasal cavity (1; also with bone marrow involvement) and peritoneal fluid (1). While most of the patients had aggressive disease, dying in a median of three months, two patients had either localized or regressing skin lesions. Molecular studies showed that two ALCLs, one of B cell and one of indeterminate cell lineage, contained clonal Epstein-Barr virus sequences. None of the ALCLs examined contained evidence of HTLV-1 or HIV integration nor did they exhibit c-myc or bcl-2 proto-oncogene rearrangements. No mutations or deletions of the p53 tumor suppressor gene were identified in the three cases studied.

CONCLUSIONS

HIV-related ALCL represents a clinically heterogeneous group of T cell, B cell and null cell malignant lymphomas, distinct from the previously described categories of AIDS-associated NHL, that may expand the spectrum of lymphoid neoplasms associated with HIV-infection. Identification and investigation of other cases of HIV-associated ALCL is important to determine the nature of the relationship between HIV infection and the development of ALCL.

Epstein-Barr virus subtype distribution in angioimmunoblastic lymphadenopathy

The tissues of 16 patients bearing a T-cell lymphoma of angioimmunoblastic lymphadenopathy type (AILD-TCL) were investigated for the distribution of Epstein-Barr virus (EBV) subtypes 1 and 2. EBV-association had been proven in these cases by polymerase chain reaction (PCR) for EBV-DNA, in situ hybridization (ISH) for EBV-encoded small nuclear RNAs (EBER) and immunohistology for EBV-encoded latent membrane protein (LMP). PCR and EBER-ISH produced mostly identical results, but some cases were positive with only one of the 2 methods employed. LMP was detected in a few large cells of 8/13 cases. Twelve cases were investigated for the distribution of EBV subtypes. One case contained EBV genome of subtype 2, 3 cases contained subtype 1 and 4 cases contained both subtypes. Four cases could not be typed. These findings suggest that in AILD, as in AIDS-associated lymphomas and lymphomas of the lethal midline granuloma type, subtype 2 of EBV may occur, perhaps in relation to an immunodysfunction developing progressively in these patients.

The Epstein-Barr virus immortalizing protein EBNA-2 is targeted to DNA by a cellular enhancer-binding protein

The Epstein-Barr virus nuclear antigen EBNA-2 is essential for Epstein-Barr virus-induced immortalization of B cells. EBNA-2 is a transcriptional activator capable of modifying the expression of specific viral and cellular genes. However, the mechanism of EBNA-2 transactivation has been an enigma. We used a fractionated extract of CA46 lymphoblastoid cells and bacterially expressed EBNA-2 polypeptides to demonstrate that EBNA-2 is targeted to the Epstein-Barr virus latency C promoter (Cp) through interaction with a cellular DNA binding protein designated Cp binding factor 1 (CBF1). A glutathione S-transferase-EBNA-2 fusion protein containing aa 252-425 of EBNA-2 interacted with CBF1 to yield a slowly migrating complex in an electrophoretic mobility shift assay. Mutation of EBNA-2 aa 323 and 324, which lie within a highly conserved amino acid motif, abolished the interaction with CBF1. This same mutation also abolished the ability of EBNA-2 to activate the Cp in a cotransfection assay. The binding site for CBF1 was localized to residues -359 to -388 of the Cp by using an electrophoretic mobility shift assay and DNase I footprinting. Introduction of multiple copies of the CBF1 binding site upstream of a minimal heterologous promoter conferred EBNA-2 responsiveness on that promoter. Mutation of a core sequence CNGTGGGAA abolished CBF1 binding, and the mutated sequence was unable to mediate EBNA-2 transactivation. The CBF1 core sequence also occurs in other EBNA-2-responsive promoters suggesting that CBF1 may mediate EBNA-2 transactivation of both cellular and viral targets.

Epstein-Barr virus related gastric cancer in Japan: a molecular patho-epidemiological study

Epstein-Barr virus (EBV) involvement in gastric carcinoma has been demonstrated by the presence of EBV genomes and EBV-encoded small RNA (EBER) in the carcinoma cells, monoclonal proliferation of EBV-infected carcinoma cells and elevated antibody titers. The present study was conducted to investigate the prevalence of EBV involvement among gastric carcinomas observed in nine Japanese cities with varying gastric cancer rates. In situ hybridization of EBER-1 was applied to paraffin sections from 1848 carcinomas observed in 1795 cases and EBV involvement was detected based on uniform hybridization in carcinoma cells. Epstein-Barr virus was detected in 6.6% of lesions and 6.7% of cases. The rate of EBV involvement did not vary significantly for each city and there was no correlation with underlying gastric cancer mortality rates. Thus, geographic variation of gastric cancer rates within Japan cannot be explained in terms of EBV involvement. Epstein-Barr virus-related gastric carcinoma is one of the most common EBV-related tumors in Japan. The involvement of EBV was significantly more frequent among males than among females, mainly for cancers occurring in the upper and middle part of the stomach, and exhibited more variation by cell type among males. These observations suggest that other factors yet to be discovered may modulate the causal role of EBV in gastric carcinogenesis.

Epstein-Barr virus DNA in cerebrospinal fluid from patients with AIDS-related primary lymphoma of the central nervous system

Epstein-Barr virus (EBV) is constantly associated with AIDS-related primary lymphomas of the central nervous system (CNS). To assess whether EBV DNA in cerebrospinal fluid (CSF) could be used as a tumour marker, CSF samples that had been taken within 180 days before death from 85 patients with HIV infection and neurological disorders at necropsy were examined retrospectively by nested polymerase chain reaction (PCR) for EBV. Histologically evident primary CNS lymphomas were found in 17 patients, and EBV was shown in tissue by in-situ hybridisation in 16 of the 16 cases examined. All 17 patients with primary CNS lymphoma had EBV DNA in CSF. EBV DNA was found in CSF from 1 of 68 HIV-infected patients without histologically detectable lymphoma at necropsy. PCR for EBV DNA in CSF was 100% sensitive and 98.5% specific for AIDS-associated primary CNS lymphoma, and may be useful as a diagnostic tumour marker.

Epstein-Barr virus infection in HIV-positive patients

The relationship between Epstein-Barr virus (EBV) viral load in peripheral blood and HIV infection was determined in 103 HIV-infected patients. Epstein-Barr virus was detected by polymerase chain reaction in 75% of the patients, 21% of whom had the more uncommon EBV subtype 2. The highest levels of EBV were found in patients with 100-400 CD4+ cells/mm3 and not in those with more profound immunosuppression. An association was identified between EBV load and HIV proviral levels (p < 0.001), an IgM response to EBV early antigens (p < or = 0.01) and p24 antigenemia (p < 0.01 in patients with > 100 CD4+ cells), but not with other clinical or laboratory parameters. Combinations of different EBV and HIV parameters identified a subgroup of patients with a 2.2- to 4.8-fold risk of > or = 35% decline in CD4+ counts over six months. The association between EBV and HIV markers may reflect a significant pathogenic interaction between the two viruses.

Cutaneous anaplastic T-cell lymphoma in a patient with human immunodeficiency virus infection: detection of Epstein-Barr virus DNA

The Epstein-Barr virus (EBV) genome exists in tumour cells of T-cell lymphomas in non-immunosuppressed patients. We identified EBV-DNA by in situ hybridization in a case of anaplastic T-cell lymphoma associated with acquired immunodeficiency syndrome (AIDS). EBV-DNA has been reported in AIDS-related Hodgkin's disease or B-cell lymphoma, but never in T-cell lymphoma. Although our results suggest that EBV could play a role in the development of these anaplastic T-cell lymphomas, the mechanism of EBV penetration into T-cells remains uncertain.

EBNA-2 of herpesvirus papio diverges significantly from the type A and type B EBNA-2 proteins of Epstein-Barr virus but retains an efficient transactivation domain with a conserved hydrophobic motif

EBNA-2 contributes to the establishment of Epstein-Barr virus (EBV) latency in B cells and to the resultant alterations in B-cell growth pattern by up-regulating expression from specific viral and cellular promoters. We have taken a comparative approach toward characterizing functional domains within EBNA-2. To this end, we have cloned and sequenced the EBNA-2 gene from the closely related baboon virus herpesvirus papio (HVP). All human EBV isolates have either a type A or type B EBNA-2 gene. However, the HVP EBNA-2 gene falls into neither the type A category nor the type B category, suggesting that the separation into these two subtypes may have been a recent evolutionary event. Comparison of the predicted amino acid sequences indicates 37% amino acid identity with EBV type A EBNA-2 and 35% amino acid identity with type B EBNA-2. To define the domains of EBNA-2 required for transcriptional activation, the DNA binding domain of the GAL4 protein was fused to overlapping segments of EBV EBNA-2. This approach identified a 40-amino-acid (40-aa) EBNA-2 activation domain located between aa 437 and 477. Transactivation ability was completely lost when the amino-terminal boundary of this domain was moved to aa 441, indicating that the motif at aa 437 to 440, Pro-Ile-Leu-Phe, contains residues critical for function. The aa 437 boundary identified in these experiments coincides precisely with a block of conserved sequences in HVP EBNA-2, and the comparable carboxy-terminal region of HVP EBNA-2 also functioned as a strong transcriptional activation domain when fused to the Gal4(1-147) protein. The EBV and HVP EBNA-2 activation domains share a mixed proline-rich, negatively charged character with a striking conservation of positionally equivalent hydrophobic residues. The importance of the individual amino acids making up the Pro-Ile-Leu-Phe motif was examined by mutagenesis. Any alteration of these residues was found to reduce transactivation efficiency, with changes at the Pro-437 and Phe-440 positions producing the most deleterious effects. Activation of the EBV latency C promoter by EBNA-2 was shown to be dependent on the presence of the carboxy-terminal activation domain. However, this requirement was generic, rather than specific, since the EBNA-2 activation domain could be replaced with those from the herpes simplex virus (HSV) VP16 protein or the EBV Rta protein. Potential karyophilic signals within EBNA-2 were examined by introducing oligonucleotides encoding positively charged amino acid groupings that might serve in this capacity into a cytoplasmic test protein, HSV delta IE175, and by examining the intracellular localization of the resulting proteins. This assay identified a strong nuclear localization signal between EBV amino acids (aa) 478 to 485, which was conserved in HVP, and a weaker noncanonical signal between EBV aa 341 to 355, which was not conserved in HVP.

Complex nature of the major viral polyadenylated transcripts in Epstein-Barr virus-associated tumors

The most abundant polyadenylated viral transcripts in the Epstein-Barr virus (EBV)-associated tumor nasopharyngeal carcinoma are a family (apparent sizes, 4.8, 5.2, 6.2, and 7.0 kb) of highly spliced cytoplasmic RNAs expressed from the BamHI-I and -A regions of the viral genome in an antisense direction with respect to several viral lytic functions encoded within the same region and concerned with the lytic cycle of the virus. We have called these complementary-strand transcripts. They are also expressed in B cells, including Burkitt's lymphoma and EBV-immortalized marmoset cell lines, and tumors generated in cottontop tamarins in response to EBV infection, but at a lower level. The complete structure of the major 4.8-kb RNAs (seven or eight exons) was determined in this study; the larger, but related, transcripts appear to be produced by differential splicing. The transcriptional promoter for the major complementary-strand transcripts, located in BamHI-I, contains several well-characterized transcriptional control elements (E2A, SP1, and AP1) and is functionally active in both B lymphocytes and epithelial cells. It appears to be a bifunctional viral promoter, as it also contains the initiation codon for a gene (BILF2) that encodes a glycoprotein that is expressed off the other strand. Splicing events create a number of small AUG-initiated open reading frames, one of which has homology to functionally significant regions of the EBV-encoded nuclear antigen 2 and to E2 (in papillomavirus). The complex nature of these transcripts and their potential role in the virus association with malignancy are considered.

Epstein-Barr virus (EBV) in enteropathy-associated T-cell lymphoma (EATL)

Using Southern hybridization analysis, we have detected the Epstein-Barr virus (EBV) genome in 36 per cent (4/11) of enteropathy-associated T-cell lymphoma (EATL), a frequency much higher than that seen in nodal T-cell lymphomas in which we were able to show EBV DNA in only 3 per cent (1/30) of the cases examined. Using a terminal fragment probe, monoclonal proliferation of EBV in infected cells was demonstrated in three of the four EBV-positive EATL cases (in one case, insufficient signal prevented the determination of EBV clonality). The EBV genome and an early transcript, EBER1, were identified in tumour cells by in situ hybridization. Expression of latent membrane protein (LMP) was detected in two EBV DNA/RNA-positive EATL cases. In view of the known oncogenic properties of EBV and the putative central role of LMP in EBV-induced cell immortalization, the results of this study suggest that the virus may play an aetiological role in the pathogenesis of EATL.

Treatment of human immunodeficiency virus-associated Hodgkin disease. Is there a clue regarding the cause of Hodgkin disease?

BACKGROUND

The occurrence of human immunodeficiency virus (HIV)-associated Hodgkin disease (HD) offers a unique opportunity to study the cause of HD and compare HIV-HD with the well-characterized HIV-non-Hodgkin lymphoma (NHL).

METHODS

Eight patients with HIV-HD and 17 with HIV-NHL were treated.

RESULTS

The complete remission (CR) rate in HIV-HD was 100% with mechlorethamine, vincristine, procarbazine, and prednisone or doxorubicin, bleomycin, vinblastine, and dacarbazine (median survival, > 38.0 months). HIV-NHL patients were treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CR, 80%; median survival, 13.0 +/- 1.3 months). Durable CR was achieved with one to six cycles of chemotherapy (median, 4). There were no late relapses. The difference between the survival rate associated with chemotherapy-treated HIV-HD and chemotherapy-treated HIV-NHL approached statistical significance (P = 0.06). Analysis indicated that all patients with HIV-HD (n = 8) may have acquired HIV through intravenous drug abuse (IVDA) compared with 1 of 17 patients with HIV-NHL (P = 0.0001). A combined analysis (metaanalysis) of 157 patients with chemotherapy-treated HIV-NHL and 51 with chemotherapy-treated HIV-HD confirmed the significantly better survival of those with HIV-HD (P < 0.0001).

CONCLUSIONS

Standard combination chemotherapy, truncated as necessary, offers survival outcomes that are at least equivalent and, perhaps, superior to previously published experimental approaches for HIV-NHL and HIV-HD. HIV-HD has a significantly better prognosis than HIV-NHL and is associated with IVDA. These data suggest that the etiologic agents of HIV-HD and HIV-NHL may be transmissible, identifiable, and unique.

Epstein-Barr virus in Hodgkin disease. Relation to age and subtype

BACKGROUND

Epstein-Barr virus (EBV) has been associated with Hodgkin disease (HD), but its relationship to the age of the patients and the histologic subtype is not well defined. The possibility that other lymphotropic herpesviruses, such as cytomegalovirus (CMV) and human herpesvirus type 6 (HHV-6) could be involved in the pathogenesis of HD is also unclear.

METHODS

Paraffin-embedded material from 77 cases of HD was studied. This consisted of 24 specimens from children (mean age, 11.4 years), 36 from young adults (mean age, 28.8 years), and 17 from older adults (mean age, 53.8 years). EBV was detected in Hodgkin and Reed-Sternberg cells (HR-S) by a sensitive in situ hybridization technique based on the detection of Epstein-Barr-encoded RNA. Viral activity was subsequently demonstrated in HR-S cells by using monoclonal antibodies to EBV latent membrane protein.

RESULTS

EBV was found in a total of 25 of 77 cases (32%). There was no significant difference in EBV positivity between the different age groups. However, the prevalence of EBV varied between different subtypes: 68% of mixed cellularity cases were found to be positive by contrast with 24% nodular sclerosis, 0% lymphocyte predominant, and 14% lymphocyte depleted. Analysis of the histologic reports of a further 783 cases of HD to determine the age distribution of the different subtypes revealed an absence of an older adult second peak in the age distribution curve. In situ hybridization for CMV and HHV-6 was negative in all cases.

CONCLUSIONS

It was concluded that EBV is predominantly associated with mixed cellularity HD, and there is no correlation with the age of the patient.

The neurologic complications of human immunodeficiency virus infection

The physician caring for HIV-1-infected patients must have a good working knowledge of the broad spectrum of neurologic diseases that occur in association with this infection. As with any other neurologic disorder, the site of the neuraxis that is affected must be properly identified. In HIV-1-infected persons, more than one site may be involved simultaneously, such as the coexistence of myelopathy and peripheral neuropathy, often resulting in a confusing array of neurologic signs and symptoms. The frequent occurrence of two or more diseases affecting the neuraxis, such as progressive multifocal leukoencephalopathy and toxoplasmosis, further complicates the picture. With the AIDS patient, the physician cannot rely on the clinical adage that all attempts should be made to ascribe the patient's problems to one disease. Often, it is not the case. As with other illnesses, the approach to the HIV-1-infected person with neurologic disease needs to be thorough and fluid. After rendering a diagnosis and embarking on therapy, the physician needs to be open minded about the possibility of an incorrect or additional diagnosis not previously considered. Lastly, despite all the knowledge that has been accumulated in the first decade of the AIDS epidemic, new illnesses occurring with HIV-1 infection are recognized with regularity. The physician must always bear in mind that the illness with which he or she is confronted may be one that has not been previously described.

Comparison of polymerase chain reaction and standard Southern blotting for the detection of Epstein-Barr virus DNA in various biopsy specimens

The sensitivity of the polymerase chain reaction (PCR) assay was compared to that of standard Southern blotting (SB) hybridization for detecting the presence of Epstein-Barr virus (EBV) genomes in biopsy samples from 43 patients with a variety of lymphoproliferative disorders. Two pairs of oligonucleotide primers from the first BamHI M and R leftward reading frames (BMLF1 and BRLF1) of EBV were chosen to amplify DNA. The resulting PCR products were analyzed by gel electrophoresis, transfer and hybridization. Restriction enzyme digestion was used to confirm the specificity of the amplified fragment. EBV DNA was found in 38 of 43 patients, as compared with 9 of 43 patients with the Southern technique. No amplified product was detected with other viruses from the Herpes family, nor with human genomic DNA from healthy adults using the same two sets of primers. These results indicate that EBV can be detected in a greater number of lymphoproliferative lesions than previously appreciated. The implications of these findings are discussed.