Detection of Epstein-Barr virus in CNS lymphomas by in-situ hybridization

HIV-associated neurological disorders: a guide to pharmacotherapy

In the era of highly active antiretroviral therapy (HAART), HIV-1-associated neurocognitive disorder (HAND) continues to be a common and significant morbidity among individuals infected with HIV. The term HAND encompasses a spectrum of progressively severe CNS involvement, ranging from asymptomatic neurocognitive impairment and minor neurocognitive disorder through to the most severe form of HIV-associated dementia (HAD). While the incidence of HAD has declined significantly with HAART, the milder forms of HAND persist. In addition, HAND now develops in individuals with less advanced immunosuppression. The reasons for the persistence of milder forms of HAND in individuals treated with HAART are not entirely known. There are several hypotheses to explain this phenomenon that include the legacy effect, a failure of antiretroviral agents to reverse neurological damage, poor access of antiretroviral agents to the CNS, chronic systemic immune activation associated with microbial translocation products, sustained CNS inflammation, the improved survival of HIV-seropositive individuals and the possible contribution from aging, amyloid deposition and other co-morbidities. In contrast, the incidence of HIV-associated CNS opportunistic processes including progressive multifocal leukoencephalopathy, tuberculosis, CNS toxoplasmosis, cytomegalovirus encephalitis, cryptococcosis and primary CNS lymphoma has declined dramatically with the introduction of HAART. This review briefly summarizes our current understanding of HAND and the pathological mechanisms involved, namely direct injury from HIV-1 and viral proteins, indirect neurotoxicity from proinflammatory cytokines and chronic, sustained immune activation in the CNS. To date, only HAART has been shown to benefit HAND despite numerous controlled trials of adjunctive 'anti-inflammatory' agents. Although HAART has a profound impact on the incidence and severity of HAND, there exists a 'therapeutic gap' as even HAART that is effective at inducing durable virological suppression may only partially reverse HAND. In addition, there may be potential CNS adverse effects of antiretroviral agents. There is an ongoing multicentre clinical trial to investigate the role of the CNS Penetration-Effectiveness index, an indicator of drug permeability and availability in the CNS, to help guide the choice of antiretroviral agents in the treatment of HAND. With recent recommendations for earlier treatment intervention with HAART for HIV-1 infection, it remains to be seen the effects of this on HAND. There is an urgent need to better define the therapeutic guidelines for the prevention and treatment of HAND.

Epstein-Barr virus-associated primary central nervous system lymphoma in the Japanese population

The incidence of Epstein-Barr virus (EBV)-associated primary central nervous system (CNS) lymphoma in Japan was assessed using in situ hybridization of EBV-encoded small ribonucleic acid-1 (EBER-1) to identify the presence of EBV in 22 cases of formalin-fixed and paraffin-embedded primary CNS lymphoma. All cases were B-cell lymphoma. EBER-1 expression was observed in the nuclei of 3 of 22 primary CNS lymphoma cases (13.6%). The incidence of EBV-positive lymphoma in Japanese cases is higher than previously reported from Western countries. Patients with EBV-positive primary CNS lymphoma showed shorter survival than those with negative tumors (median 4 months vs. 26 months). EBER-1 in situ hybridization for the detection of EBV infection is rapid and reliable. Infrequent association suggests a different pathogenetic mechanism in the evolution of these tumors. Geographical differences in the incidence of EBV-associated primary CNS lymphoma may reflect epidemiological factors.

[Physiopathogenic aspects of HIV-associated primary brain lymphomas]

HIV-associated Primary brain lymphomas (PBLs) are usually diffuse, large B-cell lymphomas (DLBCLs). In contrast to those occurring in immunocompetent patients, nearly all HIV-associated PBLs are associated with Epstein-Barr virus (EBV). Since viral latency proteins are target antigens for anti-viral cytotoxic T lymphocytes, the double immunodeficiency (HIV infection, central nervous system microenvironment) favors the expression of viral latency proteins (LMP-1, EBNA2). These proteins play a major role in immortalization and transformation of infected B lymphocytes through cell cycle activation and apoptosis inhibition.

Neoplastic masquerade syndromes

Masquerade syndromes are classically defined as entities which emulate inflammatory conditions but which are in fact due to a neoplastic process. Careful history and examination in concert with appropriate ancillary investigations and histopathologic evaluation of tissue specimens are required in order to make the correct diagnosis. Many conditions may result in an appearance mimicking an inflammatory condition. The authors review neoplastic conditions which may be considered masquerades. The most common of these is primary intraocular lymphoma or primary central nervous system lymphoma, occurring predominately in older individuals. Diagnostic strategies, therapy, and prognosis are reviewed in detail. Other conditions that can be considered masquerade syndromes are reviewed as well, including lymphomatous and nonlymphomatous conditions, such as melanoma, retinoblastoma, juvenile xanthogranuloma, metastatic lesions, and paraneoplastic syndromes, among others.

Persistent preceding focal neurologic deficits in children with chronic Epstein-Barr virus encephalitis

Epstein-Barr virus encephalitis is a self-limiting disease with few sequelae. Persistence of neurologic deficits prior to and after the acute illness has yet to be described in children. We describe five children with persistent cognitive and focal neurologic deficits due to chronic Epstein-Barr virus encephalitis with various T2-weighted magnetic resonance imaging abnormalities. Clinical features were a 9-year-old boy with aphasia and apraxia, an 11-year-old girl with impulsivity and inappropriate behavior, a 17-year-old boy with deterioration of cognitive skills and judgment, a 5-year-old boy with complex-partial seizures, and a 6-year-old girl with obsessive-compulsive behavior. All patients had elevated serum Epstein-Barr virus titers for acute infection, with cerebrospinal fluid polymerase chain reaction positive for Epstein-Barr virus in four patients. Three children were treated with methylprednisolone with minimal improvement without changes on magnetic resonance imaging. Epstein-Barr virus encephalitis can present with chronic and insidious neurologic symptoms and should be considered in the differential diagnosis of children with acute or chronic neurologic illness of unknown etiology.

Primary central nervous system lymphoma

Primary central nervous system (CNS) lymphoma is an unusual but increasingly frequent brain tumor being identified by neurologists. Considerable improvements in survival have been accomplished by the addition of chemotherapy to cranial radiotherapy. In addition, many patients achieve substantial disease free survival with chemotherapy alone, and survival is superior to radiotherapy alone. Currently, every patient should be considered for chemotherapy as the first line of treatment. Subsequent cranial radiotherapy may or may not be necessary depending upon the patient's clinical condition, age and response to initial chemotherapy. Intensification of multi-agent chemotherapy is under study and it is anticipated that the incidence of neurotoxicity will reduce with elimination of combined modality treatment.

AIDS Primary Central Nervous System Lymphoma: Molecular Analysis of the Expressed VH Genes and Possible Implications for Lymphomagenesis

AIDS-associated primary central nervous system lymphomas are late events that have an extremely poor prognosis. Despite different hypotheses, the brain localization of these B cell lymphomas remains an enigma. To better define the cell origin of the lymphomas and the possible role of the B cell receptor (BCR) in the brain localization and/or in the oncogenic transformation, we analyzed the V region genes of the Ig heavy chain expressed by lymphoma cells in five randomly selected patients. After amplifying the rearranged VHDJH DNA by PCR, cloning, and sequencing of the amplified products, we observed that: 1) of the five lymphomas analyzed, four were clearly monoclonal; 2) there was no preferential use of one peculiar VH family or one peculiar segment of gene; 3) the mutation analysis showed that an Ag-driven process occurred in at least two cases, probably before the oncogenic event; and 4) there was no intraclonal variability, suggesting that the hypermutation mechanism is no longer efficient in these lymphoma B cells. Taken together, our results suggest that distinct Ags could be recognized by the BCR of the lymphoma cells in different patients and that, if the Ags are responsible for the brain localization of these B cells bearing mutated BCR, other factors must be involved in B cell transformations in primary central nervous system lymphoma.

Low-grade monoclonal Epstein-Barr virus-associated lymphoproliferative disorder of the brain presenting as human immunodeficiency virus-associated encephalopathy in a child with acquired immunodeficiency syndrome

The association of the Epstein-Barr virus with human immunodeficiency virus-associated primary central nervous system lymphomas is well known. We describe a pediatric patient infected with human immunodeficiency virus who developed a lesion in the central nervous system that appeared to be histologically reactive and that proved to be an Epstein-Barr virus-associated monoclonal B-cell lymphoproliferative disorder by molecular analysis. An 8-year-old girl was diagnosed with vertically transmitted human immunodeficiency virus infection at age 5, for which she was treated empirically with a combination of zidovudine and didanosine. At the age of 7 years, during evaluation for entry into an antiretroviral protocol, a single hypodense frontal lobe lesion was identified by computed tomography. After unsuccessful treatment for presumed toxoplasmosis and progressive neurologic deterioration, a stereotactic brain biopsy was performed. Although the biopsy contained a polymorphic lymphoid infiltrate that appeared to be cytologically reactive, polymerase chain reaction and in situ hybridization studies revealed a monoclonal Epstein-Barr virus-associated B-cell lymphoproliferative disorder, which was reminiscent of polymorphic B-cell hyperplasia observed in the setting of immunosuppression following organ transplantation. Postoperative therapy included steroids and antiretroviral therapy. The lesion decreased slightly in size, and the child's neurologic status was relatively unremarkable for 5 months. Subsequently, she developed cytomegalovirus retinitis, progressive encephalopathy, and died with pancytopenia. This case represents a newly described manifestation of Epstein-Barr virus-associated lymphoproliferative disorder, a diagnosis that should be considered in patients with neurologic symptoms and immunodeficiency. In addition, this case exhibited histologic features reminiscent of posttransplant lymphoproliferative disease, a histologic pattern that to our knowledge has not previously been reported in the setting of acquired immunodeficiency syndrome.

PCR ELISA for the quantitative detection of Epstein-Barr virus genome

A highly sensitive and nonradioactive microplate hybridization assay for the detection of Epstein-Barr virus (EBV)-specific polymerase chain reaction (PCR) product was developed. The PCR product is labelled by adding digoxigenin-dUTP directly to the reaction mixture and, after denaturation, is captured by a microtitre plate coated with an extravidin-linked biotinylated probe. Captured products are reacted with a peroxidase-conjugated anti-digoxigenin antibody and detected using tetramethylbenzidine. The assay detected less than ten EBV genomes in a background EBV-negative DNA of 0.75 microg and, when tested on clinical samples, it was able to define the viral load in throat washings of patients with acute infectious mononucleosis, immunosuppressed patients with HIV infection, and rare normal individuals who shed the virus in the oropharynx.

AIDS-related primary brain lymphomas: histopathologic and immunohistochemical study of 51 cases. The French Study Group for HIV-Associated Tumors

Fifty-one cases of acquired immunodeficiency syndrome (AIDS)-related primary brain lymphomas (AR-PBL) were investigated for clinical characteristics; human immunodeficiency virus (HIV)-associated disorders; histopathologic features; immunophenotype; Epstein-Barr virus (EBV) infection; and, when frozen tissue was available, oncogene rearrangements. AR-PBL occurred late in the course of AIDS and were usually associated with other systemic or cerebral disorders and with a low level of CD4 lymphocytes. All cases were high grade lymphomas according to the Working Formulation or updated Kiel classification, and often displayed a multifocal pattern. Thirty cases were classified as immunoblastic with plasmacytic differentiation, 18 cases were large cell lymphomas with an immunoblastic component or centroblastic polymorphic lymphomas, and 2 were small noncleaved non-Burkitt lymphomas (Working Formulation). This latter category is classified as Burkitt's-like lymphoma in the REAL nomenclature. One case could not be classified because of necrosis. AR-PBL showed a high level expression of activation and adhesion molecules. The presence of EBV was detected in most cases, and, when PCR was used, this was a constant finding. bcl-2 oncoprotein and latent membrane protein-1 (LMP-1) were strongly expressed. None of the tested cases expressed p53, or were rearranged for bcl-2 or c-myc oncogenes. This study confirms the immunophenotypic specificity of AR-PBL, which may reflect the special immune status of the brain.

Primary cerebral non-Hodgkin's lymphoma (PCNSL): a review of new trends in management

Primary central nervous system lymphoma (PCNSL) is a rare tumor but it is rising in incidence in both AIDS and non AIDS populations. It is a non-Hodgkin's lymphoma that usually presents itself as a brain tumor, but leptomeninges, eyes and also spinal cord are frequently affected. The management of PCNSL patients has evolved in the last years. The role of surgery has been restricted for diagnosis only because the exeresis of the tumor is ineffective owing to its multifocal and infiltrative nature. Therefore, stereotactic biopsy is the way of choice for documenting the diagnosis. The standard treatment was radiotherapy started after diagnosis and followed by chemotherapy at recurrence. PCNSL is radiosensitive and chemosensitive: about 70% of patients respond to one or other of these treatment modalities but usually PCNSL recurs locally after radiotherapy. More recently the inclusion of high doses ARA-C and Methotrexate delivered prior radiotherapy have shown significant high responses and prolonged survivals.

Pediatric HIV infection

Developments in the prevention and treatment of HIV infection in pregnant women and their children are encouraging. Perinatal ZDV therapy can reduce the maternal-infant transmission rate by two thirds in select populations. New therapies and the development of diagnostic assays to monitor HIV viral burden have renewed hope that, by aggressively controlling viremia, the progressive immunodeficiency can be delayed or even prevented. The general pediatric approach of preventing illnesses through aggressive vaccination and education policies must be actively incorporated into an approach to this epidemic. Success in controlling the pediatric HIV epidemic requires a concerted, coordinated effort by public policy makers, health care providers, basic science researchers, and those who are HIV-infected.

Neurologic manifestations of HIV infection

A wide spectrum of central and peripheral nervous system abnormalities may be associated with HIV infection. These disorders may be caused by HIV infection, result as secondary complications related to immunosuppression, or be a neurotoxic effect of therapeutic agents. The range of neurologic disorders includes dementia, focal cerebral mass lesions, myelopathy, peripheral neuropathies, and myopathy. Early diagnosis and therapy is critical, and may result in substantial improvement in patients' quality and quantity of life. This article reviews the approach to differential diagnosis of these neurologic disorders and presents theories of pathogenesis and current approaches to treatment.

Biology and management of AIDS-associated primary CNS lymphomas

Primary central nervous system (CNS) lymphoma is the most common brain tumor in patients with AIDS and occurs in about 10% of this population. CT/MR scan usually demonstrates single or multiple contrast enhancing masses that are radiographically indistinguishable from other CNS processes such as toxoplasmosis. Brain biopsy, positive cerebrospinal fluid (CSF) cytology, or possibly the demonstration of Epstein-Barr viral DNA in the CSF can establish the diagnosis. Cranial radiotherapy (RT) has been the cornerstone of therapy and produces responses in most patients, but their median survival is still only a few months. The addition of chemotherapy to RT may prolong survival in a sub-group of patients.

Cytomorphology of primary CNS lymphoma: review of 23 cases and evidence for the role of EBV

Primary non-Hodgkin's lymphoma of the central nervous system (PCNSL) has recently increased in incidence, due primarily to an enlarging immunosuppressed patient population. The pathogenetic role of Epstein-Barr virus (EBV) is of interest due to its established role in other lymphoproliferative disorders in immunosuppressed patients. Twenty-three cases of histologically confirmed PCNSL with corresponding cytology were identified, all obtained under stereotactic guidance. Twenty patients were human immunodeficiency virus (HIV) positive, two were HIV negative, and one was of unknown status. Papanicolaou-stained slides were selected from each case and evaluated for the presence of EBV RNA via in situ hybridization (ISH) utilizing a biotinylated probe specific for EBER 1 RNA, and detected by a conventional streptavidin-peroxidase system. The cases included immunoblastic (12), large cell (10), and mixed small and large cell lymphoma (1). The predominant immunophenotype was B-cell (19), although T-cell (2) and biphenotypic (1) cases were also identified. ISH showed nuclear positivity for EBV RNA in 19 of 23 cases (83%). This study confirms the presence of EBV in PCNSL in immunosuppressed patients and implies a potential etiologic role. The ability to demonstrate EBV RNA in cytologic preparations by ISH also raises the possibility of early identification of high-risk patients through detection of EBV-infected lymphocytes in CSF specimens.

Non-Hodgkin's lymphoma

Lymphoid neoplasia is a complex area comprising multiple diseases with varied pathology, treatment, and outcome. The non-Hodgkin's lymphomas are reviewed here. Non-Hodgkin's lymphomas, collectively, represent the sixth most common cancer in the United States as well as the sixth most common cause of cancer deaths. The overall incidence of non-Hodgkin's lymphoma has risen steadily over the past four decades. Although some of this is attributable to human immunodeficiency virus (HIV)-associated lymphoma, HIV-associated disease accounts for only a small part of the increase in lymphoma. As our knowledge of normal as well as neoplastic lymphoid development has expanded on the basis of histopathology as well as adjunct cellular and molecular techniques, multiple classifications have been proposed to take these into account. The clinical relevance to our understanding of non-Hodgkin's lymphoma is the concept that various lymphoid cancers are counterparts of stages of normal lymphoid development. Stages of lymphoid development in terms of cell surface markers and immunoglobulin gene rearrangements have been well characterized. These are particularly applicable to the early B-cell development, which is antigen-independent and occurs in the bone marrow. Diseases correlating with these stages are largely acute lymphocytic and lymphoblastic leukemia/lymphoma and high-grade lymphomas, such as Burkitt's lymphomas. Much has been learned recently about subsequent antigen-dependent B-cell development in secondary lymphoid organs to improve our understanding of the corresponding stages of B-cell neoplasia. Many of these stages correlate with more recently described entities such as mantle cell and marginal zone lymphomas. Histologic study remains crucial in determining the subtype of NHLs, whereas immunohistochemistry, surface phenotype, and molecular studies are useful in selected cases. Although some lymphoma classifications may be better in terms of understanding the lymphoma biology, the working formulation remains useful to guide clinical decision making. Lymphomas classified as low grade are considered incurable with standard therapy when diagnosed, as is usual, at advanced stages. Different subtypes may have different median survivals, but the goal has typically been palliation, whereas experimental approaches are clearly needed. Intermediate and high-grade lymphomas are potentially curable with aggressive combination chemotherapy. Recent evidence suggests that CHOP chemotherapy is as effective as more complex regimens. Still, 40% to 50% of patients are cured. Prognostic factor analysis has allowed separation of subgroups with much better survival in whom CHOP is adequate versus those with much poorer survival in whom experimental approaches are rational. Additional subtypes of lymphomas have been described and characterized since the working formulation was developed, including mucosa-associated lymphoid tissue tumors (MALT-oma), mantle zone lymphoma, anaplastic large cell lymphoma and AILD-like T-cell lymphoma. Approaches to these entities are still being optimized. Newer approaches, including high-dose therapy with stem cell support, biologic agents, and newer chemotherapeutic agents are discussed, as are special situations such as localized lymphoma of certain sites and lymphoma in immunosuppressed patients.

Pathogenesis and classification of primary central nervous system lymphoma: an update

Primary central nervous system lymphoma has undergone a remarkable increase in incidence over the last decade, both in immunosuppressed and immunocompetent individuals. Its clinicopathologic evaluation requires knowledge of current hematopathologic systems for lymphoma classification, as well as specific understanding of unique central nervous system determinants. In immunocompromised individuals, the tumor has a constant association with Epstein-Barr virus. The form of Epstein-Barr virus in these tumors appears to be predominantly latent, however, the precise mechanism relating virus to tumor pathogenesis is still unclear. In immunocompetent patients, risk factors and oncogenic associations are completely unknown. Critical to the formation of these tumors is the trafficking of B-cells, whether pre- or post-transformation, across the blood-brain barrier. These B-cell migrations may require perturbations to the barrier that originate in or around neural parenchyma, such as localized injury or infection.

The neuropathology and epidemiology of AIDS. A Berlin experience. A review of 200 cases

The brains of 200 patients who died with Acquired Immunodeficiency Syndrome (AIDS) from Berlin were examined retrospectively. This study was specifically intended to evaluate and document the prevalence of neuropathologic abnormalities, establishing the frequency of the various types of structural lesions, their combinations, their relative incidence, and the risk factors involved in different age groups. The data were compared and contrasted with the findings reported from other parts of the world and other German cities. It was found that the mean age of this group of patients was 41.4 years old, 75% were homosexual/bisexuals (H/B) and 18.5% were drug abusers (DA). Only 5.5% were women. Brain parenchymal changes, called in this report, HIV-related encephalopathy (HIVRE), characterized by vacuolization or spongy changes and astrocytosis in the subcortical white matter, and occasionally in gray matter, were found in 67 patients (33.5%). Drug abusers had a higher incidence of HIVRE (59.5%) compared with homosexual/bisexuals (28%). This is statistically significant (p < 0.0005). CMV encephalitis was found in 26 patients (13%) (8% of the drug abusers in contrast to 13% in the homosexual/bisexuals group). Primary central nervous system lymphoma (PCNSL) was seen in 28 patients (14%) regardless of the risk factor involved. 20 (13%) of the 150 H/B and 3 (8%) of the 37 DA had CMV encephalitis. Of the 150 H/B, 24 (16%) had PCNSL compared with only 4 of 37 (11%) of the DA. A significant incidence of opportunistic infections, both protozoal and viral was found in all groups. Cerebral toxoplasmosis occurred in 68 patients (34%). Microglial (phagocytic) nodules, probably related to CMV or cerebral Toxoplasmosis, were observed in 40 cases (20%). Diffuse microglial proliferation was noted in 104 patients (52%). Cerebral cryptococcosis was found in three patients. Progressive multifocal leukoencephalopathy was seen in 16 patients (8%). Various combinations of CNS pathological processes were found in 44 of the patients (22%). These include concomitant infections with Toxoplasma gondii and HIVRE in 13 patients; Toxoplasmosis and PCNSL in 8 patients; Toxoplasmosis with CMV and HIVRE in 4 patients; Toxoplasmosis with CMV in 2 patients; Toxoplasmosis with PCNSL and CMV in 2 patients; Toxoplasmosis with PCNSL and HIVRE in 2 patients and Toxoplasmosis with PML and HIVRE in 2 patients; Cerebral CMV with PCNSL and HIVRE in 4 patients; Cerebral CMV with HIVRE in 2 patients; PML with PCNSL in one patient; PML with HIVRE in 2 patients; and PML with PCNSL and HIVRE in one patient. Cerebrovascular lesions were found in 34 patients (17%).(ABSTRACT TRUNCATED AT 400 WORDS)

Diagnosis of Epstein-Barr virus-induced central nervous system infections by DNA amplification from cerebrospinal fluid

A nested polymerase chain reaction was used for the detection of Epstein-Barr virus DNA in 1 patient with encephalitis, and in 1 patient with myelitis. Epstein-Barr virus DNA was detected in cerebrospinal fluid samples obtained at the onset of neurological symptoms in both patients, and serological findings indicated ongoing Epstein-Barr virus infection. In the patient with encephalitis, herpes simplex virus type 1 DNA was transiently detected in the cerebrospinal fluid, while Epstein-Barr virus DNA was still present on day 44 after admittance. Single-photon emission computed tomography in this patient indicated a frontal bilateral hypoperfusion. The diagnostic value of polymerase chain reaction on cerebrospinal fluid and serum samples for Epstein-Barr virus infections of the central nervous system is emphasized.

Manifestations of Epstein-Barr virus-associated disorders in liver

Epstein-Barr virus is a ubiquitous virus associated with a variety of different diseases and disorders. The manifestations of Epstein-Barr virus-associated diseases or disorders within the liver, which involve a broad spectrum of histologic and clinical features, ranging from hepatitis through lymphoproliferative disorders to lymphoma, are presented. An important aspect of Epstein-Barr virus expression and infection is the biology of the Epstein-Barr virus. Documentation of infection can be performed using serology to detect the interaction of Epstein-Barr virus with the immune system, and the detection of EBV proteins and use of molecular biologic techniques to identify the presence of EBV RNA, and DNA sequences. Of particular utility are in situ hybridization, Southern blot analysis, and polymerase chain reaction as diagnostic methods to identify specific RNA or DNA sequences. Epstein-Barr virus-associated diseases and disorders including infectious mononucleosis, sporadic fatal infectious mononucleosis, X-linked proliferative disorder (Duncan's disease), post-transplant lymphoproliferative disorders, lymphoma, and AIDS are discussed. The histopathologic findings present in liver associated with each disease are presented with illustrative examples. Handling the tissue and interaction with clinical services are also discussed as a method for appropriate diagnosis of Epstein-Barr virus-driven processes affecting the liver.

Isolated cerebellar lymphomatoid granulomatosis progressing to malignant lymphoma. Case report

A 60-year-old man presented with progressive and unique neurological symptoms. Investigations identified an isolated cerebellar lesion. This lesion fulfilled the histological criteria for lymphomatoid granulomatosis, and in situ hybridization and deoxyribonucleic acid (DNA) dot blot techniques revealed significant amounts of Epstein-Barr virus DNA within the tumor cells. The patient underwent cranial radiation therapy, and 16 months after the initial presentation the lesion evolved into a malignant lymphoma. He subsequently died secondary to subdural empyema, bacterial meningitis, and bronchopneumonia. The unique clinical and etiological aspects of this case are addressed.

Primary central nervous system lymphomas. Immunophenotypic, virologic, and cytogenetic findings of three patients without immune defects

BACKGROUND

Primary central nervous system (PCNS) lymphoma is a relatively rare disease, but an increasing incidence is reported. The Epstein-Barr virus (EBV), which is often found in lymphomas of immunocompromised patients, has been implicated in the development of lymphomas. Many cytogenetic analyses of nodal B cell lymphomas have been performed, but few studies on PCNS lymphomas have been reported.

METHODS

The detection of EBV genome using the polymerase chain reaction (PCR) method and cytogenetic studies were performed, in addition to histopathologic and immunophenotypic approaches in biopsied tissue from three patients with PCNS lymphoma. Immunosuppressive states and exposure to mutagens were not clear in all patients.

RESULTS

Histopathologic examination disclosed a diffuse type of malignant lymphoma in all patients. Immunophenotypic studies revealed B cell phenotype in all patients, two of whom showed positive reaction for CD5. The PCR method revealed no involvement of EBV genome in tumors in any patients. The cytogenetic study showed clonal chromosome abnormalities in all patients, and abnormalities of chromosome 1 (1q21), 6 (-6, 6q15 and 6q21), 7 (-7 and 7p15), and 14 (14q24 and 14q32) were prominent. The t(6;14)(q15;q32) observed in Patient 1 is the first case to be reported in human de novo lymphoma.

CONCLUSIONS

These findings indicate that the causative role of EBV in PCNS lymphoma without immune defects is not clear. The cytogenetic findings were similar to those observed in nodal B-cell lymphoma, suggesting that the origin of PCNS lymphoma cells does not differ from nodal B cell lymphoma cells cytogenetically.

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.

Non-Hodgkin lymphomas of the central nervous system. Clinico-pathologic and immunohistochemical study of 147 cases

We report on data gathered from five European centres regarding 147 primary non-Hodgkin Lymphomas (NHLs) of the Central Nervous System (CNS) in HIV-negative patients. The results lead us to make the following considerations: i) there has been a significant and progressive increase in the frequency of observation of this pathology during the course of the last two decades; ii) the pathology lacks specific characteristic symptoms; iii) the radiological profile, as observed by CAT and/or MNR, most frequently corresponds to an isodense or slightly hyperdense lesion which has clear margins and is capable of assuming the contrast medium homogeneously; iv) the tumour most often has a single supratentorial localisation; v) high grade B-cell lymphomas account for 66% of the observations, low grade B-cell varieties being relatively rare and cases of T-cell derivation exceptional (6/147); vi) immunohistochemistry allows the differential diagnoses with respect to primitive or secondary non-lymphoid tumours, and provides confirmation of the histogenetic assessment made on morphological grounds; vii) the course of the disease is not significantly influenced by the histotype, the phenotype, the number of lesions present or the chemotherapy regimen, but rather by the employment of combined surgery and radio- or radiochemotherapy. This study represents the largest series of CNS NHLs so far reported, and as such, provides precise clinico-pathological indications which were only partially obtainable from the relatively small previously published series. Some concluding remarks are made as to the genesis of CNS NHLs, along with some practical suggestions for reaching a better understanding of their complex biology.

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.

The neuropathology of pediatric acquired immunodeficiency syndrome

Central nervous system disease has emerged as an important manifestation of acquired immunodeficiency syndrome in both the adult and pediatric populations, with neurologic abnormalities occurring in up to 90% of pediatric patients in some series. Neuropathologic studies, based primarily on the autopsy, have provided valuable insights into the spectrum and pathogenesis of acquired immunodeficiency syndrome-associated neurologic disorders, including primary human immunodeficiency virus encephalopathy and as the spectrum of infectious, neoplastic, and cerebrovascular diseases that may complicate the course of acquired immunodeficiency syndrome. Progressive encephalopathy represents the single most common neurologic disorder in pediatric acquired immunodeficiency syndrome and appears to be caused in most cases by direct infection in brain parenchyma by human immunodeficiency virus. Central nervous system lymphoma and cerebrovascular disease continue to account for most focal central nervous system lesions in the pediatric population. In contrast to adults with acquired immunodeficiency syndrome, opportunistic central nervous system infections remain relatively uncommon in the pediatric population. Our understanding of acquired immunodeficiency syndrome-associated neurologic disease remains far from complete. A plea is made for regular postmortem examination of the central nervous system in all patients dying with human immunodeficiency virus infection.

AIDS: Part II

Great strides have been made in the therapy of human immunodeficiency virus (HIV) infection. Currently approved drugs include zidovudine and didanosine. A third drug, dideoxycytidine (zalcitibine), has recently been filed for approval with the Food and Drug Administration. All these drugs work through inhibition of the reverse transcriptase enzyme. Zidovudine is the only drug that has shown clinical efficacy against HIV. Treatment of patients with advanced HIV disease (i.e., acquired immune deficiency syndrome [AIDS] or symptomatic infection with < 200 CD4+ lymphocytes per mm3), results in a prolongation and improved quality of life. Zidovudine is the only antiretroviral agent approved for the treatment of asymptomatic patients. Early intervention with zidovudine has been shown to delay progression to AIDS when patients' CD4+ lymphocyte counts decline to less than 500/mm3, irrespective of clinical signs or symptoms of HIV infection. Didanosine is currently indicated for the treatment of patients with advanced HIV disease who are intolerant to or failing zidovudine therapy. The major toxicity of zidovudine is bone marrow suppression with anemia and granulocytopenia (which occurs in from 1% to 45% of patients, depending on the clinical stage of disease and the dose of the drug). Didanosine and zalcitibine have both been associated with a severe peripheral neuropathy, which is generally reversible on cessation of the drug. In addition, didanosine has been implicated as a cause of pancreatitis that has been fatal in a small percentage of cases. The toxicities of didanosine and zalcitibine range from 1% to 10%, depending on dose, duration of therapy, and the presence of underlying HIV-related peripheral neuropathy or a previous history of pancreatitis. The clinical hallmark of HIV infection is the development of opportunistic infections and malignancies, which are a consequence of the profound immunodeficiency. The risk of an opportunistic infection increases significantly as the T-helper lymphocyte count declines to less than 20%, or 200 to 250/mm3. The spectrum of opportunistic infections ranges from viruses to protozoa. Patients with advanced HIV disease are also at increased risk of infection with nonopportunistic, community-acquired pathogens. Primary and secondary prophylaxis against the most common AIDS-defining opportunistic infection, Pneumocystis carinii pneumonia, is now recommended. Studies are currently underway to determine the efficacy of prophylaxis against other opportunistic pathogens. Treatment of opportunistic infections associated with AIDS has improved significantly over the past 5 years as new drugs and combination regimens of antimicrobials have been developed.(ABSTRACT TRUNCATED AT 400 WORDS)

Epstein-Barr virus in acquired immune deficiency syndrome (AIDS) and non-AIDS primary central nervous system lymphoma

BACKGROUND

Primary central nervous system lymphoma (PCNSL) still occurs mainly in patients who are immunosuppressed, but its incidence is rising dramatically among immunocompetent individuals. The Epstein-Barr virus (EBV) has been detected by in situ hybridization in PCNSL tumor tissue from patients who are immunodeficient, but not from patients who are immunocompetent. Using the more sensitive polymerase chain reaction (PCR) technique, the authors analyzed PCNSL tissue from 13 patients with acquired immune deficiency syndrome (AIDS) and 13 patients who were immunocompetent for the presence of EBV genome.

METHODS

DNA was extracted from paraffin-embedded biopsy or autopsy specimens. PCR was run using primers for EBV (from the first internal repeat segment of the EBV genome), and identical samples were run simultaneously with primers against actin or the p53 gene as controls to establish the presence of DNA in the sample. Reaction products were also Southern blotted to confirm EBV specificity.

RESULTS

EBV was detected in the tumor tissue of 11 of 13 patients (85%) with AIDS and of 7 of 13 patients (54%) who did not have AIDS. There was a history of illness that might suggest or predispose to immune compromise in 5 of 13 patients without AIDS; however, prior illness did not predict EBV-positive tumors.

CONCLUSIONS

Although mechanisms remain to be clarified, EBV was present in a high percentage of patients with AIDS-related PCNSL and non-AIDS-related PCNSL:

Detection of Epstein-Barr virus in the brain by the polymerase chain reaction

Epstein-Barr virus (EBV) has been implicated in a variety of central nervous system syndromes. In a few well-studied patients, EBV has been detected by viral isolation or EBV DNA has been found by Southern hybridization analysis. Using polymerase chain reaction, we evaluated brain biopsy specimens from 24 patients for the presence of EBV genomes. EBV DNA was found in brain specimens from 18 patients in whom presence of the virus in the brain was suspected clinically or on the basis of serological tests. Six patients had acquired immunodeficiency syndrome; 2 were kidney transplant recipients. Brain specimens from 4 patients with encephalitis due to other herpes group viruses and from a patient with metabolic encephalopathy were negative for EBV DNA as determined by polymerase chain reaction. The findings indicate a need to evaluate the role of EBV in diverse neurological syndromes, especially those occurring in immunodeficient hosts.

Primary cerebral lymphoma: a study of 47 cases probed for Epstein-Barr virus genome

AIMS

To determine the prevalence of Epstein-Barr virus genome in primary cerebral lymphomas occurring in the absence of immune suppression.

METHODS

Forty eight consecutive patients with lymphomas restricted to the central nervous system were identified, all of whom had had neurosurgical biopsies performed at the National Hospitals for Neurology and Neurosurgery, London. Only five patients had some form of underlying immune deficiency; 43 were apparently normal. The tumours were studied with immunohistochemical markers and by in situ hybridisation, using a biotinylated probe to the internal repeat region of Epstein-Barr virus.

RESULTS

All the lymphomas were B cell in origin. Tumours from the five immunosuppressed patients all showed hybridisation, as did two of the "spontaneous" tumours.

CONCLUSIONS

This is the largest series of cerebral lymphomas so far probed for Epstein-Barr virus genome: as more are examined, it is suggested that a small proportion of the tumours from immunocompetent patients will also contain the virus.

Primary central nervous system lymphoma

Primary central nervous system lymphomas (PCNSL) are uncommon neoplasms accounting for less than 2% of brain tumours. Their incidence appears to be increasing across a wide age range, in both immunocompetent and immunosuppressed populations. Particular risk groups include those with congenital and acquired immunodeficiencies and transplant recipients. The spread of the AIDS epidemic has seen large numbers of complicating PCNSL develop. Epstein-Barr virus infection appears to play a role in the development of these lymphomas in the immunosuppressed population. The aetiology of these tumours in the immunocompetent is uncertain. Their tendency to remain within the nervous system is not well understood but may be a function of CNS binding molecules carried by lymphocytes. Clinically PCNSL may present with a wide variety of signs and symptoms and has a capacity to mimic many other neurological conditions. Radiologically they appear as hyperdense homogenous deposits in subcortical white matter. Although most lesions are intermediate or high grade B cell lymphomas, T cell lymphomas are being recognised with increasing frequency. Immunohistochemistry and genotypic analysis have an important role in accurately characterising PCNSL, particularly in stereotactic biopsies. Involvement of multiple areas of the neuraxis, the eye and multiple intracranial sites can occur in the absence of obvious systemic lymphoma. The role of surgery in their treatment is uncertain. A combination of radiotherapy and chemotherapy can increase the length of survival. The prognosis, however, remains poor in comparison with nodal lymphomas, and particularly so in those with AIDS.

Analysis of African Burkitt's and high-grade B cell non-Burkitt's lymphoma for Epstein-Barr virus genomes using in situ hybridization

We investigated the association of Epstein-Barr virus (EBV) with African cases of Burkitt's lymphoma (BL) and high grade B cell non-Burkitt's lymphoma (non-BL) occurring in areas where BL is endemic. The presence of EBV genomes was analysed in 24 cases using in situ hybridization with a 35S-labelled EBV probe applied to paraffin sections. EBV DNA was detected in each of 10 cases of BL in which technically satisfactory results were obtained, the virus being homogeneously distributed in all identifiable tumour cells. Two other cases of BL could not be evaluated because of technical problems. In contrast, EBV DNA was not detected in any case of high-grade non-BL (10 centroblastic and two immunoblastic lymphomas). These results confirm previous reports of the strong association of EBV with endemic BL, but suggest that the virus is not important in the pathogenesis of other types of African high-grade B cell lymphoma from regions where BL is endemic.

Primary central nervous system lymphomas--an update

Primary CNS lymphomas (PCNSL), until recently representing about 1% of all brain tumors, show dramatically increased incidence both in high-risk groups (immunocompromised, AIDS) and in the general population. They are extranodal diffuse non-Hodgkin's lymphomas, the morphology and classification of which are identical to those of systemic lymphomas, although PCNSL show different biological behavior and diagnosis according to the New Working Formulation and updated Kiel classification may be difficult. The majority are large B cell variants of high-grade malignancy; low-grade subtypes and T cell lymphomas are rare. Sixty per cent occur in the supratentorial space (hemispheres, periventricular) and 12% in the posterior fossa; 30% are multiple (50%-70% in AIDS). PCNSL show a male preponderance with a peak incidence in the 5th-7th decade (3rd-4th in AIDS). The duration of diffuse or focal clinical symptoms averages 1-2 months. Computed tomography and magnetic resonance imaging scans show single or multiple or diffuse, often typical lesions. Diagnosis is achieved by evaluation of stereotactic biopsy material or cerebrospinal fluid cytology using immunocytological markers. Current therapy in immunocompetent patients, radiation plus corticosteroids and pre- or postradiation polychemotherapy, shows response rates of 85% with a median survival of 17-44 months, a prognosis similar to that for glioblastoma. Meningeal PCNSL is treated with intrathecal methotrexate or cytosine arabinoside. Transliquoral seeding of PCNSL is frequent, distant metastases occurring in 6%-8%. Therapy of AIDS-related PCNSL makes use of radiation and corticosteroids, and rarely of chemotherapy. The pathogenesis of PCNSL is unknown, but Epstein-Barr virus may be a contributory factor.

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

Primary central nervous system lymphoma occurs more often in patients with AIDS. Epstein-Barr virus (EBV) has been detected in these tumours, but the degree of association has not been defined because of both the highly restricted expression of EBV in malignant tissue and the lack of a technique that is reliable in formalin-fixed paraffin-embedded specimens. EBV-transformed lymphocytes contain short non-protein coding EBV transcripts (EBERs), which are expressed in much higher quantity than other EBV-latency transcripts. We describe a new strategy for detection of latent EBV with these transcripts as targets for in-situ hybridisation. 18 cases of AIDS-related primary CNS lymphoma from a consecutive necropsy series together with specimens from 3 further cases were studied. In each case, a strong positive signal over tumour cells indicated abundant expression of the EBV-EBER1 transcript. This 100% association suggests that the pathogenesis of these AIDS-associated lymphomas may differ from the systemic disease in which only 30-50% of tumours are associated with EBV. A pathogenetic role for EBV was further supported by showing expression of a viral protein (the latent membrane protein) that is implicated as an effector for EBV-associated lymphomagenesis. EBV might have a role as a tumour marker in the diagnosis and management of AIDS-related primary CNS lymphoma.

B-cell lymphoproliferative disorders after bone marrow transplant. An analysis of ten cases with emphasis on Epstein-Barr virus detection by in situ hybridization

Ten patients with B-cell lymphoproliferative disorders (BLPD) after bone marrow transplant were studied in a retrospective analysis of 81 specimens available from biopsy and autopsy material. Histologic review, immunophenotyping, and in situ hybridization (ISH) for Epstein-Barr virus (EBV) sequences were done. Sixty-four specimens showed morphologic evidence of BLPD, demonstrating a heterogeneous spectrum with various degrees of plasmacytoid differentiation. Immunophenotypic evidence of clonality was found in six patients. The ISH detected EBV sequences in all ten patients, including 60 of the 64 specimens with morphologic evidence of BLPD. In addition, ISH identified EBV-infected lymphoid cells in two of 17 sites without morphologic evidence of BLPD. These data demonstrate the utility of ISH for detecting EBV genome in this setting and provide further evidence for the etiologic role of EBV in the pathogenesis of BLPD.

Detection of Epstein-Barr virus genomes in AIDS related lymphomas: sensitivity and specificity of in situ hybridisation compared with Southern blotting

Eighteen cases of AIDS related, non-Hodgkin's lymphomas were examined for the presence of Epstein-Barr virus (EBV) genomes using in situ hybridisation with a 35S-labelled probe. The results were compared with those obtained independently by Southern blot analysis with a 32P-labelled probe of frozen tissue from the same tumours. Technically satisfactory results were obtained with both methods in 15 lymphomas. EBV DNA was detected in seven of 15 (47%) cases by in situ hybridisation and in eight of 15 (53%) cases by Southern blotting (including all the cases positive by in situ hybridisation). The results of EBV DNA detection by the two techniques were identical in 14 of 15 (93%) cases. In situ hybridisation gave no false positive results. This study shows that the sensitivity and specificity of in situ hybridisation for the detection of EBV genomes in AIDS related lymphomas approaches that of Southern blotting, even when using routinely processed archival, paraffin wax embedded material.

Detection of primary Epstein-Barr virus infection in a patient with X-linked lymphoproliferative disease receiving immunoglobulin prophylaxis

Serologic diagnosis for Epstein-Barr virus (EBV) infection is problematic when patients receive exogenous immunoglobulin. We recently diagnosed primary EBV infection by detecting EBV-determined nuclear antigen (EBNA) and EBV-DNA in peripheral blood mononuclear cells (PBMC) using immunofluorescence, in situ hybridization and polymerase chain reaction (PCR) techniques in a patient with X-linked lymphoproliferative disease (XLP) who received prophylactic immunoglobulins for EBV infection. These combined techniques may be helpful for early and accurate diagnosis of EBV infection in highly vulnerable patients.

In situ hybridisation in perspective

In the introduction to this review two questions were posed: is the technology associated with ISH ready for general use, and will the method become an important investigative tool? With the exception of the demonstration of some single and low copy sequences, non-radioactive ISH is now sufficiently developed and simplified to make it a routine technique. It is also clear that ISH will continue to have an important research role. In diagnostic pathology the technique is already providing valuable information and the present decade should see the development of many more diagnostic applications.