Rescue of "crippled" germinal center B cells from apoptosis by Epstein-Barr virus

Epstein-Barr virus (EBV) is associated with B-cell lymphomas such as Hodgkin lymphoma, Burkitt lymphoma, and post-transplantation lymphoma, which originate from clonal germinal center (GC) B cells. During the process of somatic hypermutation, GC B cells can acquire deleterious or nonsense mutations in the heavy and light immunoglobulin genes. Such mutations abrogate the cell surface expression of the B-cell receptor (BCR), which results in the elimination of these nonfunctional B cells by immediate apoptosis. EBV encodes several latent genes, among them latent membrane protein 1 (LMP1) and LMP2A, which are regularly expressed in EBV-positive Hodgkin lymphoma and posttransplantation lymphomas. Since LMP1 and LMP2A mimic the function of 2 key receptors on B cells, CD40 and BCR, respectively, we wanted to learn whether EBV infection can rescue proapoptotic GC B cells with crippling mutations in the heavy chain immunoglobulin locus from apoptosis. We show here that BCR-negative GC B cells readily enter the cell cycle upon infection with EBV in vitro and yield clonal lymphoblastoid cell lines that are incapable of expressing a functional BCR because the rearranged and formerly functional heavy chain immunoglobulin alleles carry deleterious mutations. Our findings imply an important role for EBV in the process of lymphomagenesis in certain cases of Hodgkin lymphoma and posttransplantation lymphomas.     

Expression of the Epstein–Barr virus latent membrane protein 1 induces B cell lymphoma in transgenic mice

The latent membrane protein 1 (LMP1) of the Epstein–Barr virus has transforming properties in rodent fibroblasts and is expressed in most of the cancers associated with Epstein–Barr virus (EBV) infection including posttransplant lymphomas, Hodgkin’s disease, nasopharyngeal carcinoma, and AIDS-related lymphomas. In this study, three lineages of LMP1 transgenic mice were established with LMP1 expressed under the control of the Ig heavy chain promoter and enhancer. Lymphoma developed in all three lineages, and the incidence of lymphoma increased significantly with age with lymphomas developing in 42% of transgenic mice over 18 months. The expression of LMP1 was detected at high levels in the lymphoma tissues but only at trace levels in normal lymphoid tissues. Gene rearrangement of the Ig heavy chain indicated monoclonality or oligoclonality in all lymphomas, some of the lymphoid hyperplastic spleens, and some histologically normal spleens. These data reveal that LMP1, without the expression of other EBV genes, is oncogenic in vivo and indicate that LMP1 is a major contributing factor to the development of EBV-associated lymphomas.     

Epstein-Barr virus infection and associated products (LMP,EBNA2, vIL-10) in nodal non-Hodgkin's lymphoma of human immunodeficiency virus-negative Japanese

Sixty cases of B-cell nodal non-Hodgkin's malignant lymphoma (B-ML), and 46 cases of T-cell nodal lymphoma (T-ML) were surveyed for Epstein-Barr virus (EBV) genomes, RNA, and associated proteins. We used a Southern blot analysis, polymerase chain reaction (PCR), and EBV-encoded small RNA-1 (EBER-1) in situ hybridization to investigate the presence of EBV. We performed an immunohistochemical study on EBV-related oncoproteins, such as EBV-determined nuclear antigen-2 (EBNA-2), latent membrane protein (LMP), and viral interleukin-10 (vIL-10). In addition, we also analyzed the terminal repetitive sequence of EBV (EBV-TR) to investigate the EBV-infected cell clonality. Non-Hodgkin's lymphomas were grouped into three types by number of EBV-infected cells: I) almost all lymphoma cells showed an EBV presence; II) some scattered lymphoma cells showed an EBV presence; and III) only a few cells showed such a presence, which was probably due to a latent EBV infection. In 25 of 60 B-MLs, EBV-infected cells were found; 7 were type I, 1 was type II, and 17 were type III. In 27 of 46 T-MLs, EBV-infected cells were found; no cases were type I, 5 cases were type II, and 22 cases were type III. Seven B-MLs and 3 T cell lymphomas showed clonal TR bands. Expression of EBNA-2 was found in only three B-MLs, whereas LMP was seen in four B-MLs and six T-MLs. All EBNA-2/LMP-positive cases showed an EBV presence. In B-MLs, expression of EBNA-2 and LMP was detected in almost all lymphoma cells; In T-MLs, however, LMP was found in only a small portion of the lymphoma cells. Expression of IL-10 was closely associated with LMP. In summary, it was thus speculated that EBV infection was associated with the various states of lymphomagenesis. © 1996 Wiley-Liss, Inc.     

BCL-2 but not its Epstein-Barr virus-encoded homologue, BHRF1, is commonly expressed in posttransplantation lymphoproliferative disorders [see comments]

Posttransplantation lymphoproliferative disease (PTLD) is virtually always associated with Epstein-Barr virus (EBV) infection. BCL-2 and other proteins that confer resistance to apoptosis have been implicated in the pathogenesis of a variety of malignancies including lymphomas. One EBV protein, BHRF1, is a homologue of BCL-2, whereas another, the latency membrane protein 1 (LMP-1), upregulates BCL-2 expression in vitro. In the present study, we used immunohistochemistry to study the expression of these viral and cellular proteins as well as a variety of other EBV-encoded proteins in PTLD. BHRF1 was not detected in any PTLD specimen, whereas BCL-2 was shown in 12 of 17 lesions examined. With one exception, all LMP1-positive cases also expressed BCL-2 and the absence of LMP1 was always associated with a lack of BCL-2 expression. The results do not support a role for the EBV homologue of BCL-2 in PTLD, but they do support a role for viral induction of BCL-2 expression.     

In situ demonstration of Epstein-Barr virus small RNAs (EBER 1) in acquired immunodeficiency syndrome-related lymphomas: correlation with tumor morphology and primary site

Some acquired immunodeficiency syndrome (AIDS)-related lymphomas (ARLs) are infected with Epstein-Barr virus (EBV), although the frequency and importance of this association is disputed. Using paraffin section RNA in situ hybridization (ISH) with digoxigenin-labeled riboprobes, we screened 16 central nervous system (CNS) non-Hodgkin's lymphomas (NHLs), 101 systemic NHLs, and 11 Hodgkin's disease cases arising in human immunodeficiency virus-seropositive individuals for EBV-encoded small RNA (EBER 1) expression, an EBV gene product transcribed in abundance during latent infection. Tumor cells contained EBV in 85 of 128 ARLs (66%), but infection rates differed with lymphoma type. EBER 1 was expressed in tumor cells in 11 of 11 Hodgkin's disease cases (100%), 15 of 16 CNS NHLs (94%), and 46 of 60 systemic immunoblast- rich/large-cell lymphomas (77%), but in only 12 of 35 Burkitt-type (small noncleaved cell) (34%) and 1 of 6 monomorphic centroblastic (diffuse large noncleaved cell) (17%) lymphomas. In most EBV-positive ARLs, all recognizable viable tumor cells expressed EBER 1. We conclude that (1) EBV infects tumor cells in all AIDS-related Hodgkin's disease cases, in virtually all primary CNS ARLs, and in most systemic immunoblast-rich/large-cell ARLs; (2) only a minority of Burkitt-type and monomorphic centroblastic lymphomas are associated with EBV; and (3) EBER-ISH is ideal for the histopathologic detection of latent EBV in routine tissue specimens.     

Soluble CD23 in cerebrospinal fluid: a marker of AIDS-related non-Hodgkin's lymphoma in the brain.

BACKGROUND: AIDS-related non-Hodgkin's lymphoma (NHL) includes systemic lymphomas, often with brain involvement, and primary central nervous system (CNS) lymphomas. OBJECTIVE: To examine if measurement of soluble CD23 (sCD23) in cerebrospinal fluid (CSF) is useful in the diagnosis and follow-up of AIDS-related NHL. METHOD: sCD23 was measured by enzyme-linked immunosorbent assay and EBV DNA by nested polymerase chain reaction for a group of 134 patients. The NHL group included 14 patients with primary HIV-1 CNS lymphoma, 12 patients with brain involvement of systemic HIV-1 NHL and 10 patients with systemic HIV-1 NHL without brain involvement. These were compared with HIV-1-infected patients with cerebral toxoplasmosis (19), progressive multifocal leukoencephalitis (PML; 8) and AIDS-related dementia (17) and with asymptomatic HIV-1 carriers (54) and uninfected individuals (50). The levels of sCD23 were compared with the presence of Epstein-Barr virus (EBV) DNA in CSF. RESULTS: Significantly higher levels of sCD23 were found in the CSF of the patients with brain lymphoma than in those with systemic NHL (P < 0.002) or with cerebral toxoplasmosis, PML and AIDS-related dementia (P < 0.0001). The sensitivity and specificity of sCD23 in CSF as a marker for detection of brain NHL were 77% and 94%, respectively. High levels of sCD23 were found in CSF from patients with brain NHL independently of the presence (18 out of 26) or absence (8 out of 26) of EBV DNA. CONCLUSIONS: The sCD23 in CSF of HIV-1-infected patients may represent an additional, non-invasive marker for diagnosis of brain involvement in AIDS-related NHL.     

Frequent c-myc oncogene activation and infrequent presence of Epstein- Barr virus genome in AIDS-associated lymphoma

Sixteen cases of histologic intermediate-grade and high-grade AIDS- associated non-Hodgkin's lymphoma (NHL) were studied for the presence and patterns of c-myc gene and bcl-2 locus rearrangements. The presence of Epstein-Barr virus (EBV) sequences and proteins and HTLV-I sequences were also investigated. c-myc gene rearrangements analogous to those observed in sporadic Burkitt lymphomas were detected in 12 of 16 cases. Six of 16 cases had detectable EBV sequences and proteins. None of the cases displayed bcl-2 rearrangements or contained HTLV-I sequences. These data suggest a frequent role for c-myc activation in the pathogenesis of AIDS-associated NHL, independent of histologic type. Conversely, EBV does not appear to be directly involved in lymphomagenesis in the majority of AIDS-associated NHLs.     

Expression profile of MUM1/IRF4, BCL-6, and CD138/syndecan-1 defines novel histogenetic subsets of human immunodeficiency virus-related lymphomas

This study was aimed at defining the histogenesis of the pathologic spectrum of lymphoma arising in the context of human immunodeficiency virus (HIV) infection. Toward this aim, 87 AIDS-related non-Hodgkin lymphomas (AIDS-NHL) and 16 Hodgkin lymphomas arising in HIV+ patients (HIV-HL) were comparatively analyzed for the expression pattern of several B-cell histogenetic markers, including BCL-6 (expressed by centroblasts and centrocytes), MUM1/IRF4 (expressed by late centrocytes and post-germinal center [GC] B cells), and CD138/syn-1 (expressed by post-GC B cells). Expression of MUM1, BCL-6, and syn-1 segregated 3 major phenotypic patterns among AIDS-NHL and HIV-HL: (1) the BCL-6+/MUM1-/syn-1- pattern, selectively clustering with a large fraction of AIDS-Burkitt lymphoma (17 of 19) and of systemic AIDS-diffuse large cell lymphoma (12 of 16); (2) the BCL-6-/MUM1+/syn-1- pattern, associated with a fraction of AIDS-immunoblastic lymphoma (8 of 24); and (3) the BCL-6-/MUM1+/syn-1+ pattern, associated with systemic and primary central nervous system immunoblastic lymphoma (14 of 24) and with primary effusion lymphoma (10 of 10), plasmablastic lymphoma of the oral cavity (7 of 7), and HIV-HL (15 of 16). Analysis of nonneoplastic lymph nodes showed that the 3 phenotypic patterns detected in AIDS-NHL and HIV-HL correspond to distinct stages of physiologic B-cell development-centroblasts (BCL-6+/MUM1-/syn-1-), late GC/early post-GC B cells (BCL-6-/MUM1+/syn-1-), and post-GC B cells (BCL-6-/MUM1+/syn-1+). Expression of the Epstein-Barr virus-encoded latent membrane protein-1 clustered with the BCL-6-/MUM1+/syn-1+ profile throughout the clinicopathologic spectrum of AIDS-NHL and HIV-HL. Overall, these results define novel histogenetic subsets of AIDS-NHL and HIV-HL and may provide novel tools for refining the diagnosis of these disorders.     

Epstein-Barr virus, methotrexate, and lymphoma in patients with rheumatoid arthritis and primary Sjögren's syndrome: case series

OBJECTIVE: Rheumatoid arthritis (RA) and primary Sj?gren's syndrome (SS) are associated with an increased risk of lymphoma. Epstein-Barr virus (EBV), a ubiquitous herpes virus, has been linked etiologically to lymphoma in patients with RA and primary SS. Recently, methotrexate (MTX) has also been linked to the development of these lymphomas. We investigated the frequency of EBV in lymphoma tissue of patients with RA and primary SS and the association of MTX with lymphomagenesis. METHODS: Twenty-three patients with RA and 9 with primary SS with a history of lymphoma were identified by writing to all Arthritis Foundation member rheumatologists in Washington State. Formalin fixed, paraffin embedded tissue blocks were then requested from pathology laboratories. Lymph nodes from 5 RA patients without lymphoma were also studied. In situ hybridization using a biotinylated EBER-1 oligonucleotide probe was used to detect EBV in tissue sections. Positive and negative laboratory controls were used to ensure procedural integrity. RESULTS: Specimens from 21 RA patients were obtained, with 2 subsequently excluded due to specimen quality. Specimens from 6 patients with primary SS were obtained. In situ hybridization for EBV was positive in 5/19 (26%) RA patients and 1/6 patients with primary SS. In the nonmalignant lymph nodes no patient showed EBV. One primary SS and 12 RA patients were known to be taking MTX at the time of lymphoma diagnosis. Of the EBV positive RA lymphoma patients, 4/5 were receiving MTX at the time of diagnosis. These results show that EBV is present in lymphoma tissue of some patients with RA and very few with primary SS. CONCLUSION: EBV is over-represented in the lymphomas of patients with RA, but whether MTX plays a role in predisposing patients with RA and primary SS to the development of lymphoma, perhaps by influencing behavior of EBV, remains unclear.     

A20 (TNFAIP3) genetic alterations in EBV-associated AIDS-related lymphoma

A20, a negative regulator of NF-κB, has been implicated as a tumor suppressor gene in multiple types of B-cell lymphoma. AIDS-related lymphomas (ARLs) are high-grade B-cell lymphomas that are frequently associated with EBV infection. We examined a panel of ARLs for A20 alterations. FISH showed A20 deletion in 6 of 33 cases (18%). A20 mutations were found in 3 of 19 cases (16%), including 2 cases with deletions of the comple-mentary allele. Immunohistochemistry showed the absence of A20 protein in 7 of 55 samples (13%). In contrast to reports in Hodgkin lymphoma in which EBV infection and A20 alteration are mutually exclusive, A20 inactivation was observed in both EBV(+) and EBV(-) cases. The EBV latent membrane protein 1, which activates NF-κB, was not expressed in 12 of 13 cases with A20 loss. In ARLs loss of A20 may be an alternative mechanism of NF-κB activation in the absence of latent membrane protein 1 expression.     

MYC rearrangements in histologically progressed follicular lymphomas.

Histologic transformation of low-grade follicular lymphoma to an aggressive-grade lymphoma occurs in 60% to 80% of patients during their clinical course. The events that drive the transformation process are poorly understood. Deregulation of the MYC gene has been implicated in a small number of cases. This observation led us to examine the molecular organization of the MYC oncogene in 38 cases of histologically transformed lymphomas that arose from follicular lymphomas, and in 18 of the initial pretransformation follicular lymphomas. In addition, we examined 58 "control" low-grade follicular lymphomas that had not yet shown evidence of histologic progression. Immunoglobulin heavy chain and light chain gene rearrangements were detected in all biopsies and rearrangements of the BCL-2 locus were seen in 36 of 38 of the transformed lymphomas (consistent with their origin from follicular lymphomas), in 18 of 18 of the pretransformation follicular lymphomas, and in 51 of 58 of the control follicular lymphomas. All 18 pretransformation follicular lymphoma specimens displayed at least one immunoglobulin gene and BCL-2 rearrangement in common with the corresponding histologically progressed lymphoma, indicating a clonal relationship between the original follicular lymphoma and the histologically transformed lymphoma. MYC rearrangements were detected in 3 of 38 (8%) transformed lymphomas and in 1 of 58 (2%) control follicular lymphomas. The latter MYC rearranged follicular lymphoma was clinically aggressive and transformed to a high-grade lymphoma that led to the death of the patient within 20 months. None of the 18 pretransformation follicular lymphomas showed MYC rearrangement, including two from patients who later demonstrated MYC rearrangement in the progressed aggressive lymphoma. PvuII mutational analysis failed to identify additional MYC gene abnormalities in the progressed lymphomas. Because the Epstein-Barr virus (EBV) is associated with a fraction of high-grade lymphomas and is known to upregulate BCL-2, we looked for a potential role for this agent in our progressed lymphomas. We did not detect viral sequences in any case indicating that EBV does not play a major role in progression. The presence of MYC rearrangements in a small fraction of progressed aggressive lymphomas, and not in the corresponding antecedent follicular lymphomas, suggests that acquisition of a MYC rearrangement is in some cases associated with the transformation event.     

Abdominal presentation of Burkitt's lymphoma in an HIV-positive patient

The incidence of non-Hodgkin's lymphoma (NHL) has greatly increased in the AIDS population. It has been estimated that 8% to 27% of newly diagnosed cases of NHL are related to AIDS. The vast majority are clinically aggressive B cell-derived lymphomas. AIDS-associated NHLs are classified according to their anatomic site of location into three classes: (1) systemic (both nodal as well as extranodal), (2) primary central nervous system, and (3) body cavity-based lymphomas. We present a case report of a patient with HIV infection who presented with abdominal pain and distension and was found to have an intraabdominal type of Burkitt's lymphoma. This case underlines the following points: 1. In the evaluation of acute abdominal disease in a patient with AIDS, both AIDS-related infections as well as malignancies should be sought in the differential diagnosis. 2. Computed tomographic scanning of the abdomen is the modality of choice for characterization of disease as well as direction of appropriate therapy. 3. AIDS-related NHL remains an important biologic model for investigating the development and progression of lymphomas in the immune-deficient host. 4. With the improved survival of patients with AIDS secondary to better prevention and treatment of infections, there may be an increase in AIDS-associated malignancies; therefore, further research pertaining to the development and characterization of therapy modalities of such malignant tumors is mandatory.     

Deletion variants within the NF-kappa B activation domain of the LMP1 oncogene prevail in acquired immunodeficiency syndrome-related large cell lymphomas and human immunodeficiency virus-negative atypical lymphoproliferations

This sequencing study of 17 acquired immunodeficiency syndrome-related lymphomas (9 primary brain, 8 systemic) and 8 human immunodeficiency virus-negative atypical lymphoproliferations expressing large amounts of the latent membrane protein 1 (LMP1) of Epstein-Barr virus was performed to characterize the carboxy terminal NF-kappa B activation domain of LMP1 at the molecular level in an immunocompromised host. In- frame deletions within the NF-kappa B activation domain were identified in all but 2 primary brain lymphomas, 4 systemic lymphomas, and 4 atypical lymphoproliferations, ie, in 60% of cases. In addition, non silent point mutations (range 1 to 5, mean 3.3) were detected in all cases. Although all changes occurred within the first 100 nucleotides of the carboxy terminal NF-kappa B activation domain--a critical sequence for the protein half-life--not a single point mutation was found in the remaining 62 nucleotides, necessary for malignant transformation. Such a clustering of nonrandom sequence variations, associated with a high oncoprotein expression in immunocompromised hosts, suggests that this part of the LMP1 oncogene behaves as a hypervariable region with natural selection of growth-promoting variants through prolongation of the protein half-life.     

Evaluation of cerebrospinal fluid EBV-DNA and IL-10 as markers for in vivo diagnosis of AIDS-related primary central nervous system lymphoma

Summary. Acquired immunodeficiency syndrome (AIDS)-related primary central nervous system lymphoma (PCNSL) is almost always associated with the Epstein-Barr virus (EBV), and EBV-DNA in cerebrospinal fluid (CSF) has been indicated as a useful tumour marker for this HIV-related neoplasm. AIDS lymphomas also show an enhanced production of IL-10 which is generally associated with the presence of EBV in lymphoma cells. We performed a prospective study in 19 HIV seropositive patients with brain mass lesions, and in 21 other AIDS patients with or without other neurological disorders, to assess the in vivo diagnostic value of EBV-DNA and of IL-10 levels in the CSF for primary lymphoma of the central nervous system (CNS). EBV-DNA was detected by a nested polymerase chain reaction (PCR) in the CSF from seven of eight patients with PCNSL, diagnosed by brain biopsy (875% sensitivity) and in none of the 11 controls with brain mass lesions (100% specificity) and of the other 21 AIDS patients with or without neurological disorders. The only patient with PCNSL without detectable EBV-DNA in the CSF was also negative for EBV-DNA in the lymphoma tissue, whereas the samples of the other seven brain lymphomas were all positive for EBV-DNA by nested PCR. Therefore 100% of patients with an EBV-positive primary CNS lymphoma had detectable EBV-DNA in the CSF. No patient from the control group without PCNSL with EBV-negative CSF developed a lymphoma after a mean follow-up of 157 ± 173 d. IL-10 levels in the CSF from the patients with PCNSL were not significantly different from those in the other groups of patients with AIDS. Due to uniformly high levels in the CSF from AIDS patients, IL-10 is not a useful diagnostic marker for AIDS-related brain lymphoma. The detection of EBV-DNA from the CSF by nested PCR is an extremely sensitive and specific diagnostic tool for AIDS-related PCNSL and should be further evaluated as a possible alternative in patients from whom brain biopsy is not advisable.     

Frequent occurrence of B-cell lymphomas in angioimmunoblastic T-cell lymphoma and proliferation of Epstein-Barr virus-infected cells in early cases

Secondary lymphomas occurring in the setting of angioimmunoblastic T-cell lymphoma (AILT) are considered to be rare. Their occurrence has been attributed to Epstein-Barr virus (EBV)-associated lymphoproliferations. A previous study detected a dysregulated hypermutation process in B-cells of AILT. The present study aimed at estimating the frequency of B-cell lymphomas in AILT. By studying the expression of EBV and activation-induced cytidine deaminase (AID) as an indicator of hypermutating cells, we assessed whether B-cell lymphoproliferations in AILT were strictly associated with EBV and whether hypermutation might contribute to lymphomagenesis. Among 161 cases of AILT, diagnosed between 1996 and 2005 at the lymph node registry, Frankfurt, Germany, 19 cases were detected that also had B-cell non-Hodgkin lymphoma (NHL) and two cases had classical Hodgkin lymphoma (HL). EBV was detected in tumour cells of 7/18 NHL and both HL, suggesting that factors other than EBV contribute to lymphomagenesis. AID was expressed in AILT in large cells disseminated in the tissue, implying that the process of somatic hypermutation is ongoing in AILT, although the GC architecture is disrupted. This might be relevant in the development of secondary lymphomas.     

Human immunodeficiency virus-associated malignant lymphoma in eastern Denmark diagnosed from 1990-1996: clinical features, histopathology, and association with Epstein-Barr virus and human herpesvirus-8

The clinicopathological features of human immunodeficiency virus (HIV)-associated lymphoma were investigated in a retrospective study of 85 adult patients in eastern Denmark diagnosed during the period 1990-1996. The possible pathogenetic role of Epstein-Barr virus (EBV) and human herpesvirus 8 (HHV-8) in these tumours was also studied. Seventy patients (82%) presented with extranodal disease and 26 (31%) had CNS involvement at diagnosis. Diffuse large cell B-cell lymphoma was the most frequent histological subtype, comprising 65 of 79 cases available for microscopic re-evaluation (82%) and including 20 of 23 evaluable patients with CNS lymphoma (87%). EBV RNA was demonstrated by in situ hybridization in 51 of 65 evaluable tumours (79%) and in 14 of 16 cases (88%) with CNS-lymphoma. Three cases showed a T-cell phenotype. The presence of HHV-8 DNA was analysed by PCR in 32 cases. A strong band consistent with tumour cell infection was detected in only one case, weaker bands being seen in 4 cases. None of these patients had primary effusion lymphomas. In conclusion, Danish AIDS-related lymphomas are of predominantly high-grade B-cell type with extranodal localization and atypical presentation. Our results provide further evidence that EBV plays a major role in the pathogenesis of large cell AIDS-related lymphoma, whereas HHV-8 does not appear to contribute significantly to the development of solid lymphomas in this group of patients.     

Kaposi's sarcoma-associated herpesvirus DNA sequences in AIDS-related and AIDS-unrelated lymphomatous effusions

Primary effusions presenting as the sole lymphoma localization are also known as body-cavity-based-lymphoma (BCBL), and have been shown to carry Kaposi's sarcoma herpesvirus (KSHV) DNA sequences. The aim of this study was a comparative analysis of the clinical, pathologic and molecular features of BCBL and lymphomatous effusions secondary to tissue-based lymphomas occurring both in the general population and in HIV-1-infected individuals. All the lymphomatous effusion samples (seven AIDS-related and nine AIDS-unrelated) were subjected to an identical multiparameter investigation, including collection of clinical data, analysis of morphology and immunophenotype, as well as the study of viral sequences and genetic lesions. In six cases defined as BCBL (four AIDS-related and two AIDS-unrelated), the patients exhibited exclusive or predominant involvement of the body cavities. BCBL tended to display indeterminate phenotypes (4/6), whereas all AIDS-related and AIDS-unrelated lymphomatous effusions secondary to tissue-based lymphomas consistently expressed B-cell phenotype. Detection of KSHV DNA sequences was restricted to cases of BCBL (3/4 AIDS-related and 1/2 AIDS-unrelated), whereas EBV association (3/4) and expression of EBV-encoded antigens (LMP-1, 2/3; EBNA-2, 1/3) were confined to the AIDS-related BCBL. Overall, our results confirm that both AIDS-related and AIDS-unrelated BCBL preferentially associate with peculiar clinical, immunophenotypic and molecular features among lymphomatous effusions and therefore should be singled out as a specific clinico-pathologic entity.     

Alterations of the p53 tumor suppressor gene in diffuse large cell lymphomas with translocations of the c-MYC and BCL-2 proto-oncogenes

Diffuse large cell lymphomas are aggressive tumors of B-cell origin. In some cases they arise from low-grade follicular lymphomas carrying the t(14;18) translocation, an event that leads to the overexpression of the BCL-2 gene product. More frequently, however, they lack the t(14;18) translocation. Rearrangements of the c-MYC proto-oncogene and mutations of the p53 tumor suppressor gene have also been documented in these lymphomas. This study examines the extent to which alterations in the BCL-2, c-MYC, and p53 genes co-exist within individual lymphomas. Eight diffuse large cell lymphoma cell lines and 11 diffuse large cell lymphoma tumors were assessed for genetic alterations in these three genes. Our results indicate that there is a heterogeneity in the oncogene/suppressor gene profile among diffuse large cell lymphomas. Two cell lines and one tumor carried alterations in all three genes, one cell line carried alterations of c-MYC and p53, and one primary tumor and one cell line carried p53 mutations and the t(14;18). Single alterations of BCL-2 and p53 were also observed. Another cell line had no alterations in any of these genes. The heterogeneity indicates that varied mechanisms may be involved in the generation of diffuse large cell lymphomas.     

Association of Epstein-Barr virus with human immunodeficiency virus-negative peripheral T-cell lymphomas in Japan

The association of Epstein-Barr virus (EBV) with human immunodeficiency virus-negative T-cell lymphoma was examined in 68 patients using the polymerase chain reaction (PCR) with DNA obtained from formalin-fixed paraffin-embedded tissues and an in situ hybridization technique. EBV-encoded RNA (EBER) was detected in 43 of 68 cases (63%) of peripheral T-cell lymphoma: in 100% (11 of 11 cases) of NK/T-cell lymphomas, 70% (14 of 20 cases) of angioimmunoblastic T-cell lymphomas (AILT) and 49% (18 of 37 cases) of other types of peripheral T-cell lymphoma. A positive band was also detected at high incidence (36 of 65 cases; 55%) in a PCR analysis using primers to detect the Bam HI-W fragment of EBV. In the immunohistochemical analysis using a monoclonal antibody to latent membrane protein 1 (LMP-1) of EBV, one of the EBV-encoded latent gene products, LMP-1, was found to be expressed in 13 of 64 cases (20%), but EBNA-2 was not expressed in all the cases examined (0 of 59 cases; 0%). The 5-yr survival rate was 28% for peripheral T-cell lymphomas overall, 0% for NK/T-cell lymphomas, 38% for AILTs and 28% for other types of peripheral T-cell lymphoma. The difference in the overall survival rate between NK/T-cell lymphoma and non-NK/T-cell lymphoma was significant (P = 0.0498 by Log-rank test). Among peripheral T-cell lymphoma patients overall, the group severely infected with EBV (EBER-ISH ++) had a lower 5-yr survival rate (8%) than the group slightly (EBER-ISH +) or not infected (38%; P = 0.0013).