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A Gloghini

Publications and source records attributed to A Gloghini.

At least 73 records · Page 4Linked to original sources
PubMed1997

Establishment of HHV-8-positive and HHV-8-negative lymphoma cell lines from primary lymphomatous effusions.

Primary lymphomatous effusions are represented by cases of non-Hodgkin's lymphoma (NHL) which grow in liquid phase in the serous body cavities in the absence of solid tumour masses. Based on morphologic, immunophenotypic, virologic and genotypic features, primary lymphomatous effusions are distinguished into body cavity-based lymphoma (BCBL), Burkitt's lymphoma (BL) and immunoblastic large-cell lymphoma. The histogenesis and pathogenesis of primary lymphomatous effusions are virtually unclarified. In this study, we have established 2 cell lines (CRO-AP/1 and CRO-AP/2) representative of 2 distinct categories of primary lymphomatous effusion, BCBL (CRO-AP/2) and BL (CRO-AP/1). Both CRO-AP/1 and CRO-AP/2 carry monoclonal re-arrangements of the immunoglobulin genes which are identical to those of the respective parental tumours. Consistent with its BCBL origin, CRO-AP/2 is characterised by a non-B, non-T phenotype and harbours infection by HHV-8 (approx. 100 viral copies/cell) and Epstein-Barr virus. Conversely, CRO-AP/1 expresses several B cell-associated antigens, lacks HHV-8 infection and carries the genetic hallmark of BL, i.e., a chromosomal breakpoint of band 8q24. CRO-AP/1 and CRO-AP/2 may be valuable for the biologic characterization of primary lymphomatous effusions, particularly since the number of available cell lines derived from such lymphomatous effusions is extremely limited.

Ascites↗
PubMed1997

BCL-6 protein expression in human peripheral T-cell neoplasms is restricted to CD30+ anaplastic large-cell lymphomas.

The expression pattern of the BCL-6 transcription factor has been assessed in normal and neoplastic B-cell populations and in Hodgkin's disease. However, little is known about BCL-6 expression and its biological significance in T-cell neoplasms. In this study, a series of 59 lymphoma samples, including 27 CD30+ anaplastic large-cell lymphomas (ALCLs), 24 other peripheral T-cell neoplasms, and 8 T-cell lymphoblastic lymphomas (T-LBLs), as well as a panel of t(2;5)-positive lymphoma-derived human cell lines, were evaluated for BCL-6 protein expression by immunohistochemistry on frozen sections and cell smears. To define the relationship between BCL-6 protein and CD30 antigen in CD30+ ALCLs and in non-neoplastic lymph nodes, serial section immunohistochemistry and two-color staining were used in selected CD30+ ALCLs as well as in reactive lymph nodes with non-neoplastic T-cell proliferations. BCL-6 protein was expressed in 12 of 27 (45%) CD30+ ALCL cases, irrespective of their antigenic phenotypes (T-cell or null-cell type), and in the t(2;5)-positive cell lines. In contrast, the remaining 24 peripheral T-cell neoplasms as well as the 8 T-LBLs were considered negative for BCL-6 expression. Coexpression of CD30 and BCL-6, as detected in CD30+ ALCLs, was also found in a subset of non-neoplastic lymphoid elements, namely the large lymphoid cells scattered in the interfollicular areas of reactive lymph nodes. These findings suggest that CD30+ ALCLs may represent the neoplastic transformation of extrafollicular CD30+ cells and that BCL-6 may provide an additional marker for characterizing CD30+ ALCLs.

DNA-Binding Proteins↗
PubMed1997

Characterization of overt B-cell lymphomas in patients with hepatitis C virus infection.

A pathogenetic role of the hepatitis C virus (HCV) has been hypothesized for a subset of B-cell non-Hodgkin's lymphomas (NHLs). However, the preliminary characterization of B-cell NHLs in HCV-infected individuals has been poorly addressed. In the present study, we report detailed information on 35 consecutive patients with overt B-cell NHL of recent onset and HCV infection; all patients referred to a single oncological center in Northeast Italy. Histopathologic evaluation was performed by a single reference hemopathologist, and the link with the two relevant autoimmune diseases predisposing to B-cell NHL and in which HCV has been implied, ie, "essential" mixed cryoglobulinemia (EMC) and Sjogren's syndrome, was investigated. Control groups included 122 consecutive HCV-negative patients with B-cell NHL and 464 consecutive histopathologic cases of B-cell NHL referred to the same center, as well as 127 consecutive patients with HCV infection and without lymphoma referred to a different center in the same geographical area. B-cell NHLs in HCV-infected patients frequently presented at onset (1) an extranodal localization with peculiar target organs of HCV infection (ie, the liver and major salivary glands) being significantly overrepresented; (2) a diffuse large cell histotype without any prior history of low-grade B-cell malignancy or bone marrow involvement; and (3) a weak association with a full-blown predisposing autoimmune disease, although serum autoimmune features were common and cryoglobulins were always present. Therefore, the HCV-related B-cell NHLs in this oncological series presented distinctive features compared with B-cell NHLs in HCV-negative patients, and they differed from bone marrow low-grade NHLs frequently diagnosed in HCV-positive patients with EMC. Such novel information may be relevant for future research aimed at clarifying the possible link between HCV infection, autoimmunity, nonmalignant B-cell lymphoproliferation, and overt B-cell malignancy.

Aged↗
PubMed1997

Frequent mutation of the 5' noncoding region of the BCL-6 gene in acquired immunodeficiency syndrome-related non-Hodgkin's lymphomas.

Acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphomas (AIDS-NHL), a major source of morbidity and mortality among human immunodeficiency virus (HIV)-infected individuals, are derived from B cells and are classified into two major categories, Burkitt's lymphoma (BL) and diffuse large cell lymphoma (DLCL). Anaplastic large cell lymphoma (ALCL) and body-cavity-based lymphoma (BCBL) represent less frequent AIDS-NHL types. The molecular pathogenesis of AIDS-NHL is characterized by distinct genetic pathways, including chromosomal rearrangements of c-MYC and BCL-6 in AIDS-BL and AIDS-DLCL, respectively. In addition to gross rearrangements, recent evidence has suggested that BCL-6 may also be affected by mutations of the gene 5' noncoding regions. Here we have investigated the distribution of BCL-6 mutations in a panel representative of all the AIDS-NHL subtypes. Forty-three AIDS-NHL were analyzed for mutations in the first exon-first intron boundary region of BCL-6. Mutations were detected in all categories of AIDS-NHL (25 of 43 cases; 58%), including 12 of 20 AIDS-BL, 10 of 15 AIDS-DLCL, two of three AIDS-ALCL, and one of five of AIDS-BCBL. BCL-6 mutations occurred independent of BCL-6 rearrangements and presence of other genetic lesions frequently associated with AIDS-NHL. These results indicate that mutations of BCL-65' noncoding regions represent the most common genetic alteration presently detectable in AIDS-NHL. The frequency of these mutations, as well as their location in the proximity of BCL-6 regulatory sequences, suggest that they may play a role in AIDS-related lymphomagenesis.

Biomarkers, Tumor↗
PubMed1997

Reed-Sternberg cells of classical Hodgkin's disease react with the plasma cell-specific monoclonal antibody B-B4 and express human syndecan-1.

Although the cellular origin of Reed-Sternberg (RS) cells of classical Hodgkin's disease (HD) has been a controversial issue for many years, recent immunophenotypic and molecular studies have suggested that RS cells of a subset of classical HD cases may be related to B cells. To further define the immunophenotypic features and the differentiation stage of RS cells, a series of 56 HD samples, including both nodular lymphocyte predominance (LP) (eight cases) and classical HD (nodular sclerosis [NS], 32 cases; mixed cellularity [MC], 16 cases) with a non-T-cell phenotype, were evaluated for the immunohistochemical expression of the B-B4 antigen, a specific marker for terminally differentiated B cells. Because the cDNA of the B-B4 antigen encodes syndecan-1, a member of a family of transmembrane heparan sulfate proteoglycans thought to be involved in binding cells of the B lineage to the interstitial matrix, the B-B4 immunoreactivity was correlated with the expression of syndecan-1 in HD-derived cell lines (L428, KM-H2), as detected by both reverse transcriptase polymerase chain reaction (RT-PCR) studies and Western blotting. Our results show that B-B4 reacts with RS cells and their morphological variants of all cases of classical HD, irrespective of their antigenic phenotype (B, undetermined), albeit at a varying degree of cellular expression. Notably, a high reactivity and staining intensity for the B-B4 monoclonal antibody (MoAb) was restricted to tumor cells from NS HD. In cases of the latter subtype, B-B4 positivity was also found in sclerosis-trapped spindle cells (fibrocytes/fibroblasts). Conversely, the putative tumor cells of nodular LP HD were consistently unreactive with the B-B4 MoAb. Finally, we have demonstrated by RT-PCR, flow cytometry, and Western blotting that cultured RS cells, of B and undetermined phenotype, express syndecan-1 mRNA and produce a form of syndecan-1, recognized by the B-B4 MoAb, which is predominantly associated with glycosaminoglycans and is present at the cell surface. Our detection of the plasma cell-specific antigen B-B4 (syndecan-1) on tumor cells of classical HD further supports that RS cell progenitors may be related to germinal/postgerminal center mature B cells and suggests that expression of syndecan-1 may contribute to some of the typical biologic and histopathologic features of classical HD, with a special regard to the NS subtype.

Antibodies, Monoclonal↗
PubMed1997

Human non-Hodgkin's lymphomas overexpress a wild-type form of p53 which is a functional transcriptional activator of the cyclin-dependent kinase inhibitor p21.

A large fraction of non-Hodgkin's lymphomas (NHLs) accumulate a wild-type form of the p53 tumor suppressor protein at the nuclear level. In normal cells, p53 induction is associated with a temporary cell growth arrest at the G1-S boundary of the cell cycle. This activity of p53 as a G1 checkpoint molecule is strictly dependent on its ability to induce the transcription of the inhibitor of the cyclin dependent kinase, p21. To verify the functionality of the wild-type p53 protein accumulated in NHL cells, 70 cases were comparatively analyzed for p53 and p21 expression and status of the respective genes. Overexpression of the wt p53 protein was associated with the accumulation of p21, indicating that p53 is functional with respect to p21 induction in these tumors. The coaccumulation of p53 with Ki-67 antigen indicates that wt p53-positive cells and p21-positive cells, as well, are actively proliferative elements, supporting the notion that p53-induced, p21-mediated growth arrest is somehow overridden in NHL cells. No p21 mutation or particular allele variant was shown to correlate with p21 protein accumulation, thus excluding a role for p21 structural abnormalities. Taken together, our data suggest the existence in NHL of a peculiar mechanism of functional inactivation of the p53 G1 checkpoint pathway occurring downstream of the CDK inhibitor p21.

Cell Division↗
PubMed1997

CD30 ligand is frequently expressed in human hematopoietic malignancies of myeloid and lymphoid origin.

CD30 ligand (CD30L) is a type-II membrane glycoprotein capable of transducing signals leading to either cell death or proliferation through its specific counterstructure CD30. Although several lines of evidence indicate that CD30L plays a key role as a paracrine- or autocrine-acting surface molecule in the deregulated cytokine cascade of Hodgkin's disease, little is known regarding its distribution and biologic significance in other human hematopoietic malignancies. By analyzing tumor cells from 181 patients with RNA studies and immunostaining by the anti-CD30L monoclonal antibody M80, we were able to show that human hematopoietic malignancies of different lineage and maturation stage display a frequent and broad expression of the ligand. CD30L mRNA and surface protein were detected in 60% of acute myeloid leukemias (AMLs), 54% of B-lineage acute lymphoblastic leukemias (ALLs), and in a consistent fraction (68%) of B-cell lymphoproliferative disorders. In this latter group, hairy cell leukemia and high-grade B-cell non-Hodgkin's lymphoma (B-NHL) expressed a higher surface density of CD30L as compared with B-cell chronic lymphocytic leukemia and low-grade B-NHL. Purified plasmacells from a fraction of multiple myeloma patients also displayed CD30L mRNA and protein. A more restricted expression of CD30L was found in T-cell tumors that was mainly confined to neoplasms with an activated peripheral T-cell phenotype, such as T-cell prolymphocytic leukemia, peripheral T-NHL, and adult T-cell leukemia/lymphoma. In contrast, none of the T-lineage ALLs analyzed expressed the ligand. In AML, a high cellular density of CD30L was detected in French-American-British M3, M4, and M5 phenotypes, which are directly associated with the presence on tumor cells of certain surface structures, including the p55 interleukin-2 receptor alpha-chain, the alpha(M) (CD11b) chain of beta2 integrins, and the intercellular adhesion molecule-1 (CD54). Analysis of normal hematopoietic cells evidenced that, in addition to circulating and tonsil B cells, a fraction of bone marrow myeloid precursors, erythroblasts, and subsets of megakaryocytes also express CD30L. Finally, we have shown that native CD30L expressed on primary leukemic cells is functionally active by triggering both mitogenic and antiproliferative signals on CD30+ target cells. As opposed to CD30L, only 10 of 181 primary tumors expressed CD30 mRNA or protein, rendering therefore unlikely a CD30-CD30L autocrine loop in human hematopoietic neoplasms. Taken together, our data indicate that CD30L is widely expressed from early to late stages of human hematopoiesis and suggest a regulatory role for this molecule in the interactions of normal and malignant hematopoietic cells with CD30+ immune effectors and/or microenvironmental accessory cells.

Acute Disease↗
PubMed1997

Epstein-Barr virus strains with latent membrane protein-1 deletions: prevalence in the Italian population and high association with human immunodeficiency virus-related Hodgkin's disease.

Six Epstein-Barr virus (EBV)-related lymphoproliferative disorders were investigated to verify whether the EBV strain harbored by neoplastic cells had the same EBNA-2 and latent membrane protein-1 (LMP-1) DNA sequences of the virus carried by normal lymphocytes of the same patients. Within each case, the analysis of neoplastic lymph nodes, reactive lymphadenopathies, and/or EBV+ spontaneous lymphoblastoid cell lines gave concordant results with respect to type-specific EBNA-2 region and LMP-1 gene. In particular, five cases showed the same deletion in the 3' end of the LMP-1 gene in both normal and neoplastic cells. We also determined the prevalence of LMP-1 deletions in a large series of normal peripheral blood mononucleated cells (PBMCs) from Italian individuals. The analysis showed that 50% (9 of 18) of PBMCs from human immunodeficiency virus (HIV)-seronegative donors carried a 30-bp deletion in the C-terminal portion of the LMP-1 gene, whereas a nondeleted fragment was amplified in about 44% (8 of 18) of the cases. Only one sample (5.6%) showed the amplification of a full-length LMP-1 band together with a deleted fragment. Similarly, PBMCs from HIV-infected patients showed an almost equivalent prevalence of full-length (17 of 37, 46%) and deleted (16 of 37, 43.2%) LMP-1 fragments, whereas about 11% of samples (4 of 37) showed evidence of double infections. Of note, deletions in the LMP-1 gene were detected with similar prevalence values in EBV+ Hodgkin's disease (HD) (13 of 30, 43.3%) and non-Hodgkin's lymphoma (NHL) (2 of 5, 40%) cases from HIV-seronegative patients and in HIV-related, EBV+ NHLs (4 of 7, 57.1%). Conversely, a 30-bp LMP-1 deletion was found in 10 of 12 HIV-associated HD cases (83%), a prevalence significantly higher than that detected in HIV-unrelated HD (P = .01). These findings indicate that: (1) the same EBV strain carrying LMP-1 deletions is harbored by normal and neoplastic cells of patients with EBV+ disorders, ruling out that these mutations might result from immunoselection phenomena; (2) in the Italian population, the prevalence of LMP-1 deletion mutants is comparable to that of EBV strains with full-length LMP-1; (3) HIV-induced immunosuppression is not associated with an increased prevalence of LMP-1 deletions in PBMCs; and (4) HIV-related HD cases, but not those of HIV-seronegative Italian patients, are closely correlated with the presence of LMP-1 deletions, suggesting that infection with these strains may increase the risk of developing HD in the HIV setting.

Gene Deletion↗
PubMed1997

High CD40 membrane expression in AIDS-related lymphoma B cell lines is associated with the CD45RA+, CD45RO+, CD95+ phenotype and high levels of its soluble form in culture supernatants.

CD40 is a membrane glycoprotein expressed on normal and neoplastic B lymphocytes. Stimulation through CD40 regulates important cellular functions, but the effects depend on its membrane density. While extensive studies have characterized CD40 in non-Hodgkin lymphomas of immunocompetent individuals, little is known on the characteristics of this molecule in lymphomas arising in immunocompromised hosts. The aim of this study was to characterize the pattern of CD40 expression in an in vitro model constituted by AIDS small non-cleaved lymphoma (SNCCL) cell lines. The analysis of CD45 isoforms, a group of molecules alternatively spliced during B cell differentiation, has been chosen to correlate this process to the number of CD40 molecules per cell in these cell lines. Since Apo 1/Fas expression is upregulated on B lymphocytes after CD40 ligation and this expression is functionally relevant, we wanted to know whether a different CD40 pattern in AIDS-SNCCL cell lines could influence CD95 expression. We have shown that 3 of these cell lines (PA 682, Es III, and HBL-2) have high membrane CD40 expression (> 100,000 molecules/cell); they release large amounts of soluble CD40 (sCD40) in culture supernatants (>500 pg/ml), are CD45RA/RO double labelled, and express the Apo 1/Fas (CD95) antigen. On the contrary, low CD40 membrane antigen cell lines (BRGIgA, HBL-2, NC 71, AS 283A, and LAM C3+, < 50,000 molecules/cell) release low amounts of sCD40 (<300 pg/ml), are CD45RA+ but CD45RO-, and do not express CD95. EBV has no role in CD40 and CD45 isoform behaviour, because EBV superinfection of the EBV negative, low membrane CD40 HBL-2 cell line does not modify CD40 membrane expression, sCD40 production, or CD45 isoform and CD95 expression. Our data suggest that membrane CD40 in AIDS-SNCCL cell lines might be a key element in the regulation of their pathophysiology by influencing the expression of CD45 isoforms and of CD95, and by the release of its soluble form.

Antigens, CD↗
PubMed1997

Detection of BCL-6 rearrangements and p53 mutations in Malt-lymphomas.

Twenty-seven lymphomas of mucosa-associated lymphoid tissue (MALT) derived from distinct anatomical sites were tested for the presence of genetic lesions commonly involved in B-cell lymphomagenesis, including activation of proto-oncogenes (BCL-1, BCL-2, BCL-6, and c-MYC), disruption of tumor suppressor loci (p53, 6q), and infection by viruses [Epstein-Barr virus (EBV), and Kaposi's sarcoma-herpesvirus/human herpesvirus-8 (KSHV/HHV-8)]. Sixteen low-grade and 11 high-grade MALT-lymphomas were included in the study. The presence of genetic lesions was tested by a combination of molecular approaches, including Southern blot hybridization, polymerase chain reaction (PCR), and PCR-single strand conformation polymorphism followed by DNA direct sequencing. Alterations of BCL-1, BCL-2, or c-MYC, as well as infection by KSHV/HHV-8, scored negative in all MALT-lymphomas analysed. Conversely, rearrangements of BCL-6 and mutations of p53 clustered with a fraction of high-grade MALT-lymphomas. Deletions of 6q occurred in selected cases of both low- and high-grade MALT-lymphomas, whereas a monoclonal infection by EBV was restricted to one single patient. These data corroborate the notion that the molecular pathogenesis of MALT-lymphomas differs substantially from that of nodal B-cell lymphomas. Occasionally, however, a proportion of high-grade MALT-lymphomas may harbor selected genetic lesions among the ones commonly involved in nodal B-cell lymphomagenesis.

Blotting, Southern↗
PubMed1997

Characterization of prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome.

OBJECTIVE: To determine whether the prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome (SS) may be better characterized by the integration of clinical, pathologic, and molecular data, the latter focusing on the expansion, persistence, and dissemination of clonal B cells in the course of the disease. METHODS: Multiple tissue lesions (synchronous from different tissues and metachronous from the same tissue) were evaluated in biopsy specimens obtained from 6 consecutive patients with SS who had an associated lymphoproliferative disorder. Fully benign gastric lesions were evaluated in tissue from an additional 11 patients with SS who had no associated lymphoproliferative disorder. Multiple and complementary molecular analyses of B cell clonality were used: Southern blot, polymerase chain reaction, single-strand conformation polymorphism, DNA sequencing, and hybridization with clonospecific oligoprobes. All the patients were then strictly followed up for the appearance of lymphoma. RESULTS: Different scenarios of SS-associated B cell lymphoproliferation were identified: 1) the ongoing expansion of the same dominant clone, localized or disseminated, in tissue from 2 patients, 1 of whom later developed an overt B cell lymphoma; 2) different dominant clones in different synchronous or metachronous tissues from the remaining 4 patients with an associated lymphoproliferative disorder; and 3) small oligoclonal expansions in 7 of the 11 benign gastric lymphoid infiltrates. CONCLUSION: Prelymphomatous B cell lymphoproliferation in SS was better characterized following integration of the findings. The different types of B cell clonal expansion (oligoclonal or monoclonal, smaller or larger in size, fluctuating or established, localized or disseminated) may imply a different risk of lymphoma progression. An accurate clinical, histopathologic, and molecular characterization may therefore be crucial in future studies aimed at clarifying the pathobiology of SS-associated lymphoproliferation.

Adult↗
PubMed1997

Pathological and immunophenotypic features of adult non-Hodgkin's lymphomas by age group.

To elucidate age-related differences in non-Hodgkin's lymphoma (NHL), the authors evaluated 950 consecutive, human immunodeficiency virus-negative patients (age range, 15 to 96 years) observed between July 1988 and June 1995 in the same Italian cancer institute. Patients were grouped into six age groups and cross-tabulated by Working Formulation (WF) categories and other newly recognized entities according to the Revised European American Lymphoma (REAL) classification, cell immunophenotype, and nodal or extranodal location. There was a tendency of the low-grade category to increase with increasing age (16.8% in the age group 15 to 34 years to 32.4% in the age group 65 to 74 years), although a subsequent decline was seen at age 75 years or older (23.2%). Also the intermediate-grade category was more frequent in the elderly (46.6% and 49.4% at 65 to 74 years and at 75 years or older, respectively). High-grade category showed compared with low and intermediate grade ones, a significant downward trend with age (X2 for trend = 25.31; P < .001), interrupted in only the oldest age group. The relative excess of low-grade NHL in patients older than 55 years. of age was accounted for by the high proportion of small lymphocytic lymphomas, which, however, somewhat declined at age 75 years or older. Conversely, the relative excess of high-grade NHL below age 35 years chiefly derived from the high percentage (28.4%) of CD30-positive anaplastic large cell lymphomas. B- and T-cell lymphomas accounted for 85.9% and 9.0% of all cases, respectively. B- and T- and non-B, non-T-cell and histiocytic NHL accounted for the remaining 5.1%. A highly significant trend of increase in the proportion of B-cell lymphomas with age increase was noted (X2 for trend = 21.90; P < .001); chiefly attributable to the excess of T-cell (15.1%) and undetermined phenotype (18.6%) in patients younger than 35 years of age. Extranodal location was not significantly related to age groups. Thus, the present study showed some interesting differences in NHL morphology and cell phenotype according to age, avoiding, at the same time, the arbitrariness of patients' dichotomization into elderly and nonelderly.

Adolescent↗
PubMed1997

Microsatellite instability in KSHV/HHV-8 positive body-cavity-based lymphoma.

Body-cavity-based lymphoma (BCBL) is a rare non-Hodgkin-'s lymphoma (NHL) type growing in liquid phase in the body cavities. Virtually all BCBL associate with Kaposi's sarcoma-associated herpesvirus/human herpesvirus type-8 infection in the absence of molecular alterations typical of other NHL categories. Microsatellite instability (MSI), a specific variant of genomic instability frequently associated with human cancers, has not been tested in BCBL thus far. In this report, we have analyzed the presence of MSI in the tumor cells of a male patient affected by AIDS-related BCBL. The genomic configuration of 12 distinct microsatellite loci was investigated by polymerase chain reaction amplification of DNA obtained from the patient's tumor cells and from autologous peripheral blood mononuclear cells. MSI was observed at 4/12 microsatellite repeats tested. Absence of the germline allele at one microsatellite locus mapping to chromosome X indicates that, in this BCBL case, MSI represents a clonal genetic lesion affecting virtually all tumor cells. These data suggest that MSI may be potentially involved in the pathogenesis of AIDS-related BCBL.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Genetic heterogeneity of AIDS-related small non-cleaved cell lymphoma.

AIDS-related small noncleaved cell lymphoma (AIDS-SNCCL) includes Burkitt's lymphoma (BL) and high-grade B-cell Burkitt-like lymphoma (BLL). Due to the marked polymorphism of AIDS-related non-Hodgkin's lymphomas (AIDS-NHL), the morphologic distinction between these two types of lymphomas is frequently controversial, although it may bear clinical relevance. Although the molecular features of AIDS-BL have been clarified to a certain extent, the genetic peculiarities of AIDS-BLL have not been investigated in detail. In this study we have compared morphologic and genetic features of AIDS-BL and AIDS-BLL in a blind coded fashion. Molecular studies were focused on the genetic lesions known to be implicated in AIDS-NHL, including alterations of c-MYC, BCL-6, p53, deletions of 6q, as well as infection by EBV and HHV-8. Alterations of c-MYC occurred in 10/10 AIDS-BL, whereas they were restricted to 2/10 AIDS-BLL (P < 0.01). Mutations of p53 were present in 5/10 AIDS-BL, whereas they were consistently absent among AIDS-BLL (n = 10; P < 0.05). Infection by EBV occurred in 30% of both AIDS-BL and AIDS-BLL. Rearrangements of BCL-6, deletions of 6q and infection by HHV-8 scored consistently negative in both AIDS-BL and AIDS-BLL. Based on the genetic lesions tested, the molecular profile of AIDS-BLL appears to be closer to that of AIDS-related diffuse large cell lymphoma (AIDS-DLCL) than to that of AIDS-BL. In contrast to AIDS-BLL however, AIDS-DLCL carried rearrangements of BCL-6 in a fraction of cases (2/9). This study, the largest of its kind reported so far, suggests that AIDS-BL and AIDS-BLL have a different molecular pathogenesis and that characterization of genetic lesions may help to distinguish between these two lymphomas.

Blotting, Southern↗
PubMed1997

Point mutations of the BCL-6 gene in Burkitt's lymphoma.

BCL-6 codes for a transcription factor implicated in chromosomal translocations of diffuse large cell lymphomas. Recent evidence indicates that BCL-6 may also be altered by mutations of its 5' non-coding regions. In this study we have investigated the distribution of BCL-6 5' mutations among 35 Burkitt's lymphoma cases representative of the epidemiologic variants of the disease. Mutations were detected in 6/21 (28.6%) sporadic Burkitt's lymphomas and 7/14 (50%) endemic Burkitt's lymphomas. These data expand the spectrum of B-cell non-Hodgkin's lymphomas associated with BCL-6 5' mutations and have implications for the pathogenesis, histogenesis and clinical monitoring of Burkitt's lymphoma.

Burkitt Lymphoma↗
PubMed1997

Analysis of human herpesvirus type 8 infection in AIDS-related and AIDS-unrelated primary central nervous system lymphoma.

Human herpesvirus type 8 (HHV-8) has been proposed as a pathogenetic factor for immunosuppression-associated primary central nervous system lymphoma (PCNSL). To verify this hypothesis, HHV-8 infection was investigated in 31 persons with PCNSL (16 AIDS-related, 15 AIDS-unrelated) and in 30 persons with systemic B cell non-Hodgkin's lymphomas (B-NHL; 15 AIDS-related, 15 AIDS-unrelated). All subjects with PCNSL scored negative by single-step polymerase chain reaction (PCR), suggesting a tumor virus load of <100 viral copies/200,000 human haploid genome equivalents (HHGE). By applying Poisson assumptions to nested PCR, 16 of 31 persons with PCNSL were devoid of HHV-8 sequences: 1 subject with AIDS and PCNSL had 1-100 viral copies/200,000 HHGE, and 14 with PCNSL had <1 viral copy/200,000 HHGE. Similarly, 10 of 30 persons with systemic B-NHL were devoid of HHV-8 sequences; 20 had <1 viral copy/200,000 HHGE. The extremely low levels of infection rule out a role of HHV-8 in PCNSL pathogenesis and are consistent with HHV-8 infection of bystander cells contaminating the tumor clone.

AIDS-Related Opportunistic Infections↗
PubMed1997

HIV-associated human herpesvirus 8-positive primary lymphomatous effusions: radiologic findings in six patients.

PURPOSE: To define the imaging features of body cavity-based lymphoma (BCBL) related to the acquired immunodeficiency syndrome. This is a peculiar type of non-Hodgkin lymphoma harboring infection by human herpesvirus 8 (HHV-8) and displaying a peculiar tropism for the serous body cavities. MATERIALS AND METHODS: At diagnosis of BCBL, six consecutive patients were investigated with radiography of the chest and conventional computed tomography (CT) of the chest and abdomen. For all patients, clinical features and results of biologic characterization of the lymphoma were also available. RESULTS: In all patients, chest radiographs displayed bilateral or unilateral pleural effusion in the absence of parenchymal opacities or mediastinal enlargement. CT scans confirmed chest radiographic findings and revealed a slight thickening of the parietal pleura in all patients and a pericardial thickening in four patients. CT also depicted pericardial and abdominal effusions in five and two patients, respectively, in the absence of solid tumor masses or parenchymal abnormalities. CONCLUSION: BCBL must be included among the differential diagnoses of serous effusions detected radiologically in individuals infected with the human immunodeficiency virus (HIV). Since the combination of serous effusion, slight serosal thickening, and absence of solid masses is compatible with, though not specific for, BCBL in the context of HIV infection, radiologic findings need to be complemented by a detailed biologic and virologic characterization of tumor cells.

Adult↗