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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Kaposi's sarcoma (KS) is a vascular tumor predominantly found in the immunosuppressed. Epidemiologic studies suggest that an infective agent is the etiologic culprit. Kaposi's sarcoma-associated herpesvirus (KSHV), or human herpesvirus-8 (HHV-8), is a gamma human herpesvirus present in all epidemiologic forms of KS and also in a rare type of a B cell lymphoma, primary effusion lymphoma (PEL). In addition, this virus is present in most biopsies from human immunodeficiency virus (HIV)-associated multicentric Castleman's disease (MCD). MCD is a lymphoproliferative disorder with, like KS, a prominent microvasculature. The genome of KSHV contains the expected open reading frames (ORFs) encoding for enzymes and viral structural proteins found in other herpesviruses, but it also contains an unprecedented number of ORFs pirated during viral evolution from cellular genes. These include proteins that may alter cellular growth (e.g., Bcl-2 and cyclin homologs), induce angiogenesis (e.g., chemokine, chemokine receptor, and cytokine homologs), and regulate antiviral immunity (e.g., CD21 and interferon regulatory factor homologs). No ORF with sequence similarity to the Epstein-Barr nuclear antigens (EBNAs) and latent membrane proteins (LMPs) of Epstein-Barr virus (EBV) is present, but proteins analogous to these in structure and in latent expression are found [e.g., ORF 73 encoding for KSHV latent nuclear antigen (LNA-1) and K12 encoding for a possible latent membrane protein]. Current serologic assays confirm the strong association of infection with KSHV and risk of KS development. The mechanism of how this new virus may trigger the precipitation of KS is still unclear.
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PMID:Kaposi's sarcoma-associated herpesvirus. 970 7

Sixty six patients with non-Hodgkin's lymphomas (NHL) were studied, interleukin-6 (IL-6) was revealed in the blood sera of 33 patients. IL-6 was revealed more frequently in patients with high-grade malignant (p < 0.05) than in those with low-grade malignancy. The largest group of IL-6 positive patients included NHL patients with diffuse large B-cell lymphoma and angioimmunoblastic lymphoma. The marked relationship was found between the serum IL-6 levels and the stage of disease: the serum IL-6 level was significantly lower in untreated patients with Stages II and III disease than in those with end-stage (IV) NHL. IL-6 significantly decreased upon remission, comparable with its level before the initiation of treatment. Analysing the association of prognosis of disease with the serum IL-6 showed that in the group of patients with good (The SNLG index < 2) and intermediate (2 < SNLG index < by 2.6) prognosis, the concentration of this cytokine was significantly lower than in those with poor prognosis (SNLG index > 2.6). There was a significant decrease of the total survival rates of NHL with serum IL-6 found. Therefore, IL-6 is a good prognostic marker in NHL and associated with the activity of a malignant process. Additionally, the increased serum IL-6 levels correlated with NK activities positively and with serum IL-4 levels negatively.
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PMID:[Diagnostic and prognostic value of interleukin-6 in malignant non-Hodgkin's lymphomas]. 984 10

The concept that B-cell lymphomagenesis represents a multistep process is widely accepted. Pathogenetic events should be better defined both in early and late stages of lymphoproliferation. In the past few years, novel study approaches have been focused on understanding the mechanisms of lymphomagenesis. In particular, immune stimulation by infectious agents or autoantigens, T-cell help, altered immunocompetence, and local cytokine networks seem to be crucial in favouring B-cell expansions. In turn, actively proliferating B cells are at higher risk of undergoing genetic alterations that make the clone capable of fully autonomous growth, i.e., fully neoplastic. Peculiar human autoimmune diseases predisposing to B-cell lymphoma represent relevant models to characterize and dissect the temporal sequence of the different lyphomagenetic events. The present review, particularly, focuses on Sjoegren's syndrome, and on recent findings regarding the putative role of hepatitis C virus in B-cell lymphoproliferation. The biologic and clinical implications may be of major relevance for other B-cell disorders characterized by higher prevalence and morbidity.
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PMID:B-cell lymphomagenesis and human autoimmune models. 1035 74

Primary cutaneous lymphomas present in and are confined to the skin with no evidence of extracutaneous disease. The skin is the second most common extranodal site involved by primary lymphoma; 50% are mycosis fungoides (MF)-type cutaneous T-cell lymphoma, with the remainder being peripheral T-cell lymphoma (25%) and B-cell lymphoma (25%). The diagnosis of non-MF primary cutaneous lymphomas differs from that of nodal lymphomas: (1) presentation in the skin more often predicts outcome than histology, (2) immunophenotyping and immunogenotyping studies show differences in chromosomal translocations, cell-surface antigen expression (T-cell receptor [TCR] and immunoglobulin [Ig] heavy and light chains), and oncogene expression, (3) involvement of structural compartments of the skin (epidermis, periadnexal or adventitial dermis, interstitial dermis, and subcutis) aids differential diagnosis in place of nodal architecture, and (4) cytokine and extracellular matrix environments may influence behavior of cutaneous lymphomas. Diagnosis often requires coordinated evaluation of clinical history, immunohistochemistry on paraffin and frozen sections of skin biopsies, and molecular analysis. Classification of primary cutaneous lymphomas by a combined histologic type and clinical behavior is useful.
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PMID:Primary cutaneous lymphomas other than mycosis fungoides. 1037 86

The lymphocyte-predominant (LP) type of Hodgkin's lymphoma (HL) is a unique subtype with characteristic tumor cells (lymphocytic and/or histiocytic [L&H] cells) in associated macronodular structures that resemble progressively transformed germinal centers (PTGCs). Immunohistochemical studies have provided strong evidence that L&H cells are of B-cell lineage and recent molecular studies suggested they are transformed centroblasts. A major clonal population is detectable at presentation, with the immunoglobulin heavy-chain gene often showing evidence of continued somatic hypermutation. In developed nations, Epstein-Barr virus (EBV) is infrequently associated with L&H cells and is probably not involved in the pathogenesis of this disease. L&H cells are frequently surrounded by CD3+, CD4+, CD57+, and CD40L- T cells, but the significance of this T-cell rosetting is unclear. LPHL may be associated with concurrent or subsequent large B-cell lymphoma, and there is evidence of a clonal relationship between the two entities. LPHL may also have nodules or large areas that resemble histiocyte-rich B-cell lymphoma (HRBCL). It is likely that at least some cases of HRBCL arise from LPHL. The same may be true of T-cell-rich B-cell lymphoma. Little is known about cytogenetic abnormalities, the cytokine expression profile, and the expression of several functionally important molecules that have been demonstrated in the Reed-Sternberg (RS) cells of classical HL. The challenge for the future is to obtain a more comprehensive molecular profile of L&H cells and their associated T lymphocytes, so as to provide a framework for eventual elucidation of the pathogenesis of this type of HL.
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PMID:Cellular origin of nodular lymphocyte-predominant Hodgkin's lymphoma: immunophenotypic and molecular studies. 1046 24

A fusion protein containing a B cell lymphoma idiotype (Id) and granulocyte-macrophage colony-stimulating factor (GM-CSF) is a potent stimulator of tumor immunity. In three different tumor models we show that immunization with autologous lymphoma cells that have been engineered to express the Id in the context of GM-CSF is much more effective than immunization with an equivalent dose of the purified protein. The lymphoma Id could be modified by introducing the GM-CSF gene into the immunoglobulin (Ig) heavy chain locus via gene targeting. This approach circumvents the isolation of the rearranged immunoglobulin variable genes from the tumor and the preparation of tumor-specific vector constructs. The low production of Id/GM-CSF fusion proteins by transfected cells, which is a major obstacle in the use of purified fusion proteins for immunotherapy, is due to the presence of the cytokine gene in the immunoglobulin locus. Low production, however, is not limiting in the cell-based setting, because upon in vivo administration of the modified autologous cells, even minute expression levels are sufficient to induce tumor immunity.
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PMID:Induction of tumor immunity by autologous B lymphoma cells expressing a genetically engineered idiotype. 1050 1

Cytokine dysregulation is accepted as one of the pivotal factors in the pathogenesis of B cell lymphomas in HIV-positive patients. So far no data exist on inhibitory cytokines in the regulatory network of HIV-associated B-NHL. Simian immunodeficiency virus (SIV)-infected macaques are a well-established in vivo model of HIV infection in humans. We used this model for the identification of TGF-beta as a growth-inhibitory cytokine of SIV-associated B cell lymphomas. Fifty-seven rhesus macaques were infected with SIVmac. Nine animals developed B cell lymphomas: eight with high-grade lymphomas of the immunoblastic, centroblastic, and "Burkitt-like" type, and one with the centroblastic/centrocytic type according to the Kiel classification. Six of seven analyzed lymphomas were infected with the macaque EBV, herpes virus macaca mulatta (HVMM). The lymphomas and the SIV-associated B cell lymphoma cell line H50 were positive for transcription of the TGF-beta gene. Protein expression and secretion of the active cytokine were proved by immunohistochemistry and ELISA. H50 transcribed the TGF-beta type I and type II receptor (R I/II), betaglycan, and endoglin. Furthermore, all primary lymphoma samples tested were positive for receptor type I/II transcription and protein expression. TGF-beta induced reduction of cell viability by 67% (range, 50-84% and enhanced apoptosis by 69% (range, 33-111%) compared with the control. TGF-beta activity was blocked by a specific anti-TGF-beta antibody. Thus, TGF-beta fulfilled the criteria of a negative autocrine inhibitor in H50. These data identify TGF-beta as a promising candidate as an inhibitory factor in the regulatory network of HIV-associated lymphomagenesis.
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PMID:Transforming growth factor beta is a growth-inhibitory cytokine of B cell lymphoma in SIV-infected macaques. 1055 11

Physiologically, B-lymphocytes are not present in the skin. Even in pathological situations they rarely occur. In contrast, primary cutaneous B-cell lymphomas (CBCL) are characterized by proliferation of B lymphocytes within the skin. This suggests the existence of a certain microenvironment supporting homing and expansion of clonal B cells. Cytokines were demonstrated to be involved in the pathogenesis of cutaneous lymphomas of T-cell origin. Cytokine expression in cutaneous B-cell lymphoma lesions, however, has not been investigated so far. Therefore, the mRNA level of several cytokines was analyzed in biopsies from 7 patients with CBCL and compared to pleomorphic T-cell lymphoma (n = 6), psoriasis (n = 9), and healthy skin (n = 7), using a competitive RT-PCR approach. An overexpression of TNF-alpha, IL-10, and IL-6 was found. Enhanced IL-8 mRNA expression was detected in 2/7 cases. The overexpression of IL-6 and IL-10 in CBCL might be of particular importance, since these cytokines are considered to support B-cell growth. Additionally, the overexpression of IL-10 may contribute to tumor progression since this immunosuppressive cytokine might be involved in downregulation of immunological tumor surveillance, in part by inhibiting type 1 cytokine formation. In fact, we did not detect IFN-gamma and IL-2 expression. Taken together, we found a cytokine pattern in CBCL lesions which might contribute to tumor B-cell growth.
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PMID:Cytokine expression in primary cutaneous germinal center cell lymphomas. 1068 78

We report 2 cases of orbital non-Hodgkin's lymphoma (NHL) with hemophagocytic syndrome (HPS). Patient 1 was a 64-year-old man with a diagnosis of peripheral T-cell lymphoma originating in the right orbita (clinical stage: IV B). Epstein-Barr virus DNA was demonstrated in tissue specimens by polymerase chain reaction. Laboratory findings on admission were WBC: 4,700/microliter, Hb: 12.1 g/dl, Plt: 14.6 x 10(4)/microliter, LDH: 951 IU/l, sIL-2R: 2,553 IU/ml, and ferritin: 5998.1 ng/ml. Patient 2 was a 73-year-old man with a diagnosis of diffuse large B-cell lymphoma originating in the right orbita (Clinical stage: IV B). Laboratory findings on admission were WBC: 9,100/microliter, Hb: 7.7 g/dl, Plt: 15.4 x 10(4)/microliter, LDH: 1,043 IU/l, sIL-2R: 10,090 IU/ml, and ferritin: 2079.3 ng/ml. Both patients had high-grade fever and extremely high serum cytokine levels. Bone marrow aspiration disclosed many histiocytes with hemophagocytosis. In both cases, combined chemotherapy was transiently effective, but patient 1 died of relapse of HPS and patient 2 of cerebral bleeding. Orbital non-Hodgkin's lymphoma with HPS is rare. These cases were interesting in terms of the relationship between HPS and the primary site of lymphoma.
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PMID:[Two cases of orbital non-Hodgkin's lymphoma presenting with hemophagocytic syndrome]. 1069 99

The concept of reverse immune surveillance, first conceived over 12 years ago, described the relationship that existed between germinal center-derived B cell lymphoma cells and the host immune system in SjL/J mice. According to reverse immune surveillance, recognition of tumor cell antigens and a response by the host immune system is required for tumor growth. The phenomenon of reverse immune surveillance related to B cell lymphomas has recently also been characterized in another inbred mouse strain, C57L/J. Moreover, elements of reverse immune surveillance have been observed in several other mouse strains that develop B cell lymphomas, suggesting that this lymphomagenic mechanism may be more common than first envisioned. In SJL and C57L mice, the B lymphoma cells express an MMTV-encoded superantigen (vSAg29) that stimulates syngeneic CD4+ T cells bearing Vbeta16 in their TCR. In contrast to the mRNAs for other MMTVs in normal mouse B cells, vSAg29 mRNA initiates in the env (META) region, undergoes splicing in the 3' env region, and continues through the 3' LTR. Copious cytokine production, including IFN-gamma, IL-4 and IL-5 accompanies the response of the T cells to this vSAg. In addition to cytokines produced by vSAg-responsive T cells, more recent evidence indicates that another cytokine, LTalphabeta2, which is expressed on the lymphoma cell surface, also plays a role in the promotion of the B cell lymphoma growth. It is possible that interaction with LTbeta-R on follicular dendritic cells or other stromal elements facilitates tumor growth by preventing apoptosis of the malignant B cells. To what degree these findings in the mouse are relevant to the development and/or growth of human B lymphoma cells remains to be determined. However, endogenous retroviral sequences do exist in the human genome. Interestingly, some of these sequences are homologous to MMTV, and are transcribed in B lymphoblastoid cells. Moreover microorganisms that are infectious for human B cells, such as EBV and Herpes Virus 8, may also produce superantigens.
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PMID:Requirement for reverse immune surveillance for the growth of germinal center-derived murine lymphomas. 1110 Aug 80


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