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

Bcl-x and c-Myc have an important role for the immune response by regulating the programmed cell death (apoptosis) of lymphocytes. Dysfunction of these selection processes can lead to the development of malignant lymphoma. The present study aimed at defining the differential expression of apoptosis, Bcl-x and c-Myc in normal and in malignant lymphoid tissues. Follicular centre lymphoma (FCL-F) and mantle cell lymphoma (MCL) contained the lowest apoptotic indices (AIs), whereas Burkitt's lymphoma (BL) had the highest AIs. The AIs correlated significantly with the growth rates of the tumours and with the extent of Bcl-x expression. Bcl-x was expressed in almost all BL cells, but in few tumour cells in FCL-F and in MCL. c-Myc, in contrast, was found in the majority of the tumour cells in FCL-F and in MCL, but not in BL. Whereas the extent of Bcl-x expression correlated positively with the growth rates, an inverse correlation was observed between the percentages of c-Myc-positive tumour cells and the growth rates of the tumours. We conclude that normal and malignant lymphoid tissues have a distinct pattern of apoptosis and that expression of Bcl-x and c-Myc in B cell lymphoma is differentially regulated.
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PMID:Differential expression of apoptosis, Bcl-x and c-Myc in normal and malignant lymphoid tissues. 926 May 77

A 77-year-old man was admitted because of massive pericardial effusion and cardiac tumor. Cytological examination of the effusion and histological examination of a subcutaneous tumor in the chest wall revealed diffuse large B cell lymphoma. The immunophenotype of tumor cells was CD5+ CD20+ CD22+ CD38+ HLA-DR+ CD19-. Chromosome analysis revealed complex abnormal karyotypes containing t(8;14) (q24;q32). C-myc gene rearrangement was shown by Southern blotting. Chemotherapy with pirarubicin, cyclophosphamide, vincristin, and prednisolone (THP-COP) was not effective for his lymphoma. He suffered from cardiac tamponade and died at 5 months after diagnosis. Autopsy revealed a large cardiac tumor, extensive epicardial infiltration, tiny tumors in the lung and pancreas, but no lymphadenopathy, the combination of which suggested a primary cardiac lymphoma. Immunohistochemistry for p53 protein showed nuclear staining of more than 50% of the lymphoma cells. In situ hybridization for EBER-1 was negative. Rearrangement of c-myc gene and overexpression of p53 protein are usually observed in Burkitt's lymphoma and some cases of high grade lymphomas including AIDS-associated non-Hodgkin lymphomas. In this case the association of these molecular findings and resistance to chemotherapy is suggested.
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PMID:[Diffuse large B-cell lymphoma mainly involving the heart and showing t(8;14) (q24;q32) with c-myc rearrangement]. 936 67

We have generated cytotoxic T-lymphocytes (CTLs) from the peripheral blood (PB) of eight B-cell non-Hodgkin's lymphoma (NHL) patients by in vitro coculture with autologous fresh tumor cells. Their functional activity was assessed in 51Cr release assay and was found to be MHC class I restricted. Our results indicate the presence of T-cells cytotoxic for autologous tumor cells in the PB of these patients but these were relatively small numbers in small lymphocytic lymphomas (SLLs). Treatment of fresh tumor cells with rIFN-gamma and rTNF-alpha alone, or in combination significantly increased their susceptibility in 4/5 cases of SLLs, and a case of diffuse large cell lymphoma and Burkitt lymphoma (BL), while, B-cell lymphoma, rich in T-cells, did not show any appreciable increase. Fresh tumor cells were also analysed for MHC class I and ICAM-1 antigens by flow cytometry, in 5/8 cases before and after cytokine treatment. Significant upregulation of MHC class I antigens but with no detectable change in ICAM-1 observed in a case of SLL and BL, correlated with enhanced susceptibility. These findings suggest the possible role of MHC class I antigens in the cytotoxic susceptibility of autologous tumor cells in B-cell NHL.
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PMID:Auto-tumor reactive cytotoxic T-cell responses in B-cell non-Hodgkin's lymphoma. 937 6

Lym-2 is a murine monoclonal antibody (MoAb) directed towards a human class II molecule variant reactive with both normal and neoplastic human B lymphocytes. Previous studies have shown that signals transmitted by class II molecules that stimulate normal lymphocytes can be inhibitory for B-cell lymphoma growth by signaling activation-induced cell death. Therefore, we sought to evaluate the effects of nonconjugated murine Lym-2 and a human-mouse chimeric Lym-2 (chCLL-1; with murine variable regions and human constant regions) MoAb on the growth of various human lymphomas by using both in vitro and in vivo assays. Cell lines derived from Burkitt's lymphomas, diffuse large cell B-cell lymphomas, anaplastic large-cell lymphomas, and Epstein-Barr virus-induced B-cell lymphomas were incubated with Lym-2 or chCLL-1 in vitro, and effects on proliferation were determined by [3H]-thymidine incorporation. The effects of Lym-2 in vitro were also compared with those of Lym-1, which is a similar MoAb that has been evaluated clinically. After immobilization, which enhances crosslinking of the MoAbs, both Lym-2 and chCLL-1 were capable of directly inhibiting the growth of various lymphoma lines in vitro. These human lymphomas were then transferred into mice with severe combined immunodeficiency to evaluate the efficacy of these MoAbs in vivo. Treatment with either murine Lym-2 or the chimeric chCLL-1 were significantly effective in improving the survival of tumor-bearing mice. These results indicate that stimulation by nonconjugated chCLL-1 may offer a biological approach to the treatment of various human lymphomas.
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PMID:Antitumor effects of nonconjugated murine Lym-2 and human-mouse chimeric CLL-1 monoclonal antibodies against various human lymphoma cell lines in vitro and in vivo. 937 98

Post-transplant lymphoproliferative disease (PTLD) is a major cause of death and disease in transplant patients. We describe 4 cases with histologically confirmed malignant lymphoma arising in the Birmingham liver transplant programme between 1982 and 1995. One was an EBV-positive diffuse large B-cell lymphoma, 2 were EBV-positive Burkitt's lymphomas and the 4th was an EBV-negative Burkitt's lymphoma. Immunohistochemistry revealed expression of the EBV-encoded latent membrane protein LMP1 and of the BZLF1 trans-activator protein in 2 cases each, whereas the virus-encoded nuclear antigen EBNA2 was not detectable. All available post-transplant biopsies from the 3 patients with EBV-associated lymphoma were then studied to test whether the detection of EBV-positive cells in liver allograft biopsies could be used to identify patients at risk for the development of PTLD. Two patients showed infrequent EBV-positive cells in liver allograft biopsies up to 14 months before the occurrence of lymphoma and a marked increase in the number of such cells at the time of lymphoma diagnosis. Multiple biopsies from the 3rd patient did not reveal any EBV-carrying cells in the entire post-transplant period. Our results demonstrate a low incidence of PTLD in the Birmingham liver transplant programme. The PTLDs were morphologically high-grade malignant lymphomas. Only 3 cases were associated with EBV infection, and these showed heterogeneous patterns of EBV latent protein expression. Our results also suggest that the examination of liver allograft biopsies using EBER in situ hybridisation is not an appropriate method for identifying patients at risk of developing PTLD.
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PMID:Epstein-Barr virus infection and malignant lymphomas in liver transplant recipients. 938 65

The EBV plays a major role in the development of lymphoproliferative disorders in immunosuppressed patients. After organ transplantation most of lymphoproliferative disorders associated with EBV are polymorphic, with various expression of clonality. The pattern of EBV latency genes expression is rather the same as in lymphoblastoid cells lines and the EBV infected cells strongly expressed activation and adhesion molecules in most cases. In AIDS-related lymphomas the frequency of EBV as well as the expression of latency genes are related to the localization and to the histological subtypes. While EBV is observed in 30 to 50% of cases of Burkitt's lymphomas occurring the early stage of AIDS, its association in primary brain lymphomas and immunoblastic lymphomas developed in the late stage is observed in nearly all cases as well as in Hodgkin's disease. In primary brain lymphomas, the high expression of LMP-1 protein is correlated to the expression of BCL2 oncoprotein suggesting a transactivation of bcl2 by LMP-1 as it was reported in vitro. In non overt immunosuppressed patients the role of EBV is less clearly established, particularly in Burkitt's lymphoma where EBV is now considered as a cofactor. In B-cell lymphoma EBV is detected in about 5% of cases except in peculiar situations such as in lymphoma occurring in pleural cavity after longstanding pleural chronic inflammation and in Richter's syndrome with Reed-Sternberg-like cells. In peripheral T-cell lymphomas, EBV is observed in about 25% of cases, but its frequency varies with the histology and the localisation. EBV is present in nearly all cases of angio-immunoblastic type and in the nasal lymphoid proliferations developed from the NK cells. Detected in 30 to 80% in the Reed-Sternberg cells of Hodgkin's disease cases, the pathogenic significance of EBV remains to be determined in this disease.
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PMID:[Role of Epstein-Barr Virus in lymphoproliferative disorders]. 945 45

Efficient removal of lymphocytes undergoing programmed cell death (apoptosis) by macrophages plays an important role for the proper function of normal immune system. Furthermore, in malignant lymphoma, elimination of apoptotic tumor cells by phagocytes contributes to the anti-tumor immune response. It is unknown, however, whether macrophages in normal and malignant lymphoid tissues differ in their ability to recognize and remove apoptotic cells. Our present results demonstrate that normal and malignant lymphoid tissues differ according to the extent of the infiltration by macrophages. The highest densities of macrophages (p < 0.0001) were detected in diffuse large B-cell lymphoma, centroblastic (DLBCL-CB) and immunoblastic variants and Burkitt's lymphoma. The grade of the macrophage infiltration correlated with the proliferation rates of the tumors (p < 0.0001). Compared with normal lymphoid organs, malignant lymphoma contained lower percentages of apoptotic cells phagocytosed by tissue macrophages (p < 0.001). Of all lymphomas tested, mantle cell lymphoma and DLBCL-CB expressed the lowest percentages of phagocytosed apoptotic cells (p < 0.0001).
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PMID:Reduced phagocytosis of apoptotic cells in malignant lymphoma. 949 33

High-grade mucosa-associated lymphoid tissue (MALT) B-cell lymphoma of the stomach shares several features with its low-grade counterpart. The latter is nearly invariably associated with Helicobacter pylori, and the tumor cells of all MALT lymphomas normally express surface antigen receptors; thus, it is possible that the high-grade type, like the low-grade type, is still influenced by interaction with antigen. In the present study, we analyzed the immunoglobulin heavy chain variable (V)-region genes from eight cases of high-grade MALT lymphoma and one case of Burkitt's lymphoma of the stomach. The V-region genes revealed somatic mutations in all cases, leading to the conclusion that high-grade MALT lymphomas derive from antigen-experienced (post-) germinal center B-cells. Nonrandom distribution of replacement and silent mutations within the gene segments in seven of the eight MALT lymphomas indicated that these V-region genes were selected by antigen, at least for some period of time. Five of the cases showed an unusual mutation pattern that was suggestive of selection by autoantigen or superantigen rather than heterogeneous antigen. Analysis for intraclonal variations revealed evidence of ongoing mutations in two cases. In these cases, the tumor clones probably derived from cells affected by a germinal center B-cell reaction, as the microenvironment of the germinal center is required for maintenance of an active hypermutation mechanism. On the other hand, in another two cases, no evidence of intraclonal variations was found. Thus, either these tumor clones were derived from postgerminal center B-cells, or the hypermutation mechanism in the germinal center ceased after some period of time. Given the mutation pattern, it is possible that high-grade MALT lymphomas emerge from further transformation of low-grade MALT lymphomas with accumulation of additional mutations in the complementarity-determining regions.
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PMID:Immunoglobulin VH genes of high-grade mucosa-associated lymphoid tissue lymphomas show a high load of somatic mutations and evidence of antigen-dependent affinity maturation. 952 Sep 41

Many malignant lymphomas are characterized by recurrent genetic abnormalities. These include numerical abnormalities, deletions and reciprocal translocations. In this chapter, we have focused on the detection of chromosomal translocations in B cell lymphomas and discussed some trisomies in lymphomas and CLL. FISH is a well developed molecular method by which it is possible to detect numerical and structural chromosomal abnormalities. We addressed various aspects of metaphase, and especially interphase, FISH and also described the recently developed DNA fibre FISH technology. Using this method, it is possible simultaneously to detect and map chromosomal breakpoints. FISH is also compared with more conventional detection methods such as banding analysis, Southern blot analysis and PCR for the translocations t(8;14) and variant translocations in Burkitt's lymphoma, t(14;18) in follicular lymphoma and t(11;14) in MCL. Other breakpoints in B cell lymphoma are also discussed. It might be concluded that the rapid development in interphase and DNA fibre FISH will provide us with quick, easy and cheap tools to identify specific chromosomal translocations and other genomic abnormalities in human tumours.
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PMID:FISH and related techniques in the diagnosis of lymphoma. 954 83

Epstein-Barr virus (EBV) is distributed widely throughout the world. Apart from a association with two geographically-restricted malignancies (Burkitt's lymphoma and nasopharyngeal carcinoma), EBV is thought to be implicated in the etiology of B-cell lymphoma in immunocompromised individuals. In these patients, monitoring the viral load in serum can provide useful information on the timing of the instigation of antiviral therapy, i.e. as soon as a rise is detected. PCR technology, owing to its high sensitivity, is used frequently in such situations. In order to gain further insight into the nature of the peripheral blood cells carrying the viral genome on a cell-by-cell basis, an in situ amplification technique was developed as a model using two cell lines growing in suspension, with the aim of distinguishing between EBV-positive and EBV-negative cells. Preliminary experiments were undertaken subsequently on clinical samples from patients with infectious mononucleosis and patients with lymphoma indicating that this technique might be useful clinically.
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PMID:In situ amplification of the Epstein-Barr virus genome in cell suspensions. 962 54


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