Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q06643 (non-Hodgkin's lymphoma)
 11,307 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twenty cases of B-cell non-Hodgkin's lymphoma (NHL) were evaluated by immunohistochemical staining of frozen sections with a panel of anti MHC class II monoclonal antibodies (MCA). These studies showed marked differences in the expression of class II antigens both between different cases and within the population of cells of individual cases. In all of the cases studied the majority of the tumour cells reacted with MCAs directed against determinants common to the products of SB and DR loci. However, MCAs specific for DC determinants failed to react with 3/20 cases and in several other cases stained only a minority of cells. Absent or reduced expression of DC antigens was most marked in lymphocytic lymphoma; however, in centroblastic-centrocytic and centroblastic lymphomas, DC antigens could be detected on the majority of cells.
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PMID:Immunohistochemical analysis of human MHC class II antigens in B-cell non-Hodgkin's lymphomas. 257 25

In this review we have summarized our experiences of serological analysis of MHC class II antigen expression in human B cell malignant disease. Cells from a large number of cases of B-cell chronic lymphocytic leukaemia (CLL) and non-Hodgkin's lymphoma (NHL) have been examined for expression of class II antigens. Using a number of monoclonal antibodies which in some cases are specific for class II subregion products (DP, DQ and DR), MHC class II antigens were detected by indirect immunofluorescence and fluorescent activated cell sorter analysis in CLL and by immunohistochemical staining in NHL. At the cell surface in many cases of B cell malignant disease, products of the different class II subregion genes are non-coordinately expressed. The most commonly occurring pattern of non-coordinate expression of class II molecules is of expression of DP and DR antigens in the absence of detectable DQ expression. These findings are in contrast to normal B lymphocytes where DP, DQ and DR antigens are expressed together at the cell surface. There is considerable heterogeneity among cases comprising individual histopathological categories of B cell malignancy, and in many instances heterogeneous class II phenotypes are also found on cells from the same tumour. In chronic lymphocytic leukaemia, class II antigen expression is inducible in vitro by treating the cells with the phorbol ester TPA. CLL cells treated with TPA have much increased levels of class II antigen expression at the cell surface and much increased steady state levels of class II specific mRNA transcripts detectable with complementary DNA probes. Aberrant class II antigen expression may be involved in the pathogenesis of B cell malignant disease.
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PMID:Expression of MHC class II antigens in human B-cell leukaemia and non-Hodgkin's lymphoma. 351 12

The bacterial superantigen staphylococcal enterotoxin A (SEA) is an efficient activator of cytotoxic T cells when presented on major histocompatibility complex (MHC) class II molecules of target cells. Our previous studies showed that such SEA-directed T cells efficiently lysed chronic B-lymphocytic leukemia (B-CLL) cells. Next, we made a mutated SEA-protein A (SEAm-PA) fusion protein with more than 1,000-fold reduced binding affinity for MHC class II compared with native SEA. The fusion protein was successfully used to direct T cells to B-CLL cells coated with different B lineage-directed monoclonal antibodies (MoAbs). In this communication, we constructed a recombinant anti-CD19-Fab-SEAm fusion protein. The MHC class II binding capacity of the SEA part was drastically reduced by a D227A point mutation, whereas the T-cell activation properties were retained. The Fab part of the fusion protein displayed a binding affinity for CD19+ cells in the nanomolar range. The anti-CD19-Fab-SEAm molecule mediated effective, specific, rapid, and perforin-like T-cell lysis of B-CLL cells at low effector to target cell ratios. Normal CD19+ B cells were sensitive to lysis, whereas CD34+ progenitor cells and monocytes/macrophages were resistant. A panel of CD19+ B-cell lines representing different B-cell developmental stages were efficiently lysed, and the sensitivity correlated with surface ICAM-1 expression. The anti-CD19-Fab-SEAm fusion protein mediated highly effective killing of tumor biopsy cells representing several types of B-cell non-Hodgkin's lymphoma (B-NHL). Humanized severe combined immune deficiency (SCID) mice carrying Daudi lymphoma cells were used as an in vivo therapy model for evaluation of the anti-CD19-Fab-SEAm fusion protein. Greater than 90% reduction in tumor weight was recorded in anti-CD19-Fab-SEAm-treated animals compared with control animals receiving an irrelevant Fab-SEAm fusion protein. The present results indicate that MoAb-targeted superantigens (SAgs) may represent a promising approach for T-cell-based therapy of CD19+ B-cell malignancies.
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PMID:A superantigen-antibody fusion protein for T-cell immunotherapy of human B-lineage malignancies. 905 31

From March 1994 to November 1994, 16 patients with high risk hematological malignancies were entered in a phase I clinical trial, designed to confirm the toxicity of cyclosporine and gamma interferon given to induce autologous graft-versus-host disease (GVHD) after autologous bone marrow transplantation (ABMT). This trial was based on the results in a rodent model, in which cyclosporine given after ABMT induces an autoimmune syndrome (autologous GVHD) identical to allogeneic GVHD. Further, this autologous GVHD is associated with a graft-versus-tumor effect augmented by interferon that upregulates MHC class II expression on normal and tumor cells, the target of the cytolytic T cells in autologous GVHD. In this trial, cyclosporine 1 mg/kg/day was given from the day of bone marrow reinfusion until the completion of the interferon and gamma-interferon. Gamma-interferon at 0.025 mg/m2 every other day was started when the total white cell count was >200 cells/ml for 2 consecutive days and continued for a total of 10 doses after ABMT. The preparative regimens were busulfan and cyclophosphamide, or cyclophosphamide with total body irradiation. All patients received 4HC-purged marrow grafts. Median age was 45 years (range 19-68). The diagnoses included chemo-resistant non-Hodgkin's lymphoma (10), acute lymphoblastic leukemia (two), chemo-resistant Hodgkin's disease (two), acute myeloid leukemia (one), and multiple myeloma (one). Median absolute neutrophil count recovery was 25.5 days (range 19-46 days). Median platelet count recovery was 40.5 days (range 28-279 days). There were nine deaths, two were related to transplant toxicity (infection), while the other seven were due to relapse. Event-free survival with a median of 964 days (range 19-1441 days of follow-up was 44%. In conclusion, treatment with cyclosporine, and gamma-interferon after ABMT was well tolerated and did not impair engraftment. Further studies with a larger number of patients are required to document any beneficial anti-tumor effect of autologous GVHD induction after ABMT.
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PMID:Immune modulation in autologous bone marrow transplantation: cyclosporine and gamma-interferon trial. 1049 Jul 29

CD74 is an integral membrane protein that functions as a MHC class II chaperone. Moreover, it has recently been shown to have a role as an accessory-signaling molecule and has been implicated in malignant B-cell proliferation and survival. These biological functions combined with expression of CD74 on malignant B cells and limited expression on normal tissues implicate CD74 as a potential therapeutic target. The anti-CD74 monoclonal antibody LL1 has been humanized (hLL1 milatuzumab or IMMU-115) and can provide the basis for novel therapeutic approaches to B-cell malignancies, particularly because this antibody shows rapid internalization into CD74+ malignant cells. This article reviews the preclinical evaluations of LL1, its humanized form, and isotope, drug, and toxin conjugates. These studies show that unconjugated hLL1 and conjugates of hLL1 constructs with radioisotopes, doxorubicin, and frog RNase have high antitumor activity in non-Hodgkin's lymphoma and multiple myeloma in vitro and in tumor xenograft models. Single-dose studies of hLL1 in monkeys showed no adverse effects but did decrease circulating B and T lymphocytes and natural killer cells. When evaluated in combination with rituximab, either equivalent or improved efficacy, compared with either antibody alone, was observed. CD74 is a new candidate target for the immunotherapy of neoplasms expressing this antigen, which can be exploited using either a naked antibody or conjugated to isotopes, drugs, or toxins.
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PMID:CD74: a new candidate target for the immunotherapy of B-cell neoplasms. 1787 89

Hepatitis C virus (HCV) which is one of the endemic viral infections in Egypt is not only hepatotropic, but also a lymphotropic virus and has many extrahepatic manifestations as mixed cryoglobulinemia and non-Hodgkin's lymphoma. We studied gene expression profile of 20 B-cell non-Hodgkin's lymphoma with HCV infection and 20 B-cell non-Hodgkin's lymphoma without HCV infection as a control group by c-DNA microarray. Out of the 15,500 studied genes, more than 1000 genes were differentially expressed; either upregulated or downregulated. We found that HCV may rescue B lymphocytes from apoptosis possibly through causing suppression of CASP1 and CASP4 and causing overexpression of the anti-apoptotic BCL2 gene. Also, HCV was associated with overexpression of the genes related to myeloid/lymphoid leukemia and B lymphoma as MLLT3, BAL, influences the overexpression of transcription regulator genes as TATA box binding protein (TBP) and may influence the overexpression of some immunoglobulin genes as immunoglobulin superfamily containing leucine gene in B cells resulting in overproduction of immunoglobulins in B-lymphocyte disorders. Moreover HCV was associated with reduced expression of MHC class II molecules in B lymphocytes, and therefore inhibition of antigen processing and presentation through downregulation of different MHC class II molecules genes. We conclude that the upregulated and the downregulated genes identified through the studied expression profiles of NHL with HCV infection may shed light on the mechanisms of HCV lymphomagenesis.
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PMID:Genetic profiling of non-Hodgkin's lymphoma with or without hepatitis C virus infection. 2308 89

Diffuse large B-cell lymphoma (DLBCL), the most common form of non-Hodgkin's lymphoma (NHL) diagnosed in the USA, consists of at least two distinct subtypes: germinal centre B (GCB) and activated B-cell (ABC). Decreased MHC class II (MHCII) expression on the tumours in both DLBCL subtypes directly correlates with significant decreases in patient survival. One common mechanism accounting for MHCII down-regulation in DLBCL is reduced expression of the MHC class II transactivator (CIITA), the master regulator of MHCII transcription. Furthermore, reduced CIITA expression in ABC DLBCL correlates with the presence of the transcriptional repressor positive regulatory domain-I-binding factor-1 (PRDI-BF1). However, the mechanisms underlying down-regulation of CIITA in GCB DLBCL are currently unclear. In this study, we demonstrate that neither PRDI-BF1 nor CpG hypermethylation at the CIITA promoters are responsible for decreased CIITA in GCB DLBCL. In contrast, histone modifications associated with an open chromatin conformation and active transcription were significantly lower at the CIITA promoters in CIITA(-) GCB cells compared with CIITA(+) B cells, which suggests that epigenetic mechanisms contribute to repression of CIITA transcription. Treatment of CIITA(-) or CIITA(low) GCB cells with several different histone deacetylase inhibitors (HDACi) activated modest CIITA and MHCII expression. However, CIITA and MHCII levels were significantly higher in these cells after exposure to the HDAC-1-specific inhibitor MS-275. These results suggest that CIITA transcription is repressed in GCB DLBCL cells through epigenetic mechanisms involving HDACs, and that HDACi treatment can alleviate repression. These observations may have important implications for patient therapy.
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PMID:Histone deacetylase inhibitors activate CIITA and MHC class II antigen expression in diffuse large B-cell lymphoma. 2378 44

Primary mediastinal large B cell lymphoma (PMBCL) is an aggressive non-Hodgkin's lymphoma, predominantly affecting young patients. We analyzed 45 primary PMBCL tumor biopsies and 3 PMBCL-derived cell lines for the presence of genetic alterations involving the major histocompatibility complex (MHC) class II transactivator CIITA and found frequent aberrations consisting of structural genomic rearrangements, missense, nonsense, and frame-shift mutations (53% of primary tumor biopsies and all cell lines). We also detected intron 1 mutations in 47% of the cases, and detailed sequence analysis strongly suggests AID-mediated aberrant somatic hypermutation as the mutational mechanism. Furthermore, we demonstrate that genomic lesions in CIITA result in decreased protein expression and reduction of MHC class II surface expression, creating an immune privilege phenotype in PMBCL. In summary, we establish CIITA alterations as a common mechanism of immune escape through reduction of MHC class II expression in PMBCL, with potential implications for future treatments targeting microenvironment-related biology.
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PMID:Genomic Alterations in CIITA Are Frequent in Primary Mediastinal Large B Cell Lymphoma and Are Associated with Diminished MHC Class II Expression. 2654 56