| 1. |
- Giefing, Maciej, et al.
(författare)
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Loss of function mutations of BCOR in classical Hodgkin lymphoma
- 2022
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Ingår i: Leukemia and Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 63:5, s. 1080-1090
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Tidskriftsartikel (refereegranskat)abstract
- BCOR is a component of a variant Polycomb repressive complex 1 (PRC1.1). PRC1 and PRC2 complexes together constitute a major gene regulatory system critical for appropriate cellular differentiation. The gene is upregulated in germinal center (GC) B cells and mutated in a number of hematologic malignancies. We report BCOR inactivating alterations in 4/7 classic Hodgkin lymphoma (cHL) cell lines, subclonal somatic mutations in Hodgkin and Reed-Sternberg (HRS) cells of 4/10 cHL cases, and deletions in HRS cells of 7/17 primary cHL cases. In mice, conditional loss of Bcor driven by AID-Cre in GC B cells resulted in gene expression changes of 46 genes (>2-fold) including upregulated Lef1 that encodes a transcription factor responsible for establishing T-cell identity and Il9r (interleukin-9 receptor), an important member of the cytokine network in cHL. Our findings suggest a role for BCOR loss in cHL pathogenesis and GC-B cell homeostasis.
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| 2. |
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| 3. |
- Schneider, Markus, et al.
(författare)
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Alterations of the CD58 gene in classical Hodgkin lymphoma
- 2015
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 54:10, s. 638-645
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Tidskriftsartikel (refereegranskat)abstract
- Immune evasion plays a central role in the pathophysiology of classical Hodgkin lymphoma (cHL). As mutations of the CD58 gene contribute to immune evasion of diffuse large B cell lymphoma tumor cells, we studied whether alterations of the CD58 gene also occur in Hodgkin and Reed/Sternberg (HRS) cells of cHL. Single nucleotide polymorphism chip analysis revealed homozygous deletions within the CD58 gene in two cHL cell lines (SUP-HD1 and U-HO1). Sequencing of the CD58 gene in seven cHL cell lines disclosed in addition a homozygous splice site mutation in cell line KM-H2. None of the three mutated lines expressed CD58 protein on their surface. Thus, three of seven cHL cell lines analyzed harbor destructive CD58 mutations. Molecular analysis of isolated HRS cells from 10 primary cases of cHL; however, did not reveal any case with a CD58 mutation. A FICTION study indicated heterozygous deletions of CD58 in 3 of 13 cHL analyzed. Overall, we report frequent inactivating mutations of CD58 in cHL cell lines, but their rare occurrence in primary HRS cells. As the three cHL cell lines with CD58 mutations were all established from HRS cells located in pleural effusions, i.e., outside the normal lymph node microenvironment, in end-stages of the disease, CD58 inactivation in cHL might be predominantly prevalent to such situations.
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| 4. |
- Schwartz, Friederike H., et al.
(författare)
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TET2 mutations in B cells of patients affected by angioimmunoblastic T-cell lymphoma
- 2017
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Ingår i: Journal of Pathology. - : WILEY. - 0022-3417 .- 1096-9896. ; 242:2, s. 129-133
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Tidskriftsartikel (refereegranskat)abstract
- Angioimmunoblastic T-cell lymphomas (AITLs) frequently carry mutations in the TET2 and IDH2 genes. TET2 mutations represent early genetic lesions as they had already been detected in haematopoietic precursor cells of AITL patients. We show by analysis of whole-tissue sections and microdissected PD1(+) cells that the frequency of TET2-mutated AITL is presumably even higher than reported (12/13 cases in our collection; 92%). In two-thirds of informative AITLs (6/9), a fraction of B cells was also TET2-mutated. Investigation of four AITLs by TET2 and IGHV gene sequencing of single microdissected B cells showed that between 10% and 60% of polyclonal B cells in AITL lymph nodes harboured the identical TET2 mutations of the respective T-cell lymphoma clone. Thus, TET2-mutated haematopoietic precursor cells in AITL patients not only give rise to the T-cell lymphoma but also generate a large population of mutated mature B cells. Future studies will show whether this is a reason why AITL patients frequently also develop B-cell lymphomas. Copyright (C) 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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| 5. |
- Thurner, Lorenz, et al.
(författare)
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B-cell receptor reactivity against Rothia mucilaginosa in nodular lymphocyte-predominant Hodgkin lymphoma
- 2023
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Ingår i: Haematologica. - : Ferrata Storti Foundation. - 0390-6078 .- 1592-8721. ; 108:12, s. 3347-3358
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Tidskriftsartikel (refereegranskat)abstract
- Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a Hodgkin lymphoma expressing functional B-cell receptors (BCR). Recently, we described a dual stimulation model of IgD+ lymphocyte-predominant cells by Moraxella catarrhalis antigen RpoC and its superantigen MID/hag, associated with extralong CDR3 and HLA-DRB1*04 or HLA-DRB1*07 haplotype. The aim of the present study was to extend the antigen screening to further bacteria and viruses. The fragment antibody-binding (Fab) regions of seven new and 15 previously reported cases were analyzed. The reactivity of non-Moraxella spp.-reactive Fab regions against lysates of Rothia mucilaginosa was observed in 5/22 (22.7%) cases. Galactofuranosyl transferase (Gltf) and 2,3-butanediol dehydrogenase (Bdh) of R. mucilaginosa were identified by comparative silver-and immuno-staining in two-dimensional gels, with subsequent mass spectrometry and validation by western blots and enzyme-linked immunosorbent assay. Both R. mucilaginosa Gltf and Bdh induced BCR pathway activation and proliferation in vitro. Apoptosis was induced by recombinant Gltf/ETA'-immunotoxin conjugates in DEV cells expressing recombinant R. mucilaginosa-reactive BCR. Reactivity against M. catarrhalis RpoC was confirmed in 3/7 newly expressed BCR (total 10/22 reactive to Moraxella spp.), resulting in 15/22 (68.2%) cases with BCR reactivity against defined bacterial antigens. These findings strengthen the hypothesis of bacterial trigger contributing to subsets of NLPHL.
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| 6. |
- Thurner, Lorenz, et al.
(författare)
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Lymphocyte predominant cells detect Moraxella catarrhalis-derived antigens in nodular lymphocyte-predominant Hodgkin lymphoma
- 2020
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma of B-cell origin with frequent expression of functional B-cell receptors (BCRs). Here we report that expression cloning followed by antigen screening identifies DNA-directed RNA polymerase beta' (RpoC) from Moraxella catarrhalis as frequent antigen of BCRs of IgD(+) LP cells. Patients show predominance of HLA-DRB1*04/07 and the IgVH genes encode extraordinarily long CDR3s. High-titer, light-chain-restricted anti-RpoC IgG1/kappa -type serum-antibodies are additionally found in these patients. RpoC and MID/hag, a superantigen co-expressed by Moraxella catarrhalis that is known to activate IgD(+) B cells by binding to the Fc domain of IgD, have additive activation effects on the BCR, the NF-kappa B pathway and the proliferation of IgD(+) DEV cells expressing RpoC-specific BCRs. This suggests an additive antigenic and superantigenic stimulation of B cells with RpoC-specific IgD(+) BCRs under conditions of a permissive MHC-II haplotype as a model of NLPHL lymphomagenesis, implying future treatment strategies. Nodular lymphocyte-predominant Hodgkin lymphoma with IgD+ lymphocyte-predominant (LP) cells is a rare clinical distinct lymphoma subset of B-cell origin. Here the authors show that antigens expressed by Moraxella catarrhalis are recognized by B cell receptors of IgD+ LP cells, suggesting the contribution of chronic antigen stimulation to lymphomagenesis.
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