| 1. |
- Hadzidimitriou, Anastasia, et al.
(författare)
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Is there a role for antigen selection in mantle cell lymphoma? : Immunogenetic support from a series of 807 cases
- 2011
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 118:11, s. 3088-3095
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Tidskriftsartikel (refereegranskat)abstract
- We examined 807 productive IGHV-IGHD-IGHJ gene rearrangements from mantle cell lymphoma (MCL) cases, by far the largest series to date. The IGHV gene repertoire was remarkably biased, with IGHV3-21, IGHV4-34, IGHV1-8, and IGHV3-23 accounting for 46.3% of the cohort. Eighty-four of 807 (10.4%) cases, mainly using the IGHV3-21 and IGHV4-34 genes, were found to bear stereotyped heavy complementarity-determining region 3 (VH CDR3) sequences and were placed in 38 clusters. Notably, the MCL stereotypes were distinct from those reported for chronic lymphocytic leukemia. Based on somatic hypermutation (SHM) status, 238/807 sequences (29.5%) carried IGHV genes with 100% germ line identity; the remainder (569/807; 70.5%) exhibited different SHM impact, ranging from minimal (in most cases) to pronounced. Shared replacement mutations across the IGHV gene were identified for certain subgroups, especially those using IGHV3-21, IGHV1-8, and IGHV3-23. Comparison with other entities, in particular CLL, revealed that several of these mutations were "MCL-biased." In conclusion, MCL is characterized by a highly restricted immunoglobulin gene repertoire with stereotyped VH CDR3s and very precise SHM targeting, strongly implying a role for antigen-driven selection of the clonogenic progenitors. Hence, an antigen-driven origin of MCL could be envisaged, at least for subsets of cases.
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| 2. |
- Agathangelidis, Andreas, et al.
(författare)
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High-Throughput immunogenetics for precision medicine in cancer
- 2022
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Ingår i: Seminars in Cancer Biology. - : Elsevier. - 1044-579X .- 1096-3650. ; 84, s. 80-88
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Tidskriftsartikel (refereegranskat)abstract
- Cancer is characterized by an extremely complex biological background, which hinders personalized therapeutic interventions. Precision medicine promises to overcome this obstacle through integrating information from different 'subsystems', including the host, the external environment, the tumor itself and the tumor microenvironment. Immunogenetics is an essential tool that allows dissecting both lymphoid cancer ontogeny at both a cell-intrinsic and a cell-extrinsic level, i.e. through characterizing micro-environmental interactions, with a view to precision medicine. This is particularly thanks to the introduction of powerful, high-throughput approaches i.e. next generation sequencing, which allow the comprehensive characterization of immune repertoires. Indeed, NGS immunogenetic analysis (Immune-seq) has emerged as key to both understanding cancer pathogenesis and improving the accuracy of clinical decision making in oncology. Immune-seq has applications in lymphoid malignancies, assisting in the diagnosis e.g. through differentiating from reactive conditions, as well as in disease monitoring through accurate assessment of minimal residual disease. Moreover, Immune-seq facilitates the study of T cell receptor clonal dynamics in critical clinical contexts, including transplantation as well as innovative immunotherapy for solid cancers. The clinical utility of Immune-seq represents the focus of the present contribution, where we highlight what can be achieved but also what must be addressed in order to maximally realize the promise of Immune-seq in precision medicine in cancer.
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| 3. |
- Agathangelidis, Andreas, et al.
(författare)
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Highly similar genomic landscapes in monoclonal B-cell lymphocytosis and ultra-stable chronic lymphocytic leukemia with low frequency of driver mutations
- 2018
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 103:5, s. 865-873
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Tidskriftsartikel (refereegranskat)abstract
- Despite the recent discovery of recurrent driver mutations in chronic lymphocytic leukemia, the genetic factors involved in disease onset remain largely unknown. To address this issue, we per-formed whole-genome sequencing in 11 individuals with monoclonal B-cell lymphocytosis, both of the low-count and high-count subtypes, and 5 patients with ultra-stable chronic lymphocytic leukemia (>10 years without progression from initial diagnosis). All three entities were indistinguishable at the genomic level exhibiting low genomic complexity and similar types of somatic mutations. Exonic mutations were not frequently identified in putative chronic lymphocytic leukemia driver genes in all settings, including low-count monoclonal B-cell lymphocytosis. To corroborate these findings, we also performed deep sequencing in 11 known frequently mutated genes in an extended cohort of 28 monoclonal B-cell lym phocytosis/chronic lymphocytic leukemia cases. Interestingly, shared mutations were detected between clonal B cells and paired polymorphonuclear cells, strengthening the notion that at least a fraction of somatic mutations may occur before disease onset, likely at the hematopoietic stem cell level. Finally, we identified previously unreported non-coding variants targeting pathways relevant to B-cell and chronic lymphocytic leukemia development, likely associated with the acquisition of the characteristic neoplastic phenotype typical of both monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia.
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| 4. |
- Agathangelidis, Andreas, et al.
(författare)
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Immunoglobulin Gene Sequence Analysis In Chronic Lymphocytic Leukemia : From Patient Material To Sequence Interpretation
- 2018
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Ingår i: Journal of Visualized Experiments. - : JOURNAL OF VISUALIZED EXPERIMENTS. - 1940-087X. ; :141
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Tidskriftsartikel (refereegranskat)abstract
- During B cell maturation, the complex process of immunoglobulin (IG) gene V(D)J recombination coupled with somatic hypermutation (SHM) gives rise to a unique DNA sequence within each individual B cell. Since B cell malignancies result from the clonal expansion of a single cell, IG genes represent a unique molecular signature common to all the malignant cells within an individual patient; thus, IG gene rearrangements can be used as clonal markers. In addition to serving as an important clonal identifier, the IG gene sequence can act as a 'molecular timeline' since it is associated with specific developmental stages and hence reflects the history of the B cell involved in the neoplastic transformation. Moreover, for certain malignancies, in particular chronic lymphocytic leukemia (CLL), the IG gene sequence holds prognostic and potentially predictive capabilities. That said, extrapolating meaningful conclusions from IG gene sequence analysis would be impossible if robust methods and tools were not available to aid in their analysis. This article, drawing on the vast experience of the European Research Initiative on CLL (ERIC), details the technical aspects and essential requirements necessary to ensure reliable and reproducible IG gene sequence analysis in CLL, a test that is now recommended for all CLL patients prior to treatment. More specifically, the various analytical stages are described ranging from the identification of the clonotypic IG gene rearrangement and the determination of the nucleotide sequence to the accurate clinical interpretation of the IG gene sequence data.
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| 5. |
- Agathangelidis, Andreas, et al.
(författare)
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Stereotyped B-cell receptors in chronic lymphocytic leukemia
- 2014
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Ingår i: Leukemia and Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 55:10, s. 2252-2261
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Forskningsöversikt (refereegranskat)abstract
- Over the last decade, immunogenetic analysis of B-cell receptor immunoglobulins (BcR IGs) has proved to be a particularly fruitful field in chronic lymphocytic leukemia (CLL), not only for understanding disease pathogenesis but also for discriminating clinical subgroups with markedly distinct course and outcome. Of utmost importance was the identification of quasi-identical BcR IGs among unrelated patients with CLL, fittingly coined as "stereotypy," that set the wheels in motion for unraveling the role of antigen(s) in the selection and expansion of the leukemic clones. The categorization of CLL clones into "subsets" according to shared BcR IG structural characteristics provided a compartmentalized view of this otherwise heterogeneous disease, which eventually led to defining strikingly homogeneous groups of patients in terms of: (i) functional properties of the clonal BcR IGs, e. g. BcR reactivity and signaling; (ii) clonal genetic landscape, e. g. genomic aberrations, gene expression/methylation profiles, microRNA signatures; and (iii) clinical course and outcome. The remarkable restriction of the CLL IG gene repertoire, resulting to a great degree from the high impact of BcR IG stereotypy, may also prompt speculations regarding CLL ontogenesis. Overall, the BcR IG molecule justifiably lies at the heart of CLL clinical research, holding the promise of subset-tailored therapies.
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| 6. |
- Agathangelidis, Andreas, et al.
(författare)
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Stereotyped B-cell receptors in one-third of chronic lymphocytic leukemia : a molecular classification with implications for targeted therapies
- 2012
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 119:19, s. 4467-4475
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Tidskriftsartikel (refereegranskat)abstract
- Mounting evidence indicates that grouping of chronic lymphocytic leukemia (CLL) into distinct subsets with stereotyped BCRs is functionally and prognostically relevant. However, several issues need revisiting, including the criteria for identification of BCR stereotypy and its actual frequency as well as the identification of "CLL-biased" features in BCR Ig stereotypes. To this end, we examined 7596 Ig VH (IGHV-IGHD-IGHJ) sequences from 7424 CLL patients, 3 times the size of the largest published series, with an updated version of our purpose-built clustering algorithm. We document that CLL may be subdivided into 2 distinct categories: one with stereotyped and the other with nonstereotyped BCRs, at an approximate ratio of 1: 2, and provide evidence suggesting a different ontogeny for these 2 categories. We also show that subset-defining sequence patterns in CLL differ from those underlying BCR stereotypy in other B-cell malignancies. Notably, 19 major subsets contained from 20 to 213 sequences each, collectively accounting for 943 sequences or one-eighth of the cohort. Hence, this compartmentalized examination of VH sequences may pave the way toward a molecular classification of CLL with implications for targeted therapeutic interventions, applicable to a significant number of patients assigned to the same subset.
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| 7. |
- Agathangelidis, Andreas, et al.
(författare)
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Unlocking the secrets of immunoglobulin receptors in mantle cell lymphoma : Implications for the origin and selection of the malignant cells
- 2011
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Ingår i: Seminars in Cancer Biology. - : Elsevier BV. - 1044-579X .- 1096-3650. ; 21:5, s. 299-307
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Forskningsöversikt (refereegranskat)abstract
- Immunogenetic analysis of mantle cell lymphoma (MCL) has offered important evidence helping to decipher the immune pathways leading to its development and also prompting a reappraisal of the views about its ontogeny. In particular, older and more recent studies have demonstrated that MCL is characterized by a highly distinctive immunoglobulin gene repertoire with remarkable predominance of the IGHV3-21 and IGHV4-34 genes; restricted associations of IGHV,IGHD and IGHJ genes, culminating in the creation of quasi-identical ("stereotyped") heavy complementarity-determining region 3 sequences in roughly 10% of cases; and, very precisely targeted and, probably, functionally driven somatic hypermutation, ranging from minimal (in most cases) to pronounced. Furthermore, comparison to other entities, in particular CLL, revealed that several of these immunogenetic features are "MCL-biased". On these grounds, an antigen-driven origin of MCL could be envisaged, at least for subsets of cases.
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| 8. |
- Baliakas, Panagiotis, et al.
(författare)
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Clinical effect of stereotyped B-cell receptor immunoglobulins in chronic lymphocytic leukaemia: a retrospective multicentre study
- 2014
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Ingår i: The Lancet Haematology. - 2352-3026. ; 1:2, s. 74-84
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Tidskriftsartikel (refereegranskat)abstract
- Background About 30% of cases of chronic lymphocytic leukaemia (CLL) carry quasi-identical B-cell receptor immunoglobulins and can be assigned to distinct stereotyped subsets. Although preliminary evidence suggests that B-cell receptor immunoglobulin stereotypy is relevant from a clinical viewpoint, this aspect has never been explored in a systematic manner or in a cohort of adequate size that would enable clinical conclusions to be drawn. Methods For this retrospective, multicentre study, we analysed 8593 patients with CLL for whom immunogenetic data were available. These patients were followed up in 15 academic institutions throughout Europe (in Czech Republic, Denmark, France, Greece, Italy, Netherlands, Sweden, and the UK) and the USA, and data were collected between June 1, 2012, and June 7, 2013. We retrospectively assessed the clinical implications of CLL B-cell receptor immunoglobulin stereotypy, with a particular focus on 14 major stereotyped subsets comprising cases expressing unmutated (U-CLL) or mutated (M-CLL) immunoglobulin heavy chain variable genes. The primary outcome of our analysis was time to first treatment, defined as the time between diagnosis and date of first treatment. Findings 2878 patients were assigned to a stereotyped subset, of which 1122 patients belonged to one of 14 major subsets. Stereotyped subsets showed significant differences in terms of age, sex, disease burden at diagnosis, CD38 expression, and cytogenetic aberrations of prognostic significance. Patients within a specific subset generally followed the same clinical course, whereas patients in different stereotyped subsets-despite having the same immunoglobulin heavy variable gene and displaying similar immunoglobulin mutational status-showed substantially different times to first treatment. By integrating B-cell receptor immunoglobulin stereotypy (for subsets 1, 2, and 4) into the well established Dohner cytogenetic prognostic model, we showed these, which collectively account for around 7% of all cases of CLL and represent both U-CLL and M-CLL, constituted separate clinical entities, ranging from very indolent (subset 4) to aggressive disease (subsets 1 and 2). Interpretation The molecular classification of chronic lymphocytic leukaemia based on B-cell receptor immunoglobulin stereotypy improves the Dohner hierarchical model and refines prognostication beyond immunoglobulin mutational status, with potential implications for clinical decision making, especially within prospective clinical trials.
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| 9. |
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| 10. |
- Baliakas, Panagiotis, et al.
(författare)
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Not all IGHV3-21 chronic lymphocytic leukemias are equal: prognostic considerations.
- 2015
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Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 125:5, s. 856-859
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Tidskriftsartikel (refereegranskat)abstract
- An unresolved issue in chronic lymphocytic leukemia (CLL) is whether IGHV3-21 gene usage, in general, or the expression of stereotyped B-cell receptor immunoglobulin defining subset #2 (IGHV3-21/IGLV3-21), in particular, determines outcome for IGHV3-21-utilizing cases. We reappraised this issue in 8593 CLL patients of whom 437 (5%) used the IGHV3-21 gene with 254/437 (58%) classified as subset #2. Within subset #2, immunoglobulin heavy variable (IGHV)-mutated cases predominated, whereas non-subset #2/IGHV3-21 was enriched for IGHV-unmutated cases (P = .002). Subset #2 exhibited significantly shorter time-to-first-treatment (TTFT) compared with non-subset #2/IGHV3-21 (22 vs 60 months, P = .001). No such difference was observed between non-subset #2/IGHV3-21 vs the remaining CLL with similar IGHV mutational status. In conclusion, IGHV3-21 CLL should not be axiomatically considered a homogeneous entity with adverse prognosis, given that only subset #2 emerges as uniformly aggressive, contrasting non-subset #2/IGVH3-21 patients whose prognosis depends on IGHV mutational status as the remaining CLL.
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| 11. |
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| 12. |
- Baliakas, Panagiotis, 1977-, et al.
(författare)
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Tailored approaches grounded on immunogenetic features for refined prognostication in chronic lymphocytic leukemia
- 2019
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 1592-8721 .- 0390-6078. ; 104:2, s. 360-369
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Tidskriftsartikel (refereegranskat)abstract
- Chronic lymphocytic leukemia (CLL) patients with differential somatic hypermutation status of the immunoglobulin heavy variable genes, namely mutated or unmutated, display fundamental clinico-biological differences. Considering this, we assessed prognosis separately within mutated (M-CLL) and unmutated (U-CLL) CLL in 3015 patients, hypothesizing that the relative significance of relevant indicators may differ between these two categories. Within Binet A M-CLL patients, besides TP53 abnormalities, trisomy 12 and stereotyped subset #2 membership were equivalently associated with the shortest time-to-first-treatment and a treatment probability at five and ten years after diagnosis of 40% and 55%, respectively; the remaining cases exhibited 5-year and 10-year treatment probability of 12% and 25%, respectively. Within Binet A U-CLL patients, besides TP53 abnormalities, del(11q) and/or SF3B1 mutations were associated with the shortest time-to-first-treatment (5- and 10-year treatment probability: 78% and 98%, respectively); in the remaining cases, males had a significantly worse prognosis than females. In conclusion, the relative weight of indicators that can accurately risk stratify early-stage CLL patients differs depending on the somatic hypermutation status of the immunoglobulin heavy variable genes of each patient. This finding highlights the fact that compartmentalized approaches based on immunogenetic features are necessary to refine and tailor prognostication in CLL.
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| 13. |
- Bikos, Vasilis, et al.
(författare)
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An Immunogenetic Signature of Ongoing Antigen Interactions in Splenic Marginal Zone Lymphoma Expressing IGHV1-2*04 Receptors
- 2016
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 22:8, s. 2032-2040
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Prompted by the extensive biases in the immunoglobulin (IG) gene repertoire of splenic marginal-zone lymphoma (SMZL), supporting antigen selection in SMZL ontogeny, we sought to investigate whether antigen involvement is also relevant post-transformation. Experimental Design: We conducted a large-scale subcloning study of the IG rearrangements of 40 SMZL cases aimed at assessing intraclonal diversification (ID) due to ongoing somatic hypermutation (SHM). Results: ID was identified in 17 of 21 (81%) rearrangements using the immunoglobulin heavy variable (IGHV) 1-2*04 gene versus 8 of 19 (40%) rearrangements utilizing other IGHV genes (P = 0.001). ID was also evident in most analyzed IG light chain gene rearrangements, albeit was more limited compared with IG heavy chains. Identical sequence changes were shared by subclones from different patients utilizing the IGHV1-2*04 gene, confirming restricted ongoing SHM profiles. Non-IGHV1-2*04 cases displayed both a lower number of ongoing SHMs and a lack of shared mutations (per group of cases utilizing the same IGHV gene). Conclusions: These findings support ongoing antigen involvement in a sizable portion of SMZL and further argue that IGHV1-2*04 SMZL may represent a distinct molecular subtype of the disease.
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| 14. |
- Bystry, Vojtech, et al.
(författare)
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ARResT/AssignSubsets : a novel application for robust subclassification of chronic lymphocytic leukemia based on B cell receptor IG stereotypy
- 2015
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Ingår i: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811. ; 31:23, s. 3844-3846
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Tidskriftsartikel (refereegranskat)abstract
- Motivation: An ever-increasing body of evidence supports the importance of B cell receptor immunoglobulin (BcR IG) sequence restriction, alias stereotypy, in chronic lymphocytic leukemia (CLL). This phenomenon accounts for similar to 30% of studied cases, one in eight of which belong to major subsets, and extends beyond restricted sequence patterns to shared biologic and clinical characteristics and, generally, outcome. Thus, the robust assignment of new cases to major CLL subsets is a critical, and yet unmet, requirement. Results: We introduce a novel application, ARResT/AssignSubsets, which enables the robust assignment of BcR IG sequences from CLL patients to major stereotyped subsets. ARResT/AssignSubsets uniquely combines expert immunogenetic sequence annotation from IMGT/V-QUEST with curation to safeguard quality, statistical modeling of sequence features from more than 7500 CLL patients, and results from multiple perspectives to allow for both objective and subjective assessment. We validated our approach on the learning set, and evaluated its real-world applicability on a new representative dataset comprising 459 sequences from a single institution.
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| 15. |
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| 16. |
- Ghia, Paolo, et al.
(författare)
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Crystallographic evidence of autologous recognition by a clonotypic B cell receptor in chronic lymphocytic leukemia
- 2015
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Ingår i: Leukemia and Lymphoma. - IRCCS Sci Inst San Raffaele, Div Expt Oncol, Milan, Italy. [Degano, Massimo] IRCCS Sci Inst San Raffaele, Dept Immunol Transplantat & Infect Dis, Biocrystallog Unit, Milan, Italy. [Duehren-von Minden, Marcus; Schneider, Dunja; Alkhatib, Alabbas] Univ Freiburg, Ctr Biol Signaling Studies, Fac Biol, D-79106 Freiburg, Germany. [Belhart, Rudolf; Jumaa, Hassan] Univ Ulm Klinikum, Ulm, Germany. [Ntoufa, Stavroula; Stamatopoulos, Kostas] Ctr Res & Technol, Inst Appl Biosci, Thessaloniki, Greece. [Chiorazzi, Nicholas] Feinstein Inst Med Res, Manhasset, NY USA. [Stamatopoulos, Kostas] Uppsala Univ, Dept Immunol Genet & Pathol, Uppsala, Sweden. [Ghia, Paolo] Univ Milan, Osped San Raffaele, Dept Oncohematol, I-20127 Milan, Italy. [Ghia, Paolo] Univ Vita Salute San Raffaele, Milan, Italy.. - 1042-8194 .- 1029-2403. ; 56:S1, s. 110-111
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 17. |
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| 18. |
- Kavakiotis, Ioannis, et al.
(författare)
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Integrating multiple immunogenetic data sources for feature extraction and mining somatic hypermutation patterns : the case of "towards analysis" in chronic lymphocytic leukaemia
- 2016
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Ingår i: BMC Bioinformatics. - : Springer Science and Business Media LLC. - 1471-2105. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: Somatic Hypermutation (SHM) refers to the introduction of mutations within rearranged V(D)J genes, a process that increases the diversity of Immunoglobulins (IGs). The analysis of SHM has offered critical insight into the physiology and pathology of B cells, leading to strong prognostication markers for clinical outcome in chronic lymphocytic leukaemia (CLL), the most frequent adult B-cell malignancy. In this paper we present a methodology for integrating multiple immunogenetic and clinocobiological data sources in order to extract features and create high quality datasets for SHM analysis in IG receptors of CLL patients. This dataset is used as the basis for a higher level integration procedure, inspired form social choice theory. This is applied in the Towards Analysis, our attempt to investigate the potential ontogenetic transformation of genes belonging to specific stereotyped CLL subsets towards other genes or gene families, through SHM. Results: The data integration process, followed by feature extraction, resulted in the generation of a dataset containing information about mutations occurring through SHM. The Towards analysis performed on the integrated dataset applying voting techniques, revealed the distinct behaviour of subset #201 compared to other subsets, as regards SHM related movements among gene clans, both in allele-conserved and non-conserved gene areas. With respect to movement between genes, a high percentage movement towards pseudo genes was found in all CLL subsets. Conclusions: This data integration and feature extraction process can set the basis for exploratory analysis or a fully automated computational data mining approach on many as yet unanswered, clinically relevant biological questions.
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| 19. |
- Kolijn, P. Martijn, et al.
(författare)
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Consistent B Cell Receptor Immunoglobulin Features Between Siblings in Familial Chronic Lymphocytic Leukemia
- 2021
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Ingår i: Frontiers in Oncology. - : Frontiers Media S.A.. - 2234-943X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Key processes in the onset and evolution of chronic lymphocytic leukemia (CLL) are thought to include chronic (antigenic) activation of mature B cells through the B cell receptor (BcR), signals from the microenvironment, and acquisition of genetic alterations. Here we describe three families in which two or more siblings were affected by CLL. We investigated whether there are immunogenetic similarities in the leukemia-specific immunoglobulin heavy (IGH) and light (IGL/IGK) chain gene rearrangements of the siblings in each family. Furthermore, we performed array analysis to study if similarities in CLL-associated chromosomal aberrations are present within each family and screened for somatic mutations using paired tumor/normal whole-genome sequencing (WGS). In two families a consistent IGHV gene mutational status (one IGHV-unmutated, one IGHV-mutated) was observed. Intriguingly, the third family with four affected siblings was characterized by usage of the lambda IGLV3-21 gene, with the hallmark R110 mutation of the recently described clinically aggressive IGLV3-21(R110) subset. In this family, the CLL-specific rearrangements in two siblings could be assigned to either stereotyped subset #2 or the immunogenetically related subset #169, both of which belong to the broader IGLV3-21(R110) subgroup. Consistent patterns of cytogenetic aberrations were encountered in all three families. Furthermore, the CLL clones carried somatic mutations previously associated with IGHV mutational status, cytogenetic aberrations and stereotyped subsets, respectively. From these findings, we conclude that similarities in immunogenetic characteristics in familial CLL, in combination with genetic aberrations acquired, point towards shared underlying mechanisms behind CLL development within each family.
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| 20. |
- Kolijn, P. Martijn, et al.
(författare)
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High-risk subtypes of chronic lymphocytic leukemia are detectable as early as 16 years prior to diagnosis
- 2022
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 139:10, s. 1557-1563
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Tidskriftsartikel (refereegranskat)abstract
- Chronic lymphocytic leukemia (CLL) is preceded by monoclonal B-cell lymphocytosis (MBL), a CLL precursor state with a prevalence of up to 12% in aged individuals; however, the duration of MBL and the mechanisms of its evolution to CLL remain largely unknown. In this study, we sequenced the B-cell receptor (BcR) immunoglobulin heavy chain (IGH) gene repertoire of 124 patients with CLL and 118 matched controls in blood samples taken up to 22 years prior to diagnosis. Significant skewing in the BcR IGH gene repertoire was detected in the majority of patients, even before the occurrence of lymphocytosis and irrespective of the clonotypic IGH variable gene somatic hypermutation status. Furthermore, we identified dominant clonotypes belonging to major stereotyped subsets associated with poor prognosis up to 16 years before diagnosis in 14 patients with CLL. In 22 patients with longitudinal samples, the skewing of the BcR IGH gene repertoire increased significantly over time to diagnosis or remained stable at high levels. For 14 of 16 patients with available samples at diagnosis, the CLL clonotype was already present in the prediagnostic samples. Overall, our data indicate that the preclinical phase of CLL could be longer than previously thought, even in adverse-prognostic cases.
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| 21. |
- Ljungström, Viktor, et al.
(författare)
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Whole-exome sequencing in relapsing chronic lymphocytic leukemia : clinical impact of recurrent RPS15 mutations
- 2016
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Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 127:8, s. 1007-1016
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Tidskriftsartikel (refereegranskat)abstract
- Fludarabine, cyclophosphamide and rituximab (FCR) is first-line treatment for medically fit chronic lymphocytic leukemia (CLL) patients, however despite good response rates many patients eventually relapse. Whilst recent high-throughput studies have identified novel recurrent genetic lesions in adverse-prognostic CLL, the mechanisms leading to relapse after FCR therapy are not completely understood. To gain insight into this issue, we performed whole-exome sequencing of sequential samples from 41 CLL patients who were uniformly treated with FCR but relapsed after a median of 2 years. In addition to mutations with known adverse-prognostic impact (TP53, NOTCH1, ATM, SF3B1, NFKBIE, BIRC3) a large proportion of cases (19.5%) harbored mutations in RPS15, a gene encoding a component of the 40S ribosomal subunit. Extended screening, totaling 1119 patients, supported a role for RPS15 mutations in aggressive CLL, with one-third of RPS15-mutant cases also carrying TP53 aberrations. In most cases selection of dominant, relapse-specific subclones was observed over time. However, RPS15 mutations were clonal prior to treatment and remained stable at relapse. Notably, all RPS15 mutations represented somatic missense variants and resided within a 7 amino-acid evolutionarily conserved region. We confirmed the recently postulated direct interaction between RPS15 and MDM2/MDMX and transient expression of mutant RPS15 revealed defective regulation of endogenous p53 compared to wildtype RPS15. In summary, we provide novel insights into the heterogeneous genetic landscape of CLL relapsing after FCR treatment and highlight a novel mechanism underlying clinical aggressiveness involving a mutated ribosomal protein, potentially representing an early genetic lesion in CLL pathobiology.
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| 22. |
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| 23. |
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| 24. |
- Minici, Claudia, et al.
(författare)
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Distinct homotypic B-cell receptor interactions shape the outcome of chronic lymphocytic leukaemia
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Cell-autonomous B-cell receptor (BcR)-mediated signalling is a hallmark feature of the neoplastic B lymphocytes in chronic lymphocytic leukaemia (CLL). Here we elucidate the structural basis of autonomous activation of CLL B cells, showing that BcR immunoglobulins initiate intracellular signalling through homotypic interactions between epitopes that are specific for each subgroup of patients with homogeneous clinicobiological profiles. The molecular details of the BcR-BcR interactions apparently dictate the clinical course of disease, with stronger affinities and longer half-lives in indolent cases, and weaker, short-lived contacts mediating the aggressive ones. The diversity of homotypic BcR contacts leading to cell-autonomous signalling reconciles the existence of a shared pathogenic mechanism with the biological and clinical heterogeneity of CLL and offers opportunities for innovative treatment strategies.
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| 25. |
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| 26. |
- Papakonstantinou, Nikos, et al.
(författare)
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The histone methyltransferase EZH2 as a novel prosurvival factor in clinically aggressive chronic lymphocytic leukemia
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:24, s. 35946-35959
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Tidskriftsartikel (refereegranskat)abstract
- The histone methyltransferase EZH2 induces gene repression through trimethylation of histone H3 at lysine 27 (H3K27me3). EZH2 overexpression has been reported in many types of cancer and associated with poor prognosis. Here we investigated the expression and functionality of EZH2 in chronic lymphocytic leukemia (CLL). Aggressive cases with unmutated IGHV genes (U-CLL) displayed significantly higher EZH2 expression compared to indolent CLL cases with mutated IGHV genes (M-CLL); furthermore, in U-CLL EZH2 expression was upregulated with disease progression. Within U-CLL, EZH2(high) cases harbored significantly fewer (p = 0.033) TP53 gene abnormalities compared to EZH2(low) cases. EZH2(high) cases displayed high H3K27me3 levels and increased viability suggesting that EZH2 is functional and likely confers a survival advantage to CLL cells. This argument was further supported by siRNA-mediated downmodulation of EZH2 which resulted in increased apoptosis. Notably, at the intraclonal level, cell proliferation was significantly associated with EZH2 expression. Treatment of primary CLL cells with EZH2 inhibitors induced downregulation of H3K27me3 levels leading to increased cell apoptosis. In conclusion, EZH2 is overexpressed in adverse-prognosis CLL and associated with increased cell survival and proliferation. Pharmacologic inhibition of EZH2 catalytic activity promotes apoptosis, highlighting EZH2 as a novel potential therapeutic target for specific subgroups of patients with CLL.
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| 27. |
- Polychronidou, Eleftheria, et al.
(författare)
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Automated shape-based clustering of 3D immunoglobulin protein structures in chronic lymphocytic leukemia
- 2018
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Ingår i: BMC Bioinformatics. - : Springer Science and Business Media LLC. - 1471-2105. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Background: Although the etiology of chronic lymphocytic leukemia (CLL), the most common type of adult leukemia, is still unclear, strong evidence implicates antigen involvement in disease ontogeny and evolution. Primary and 3D structure analysis has been utilised in order to discover indications of antigenic pressure. The latter has been mostly based on the 3D models of the clonotypic B cell receptor immunoglobulin (BcR IG) amino acid sequences. Therefore, their accuracy is directly dependent on the quality of the model construction algorithms and the specific methods used to compare the ensuing models. Thus far, reliable and robust methods that can group the IG 3D models based on their structural characteristics are missing. Results: Here we propose a novel method for clustering a set of proteins based on their 3D structure focusing on 3D structures of BcR IG from a large series of patients with CLL. The method combines techniques from the areas of bioinformatics, 3D object recognition and machine learning. The clustering procedure is based on the extraction of 3D descriptors, encoding various properties of the local and global geometrical structure of the proteins. The descriptors are extracted from aligned pairs of proteins. A combination of individual 3D descriptors is also used as an additional method. The comparison of the automatically generated clusters to manual annotation by experts shows an increased accuracy when using the 3D descriptors compared to plain bioinformatics-based comparison. The accuracy is increased even more when using the combination of 3D descriptors. Conclusions: The experimental results verify that the use of 3D descriptors commonly used for 3D object recognition can be effectively applied to distinguishing structural differences of proteins. The proposed approach can be applied to provide hints for the existence of structural groups in a large set of unannotated BcR IG protein files in both CLL and, by logical extension, other contexts where it is relevant to characterize BcR IG structural similarity. The method does not present any limitations in application and can be extended to other types of proteins.
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| 28. |
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| 29. |
- Pouliou, Evi, et al.
(författare)
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Numerous Ontogenetic Roads to Mantle Cell Lymphoma : Immunogenetic and Immunohistochemical Evidence
- 2017
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Ingår i: American Journal of Pathology. - : ELSEVIER SCIENCE INC. - 0002-9440 .- 1525-2191. ; 187:7, s. 1454-1458
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Tidskriftsartikel (refereegranskat)abstract
- To obtain insight into the ontogeny of mantle cell lymphoma (MCL), we assessed 206 patients from a morphological, immunohistochemical, and immunogenetic perspective. Our series included nodal (n = 151), extranodal. (n = 28), and primary splenic (n = 27) MCL cases. Skewing of the immunoglobulin heavy variable (IGHV) gene repertoire was noted, with only four IGHV genes accounting for 46% of cases and approximately 70% of cases (107/154) bearing an imprint of somatic hypermutation (SHM) ranging from minimalto pronounced. Interestingly, a distinctive immunophenotypic and immunogenetic profile was identified for primary splenic MCL, which was enriched for DBA.44-positive cases (P < 0.001) and used the IGHV1-8 gene more frequently (P = 0.02) compared to nodal or extranodal cases, alluding to distinct immunopathogenetic and antigen selection processes. Expression of CD27 (considered a marker of activated B cells) was generally dissociated from SHM and was more prevalent in cases with no or minimal/borderline SHM. These findings support the idea that antigen drive is relevant for most MCL cases, although the specific antigens and the precise location of affinity maturation remain to be elucidated. Moreover, they raise the intriguing hypothesis of multiple cellular origins for MCL.
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| 30. |
- Sutton, Lesley-Ann, et al.
(författare)
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Antigen selection in B-cell lymphomas : tracing the evidence
- 2013
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Ingår i: Seminars in Cancer Biology. - : Elsevier BV. - 1044-579X .- 1096-3650. ; 23:6, s. 399-409
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Forskningsöversikt (refereegranskat)abstract
- While signaling through the B cell receptor (BcR) facilitates B cell development and maintenance, it also carries intertwined risks for the development of lymphomas since malignant B cells can exploit these pathways in order to trigger and fuel clonal expansion. This corruption of the normal B cell response to antigens, leading to sustained BcR signaling, has given great impulse to investigate in detail the role of antigen in lymphomas. Suffice it to conclude from such studies, largely immunogenetics based, that the evidence implicating antigens (exogenous or self) in lymphoma development is substantial and that lymphomagenesis is functionally driven and dynamic, rather than a simple stochastic process. As the paradigm of antigen-driven lymphoma evolves, further investigation will be paramount to the identification of the inciting agent(s) that may be responsible for immunoproliferative neoplasms and also for the development of therapeutic agents targeting effectors of the BcR signaling pathway.
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| 31. |
- Sutton, Lesley-Ann, et al.
(författare)
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Different spectra of recurrent gene mutations in subsets of chronic lymphocytic leukemia harboring stereotyped B-cell receptors
- 2016
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Ingår i: Haematologica. - : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 101:8, s. 959-967
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Tidskriftsartikel (refereegranskat)abstract
- We report on markedly different frequencies of genetic lesions within subsets of chronic lymphocytic leukemia patients carrying mutated or unmutated stereotyped B-cell receptor immunoglobulins in the largest cohort (n=565) studied for this purpose. By combining data on recurrent gene mutations (BIRC3, MYD88, NOTCH1, SF3B1 and TP53) and cytogenetic aberrations, we reveal a subset-biased acquisition of gene mutations. More specifically, the frequency of NOTCH1 mutations was found to be enriched in subsets expressing unmutated immunoglobulin genes, i.e. #1, #6, #8 and #59 (22-34%), often in association with trisomy 12, and was significantly different (P<0.001) to the frequency observed in subset #2 (4%, aggressive disease, variable somatic hypermutation status) and subset #4 (1%, indolent disease, mutated immunoglobulin genes). Interestingly, subsets harboring a high frequency of NOTCH1 mutations were found to carry few (if any) SF3B1 mutations. This starkly contrasts with subsets #2 and #3 where, despite their immunogenetic differences, SF3B1 mutations occurred in 45% and 46% of cases, respectively. In addition, mutations within TP53, whilst enriched in subset #1 (16%), were rare in subsets# 2 and #8 (both 2%), despite all being clinically aggressive. All subsets were negative for MYD88 mutations, whereas BIRC3 mutations were infrequent. Collectively, this striking bias and skewed distribution of mutations and cytogenetic aberrations within specific chronic lymphocytic leukemia subsets implies that the mechanisms underlying clinical aggressiveness are not uniform, but rather support the existence of distinct genetic pathways of clonal evolution governed by a particular stereotyped B-cell receptor selecting a certain molecular lesion(s).
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Vardi, Anna, et al.
(författare)
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Antigen Selection Shapes the T-cell Repertoire in Chronic Lymphocytic Leukemia
- 2016
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 22:1, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The role of antigen(s) in shaping the T-cell repertoire in chronic lymphocytic leukemia, although relevant for understanding malignant cell interactions with cognate T cells, is largely unexplored. Experimental Design: Here we profiled the T-cell receptor beta chain gene repertoire in 58 chronic lymphocytic leukemia patients, focusing on cases assigned to well-characterized subsets with stereotyped clonotypic B-cell receptor immunoglobulins, therefore those cases most evidently selected by antigen (subsets #1, #2, and #4). Results: Remarkable repertoire skewing and oligoclonality were observed, and differences between subsets were noted regarding both T-cell receptor b chain gene usage and the extent of clonality, with subset #2 being the least oligoclonal. Longitudinal analysis of subset #4 cases revealed that although the repertoire may fluctuate over time, certain clonotypes persist, thus alluding to persistent antigenic stimulation. Shared ("stereotyped") clonotypes were found between different patients, reflecting selection by common antigenic elements. Cross-comparison of our dataset with public databases showed that some T-cell clonotypes may have expanded secondary to common viral infections; however, the majority of clonotypes proved to be disease-specific. Conclusions: Overall, the T-cell receptor b chain repertoire in chronic lymphocytic leukemia is likely shaped by antigen selection and the implicated antigenic elements may concern epitopes that also select the malignant B-cell progenitors or, more intriguingly, chronic lymphocytic leukemia-derived epitopes.
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| 36. |
- Vardi, Anna, et al.
(författare)
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IgG-Switched CLL Has a Distinct Immunogenetic Signature from the Common MD Variant : Ontogenetic Implications
- 2014
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 20:2, s. 323-330
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:IgG-switched chronic lymphocytic leukemia (G-CLL) is a rare variant of CLL, whose origin and ontogenetic relationship to the common IgM/IgD (MD-CLL) variant remains undefined. Here we sought for clues regarding the ontogeny of G-CLL versus MD-CLL by profiling the relevant IG gene repertoires.EXPERIMENTAL DESIGN:Using purpose-built bioinformatics methods, we performed detailed immunogenetic profiling of a multinational CLL cohort comprising 1256 cases, of which 1087 and 169 expressed IG mu/delta and gamma heavy chains, respectively.RESULTS:G-CLL has a highly skewed IG gene repertoire that is distinct from MD-CLL, especially in terms of: (i) overuse of the IGHV4-34 and IGHV4-39 genes; and, (ii) differential somatic hypermutation (SHM) load. Repertoire differences held also when comparing subgroups with similar SHM status and were mainly attributed to the exclusive representation in G-CLL of two major subsets with quasi-identical (stereotyped) B-cell receptors. These subsets, namely #4 (IGHV4-34/IGKV2-30) and #8 (IGHV4-39/IGKV1(D)-39), were found to display sharply contrasting SHM and clinical behavior.CONCLUSIONS:G-CLL exhibits an overall distinct immunogenetic signature from MD-CLL, prompting speculations about distinct ontogenetic derivation and/or immune triggering. The reasons underlying the differential regulation of SHM among G-CLL cases remain to be elucidated.
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| 37. |
- Vardi, Anna, et al.
(författare)
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Immunogenetic Studies of Chronic Lymphocytic Leukemia : Revelations and Speculations about Ontogeny and Clinical Evolution
- 2014
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 74:16, s. 4211-4216
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Forskningsöversikt (refereegranskat)abstract
- Over the last decade, immunogenetic analysis of B-cell receptor immunoglobulins (BcR IG) has proved instrumental in dissecting chronic lymphocytic leukemia (CLL) pathogenesis. Initially, it was the finding that the level of somatic hypermutations in rearranged IG heavy-chain genes could define two CLL subtypes associated with a different clinical course that drew attention. As the years ensued, this not only continued to hold strong, but also revealed an unprecedented BcR restriction (aptly coined as "stereotypy"), thus cementing the idea that antigenic elements select the leukemic clones. With all this in mind, in the present review, we focus on the CLL BcR IG, a molecule that clearly lies at the heart of disease pathogenesis, and attempt to distil from past and emerging biologic knowledge the most relevant aspects in the context of the immunogenetics of CLL, while at the same time provoking questions that remain unanswered. We juxtapose CLL with mutated BcR IGs against CLL with unmutated BcR IGs due to their striking clinicobiologic differences; however, when considering ontogeny, common derivation of the two mutational subtypes cannot be excluded. The issue of stereotypy is intertwined throughout and we also raise the subject of isotype-switched CLL, which, despite its rarity, contributes intriguing ontogenetic hints.
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| 38. |
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| 39. |
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| 40. |
- Xochelli, Aliki, et al.
(författare)
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Chronic Lymphocytic Leukemia with Mutated IGHV4-34 Receptors : Shared and Distinct Immunogenetic Features and Clinical Outcomes
- 2017
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Ingår i: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 23:17, s. 5292-5301
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: We sought to investigate whether B cell receptor immunoglobulin (BcR IG) stereotypy is associated with particular clinicobiological features among chronic lymphocytic leukemia (CLL) patients expressing mutated BcR IG (M-CLL) encoded by the IGHV4-34 gene, and also ascertain whether these associations could refine prognostication. Experimental Design: In a series of 19,907 CLL cases with available immunogenetic information, we identified 339 IGHV4-34expressing cases assigned to one of the four largest stereotyped M-CLL subsets, namely subsets #4, #16, #29 and #201, and investigated in detail their clinicobiological characteristics and disease outcomes. Results: We identified shared and subset-specific patterns of somatic hypermutation (SHM) among patients assigned to these subsets. The greatest similarity was observed between subsets #4 and #16, both including IgG-switched cases (IgG-CLL). In contrast, the least similarity was detected between subsets #16 and #201, the latter concerning IgM/D-expressing CLL. Significant differences between subsets also involved disease stage at diagnosis and the presence of specific genomic aberrations. IgG subsets #4 and #16 emerged as particularly indolent with a significantly (P < 0.05) longer time-to-first-treatment (TTFT; median TTFT: not yet reached) compared with the IgM/D subsets #29 and #201 (median TTFT: 11 and 12 years, respectively). Conclusions: Our findings support the notion that BcR IG stereotypy further refines prognostication in CLL, superseding the immunogenetic distinction based solely on SHM load. In addition, the observed distinct genetic aberration landscapes and clinical heterogeneity suggest that not all M-CLL cases are equal, prompting further research into the underlying biological background with the ultimate aim of tailored patient management.
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| 41. |
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| 42. |
- Xochelli, Aliki, et al.
(författare)
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Disease-biased and shared characteristics of the immunoglobulin gene repertoires in marginal zone B cell lymphoproliferations
- 2019
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Ingår i: Journal of Pathology. - : WILEY. - 0022-3417 .- 1096-9896. ; 247:4, s. 416-421
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Tidskriftsartikel (refereegranskat)abstract
- The B cell receptor immunoglobulin (Ig) gene repertoires of marginal zone (MZ) lymphoproliferations were analyzed in order to obtain insight into their ontogenetic relationships. Our cohort included cases with MZ lymphomas (n = 488), i.e. splenic (SMZL), nodal (NMZL) and extranodal (ENMZL), as well as provisional entities (n = 76), according to the WHO classification. The most striking Ig gene repertoire skewing was observed in SMZL. However, restrictions were also identified in all other MZ lymphomas studied, particularly ENMZL, with significantly different Ig gene distributions depending on the primary site of involvement. Cross-entity comparisons of the MZ Ig sequence dataset with a large dataset of Ig sequences (MZ-related or not; n = 65 837) revealed four major clusters of cases sharing homologous ('public') heavy variable complementarity-determining region 3. These clusters included rearrangements from SMZL, ENMZL (gastric, salivary gland, ocular adnexa), chronic lymphocytic leukemia, but also rheumatoid factors and non-malignant splenic MZ cells. In conclusion, different MZ lymphomas display biased immunogenetic signatures indicating distinct antigen exposure histories. The existence of rare public stereotypes raises the intriguing possibility that common, pathogen-triggered, immune-mediated mechanisms may result in diverse B lymphoproliferations due to targeting versatile progenitor B cells and/or operating in particular microenvironments.
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| 43. |
- Xochelli, Aliki, et al.
(författare)
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Immunoglobulin heavy variable (IGHV) genes and alleles : new entities, new names and implications for research and prognostication in chronic lymphocytic leukaemia
- 2015
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Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 67:1, s. 61-66
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Tidskriftsartikel (refereegranskat)abstract
- Ieext generation sequencing studies in Homo sapiens have identified novel immunoglobulin heavy variable (IGHV) genes and alleles necessitating changes in the international ImMunoGeneTics information system (IMGT) GENE-DB and reference directories of IMGT/V-QUEST. In chronic lymphocytic leukaemia (CLL), the somatic hypermutation (SHM) status of the clonotypic rearranged IGHV gene is strongly associated with patient outcome. Correct determination of this parameter strictly depends on the comparison of the nucleotide sequence of the clonotypic rearranged IGHV gene with that of the closest germline counterpart. Consequently, changes in the reference directories could, in principle, affect the correct interpretation of the IGHV mutational status in CLL. To this end, we analyzed 8066 productive IG heavy chain (IGH) rearrangement sequences from our consortium both before and after the latest update of the IMGT/V-QUEST reference directory. Differences were identified in 405 cases (5 % of the cohort). In 291/405 sequences (71.9 %), changes concerned only the IGHV gene or allele name, whereas a change in the percent germline identity (%GI) was noted in 114/405 (28.1 %) sequences; in 50/114 (43.8 %) sequences, changes in the %GI led to a change in the mutational set. In conclusion, recent changes in the IMGT reference directories affected the interpretation of SHM in a sizeable number of IGH rearrangement sequences from CLL patients. This indicates that both physicians and researchers should consider a re-evaluation of IG sequence data, especially for those IGH rearrangement sequences that, up to date, have a GI close to 98 %, where caution is warranted.
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| 44. |
- Xochelli, Aliki, et al.
(författare)
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Molecular Evidence for Antigen Drive in the Natural History of Mantle Cell Lymphoma
- 2015
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Ingår i: American Journal of Pathology. - : Elsevier BV. - 0002-9440 .- 1525-2191. ; 185:6, s. 1740-1748
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Tidskriftsartikel (refereegranskat)abstract
- To further our understanding about antigen involvement in mantle cell Lymphoma (MCL), we analyzed the expression levels of activation-induced cytidine deaminase (AID), a key player in B-cell responses to antigen triggering, in 133 MCL cases; assessed the functionality of AID by evaluating in vivo class switch recombination in 52 MCL cases; and sought for indications of ongoing antigen interactions by exploring intraclonal diversification within 14 MCL cases. The AID full-length transcript and the most frequent splice variants (AID-Delta E4a, AID-Delta E) were detected in 128 (96.2%), 96 (72.2%), and 130 cases (97.7%), respectively. Higher AID full-Length transcript levels were significantly associated (P < 0.001) with Lack of somatic hypermutation within the clonotypic immunoglobulin heavy variable (IGHV) genes. Median AID transcript levels were higher in lymph node material compared to cases in which peripheral blood was analyzed, implying that clonal behavior is influenced by the microenvironment. Switched tumor-derived IGHV-IGHD-IGHJ transcripts were identified in 5 of 52 cases (9.6%), all of which displayed somatic hypermutation and AID-mRNA expression. Finally, although most cases exhibited low levels of intraclonal diversification, analysis of the mutational activity revealed a precise targeting of somatic hypermutation indicative of an active, ongoing interaction with antigen(s). Collectively, these findings strongly allude to antigen involvement in the natural history of MCL, further challenging the notion of antigen naivety.
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| 45. |
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