1
|
Quinten E, Sepúlveda-Yáñez JH, Koning MT, Eken JA, Pfeifer D, Nteleah V, De Groen RAL, Saravia DA, Knijnenburg J, Stuivenberg-Bleijswijk HE, Pantic M, Agathangelidis A, Keppler-Hafkemeyer A, Van Bergen CAM, Uribe-Paredes R, Stamatopoulos K, Vermaat JSP, Zirlik K, Navarrete MA, Jumaa H, Veelken H. Autonomous B-cell receptor signaling and genetic aberrations in chronic lymphocytic leukemia-phenotype monoclonal B lymphocytosis in siblings of patients with chronic lymphocytic leukemia. Haematologica 2024; 109:824-834. [PMID: 37439337 PMCID: PMC10905078 DOI: 10.3324/haematol.2022.282542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023] Open
Abstract
Clonal expansion of CD5-expressing B cells, commonly designated as monoclonal B lymphocytosis (MBL), is a precursor condition for chronic lymphocytic leukemia (CLL). The mechanisms driving subclinical MBL B-cell expansion and progression to CLL, occurring in approximately 1% of affected individuals, are unknown. An autonomously signaling B-cell receptor (BCR) is essential for the pathogenesis of CLL. The objectives of this study were functional characterization of the BCR of MBL in siblings of CLL patients and a comparison of genetic variants in MBL-CLL sibling pairs. Screening of peripheral blood by flow cytometry detected 0.2-480 clonal CLL-phenotype cells per microliter (median: 37/μL) in 34 of 191 (17.8%) siblings of CLL patients. Clonal BCR isolated from highly purified CLL-phenotype cells induced robust calcium mobilization in BCR-deficient murine pre-B cells in the absence of external antigen and without experimental crosslinking. This autonomous BCR signal was less intense than the signal originating from the CLL BCR of their CLL siblings. According to genotyping by single nucleotide polymorphism array, whole exome, and targeted panel sequencing, CLL risk alleles were found with high and similar prevalence in CLL patients and MBL siblings, respectively. Likewise, the prevalence of recurrent CLL-associated genetic variants was similar between CLL and matched MBL samples. However, copy number variations and small variants were frequently subclonal in MBL cells, suggesting their acquisition during subclinical clonal expansion. These findings support a stepwise model of CLL pathogenesis, in which autonomous BCR signaling leads to a non-malignant (oligo)clonal expansion of CD5+ B cells, followed by malignant progression to CLL after acquisition of pathogenic genetic variants.
Collapse
Affiliation(s)
- Edwin Quinten
- Department of Hematology, Leiden University Medical Center, Leiden
| | - Julieta H Sepúlveda-Yáñez
- Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands; School of Medicine, Universidad de Magallanes, Punta Arenas, Chile
| | - Marvyn T Koning
- Department of Hematology, Leiden University Medical Center, Leiden
| | - Janneke A Eken
- Department of Hematology, Leiden University Medical Center, Leiden
| | - Dietmar Pfeifer
- Department of Medicine I, University Medical Center Freiburg, Freiburg
| | - Valeri Nteleah
- Department of Hematology, Leiden University Medical Center, Leiden
| | | | | | - Jeroen Knijnenburg
- Department of Clinical Genetics, Leiden University Medical Center, Leiden
| | | | - Milena Pantic
- Department of Medicine I, University Medical Center Freiburg, Freiburg
| | - Andreas Agathangelidis
- Department of Biology, School of Science, National and Kapodistrian University of Athens, Athens, Greece; Institute of Applied Biosciences, Centre for Research and Technology Hellas, Thessaloniki, Greece
| | | | | | - Roberto Uribe-Paredes
- Department of Computer Engineering, Universidad de Magallanes, Punta Arenas, Chile; Centre for Biotechnology and Bioengineering, Santiago, Chile
| | - Kostas Stamatopoulos
- Institute of Applied Biosciences, Centre for Research and Technology Hellas, Thessaloniki, Greece; Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm
| | | | - Katja Zirlik
- Department of Medicine I, University Medical Center Freiburg, Freiburg, Germany; Tumor-und Brustzentrum Ostschweiz, Chur
| | | | | | - Hendrik Veelken
- Department of Hematology, Leiden University Medical Center, Leiden.
| |
Collapse
|
2
|
Semenzato G, Ghobrial IM, Ghia P. Monoclonal B-cell lymphocytosis, monoclonal gammopathy of undetermined significance, and T-cell clones of uncertain significance: are these premalignant conditions sharing a common identity? Lancet Haematol 2023; 10:e549-e556. [PMID: 37407144 DOI: 10.1016/s2352-3026(23)00086-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 07/07/2023]
Abstract
Monoclonal B-cell lymphocytosis, monoclonal gammopathy of undetermined significance, and T-cell clones of uncertain significance are three premalignant conditions characterised by the presence of small clonal cell expansions in individuals without symptoms or signs that distinguish the related overt malignancies (chronic lymphocytic leukaemia, multiple myeloma, and T-cell large granular lymphocytic leukaemia). As most individuals with these precursor states never progress to malignancies, considerable interest has arisen in comprehending the steps involved in the progression to malignancy, providing more accurate models to investigate potential mechanisms of early blood cancer identification, prevention, and, possibly, intervention. Single-cell technologies and recent progress in high-throughput sequencing and multiomics approaches have contributed to a better definition of the pathophysiological mechanisms of these premalignant conditions, moving our knowledge in the field forward. In this Viewpoint, we analyse the seemingly shared biological trajectories in these precursor haematological malignancies in search of common pathogenetic events. In particular, we address the issue of interactions between expanding clones and their immune ecosystem, offering new clues that might prompt innovative ideas and inspire further investigations to understand the cellular and molecular dynamics entailing progression into overt malignant disease. The relationships between the non-leukaemic microenvironmental cells and the leukaemic counterpart, and the primary drivers of their initial clonal expansion, represent shared biologies that suggest a common identity among the premalignant conditions considered in this Viewpoint.
Collapse
Affiliation(s)
- Gianpietro Semenzato
- Haematology Section, Department of Medicine, University of Padova, Padua, Italy; Veneto Institute of Molecular Medicine, Padua, Italy.
| | | | - Paolo Ghia
- Vita-Salute San Raffaele University, Milan, Italy; IRCCS San Raffaele Hospital, Milan, Italy
| |
Collapse
|
3
|
Tang C, Shen Y, Soosapilla A, Mulligan SP. Monoclonal B-cell Lymphocytosis - a review of diagnostic criteria, biology, natural history, and clinical management. Leuk Lymphoma 2022; 63:2795-2806. [PMID: 35767361 DOI: 10.1080/10428194.2022.2092857] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Since first described almost two decades ago, there has been significant evolution in our definition and understanding of the biology and implications of monoclonal B-cell lymphocytosis (MBL). This review provides an overview of the definition, classification, biology, and natural history of MBL, mainly focused on the dominant CLL-like phenotype form of MBL. The increasingly recognized implications of MBL with respect to immune dysfunction are discussed, particularly in view of the COVID-19 pandemic, along with management recommendations for MBL in the clinic.
Collapse
Affiliation(s)
- Catherine Tang
- Department of Haematology and Flow Cytometry, Laverty Pathology, Sydney, Australia.,Department of Haematology, Gosford Hospital, Gosford, Australia.,School of Medicine and Public Health, The University of Newcastle, Newcastle, Australia
| | - Yandong Shen
- Department of Haematology, Royal North Shore Hospital, St Leonards, Sydney, Australia.,Kolling Institute, University of Sydney, St Leonards, Sydney, Australia
| | - Asha Soosapilla
- Department of Haematology and Flow Cytometry, Laverty Pathology, Sydney, Australia
| | - Stephen P Mulligan
- Department of Haematology and Flow Cytometry, Laverty Pathology, Sydney, Australia.,Department of Haematology, Royal North Shore Hospital, St Leonards, Sydney, Australia.,Kolling Institute, University of Sydney, St Leonards, Sydney, Australia
| |
Collapse
|
4
|
Bagnara D, Colombo M, Reverberi D, Matis S, Massara R, Cardente N, Ubezio G, Agostini V, Agnelli L, Neri A, Cardillo M, Vergani S, Ghiotto F, Mazzarello AN, Morabito F, Cutrona G, Ferrarini M, Fais F. Characterizing Features of Human Circulating B Cells Carrying CLL-Like Stereotyped Immunoglobulin Rearrangements. Front Oncol 2022; 12:894419. [PMID: 35837088 PMCID: PMC9275393 DOI: 10.3389/fonc.2022.894419] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Chronic Lymphocytic Leukemia (CLL) is characterized by the accumulation of monoclonal CD5+ B cells with low surface immunoglobulins (IG). About 40% of CLL clones utilize quasi-identical B cell receptors, defined as stereotyped BCR. CLL-like stereotyped-IG rearrangements are present in normal B cells as a part of the public IG repertoire. In this study, we collected details on the representation and features of CLL-like stereotyped-IG in the IGH repertoire of B-cell subpopulations purified from the peripheral blood of nine healthy donors. The B-cell subpopulations were also fractioned according to the expression of surface CD5 molecules and IG light chain, IGκ and IGλ. IG rearrangements, obtained by high throughput sequencing, were scanned for the presence of CLL-like stereotyped-IG. CLL-like stereotyped-IG did not accumulate preferentially in the CD5+ B cells, nor in specific B-cell subpopulations or the CD5+ cell fraction thereof, and their distribution was not restricted to a single IG light chain type. CLL-like stereotyped-IG shared with the corresponding CLL stereotype rearrangements the IGHV mutational status. Instead, for other features such as IGHV genes and frequency, CLL stereotyped-IGs presented a CLL-like subset specific behavior which could, or could not, be consistent with CLL stereotyped-IGs. Therefore, as opposed to the immuno-phenotype, the features of the CLL stereotyped-IG repertoire suggest a CLL stereotyped subset-specific ontogeny. Overall, these findings suggest that the immune-genotype can provide essential details in tracking and defining the CLL cell of origin.
Collapse
Affiliation(s)
- Davide Bagnara
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
- *Correspondence: Davide Bagnara,
| | - Monica Colombo
- Molecular Pathology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Daniele Reverberi
- Molecular Pathology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Serena Matis
- Molecular Pathology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Rosanna Massara
- Molecular Pathology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Niccolò Cardente
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Gianluca Ubezio
- Transfusion Centre, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Vanessa Agostini
- Transfusion Centre, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Luca Agnelli
- Department of Pathology, IRCCS Istituto Nazionale dei Tumori, Milan, Italy
- Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy
| | - Antonino Neri
- Scientific Directorate, Azienza Unità Sanitaria Locale (USL)-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Martina Cardillo
- Karches Center for Oncology Research, The Feinstein Institute for Medical Research, Manhasset, NY, United States
| | - Stefano Vergani
- Developmental Immunology Unit, Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Fabio Ghiotto
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
- Molecular Pathology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | | | - Fortunato Morabito
- Hematology and Bone Marrow Transplant Unit, Hemato-Oncology Department, Augusta Victoria Hospital, East Jerusalem, Israel
- Biothecnology Research Unit, AO of Cosenza, Cosenza, Italy
| | - Giovanna Cutrona
- Molecular Pathology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Manlio Ferrarini
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Franco Fais
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
- Molecular Pathology, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| |
Collapse
|
5
|
Kolijn PM, Hosnijeh FS, Späth F, Hengeveld PJ, Agathangelidis A, Saleh M, Casabonne D, Benavente Y, Jerkeman M, Agudo A, Barricarte A, Besson C, Sánchez MJ, Chirlaque MD, Masala G, Sacerdote C, Grioni S, Schulze MB, Nieters A, Engelfriet P, Hultdin M, McKay JD, Vermeulen RC, Langerak AW. High-risk subtypes of chronic lymphocytic leukemia are detectable as early as 16 years prior to diagnosis. Blood 2022; 139:1557-1563. [PMID: 34662377 PMCID: PMC10650964 DOI: 10.1182/blood.2021012890] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 10/04/2021] [Indexed: 11/20/2022] Open
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.
Collapse
Affiliation(s)
- P. Martijn Kolijn
- Department of Immunology, Laboratory Medical Immunology, Erasmus MC, Rotterdam, The Netherlands
- Division of Environmental Epidemiology and Veterinary Public Health, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Fatemeh Saberi Hosnijeh
- Division of Environmental Epidemiology and Veterinary Public Health, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Florentin Späth
- Department of Radiation Sciences, Oncology, Cancer Center, Department of Hematology
| | - Paul J. Hengeveld
- Department of Immunology, Laboratory Medical Immunology, Erasmus MC, Rotterdam, The Netherlands
| | - Andreas Agathangelidis
- Institute of Applied Biosciences, Centre for Research and Technology Hellas, Thessaloniki, Greece
- Department of Biology, School of Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Manal Saleh
- Division of Environmental Epidemiology and Veterinary Public Health, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Delphine Casabonne
- Centro de Investigación Biomédica en Red: Epidemiología y Salud Pública, Madrid, Spain
- Unit of Molecular and Genetic Epidemiology in Infections and Cancer, Cancer Epidemiology Research Programme, Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, Hospitalet De Llobregat, Barcelona, Spain
| | - Yolanda Benavente
- Centro de Investigación Biomédica en Red: Epidemiología y Salud Pública, Madrid, Spain
- Unit of Molecular and Genetic Epidemiology in Infections and Cancer, Cancer Epidemiology Research Programme, Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, Hospitalet De Llobregat, Barcelona, Spain
| | - Mats Jerkeman
- Division of Oncology, Lund University, Lund, Sweden
- Department of Oncology, Skane University Hospital, Lund, Sweden
| | - Antonio Agudo
- Unit of Nutrition and Cancer, Epidemiology, Public Health, Cancer Prevention, and Palliative Care Program, Bellvitge Biomedical Research Institute, Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, Hospitalet De Llobregat, Barcelona, Spain
| | - Aurelio Barricarte
- Navarra Public Health Institute, Navarra Institute for Health Research, Pamplona, Spain
- Biomedical Research Networking Center for Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Caroline Besson
- Université Paris-Saclay, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), French Institute of Health and Medical Research (INSERM), Équipe “Exposome et Hérédité”, Centre de Recherche en épidémiologie et Santé des populations (CESP), Villejuif, France
- Service d'Hématologie Oncologie, Centre Hospitalier de Versailles, Le Chesnay, France
| | - Maria-Jose Sánchez
- Escuela Andaluza de Salud Pública, Instituto de Investigación Biosanitaria ibs.GRANADA, Department of Preventive Medicine and Public Health, University of Granada, Granada, Spain
- Centro de Investigación Biomédica en Red: Epidemiología y Salud Pública, Madrid, Spain
| | - María-Dolores Chirlaque
- Biomedical Research Networking Center for Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Department of Epidemiology, Regional Health Council, Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Arrixaca), Murcia University, Murcia, Spain
| | - Giovanna Masala
- Epidemiology Unit, Institute for Cancer Research, Prevention and Clinical Network, Florence, Italy
| | - Carlotta Sacerdote
- Unit of Cancer Epidemiology, Città della Salute e della Scienza University-Hospital, Turin, Italy
| | - Sara Grioni
- Epidemiology and Prevention Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Nazionale dei Tumori di Milano, Milano, Italy
| | - Matthias B. Schulze
- Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
- Institute of Nutritional Science, University of Potsdam, Potsdam, Germany
| | - Alexandra Nieters
- Institute for Immunodeficiency, University Medical Center Freiburg, Freiburg, Germany
| | - Peter Engelfriet
- National Institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Magnus Hultdin
- Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden
| | - James D. McKay
- Genomic Epidemiology Branch, International Agency for Research on Cancer, Lyon, France
| | - Roel C.H. Vermeulen
- Division of Environmental Epidemiology and Veterinary Public Health, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Anton W. Langerak
- Department of Immunology, Laboratory Medical Immunology, Erasmus MC, Rotterdam, The Netherlands
| |
Collapse
|
6
|
Galigalidou C, Zaragoza-Infante L, Iatrou A, Chatzidimitriou A, Stamatopoulos K, Agathangelidis A. Understanding Monoclonal B Cell Lymphocytosis: An Interplay of Genetic and Microenvironmental Factors. Front Oncol 2021; 11:769612. [PMID: 34858849 PMCID: PMC8631769 DOI: 10.3389/fonc.2021.769612] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/26/2021] [Indexed: 11/13/2022] Open
Abstract
The term monoclonal B-cell lymphocytosis (MBL) describes the presence of a clonal B cell population with a count of less than 5 × 109/L and no symptoms or signs of disease. Based on the B cell count, MBL is further classified into 2 distinct subtypes: 'low-count' and 'high-count' MBL. High-count MBL shares a series of biological and clinical features with chronic lymphocytic leukemia (CLL), at least of the indolent type, and evolves to CLL requiring treatment at a rate of 1-2% per year, whereas 'low-count' MBL seems to be distinct, likely representing an immunological rather than a pre-malignant condition. That notwithstanding, both subtypes of MBL can carry 'CLL-specific' genomic aberrations such as cytogenetic abnormalities and gene mutations, yet to a much lesser extent compared to CLL. These findings suggest that such aberrations are mostly relevant for disease progression rather than disease onset, indirectly pointing to microenvironmental drive as a key contributor to the emergence of MBL. Understanding microenvironmental interactions is therefore anticipated to elucidate MBL ontogeny and, most importantly, the relationship between MBL and CLL.
Collapse
Affiliation(s)
- Chrysi Galigalidou
- Institute of Applied Biosciences (INAB), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece.,Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - Laura Zaragoza-Infante
- Institute of Applied Biosciences (INAB), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece.,Hematology Department, University General Hospital of Thessaloniki AHEPA, Thessaloniki, Greece
| | - Anastasia Iatrou
- Institute of Applied Biosciences (INAB), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece
| | - Anastasia Chatzidimitriou
- Institute of Applied Biosciences (INAB), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Kostas Stamatopoulos
- Institute of Applied Biosciences (INAB), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Andreas Agathangelidis
- Institute of Applied Biosciences (INAB), Centre for Research and Technology Hellas (CERTH), Thessaloniki, Greece.,Department of Biology, School of Science, National and Kapodistrian University of Athens, Athens, Greece
| |
Collapse
|
7
|
Higher-order connections between stereotyped subsets: implications for improved patient classification in CLL. Blood 2021; 137:1365-1376. [PMID: 32992344 DOI: 10.1182/blood.2020007039] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/04/2020] [Indexed: 12/20/2022] Open
Abstract
Chronic lymphocytic leukemia (CLL) is characterized by the existence of subsets of patients with (quasi)identical, stereotyped B-cell receptor (BcR) immunoglobulins. Patients in certain major stereotyped subsets often display remarkably consistent clinicobiological profiles, suggesting that the study of BcR immunoglobulin stereotypy in CLL has important implications for understanding disease pathophysiology and refining clinical decision-making. Nevertheless, several issues remain open, especially pertaining to the actual frequency of BcR immunoglobulin stereotypy and major subsets, as well as the existence of higher-order connections between individual subsets. To address these issues, we investigated clonotypic IGHV-IGHD-IGHJ gene rearrangements in a series of 29 856 patients with CLL, by far the largest series worldwide. We report that the stereotyped fraction of CLL peaks at 41% of the entire cohort and that all 19 previously identified major subsets retained their relative size and ranking, while 10 new ones emerged; overall, major stereotyped subsets had a cumulative frequency of 13.5%. Higher-level relationships were evident between subsets, particularly for major stereotyped subsets with unmutated IGHV genes (U-CLL), for which close relations with other subsets, termed "satellites," were identified. Satellite subsets accounted for 3% of the entire cohort. These results confirm our previous notion that major subsets can be robustly identified and are consistent in relative size, hence representing distinct disease variants amenable to compartmentalized research with the potential of overcoming the pronounced heterogeneity of CLL. Furthermore, the existence of satellite subsets reveals a novel aspect of repertoire restriction with implications for refined molecular classification of CLL.
Collapse
|