title: General population low-count CLL-like MBL persists over time without clinical progression, although carrying the same cytogenetic abnormalities of CLL.
abstract: Monoclonal B-cell lymphocytosis (MBL) is classified as chronic lymphocytic leukemia (CLL)-like, atypical CLL, and CD5(-) MBL. The number of B cells per microliter divides CLL-like MBL into MBL associated with lymphocytosis (usually detected in a clinical setting) and low-count MBL detected in the general population (usually identified during population screening). After a median follow-up of 34 months we reevaluated 76 low-count MBLs with 5-color flow cytometry: 90% of CLL-like MBL but only 44.4% atypical CLL and 66.7% CD5(-) MBL persisted over time. Population-screening CLL-like MBL had no relevant cell count change, and none developed an overt leukemia. In 50% of the cases FISH showed CLL-related chromosomal abnormalities, including monoallelic or biallelic 13q deletions (43.8%), trisomy 12 (1 case), and 17p deletions (2 cases). The analysis of the T-cell receptor β (TRBV) chains repertoire showed the presence of monoclonal T-cell clones, especially among CD4(high)CD8(low), CD8(high)CD4(low) T cells. TRBV2 and TRBV8 were the most frequently expressed genes. This study indicates that (1) the risk of progression into CLL for low-count population-screening CLL-like MBL is exceedingly rare and definitely lower than that of clinical MBL and (2) chromosomal abnormalities occur early in the natural history and are possibly associated with the appearance of the typical phenotype.
authors.affiliation: Laboratory of B cell Neoplasia, Division of Molecular Oncology, Istituto Scientifico San Raffaele, Via Olgettina 60, Milan, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Fazi
authors.forename: Lydia
authors.initials: L
authors.lastname: Scarfò
authors.forename: Lorenza
authors.initials: L
authors.lastname: Pecciarini
authors.forename: Francesca
authors.initials: F
authors.lastname: Cottini
authors.forename: Antonis
authors.initials: A
authors.lastname: Dagklis
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Janus
authors.forename: Anna
authors.initials: A
authors.lastname: Talarico
authors.forename: Cristina
authors.initials: C
authors.lastname: Scielzo
authors.forename: Cinzia
authors.initials: C
authors.lastname: Sala
authors.forename: Daniela
authors.initials: D
authors.lastname: Toniolo
authors.forename: Federico
authors.initials: F
authors.lastname: Caligaris-Cappio
authors.forename: Paolo
authors.initials: P
authors.lastname: Ghia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D002869:Chromosome Aberrations; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D018450:Disease Progression; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D018655:Lymphocyte Count; D008218:Lymphocytosis / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism / Q000473:pathology; D060152:V(D)J Recombination / Q000235:genetics
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta