Why Do We Diagnose Monoclonal B-cell Lymphocytosis? Five Questions.
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ABSTRACT:
SUBMITTER: Hibbs S
PROVIDER: S-EPMC10256376 | biostudies-literature | 2023 Jun
REPOSITORIES: biostudies-literature
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Why Do We Diagnose Monoclonal B-cell Lymphocytosis? Five Questions.
Hibbs Stephen S van Blarikom Esca E
HemaSphere 20230518 6
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Project description:Monoclonal B-cell lymphocytosis (MBL) is a preclinical hematologic syndrome characterized by small accumulations of CD5(+) B lymphocytes. Most MBL share phenotypic characteristics with chronic lymphocytic leukemia (CLL). Although some MBL progress to CLL, most MBL have apparently limited potential for progression to CLL, particularly those MBL with normal absolute B-cell counts ('low-count' MBL). Most CLL are monoclonal and it is not known whether MBL are monoclonal or oligoclonal; this is important because it is unclear whether MBL represent indolent CLL or represent a distinct premalignant precursor before the development of CLL. We used flow cytometry analysis and sorting to determine immunophenotypic characteristics, clonality and molecular features of MBL from familial CLL kindreds. Single-cell analysis indicated four of six low-count MBL consisted of two or more unrelated clones; the other two MBL were monoclonal. 87% of low-count MBL clones had mutated immunoglobulin genes, and no immunoglobulin heavy-chain rearrangements of V(H) family 1 were observed. Some MBL were diversified, clonally related populations with evidence of antigen drive. We conclude that although low-count MBL share many phenotypic characteristics with CLL, many MBL are oligoclonal. This supports a model for step-wise development of MBL into CLL.
| S-EPMC2806490 | biostudies-literature
Project description:MBL is a precursor condition to chronic lymphocytic leukemia (CLL), characterized by monoclonal B-cells in blood. Mosaic chromosomal alterations (mCAs) are a form of clonal hematopoiesis that include gains, losses, and copy-neutral loss-of-heterozygosity of large DNA segments. Both MBL and mCAs have been found to increase the risk of CLL and lymphoid malignancies, and the aim of our study was to investigate how mCAs relate to MBL, which is currently unknown. We analyzed genetic, flow cytometric, and hematologic data from 4632 individuals from the Mayo Clinic Biobank and CLL Database. MBL was detected using flow cytometry and classified as high-count (HC) or low-count (LC) MBL based on clone size. mCAs were detected primarily from whole blood DNA using sensitive SNP-array-based analyses. mCAs commonly altered in CLL (deletion of 6q, 11q, 13q, 17p, and trisomy 12) were specific (>99%) to individuals with MBL and CLL. HC-MBL and LC-MBL individuals were 881-fold and 8-fold, respectively, more likely to harbor CLL-associated mCAs than those without MBL. The cell fraction bearing these mCAs typically exceeded the B-cell fraction, suggesting their origin prior to the B-cell lineage. Integrating genetic and blood count data enabled detecting HC-MBL with high specificity in a biobank sample. These results quantify the contribution of mCAs to MBL and could enable large studies of HC-MBL without the need for flow cytometric screening.
| S-EPMC11541990 | biostudies-literature
Project description:Chronic lymphocytic lymphoma (CLL) has one of the highest familial risks among cancers. Monoclonal B-cell lymphocytosis (MBL), the precursor to CLL, has a higher prevalence (13%-18%) in families with 2 or more members with CLL compared with the general population (5%-12%). Although, the rate of progression to CLL for high-count MBLs (clonal B-cell count ≥500/µL) is ∼1% to 5%/y, no low-count MBLs have been reported to progress to date. We report the incidence and natural history of MBL in relatives from CLL families. In 310 CLL families, we screened 1045 relatives for MBL using highly sensitive flow cytometry and prospectively followed 449 of them. MBL incidence was directly age- and sex-adjusted to the 2010 US population. CLL cumulative incidence was estimated using Kaplan-Meier survival curves. At baseline, the prevalence of MBL was 22% (235/1045 relatives). After a median follow-up of 8.1 years among 449 relatives, 12 individuals progressed to CLL with a 5-year cumulative incidence of 1.8%. When considering just the 139 relatives with low-count MBL, the 5-year cumulative incidence increased to 5.7%. Finally, 264 had no MBL at baseline, of whom 60 individuals subsequently developed MBL (2 high-count and 58 low-count MBLs) with an age- and sex-adjusted incidence of 3.5% after a median of 6 years of follow-up. In a screening cohort of relatives from CLL families, we reported progression from normal-count to low-count MBL to high-count MBL to CLL, demonstrating that low-count MBL precedes progression to CLL. We estimated a 1.1% annual rate of progression from low-count MBL, which is in excess of that in the general population.
| S-EPMC8057266 | biostudies-literature
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| S-EPMC6286325 | biostudies-literature
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| S-EPMC9906370 | biostudies-literature
Project description:It is unknown whether individuals with monoclonal B-cell lymphocytosis (MBL) are at risk for adverse outcomes associated with chronic lymphocytic leukemia (CLL), such as the risk of non-hematologic cancer. We identified all locally residing individuals diagnosed with high-count MBL at Mayo Clinic between 1999 and 2009 and compared their rates of non-hematologic cancer with that of patients with CLL and two control cohorts: general medicine patients and patients who underwent clinical evaluation with flow cytometry but who had no hematologic malignancy. After excluding individuals with prior cancers, there were 107 high-count MBL cases, 132 CLL cases, 589 clinic controls and 482 flow cytometry controls. With 4.6 years median follow-up, 14 (13%) individuals with high-count MBL, 21 (4%) clinic controls (comparison MBL P<0.0001), 18 (4%) flow controls (comparison MBL P=0.0001) and 16 (12%) CLL patients (comparison MBL P=0.82) developed non-hematologic cancer. On multivariable Cox regression analysis, individuals with high-count MBL had higher risk of non-hematologic cancer compared with flow controls (hazard ratio (HR)=2.36; P=0.04) and borderline higher risk compared with clinic controls (HR=2.00; P=0.07). Patients with high-count MBL appear to be at increased risk for non-hematologic cancer, further reinforcing that high-count MBL has a distinct clinical phenotype despite low risk of progression to CLL.
| S-EPMC4839962 | biostudies-literature
Project description:Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic haematological condition characterized by low absolute levels of B-cell clones with a surface immunophenotype similar to that of chronic lymphocytic leukaemia (CLL). In the general population, MBL increases with age with a prevalence of 5-9% in individuals over age 60 years. It has been reported to be higher among first-degree relatives from CLL families. We report results of multi-parameter flow cytometry among 505 first-degree relatives with no personal history of lymphoproliferative disease from 140 families having at least two cases of CLL. Seventeen percent of relatives had MBL. Age was the most important determinant where the probability for developing MBL by age 90 years was 61%. MBL clustered in certain families but clustering was independent of the number of known CLL cases in a family. As is the case with CLL, males had a significantly higher risk for MBL than did females (P = 0·04). MBL patients had significantly higher mean absolute lymphocyte counts (2·4 × 10(9) /l) and B-cell counts (0·53 × 10(9) /l) than those with a normal B-cell immuno-phenotype. Our findings show that MBL occurs at a very high rate in high risk CLL families. Both the age and gender distribution of MBL are parallel to CLL, implying a shared inherited risk.
| S-EPMC2966536 | biostudies-literature
Project description:Families with multiple individuals affected with chronic lymphocytic leukemia (CLL) and other related B-cell tumors have been described in the literature. Familial CLL does not appear to differ from sporadic CLL in terms of prognostic markers and clinical outcome. While some environmental factors (such as farming related exposures and occupational chemicals) may increase risk of CLL, results of epidemiological studies have been generally inconsistent inconsistent and well-defined extrinsic risk factors are unknown. Large, population-based case-control and cohort studies have also shown significant familial aggregation of CLL and related conditions including non-Hodgkin lymphomas, especially other indolent lymphomas. The precursor condition, monoclonal B-cell lymphocytosis (MBL) also aggregates in CLL families. However because the baseline population risks for CLL and other indolent lymphomas are low, the absolute risk to a first-degree relative for developing CLL or a related disease is also low. Linkage studies have been conducted in high-risk CLL families to screen the whole genome for loci that contribute to susceptibility but no gene mutations have yet been identified by this method. Association studies of candidate genes have implicated several genes as being important in CLL but more studies are needed to verify these findings. Results from whole genome association are promising. The ability to conduct large scale genomic studies will play an important role in detecting susceptibility genes for CLL over the next few years and thereby help to delineate etiologic pathways.
| S-EPMC3010372 | biostudies-literature
Project description:Analysis of the T cell receptor (TR) repertoire of chronic lymphocytic leukemia-like monoclonal B cell lymphocytosis (CLL-like MBL) and early stage CLL is relevant for understanding the dynamic interaction of expanded B cell clones with bystander T cells. Here we profiled the T cell receptor β chain (TRB) repertoire of the CD4+ and CD8+ T cell fractions from 16 CLL-like MBL and 13 untreated, Binet stage A/Rai stage 0 CLL patients using subcloning analysis followed by Sanger sequencing. The T cell subpopulations of both MBL and early stage CLL harbored restricted TRB gene repertoire, with CD4+ T cell clonal expansions whose frequency followed the numerical increase of clonal B cells. Longitudinal analysis in MBL cases revealed clonal persistence, alluding to persistent antigen stimulation. In addition, the identification of shared clonotypes among different MBL/early stage CLL cases pointed towards selection of the T cell clones by common antigenic elements. T cell clonotypes previously described in viral infections and immune disorders were also detected. Altogether, our findings evidence that antigen-mediated TR restriction occurs early in clonal evolution leading to CLL and may further increase together with B cell clonal expansion, possibly suggesting that the T cell selecting antigens are tumor-related.
| S-EPMC5980379 | biostudies-literature
Project description:Autonomous BCR signaling and genetic aberrations in CLL-phenotype monoclonal B lymphocytosis in siblings of CLL patients
| PRJEB55176 | ENA