Hospital population screening reveals overrepresentation of CD5− monoclonal B-cell lymphocytosis and monoclonal gammopathy of undetermined significance of IgM type

Monoclonal B-cell Lymphocytosis Exacerbated by Prednisolone Therapy for Dermatomyositis

Lymphoproliferative diseases have been associated with various autoimmune diseases. We experienced a case of non-chronic lymphocytic leukemia type monoclonal B-cell lymphocytosis (MBL) that was exacerbated by increasing prednisolone for dermatomyositis and then improved by decreasing the dosage. Because MBL is difficult to diagnose, cases like ours may not be rare. These findings will facilitate our understanding of the mechanism underlying lymphoproliferative diseases and autoimmune diseases.

Targeting the Mutational Landscape of Bystander Cells: Drug-Promoted Blood Cancer From High-Prevalence Pre-neoplasias in Patients on BRAF Inhibitors

Drug-promoted cancers are increasingly recognized as a serious clinical problem in patients receiving BRAF inhibitory treatment. Here we report on a patient with BRAF mutant hairy cell leukemia and monoclonal B-cell lymphocytosis (MBL), who responded durably to BRAF/MEK inhibitors (BRAFi/MEKi) but experienced transformation of a RAS mutant MBL to chronic lymphocytic leukemia (CLL) with accelerated nodal progression. Hypothesizing that BRAFi triggered excessive MEK-ERK signaling in the MBL/CLL clone via the CRAF/RAS complex as previously described for BRAFi-induced cancers, BRAFi was discontinued inducing a rapid remission of the CLL on MEKi alone. Liquid biopsy monitoring showed a continuous increase of the MBL/CLL clone from the start of BRAFi/MEKi treatment followed by a rapid decline upon BRAFi withdrawal. Next-generation sequencing of a cohort of patients with MBL and monoclonal gammopathy of unclear significance (MGUS) revealed that almost one third of these cases harbored RAS mutations. In view of the population frequency of lymphatic pre-malignant conditions and the prevalence of RAS mutations in such cases, vigilant surveillance remains critical in patients treated with BRAF inhibitors.

Screening for monoclonal B-lymphocyte expansion in a hospital-based Chinese population with lymphocytosis: an observational cohort study

OBJECTIVES

Screening of monoclonal B-cell lymphocytosis (MBL) has improved the early detection of B-cell lymphoproliferative disorders (B-LPDs). This study was designed to find the most cost-effective way to screen for asymptomatic B-LPD.

DESIGN

Observational study.

SETTING

A lymphocytosis screening project was conducted at a large-scale hospital among the Chinese population.

PARTICIPANTS

For 10 consecutive working days in 2018, 22 809 adult patients who received a complete blood count (CBC) were reviewed. These patients were selected from the outpatient, inpatient and health examination departments of a National Medical Centre in China.

RESULTS

A total of 254 patients (1.1%, 254/22 809) were found to have lymphocytosis (absolute lymphocyte count (ALC) >3.5×10⁹/L). Among them, a population of circulating monoclonal B-lymphocytes were detected in 14 patients, with 4 having chronic lymphocytic leukaemia (CLL) and 10 having MBL, indicating an overall prevalence of 5.5% for B-LPD (3.9% for MBL). The prevalence of CLL among the elderly patients with lymphocytosis (≥60 years) was determined to be 4.3% (4/92). In the patients over 60 years of age, the prevalence of MBL was found to be 8.7%. CD5 (-) non-CLL-like MBL was observed to be the most common subtype (8, 80%), followed by CLL-like phenotype (1, 10.0%) and atypical CLL phenotype (1, 10.0%). The receiver operating characteristic curve analysis for the CBC results revealed that the ALC of 4.7×10⁹/L may serve as the optimal and cost-effective cut-off for screening for early-stage asymptomatic B-LPD.

CONCLUSION

In Chinese patients with lymphocytosis, there was a relatively high proportion of patients with CLL among individuals over 60 years of age. MBL is an age-related disorder. Non-CLL-like MBL was the most common MBL subtype, almost all of whom displayed a pattern of 'marginal zone lymphoma (MZL)-like' MBL. Lymphocytosis screening among the elderly would be effective in the detection of B-LPD and MBL.

Immunophenotypic profile and clinical outcome of monoclonal B-cell lymphocytosis in kidney transplantation

Monoclonal B-cell lymphocytosis (MBL) is a lymphoproliferative disorder characterized by clonal expansion of a B-cell population in peripheral blood of otherwise healthy subjects. MBL is divided into CLL (chronic lymphocytic leukemia)-like, atypical CLL-like and non-CLL MBL. The aim of this study was to evaluate immunophenotypic characteristics and clinical outcomes of MBL in kidney transplant (KT) recipients. We retrospectively evaluated 593 kidney transplant (KT) recipients in follow-up at our center. Among them, 157 patients underwent peripheral blood flow cytometry for different clinical indications. A 6-color panel flow cytometry was used to diagnose MBL. This condition was detected in 5 of 157 KT recipients. Immunophenotypic characterization of MBL showed four cases of non-CLL MBL and one case of CLL-like MBL. At presentation, median age was 65 years (range 61-73). After a median follow-up of 3.1 years (95%CI; 1.1-5) from diagnosis, patients did not progress either to CLL or to lymphoma. The disorder did not increase the risk of malignancy, severe infections, graft loss and mortality among our KT recipients. Surprisingly, all cases were also affected by concomitant monoclonal gammopathy of undetermined significance, which did not progress to multiple myeloma during follow-up. In conclusion, our data suggest that MBL is an age-related disorder, with non-CLL MBL being the most common subtype among KT recipients.

Monoclonal gammopathies regardless of subtypes are associated with poor prognosis of diffuse large B-cell lymphoma: A STROBE-compliant article

Monoclonal gammopathy (MG), a positive result of serum immunofixation electrophoresis (SIFE), has been reported in cases of diffuse large B-cell lymphoma (DLBCL). We performed this study to further investigate the prognostic value of MG in DLBCL.We retrospectively reviewed patients diagnosed with DLBCL between January 2007 and December 2014, and identified 37 patients with MG. The clinical characteristics of these patients were then reviewed. A 1:2 case-control analysis was conducted on 74 matched controls, who were patients with DLBCL and without MG. Both cases and controls were age-matched and were diagnosed within the same year.Among 37 DLBCL patients with MG, the monoclonal component of IgM was the most frequent compared to the other subtypes. Laboratory tests showed that the presence of MG was correlated with a decreased platelet-to-lymphocyte ratio (PLR). Survival analysis showed that MG-secreting DLBCL patients had an inferior overall survival (OS) and progression-free survival (PFS), compared with MG-nonsecreting patients, regardless of MG subtype. However, treatment response analysis showed that MG was not a good indicator for tumor relapse. When patients with DLBCL were grouped by immunophenotype, we found that MG was associated with poor prognosis in the non-germinal center B-cell-like (GCB) type, rather than GCB type in OS analysis. Meanwhile, there was no statistical significance upon PFS analysis in both immunophenotypes. Furthermore, our study found that the appearance of MG during treatment did make prognostic sense compared to nonsecretors.Overall, MG can serve as a prognostic factor for DLBCL. We hypothesize that its presence in DLBCL may reflect the immune microenvironment in tumor progression and warrants further study to unveil the underlying molecular pathogenesis.

Lymphoma-like monoclonal B cell lymphocytosis in a patient population: biology, natural evolution, and differences from CLL-like clones

High-count monoclonal B cell lymphocytosis (MBL) with a chronic lymphocytic leukemia (CLL) phenotype is a well-known entity, featuring 1-4% annual risk of progression towards CLL requiring treatment. Lymphoma-like MBL (L-MBL), on the other hand, remains poorly defined and data regarding outcome are lacking. We retrospectively evaluated 33 L-MBL cases within our hospital population and compared them to 95 subjects with CLL-like MBL (C-MBL). Diagnoses of L-MBL were based on asymptomatic B cell clones with Matutes score < 3, B cells < 5.0 × 10³/μl, and negative computerized tomography scans. We found that median B cell counts were considerably lower compared to C-MBL (0.6 vs 2.3 × 10³/μl) and remained stable over time. Based on immunophenotyping and immunogenetic profiling, most L-MBL clones did not correspond to known lymphoma entities. A strikingly high occurrence of paraproteinemia (48%), hypogammaglobulinemia (45%), and biclonality (21%) was seen; these incidences being significantly higher than in C-MBL (17, 21, and 5%, respectively). Unrelated monoclonal gammopathy of undetermined significance was a frequent feature, as the light chain type of 5/12 paraproteins detected was different from the clonal surface immunoglobulin. After 46-month median follow-up, 2/24 patients (8%) had progressed towards indolent lymphoma requiring no treatment. In contrast, 41% of C-MBL cases evolved to CLL and 17% required treatment. We conclude that clinical L-MBL is characterized by pronounced immune dysregulation and very slow or absent progression, clearly separating it from its CLL-like counterpart.