New Insights into Monoclonal B-Cell Lymphocytosis

Christina Kalpadakis,Stavroula Kyriakaki,Gerassimos A Pangalis,Penelope Korkolopoulou,Georgia Levidou,Xanthi Yiakoumis,Sotirios Sachanas,Pantelis Tsirkinidis,Marie-Christine Kyrtsonis,Panayiotis Panayiotidis,Helen A Papadaki,Theodoros P Vassilakopoulos,Maria Moschogiannis,Maria K Angelopoulou,Efstathios Koulieris

doi:10.1155/2014/258917

Abstract

Monoclonal B-cell lymphocytosis (MBL) is a premalignant condition characterized by the presence of less than 5000/μL circulating clonal B cells in otherwise healthy individuals. Three subcategories have been identified according to the immunophenotypic features: CLL-like, CD5(+) atypical, and CD5(−) MBL. CLL-like MBL is by far the most frequent and best studied category and further divided in low-count [LC] and high-count [HC] MBL, based on a cutoff value of 500/μL clonal B cells. LC-MBL typically remains stable and probably does not represent a truly premalignant condition, but rather an age-related immune senescence. On the other hand, HC-MBL is closely related to CLL-Rai0, bearing similar immunogenetic profile, and is associated with an annual risk of progression to CLL requiring therapy at a rate of 1.1%. Currently there are no reproducible factors for evaluating the risk of progression to CLL. CD5(−) MBL is characterized by an immunophenotype consistent with marginal zone origin and displays many similarities with marginal zone lymphomas (MZL), mainly the splenic MZL. The cutoff value of 5000/μL clonal B cells cannot probably be applied in CD5(−) MBL, requiring a new definition to describe those cases.

Highlights

Multiparameter flow cytometry analysis dramatically increased the sensitivity for detection of small B-cell clones in otherwise healthy individuals [1,2,3,4,5,6,7]
Monoclonal B-cell lymphocytosis (MBL) is a premalignant condition characterized by the presence of less than 5000/μL circulating clonal B cells in otherwise healthy individuals
CD5(−) MBL is characterized by an immunophenotype consistent with marginal zone origin and displays many similarities with marginal zone lymphomas (MZL), mainly the splenic MZL

Summary

Introduction

Multiparameter flow cytometry analysis dramatically increased the sensitivity for detection of small B-cell clones in otherwise healthy individuals [1,2,3,4,5,6,7]. In 2005 the International Familial CLL consortium summarized the literature, proposed certain diagnostic criteria to define this entity, and established the term “monoclonal B-cell lymphocytosis” (MBL) [8]. MBL is characterized by an asymptomatic monoclonal expansion of

CLL-Like MBL

Establishment of Reproducible Prognostic Factors

Findings

Commentary on CLL-Like MBL