Monoclonal B-cell lymphocytosis (MBL) with normal lymphocyte counts is associated with decreased numbers of normal circulating B-cell subsets

Primary Health Care Group of Salamanca for Study of MBL: et al.Monoclonal B-cell lymphocytosis (MBL) with normal lymphocyte counts is associated with decreased numbers of normal circulating B-cell subsets. Little is known about the distribution of normal lymphoid cells and their subsets in the peripheral blood (PB) of subjects with monoclonal Bcell lymphocytosis (MBL). In our study, we compared the absolute number of PB lymphoid cells and their subpopulations in 95 MBL cases with normal lymphocyte counts vs. 617 age-/sex-matched non-MBL healthy subjects (controls), using highly sensitive flow cytometry. MBL cases showed significantly reduced numbers of normal circulating B-cells, at the expense of immature and naïve B-cells; in addition, CD41CD81 double-positive T-cells and CD81 T-cells were significantly lower and higher vs. controls, respectively. Moreover, most normal B-cell subsets were significantly decreased in PB at ≥1% MBL-counts, vs. ''low-count'' MBL cases, and lower amounts of immature/naïve B-cells were detected in biclonal (particularly in cases with coexisting CLL-like- and non-CLL-like B-cell clones) vs. monoclonal MBL subjects. In summary, our results show imbalanced (reduced) absolute numbers of recently produced normal circulating B-cells (e.g., immature and naïve B-cells) in MBL, which becomes more pronounced as the MBL cell count increases. © 2012 Wiley Periodicals, Inc.Contract grant sponsor: Fonds zur Förderung der Wissenschaftlichen Forschung in Österreich (FWF), Austria; Contract grant number: J 2906-B13. Contract grant sponsor: Austrian Society of Hematology and Oncology; Grant numbers: RTICC RD06/0020/0035-FEDER, PI06/0824-FEDER and PS09/02430-FEDER. Contract grant sponsor: Fondo de Investigación Sanitaria, Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo, Madrid, Spain; Contract grant numbers: GRS206/A/08 and GREX-GR37. Contract grant sponsors: Gerencia Regional de Salud de Castilla y León and Ayuda al Grupo GR37 de Excelencia de Castilla y León, Consejería de Educación, Junta de Castilla y León, Valladolid, Spain; Contract grant number: SAN/1778/2009. Contract grant sponsor: Consejería de Sanidad, Junta de Castilla y León, Valladolid, Spain; Contract grant number: FS/ 16.2008. Contract grant sponsor: Fundación Samuel Solórzano, University of Salamanca, Salamanca, Spain, A.R-C. was supported by Fundación Científica de la Asociación Española contra el Cáncer.Peer ReviewedThe Primary Health Care Group of Salamanca for Study of MBL: et al