Subjects with chronic lymphocytic leukaemia-like B-cell clones with stereotyped B-cell receptors frequently show MDS-associated phenotypes on myeloid cells

An increasing body of evidence suggests the potential occurrence of antigen encounter by the cell of origin in chronic lymphocytic leukaemia (CLL) and CLL-like monoclonal B-cell lymphocytosis (MBL). However, the scenario in which this event might occur remains unknown. In order to gain insight into this scenario we investigated the molecular, cytogenetic and haematological features of 223 CLL-like (n = 84) and CLL (n = 139) clones with stereotyped (n = 32) versus non-stereotyped (n = 191) immunoglobulin heavy chain variable region (IGHV) amino acid sequences. Overall, stereotyped CLL-like MBL and CLL clones showed a unique IGHV profile, associated with higher IGHV1 and lower IGHV3 gene family usage (P = 0·03), longer IGHV complementary determining region 3 (HCDR3) sequences (P = 0·007) and unmutated IGHV (P 0·05), it did show a significant association with the presence of myelodysplastic syndrome (MDS)-associated immunophenotypes on peripheral blood neutrophils and/or monocytes (P = 0·01). Altogether our results point to the potential involvement of different selection forces in the expansion of stereotyped vs. non-stereotyped CLL and CLL-like MBL clones, the former being potentially favoured by an underlying altered haematopoiesis.Funded by: Red Temática de Investigación Cooperativa en Cáncer (RTICC) of Instituto de Salud Carlos III – FONDOS FEDER. Grant Numbers: RD06/0020/0035, RD12/0036/0048, FIS PI06/0824-FEDER, PS09/02430-FEDER; FIS PI12/00905-FEDER Fondo de Investigación Sanitaria of Instituto de Salud Carlos III. Grant Numbers: GRS206/A/08, SAN/1778/2009; Gerencia Regional de Salud, Consejería de Educación and Consejería de Sanidad of Castilla y León. Grant Numbers: FS/1-2010, FS/19-2013; Fundación Memoria D. Samuel Solórzano, Universidad de Salamanca; Fundação para a Ciência e Tecnologia of Portugal. Grant Number: SFRH/BD/31609/2006; Fundación Científica de la Asociación Española contra el Cáncer. Grant Number: AECC-2008.Peer Reviewe