@article{Ignacio Criado_Arancha Rodríguez-Caballero_M. Laura Gutiérrez_Carlos E. Pedreira_Miguel Alcoceba_Wendy Nieto_Cristina Teodosio_Paloma Bárcena_Alfonso Romero_Paulino Fernández-Navarro_Marcos González_Julia Almeida_Alberto Orfao_The Primary Health Care Group of Salamanca for the Study of MBL_2018, place={Pavia, Italy}, title={Low-count monoclonal B-cell lymphocytosis persists after seven years of follow up and is associated with a poorer outcome}, volume={103}, url={https://haematologica.org/article/view/8524}, DOI={10.3324/haematol.2017.183954}, abstractNote={Low-count monoclonal B-cell lymphocytosis is defined by the presence of very low numbers of circulating clonal B cells, usually phenotypically similar to chronic lymphocytic leukemia cells, whose biological and clinical significance remains elusive. Herein, we re-evaluated 65/91 low-count monoclonal B-cell lymphocytosis cases (54 chronic lymphocytic leukemia-like and 11 non-chronic lymphocytic leukemia-like) followed-up for a median of seven years, using high-sensitivity flow cytometry and interphase fluorescence <em>in situ</em> hybridization. Overall, the clone size significantly increased in 69% of low-count monoclonal B-cell lymphocytosis cases, but only one subject progressed to high-count monoclonal B-cell lymphocytosis. In parallel, the frequency of cytogenetic alterations increased over time (32% <em>vs</em>. 61% of cases, respectively). The absolute number of the major T-cell and natural killer cell populations also increased, but only among chronic lymphocytic leukemia-like cases with increased clone size <em>vs</em>. age- and sex-matched controls. Although progression to chronic lymphocytic leukemia was not observed, the overall survival of low-count monoclonal B-cell lymphocytosis individuals was significantly reduced <em>vs</em>. non-monoclonal B-cell lymphocytosis controls (<em>P</em>=0.03) plus the general population from the same region (<em>P</em>≤0.001), particularly among females (<em>P</em&gt;=0.01); infection and cancer were the main causes of death in low-count monoclonal B-cell lymphocytosis. In summary, despite the fact that mid-term progression from low-count monoclonal B-cell lymphocytosis to high-count monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia appears to be unlikely, these clones persist at increased numbers, usually carrying more genetic alterations, and might thus be a marker of an impaired immune system indirectly associated with a poorer outcome, particularly among females.}, number={7}, journal={Haematologica}, author={Ignacio Criado and Arancha Rodríguez-Caballero and M. Laura Gutiérrez and Carlos E. Pedreira and Miguel Alcoceba and Wendy Nieto and Cristina Teodosio and Paloma Bárcena and Alfonso Romero and Paulino Fernández-Navarro and Marcos González and Julia Almeida and Alberto Orfao and The Primary Health Care Group of Salamanca for the Study of MBL}, year={2018}, month={Jul.}, pages={1198-1208} }