Increased frequency (12%) of circulating chronic lymphocytic leukemia–like B-cell clones in healthy subjects using a highly sensitive multicolor flow cytometry approach

• Published in: Blood Vol. 114; no. 1; pp. 33 - 37
• Main Authors: Nieto, Wendy G., Almeida, Julia, Romero, Alfonso, Teodosio, Cristina, López, Antonio, Henriques, Ana F., Sánchez, Maria Luz, Jara-Acevedo, María, Rasillo, Ana, González, Marcos, Fernández-Navarro, Paulino, Vega, Tomás, Orfao, Alberto
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 02.07.2009; Americain Society of Hematology
• Subjects: Adult; Aged; Aged, 80 and over; B-Lymphocytes - immunology; B-Lymphocytes - pathology; Biological and medical sciences; Diagnosis, Differential; Disease Progression; Female; Flow Cytometry - methods; Flow Cytometry - statistics & numerical data; Gene Rearrangement, B-Lymphocyte, Heavy Chain; Hematologic and hematopoietic diseases; Humans; Immunophenotyping; Leukemia, Lymphocytic, Chronic, B-Cell - blood; Leukemia, Lymphocytic, Chronic, B-Cell - diagnosis; Leukemia, Lymphocytic, Chronic, B-Cell - genetics; Leukemia, Lymphocytic, Chronic, B-Cell - immunology; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphocyte Count; Lymphocytosis - blood; Lymphocytosis - diagnosis; Lymphocytosis - genetics; Lymphocytosis - immunology; Male; Medical sciences; Middle Aged; Precancerous Conditions - blood; Precancerous Conditions - diagnosis; Precancerous Conditions - genetics; Precancerous Conditions - immunology; Sensitivity and Specificity; Human; Flow cytometry; Chronic lymphocytic leukemia; Hematology; Healthy subject; Lymphoproliferative syndrome; Malignant hemopathy; B-Lymphocyte; Diagnosis; Blood; Cancer; Clone
• ISSN: 0006-4971; 1528-0020; 1528-0020
• DOI: 10.1182/blood-2009-01-197368

Monoclonal B-cell lymphocytosis (MBL) indicates the presence of less than 5 × 109/L circulating monoclonal B cells in otherwise healthy subjects. Recently, it has been reported that circulating chronic lymphocytic leukemia (CLL)–like B cells can be detected using 4- or 5-multicolor flow cytometry in 5% to 7% of adults with normal lymphocyte counts. We investigated the frequency of circulating monoclonal B cells in 608 healthy subjects older than 40 years with normal blood counts, using a highly sensitive 8-color flow cytometry approach and systematic screening for total PB leukocyte count higher than 5 × 106. We show that the frequency of PB monoclonal B cells is markedly higher than previously reported (12% for CLL-like B cells, found at frequencies of 0.17 ± 0.13 × 109 cells/L), the incidence progressively increasing with age. Most cases (62%) showed clonal B-cell levels below the maximum sensitivity of the techniques described by others (< 0.01%), supporting the notion that detection of MBL may largely depend on the sensitivity of the flow cytometry approach used.