Increased frequency (12%) of circulating chronic lymphocytic leukemia-like B-cell clones in healthy subjects using a highly sensitive multicolor flow cytometry approach.
Monoclonal B-cell lymphocytosis (MBL) indicates the presence of less than 5 x 10(9)/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 x 10(6). 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 x 10(9) 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.
Instituto de Biología Molecular y Celular del Cáncer, Centro de Investigación del Cáncer/IBMCC (CSIC-USAL), Department of Medicine, University of Salamanca, Salamanca, Spain.
Wendy G
WG
Nieto
Julia
J
Almeida
Alfonso
A
Romero
Cristina
C
Teodosio
Antonio
A
López
Ana F
AF
Henriques
Maria Luz
ML
Sánchez
María
M
Jara-Acevedo
Ana
A
Rasillo
Marcos
M
González
Paulino
P
Fernández-Navarro
Tomás
T
Vega
Alberto
A
Orfao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000276:immunology / Q000473:pathology*; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005434:Flow Cytometry / Q000379:methods / Q000706:statistics & numerical data; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D006801:Humans; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood* / Q000175:diagnosis / Q000235:genetics / Q000276:immunology; D018655:Lymphocyte Count; D008218:Lymphocytosis / Q000097:blood* / Q000175:diagnosis / Q000235:genetics / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000097:blood / Q000175:diagnosis / Q000235:genetics / Q000276:immunology; D012680:Sensitivity and Specificity