title: Monoclonal B-cell lymphocytosis in blood donors.
abstract: Monoclonal B-cell populations have been detected in the peripheral blood of apparently healthy individuals by flow cytometry. In 2005, the term monoclonal B-cell lymphocytosis (MBL) was proposed to describe these findings. MBL may be immunophenotypically similar to chronic lymphocytic leukaemia (CLL) and, like CLL, the prevalence is higher in males and older individuals. We studied the prevalence of MBL in blood donors from the Midwestern United States. Samples from 5141 donors were examined and seven (0.14%) were found to have immunophenotypic characteristics of MBL or CLL. Immunoglobulin heavy chain analysis yielded monoclonality or oligoclonality. Prior and subsequent to the study, an additional undetermined number of blood donors were screened and seven of these expressed immunophenotypic characteristics of MBL or CLL. We thus found a total of 14 healthy blood donors with monoclonal expansions of B-lymphocyte populations. Of these, 12 were presumptively classified as MBL and two as CLL. All but two of the donors were male; the mean age was 59 years. The clinical importance of these findings with regard to transfusion medicine has not been established.
authors.affiliation: Saint Luke's Hospital, Kansas City, MO, USA. jrachel@saint-lukes.org
authors.forename: Jane M
authors.initials: JM
authors.lastname: Rachel
authors.forename: Marjorie L
authors.initials: ML
authors.lastname: Zucker
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Fox
authors.forename: Fred V
authors.initials: FV
authors.lastname: Plapp
authors.forename: Jay E
authors.initials: JE
authors.lastname: Menitove
authors.forename: Fatima
authors.initials: F
authors.lastname: Abbasi
authors.forename: Gerald E
authors.initials: GE
authors.lastname: Marti
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes; D001782:Blood Donors / Q000706:statistics & numerical data*; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D016130:Immunophenotyping; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000453:epidemiology*; D008218:Lymphocytosis / Q000453:epidemiology* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D017678:Sex Distribution; D014481:United States / Q000453:epidemiology