title: Hospital population screening reveals overrepresentation of CD5(-) monoclonal B-cell lymphocytosis and monoclonal gammopathy of undetermined significance of IgM type.
abstract: Monoclonal B-cell lymphocytosis (MBL) and monoclonal gammopathy of undetermined significance (MGUS) result from clonal expansions of mature B or plasma cells. Here, we set out to determine the immunophenotypic/monoclonal immunoglobulin (M protein) features and co-prevalence of MBL and MGUS in a hospital-based cohort of 1909 non-hematooncological patients. Of the evaluable cases, 3.8 % showed evidence for MBL by immunophenotyping, while 9.8 % were screened positive for M protein by immunofixation. With six concomitant cases (0.4 %), MBL and MGUS were not statistically associated. At least in two of these coincident cases, MBL and MGUS were of different clonal origin since both clones had divergent light chain restriction. CD5(-) MBL (57.1 %) and IgM+ MGUS (24.7 %) were strikingly overrepresented compared to population-based screenings and did not progress to overt lymphoma or myeloma during the observation period (mean follow-up of 117 weeks or 110 weeks, respectively). Prevalence and phenotypes suggest that a substantial proportion of incidental MBL and MGUS in hospitalized patients may be attributed to transiently expanded B-cell clones in the context of disease-related immune stimulation rather than reflecting veritable precursors of clonal B-cell malignancies.
authors.affiliation: Department of Oncology and Hematology, Hubertus Wald Tumorzentrum/UCCH, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
authors.forename: Minna
authors.initials: M
authors.lastname: Voigtlaender
authors.forename: Birthe
authors.initials: B
authors.lastname: Vogler
authors.forename: Martin
authors.initials: M
authors.lastname: Trepel
authors.forename: Jens
authors.initials: J
authors.lastname: Panse
authors.forename: Roman
authors.initials: R
authors.lastname: Jung
authors.forename: Carsten
authors.initials: C
authors.lastname: Bokemeyer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Bacher
authors.forename: Mascha
authors.initials: M
authors.lastname: Binder
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D018956:CD5 Antigens; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D008218:Lymphocytosis / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000097:blood* / Q000175:diagnosis / Q000473:pathology
chemical_list: D018956:CD5 Antigens; D007075:Immunoglobulin M