title: The clonal hierachy in multiple myeloma.
abstract: In this report we evaluated the number and phenotype of blood circulating B-cell subsets at different stages of differentiation in 26 patients with newly diagnosed multiple myeloma (MM). In all patients, plasma cells and/or plasma blasts could be identified by flow cytometry with a mean frequency of 1.20% and 0.07%, respectively. In 76.9% of the patients these cells showed aberrant expression mainly of CD56, CD28 and CD117, none of these markers were found on the earlier B-lymphocytes. Clonal B-cells preceding the plasma blast stage were identified by patient specific IgH RT-PCR on sorted B-cell subsets. The clonal cells included the less differentiated CD38+ CD19+ and CD38-/CD19+ subsets. illustrating that the clonal cells are part of an ongoing differentiation process. Further, the presence of CD38-/CD19+ cells with somatically mutated Cgamma transcripts identical to the tumor-specific Calpha transcript, shows that the clonal hierarchy in myeloma may include memory B-cells.
authors.affiliation: Department of Hematology L, Herlev Hospital, University of Copenhagen, Denmark. thra@herlevhosp.kbhamt.dk
authors.forename: T
authors.initials: T
authors.lastname: Rasmussen
authors.forename: L
authors.initials: L
authors.lastname: Jensen
authors.forename: H E
authors.initials: HE
authors.lastname: Johnsen
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD; D018941:Antigens, CD19 / Q000032:analysis; D000943:Antigens, Differentiation / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D002999:Clone Cells / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D008562:Membrane Glycoproteins; D009101:Multiple Myeloma / Q000276:immunology / Q000473:pathology*; D009244:NAD+ Nucleosidase / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015703:Antigens, CD; D018941:Antigens, CD19; D000943:Antigens, Differentiation; D008562:Membrane Glycoproteins; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1