title: CD5 positive immunoregulatory B cells in spleen populations from multiple myeloma patients.
abstract: CD19+CD5+ lymphocytes constitute a minority of peripheral blood B cells. In view of the importance of these cells in the pathogenesis of the immunoregulation of myeloma, their incidence in another lymphoid organ was determined. CD5+ B cells were studied in 9 spleens from patients with multiple myeloma and in 10 spleens from normal individuals removed secondary to trauma. The total number of CD19+ B cells were increased in myeloma spleens (44.4% +/- 12.6%) as compared to normal spleens (20.4% +/- 7.4%). Likewise, the percentage of CD19 cells which co-expressed CD5 were increased in myeloma (25.3% +/- 12.4%) versus normal (4.4% +/- 2.3%) spleen. CD5+ B cells isolated from myeloma spleens, but not normal spleens, inhibit production of immunoglobulin in a pokeweed mitogen driven assay. Thus the spleen appears to be an important source of immunoregulatory B cells in multiple myeloma.
authors.affiliation: Division of Hematology and Oncology, University of California, Davis School of Medicine, Sacramento.
authors.forename: M R
authors.initials: MR
authors.lastname: MacKenzie
authors.forename: T
authors.initials: T
authors.lastname: Paglieroni
authors.forename: V
authors.initials: V
authors.lastname: Caggiano
mesh_terms: D000943:Antigens, Differentiation / Q000032:analysis*; D001402:B-Lymphocytes / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D018956:CD5 Antigens; D006801:Humans; D009101:Multiple Myeloma / Q000473:pathology*; D013154:Spleen / Q000166:cytology*
chemical_list: D000943:Antigens, Differentiation; D018956:CD5 Antigens