title: Severe deficiency of B lymphocytes in peripheral blood from multiple myeloma patients.
abstract: A major problem in the assessment of circulating B lymphocytes in multiple myeloma is the extent to which cells with passively absorbed Ig contribute to the assay. We have analyzed peripheral blood B cell numbers in 51 patients in various treatment categories by using an assay that is not subject to artifacts involving cytophilic Ig. We have defined a B lymphocyte by three different criteria (a) expression of a high surface density of Ig (b) expression of a high density of HLA.DR and (c) expression of a marker exclusive to surface Ig+ B cells. By these criteria, normal individuals have an average of 6% B cells. In multiple myeloma patients, B cell levels in purified mononuclear cell preparations are severely reduced. Untreated patients and the majority of patients on intermittent chemotherapy have 20-600-fold fewer B cells than do normal donors (average = 0.3%). This decrease was even greater in whole blood of patients as compared with normal donors (100-1,000-fold fewer B cells). The number of B cells did not correlate with disease status or paraprotein concentration. We found no evidence to support the idea that B lymphocytes in patients include a substantial monoclonal subset.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007130:Immunoglobulin Idiotypes / Q000032:analysis; D007152:Immunologic Capping; D007958:Leukocyte Count; D008231:Lymphopenia / Q000097:blood* / Q000276:immunology; D009101:Multiple Myeloma / Q000097:blood* / Q000276:immunology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
chemical_list: D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007130:Immunoglobulin Idiotypes; D011947:Receptors, Antigen, B-Cell