title: Instability of immunophenotype in plasma cell myeloma.
abstract: Little information has been reported describing antigen stability in plasma cell myeloma. In this study, the expression frequency and stability of 2 potential therapeutic targets, CD20 and CD52, along with the frequently aberrantly expressed CD56 antigen, were evaluated by flow cytometric analyses in 56 patients with plasma cell myeloma. Of the 56 patients, 23 (41%) showed immunophenotype change, including CD56 in 6 cases, CD20 in 7 cases, and CD52 in 17 cases. Combined CD56/CD52 change was seen in 3 cases and combined CD20/CD52 in 4 cases. No correlation was found between immunophenotype change and age, sex, stage, plasma cell morphologic features, extent of marrow involvement, time between analyses, type of therapy, or response to therapy. Immunophenotype shift was more common in patients with IgA than in patients with IgG paraprotein. Recognition of lack of stability in immunophenotype may be important, especially in antigen-directed treatment decisions and when specific phenotypes are used to detect residual disease.
authors.affiliation: Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Cao
authors.forename: Charles L
authors.initials: CL
authors.lastname: Goolsby
authors.forename: Beverly P
authors.initials: BP
authors.lastname: Nelson
authors.forename: Seema
authors.initials: S
authors.lastname: Singhal
authors.forename: Jayesh
authors.initials: J
authors.lastname: Mehta
authors.forename: Loann C
authors.initials: LC
authors.lastname: Peterson
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000276:immunology*; D018951:Antigens, CD20 / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001854:Bone Marrow Cells / Q000276:immunology / Q000473:pathology; D000074301:CD52 Antigen; D019002:CD56 Antigen / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D009367:Neoplasm Staging; D010950:Plasma Cells / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D018951:Antigens, CD20; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D000074301:CD52 Antigen; C000613862:CD52 protein, human; D019002:CD56 Antigen; D006023:Glycoproteins