title: CD20 (pan-B cell antigen) expression on bone marrow-derived T cells.
abstract: Antibodies directed against CD20 (L26, Leu 16, and B1) are frequently used to determine the presence of B lymphocytes. However, recent publications describe the unexpected presence of CD20-positive T cells in the peripheral blood of normal subjects and occasional T-cell neoplasms that express CD20. To determine the presence of CD20-positive T cells in bone marrow, flow cytometric analysis was performed on 34 aspirate specimens (14 normal, 5 acute lymphoblastic lymphoma [ALL], 5 acute myelogenous leukemia [AML], 4 HIV positive, 2 myelodysplastic/myeloproliferative, 2 chronic myelogenous leukemia [CML], 1 chronic lymphocytic lymphoma [CLL], 1 multiple myeloma). A small population of cells coexpressing CD3 (Leu 4) and CD20dim (Leu 16) was identified in 94% of the specimens, representing 0% to 11% (mean 1.77%) of marrow mononuclear cells and 0% to 22.2% (mean 6.54%) of marrow lymphoid cells. There was no correlation between the percentage of CD20-positive T cells and the CD4:CD8 ratio, patient age, gender, or diagnosis. CD20dim positive cells included immature B cells and CD20-positive T cells. Although evaluation of CD20 expression is useful in delineating B-cell processes, caution should be exercised in interpreting its expression on bone marrow T-lymphoid cells. CD20 expression on T cells may be seen in either normal, reactive, or neoplastic processes.
authors.affiliation: Department of Pathology, University of Texas Health Science Center, San Antonio 78284, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Algino
authors.forename: R W
authors.initials: RW
authors.lastname: Thomason
authors.forename: D E
authors.initials: DE
authors.lastname: King
authors.forename: M M
authors.initials: MM
authors.lastname: Montiel
authors.forename: F E
authors.initials: FE
authors.lastname: Craig
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018951:Antigens, CD20 / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D001853:Bone Marrow / Q000737:chemistry / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013601:T-Lymphocytes / Q000737:chemistry / Q000276:immunology*
chemical_list: D018951:Antigens, CD20; D015415:Biomarkers; D014408:Biomarkers, Tumor