Marrow B-cell precursors are increased in lymphomas or systemic diseases associated with B-cell dysfunction.
Marrow regeneration is known to be associated with an increase in immature B cells, including CD10+ cells. A similar phenotype has been seen in some children with unusual cytopenias. This article describes 21 adult patients not recovering from chemotherapy, who had increased CD10+ cells in their marrows. These cells had the relatively uniform scatter properties of small lymphocytes by flow cytometry, and by multiparameter analysis were found to have a distinct phenotype in that they were CD19+, lacked surface immunoglobulin, and heterogeneity expressed CD20. In two of three patients tested, some but not all of these early B cells were TdT+. CD10+ cells accounted for 10-76% of total mononuclear cells. All 21 patients had some systemic illness. Thirteen patients had a diagnosis of lymphoma (three Hodgkin's, ten non-Hodgkin's); all ten of the latter were extranodal and seven of seven phenotyped cases were B-cell lymphomas. Seven patients had autoimmune disease (one also had lymphoma) and one had the acquired immunodeficiency syndrome with mycobacterial infection of the marrow. One patient with a history of a "viral illness" had a lymph node showing atypical lymphoid hyperplasia with progressive transformation of germinal centers. Examination of marrow core biopsies in these patients showed a proliferation of small lymphocytes ranging from a barely perceptible diffuse increase to numerous lymphoid aggregates. The extensive lymphocytosis seen in two marrows suggested a diagnosis of lymphoma on morphologic grounds alone, but neither these patients nor any others had B-cell clonal excess. The presence of this phenotype suggests nonspecific stimulation of marrow B-cell precursors associated with systemic B-cell activation in either an immunologic or neoplastic disorder. Presence of this unusual phenotype does not imply involvement of marrow by B-cell neoplasia.
Vandersteenhoven
A M
AM
Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710.
Williams
J E
JE
Borowitz
M J
MJ
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology*; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D016393:Lymphoma, B-Cell / Q000276:immunology*; D008297:Male; D008875:Middle Aged