title: Terminal deoxynucleotidyl transferase-positive cells in human tonsils.
abstract: To study the possible cellular origin of recently recognized indolent terminal deoxynucleotidyl transferase (TdT)-positive T-lymphoblastic proliferations of the tonsils and oropharynx, we studied normal human tonsils for the presence of TdT-positive cells. TdT-positive cells were readily demonstrated in the tonsils from 15 children and adults by immunohistochemical staining. TdT-positive cells were distributed in discrete foci at the periphery of lobules of lymphoid tissue and adjacent to fibrous septa and had the morphologic features of small to medium-sized lymphocytes. Double-antibody staining indicated the TdT-positive cells had the phenotype of uncommitted early lymphoid precursors (CD3-, CD79a-, CD10-). Foci of TdT-positive cells were not identified in 6 reactive lymph nodes studied as controls. These studies indicate that tonsils, like bone marrow and thymus, are sites of lymphopoiesis. The presence of TdT-positive precursor cells in human tonsils may be a factor in the pathogenesis of recently described indolent T-lymphoblastic proliferations involving the tonsils and oropharynx. The presence of TdT-positive cells in human tonsils should not be misinterpreted as evidence of lymphoblastic lymphoma or leukemia.
authors.affiliation: Dept of Pathology, Mount Sinai School of Medicine, One Gustave Levy Place, New York, NY 10029, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Strauchen
authors.forename: L K
authors.initials: LK
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D007223:Infant; D008198:Lymph Nodes / Q000201:enzymology / Q000473:pathology; D008875:Middle Aged; D014066:Palatine Tonsil / Q000201:enzymology* / Q000473:pathology
chemical_list: D004254:DNA Nucleotidyltransferases