title: Characterization of Thy-1 (CDw90) expression in CD34+ acute leukemia.
abstract: Thy-1 (CDw90) is a phosphatidylinositol-anchored cell surface molecule which, when coexpressed with CD34 in normal human bone marrow, identifies a population of immature cells that includes putative hematopoietic stem cells. To date, the characterization of Thy-1 expression has been confined largely to normal tissues and cell lines. In this study, we evaluated the frequency and intensity of Thy-1 expression as defined by reactivity with the anti-Thy-1 antibody 5E10 in 38 cases of CD34+ acute leukemia (21 acute myelogenous leukemia [AML], 8 chronic myelogenous leukemia [CML] in blast crisis, and 9 acute lymphoblastic leukemia [ALL]). In 34 of 38 cases (89%) the CD34+ cells lacked expression of the Thy-1 antigen. High-density Thy-1 expression was found in 1 case of CML in lymphoid blast crisis, and low-density Thy-1 expression was identified on a portion of the leukemic cells in 2 cases of AML with myelodysplastic features, and 1 case of CML in myeloid blast crisis, suggesting a possible correlation between Thy-1 expression and certain instances of stem cell disorders such as CML and AML with dysplastic features. In contrast, the dissociation of Thy-1 and CD34 expression in the majority of acute leukemias studied suggests that the development of these leukemias occurs at a later stage than the hematopoietic stem cell. Characterization of Thy-1 expression in acute leukemia may eventually provide insights into the origin of the disease. In addition, separation of leukemic blasts from normal stem cells based on Thy-1 expression may prove useful in assessing residual disease, as well as in excluding leukemic blasts from stem cell preparations destined for autologous bone marrow or peripheral stem cell transplantation.
authors.affiliation: Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Holden
authors.forename: R B
authors.initials: RB
authors.lastname: Geller
authors.forename: D C
authors.initials: DC
authors.lastname: Farhi
authors.forename: H K
authors.initials: HK
authors.lastname: Holland
authors.forename: L L
authors.initials: LL
authors.lastname: Stempora
authors.forename: C N
authors.initials: CN
authors.lastname: Phillips
authors.forename: R A
authors.initials: RA
authors.lastname: Bray
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000782:Aneuploidy; D015703:Antigens, CD / Q000096:biosynthesis*; D018952:Antigens, CD34; D000951:Antigens, Neoplasm / Q000096:biosynthesis* / Q000235:genetics; D001752:Blast Crisis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D002648:Child; D002675:Child, Preschool; D005260:Female; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007951:Leukemia, Myeloid / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018800:Thy-1 Antigens / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D000951:Antigens, Neoplasm; D018800:Thy-1 Antigens