title: Expression of the myeloid-associated marker CD33 is not an exclusive factor for leukemic plasmacytoid dendritic cells.
abstract: A new entity of acute leukemia coexpressing CD4(+)CD56(+) markers without any other lineage-specific markers has been identified recently as arising from lymphoid-related plasmacytoid dendritic cells (pDCs). In our laboratory, cells from a patient with such CD4(+)CD56(+) lineage-negative leukemia were unexpectedly found to also express the myeloid marker CD33. To confirm the diagnosis of pDC leukemia despite the CD33 expression, we demonstrated that the leukemic cells indeed exhibited pDC phenotypic and functional properties. In 7 of 8 other patients with CD4(+)CD56(+) pDC malignancies, we were able to confirm that the tumor cells expressed CD33 although with variable expression levels. CD33 expression was shown by flow cytometry, reverse transcriptase-polymerase chain reaction, and immunoblot analysis. Furthermore, CD33 monoclonal antibody stimulation of purified CD4(+)CD56(+) leukemic cells led to cytokine secretion, thus confirming the presence of a functional CD33 on these leukemic cells. Moreover, we found that circulating pDCs in healthy individuals also weakly express CD33. Overall, our results demonstrate that the expression of CD33 on CD4(+)CD56(+) lineage-negative cells should not exclude the diagnosis of pDC leukemia and underline that pDC-specific markers should be used at diagnosis for CD4(+)CD56(+) malignancies.
authors.affiliation: Etablissement Français du Sang Bourgogne Franche-Comté, Unité mixte EFS/Université EA2284/Inserm U645, IFR133, Besançon, France.
authors.forename: Francine
authors.initials: F
authors.lastname: Garnache-Ottou
authors.forename: Laurence
authors.initials: L
authors.lastname: Chaperot
authors.forename: Sabeha
authors.initials: S
authors.lastname: Biichle
authors.forename: Christophe
authors.initials: C
authors.lastname: Ferrand
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Remy-Martin
authors.forename: Eric
authors.initials: E
authors.lastname: Deconinck
authors.forename: Patrick Darodes
authors.initials: PD
authors.lastname: de Tailly
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Bulabois
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Poulet
authors.forename: Emilienne
authors.initials: E
authors.lastname: Kuhlein
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Jacob
authors.forename: Véronique
authors.initials: V
authors.lastname: Salaun
authors.forename: Michel
authors.initials: M
authors.lastname: Arock
authors.forename: Bernard
authors.initials: B
authors.lastname: Drenou
authors.forename: Françoise
authors.initials: F
authors.lastname: Schillinger
authors.forename: Estelle
authors.initials: E
authors.lastname: Seilles
authors.forename: Pierre
authors.initials: P
authors.lastname: Tiberghien
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Bensa
authors.forename: Joel
authors.initials: J
authors.lastname: Plumas
authors.forename: Philippe
authors.initials: P
authors.lastname: Saas
mesh_terms: D000208:Acute Disease; D000368:Aged; D015703:Antigens, CD / Q000097:blood*; D015214:Antigens, Differentiation, Myelomonocytic / Q000097:blood*; D014408:Biomarkers, Tumor / Q000276:immunology; D017252:CD3 Complex / Q000097:blood; D015704:CD4 Antigens / Q000097:blood; D018958:CD55 Antigens / Q000097:blood; D003713:Dendritic Cells / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007952:Leukemia, Plasma Cell / Q000276:immunology; D008297:Male; D010950:Plasma Cells / Q000276:immunology*; D063268:Sialic Acid Binding Ig-like Lectin 3
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D014408:Biomarkers, Tumor; D017252:CD3 Complex; C571163:CD33 protein, human; D015704:CD4 Antigens; D018958:CD55 Antigens; D063268:Sialic Acid Binding Ig-like Lectin 3