title: Translocation (6;9) may be associated with a specific TdT-positive immunological phenotype in ANLL.
abstract: Two patients with acute nonlymphocytic leukemia (ANLL) (FAB-M4) and t(6;9)(p23;q34) are described. Immunological marker analysis revealed a phenotype of HLA-DR+/partly terminal deoxynucleotidyl transferase (TdT)+/CD13+ in both cases and CD33 positivity in one. The expression of CD13 and CD33 by TdT-positive cells was demonstrated by double immunofluorescence staining. Although it has been postulated that TdT plays a role in gene rearrangement, Southern blot analysis performed in one leukemia revealed that both the T cell receptor beta chain genes and the immunoglobulin heavy chain genes were in germ line configuration. Since we could not detect CD13+/TdT+ cells and CD33+/TdT+ cells in control bone marrow samples, double marker analysis was used to detect low numbers of residual leukemic cells during follow-up of one patient. A gradually increasing percentage of CD33+/TdT+ cells was detected in the bone marrow in a period of 6 months before hematological relapse. Although the t(6;9) may not be correlated to a specific French-American-British subtype, it may be associated with TdT-positive ANLL. Since TdT-positive ANLL seems to have a poor outcome, detection of TdT expression in ANLL patients is particularly important for diagnostic purposes. In addition, our results indicate that double immunological marker analysis for a myeloid marker and TdT allows detection of residual disease during follow-up.
authors.affiliation: Department of Cell Biology, Immunology and Genetics, Erasmus University, Rotterdam, The Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: Adriaansen
authors.forename: J J
authors.initials: JJ
authors.lastname: van Dongen
authors.forename: H
authors.initials: H
authors.lastname: Hooijkaas
authors.forename: K
authors.initials: K
authors.lastname: Hählen
authors.forename: M B
authors.initials: MB
authors.lastname: van 't Veer
authors.forename: B
authors.initials: B
authors.lastname: Löwenberg
authors.forename: A
authors.initials: A
authors.lastname: Hagemeijer
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000276:immunology; D001853:Bone Marrow / Q000032:analysis; D002896:Chromosomes, Human, Pair 6; D002899:Chromosomes, Human, Pair 9; D004253:DNA Nucleotidylexotransferase / Q000032:analysis* / Q000276:immunology; D004254:DNA Nucleotidyltransferases / Q000032:analysis*; D005260:Female; D006801:Humans; D007621:Karyotyping; D007938:Leukemia / Q000235:genetics*; D010641:Phenotype; D014178:Translocation, Genetic
chemical_list: D014408:Biomarkers, Tumor; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase