title: Aberrant phenotypes in acute myeloid leukemia: a high frequency and its clinical significance.
abstract: OBJECTIVE
  Immunophenotyping is an essential method for diagnosis and classification of acute myeloid leukemias (AML), and its extensive use could identify blast cell subpopulations with aberrant phenotypes rarely seen in normal myelopoiesis. The aberrant phenotypes have been correlated with clinical, morphological and prognostic features but their occurrence in AML differs in the various studies.
  
  
  METHODS
  In this study, we analyzed 35 cases of AML, examining them for aberrant phenotypes by multiparametric flow cytometry. Co-expression of lymphoid-associated markers in myeloblasts and asynchronous antigen expression were correlated with clinical features.
  
  
  RESULTS
  Aberrant phenotypes were found in 88.6% of the cases studied. In this group, cross-lineage antigen expression was present in 34.3% and asynchronous expression in 82.4% of the cases. CD7 was the most frequent lymphoid-associated antigen. Among the cases of asynchronous antigen expression, the most frequent phenotype was CD117(+) and/or CD34(+) in association with CD11c(+), followed by CD15(+) and CD65(+), corresponding to 67.6%, 61.7 and 50.0% of the cases, respectively. Twenty out of 33 patients were available for complete remission assessment. The CD117(+) CD15(+) phenotype correlated significantly with complete remission achievement and with the lack of unfavorable chromosome associations.
  
  
  CONCLUSIONS
  We conclude that aberrant phenotypes, as they are described here, are present in the great majority of cases of AML, asynchronous antigen expression being the most frequent example; and that CD117(+) CD15(+) phenotype shows a relevant association with clinical prognosis.
authors.affiliation: Disciplina de Hematologia e Hemoterapia, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, Brasil.
authors.forename: D M
authors.initials: DM
authors.lastname: Bahia
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: M de L
authors.initials: Mde L
authors.lastname: Chauffaille
authors.forename: E Y
authors.initials: EY
authors.lastname: Kimura
authors.forename: J O
authors.initials: JO
authors.lastname: Bordin
authors.forename: M A
authors.initials: MA
authors.lastname: Filgueiras
authors.forename: J
authors.initials: J
authors.lastname: Kerbauy
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D001854:Bone Marrow Cells / Q000276:immunology / Q000473:pathology; D015331:Cohort Studies; D020732:Cytogenetic Analysis; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007951:Leukemia, Myeloid / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D008875:Middle Aged; D011379:Prognosis
chemical_list: D015703:Antigens, CD